Economics - Copy

A waste heat recovery boiler produces 4.8 Mpa (dry saturated) steam from 104 deg.C feedwater. The boiler receive energy from 7kg/sec of 954deg.C dry air. After passing through a waste heat boiler, the temperature of the air is has been reduced to 343deg.C. How much steam in kg is produced per second? Note: at 4.80Mpa dry saturated, h=2796.

A. 1.30 B. 0.92 C. 1.81 D. 3.43

A diesel electric plant supplies energy for Meralco. During a 24-hour period, the plant consumed 240 gallons of fuel at 28deg.C and produced 3930kw-hr industrial fuel used is 28API and was purchased at P30/liter at 15.6deg.C. what is the cost of fuel to be produce one kw-hr?

A. B. C. D.

P6.87 P1.10 P41.07 P5.00

In a gas turbine unit, air enters the combustion chamber at 550kpa, 277deg.C and 43m/s. The products of combustion leave the combustor at 511kpa, 1004deg.C and 180 value of 43,000kj/kg. for fuel-air ratio of 0.0229, what is the combustor efficiency of the unit in percent?

A. B. C. D.

70.38% 79.38% 75.38% 82.38%

The specific speed of turbine is 85rpm and running at 450rpm. If the head is 20m and generator efficiency is 90% what is the maximum power delivered by the generator?

A. B. C. D.

450.51 kw 354.52 kw 650.53 kw 835.57 kw

In the Francis turbine, the pressure gage leading to the turbine casing reads 380kpa. The velocity of water entering the turbine is 8m/s, if net head of the turbine is 45m, find the distance from the center of spiral casing to the tailrace?

A. B. C. D.

3.0m 3.5m 4.0m 4.5m

A turbine has a mechanical efficiency of 93%, volumetric efficiency of 95%, and total efficiency of 82%. If the effective head is 40m, find the total head?

A. B. C. D.

48.72 40.72 36.22 34.72

In an 9,000 kw hydro-electric plant the overall efficiency is 88% and actual power receive by the customer is 110,000 kw-hrs for that day. What is the secondary power could this plant deliver during the entire day?

A. B. C. D.

58,960 kw-hrs 80,080 kw-hrs 65,960 kw-hrs 78,960 kw-hrs

A pelton type turbine has 25m head friction loss of 4.5m. The coefficient of friction head loss (from morse) is 0.00093 and penstock length of 80m, what is the penstock diameter?

A. B. C. D.

1,355.73mm 3,476.12mm 6,771.23mm 1686.73mm

A pelton type turbine was installed 30m below the head gate of the penstock. The head loss due to friction is 12percent of the given elevation, the length of penstock is 100m and coefficient of friction is 0.00093. determine the power output in kw. (use morse-equation).

A. B. C. D.

22,273 23,234 32,345 34,452

Water flows steadily with a velocity of 3.05m/s in as horizontal pipe having a diameter of 25.24cm. At one section of the pipe, the temperature and pressure of the water are 21deg.C and 689.3 kpa, respectively. At a distance of 304.8m downstream, the pressure is 516.9 kpa. What is the friction factor?

A. B. C. D.

0.134 0.0050 0.0307 .0641

A hydro-electric plant having 30sq.km reservoir area and 100m head is used to generate power. The energy utilized by the consumers whose load is connected to the power plant during a five-hour period is 13.5 x106 kwh. The overall generation efficiency is 75%. Find the fall in .height of water in the reservoir after the 5-hour period

A. B. C. D.

5.13m 1.32m 3.21m 2.2m

The gas density of chimney is 0.75kg/m3 and air density of 1.15kg/m3 . find the driving pressure if the height of chimney is 63.71m

A. B. C. D.

0.15kpa 0.25kpa 0.35kpa 0.45kpa

The actual velocity of gas entering in a chimney is 8m/sec. the gas temperature is 25deg.C with a gas constant of 0.287 kj/kg-K. determine the gas pressure for a mass of gas is 50,000 kg/hr and chimney diameter of 1.39m

A. B. C. D.

95 kpa 98 kpa 101 kpa 92 kpa

a steam generator with economizer and air heater has an overall draft loss of 25.73cm of water. If the stack gases are at 177degC and if the atmosphere is at 101.3 kpa and 26deg.C, what theoretical height of stack in meters is needed when no draft fan are used? Assume that the gas constant for the flue gases is the same as that for air?

A. B. C. D.

611.10 631.10 651.10 671.10

A foundation measures 12ft x 14ft x 16ft find the number of sacks of cement needed for 1:2:4 mixture.

A. B. C. D.

302 598 356 404

A rectangular foundation cross-section has a bed plate dimension of 8ft x 10ft. The uniform clearance on each side 1ft the height of foundation is 4.5ft if the weight of the steel bar reinforcements needed is ½% of weight of foundation, find the weight of steel bars. Use concrete density of 2400kg/m3

A. B. C. D.

173.47 kg 183.47 kg 163.47 kg 153.47 kg

The initial condition of air in an air compressor is 98kpa and 27deg.C and discharges air at 450kpa. The bore and stroke are 335mm and 381mm respectively with percent clearance of 8% running at 300rpm. Find the volume of air at suction.

A. B. C. D.

541.62 m3/hr 551.62m3/hr 561.62m3/hr 571.62m3/hr

An air compressor has a suction volume of 0.35 m3 /sec at 97kpa and discharges to 650kpa . How much power saved by the compressor if there are two stages?

A. B. C. D.

18.27kw 16.54 kw 13.86kw 11.58kw

A two stages air compressor has an intercooler pressure of 4kg/cm2 . What is the discharge pressure if suction pressure is 1kg/cm2?

A. B. C. D.

3 kg/cm2 9 kg/cm2 12 kg/cm2 16kg/cm2

A two stage air compressor air at 100 kpa and 22deg.C discharges to 750kpa. If intercooler intake is 105deg.C , determine the value of n.

A. B. C. D.

1.400 1.288 1.345 1.326

A single acting air compressor has a volumetric efficiency of 89%, operates at 500rpm. It takes in air at 100kpa and 30deg.C and discharges it at 600 kpa. The air handled is 8m3 /min measured at discharge condition. If compression is isentropic, find mean effective pressure in kpa.

A. B. C. D.

233.34 973.17 198.34 204.82

A water-jacketed air compressor handles 0.343 m3/s of air entering at 96.5kpa and 21deg.C and leaving at 480kpa and 132deg.C , 10.9kg/h of cooling water enters the jacket at 15deg.C and leaves at 21deg.C. determine the compressor brake power?

A. B. C. D.

26.163 kw 62.650 kw 34.44 kw 19.33 kw

A double suction centrifugal pumps delivers 20 ft3/sec of water at a head of 12m and running at 650rpm. What is the specific speed of the pump?

A. B. C. D.

5014.12 rpm 6453.12 rpm 2770.73 rpm 9968.73 rpm

Determine the number of stages needed for a centrifugal pump if it is used to deliver 400ga/min of water and pump power of 15hp . Each impeller develops a head of 30ft.

A. B. C. D.

6 7 5 4

the suction pressure of a pump reads 3in of mercury vacuum and discharge pressure reads 140psi is use to deliver 120gpm of water with specific volume of 0.0163 ft3/lb . Determine the pump work?

A. B. C. D.

4.6 kw 5.7 kw 7.4 kw 8.4 kw

A submersible pump delivers 350rpm of water to a height of 5 ft from the ground. The pump were installed 150 ft below the ground level and a draw down of 8 ft during the operation. If the water level is 25 ft above the pump, determine the pump power.

A. B. C. D.

7.13 kw 4.86 kw 7.24 kw 9.27 kw

A vacuum pump is used to drain a flooded mine shaft of 20deg.C water. The pump pressure of water at this temperature is 2.34 kpa. The pump is incapable of lifting the water higher than 16m. What is the atmospheric pressure?

A. B. C. D.

159.30 132.33 198.22 171.9

A submersible multi-stage centrifugal deep well pump 260gpm capacity is installed in a well 27 feet below the static water level and running at 3000rpm. Drawdown when pumping at rated capacity is 10 feet. The pump delivers a water into 25,000 gallons capacity overhead storage tank. Total discharge head developed by pump including friction in piping is 243 feet calculate the diameter of the impeller of this pump in inches if each impeller diameter developed a head of 38ft. A. B. C. D.

3.28 5.33 3.71 6.34

A fan draws 1.42 m3 per second of air at a static pressure of 2.54cm of water through a duct 300mm diameter and discharges it through a duct of 275mm diameter. Determine the static fan efficiency if total fan mechanical is 75% and air measured at 25deg.C and 760mm

A. B. C. D.

50.11% 53.69% 65.67% 45.43%

A water cooler uses 50lb/hr of melting ice to cool running water from 80deg.F to 42deg.F. based on the inside coil area, u1=110 btu/hr-ft2-f. find the gpm of water cooled.

A. B. C. D.

0.10 gpm 0.21 gpm 0.38 gpm 0.45 gpm

The charge in diesel engine consists of 10.34 grams of fuel with lower heating value of 42,571 kj/kg and 409 grams of fuel and products of combustion. At the beginning of compression, t1= 60deg.C . Let rk = 14. for constant cp = 1.11 kj/kg-c what should be the cut-off ratio in the corresponding ideal cycle?

A. B. C. D.

2.05 2.97 5.34 2.34

The gain entropy during isothermal nonflow process of 5lb of air at 60deg.f is 0.462 btu/R. find v1/v2?

A. B. C. D.

3.85 0.296 1.0 0.259

An auditorium seating 1500 people is to be maintained at 80deg.F dry bulb and 65deg.F wet bulb temperature when outdoor air is at 91deg.F drybulb and 75deg.F wet bulb . Solar heat load is 110,000 btu/hr and supply air is at 60deg.F, determine the amount of supply air.

A. B. C. D.

93,229.17 lb/hr 83,229.17 lb/hr 73,229.17 lb/hr 63,229.17 lb/hr

In an brayton cycle that operates between temperature limits of 300deg.K and 1173K with k = 1.4, determine the temperature at the end of compression (isentropic) for maximum work of the cycle.

A. B. C. D.

700K 690.5K 730K 350K

At 35% solution leaves the absorber and 30% solution enters the absorber. The heat removed from the absorber by cooling water is 547.6btu and ammonia is superheated by 10deg. Find the pound per pound of ammonia gas from the evaporating coils.

A. B. C. D.

11 14 13 12

A carnot refrigeration system operates at tmax/tmin = 1:5. find the kw per ton of refrigeration?

A. B. C. D.

1.91 2.15 1.76 1.55

Assume 8 ft3 of air at 100psi, 100deg.F are compressed isothermally to a volume of 2 ft3. for each of end states the process find the bulk modulus.

A. B. C. D.

400 and 100 psi 400 and 110 psi 400 and 120 psi 400 and 130 psi

A empty open can is 30cm high with a 15 cm diameter. The can, with the open end down, is pushed under water with a density of 1000 kg/m3. find the water level in the can when the top of the can is 50 cm below the surface.

A. B. C. D.

17.20 cm 2.12 cm 4.20 cm 5.87 cm

A cylindrical pipe with water flowing downward at 0.03 m3/s having top diameter of 0.08, bottom diameter of 0.04 m and height of 1.5m . Find the pressure between the pipe.

A. B. C. D.

154.63 kpa 197.93 kpa 252.44 kpa 243.92 kpa

Determine the size of pipe which will deliver 8 liters of medium oil (v = 6.10 x 10-6 m2/s) assuming laminar flow conditions.

A. B. C. D.

622. mm 754 mm 950 mm 835 mm

The type of flow occupying in a 1 cm diameter pipe which water flows at a velocity of 2.50 m/s . Use v = 1.13 x 10-6 m2/s of water.

A. B. C. D.

Turbulent constant laminar none of these

What force is exerted by water jet 60 mm diameter if it strikes a wall at the rate of 15 m/s?

A. B. C. D.

636.17 N 4421.62 N 764.23 N 563.34 N

A 300 mm diameter pipe discharges water at the rate of 200 l/s . Point 1 on the pipe has a pressure of 260kpa and 3.4 m below point 1 is point 2 with a pressure of 300 kpa. Compute the head loss between points 1 and 2.

A. B. C. D.

4.29 m 2.59 m 6.32 m 1.87 m

Water flowing at the rate of 10m/s from an orifice at bottom of a reservoir find the pressure at the bottom of reservoir.

A. B. C. D.

30 kpag 60 kpag 50 kpag 40 kpag

Steam flows through a nozzle at 400C and 1 Mpa ( h = 3263.9 kj/kg) with velocity of 300 m/s . Find the stagnation enthalpy.

A. B. C. D.

3300 kj/kg 3290 kj/kg 3320 kj/kg 3309 kj/kg

Air flow through a nozzle at a speed of 350 m/s . Find the stagnation temperature if entrance temperature is 200C.

A. B. C. D.

241.25 C 251.25 C 261.25 C 271.25C

Carbon dioxide flows through a nozzle with a speed of 100 m/s . Compute the dynamic temperature.

A. B. C. D.

92.56 K 94.56 K 96.56 K 98.56 K

Carbon dioxide flows through a nozzle with a speed of 380 m/s. the entrance condition of nozzle is 250C and 1200 kpa. Find the stagnation pressure.

A. B. C. D.

2,136.34 kpa 2,146.34 kpa 2,156.34 kpa 2,166.34 kpa

Air enters a diffuser with a velocity of 200 m/s . Determine the velocity of sound if air temperature is 30C.

A. B. C. D.

349 m/s 359 m/s 369 m/s 379 m/s

Air flows through a nozzle with temperature of entrance of 420K stagnation temperature of 468K . Find the mach number.

A. B. C. D.

0.744 0.754 0.764 0.774

Air at 300K and 200 kpa is heated at constant pressure to 600K . Determine the change of internal energy.

A. B. C. D.

245.58 kj/kg 235.58 kj/kg 225.58 kj/kg 215.58 kj/kg

An insulated rigid tank initially contains 1.5lb of helium at 80F and 50 psia. A paddle wheel with power rating of 0.02 hp is operated within the tank for 30 min. determine the final temperature.

A. B. C. D.

159.22 F 235.58 F 179.22 F 189.22 F

A 4 m2 asphalt pavement with emissive of 0.85 has a surface temperature of 50C. Find the maximum rate of radiation that can be emitted from the surface.

A. B. C. D.

2,068.32 watts 2,078.32 watts 2,088.32 watts 2,098.32 watts

Air at 10C and 80 kpa enters a diffuser of a jet engine steadily with a velocity of 200 m/s . The inlet area of diffuser is 0.40 m2. determine the mass flow rate of air.

A. B. C. D.

72.79 kg/s 74.79 kg/s 76.79 kg/s 78.79 kg/s

Consider a refrigeration whose 40 watts light bulb remains on continuously as a result of a malfunction of the switch. If the refrigerator has a COP of 1.3 and the cost of electricity is 8 cents per kw-hr, determine the increase in the energy consumption of the refrigerator and its cost per year if the switch is not fixed.

A. B. C. D.

P49.59 P47.59 P45.59 P43.59

A 75 hp motor that has an efficiency of 91% Is worn out and is replaced by a high-efficiency motor that has an efficiency of 95.4%. Determine the reduction in heat gain of the room due to higher efficiency under full-load conditions.

A. B. C. D.

2.24 kw 2.44 kw 2.64 kw 2.84 kw

A household refrigerator that has a power input of 450 watts and a COP of 2.5 is to cool five large watermelons, 10 kg each, to 0 degC . If the watermelons are initially at 20 deg c, determine how long will take for the refrigerator to cool them. The watermelons can be treated as water whose specific heat is 4.2 kj/kg-K.

A. B. C. D.

2220 seconds 2230 seconds 2240 seconds 2250 seconds

When a man returns to his wall-sealed house on a summer day, he finds that the house is at 32 degC. He returns on the air conditioner which cools the entire house to 20deg C in 15mins. If COP is 2.5, determine the power drawn by the air conditioner. Assume the entire mass within the house is 800kg of air for which cv = 0.72 kj/kg-K, cp = 1.0 kj/kg-K.

A. B. C. D.

1.072 kw 2.072 kw 3.072 kw 4.072 kw

A heat source is 800K losses 2000 of heat to a sink at 500K. Determine the entropy generated during this process.

A. B. C. D.

1.5 kj/k 2.5 kj/k -2.5 kh/k 4 kj/k

Helium gases is compressed in an adiabatic compressor from an initial state of 14 psia and 50F to a final temperature of 320F in a reversible manner. Determine the exit pressure of helium.

A. B. C. D.

38.5 psia 40.5 psia 42.5 psia 44.5 psia

Air pass thru a nozzle with efficiency of 90%. The velocity of air at the exit is 600 m/s. find the actual velocity at the exit.

A. B. C. D.

382 m/s 540 m/s 458 m/s 568 m/s

A 50 kg block of iron casting at 500K is thrown into a large lake that is at a temperature of 258K. The iron block eventually reaches thermal equilibrium with the lake water. Assuming average specific heat of 0.45 kj/kg-k for the iron, determine the entropy generated during this process.

A. B. C. D.

-12.65 kj/K 16.97 kj/k 4.32 kj/k 6.32 kj/k

A windmill with a 12 m diameter rotor is to be installed at a location where the wind is blowing at an average velocity of 10 m/s. using standard condition of air ( 1atm, 25 deg C), determine the maximum power that can be generated by the windmill.

A. B. C. D.

68 kw 74 kw 72 kw 70 kw

Consider a large furnace that can supply heat at a temperature of 2000 degR at a steady rate of 3000 btu/s. determine the energy? Assume an environment temperature of 77K.

A. B. C. D.

2305.19 kw 2315.19 kw 2325.19 kw 2335.19 kw

A heat engine receives heat from a source at 1200 degK at a rate of 500 kj/s and rejects the waste heat to a medium at 300 degK. The power output of the heat engine is 180 kw. Determine the irreversibility rate for this process.

A. B. C. D.

190 kw 195 kw 200 kw 205 kw

A dealer advertises that he has just received a shipment of electric resistance heaters for residential buildings that have an efficiency of 100%. Assuming an indoor temperature of 21 degC and outdoor temperature of 10 degC, determine the second law efficiency of these heaters.

A. B. C. D.

8.74 % 6.74 % 3.74 % 4.74%

A thermal power plant has a heat rate of 11,363 btu/kw-hr. find the thermal efficiency of the plant.

A. B. C. D.

34% 30% 26% 24%

A rigid tank contains 2 kmol of N2 and 6 kmol of CO2, gases at 300 deg K and 115 mpa. Find the tank volume using ideal gas equation.

A. B. C. D.

7.33 m3 5.33 m3 3.33 m3 1.33 m 3

A spherical balloon with a diameter of 6 m is filled with helium at 20 deg C and 200 kpa. Determine the mole number.

A. B. C. D.

9.28 kmol 10.28 kmol 11.28 kmol 13.28 kmol

The air in an automobile tire with a volume of 0.53 ft3 is at 90degF and 20 psig. Determine the amount of air that must be added to raise the pressure to the recommended value of 80psig. Assume the atmospheric pressure to be 14.7 psia and the temperature and the volume to remain constant.

A. B. C. D.

0.026 lb 0.046 lb 0.066 lb 0.086 lb

A rigid tank contains 20 lbm of air at 20 psia and 70 deg F. more air is added to the tank until the pressure and temperature rise to 35 psia and 90 deg F, respectively. Determine the amount of air added to the tank.

A. B. C. D.

11.73 lb 13.73 lb 15.73 lb 17.73 lb

A rigid tank contains 5 kg of an ideal gas at 4 atm and 40 deg C. now a valve is opened, and half of mass of the gas is allowed to escape. If the final pressure in the tank is 1.5 atm, the final temperature in the tank is:

A. B. C. D.

-38 deg C -30 deg C 40 deg C 53 deg C

The pressure of an automobile tire is measured to be 200 kpa (gage) before the trip and 220 kpa (gage) after the trip at a location where the atmospheric pressure is 90 kpa. If the temperature of the air in the tire before the trip is 25 deg C, the air temperature after the trip is:

A. B. C. D.

45.6 deg C 54.8 deg C 27.5 deg C 26.7 deg C

Water is boiling at 1 atm pressure in a stainless pan on an electric range. It is observed that 2 kg of liquid water evaporates in 30 min. the rate of heat transfer to the water is:

A. B. C. D.

2.97 kw 0.47 kw 2.51 kw 3.12 kw

Consider, a person standing in a breezy room at 20 deg C. determine the total rate transfer from this person of the exposed surface area and the average outer surface temperature of the person are 1.6 m2 and 29 deg C, respectively, and the convection heat transfer coefficient is 6 w/m2 with emissivity of 0.95.

A. B. C. D.

86.40 watts 81.70 watts 198.1 watts 168.1 watts

Water is boiler in a pan on a stove at sea level. During 10 mins of boiling, it is observed that 200 grams of water has evaporated. Then the rate of heat transfer to the water is:

A. B. C. D.

0.84 kj/min 45.1 kj/min 41.8 kj/min 53.5 kj/min

An aluminum pan whose thermal conductivity is 237 w/m-C has a flat bottom whose diameter is 20 cm and thickness 0.4 cm. heat is transferred to boiling water in the pan through its bottom at a rate of 500 watts. If the inner surface of the bottom of the pan is 105 deg C, determine the temperature of the surface of the bottom of the pan.

A. B. C. D.

95. 27 deg C 105.27 deg C 115.27 deg C 125.27 deg C

For heat transfer purposes, a standing man can be modeled as a 30 cm diameter, 170 cm long vertical cylinder with bottom both the top and bottom surfaces insulated and with the side surface at an average temperature of 34 deg C. for a convection heat transfer coefficient heat loss from this man by convection in an environment at 20 deg C.

A. B. C. D.

316.46 watts 326.46 watts 336.46 watts 346.46 watts

A 5 cm diameter spherical ball whose surface is maintained at a temperature of 70 deg C is suspended in the middle of a room at 20 deg c. if the convection heat transfer coefficient is 15 N/m2C and the emissivity of the surface is 0.8, determine the total heat transfer from the ball.

A. B. C. D.

23.56 watts 32.77 watts 9.22 watts 43.45 watts

A frictionless piston-cylinder device and a rigid tank contain 1.2 kmol of a ideal gas at the same temperature, pressure, and volume. Now heat is transferred and the temperature of both system is raised by 15 deg C. the amount of extra heat that must be supplied to the gas in the cylinder that is maintained at constant pressure.

A. B. C. D.

0 50 kj 100 kj 150 kj

A supply 50 kg chicken at 6 deg C contained in a box is to be frozen to -13 deg C in a freezer. Determine the amount of heat that needs to be removed. The latent heat of the chicken is 247 kj/kg, and its specific heat is 3.32 kj/kg-C above freezing and 1.77 kj/kg-C below freezing. The container box is 1.5 kg and the specific heat of the box material is 1.4 kj/kg-C. also the freezing temperature of chicken is -2.4 deg C.

A. B. C. D.

15,206.4 kj 50.4 kj 15,156 kj 1,863 kj

Water is being in a closed pan on top of a range while being stirred by a paddle wheel. During the process, 30 kj of heat is transferred to the water, and 5 kj of heat is lost to the surrounding air. The paddle-wheel work amounts to 560 N-m. determine the final energy of the system if its initial energy is 10 kj.

A. B. C. D.

35.5 kj 45.5 kj 25.5 kj 14.5 kj

A classroom that normally contains 40 people is to be air-conditioned with window air-conditioning units of 5 km cooling capacity. A person at rest mat be assumed to dissipate heat at a rate of about 360 kj/hr. these are 10 light bulbs in the room, each with a rating of 100 watts. The rate of heat transfer to the classroom through the temperature of 21 deg C, determine the number of window air-conditioning units required.

A. B. C. D.

1 unit 2 units 3 units 4 units

A 4m x 5m x 6m room is to be heated by a baseboard resistance wear. It is desired that the resistance heater be able to raise the air temperature in the room from 7 to 23 deg C within 15 mins. Assuming no heat losses from the room and an atmoshperic pressure of 100 kpa, resistance heater. Assume constant specific heats at room temperaute.

A. B. C. D.

2.34 kw 1.91 kw 4.56 kw 6.34 kw

A student living in a 4m x 6m x 6m dormitory room turns on her 150watts fan before she leaves the room on a summer day, hoping that the room will be cooler when she comes back in the evening. Assuming all the doors and window are tightly closed and disregarding any heat transfer through the walls and the windows, determine the temperature in the room when she comes back 10hours later. Use specific heat value at room temperature, and assume the room to be at 100 kpa and 15 deg C in the morning whe she leaves.

A. B. C. D.

28.13 deg C 38.13 deg C 48.13 deg C 58.13 deg C

A piston cylinder device whose piston is resisting on top of a set of stops initially contains 0.50 kg of helium gas at 100kpa and 25 deg c . The mass of the piston is such that 500 kpa of pressure is required to raise it . How much heat must be transferred to the helium before the piston starts rising?

A. B. C. D.

1557.13 kj 1657.13 kj 1757.13 kj 1857.13 kj

In order to cool 1 ton (1000 kg) of water at 20 deg C in an insulated tank, a person pours 80 kg of ice at -5 deg C into the water. Determine the final equilibrium temperature in the tank. The melting temperature and the heat of fusion of ice at atmospheric pressure are 0 deg C and 333.7 kj/kg respectively.

A. B. C. D.

12.43 deg C 14.43 deg C 16.43 deg C 18.43 deg C

A fan is powered by a 0.5 hp motor and delivers air at a rate of 85 m3/min . Determine the highest value for the average velocity of air mobilized by the fan. Take the density of air to be 1.10 kg/m3.

A. B. C. D.

10.23 m/s 21.12 m/s 25.34 m/s 32.23 m/s

Ocean thermal energy conversion power plant generates 10,000 kw using a warm surface water inlet temperature of 26 deg C and a cold deep-water temperature of 15 deg C. on the basis of a 3 deg C drop in the temperature of the warm water and a 3 deg C rise in the temperature of the cold water due to removal and addition of heat, calculate the power required in kw to pump the cold-deep water to the surface and through the system heat exchanger if the required pumping pressure increase is 12 kpa. Assume a carnot cycle efficiency and density of cold water to be 1000 kg/m3

A. B. C. D.

108 160 145 250

A plate-type solar energy collector with an absorbing surface covered by a glass plate is to receive an incident radiation of 800 w/m2 . The glass plated transmissivity of 0.85. the absorbing surface has an absorptivity of 0.90. the area of the collector is 5 m2. how much solar energy in watts is absorbed by the collector?

A. B. C. D.

2500 3060 3510 2880

An elastic sphere containing gas at 120 kpa has a diameter of 1.0 m . Heating the sphere causes it to expand to a diameter of 1.3 m . During the process the pressure is proportional to the sphere diameter. Calculate the work done by the gas in kj.

A. B. C. D.

41.8 50.6 87.5 35.4

A tank contains liquid nitrogen at -190 deg C is suspected in a vacuum shell by three stainless steel rods 0.80 cm in diameter and 3 meters long with a thermal conductivity of 16.3 w/m2-deg C . If the ambient air outside the vacuum shell is 15 deg C , calculate the magnitude of the conductive heat flow in watts along the support rods.

A. B. C. D.

0.168 0.176 0.182 0.0587

An ideal gas with molecular weight of 7.1 kg/kg mol is compressed from 600 kpa and 280 deg K to a final specific volume of 0.5 m3/kg . Calculate the work of compression in kj/kg?

A. B. C. D.

32.8 33.3 35.6 28.7

A one cubic container contains a mixture of gases composed of 0.02 kg-mol of oxygen and 0.04 kgmol of helium at a pressure of 220 kpa. What is the temperature of this ideal gas mixture in degrees kelvin?

A. B. C. D.

441 450 400 350

Methyl alcohol (CH3OH) is burned with 25% excess air. How much unburned oxygen in kg-moloxygen/kg-mol-fuel will there in the products if the combustion is complete?

A. B. C. D.

0.35 0.45 0.37 0.65

A 12 DC electrical motor draws a current of 15 apms. How much work in kj does this motor produce over a 10-minute period of operation?

A. B. C. D.

108.0 318.2 216.0 129.6

A 4 liter ( 2-liter per revolution at standard pressure and temperature ) spark ignition engine has a compression ratio of 8 and 2200 kj/kg heat addition by the fluid combustion. Considering a by the fluid combustion. Considering a cold air-standard otto cycle model, how much power will the engine produce when operating at 2500 rpm?

A. B. C. D.

166.53 hp 73.12 hp 97.4 hp 148 hp

A simper rankine cycle produces 40 MW of power, 50 MW of process heated and rejects 50 MW of heat to the surroundings. What is the utilization factor of this cogeneration cycle neglecting the pump work?

A. B. C. D.

50% 80% 64% 60%

The rate of heat transfer to the surroundings from a person at rest is about 400 kj/hr . Suppose that the ventilation system fails in an auditorium containing 120 people and assuming that the energy goes into the air of volume 1500 m3 initially at 300 deg K and 101 kpa, calculate the rate in deg c/min of air temperature change.

A. B. C. D.

0.81 0.53 0.63 1

An insulated box containing helium gas falls from a balloon 4.5 km above the earth’s surface. Calculate the temperature rise in deg C of the helium when box hits the ground.

A. B. C. D.

15.2 14.1 25.3 12.6

Consider two carnot heat engines operating in series. The first engine receives heat from the reservoir at 2400 deg K and rejects the waste heat to another reservoir at temperature T. the second engine receives heat by the first one, convert some of it to work, and rejects the rest to a reservoir at 300 deg K . If thermal efficiencies of both engines are the same, determine the temperature T.

A. B. C. D.

849 deg K 578 deg K 763 deg K 978 deg K

An ideal gas mixture consists of 2kmol of n2 and 6 kmol of CO2. the apparent gas constant of mixture is:

A. B. C. D.

0.208 0.825 0.531 0.231

An ideal gas mixture consists of 2 kmol of n2 and 6 kmol of CO2. the mass fraction of CO2 is:

A. B. C. D.

0.175 0.250 0.825 0.750

A carnot cycle operates between the temperature limits of 300 deg K and 1500 deg K, and produces 600 kw of net power. The rate of entropy change of the working fluid during the heat addition process is:

A. B. C. D.

0 0.4 kw/k 0.5 kw/k 2.0 kw/k

Air in an ideal diesel cycle is compressed from 3 to 0.15 and then it expands during the constant pressure heat addition process to 0.3 h, under cold air standard conditions, the thermal efficiency of this cycle is:

A. B. C. D.

35% 65% 70% 44%

Helium gas in an ideal otto cycle is compressed from 20 deg C and 2 h to 0.25 L and its temperature increases by an additional 800 deg C during the heat addition process. The temperature of helium before the expansion process is :

A. B. C. D.

1700 C 1240 C 1440 C 880 C

In an ideal otto cycle, air is compressed from 1.20 kg/m3 and 2.2 L to 0.26 L and the net work output of the cycle is 440 kj/kg. the mean effective pressure for the cycle is:

A. B. C. D.

612 kpa 528 kpa 599 kpa 416 kpa

An ideal brayton cycle has a net work output of 150 kj/kg and backwork of 0.4. if both the turbine and the compressor had an isentropic efficiency of 80%, the net work putput of the cycle would be:

A. B. C. D.

50 kj/kg 75 kj/kg 98 kj/kg 120 kj/kg

Air enters a turbojet engine at 200 m/s at a rate of 20 kg/s, and exits at 800 m/s relative to the aircraft. The thrust developed by the engine is:

A. B. C. D.

6 kn 16 kn 20 kn 12 kn

A thermal power has a net power 10 MW the backwork ratio of the plant is 0.005. determine the compressor work.

A. B. C. D.

50.15 KW 50.35 KW 50.25 KW 50.45 KW

A heat engine receives heat from a source at 1200 deg F at a rate of 500 kj/s2 and rejects the waste heat to a sink at 300 deg K. if the power output of the engine is 200 KW, the second law efficiency of this heat engine is:

A. B. C. D.

35% 53% 75% 40%

A water reservoir contains 100,000 kg of water at an average elevation of 60 m . The maximum amount of electric power that can be generated from this water is:

A. B. C. D.

8 KWh 1630 KWh 16 KWh 58,800 KWh

A house is maintained at 22 deg C in winter by electric resistance heaters. If the outdoor temperature is 5 deg C, the second law efficiency of the resistance heaters is :

A. B. C. D.

0% 34% 77% 5.8%

A thermoelectric refrigerator that resembles a small ice chest is powered by a car battery, and has a COP of 0.10. if the refrigerator cools a 0.350 L canned drink from 20 deg C to 40 deg C . In 30 min, determine the average electric power consumed by the thermoelectric refrigerator.

A. B. C. D.

130 W 120 W 110 W 140 W

The refrigerant volume flow rate at the entrance of compressor were obtain from a test on a twist cylinder, single acting 15cm x 20cm, 320rpm compressor ammonia refrigerating a plant to be 33 liters/sec. determine the volumetric efficiency of the compressor.

A. B. C. D.

77.65 % 87.60 % 97.60 TR 65.65 %

Compute the humidity ratio of air at 70% relative humidity and 25 degrees C when the barometric pressure is 101.325 kpa from steam tables. Psat at 34 deg C = 3.169 kpa.

A. B. C. D.

0.014 kg water vapor / kg dry air 0.14 kg water vapor / kg dry air 1.4 kg water vapor / kg dry air 0.0014 kg water / kg dry air

A pressure gage registers 50 psig in a region where the barometer reads 14.8 psia find the absolute pressure in kpa.

A. B. C. D.

666.66 kpa 556.66 kpa 446.66 kpa 336.66 kpa

Consider 1 kg of air at 32 deg C that expanded by a reversible polytropic process with n = 1.25 until the pressure is halved. Determine the heat transfer.specific heat at constant volume for air is 0.1786 kj/kg-k.

A. B. C. D.

17.02 kj heat rejected 17.02 kj heat added 7.05 kj heat rejected 7.05 kj heat added

50 kg of cooling water per second enter the condenser at 25 deg C and leaves at 50 deg C find the heat carried away by water.

A. B. C. D.

1,234.45 kw 5,233.75 kw 2,340.53 kw 3,140.25 kw

10 kg per seconds of steam enter the turbine with an enthalpy of 3200 kj/kg and enter the condenser with an enthalpy 2500 kj/kg in a Rankine cycle. If the turbine efficiency 80% and generator efficiency 90%. Determine the power plant output.

A. B. C. D.

4,320 kw 3,213 kw 4,056 kw 5,040 kw

Determine the quality of steam in a vessel containing 2 kg of saturated vapor and 8 kg of saturated liquid.

A. B. C. D.

100 % 20 % 80 % 60 %

The condenser of a reheat power plant rejects heat at a rate of 600 kw. the mass flow rate of a cooling water is 5 kg per second and the inlet cooling water temperature is 35 deg C. calculate the condenser cooling water exit temperature.

A. B. C. D.

43.45 deg C 53.45 deg C 63.66 deg C 74.34 deg C

A heat engine has a thermal efficiency of 50 %. How much power does the engine produce when heat is transferred at a rate of 109 kj/hr.

A. B. C. D.

50 MW 75 MW 139 MW 147 MW

1 kg of air is compressed adiabatically and in a steady flow manner. The compression efficiency is 80 % the work done on the air is 265 kj/kg. compute the heat.

A. B. C. D.

212 kj/kg 100 kj/kg 0 331.25 kj/kg

300 kj of heat flow by conduction from the outside to the inside of a cold storage in 1 hour if the temperature and all other conditions are the same. What is the heat flowing? through the cold storage room in 2 hours.

A. B. C. D.

600 kj 900 kj 300 kj 1200 kj

Determine the specific weight of air at 760 mm Hg absolute and 22 deg C.

A. B. C. D.

1.024 kg/m3 1.316 kg/m3 1.197 kg/m3 1.266 kg/m3

Find the enthalpy of helium if its internal energy is 200 kj/ kg.

A. B. C. D.

144 kj/kg 223.42 kj/kg 333.42 kj/kg 166 kj/kg

Compute the mass of 2m3 propane at 280 kpa and 40 deg C.

A. B. C. D.

6.47 kg 5.1 kg 10.20 kg 9.47 kg

Compute the air flow in ft3/min of mechanical ventilation required to exhaust an accumulation of refrigerant due to leaks of the system capable of revolving air from the machinery room for a mass of 4 kg refrigerant.

A. B. C. D.

200 210 220 230

Compute the free - aperture cross – section in meter2 for the ventilation of a machinery room if the mass of refrigerant is 9 kg.

A. B. C. D.

0.314 0.414 0.514 0.614

A 29.53 in x 39.37 in pressure vessel contains ammonia with f = 0.041. compute the minimum required discharge capacity of the relief device in kg/hr.

A. B. C. D.

106.71 kg/hr 108.71 kg/hr 110.71 kg/hr 112.71 kg/hr

Compute the maximum length of the discharge pipe installed on the outlet of a pressure relief device in ft for internal pipe diameter of 0.5 in. and rated discharge capacity is 8 lb/min of air. The rated pressure relief valve is 16 psig.

A. B. C. D.

0.286 ft 0.386 ft 0.486 ft 0.586 ft

A thermal power plant has a heat rate of 11,363 Btu/kw-hr. find the thermal efficiency of the plant.

A. B. C. D.

28 % 30 % 34% 40 %

Find the loss of head in the pipe entrance if speed of flow is 10m/s.

A. B. C. D.

5.10 m 10.2 m 17.4 m 2.55 m

Wet material containing 220 % moisture (dry basis) is to be dried at the rate of 1.5 kg/s in a continuous drier to give a product containing 10% ( dry basis). Find the moisture remove kg/hr.

A. B. C. D.

3543.75 kg/hr 3513.75 kg/hr 3563.75 kg/hr 3563.75 kg/hr

Copra enters a drier containing 70% moisture and leaves at 7 % moisture. Find the moisture remove on each pound of solid in final product.

A. B. C. D.

6.258 lb 1.258 lb 4.258 lb 2.258 lb

A 1m x 1.5m cylindrical tank is full of oil with SG = 0.92. find the force acting at the bottom of the tank and dynes.

A. B. C. D.

106.33 x 107 dynes 106.33 x 104 dynes 106.33 x 105 dynes 106.33 x 106 dynes

Find the pressure at 100 fathom depth of water kpag.

A. B. C. D.

1,793.96 kpag 1,893.96 kpag 1,983.96 kpag 1,693.96 kpag

Find the depth in furlong of the ocean ( Sg = 1.03) if the pressure at the sea bed is 2032.56 kpag.

A. B. C. D.

1 2 3 4

Find the mass of ten quartz of water.

A. B. C. D.

10.46 kg 9.46 kg 11.46 kg 8.46 kg

Find the mass of carbon dioxide having a pressure 20 psia at 200 deg F with 10 ft3 volume.

A. B. C. D.

1.04 lbs 1.14 lbs 1.24 lbs 1.34 lbs

Find the heat needed to raise the temperature of water from 30 deg C to 100 deg C with 60 % quality. Consider an atmospheric pressure of 101.325 kpa use the approximate enthalpy formula of liquid.

A. B. C. D.

293.09 kj/kg 1773.90 kj/kg 1547.90 kj/kg 1647.29 kj/kg

An air compressor consumed 1,200 kw-hr per day of energy the electric motor driving the compressor has an efficiency of 80 %. If the indicated power of the compressor is 34 kw, find the mechanical efficiency of the compressor.

A. B. C. D.

117.65 % 75 % 85 % 90 %

A refrigeration system consumed 28,800 kw-hr per month of energy. There are 20 % energy is loss due to cooling system of compressor and motor efficiency is 90 %. If COP of the system is 6, find the tons of refrigeration of the system.

A. B. C. D.

43.15 TR 46.15 TR 49.15 TR 41.15 TR

A 23 tons of refrigeration system has a heat rejected of 100 kw . Find the energy efficiency ratio of the system.

A. B. C. D.

13.42 14.42 15.42 16.42

A 200 mm x 250 mm, 8-cylinder , 4-stroke diesel engine has a brake power of 150 kw. The mechanical efficiency is 80 %. If two of the cylinders were accidentally cut-off, what will be the new friction power?

A. B. C. D.

31.50 kw 33.50 kw 35.50 kw 37.50 kw

If the energy efficiency ratio of the refrigeration system is 12.6, what is the COP of the system.

A. B. C. D.

3.69 4.23 5.92 6.83

An air compressor has a power of 40 kw at 4 % clearance. If clearance will increase to 7% what is the new power?

A. B. C. D.

70 kw 40 kw 53 kw 60 kw

What is the approximate value of temperature of water having enthalpy of 208 BTU/lb .

A. B. C. D.

138.67 deg C 115.55 deg C 258.67 deg C 68.67 deg C

An otto cycle has a compression ratio of 8. find the pressure ratio? During compression.

A. B. C. D.

18.38 16.38 14.38 12.38

A diesel cycle has cut-off ratio of 2.5 and the expansion ratio of 4. find the clearance of the cycle.

A. B. C. D.

9.11 % 5.55 % 11.11 % 15.15 %

A dual cycle has an initial temperature 30 deg C. the compression ratio is 6 and the heat addition at constant volume process is 600 kj/kg. if cut-off ratio is 2.5. find the maximum temperature of the cycle.

A. B. C. D.

3638.50 deg C 3365.50 deg C 3565.50 deg C 3965.50 deg C

A 10-stage air compressor air from 100 kpa to 800 kpa. Find the intercooler pressure between the 1st and 2nd stage.

A. B. C. D.

282.84 kpa 113.25 kpa 123.11 kpa 333.51 kpa

A three-stage air compressor air from 100 kpa to 1000 kpa find the intercooler pressure between 1st and 2nd stage?

A. B. C. D.

505.44 kpa 108.44 kpa 316.23 kpa 215.44 kpa

A 3-stage air compressor compresses air from 100 kpa to 700 kpa. Find the intercooler pressure between 2nd and 3rd stage.

A. B. C. D.

365.88 kpa 375.88 kpa 385.88 kpa 395.88 kpa

Carnot cycle A, B and C are connected in series so that the heat rejected from A will be the heat added to B and heat rejected from B will be added to C, each cycle operates between 30 deg C to 400 deg C. if heat added to A is 1000 kw , find the work output of C.

A. B. C. D.

111.44 kw 549.78 kw 247.53 kw 141.69 kw

2 kg of air in a rigid tank changes its temperature from 32 deg C to 150 deg C. find the work done during the process?

A. B. C. D.

236 170 195 0

Determine the atmospheric pressure at a location where barometric reading is 740 mm Hg and gravitational acceleration is g = 9.7 m / s2. Assume the temperature of mercury to be 10˚C, at which the density is 13,670 kg / m3 . A. 99.45 kPa B. 97.41 kPa C. 95.44 kPa D. 98.66 kPa

The barometer of a mountain hiker reads 930 mbars at the beginning of a hiking trip and 780 mbars at the end. Neglecting the effect of altitude on local gravitational acceleration. Determine the vertical distance climbed. Assuming g = 9.7 m / s2 A. 1274.21 m B. 1289.00 m C. 1267.34 m D. 1583.34 m

The lower half of a 10 m high cylindrical container is filled with water and the upper half with oil that has SG = 0.85. Determine the pressure difference between the top and bottom of the cylinder. a. b. c. d.

90.74 92.74 83.38 96.10

kPa kPa kPa kPa

An ideal gas at 0.80 atmospheres and 87o C, 0.45 liter. How many moles are in the sample? (R = 0.0821 liters-atm/mole-K a. b. c. d.

0.0002 0.0378 0.0122 0.0091

mole mole mole mole

A certain gas at 101.325 kPa and 10o C whose volume is 2.83 m3 are compressed into a storage vessel at 0.31 m3 capacity. Before admission, the storage vessel contained the gas at a pressure and temperature of 137.8 kPa and 26o C after admission the pressure has increased to 1171.6 kPa. What should be the final temperature of the gas in the vessel in Kelvin a. 296.0 b. 319.8 c. 180.0 d. 314.2

A perfect gas has a value of R = 58.8 ftlb/lb-oR and k = 1.26. if 20 BTU are added to 10 lbs of the gas at constant volume when initial temperature is 90o F. Find the final temperature. a. b. c. d.

97oF 104oF 154oF 185oF

Ammonia weighing 22 kg is confirmed inside a cylinder equipped with a piston has an initial pressure of 413 kPa at 38o C. If 3200 kJ of heat is added to the ammonia until its final pressure and temperature are 413 kPa at 100o C, respectively, what is then amount of work done by the fluid in kJ? a. 667 b. 304 c. 420 d. 502

A tank contains 90 ft3 of air at a pressure of 350 psig. If the aire is cooled until its pressure and temperature decreases to 200 psig and 70oF, what is the decrease in internal energy? a. b. c. d.

6232.09 BTU -5552 BTU 5552 BTU -6232.09 BTU

A large mining company was provided with a 3 m3 of compressed air tank. Air pressure in the tank drops from 700 kPa to 150 kPa while the temperature remains constant at 28oC. What percentage has the mass of air in the tank been reduced? a. b. c. d.

74.00 72.45 78.56 78.57

A 4 m3/hr pump delivers water to a pressure tank. At the start, the gage reads 138 kPa until it reads 276 kPa and then the pump was shut off. The volume of the tank is 180 liters. At 276 kPa the water occupied 2/3 of the tank volume. Determine the volume of water that can be taken out until the gage reads 138 kPa. a. 31.20 liters b. 34.59 liters c. 16.67 liters d. 29.50 liters

A refrigeration plant is rated at 15 tons capacity. Howz many pounds of air per hour will it cool from 70 to 90oF at constant pressure.

a. b. c. d.

50,000 37,500 52,000 45,000

lb/hr lb/hr lb/hr lb/hr

Determine th air – standard efficiency of an engine operating on the diesel cycle with clearance of 6% when the suction pressure is 99.97 kPa and the fuel is injected for 7% of the stroke. Assume k = 1.4 a. b. c. d.

62.11% 51.20% 73.58% 60.02%

Steam at 2 Mpa and 250oC in a rigid cylinder is cooled until the quality is 30%. Find the heat rejected from the cylinder: at 2 Mpa and 250oC v = 0.11144 m3/kg u = 2679.6 kJ/kg. At 2 Mpa (saturated,) vf = 0.0011767 m3/kg vg = 0.0011767 0.09963 m3/kg uf = 906.44 ug = 1693.8 a. b. c. d.

-432.23 kJ/kg -926.26 kJ/kg -1265.02 kJ/kg 1082.34 kJ/kg

At 1.3 MPa, mixture steam and water has an entropy of 3 kJ/kg-oK. Find the enthalpy of the mixture: at 1.3 MPa sf = 2.2525 sg = 6.4953 hf = 814.93 hg = 1972.7 a. b. c. d.

1627.71 1533.33 1234.45 1162.40

kJ/kg kJ/kg kJ/kg kJ/kg

Mixture with 70% quality at 500 kPa is heated isothermally until its pressure is 300 kPa. Find the heat added during the process: at 500 kPa sf = 1.8607 sfg = 4.9606 at 300 kPa and 151.86oC cs = 7.0888 a. b. c. d.

745.92 535.16 983.44 765.34

kJ/kg kJ/kg kJ/kg kJ/kg

A tank contains exactly one kilograms of water consisting of liquid and vapor in equilibrium at 1 Mpa. If the liquid contains one – third and the remaining is the enthalpy of the contents of the tank? At 1 MPa: vf = 0.0011273 vfg = 0.19444 hf = 762.81 hfg = 2015.4 a. b. c. d.

644.40 kJ/kg 774.40kJ/kg 785.92 kJ/kg 485.29 kJ/kg

Water substance at 70 bar and 65oC enters a boiler tube at constant inside diamete of 35 mm. The water leaves the boiler tube at 50 bar and 700oK at velocity of 100 m/s. Calculate the inlet volume flow (L/s) From steam tables: at 70 bar (7MPa) at 65oC v1 = 0.001017 m3/kg at 50 bar (5MPa) and o 700 K (427oC) v2 = 0.06081 m3/kg a. 0.821 b. 1.261 c. 0.344 d. 1.609

Water substance at 70 bar and 65oC enters a boiler tube at constant inside diamete of 25 mm. The water leaves the boiler tube at 50 bar and 700oK at velocity of 150 m/s. Calculate the inlet vELOCITY (m/s) From steam tables: at 70 bar (7MPa) at 65oC v1 = 0.001017 m3/kg at 50 bar (5MPa) and 700oK (427oC) v2 = 0.06081 m3/kg

a. b. c. d.

1.56 2.51 1.672 3.230

Steam leaves an industrial boiler at 827.4 kPa and 171.6 oC. A portion of the steam is passed through a throttling calorimeter and is exhausted to the atmosphere when the calorimeter pressure is 101.4 kPa. How much moisture does the steam leaving the boiler contain if the temperature of the steam at the calorimeter is 115.6 oC? At 827.4 kPa (171.6 oC) hf = 727.25 kJ/kg hfg = 2043.2 kJ/kg. From table 3: at 101.4 kPa and 115.6oC 3.78% ha. = 2707.6 kJ/kg 2

b. 3.08% c. 4.56% d. 2.34%

Atmospheric pressure boils at 212oF. At the vacuum pressure at 24 in Hg, the tempreature is 142oF. Find the boiling temperature when the pressure is increased by 40 psia from atmospheric. a. b. c. d.

449.42oF 526.34oF 479.13oF 263.45oF

A certain coal has the following ultimate analysis: C = 69% N2 = 5% H2 = 2.5% S = 7%. Determine the amount of oxygen if the heating value of fuel is 26,961.45 kJ/kg a. b. c. d.

1.5% 2.5% 3.5% 4.5%

A diesel engine consumed 645 liters of fuel per day at 35oC. If the fuel was purchased at 15.5oC and 30oAPI at P29.00/L, determine the cost of fuel to operate the engine per day. a. b. c. d.

P5677.50 P4577.50 P46,088.90 P27,127.76

A cylindrical tank 4 m long and 3 m diameter is used for oil storage. How many days can the tank supply the engine having 27oAPI with fuel consumption of 60 kg/hr a. b. c. d.

17.53 5.84 12.84 19.84

The dry exhaust gas from oil engine has the following fravimetric analysis: CO2 = 21.6% O2 = 4.2% N2 = 74.2% Specific heats at constant pressure for each component of the exhaust gas in kcal/kg-oC are CO2 = 0.203 O2 = 0.219 N2 = 0.248. calculate the specific gravity if the molecular weight of air is 28.97 kg/kg-mol a. 0.981 b. 1.244 c. 1.055 d. 0.542

A bituminous coal has the following composition: C = 71.5% H = 5.0% O = 7.0% N = 1.3% S = 3% Ash = 7.6% W = 3.4% Determine the theoretical weight of Nitrogen in lb/lb of coal. a. b. c. d.

2.870 7.526 2.274 6.233

A gaseous fuel mixture has a molar analysis: H2 = 14% CH4 = 3% CO = 27% O2 = 0.6% CO2 = 4.5% N2 = 50.9% Determine the air – fuel ratio for complete combustion on molar basis. a. b. c. d.

2.130 3.230 1.233 1.130

A volumetric analysis of a gas mixture is as follows: CO2 = 12% O2 = 4% N2 = 82% CO = 4% What is the percentage of CO2 on a mass basis? a. b. c. d.

17.55% 15.55% 12.73% 19.73%

An impulse wheel at best produces 125 hp under a head of 210 ft. By what percent should the speed be increases for a 290 – ft head?

a. b. c. d.

82.5% 17.5% 72.41% 27.59%

Find the work posses for a helium gas at 20 deg C?

a. b. c. d.

609 168 229 339

kJ/kg kJ/kg kJ/kg kJ/kg

What is the hydraulic gradient of a 1 mile, 17 inches inside diameter pipe when 3300/min of water flow with f = 0.03

a. b. c. d.

0.00714 0.00614 0.00234 0.00187

Convert 750oR to oK.

a. b. c. d.

390.33oK 395.33oK 410.33oK 416.33oK

Air is compressed adiabatically from 30oC to 100oC. If mass of air being compressed is 5 kg. Find the change in entropy.

a. b. c. d.

1.039 kJ/kg 0.746 kJ/kg 0 1.245 kJ/kg

An air standard engine has a compression ratio of 18 and a cut – off ratio of 4. if the intake air piressure and temperature are 100 kPa and 27oC, find the work in kJ per kg. a. b. c. d.

2976 2166 1582 2751

A throttling calorimeter is connected to the desuperheated steam line supplying the steam to the auxiliary feed pump on a ship. The line pressure measures 2.5 MPa. The calorimeter pressure is 110 kPa and 150oC. Determine the entropy of the stea,m line. At 110 kPa and 150oC: h2 = 2775.6 kJ/kg At 2.5 Mpa: hf = 952.11 kJ/kg-K hfg = 1841 kJ/kg a. 6.8 kJ/kg-K b. 6.2 kJ/kg-k c. 6.6 kJ/kg-k d. 7.5 kJ/kg-k

A logging firm in Isabella operates a Diesel Electric Plant to supply its electric energy requirements. During a 24 hour period, the plant consumed 250 gallons of fuel at 80oF and produced 2900 kW-hr. Industrial fuel used is 30oAPI and was purchased at P30.00/L at 60oF. Determine the overall thermal efficiency of the plant.a a. 26.08% b. 34.23% c. 28.00% d. 18.46%

The following coal has the following ultimate analysis by weight: C = 70.5% H2 = 4.5% O2 = 6.0% N2 = 1.0% S = 3.0% Ash = 11% Moisture = 4%. A stocker fired boiler of 195,000 kg/hr streaming capacity uses this coal as fuel. Calculate volume of air in m3/hr with air at 60oF and 14.7 psia pressure if boiler efficiency is 70% and FE 1.10. m3/hr a. = 234,019 b. 215,830 m3/hr c. 213,830 m3/hr d. 264,830 m3/hr

and 400 oC is produced by a steam generator. The feedwater enters the economizer at 145 oC and leaves at 205 oC. The steam leaves the boiler drum with a quality of 98%. The unit consumes 3 kg of coal per second as received having a heating value of 25,102 KJ/kg. What would be the overall efficiency of the unit in percent? Steam properties: At 5 Mpa and 400 oC : h = 3195.7 KJ/kg At 5 Mpa: hf = 1154.23, hfg = 1640.1 o 65. Ata. 205 C :72 hf = 875.04 At 145 oC : hf = 610.63

b. 80. 67 c. 88.28 d. 78.82

turbines at 2.5 MPa (enthalpies and entropies given) and condenser of 50 kPa (properties given), what is the thermal efficiency of the cycle? At 2.5 Mpa : hg = 2803.1 KJ/kg Sg = 6.2575 At 50 kPa : Sf = 1.0910 Sfg = 6.5029 hf = 340.49 hfg = 2305.4 Vf = a. 25. 55 % 0.0010300 b. 45. 23 % c. 34. 23 % d. 12. 34 %

A thermal power plant generates 5 MW and the heat generated by fuel is 13, 000 KJ/sec. If thermal efficiency is 36.15%, find the power needed for the auxiliaries. a. b. c. d.

310 300 400 350

kW kW kW kW

A superheat steam Rankine cycle has turbine inlet conditions of 17.5 Mpa and 530 oC expands in a turbine to 0.007 Mpa. The turbine and pump polytropic efficiencies are 0.85 and 0.75 respectively, pressure losses between pump and turbine inlet are 1.5 Mpa. What should be the pump work a. 17. in 34KJ/kg? b. 27. 32 c. 25. 32 d. 47. 33

In an open feedwater heater for a steam plant, saturated steam at 7 bar is mixed with subcooled liquid at 7 bar and 25 oC. Just enough steam is supplied to ensure that the mixed steam leaving the heater will be saturated liquid at 7 bar when heater efficiency is 95%. Calculate the mass flowrate of subcooled liquid if steam flowrate is 0.865 kg/s. Steam properties are: At 7 bar, saturated vapor: hg = 2763.5 KJ/kg At 7 bar and 25 a. 2.725 kg/s b. 3.356 kg/s c. 2.869 kg/s d. 3.948 kg/s

A steam condenser receives 10 kg / s of steam with an enthalpy of 2770 kJ / kg. Steam condenses into a liquid and leaves with an enthalpy of 160 kJ / kg. Cooling water passes through the condenser with temperature increases from 13˚C to 24˚C. Calculate the water flow rate in kg / s. A. 583 B. 567 C. 523 D. 528

Steam expands adiabatically in a turbine from 2000 kPa, 400˚C to 400 kPa, 250˚C. What is the effectiveness of the process in percent assuming an atmospheric pressure of 18˚C. Neglect changes in kinetic and potencial energy. Steam properties are : @ 2000 kPa and 400˚C: h = 3247.6 kJ / kg , s = 7.1271 kJ / kg-K @ 400 kPa and 250˚C : h = 2964.2 kJ / kg , s = 7.3789 kJ / kg-K A. 82 B. 84 C. 79.60 D. 79.46

A heat exchanger was installed purposely to cool 0.50 kg of gas per second. Molecular weight is 32 and k = 1.32. The gas is cooled from 150˚C to 80˚C. Water is available at the rate of 0.30 at the rate of 0.30 kg / s and at a temperature of 15˚C. Calculate the exit temperature of the water in ˚C. A. 44.86 B. 42.86 C. 46.45 D. 40.34

A 350 mm x 450 mm steam engine running at 280 rpm has an entrance steam condition of 2 MPa and 230˚C and exit at 0.1 MPa. The steam consumption is 2000 kg / hr and mechanical efficiency is 85%. If indicated mean effective pressure is 600 kPa, determine brake thermal efficiency, at 2MPa and 230˚C (Table 3) : h1 = 2849.6 , s1 = 6.4423. @ 0.1 MPa : sf = 1.3026 , hf = 417.46 , sfg = 6.0568 , hfg = 2258 , hf2 = 417.46 kJ / kg. A. 23.34 B. 15.25 C. 14.16 D. 27.34

A steam turbine receives 5000 kg / hr of steam at 5 MPa and 400˚C and velocity of 30 m / s. It leaves the turbine at 0.006 MPa and 85% quality and velocity of 15 m / s. Radiation loss is 10,000 kJ / hr. Find the kW developed. At 5 MPa and 400˚C : h1 = 3195.7 kJ / kg , s1 = 6.6459 at 0.006 MPa : hf = 3195.7 kJ / kg : s1 = 6.6459 at 0.006 MPa : hf = 151.53 , hfg = 2415.9 A. 1273.29 B. 2173.29 C. 1373.60 D. 7231.29

A steam turbine with 85% stage efficiency receives steam at 7 MPa and 550˚C and exhausts as 20 kPa. Determine the turbine work. At 7 MPa and 550˚C : h1 = 3530.9 kJ / kg , s1 = 6.9486 at 20 kPa (0.020 MPa) : sf = 0.8320 , hf = 251.40 sfg = 7.0766 , hfg = 2358.3 A. 1,117 kJ / kg B. 1,132 kJ /kg C. 1,123.34 kJ / kg D. 1054.95 kJ / kg

A stem turbine with 80% stage efficiency receives steam at 7MPa and 550˚C and exhausts at 20 kPa. Determine the quality at exhaust. At 7 MPa. And 550˚C , h1 = 3530.9 kJ / kg , s1 = 6.9486 at 20 kPa (0.020 MPa) , sf = 0.8320 , hf = 251.40 A. 96.96% B. 76.34% C. 82.34% D. 91.69%

A 18,000 kW geothermal plant has a generator efficiency of 90% and 80%, respectively. If the quality after throttling is 20% and each well discharges 400,000 kg / hr , determine the number of wells are required to produce if the change of enthalpy at entrance and exit of turbine is 500 kJ / kg. A. 4 wells B. 2 wells C. 6 wells D. 8 wells

A liquid dominated geothermal plant with a single flash separator receives water at 204˚C. The separator pressure is 1.04 MPa. A direct contact condenser operates at 0.034 MPa. The turbine has a polytropic efficiency of 0.75. For a cycle output of 60 MW, what is the mass flow rate of the well – water in kg / s? At 204˚C : hf = 870.51 kJ / kg , at 1.04 MPa : hf = 770.38 , hfg = 2009.2 , hg = 2779.6 , sg = 6.5729 , at 0.034 MPa : hf = 301.4 , hfg = 2328.8 , sf = 0.9793 , sfg = 6.7463. A. 2,933 B. 2,100 C. 1,860 D. 2,444

An engine generator rated 9000kVA at 80% power factor, 3 phase, 4160 V has an efficiency of 90%. If over all plant efficiency is 28%, what is the heat generated by the fuel? A. 18,800 kW B. 28,800 kW C. 7,500 kW D. 25,714 kW

The indicated thermal efficiency of a two stroke diesel engine is 60%. If friction power is 15% of heat generated, determine the brake thermal efficiency of the engine. A. 43% B. 45% C. 36% D. 37%

A 305 mm x 457 mm, four stroke, single acting diesel engine is rated at 150 kW at 260 rpm. Fuel consumption at rated load is 0.56 kg / kW-hr with a heating value of 43,912 kJ / kg. Calculate the brake thermal efficiency. A. 10.53 % B. 27.45 % C. 14.64 % D. 18.23 %

If the average energy in the nuclear reactor is 200 MeV/fission, what is the power output reactor if there are 2.34x10^-19 fission per second?

A. 550 W

C. 370 MW

B. 120 W

D. 750 MW

A steam engine delivers 1000 kg/hr steam. The enthalpies at entrance and exit of the engine are 3000 KJ/kg and 400KJ/kg respectively, Calculate the brake power of the engine if the brake thermal eff’cy is 20%. A. 144.44 KW B. 200.45 KW

C. 254.34 KW D. 345.75 KW

4 kg air enters a turbine with enthalpy of 600 KJ and velocity of 250 m/s. The enthalpy at exit is 486 KJ and velocity of 170 m/s. What is the work develop if there is a heat loss of 10 KJ? A. 128.83 KJ B. 171.2 KJ

C. 80.2 KJ D. 28.3 KJ

Air flows in a duct @ pressure of 150 Kpa with a velocity of 200 m/s. The temperature of air is 310 K. Determine the isentropic stagnation temp.?

A. 320 B. 332

C. 341 D. 361

The cooling water leaves the condenser at 60 deg. C. The ambient air is at 35 deg. C DB and 28 deg. C WB. Determine the cooling tower eff’cy?

A. 41.67 B. 80

C. 78 D. 53.33

An engine operating in a Carnot Cycle between temp. of 500 deg. C and 30 deg. C produces 50 KJ of work. What change in entropy occurs during the heat rejection portion of the cycle?

A. 106.4 J/K B. 160.4 J/K

C. 120.5 J/K D. 102.5 J/K

Steam generator operating at 92% eff’cy leaves water at 15.6 deg C. while steam leaves the desuperheater at h=3,374.8 KJ/kg. Estimate the evaporation factor if the boiler consumes coal of calorific value 24,500 KJ/kg. A. 6.81 m B. 6.72 m

C. 8.21 m D. 7.21 m

Determine the mass of ice produce from water per day for the ff: conditions; water temp. 22 deg. C, tonnage of the unit 150 tons, operating temp. 22 deg. C tonnage of unit 150 tons operating temp. -5 deg. C and 28 deg. C, latent heat of ice 330 KJ/kg. A. 107,498 kg

C. 134,112 kg

B. 120,465 kg

D. 140,362 kg

An amount of 4000 BTU of heat is transferred from a reservoir at 800 deg. F to a reservoir at 200 deg. F. Find the entropy change of the system. A. 2.89 B. 3.24

C. 1.34 D. 3.21

Determine the net cycle heat rate of steam power plant with a gross cycle heat rate of 75% and the ratio of turbine output to net cycle work output is 1.11.

A. 83.25% B. 76.25%

C. 87.45% D. 80.76%

An elastic sphere containing gas at 120 Kpa has a diameter of 1.0 m. Heating the sphere causes it to expand to a diameter of 1.4 m. During the process the pressure is proportional to the sphere diameter. Calculate the work done by the gas.

A. 143.92 KJ C. 154.5 KJ B. 200.7 KJ D. 133.91 KJ

The heat pump has a performance factor of 8.0. If the heat pump is used as a refrigerator, what is the required horsepower per ton of refrigeration?

A. 0.942 B. 0.456

C. 0.765 D. 0.673

A steam turbine has an entrance enthalpy of 3000 KJ/kg in an exit enthalpy of 2000 KJ/kg. What is the stage eff’cy if the actual enthalpy after isentropic expansion is 2200 KJ/kg.

A. 82% B. 70%

C. 86% D. 80%

An engine supplied with steam at pressure 1.5 Mpa in temp. 250 deg. C, and pressure of the exhaust is 0.016 Mpa. Assuming isentropic expansion. Find the dryness fraction of the steam after expansion. Steam properties; At 1.5 Mpa, 250 deg. C: S=6.711 KJ/kg-K . At 0.016 Mpa; Sf= 0.772 KJ/kg-K, Sfg=7.231 KJ/kg-K. A. 0.8235 B. 0.8978

C. 0.7689 D. 0.7654

An air conditioning engineer has given the following data to be air conditioned: sensible heat gain 50,000 BTU/hr. Room latent heat gain 10,000 BTU/hr. Outside condition 50 deg F. Calculate the refrigeration tonnage required with 10% safety factor. A. 5.5 B. 3.5

C. 1.5 D. 6.5

A refrigeration system produces 20kg/hr of ice from water at 20 deg.C Find the tonnage of the unit?

A. 0.66 B. 0.55

C. 0.77 D. 0.88

In an air standard Brayton cycle, the compressor receives air at 101.325 Kpa , 21 deg. C and it leaves at 600 Kpa at the rate of 4 kg/s. Determine the turbine work if the temperature of the air entering the turbine is 1000 deg. C. A. 3000 KW B. 2701 KW

C. 2028 KW D. 3500 KW

The entrance and exit of enthalpies of a steam turbine are 4000 and 3000 KJ/kg respectively. What is the mass of steam entering the turbine if the generator power is 3 MW and generator eff’cy is 90%. A. 12,000 kg/hr B. 14,000 kg/hr

C. 17,000 kg/hr D. 24,000 kg/hr

A circular chip (k=150 W/m-K) with a diameter 10 mm and thickness 4 mm embedded in a circuit board. Its front surface is exposed to the flow of a coolant (h=250 W/m^2-K) with temperature of 10 deg. C, while its side in black surfaces are perfectly insulated. If at any point in the chip the temp. must not exceed 90 deg. C, What is the steady state heat dissipation of the chip?

A. 2.86 W B. 1.56 W

C. 2.01 W D. 1.74 W

A new temperature scale is to be used where freezing and boiling temp. of water is at 100 deg. N and 100 deg. N respectively. Calculate the absolute zero in deg. N?

A. -992.6 deg. N C. -995.6 deg. N B. -932.7 deg. N D. -932.4 deg. N

A 6 MW steam turbine generator power plant has a full-load steam rate of 8 kg/KW-hr. Assuming that no load steam consumption as 15% of full-load steam consumption, compute for the hourly steam consumption at 75% load, in kg/hr? A. 37,800 kg/hr B. 38,700 kg/hr

C. 30,780 kg/hr D. 30,870 kg/hr

Liquid propane is contained in a storage tank at a pressure of 1.4 Mpa, which is the equilibrium vapor pressure at the pumping conditions. The propane has a specific gravity of 0.58. If the level of the liquid propane is 4 m above the centerline of the pump and the frictional losses in the suction line is equal 2 m, What is the available NPHS if the velocity in the suction line is 1.50 m/s? A. 6.12 m B. 2 m

C. 4.12 m D. 2.12 m

The turbine power of a geothermal power plant is 2 MW and the enthalpy at the inlet of the turbine is 250 KJ/kg. Steam flows at the rate of 2.5 kg/s. If the enthalpy at the outlet of the condenser is 300 KJ/kg and the temp. rise of the cooling water is 10 deg. C. What is the volume flow rate of the cooling water? A. 109.37 m^3/hr B. 237.68m^3/hr

C. 120.37 m^3/hr D. 320.47m^3/hr

A rectangular duct 0.15 m by 0.12 cm long and carries standard air at the rate of 0.3 m^3/s. calculate the total pressure required at the inlet to the duct in order to maintain this flow. Assume that for the duct, the friction factor is 0.005.

A. 567.58 N/m^2 B. 671.85 N/m^2

C. 851.67 N/m^2 D. 716.58 N/m^2

Annual peak load on a 15,000KW power plant is 10,500KW. Two substation are supllied by this plant. Annual energy dispatched through substationA is 27,500,000 KW-Hr. with a peak load at 8900 KW, 16,500,000 are sent through substation B with a peak load at 6,650 KW. Neglect line losses. Find the diversity factor between substations and capacity factor of the power plant.

A.1.48 , 0.446 B.1.48 , 0.335

C. 1.75 , 0.335 D. 1.75, 0.446

A 6 stage centrifugal pump delivers 1600 GPM of water against the net pressure rise of 800 Lbf /in^2. what is the specific speed if it rotates at 1750 RPM.

A.248.54 B.952.82

C. 1020 D. 546.23

A 5inches diameter cylinder rotates at 3600RPM. Air is flowing past the cylinder at 100ft/s. How much is the lift on the cylinder per unit length? The density of air is 0.00234 slug/ft^3. A.0.15 lb/ft B.11.75 lb/ft

C. 20.75 lb/ft D. 23.65 lb/ft

The suction pressure of a 4-stage compressor is 140 Kpa. It compresses air at the rate of 15 m^3/min, clearance is about 8% and 200rpm. The compressor discharges compressed air at pressure of 1000 Kpa. The compressor uses inter-cooling determine the ideal pressure at the first stage intercooler.

A.228.87 Kpa B.345.67 Kpa

C. 453.45 Kpa D. 345.45 Kpa

A vertical draft tube is installed on a francis turbine and the total head to the center of the spiral casing at the inlet is 38m and velocity of water at the inlet is 5m/s. the discharge is 2.1m^3/s. the hydraulic effcy. is 0.87 and over all effcy. Is 0.84. the velocity at the inlet ant exit are 5m/s and 1.5m/s respectively. The top of the draft tube is 1m below the center line of the spiral casing while the tailrace (water) lever is 3m from the top of the draft tube. There is no velocity of whirl at either top or bottom of draft tube and leakage losses are negligible. What is the power output in the turbine in KW?

A.748.8 KW B.682.9 KW

C. 901.3 KW D. 832.6 KW

A windmill with a 6m radius rotor is to be installed where atmospheric pressure conditions prevail at 101.325Kpa and 21 deg C. it was observed that wind is blowing steadily at an average velocity of 20m/s. assuming that conversion effcy. Is somewhere between 20% to 25%, determine the maximum available power from the windmill.

A.124.78 KW B. 135.81 KW

C. 167.25 KW D. 225.78 KW

Calculate the scale ratio for the model turbine if the prototype to model speed and head ratio is 0.675 and 12 respectively.

A.5.54 B.5.13

C. 5.82 D. 5.32

A pelton wheel running at a speed of 600rpm is driven by 2 similar jets. At this speed it transmit 600Kw to the shaft. The effcy of the runner is 90% and the velocity of the fluid at inlet to the bucket is 50m/s. estimate the diameter of its jet.

A.0.0165 m B.0.0435 m

C. 0.0143 m D. 0.0123 m

An impulse turbine which has a diameter, D = 60 inch. Speed N=350rpm, bucket angle B=160 deg., coef of velocity Cv=0.98, relative speed O|=0.45, a generator em=0.90, k=0.90, and aa jet diameter from nozzle of 6 inches. Compute the power input in HP?

A.2,862 Hp B.2,521 Hp

C. 2,933 Hp D. 2,366 Hp

If the specific heat at constant pressure for CO2 is given as 0.201Btu/lb-R, whatis the value of the specific heat at constant volume?

A.0.156 Btu/lb-R B.0.365 Btu/lb-R

C. 0.435 Btu/lb-R D. 0.435 Btu/lb-R

Estimate the circulation ratio in the down comer riser circuit when the mass of water flowing. Through it is 10 kg/s, while the riser exit saturated liquid water flows at 8.5 kg/s.

A.1.18 B.6.67

C. 5.9 D. 0.85

For a certain drier, the feed has a moisture regain of 160%. Determine the percent moisture of the feed. A.60 B.62.43

C. 61.54 D. 50

The Reynolds number of a sphere falling in the air is 1x10^6. If the sphere’s radius is 1ft. What is its velocity? A.2.5 ft/s B. 5.1 ft/s

C. 40.6 ft/s D. 81.2 ft/s

What is the thermal efficiency of an airstandard Brayton cycle if the pressure ratio is 10. s A.48.21% B.50.16%

C. 45.36% D. 42.44%

A refrigeration cycle system produces 20 kg/hr of ice from water at 20 deg C. Find the tonnage of the unit.

A. 0.66 B. 0.55

C. 0.77 D. 0.88

A two meter id pipe is flowing half full. What is the hydraulic radius?

A.1.00 m B. 0.50 m

C. 1.50 m D. 1.75 m

A 1 kg steel ( C = 0.5 kJ/kg.K) rivet cools from 800K to 300 K upon being installed in a riveted structure. The entropy change in kJ/K of this rivet is.

A.-0.245 B. -0.49

C. -0.631 D. -0.546

A dam 15m high has water behind it to a depth of 10 m. what is the overturning force per meter of width?

A.1.6 MJ B. 2.0 MJ

C. 2.3 MJ D. 1.8 MJ

What is the lifting force in kN for a 10 m diameter spherical balloon with helium inside at 101 kPa and 320 K surrounded by air at 101 kPa and 298.15K?

A.17.38 kN B. 5.28 kN

C. 18.73 kN D. 8.25 kN

A vertical bulkhead 9.6 m wide and 6 m deep separates two tanks. One tank contains oil of relative density of 0.8 to a depth of 4.2 m. find the total load on the bulkhead in MN. A.1.472 B. 2.013

C. 1.168 D. 2.347

Fresh water flows through a short smooth horizontal pipe of tapered bore. At the large end the velocity is 1.5 m/s. at the small end the pressure is 14 kN/m^2. Calculate the velocity at this end.

A.4.4 m/s B.5.5 m/s

C. 6.6 m/s D. 3.3 m/s

In a Rankine cycle, steam turbine with exhaust enthalpy of 2500 kJ/kg of steam. If the exit enthalpy of a condenser is 500 kJ/kg, what is the heat rejected? A.1000 KW B.1200 KW

C. 1700 KW D. 1500 KW

A commercial air conditioner is rated by means of its EER or energy effcy ratio. For a certain airconditioner with a cooling capacity of 4 KW and requires 1000 W, approximate the EER of this unit.

A.13.65 B.12.80

C. 10.10 D. 11.11

In a simple gas turbine plant working on the ideal constant pressure cycle, air taken into the compressor at 1 bar, 16 deg C and delivered at 5.4 bar. If the temperature at turbine inlet is 700 deg C. Calculate the ideal thermal efficiency? Take k = 1.4.

A.38.23 % B.42.61%

C. 45.66 % D. 35.38 %

Circulation in the 10 m riser if the specific volume in the down comer is 0.0014 and in the riser top is 0.0032 m^3/kg.

A.19.71 kPa B.12.45 kpa

C. 21.45 kPa D. 15. 74 kPa

Find the COP of the refrigeration whose energy supply equals one-fourth the amount of heat it extraxts.

A.3 B. 4

C. 5 D. 2

The down comer-riser circuit receives saturated water a rate of 10.5kg/s from the boiler. If circulation ratio is 11.5, what is the top dryness fraction? A.0.095

C. 0.081

B. 0.087

D. 0.913

Three liquids of specific gravities 0.7, 0.8 and 0.9 respectively are mixed in the proportion of 3,4 and 5 by mass. Find the relative density of the mixture. A.0.81 B.0.62

C. 0.73 D. 0.92

What would be the resistance of the scale deposit if the overall heat coefficient for a tube reduced from 1500 W/m^2.K to 1100 W/m^2.K?

A.3500 W/m^2.K B.2600 W/m^2.K

C. 4125 W/m^2.K D 5000 W/m^2.K

A round 457 rpm mm duct is to be replaced by a rectangular duct with aspect ratio of 4:1 what should be the dimensions of the rectangular duct?

A.884 mm and 221 mm B.900 mm and 250 mm C. 800 mm and 200 mm D. 700 mm and 150 mm

The 600 kg hammer of a pile drive is lifted a 2m above the piling head. If the hammer is released, what will be its velocity at the instant it strikes the piling? Local g = 9.65 m/s^2 A.6.21 m/s B.3.25 m/s

C. 1.2 m/s D. 4.5 m/s

A 3 hp refrigerator or heat pump operates between 0 deg F and 100deg F. the maximum theoretical heat that can be transferred from the cold reservoir is nearest to:

A.1300 Btu/hr B.2300 Btu/hr

C. 35000 Btu/hr D. 43000 Btu/hr

A window type air conditioner is rated with compressor power of 1 Hp. The unit has an EER of 11.1. Determine the maximum cooling capacity of the unit in tons of refrigeration.

A.0.54 B.0.63

C. 0.69 D. 0.51

A potential waterfall for hydroelectric power plant has water available at a rate of 160 m^3/s under a head of 18 m. find the number of Francis turbines required if it runs at 120 rmp, specific speed of 350 and 80% hydraulic efficiency.

A.2 B.3

C. 4 D. 6

A galvanized steel duct of 0.4 m diameter and 20 m long carries air at 20 deg C and 1.013 bar. If the surface roughness for the ducts is0.15 mm, find the roughness factor. A. 0.000475 B. 0.000365

C. 0.000375 D. 0.000485

The mechanical effcy of a single cylinder four stroke engine is 80%. The frictional power is estimated to be 25 kW. Calculate the brake power developed by the engine. A.250 kW B.150 kW

C. 100 kW D. 200 kW

A rectangular duct section 35 cm x 50 cm size carries 75 m^3/min of air having density of 1.15 kg/m^3. if the friction factor of sheet metal is 0.01, find the pressure loss per 100 m length of duct.

A.29 mm of H2O B.36 mm of H2O

C. 25 mm of H2O D. 35 mm of H2O

About 3 hp per ton is required to maintain a temperature of -40 deg C in a refrigerator. If the refrigerator works on the reverse carnot cycle, determine the heat rejected to the sink per ton of refrigeration. A.69.72 kCal/min B.70.24 kCal/min

C. 81.61 kCal/min D. 84.65 kCal/min

Consider a 1200 kg car cruising steadily on a level road at 90 km/h. now the car starts climbing a hill that is sloped 30 deg from horizontal. If the velocity of the car is to remain constant during climbing, determine the additional power that be delivered by the engine.

A.197 Hp B.207 hp

C. 159 hp d. 105 hp

A pelton type turbine was installed 30 m below the head gate of the penstock. The head loss due to friction is 15% of the given elevation. The length of the penstock is 80 m and the coefficient of friction is 0.00093. determine the power output in kW. A.14,292.74 B.12,492.74

C.19,242.74 D. 17442.92

In a geothermal power plant, the enthalpies of the ground water and the turbine inlet are 1500 kJ/kg and 3500 kJ/kg respectively. If the enthalpy of the hot water in the flash tank is 700 kJ/kg and the mass flow rate of steam is 15 kg/s, what is the mass flow rate of ground water?

A.52.50 kg/s B.48.69 kg/s

C. 55.49 kg/s D. 345.48 kg/s

An amount of air with BD temperature of 35 deg C. WB temperature of 28 deg C is passed through an air conditioner and exhaust at DB temperature of 24 deg C and RH of 50%. Cooling coil temperature is approximately 18 deg C. determine the by-pass factor of the air conditioning system. A.0.69 B.0.43

C. 0.26 D. 0.35

An average car consumes about 5 L of gasoline a day, and the capacity of the fuel tank of a car is about 50L. Therefore, a car needs to be refueled once every 10 days. Also the density of gasoline ranges from 0.68 to 0.78 kg/L, and its lower heating value is about 44,000kJ/kg (that is, 44,000kJ of heat is released when 1 kg of gasoline is completely burned). Suppose all the problems associated with the radioactivity and waste disposal of nuclear fuels are resolve, and a car is to be powered by U-235. if a new car becomes equipped with 0.1kg of the nuclear fuel U-235, determine if this car will ever need refueling under average driving condition.

A. The car needs to be refueled after 10 years B. The car needs to be refueled after 50 years C. The car does not needs to be refueled D. The car needs to be refueled after 100 years

Steam at 1.5 Mpa, 300 deg. C is supplied to an engine and exhaust at 0.014 Mpa. The consumption of steam is 28,500 kg/hr when the indicated power is 3000 KW. Calculate the steam consumption in kg/KW-hr and the indicated thermal eff’cy.

A. 9.5 kg/KW hr, 13.45%

B. 10 kg/KW-hr, 11.45% C. 8.5 kg/KW/hr, 12.34% D. 10.5 kg/KW-hr, 10.47%

Steam enters the nozzle of an impulse turbine at 2 Mpa,300 deg. C and leaves at 0.30 Mpa, 0.98 dry. The angle of the nozzles is 20 deg. To the direction of motion of the blades and blade velocity is 380 m/s. Calculate the velocity of the steam leaving the nozzles.

A.829.4 m/s B.924.8 m/s

C. 545.7 m/s D. 754.8 m/s

The pressure and temp. entering the turbine are 1800 Kpa and 38 deg. C. The pressure leaving the turbine is 20 Kpa. The quality of steam entering the condenser is 90%. What is the turbine work? Steam properties;@ 1800 Kpa and 380 deg. C (h= 3207.2 KJ/kg) @ 20 Kpa, hf=251.4 KJ/kg hg=2609.7 KJ/kg. A.1833.33 Kj/kg B.1333.8 KJ/kg

C. 597.5 KJ/kg D. 833.33 KJ/kg

A hydro-electric generating station is supplied from a reservoir of capacity 6,000,000 m^3 at head of 170 m. Assume hydraulic eff’cy of 80% and electrical eff’cy of 90%. The fall in the reservoir level after a load of 15 MW has been supplied for 3 hrs, If the area of the reservoir is 2.5 km^2 is closest to:

A.5.39 cm B.4.32 cm

C. 5.98 cm D. 4.83 cm

Air is drawn into a gas turbine working on the constant pressure cycle at 1 bar, 21 deg. C and compressed to 5.7 bar. The temp. at the end of heat supply is 680 deg. C. Taking expansion and compression to be adiabatic where Cv= 0.718 KJ/kg-K, Cp= 1.055 KJ/kg-K, Calculate the heat energy supplied per kg at constant pressure.

A.472 KJ/kg B.389 KJ/kg

C. 501 KJ/kg D. 489 K/kg

A small swimming pool 25 x 75 ft is to be filled with water at a temperature of 70 deg. F to a depth of 5 ft. Hot water at 160 deg. F and cooled water at 40 deg. F are available. How many cubic ft of each (neglecting the thermal capacity of the tank itself) should be used in filling the tank?

A.2344 ft^3 B.3423 ft^3

C. 2345 ft^3 D. 3145 ft ^3

A research laboratory building is to be heated and ventilated, air is to be supplied to a room 12 m by 18 m from the outside at the rate of 1 m^3/min air replacement for each square meter of floor space. The design condition include 20 deg.C room temperature and -20 deg.C outside air temperature. In addition the pressure in the room is to be maintained at a positive pressure of 7 Kpa, to ensure that there will be no air laekage into the laboratory. How much heat would be required to condition the air for this room?

A.177.11 KW C.168.7 KW B.154.8 KW D. 185.3 KW

A circular cylinder 4 ft long and 3 ft in diameter is in an air stream. The flow velocity is 5ft/s perpendicular to the axis of the cylinder. Given that the coefficient of drag on the cylinder is 1.3 and the density of air is 0.00234 slug/ft^3. What is the force in the cylinder?

A.0.09 B.0.11

C. 0.46 D. 0.91

A reverse Carnot cycle air refrigeration equipment has a compressor working with a compression ratio of 12. The temp. limits of the cycle are 300 K and 270 K. Determine the refrigerating effect of the unit.

A.2.45 TR B.1.86TR

C. 2.06 TR D. 1.26 TR

The filament of a 100W bulb maybe considered blackbody radiating into a black enclosure at 80 deg. C. Considering only radiation, calculate the filament temp. in deg. C, if the filament diameter is 0.10 mm and the length is 6 cm.

A. 3109.97deg.C B. 2837 deg. C

C. 3245.45 deg.C D. 2313.5 deg.C

A circular duct of 40 cm is selected to carry air in an air-conditioner space at a velocity of 440 m/min to keep the noise at desired level. If this duct is replaced by a rectangular duct of aspect ratio 1.5, find the size of rectangular duct for equal friction method when the velocity of air in two ducts is same. A.45cm x 30 cm B.40 cm x 25 cm

C. 50 cm x 35 cm D. 30 cm x 15 cm

45 KW of the shaft power is developed by a turbine working under an available head of 40 m. The energy transferred from the water to the runner is 350 J. Assuming a mechanical eff’cy of 95%, what is the discharge through the turbine in m^3/s? A.0.0345 B.0.135

C. 1.511 D. 1.234

A cast iron pipe of equilateral triangular cross section with side length of 20.75 in. has water flowing through it. The flow rate is 6000 gpm (13.37ft^3/s) and the friction factor for the pipe is 0.017. What is the pressure drop in a 100 ft section?

A.211.8 lb/ft^2 B.311.8 lb/ft^2

C. 123.5 lb/ft^2 D. 178.5 lb/ft^2

A block of wood floats in water with 6 inches projecting above the water surface. If the same block were placed in alcohol of specific gravity 0.82, the block would , project 4 inches above the water surface of alcohol. Determine the wood of block.

A.0.603 B.0.504

C. 0.701 D. .243

Air is used in a Carnot engine where the volumes at the beginning of the constant temp. heat addition and end of the constant temp. heat rejection are 0.456 cm^3 and 6.78 cm^3 respectively. Calculate the thermal eff’cy.

A.0.667 B.0.656

C. 0.786 D. 0.765

What should be the cooling requirement due to emission of body to maintain a comfortable temp. in a dance hall that had an attendance of 1500 people if it has been determined that 75% of the people will be dancing and others will be seated. Test have shown that an adult will give off 71.8 W of sensible heat while engaging in moderate dancing and 57.1 of sensible heat while sitting. The latent heat emissions for similar situations have been found to equal 177.3 W for dancers and 45 .5 W for sitters.

A.200 KW B.267 KW

C. 301 KW D. 319 KW

A reverse Carnot cycle air conditioner of 4 TR capacity operates with a cooling coil of temp. of 5 deg. C. The surrounding air at 45 deg. C is used as a cooling medium rising to the temp. of 55 deg. C. The temp. of heat rejection is 60 deg. C. Determine the mass flow rate of air entering the heat exchanger. A.0.07 kg/s B.0.12 kg/s

C. 0.16 kg/s D. 0.04 kg/s

Air is compressed in a diesel engine from an initial pressure of 13 psi and a temp. of 120 deg. F to onetwelve of its initial volume. Calculate the final temp. and pressure assuming the compression to be adiabatic.

A.1570 deg. R B.2000 deg. R

C. 1548 deg. R D.1786 deg. R

The flow rate of water through a cast iron pipe is 5000 gallons per minute. The diameter of the pipe is 1 foot and the coefficient of friction is 0.0173. What is the pressure drop over a 100 foot length pipe?

A.221.078 lb /ft^2 C. 313.45 lb/ft^2 B.411.058 lb/ft^2 D. 337.26lb/ft^2

What is the thermal efficiency of an air-standard brayton cycle if the air enters and leaves the turbine at 1000 K and 550 K respectively?

A.40.74% B.44.99%

C. 50.38% D. 54.86%

A cylinder 10 ft long and 2 ft in diameter is suspended in air flowing at 8ft/s. the density of air is 0.00234 slug/ft^3 and the coefficient of drag of the sphere is 1.3. What is the drag on the cylinder?

A.0.39 lbf B.1.95 lbf

C. 4.99 lbf D. 0.311lbf

Consider a person standing in a breezy room at 20 deg.C. determined the total rate of heat transfer from this person if the exposed surface area and the average outer surface temperature of the person are 1.6 m^2 and 29 deg.C, respectively, and the conversion heat transfer coefficient is 6 W/m^2-C.

A.168.1 W B.174.5 W

C. 137.5 W D. 154.7 W

About 3 HP per ton is required to maintain a temp. of -40 deg. C in a refrigerator. If the refrigerator works on the reverse Carnot cycle, determine the heat rejected to the sink per ton of refrigeration.

A.69.72 kCal/min. C. 81.61 kCal/min. B.70.44 kCal/min. D. 84.65 kCal/min.

What is the over-all eff’cy of a 30 MW steam power plant with a boiler eff’cy of 92%, cycle eff’cy of 44%, mechanical loss of 5%, generator eff’cy of 93% and gross power production of 32,000 KW.

A.33.98 % B.36.88 %

C. 35.44 % D. 38.84 %

In a simple gas turbine plant working on the ideal constant pressure cycle, air is taken into the compressor at 1 bar, 16 deg. C and delivered at 5.4 bar. If the temp. at turbine inlet is 700 deg. C. Calculate the ideal thermal eff’cy? Take k=1.4

A.38.23 % B.42.61 %

C. 45.66 % D. 35.38 %

Steam is expanded through a nozzle and the enthalpy drop per kg of steam from the initial pressure to the final pressure is 60 KJ. Neglecting friction, find the velocity of discharge and the exit area of the nozzle to pass 0.20 kg/s if the specific volume of the steam at exit is 1.5 m^3/kg.

A. 346.4 m/s , 879 m^2 B. 356 m/s , 278 m^2 C. 765.6 m/s , 467 m^2 D. 346.4 m/s , 866 m^2

Calculate the thermal diffusivity of pure aluminum with density of 2,702 kg/m^3, thermal conductivity of 237 W/m-K and specific heat of 0.903 KJ/kg-K.

A. 97.1 x 10^-6 m^2/s B. 23.25 x 10^-6 m^2/s C. 14.9 x 10^-6 m^2/s D. 34.5 x 10^-6 m^2/s

If the conditioned space receives 80,000 kg of air per hour and air supply temp. rises about 10 deg. C and air picks up latent heat of about 150 KW. Determine the sensible heat factor of the system.

A.0.597 B.0.554

C. 0.612 D. 0.509

A horizontal jet fresh water 40 mm diameter impinges on a stationary flat plate which is perpendicular to the jet, and the direct force to prevent the plate moving is measure d to be 225 N. Assuming that there is no splash back of water, find the initial velocity of the jet.

A.13.39 m/s B.12.42 m/s

C. 16.21 m/s D. 14.34m/s

There are required 2200 KW net, from a gas turbine unit for pumping of crude oil. Air enters the compressor section at 100 Kpa, 280 K, the pressure ratio Rp=10. The turbine section recieves the hot gases at 1,100 K. assume the closed brayton cycle and determine the required air flow.

A.7.91 kg/s B.7.16 kg/s

C. 8.11 kg/s D. 8.91 kg/s

A pelton wheel running at a speed of 400 rpm is driven by a water power of 5000 KW. The elevation is 150 m and the velocity coefficient is 0.97. find the number of jets required if if its diameter is limited at 0.15m.

A.3 B.4

C. 5 D. 6

The sun generates an average of 2 KW/m^2 when tapped as source of energy where in a flat plate collector with an area of 1.5 m^2 is used. Flow rate of water inside the collector is 40 liters per hour. Calculate for the temperature rise of the working fluid in deg.C. A.65.14 deg. C B.60.15 deg.C

C. 55.14 deg.C D. 50.15 deg.C

A refrigerator is rated at a USA one ton capacity, it maintains a cooling temperature 4.4 deg, C. (EVAPORATIVE TEMPERATURE). A refrigerant with a refrigerating effect of 136 kj/kg is in the condenser just a head of the expansion valve. If the refrigerant vapor has a density of 19.80 kg/m^3, what should be the capacity of the compressur?

A.0.078 m^3/min C. 0.102 m^3/min B.0.091 m^3/min D. 0.113 m^3/min

A cold storage is required to store 20 tons fish. The fish is supplied at a temperature of 30 deg. C. The specific heat of fish above the freezing point is 2.93 KJ/kg. K. The fish is stored in cold storage that is maintained at -8 deg. C. The freezing point of that is maintained at -4 deg. C. The latent heat of solidification of the fish is 235 KJ/kg. If the plant requires 75 KW to drive it, find the time taken to achieve cooling. Assume the actual COP as 0.3 times the Carnot COP of the refrigerating plant.

A.14.72 hrs B.9.64 hrs

C. 10.41 hrs D. 12.03 hrs

A rectangular duct section 35 cm x 50 cm size carries 75 m^3/min. of air having a density of 1.15 kg/m^3. Determine the equivalent diameter of circular duct if the quantity of air carried in both cases is the same.

A.0.26 m B.0.36 m

C. 0.46 m D. 0.56 m

The cubic capacity of a 4-stroke over square park ignition engine is 245 cm^3. The over square ratio is 1.1. The clearance volume is 27.2 cm^3. Calculate the stroke.

A.6.36 cm B.3.42 cm

C. 2.38 cm D. 8.45 cm

Steam enters the turbine at the rate of 11,000 kg/hr with enthalpies of 3,000 KJ/kg and 1,000 KJ/kg at the entrance and exhaust respectively. Steam is extracted from the turbine at 3,500 kg/hr for heating purposes with enthalpy of 2,700 KJ/kg. Calculate the turbine work.

A.5,468.33 KW C. 4,458.33 KW B.4,569.33 KW D. 5,425.33 KW

The two phase flow in a riser has a volume quality and moisture of 0.60 and 90% respectively. If the ratio of the specific volume of vapor to that of the liquids is 20, estimate the slip ratio.

A.1.48 B.1.67

C. 1.74 D. 1.32

Dry saturated steam at 8 bar (0.8 Mpa) is expanded in turbine nozzles to a pressure of 5 bar 0.97 dry. Find the velocity at exit. If the area at the exit is 14.5 cm^2, find the mass flow of the steam in kg/s. Steam properties: At 8 bar (0.8 MPa), At 5 bar; (0.5 Mpa) Vg=0.3748m^3/kg, hf=640 KJ/kg, hg=2769 KJ/kg, hfg=2109 KJ/kg

A.1.625 kg/s, 407.4 m/s B. 2.456 kg/s, 786.5 m/s C. 2.257 kg/s, 233.8 m/s D. 3.125 kg/s, 125.7 m/s

A proposed hydro-electric plant site, the average elevation of head water is 600m, the tail water elevation is 480 m. The average annual water flow is determined to be equal to that volume flowing through a rectangular channel 4 m wide and 0.5 m deep an average velocity of 5.5 m/s. Assuming that the plant will operate 350 days per year, find the annual energy in KW-hr that the plant site can develop if the hydraulic turbine that will be used has an eff’cy of 80% and generator eff’cy of 92 %. Consider a headwork loss of 4 % of the available head.

A.67,458,581 B.76,854,851

C. 54,786,518 D. 48,576,185

Steam with an enthalpy of 800 kCal/kg enters a nozzle at a velocity of 80m/s. Find the velocity of he steam at the exit of the nozzle if its enthalpy is reduced to 750 kCal/kg, assuming the nozzle is horizontal and disregarding heat losses. Take g= 9.81 m/s^2 and J constant = 427 kg m/kCal.

A.452.37 m/s B.245.45 m/s

C. 651.92 m/s D. 427.54 m/s

A double suction heater pump is moving 1.1 liters/s turns at 900 rpm. The pump adds 7 m head of water. What is the specific speed?

A.155.1 rpm B.255.7 rpm

C. 500.7 rpm D. 243.34 rpm

Two different types of heat exchangers are being considered parallel flow and counter flow. The heating fluid is water at a rate of 4 kg/min which enters at 60 deg C and leaves at 40 deg C. the heated fluid is also water at a rate of 8 kg/min. it enters at 10 deg C and leaves at 20 deg C. what would be the relative size of the two types of heat exchanger?

A.They would be equal in size B.The counter flow heat exchanger would 10% larger C. The parallel flow heat exchanger be 5% smaller D.The parallel flow heat exchanger would be 6% larger

Calculate the use factor of a power plant if the capacity factor is 35% and it operates 8000 hrs during the year?

A.38.325% B.33.825%

C. 35.823% D. 32.538%

The system shown in the figure consists in the part of the transformer serving customers X,Y, Z. Estimate the peak load on the transformer. X - store building with 5 KW lighting, 25 KW small motor power Y–store building with 18 KW lighting, 35 KW small motor power Z – office building with 55 KW lighting, 80 KW large motor power

A.75.08 KW B.85.07 KW

C. 95.84 KW D. 105.76 KW

A daily load curve which exhibited a 15 minute peak of 150,000 KW is drawn to scales of 1 cm = 3 hrs and 1 cm = 10,000 KW. The area under the curve is measured by a planimeter and found to be 60 cm^2. what is the load factor based on the 15 minute peak?

A.0.50 B.0.75

C. 0.55 D. 0.65

If the rated capacity of the steam is 50,000 KW and the actual maximum demand is 35,000 KW, what is the utilization factor?

A.0.60 B.0.70

C. 0.50 D. 0.80

A hydro electric plant having sq. km reservoir area and 100 m head is used to generate power. The energy utilized by the consumers whose load is connected to the power plant during a five hour period is 13.5 x 10^6 KW-hr. The over-all generation eff’cy is 75 %. Find the fall in the height of water in the reservoir after the 5 hr period.

A.2.13 B.1.32

C. 3.21 D. 0.53

A Pelton wheel is to be designed to run at 300 rpm under an effective head of 150 m. The ratio of the nozzle diameter to the diameter of the pitch circle is 1/12. Assuming eff’cy of 84 %, what is the size of the wheel in meter. Assume a speed ratio of 0.45.

A.1.05 B.2.00

C. 1.55 D. 2.86

An engine requires 4,300 kg of dry steam per hour. The quality of steam is 90 %. What must be the weight of steam?

A.4,778 kg/hr B.4,000 kg/hr

C. 5,258 kg/hr D. 6,000 kg/hr

After checking on the properties and phase descriptions of water, the quality is found to be X=0.70. How many percent of the mass is in the liquid phase?

A.70 % B.0.70 %

C. 100 % D. 30 %

What is the hydraulic gradient of a 1 mile, 17 inches inside diameter pipe when 3,300 gal/min of water flow with f= 0.03.

A.0.00714 B.0.00614

C. 0.00234 D. 0.00187

1. A carnot refrigerator operates in a room in which the

temperature is 25 C and consumes 2 kW of power when operating. If the food compartment of the refrigerator is to be maintained at 3 oC, determine the rate of heat removal from the food compartment a. 1504. 8 KJ/min b. 1625 KJ/min c. 12.86 KJ/min d. 9.57 KJ/min

2. A household refrigerator with EER 8.0 removes heat from the refrigerated space at a rate of 90 kJ/min. Determine the rate of heat transfer to the kitchen air

a.101.25 kJ/min b.128.46 kJ/min c.63.05 kJ/min d.80 kJ/min

3. An air conditioning system is used to maintain a house at 75oF when the temperature outside is95oF. The house is gaining heat through the walls and windows at a rate of 1250 Btu/min. determine the minimum power input required for this air conditioning system. a. 10.06 hp b. 1.41 hp c. 1.36 hp d. 7.94 hp

4. A refrigeration system is to cool bread loaves with an average mass of 450 g from 22 C to -10 C at rate of 500 loaves per hour by refrigerated air. Taking the average specific and latent heats of bread to be 2.93 KJ/kg C and 109.3 KJ/kg, respectively determine the product load.

a.541.7 kJ/min b. 761.5 kJ/min c. 351.6 kJ/min d.409.9 kJ/min

5. A house that was heated by electric resistance heaters consumed 1200 kWh of electric energy in a winter month. If this house were heated instead by a heat pump that has an average performance factor PF of 2.4, determine how much money the home ewner would be saved that month. Assume orice of 0.085$/kWh for electricity. a. $42.5 b. $102 c. $59.50 d. $97.75

An amonia simple saturation cycle operates with a suction pressure of 29.6kPa and a condenser pressure of 1204 kPa develops 15 tons of refrigeration. Determine the theoretical horsepower of the compressor. The following enthalpies have been found: condenser entrance 1653 kJ/kg, exit 346.6kJ/kg; compressor entrance 1450.2 kJ/kg exit 1653kj/kg a. 7.23 hp b. 15hp c. 13hp d. 8.23 hp

An amonia ice plant operates between a condenser temperature of 35 oC and evaporator of -15oC. it produces 10 metric tons of ice per day from water at 30oC to ice -5oC. Assuming simple saturation cycle, determine the horsepower of the motor if the adiabatic efficiency of the compressor nc= . 95. The specific heat of ice is 2.094kj/kg oC and the latent heat is 335 kj/kg From the table for ammonia the following enthalpies are: condenser entrance= 1703kj/kg, exit 366.1 kj/kg; compressor entrance = 1443.9 kJ/kg, exit =1703kJ/kg

a. 17.68 hp b. 15.5 hp c. 18.61 hp d. 21. 9 hp

A freon 22 air conditioning under standard operation conditions of 35 C condensing and 5 C evaporation temperatures. The volume flow rate entering the compressor is 23.72 L/s. Determine the refrigeration capacity if the refrigerating effect is 164 kJ/kg. From the table for R22 the specific volume at the compressor entrance is 40.36 L/kg a. 339 b. 96.4 c. 79.3 d. 27.4

TR TR TR TR

The refrigerating volume flow rate at the entrance of compressor were obtained from a test on a twin cylinder, single acting 15 cm x 20 cm, 320 rpm compressor ammonia refrigerating plant to be 3 L/s. Determine the volumetric efficiency of the compressor. a.77.65 % b.97.6 % c.87.6% d.65.65%

A vapor compression refrigeration system is designed to have a 80 tons refrigerating of refrigeration . Its actual cop is 4 and 30 percent of the power supplied to the compressor is lost in the form of friction and cylinder losses. Determine condenser cooling water required for a temperature rise of 10oC. a. 5.63 kg/s b. 4.47 kg/s c. 7.82 kg/s d. 9.0 kg/s

A twin cylinder ammonnia compressor with volume displacement of 14,726 cm3 operates at 300 rpm. Condenser and evaporator pressure are 1200 Kpa and 227 Kpa respectively. Specific volume of refrigerant at he entrance of compressor is 582.2 L/kg. compression process is polytropic with n = 1.20 and clerance factor of compressor is 2 percent. Determine horsepower required.

a.60 hp b.80 hp c.70 hp d.90 hp

A reversed carnot cycle has a refrigerating COP of 2.5. determine the ratio Th/Tl ?

a.1.4 b.1.25 c.1.5 d.1.2

Three thousand cubic feet per minute of air and circulated over an air circulated over an air-cooled condenser. If the load on the condenser is 64800 BTU/hr, compute the temperature rise of the air passing over the condenser. Specific volume of standard air (13.3) ft^3/lb). a.10 F b.20 F c.15 F d.25F

Saturated vapor ammonia at -16 C (H1=1442.6 kJ/kg) leaves the evaporator and enters the compressor at -6 C ( H1= 1465 Kj/kg). The refrigerant leaves the condenser as saturated liquid at 40 C ( h4=390.6 KJ/kg). And enter the expansion valve at 35 C (h5=366.1 KJ/kg. Heat rejected from the condenser amount to 50kW. The work to compressor is 208 kJ/kg, while the heat loss from compressor is 33 kJ/kg. if 95 kJ/kg of heat are lost in the piping between the compressor discharge and condenser inlet, determine the refrigerating capacity of the capacity of the system.

a. 49.5 TR b. 12.88 TR c. 46.61 TR d. 13.24 TR

In an actual refrigeration cycle using R12 as working fluid, the refrigerant flow rate is 0.05 kg/s. vapor enters the expansion valve at 1.15 Mpa, 40 C (h= 238.5 kJ/kg) and leaves the evaporator at 175 kPa,-15 C (h=345 kJ/kg). The electric input to motor driving the compressor is measured and found 3.0 kW. Motor efficiency at this load is 92 percent and mechanical efficiency 82%. Determine the actual coefficient of performance for this cycle.

a.1.58 b.1.78 c.2.36 d.1.34

In ammonia refrigeration system the temperature in the evaporator is -12 C and the ammonia at the evaporator entry is 0.1511 dry while at exit is .95 dry. If the rate of ammonia circulation is 5.64kg/min, determine the refrigerating capacity of the system . Enthalpy of saturated liquid and vapor at -12 C is 144.929 KJ/kg and 144.74 kJ/kg respectively. a. 17.82 TR b. 27.82 TR c. 34.82 TR d. 4.82 TR

A two stage cascade vapor compression refrigeration system uses ammonia in the low-temperature loop and R12 in the high temperature loop. The ammonia provides 15 tons cooling. If the high loop temperature requires 10.12 kW compressor power and loop 15.93kW, determine the COP of the system. a. 2.027 b. 3.314 c. 5.22 d. 9.1

TR TR TR TR

When a man returns to his well sealed house on a summer day, he finds that the house is at 32 C. he turns on the air conditioner, which cools the entire house to 20 C in 15 min. if COP of the air conditioner system is 2.5. determine the power drawn by the air conditioners. Assume the entire mass within the house is equivalent to 800kg of air for which c=0.72 kJ/kg C a. 7.68 kW b. 19.2 kW c. 3.07 kW d. 12.03 kW

It is desired to double the cop of a reversed carnot engine for cooling from 5.0 by raising the temperature of heat addition while keeping the temperature of heat rejection constant. By what percentage must the temperature of heat addition be raised? a.10.1 % b.8.1 % c.9.1 % d.7.1 %

A single acting compressor has a volumetric efficiency of 87%, operates at 500 rpm. It takes in ammonia at 277 kPa and discharge it at 1204 kPa. The ammonia handled is 4.13 m 3 /min measured at the discharge condition. If the compression is polytropic with n = 1.20, determine the piston displacement per stroke.

a.0.0095 m3 c. 19.7 m3 b.16.59 m3 d. 0.03814 m3

21. An ammonia water cooled compressor receives the refrigerant at specific volume 62 L/kg. It has a piston displacement rate of 5 m^3/min. If a squirrel cage motor running at 1200 rpm drives the compressor and average piston speed is 490 m/min, calculate size of cylinder bore.

A.20.4 cm C.26.0 cm B.16.13 cm D. 13.6 cm

22. A small pump serving as model, when tested in laboratory using water at 3600 rpm, delivered 3.0 cfs at a head of 125ft. If the efficiency of this model pump is 84%.Predict the horsepower input to the prototype pump if it is to develop the same head as model pump and the model pump has scale ratio of 1:10.Assume the efficiency of the prototype pump is 90%.

A.50.6 hp B.3740 hp

C. 4730 hp D. 60.5 hp

Pump at its best eff’cy point (BEP) has a capacity of 10,500 gpm while developing a head of 60 ft at a rotative speed of 1450 rpm. What is the specific speed of the pump?

A.2,760 B.2,476

C. 1,450 D. 6,892

A pump will be installed below the reservoir water surface with a required net positive suction head (NPSHR) of 50 ft. The barometric pressure is 14.3 psia, and the vapor pressure is 0.5 psia. Assume friction losses in the intake piping are 5 ft. Find the maximum allowable elevation of the pump relative to the water surface intake to avoid cavitation.

A.45 ft C. 55 ft B.18.2 ft D. 23.2 ft

Centrifugal pump at best point (BEP). Assume the pump characteristic are head, h=7 m, flow rate, Q= 19 liters/sec, and rotative speed n= 1,170 rpm. Find the specific speed in SI units.

A.0.4 B.10.41

C. 0.71 D. 3.94

A 15 in. diameter fan operates at 1600 rpm and develops a head of 6 in. of water and delivers 120 cfm. What volumetric capacity for geometrically similar fan that will develop 6 in of water at 1300 rpm?

A.147.70 cfm B.97.5 cfm

C. 181.8 cfm D. 79.2 cfm

A radial flow pump operating at maximum eff’cy at a specific speed of 2500 is to deliver 260 gpm against a head of 129 ft at a rotative speed of 2100 rpm. Find the required number of stages(i.e.. Impellers).

A.2 stages B.4 stages

C. 3 stages D. 5 stages

How many identical turbine, operating at 139.0 rpm and 91% eff’cy ( specific speed =5.4), Are needed to exploit a head of 120 ft and a flow of 1660 ft^3/s.

A.2 turbines B.4 turbines

C. 3 turbines D. 5 turbines

How many poles should a 60-Hz generator have, if it is connected to a turbine operating under a design head of 3000 ft with a flow of 82 cfs? Assume turbine specific spped and eff’cy 3 and 84 pecent respectively.

A.10-pole B.14-pole

C. 12-pole D. 16-pole

It is proposed to build a dam in a river where the flow rate is 10 m^3/s and a 32-m drop in elevation can be achieved for flow through a turbine. If the turbine is 82 percent efficient, what maximum power that can be achieved? Specific gravity of river water is 0.998.

A.2570 KW B.3820 KW

C. 3133 KW D. 262 KW

What type of turbine delivers 25,000 BHP at 500 rpm under a net head of 5350 ft.

A. Impulse turbine B. Kaplan turbine C. Francis turbine D. Propeller turbine

A 26 HP pump delivers 475 gpm of gasoline (Y=42.5 lb/ft3) at 20oC with 78% efficiency. What pressure rise across the pump?

A.30.2 Psi B.120.3 Psi

C. 32.7 Psi D. 73.2 Psi

A model pump delivering water at 180oF (Y=60.6 lb/ft3; Pvapor= 7.54 Psia) at 900 gpm and 2,500 rpm begins to cavitate when the inlet pressure and velocity are 13 Psia and 22 fps. Find the required NPSH of a prototype which is 4 times larger and runs at 1,100 rpm.

A.63.5 ft B.6.61 ft

C. 20.49 ft D. 36 ft

The diameter of the discharge pipe is 8 in. and that of the intake pipe is 10 in. The pressure gage at discharge 32 Psi, and vacuum gage at the intake reads 12 in Hg. If the discharge flow rate= 4.0 ft3/s of water and the brake horsepower is 49.0, find the eff’cy. The intake and the discharge are at the same elevation.

A.82.1 % B.55.8 %

C. 80.9 % D. 58.46 %

A piston POSITIVE DISPLACEMENT-PUMP (PDP) has 6in diameter and 2.5-in stroke. Its crankshaft rotates at 300 rpm. Calculate its output at 94 percent volumetric eff’cy.

A.12.27 cfm B.10 cfm

C. 13.5 cfm D. 11.53 cfm

A centrifugal pumps (eff’cy 88%) lifts water trough a total height of 40 m from reservoir to discharge. Pumping is though 300 m of 75 mm diameter pipe at the rate of 20 liter/sec. If pipe friction factor, f= 0.025, what horsepower is required?

A.28.1 kW B.25 kW

C. 32.2 kW D. 9 kW

In order to predict the behavior of a small oil pump, tests are to be made on a model using air. The oil pump is to be driven by a 1/20-hp motor at 1800 rpm and ¼-hp motor Is available to drive the air pump at 600 rpm. Using specific gravity of oil at 0.912 and the density of air constant at 0.076 lb/ft^3, what size model should be built?

A. The model should be 2 times as large as the oil pump. B. The model should be 5 times as large as the oil pump. C. The model should be 8 times as large as the oil pump. D. The model should be 10 times as large as the oil pump.

A double-overhung impulse turbine installation is to develop 20,000 hp at 275 rpm under a net head of 1100 ft. determine the specific speed.

A.4.34 B.203.61

C. 6.14 D 144

An impulse wheel at best produces 125 hp under a head of 210 ft. by what percent should be speed be increased for a 290-ft head?

A.82.5 % B.72.41%

C. 17.5% D. 27.59%

What is the power ratio of a pump and its 1/5 scale model if the ratio of the heads is 4 to 1

A.20 B.12.5

C. 200 D. 125

The speed of a centrifugal pump is doubled. By the factor does the pump head change?

A.0.125 C. 0.25 B.4 D. 8

Determined the temperature for which a thermometer with degrees Fahrenheit is numerically twice the reading of the temperature in degrees Celsius.

A. -24.6 C. 160 B. 320 D. -12.3

During the takeoff in spaceship, an astronaut is subjected to acceleration equal to 5 times the pull of the earth’s standard gravity. If the astronaut is 180 lbm and the takeoff is vertical, what force does the seat?

A.4810.9 N B.4414.5 N

C. 8829 N D. 9620 N

A pressure cooker operates by cooking food at a higher pressure and temperature than is possible at atmospheric conditions.Steam is obtained in the sealed pot, with vent hole in the middle of the cover, allowing steam to escape. The pressure is regulated by covering the vent hole with a small weightwhich is displaced slightly escaping the steam.Atmospheric pressure is 100Kpa, the vent hole area is 7mm^2, and pressure inside should be 250Kpa.What is the mass of the weight?

A.0.107 kg B.1.05 kg

C. 1.75 kg D. 0.1783 kg

A barometer can be used to measure an airplane’s altitude by comparing the barometric pressureat a given flying altitude to that on the ground.Determine an airplane’s altitude if the pilot measures the barometric pressure at 700mm-Hg, the ground reports it at 758 mm-Hg, and the average air density is 1.19 kg/m3. g=9.8 m/s2.

A.987 m B.633 m

C. 788 m D. 663 m

A mixture of 0.4 LBm of helium and 0.2 LBm of oxygen is compressed polytropically from 14.7 psia and 60 deg F to 60 psia according to n=1.4.Determine the polytropic work.

A.139 Btu B.239 Btu

C. 339 Btu D. 539 Btu

A pump in a municipality’s water-supply system receives water from the filtration beds and pumps it up to the top of a water. The tower’s height is 35m, and the inlet piping in the pump is 2m below the pump’s intake. The water temperature is 20oC, measure at both the inlet and the discharge from the pump. The mass flow rate through the pump is 100kg/s, the diameter of the inlet piping is 25cm, and the diameter of the discharge piping is 15cm. Determine the power required by the pump.

A.77.3 Kw B.33.77 Kw

C. 34.42 Kw D. 42.34 Kw

A turbine receives 150 lbm/s of air at 63 Psia and 2,450 oR and expands it polytropically to 14.7 Psia. The exponent n is equal to 1.45 for the process. Determine the power.

A. 52,343.16 BTU/sec B. 53,343.16 KW C. 53,343.16 HP D. 53,343.16 ft-lb/s

An adiabatic tank containing air is used to power an air turbine during times of peak power demand. The tank has a volume of 500 m3 and contains air at 1000 Kpa and 500oK. Determine the mass remaining when the pressure reaches 100 Kpa. A.276.37 kg B.672.73 kg

C. 772.73 kg D. 227.73 kg

An adiabatic tank containing air is used to power an air turbine during times of peak power demand. The tank has a volume of 500 m^3 and contains air at 1000 Kpa and 500 deg. K. The temperature at this instant.

A. -14.03 o C B. 14.03 o K

C. 14.03 o F D. 14.03 o R

An otto cycle operates on 0.1 lb/s og air from 13 Psia and 130 deg. F at the beginning of the compression. The temp. at the end of combustion is 5000 deg. R; compression ratio is 5.5; hot air standard, k=1.3. Find the horsepower of the engine.

A.51.99 HP B.53.1 HP

C. 54.1 HP D. 55.1 HP

Determine the air-fuel ratio on a molar basis for the complete combustion of octane, with theoretical amount of air.

A. 59.5 kg air/kg fuel B. 95.5 kg air/kg fuel C. 69.5 kg air/kg fuel D. 49.5 kg air/kg fuel

During steady state operation, a gear box receives 60 KW through the input shafts and delivers power through the output shaft. For the gearbox as the system, the rate of energy transfer is by convection. h= 0.171 KW/m^2-K is the heat transfer coefficient, A= 1.0 m^2 is the outer surface area of the gearbox, Tb=300 deg. K (20 deg. C) is the temperature of the surroundings away from the immediate vicinity of the gearbox. Determine the power delivered to the output shaft in KW if the heat transfer rate is -1.2 KW.

A.98.8 KW B.78.8 KW

C. 68.8 KW D. 58.8 KW

A single acting air compressor with a clearance of 6 % takes in air at atmospheric pressure and temp of 85 deg. F, and discharges it at a pressure of 85 Psia. The air handled is 0.25 ft^3/cycle measured at discharge pressure. If the compression is isentropic, find the piston displacement per cycle, if the compressor is running at 750 rpm.

A.0.0750 ft3/cycle C. 1.030 ft3/cycle B.0.025 ft3/cycle D. 1.090 ft3/cycle

A single acting air compressor with a clearance of 6 % take in air at atmospheric pressure and temp. of 85 deg. F, and discharges it at a pressure of 85 Psia. The air handled is .25 ft^3/cycle measured at discharge pressure . If the compression is isentropic, Find the air HP of the compressor if rpm is 750.

A.16 HP B.96 HP

C. 69 HP D. 61 HP

A nozzle receives 0.5 kg/s of air at a pressure of 2700 kPa and a velocity of 30 m/s and with an enthalpy of 923 kJ/kg, and the air leaves at a pressure of 700 kPa, and with an enthalpy of 660 kJ/kg. determine the exit velocity from the nozzle.

A.923 m/s B.726 m/s

C. 700 m/s D. 660 m/s

How many hours would it take to boil down 1.2 kg of water in a kettle if a constant supply of heat at 1.25 kW is supplied to the kettle?

A.36 hrs B.52 hrs

C. 18 hrs D. 0.6 hrs

A 3.0 liter, 5-cylinder, 4 stroke cycle SI engine, with a volumetric efficiency of 82%, operates at 3000RPM using gasoline with a ʎ=0.91. bore and stroke are related as S = 1.08B. At a certain point in the engine cycle, the gas temperature in the combustion chamber is Tg = 2100oC while the cylinder wall temperature is Tw = 190oC. viscosity, and thermal conductivity, gases (air at 1145oC) Ug = 5.21x10-5 kg/m-sec , Kg= 0.090 W/m-K are respectively. Convective heat transfer coefficient of C1 = 0.035 and C2 = 0.08. calculate the approximate convection heat transfer rate to the cylinder wall at this instant.

A.54.32 kW/m2 B.32.54 kW/m2

C. 35.42 kW/m2 D. 45.44 kW/m2

A two – stage, double-acting compressor is to deliver 90 lb/min of air from 14.3psia and 90oF to final pressure of 185 psia. The normal barometer is 29.8in-Hg and the temperature is 80oF. the pressure drop in the intercooler is 3 psi and the speed is 210 rpm and pV1.34 = C during compression and expansion. The clearance is 5% for both cylinders. The temperature of the cooling water increase by 18oF. find the volume of free air.

A.1282 CFM B.1230 CFM

C. 1320 CFM D. 1822 CFM

A power plant has a steam operating header pressure of 150psig and saturated with engine exhaust at atmospheric pressure. Initial feed – water temperature is 65oF. what will be the fuel saving in percent if a feed – water heater is installed using exhaust steam and heating the water to 205oF? enthalpy of steam at header h = 1195.6btu/lb.

A.15.12 % B.12.04 %

C. 12.15 % D. 21.21 %

Consider 4800 lb of steam per hour flowing through a pipe at 100 psia pressure. Assume a velocity of 5280 ft/min. what size of pipe is required? Specific volume of steam 100 psia v=4.432 ft3/lb.

A.3 in B.5 in

C. 4 in D. 6 in

A boiler plant generates 225,000 lbs of steam and burns 13.9 tons of coal per hour. The coal has a heating value 11,400 BTU/lb. A test of the particulates leaving the boiler shows that 3,804 lb of particulate is being discharged per hour. What is the particulate discharged per million BTU heat input to the furnace?

A.12 lb/106 BTU B.14 lb/106 BTU

C. 15 lb/106 BTU D. 16 lb/106 BTU

A reciprocating compressor handles 1,400 cfm of air measured at the intake where P1= 18Psia and t1= 90oF. The discharge pressure is 92Psia. Calculate the work if the process of the compression is isothermal. A.-180.5 HP B.-179.5 HP

C. -227.6 HP D. -228.6 HP

The fuel oil has the ff: analysis; C= 89%, N2= 2%, H2= 8%, S= 1% with 3% excess air, what is the actual amount of air needed to burn the fuel oil? A. 13.17 kgair/kgfuel B. 13.47 kgair/kgfuel C. 14.47 kgair/kgfuel D. 14.17 kgair/kgfuel

A pump discharges 550 gpm of water to a height of 35 ft. With an eff’cy of 80%, What is the power input?

A.6.09 HP B.6.32 HP

C. 4.74 HP D.4.94 HP

A room contains air at 20oC and 96Kpa at a relative humidity of 75%. Determine the enthalpy of moist air where: (Psat at 20 oC= 2.339 Kpa) (hg at 20oC = 2538.1 kJ/kgda).

A.45.919 KJ/kgda B.45.515 KJ/kgda

C. 49.515KJ/kgda D. 41.815 KJ/kgda

A piston moves inside the cylinder at a velocity of 6.0bm/s. the 160 mm. diameter piston is centrically located within the 160.2 mm. inside diameter cylinder. The film of oil is separating the piston from the cylinder has an absolute viscosity of 0.4 N-s/m2. Assuming a linear velocity profile, find the shear stress in the oil. (T=ρ(v/H))

A.50,000 N/m2 B.40,000N/m2

C. 24,000 N/m2 D. 34,000 N/m2

A centrifugal pump with a 3 ft. impeller diameter operates at 800 rpm. If the speed is to be increased to 1200 rpm, determined the impeller diameter that should be used so that the same shaft input power would be required.

A.5.32 ft B.2.35 ft

C. 5.23 ft D. 2.93 ft

Determine the mass of water vapor contained in a 150 m^3 room at 100 Kpa, 23 deg.C and 40% relative humidity. From steam tables: [email protected] = 2.810 Kpa.

A.1.6342 kg B.1.2342 kg

C. 1.9342 kg D. 2.2342 kg

What is the power of the pump, HP, if it delivers 925 gal/min of water against a head of 15 m?

A.P = 15.38 HP C. P = 16.38 HP B.P = 10.5 HP D. P = 11.5 HP

Kerosene is pumped into an aircraft fuel tank through a hose that has an inside diameter of 4 cm. if the velocity of the kerosene is 8 m/s through the hose. Determine the mass flow rate. Assume that kerosene has a density of 800 kg/m3.

A.7.06 kg/s B.8.06 kg/s

C. 7.56 kg/s D. 8.56 kg/s

During experiment on Charles Law, the volume of gas trapped in the apparatus was 10000mm3 when the temperature was 18 oC. The temperature of the gas was then raised to 85 oC. Determine the new volume of gas trapped in the apparatus if the pressure exerted on the gas remained constant.

A.12302.41 mm3 B.70833.33 mm3

C. 8128.49 mm3 D. 2117.64 mm3

Specific volume of the number of cubic meters of mixture per kilogram of dry air. If dry air has these following properties: Ra = 287 J/kg.K, T = 303 K, Pa99.604 kPa. Solve for specific volume.

A.0.873 m3/kg B.0.9953 m3/kg

C. 0.853 m3/kg D. 0.783 m3/kg

At a pressure of 60oF, A motorbike tire is inflated to 33psig. As it is driven along the C-5 road, the temperature rise to 76oF. assuming the volume remains constant. Determine the final gauge pressure.

A.34.47 psig B.35.00 psig

C. 49.17 psig D. 34.30 psig

Steam enters a turbine stage with an enthalpy of 3700 KJ/kg and a velocity of 89 m/s and leaves with an enthalpy of 2864 KJ/kg with a velocity of 128 m/s, if the rate of a steam flow through the turbine if 0.44 kg/s, what is the work done in kW?

A.365 kW B.366.0 kW

C. 365.64 kW D. 366.5 kW

76. A car engine with a power output of 65 hp has a thermal efficiency of 24%. Determine the fuel consumption rate of this car if the fuel has a heating value of 19,000 Btu/ lb

A.36.28 lb/hr B.37.28 lb/hr

C. 37.28 lb/hr D. 35.30 lb/hr

77. Compute the humidity ratio of air at 70% relative humidity and 25oC when the barometric pressure is 101.325 Kpa. From steam tables: Psat @ 34oC = 3.169 Kpa

A.0.014 Kg water vapor / kg Dry Air B. 0.14 Kg water vapor / kg Dry Air C. 1.4 Kg water vapor / kg Dry Air D.0.0014 Kg water vapor / kg Dry Air

78. Consider 1 Kg of air at 32oC that expanded by a reversible polytropic process with n = 1.25 until the pressure is halved. Determine the heat transfer. Specific heat at constant volume for air is 0.1786 Kj/Kg - K

A. 17.02 Kj heat rejected C. 17.02 Kj heat added B. 7.05 Kj heat rejected D. 7.05 Kj heat added

79. A carnot cycle uses nitrogen (k = 1.399) as the working substance. The heat supplied is 54 kJ and the adiabatic expansion ratio is 10. Determine the heat rejected.

A.10 kJ B. 21.6 kJ

C. 32.4 kJ D. 54 kJ

80. A tank contains 20 kg of air at 200 kpa (gage) and 23oC. During heating process the temperature of air rises. For safety purposes, a technician installed a relief – type valve so that pressure of air inside the tank never exceed 260 kpa (gage). At what air temperature the relief valve will start releasing air?

A.112 oC B.82 oC

C. 92 oC D. 102 oC

81. An air compressor takes 9kg/min of air at 98kpa; v1=0.125 m3/kg. And discharges it at 680 kpa; v2 = 0.03 m3/kg. The increase of internal energy is 93 kJ/kg and the work done on air is 163 kJ/kg; the change in potential and kinetic energy are neglected. How much heat is transferred per kg of air?

A.264.15 B.288.65

C. 61.85 D. 78.15

82. During a reversible process there are abstracted 317 kJ/s from 1.134 kg/s of a certain gas while the temperature remains constant at 26.7oC. For this gas cp = 2.232 and cv = 1.713 kJ/kg-k. The initial pressure is 586 kPa. Determine the final volume flow rate.

A.0.301 m3/s C. 0.03 m3/s B. 0.5 m3/s D. 0.05 m3/s

83. An inventor claims to have developed a refrigeration unit which maintains the refrigerated space at 20oF within a room where the temperature is 80oF. He claims a coefficient of performance of at least 7.50. how do you evaluate his claim?

A. No data available to evaluate the claim B. Possible C. Impossible D. More observation are required

84. A 200 mm x 300 mm ammonia water cooled compressor at 1200 rpm receives refrigerant at 200 kPa, -10oC, h=1442 kJ/kg, 619.9 L/kg specific volume and is compressed to a final pressure and h=1759 kJ/kg, k of ammonia is 1.12. for a mass of 1kg/s of ammonia. Calculate the work of the compressor horsepower.

A.317 B. 713

C. 425 D. 524

85. A manufacturer of Carnot refrigerators has the choice of varying either the evaporator temperature, T 1=250K or the condenser temperature T2=500K by plus of minus 25K; no restrictions are placed on the operating temperatures. In the best interest of economy, what would you recommend to this manufacturer? A. Fix the temperature of condenser and increase the temperature of evaporator by 25K B. Fix the temperature of condenser and decrease the temperature of the evaporator by 25K C. Fix the temperature of evaporator and increase the temperature of the condenser by 25K D. Fix the temperature of evaporator and decrease the temperature of the condenser by 25K

86. A creamery must cool 40,000liters of milk received each day from initial temperature of 20oC to final temperature of 2oC in 10 hours. If refrigeration losses amount to 30% of the cooling load what must be the capacity of the refrigerating machine if the specific heat of milk is 0.93 Btu/lb-R and SG = 1.15.

A.33 TR C.38 TR

B.43 TR D.48 TR

87. A refrigeration system produces 250 Btu/lb of cooling. In order to have a rating of one ton of refrigeration, what mass of refrigerant shall be used in the refrigeration system?

A.1152 lb/day B. 180 lb/day

C. 1920 lb/day D. 360 lb/day

88. Express ten tons of refrigeration in CHU/hr A.840 B. 2257

C. 970.3 D. 66,666.67

89. A standard vapor compression refrigeration system requires a compressor work of 5kW. The condenser releases 15 kJ/s of heat. Determine the amount of air to be conditioned if the decrease in enthalpy at the air conditioning unit is 50kJ/kg. A.0.40 B. 0.60

C. 0.20 D. 0.80

90. The refrigerant load of vapor compression refrigeration system is 50kJ/kg. the COP is 6. the enthalpy of the refrigerant leaving the compressor is 85 kJ/kg. determine the enthalpy entering the compressor. A.72 kJ/kg B. 83 kJ/kg

C. 77 kJ/kg D. 88 kJ/kg

91. A 3 – hp refrigerator of heat pump operates between 0oF and 100oF. The maximum theoretical heat that can be transferred from the hot reservoir is nearest to A.76,000 Btu/hr B. 23,000 Btu/hr

C. 13,000 Btu/hr D. 43,000 Btu/hr

92. What is the enthalpy of a refrigerant entering the compressor in kJ/kg if the COP of the refrigeration system is 4.80 and the compressor work is 207.30 kJ/kg? The enthalpy at the entrance of the evaporator is 58.20 kJ/kg. A.1035.24 kJ/kg B. 1520.42 kJ/kg

C. 1043.25 kJ/kg D. 1053.24 kJ/kg

93. A refrigeration system operates on an ideal vapor compression using R-12 with a saturated temperature -1.1oC (hg=351.003 kJ/kg) and a liquid R-12 temperature at 30oC ( hf=288.54 kJ/kg). What is the mass flow rate of the refrigerant if the refrigerating capacity is 1.776 TR in kg/s?

A.0.40 kg/s B. 0.20 kg/s

C. 0.30 kg/s D. 0.10 kg/s

94. Ten gallons per minute of cooling water undergo an 8oC temperature rise during passage through a shell and tube condenser. If the refrigerant flow rate is 3 kg/min and the tons of refrigeration is 5.15, what is the work of isentropic compression in kJ/kg?

A.40 B.70

C. 60 D. 80

95. A businessman after feasibility study found out that the ice consumption of his locality to be 48,000 kg of ice per day. He wants to manufacture ice at -10oC from water available at 25oC. Determine the capacity of the compressor in hp.

A.207 B.107

C. 80 D. 90

96. In a process carried out on a closed system, the work transferred into the system was 4200kJ and the increase in the total energy of the system was 3500kJ. Determine the heat transferred.

A.-700 B.-7700

C. 7700 D. 700

97. Determine the atmospheric pressure at a location where the barometric reading is 740mm hg and the gravitational acceleration is g=9.81m/s2. Assume the temperature of mercury to be 10oC, at which its density is 13,570 kg/m3.

A.99.7 kPa B.101.325 kPa

C. 98.5 kPa D. 97.5 kPa

98. A fluid in a cylinder is at a pressure of 700N/m2. It is expanded at a constant pressure from a volume of 0.28m3. Determine the work done.

A.960 kJ B. 955 kJ

C. 1000 kJ D. 980 kJ

99. An iron block weighs 7 newtons and has a volume of 200 cubic centimeters. What is the density of the block?

A.3465 kg/m3 B. 3565 kg/m3

C. 1255 kg/m3 D. 2550 kg/m3

100. If the density of the gas is 0.003 slugs per cubic foot. What is the specific weight of the gas ?

A.9.04 N/m3 B. 15.2 N/m3

C. 76.3 N/m3 D. 98.2 N/m3

101. The specific gravity of mercury relative to water is 13.55. what is the specific weight of mercury? ( the specific weight of water is 62.4 lbf per cubic foot)

A.82.2 kN/m3 B. 102.3 kN/m3

C. 132.9 kN/m3 D. 150.9 kN/m3

102. If the specific weight of a liquid is 58.5 lbf per cubic foot, what is the specific volume of the liquid?

A.0.5321 cm3/g B. 0.6746 cm3/g

C. 0.9504 cm3/g D. 1.0675 cm3/g

103. Which of the following are not units of pressure?

A.Pa B.bars

C. kg/m-s2 D. kg/m2

104. A cylinder weighs 150 lbf. Its cross sectional area is 40 square inches. When the cylinder stands vertically on one end. What pressure does the cylinder exert on the floor?

A.14.1 kPa B. 25.8 kPa

C. 63.2 kPa D. 89.7 kPa

105. What pressure is a column of water 100 centimeters high equivalent to?

A.9810 dyne/cm2 B. 9810 N/m2

C. 0.1 bars D. 0.1 atm

106. Water is flowing in a pipe with a radius of 10” at a velocity of 5 m/s. At the temperature in the pipe, the density and viscosity of the water are as follows: ρ = 997.9 kg/m3 µ = 1.131 Pa-s. what is the Reynold’s number for this situation?

A.44.1 B. 88.2

C. 1140 D. 2241

107. What is the flow rate through a pipe 4” in diameter carrying water at a velocity of 11ft/s?

A.27,200 cm3/s C. 993 cm3/s B. 726 cm3/s D. 19, 200 cm3/s

108. How long must be a current of 5.0 amperes pass through a 10 ohm resistor until a charge of 1200 columbs passes through?

A.1 min B. 2 min

C. 3 min D. 4 min

109. A car moving at 70 km/hr has a mass of 1700 kg. what force is necessary to decelerate it at a rate of 40 cm/s2.

A.0.680 N B.42.5 N

C. 680 N D. 4250

110. One hundred millimeters of water in a plastic bag of negligible mass is to be catapulted upwards with an initial acceleration of 20.0 m/s2. what farce is necessary to do this? Assume the gravity is 9.81 m/s2 and the density of water is 1g/cm3 A. 2.00 N B. 2.98 N

C. 15.0 N D. 2.00 kN

111. A boy pulls a sled with a mass of 20kg horizontally over a surface with a coefficient of friction of 0.20 . It takes him 10 minutes to pull the sled 100 yards. What is his average power output over these 10 minutes? A. 4 W B. 6 W

C. 8 W D. 10 W

112. A force of 200 lbf acts on a block at an angle of 28o with respect to horizontal. The block is pushed 2 feet horizontally. What is the work done by this force? A. 215 J B. 320 J

C. 480 J D. 540 J

113. Two particles collide. Stick together, and continue their motion together. Each particle has a mass of 10g, and their respective velocities before the collision were 10 m/s and 100 m/s. what is the energy of the system after the collision?

A. 21.8 J B. 30.2 J

C. 42.8 J D. 77.9 J

114. Two protons, each of charges 1.6 x 10-19 coulomb, are 3.4 micrometers apart. What is the change in the potential energy of the protons if they are brought 63 nanometers closer together?

A. 6.4 x 10-29 J B. 7.16 x 10-24 J

C. 1.28 x 10-24 J D. 3.21 x 10-24 J

115. A copper bar is 90 centimeters long at 86oF. What is the increase in its length when the bar is heated to 95oF? The linear expansion coefficient for copper is 1.7 x 10-5 /oC

A. 2.12 x 10-5 m B. 3.22 x 10-5 m

C. 5.25 x 10-5 m D. 7.65 x 10-5 m

116. A slab of iron with temperature, Ti1=48oC is used to heat a fat glass plate that has an initial temperature of T g1=18oC. Assuming no heat is lost to the environment, and the masses are m i=0.40kg for the slab and mg=310g for the plate. What is the amount of heat transferred when the two have reached equal temperatures? Assume ci=0.11 kcal/kg-oC for iron and cg=0.20 kcal/kg-oC for glass.

A. 860 cal B. 32 kcal

C. 53 kcal D. 320 kcal

117. Calculate the energy transfer rate across a 6” wall of firebrick with a temperature difference across the wall of 50oC. The thermal conductivity of firebrick is 0.65 BTU/hrft-oF at the temperature of interest.

A. 112 W/m2 B. 285 W/m2

C. 369 W/m2 D. 429 W/m2

118. A house has brick walls 15 millimeters thick. On a cold winter day, the temperature of the inner and outer surfaces of the walls are measured and found to be 20oC and -12oC, respectively. If there is 120m2 of exterior wall space, and the thermal conductivity of bricks is 0.711 J/ms-oC, how much heat is lost through the walls per hour? A. 182 J B. 12.5 kJ

C. 655 kJ D. 655 MJ

119. Air has a specific heat of kJ/kg-K. If 2 BTU of energy is added to 100 g of air, what is the change in air temperature?

A. 10.0 oC B. 21.1 oC

C. 44.1 oC D. 88.2 oC

120. Air has specific heat (cp) of 1kJ/kg-K. if 100 g of air are heated with 1500 W heater, which of the following occurs? I. The air heats up at a rate of 15K/s II. The air reaches a final temperature of 15000 K III. The air undergoes a non-isentropic process A. I only B. I and II

C. I, II, and III D. I and III

121. The change of enthalpy of an incompressible liquid with constant specific heat is given by: h2 - h1 = c(T2 - T1) = _(P2 – P1)

Where: Tn= temperature at a state, nPn= pressure at state, nv = specific volume of the liquid

Water with cp = 4.18 kj/kg –K and v = 1.00 x 10-3 m3/kg has the following final states: State I: T1=19oC p1=1.013 x 105 Pa State II: T2=30oC p2=0.113 Mpa What is the change in enthalpy from state I to state II?

A. 46.0 kJ/kg B. 46.0 kN/kg

C. 46.0 kPa/kg D. 56.0 kJ.kg

122. In a constant temperature, closed system process, 100 BTU of heat is transferred to the working fluid at 100oF. What is the change in entropy of the working fluid?

A. 0.18 kJ/K B. 0.25 kJ/K

C. 0.34 kJ/K D. 0.57 kJ/K

123. If a 1/3 horsepower pump runs for 20 minutes, what is the energy used?

A. 0.06 ergs B. 0.25 kW

C. 0.30 MJ D. 0.11 kW - hr

124. A machine is capable of accelerating a kg mass at 1 m/s2 for 1 minute. The machine runs at 60 rpm. What is the power output of the machine?

A. 1 erg B. 1 cal

C. 1 J D. 1 W

125. A power of 6 kW is supplied to the motor of a crane. The motor has an efficiency of 90%. With what constant speed does the crane lift an 800lbf weight?

A. 0.09 cm/s B. 0.32 cm/s

C. 0.98 cm/s D. 1.52 cm/s

126. An engine has an efficiency of 26%. It uses 2 gallons of gasoline per hour. Gasoline has a heating value of 20,500 BTU/lbm and a specific gravity of 0.8. what is the power output of the engine?

A. 0.33 kW B. 20.8 kW

C. 26.0 kW D. 41.7 kw

127. Two liters of an ideal gas, at a temperature of Ti=25oC and a pressure of Pi=0.101 Mpa, are in a 10cm diameter cylinder with a piston at one end. The piston is depressed, so that the cylinder is shortened by 10 centimeters. The temperature increases by 2oC. What is the change in pressure? A. 0.156 MPa B. 0.167 MPa

C. 0.251 MPa D. 0.327 MPa

128. The average power output of a cylinder in a combustion engine is given by: P=pLAN p=average pressure on the piston during the stroke L=length of piston stroke A=area of the piston head N=number of strokes per second An 8 cylinder engine has the following specifications at optimum speed: p=283kPa, L=14cm, d=diameter of piston head = 12cm, N=1500 strokes/min. what is the average power output of this engine? Where:

A. 89.5 N/s B. 89.5 kW

C. 89.5 x103 J-m/s D. 89.5 kJ

129. What is the power required to transfer 97,000 coulombs of charge through a potentials rise of 50 volts in one hour?

A. 0.5 kW B. 0.9 kW

C. 1.3 kW D. 2.8 kW

130. A current of 7 amperes passes through a 12 ohm resistor. What is the power dissipated in the resistor?

A. 84 w B. 0.59 hp

C. 0.79 hp D. 7 hp

131. If the average energy in a nuclear reaction is 200 MeV/fission, what is the power output of a reactor if there are 2.34 x 1019 fission per second?

A. 550 W B. 120 kW

C. 30 MW D. 750 MW

132. A surface tension force, σ , of water in air is approximately 0.00518 lbf/ft. if the atmospheric pressure is 14.7 psi, what is the pressure inside a droplet 0.01” in diameter?

A. 14.53 psia B. 14.70 psia

C. 14.87 psia D. 14.78 psia

133. What is the pressure at point A in the tank if h=2 feet? (g=32.3 ft/sec2, and p=1.94 slug/ft3)

A. 75 lbf/ft2 B. 85 lbf/ft2

C. 100 lbf/ft2 D. 125 lbf/ft2

134. Determine the average velocity through a circular section in which the velocity distribution is given as v = vmax. The distribution is symmetric with respect to the longitudinal axis, r=0. ro is the outer radius, vmax is the velocity along the longitude axis.

A. B.

C. D.

135. A pipe has a diameter of 4” at section AA, and a diameter of 2” at section BB. For an ideal fluid flow, the velocity is given as 1ft/sec at section AA. What is the flow velocity at section BB?

A. 4 ft/sec B. 0.5 ft/sec

C. 1.0 ft/sec D. 2.0 ft/sec

136. A mixing tank mixes two inlet streams containing salt. The salt concentration in stream 1 is 5% by weight, and stream 2 is 15% by weight. Stream 1 flows at 25 kg/s, and stream 2 flows at 10 kg/s. there is only one exit stream. Find the salt concentration in the exit stream. A. 5% B. 8%

C. 11% D. 13%

137. Water is pumped at 1 m3/s to an elevation of 5 meters through a flexible hose using a 100% efficient pump rated at 100 kW. Using the same length of hose, what size motor is needed to pump 1 m3/s of water to a tank with no elevation gain? In both cases both ends of the hose are at temperature pressure. Neglect kinetic energy effect. A. 51 kW B. 22 kW

C. 36 kW D. 43 kW

138. What is the actual volumetric flow rate for the discharge of the tank shown? The coefficient of contraction for the orifice is 0.61, and the coefficient of velocity is 0.98

A. 6.78 ft3/s B. 6.92 ft3/s

C. 9.79 ft3/s D. 11.34 ft3/s

139. The upper plate is fixed, while the lower plate moves in the positive x direction at 0.5 m/s. The plate separation is 0.001m, the fluid viscosity is 0.7cp and the velocity profile is linear. Calculate the shear stress Txv in the moving fluid.

A. 0.05 Pa B. 0.15 Pa

C. 0.25 Pa D. 0.35 Pa

140. Calculate the Reynolds number, Re, for water at 20oC flowing in an open channel. The water flowing at a volumetric rate of 200 gal/sec. the channel has a height of 4 feet and a width of 8 feet. At this temperature, water has a kinetic viscosity of 1.04 x 105 ft2/sec.

A. 600,000 B. 800,000

C. 1.0 x 106 D. 1.2 x 106

141. A fluid with a kinetic viscosity of 2.5 x 10-5 ft2/sec is flowing at 0.1 ft/sec from an orifice 3” in diameter. How can the fluid be described?

A. The fluid is completely turbulent B. The fluid is laminar C. The fluid is in transition zone D. Turbulent cannot be calculated; it must be measured

142. The Reynolds number of a sphere falling in air is 1 x 106. If the spheres radius is 1 ft, what is its velocity? (ρair=0.00234

slug/ft3, µair=3.8 x 10-7 lb-sec/ft2)

A. 2.5 ft/sec B. 5.1 ft/sec

C. 40.6 ft/sec D. 81.2 ft/sec

143. From the Blasius solution for laminar boundary layer flow, the average coefficient of skin friction is : If air flowing past a 33 feet long plate at a velocity of 100 ft/sec, what is the force on the plate?

A. 0.00114 lbf B. 0.00344 lbf

C. 0.086 lbf D. 0.114 lbf

144. The flow rate of water through a cast iron is 5000 gallons per minute. The diameter of the pipe is 1 foot, and the coefficient of friction is ƒ = 0.0173. What is the pressure drop over a 100 foot length of pipe?

A. 21.078 lbf/ft2 B. 23.78 lbf/ft2

C. 337.26 lbf/in2 D. 337.26 lbf/ft2

145. A cast iron pipe of equilateral triangular cross section with side length of 20.75” has water flowing through it. The flow rate is 5000 gallons per minute, and the friction factor for the pipe is ƒ = 0.017. what is the pressure drop in a 100 foot section?

A. 24.3 lbf/ft2 B. 48.7 lbf/ft2

C. 178.5 lbf/ft2 D. 309.7 lbf/ft2

146. A circular cylinder 4 feet long and 3 feet in diameter is in air stream. The flow velocity is 5 ft/sec perpendicular to the axis of the cylinder. Given that the coefficient of drag, CD, on the cylinder is 1.3, and the density of air is 0.00234 slug/ft3, what is the force on the cylinder?

A. 0.09 lbf B. 0.11 lbf

C. 0.46 lbf D. 0.91 lbf

147. Air flows past a 2 diameter sphere at 100 ft/sec. What is the drag force experienced by the sphere given that it has a coefficient of drag of 0.5 and that the density of the air is 0.00234 slug/ft3?

A. 0.041 lbf B. 0.064 lbf

C. 0.128 lbf D. 0.244 lbf

148. A cylinder 10 feet long and 2 feet in diameter is suspended in air flowing at 8ft/sec. the density of air is 0.00234 slug/ft3, and the coefficient of drag of the sphere is 1.3. what is the drag on the cylinder?

A. 0.311 lbf B. 0.39 lbf

C. 1.95 lbf D. 3.89 lbf

149. A coil has an inlet temperature of 70oF and outlet of 80oF. If the mean temperature of the coil is 130oF, find the bypass factor of the coil.

A. 0.28 B. 1.20

C. 0.82 D. 0.83

150. Compute the pressure drop of 35oC air flowing with a mean velocity of 5 m/s in a circular sheet-metal duct 400mm in diameter and 25m long. Use a friction factor, f=0.04 and ρair=1.3799 kg/m3.

A. 431.22 Pa B. 221.34 Pa

C. 312.24 Pa D. 422.31 Pa