Coaching 150 Pipe Up

The refrigerant 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 33 L/s. determine the volumetric efficiency of the compressor.

A. 77.65 % B. 87.6 % C. 97.6 TR D. 65.65 %

The 600 kg hammer of a pile drive is lifted 2 meters above the piling head. If the hammer is released, what will be its velocity at the instant its strikes the the piling head g = 9.65 m/s². A. B. C. D.

6.21 m/s 3.25 m/s 1.2 m/s 4.5 m/s

Compute the humidity ratio of air at 70% relative humidity and 25˚C when the barometric pressure is 101.325 kpa. From steam tables: Psat 34 0C = 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 vapor /kg dry air

Calculate the thermal diffusivity of pure aluminum with density of 2,702 kg/m3, thermal conductivity of 237 W/m.K and specific heat of 0.903 kJ/kg.K

A. 97.1 x 10-6 m2/s B. 23.25 x 10-6 m2/s C. 14.9 x 10-6 m2/s D. 34.5 x 10-6 m2/s

A pressure gage registers 50 psig in a region where the barometer reads 14.8 psia. Find the absolute temperature in kpa. A. B. C. D.

666.66 kpa 556.66 kpa 446.66 kpa 336.66 kpa

A new temperature scale is to be used where freezing and boiling temperature of water is at 290(500) deg N and 100 deg N respectively. Calculate the absolute zero temperature in deg N. A. B. C. D.

-992.6 deg N -932.7 deg N -995.6 deg N -932.4 deg N

Consider 1 kg of air at 32 deg C that expanded by reversible polytropic process with n = 1.25 and the pressure is halved. Determine the heat transfer specific heat at constant volume for air is 0.378 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

An elastic sphere containing gas at 120 kpa has a diameter of 1.0 m. Heating the sphere caused 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. B. C. D.

143.91 KJ 200.7 KJ 154.5 KJ 133.91 KJ

Fifty kilograms of cooling water per second enters the condenser at 25 deg C and leaves at 50 deg C. Find the heat carried away by the water. A. B. C. D.

1234.45 KW 5233.75 KW 2340.53 KW 3140.25 KW

Ten kilograms per second of steam enters the turbine with an enthalpy of 3200 KJ/kg and enter the condenser with an enthalpy of 2500 KJ/kg. in a Rankine cycle. If the turbine efficiency is 80% and generator efficiency is 90%. Determine the power plant output . A. B. C. D.

4320 KW 3213 KW 4056 KW 5040 KW

Air is used in a Carnot engine where the volume at the beginning of the constant temperature heat addition and end of the constant temperature heat rejection are 0.456 cm3 and 6.73 cm3, respectively. Calculate the thermal efficiency

A. 0.667 B. 0.656 C. 0.786 D. 0.765

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

A. 100% B. 20% C. 80% D. 60%

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 298.15 K.

A. 17.38 kN B. 5.28 kN C. 18.73 kN D. 8.25 kN

The condenser of a reheat power plant rejects heat at the rate of 600 kW. The mass flow rate of cooling water is 5 kg/s and the inlet cooling water temperature is 35C. Calculate the condenser cooling water exit temperature.

• • • •

A. 43.45 C B. 53.45 C C. 63.66 C D. 74.34 C

The filament of a 100 W bulb maybe considered a blackbody radiating into a black enclosure 80 deg. C. Considering only radiation calculate the filament temperature in deg. C. If the filament diameter is 0.1 mm and the length is 6 cm.

A. 3109.97 oC B. 2837 oC C. 3245.45 oC D. 2313.9 oC

A heat engine has a thermal efficiency of 50%. How much power does the engine produce when heat is transferred at a rate of 10⁶ KJ/ hr (109 J/hr)? A. B. C. D.

50 MW 75 MW 139 MW 147 MW

A circular chip ( k = 150 W/ m K ) with a diameter of d = 10 mm and thickness of 4 mm is embedded in a circuit board. Its front surface is exposed to the flow of coolant ( h= 250 W/m² K ) with temperature of 10 deg C, while its side and black surfaces are perfectly insulated. If at any point in the chip the temperature must not exceed 90 deg C, what is the steady state heat dissipation of the chip?

A. B. C. D.

2.06 W 1.56 W 2.01 W 1.74 W

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

• • • •

A. 212 kJ/kg B. 100 kJ/kg C. 0 kJ/kg D. 331.25 kJ/kg

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

-0.245 -0.49 -0.631 -0.546

Three hundred kilojoules of heat flow by conduction from the outside to the inside of cold storage in one hour. If the temperature and all other conditions are the same, what is the heat flowing through the storage room in 2 hours? A. B. C. D.

600 KJ 900 KJ 300 KJ 1200 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. B. C. D.

0.942 0.456 0.765 0.673

Determine the sp.heat weight of air at 760 mmHg absolute and 22C?

A. 1.014 kg/m3 B. 1.316 kg/m3 C. 1.197 kg/m3 D. 1.266 kg/m3

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

Find the enthalpy of the helium if its internal energy is 200KJ/Kg.

A. 144 kj/kg B. 223.42 KJ/kg C. 333.42 KJ/kg D. 168 KJ/kg

If the conditioned space receives 80,000 kg of air per hour and air supply temperature rises about 10oC and air picks up latent heat about 150 kW, determine the sensible heat factor of the system.

A. 0.597 B. 0.554 C. 0.612 D. 0.509

Compute the mass of a 2 cubic meter propane at 280 kpa and 40 ˚C. A. B. C. D.

6.47 kg 3.1 kg 10.20 kg 9.47 kg

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

60 62.43 61.54 50

Compute the air flow in cu. ft per 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

An amount of air with DB temperature of 35˚ C. With the temperature 28˚ C is passed through an air conditioner and exhaust at a DB Temperature of 24˚C and RH 0f 50%. Cooling coil temperature is approximately 18 ˚C. Determine the bypass factor of the air conditioning. A. B. C. D.

0.69 0.43 0.26 0.35

Compute the free aperture cross section in m^2 for the ventilation of a machinery room in the mass of refrigerant is 9kg.

A. 0.314 B. 0.414 C. 0.514 D. 0.614

A commercial air conditioner is rated by means of EER or energy efficiency ratio. For a certain air conditioner 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

A 29.53” x 39.37” 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

The cooling water leaves the condenser at 60 ˚C and leaves the cooling tower at 35 ˚C. The ambient air is at 35 ˚C DB and 28 ˚C WB. Determine the cooling tower efficiency. A. B. C. D.

41.67 80 78 53.33

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

0.286 ft 0.386 ft 0.486 ft 0.583 ft

A 6-stage centrifugal pump delivers 1600 gpm of water against a net pressure rise of 800 lbf/in2. What is the specific speed if it rotates at 1750 rpm.

A. 248.54 rpm B. 952.82 rpm C. 1020 rpm D. 546.23 rpm

A thermal power plant has a heat rate of 11,363 Btu/kw-hr. find the thermal efficiency of the plant. A.28% B.30% C.34% D.40%

The suction pressure of 4 stage compressor is 140 kpa. It compresses air at the rate of 15 m3 , clearance is about 8% and 200 rpm. The compressor discharges compressed air at a pressure of 1000 Kpa. If the compressor uses intercooling, determine the ideal pressure at the first stage intercooler. A. B. C. D.

228.87 Kpa 345.67 Kpa 453.45 Kpa 345.45 Kpa

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

A. 5.10m B. 10.2m C. 17.4m D. 2.55m

Find the COP of the refrigerator whose energy supply equals one-fourth the amount of heat it extracts.

A. 3 B. 4 C. 5 D. 2

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

A. 3543.75 B. 3513.75 C. 3563.75 D. 3593.75

kg/hr kg/hr kg/hr kg/hr

An air conditioning engineer has given the following data to be air conditioned; room sensible heat gain 10,000(50000) Btu/hr. Outside room latent heat gain 10,000 Btu/hr. Outside conditioned 95% of DB & 75 ˚F WB, inside condition 50 ˚F. Calculate the refrigeration tonnage required with 10% safety factor. A. B. C. D.

5.5 3.5 1.5 6.5

Copra enters a dryer containing 70% moisture and leaves at 7% moisture. Find the moisture removed on each pound of solid in final product. A. B. C. D.

6.258 lb 1.258 lb 4.258 lb 2.258 lb

If the specific heat at constant pressure for C0₂ is given as 0.201 Btu/lb ˚R, what is the value of the specific heat at constant volume? A. B. C. D.

0.156 Btu/lb ˚R 0.365 Btu/lb ˚R 0.435 Btu/lb ˚R 0.435 Btu/lb ˚R

A 1 m x 1.5 m cylindrical tank full of oil with SG = 0.92. Find the force acting at the bottom of the tank in dynes. A. B. C. D.

106.33x10⁷ dynes 106.33x10⁵ dynes 106.33x10⁴ dynes 106.33x10⁶ dynes

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

A. 2.89 B. 3.24 C. 1.34 D. 3.21

Find the pressure at the 100 fathom depth of water in kpag.

A. 1,793.96 B. 1,893.96 C. 1,993.96 D. 1,693.96

kpag kpag kpag kpag

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

A. 320 B. 332 C. 341 D. 361

Find the depth in furlong at the ocean (SG= 1.03) if the pressure at the sea below is 2032.56 kpag. A. B. C. D.

1 2 3 4

A Pelton Wheel running at 400 rpm is driven by a water power of 5000 kW. The elevation is 150 m and the velocity coefficient is f = 0.97. Find the number of jets required if its diameter is limited at 0.15m.

A. 3 B. 4 C. 5 D. 6

Find the mass of ten quarts of water. A. B. C. D.

10.46 kg 9.46 kg 11.46 kg 8.46 kg

A potential waterfall for hydroelectric power plant has water available at a rate of 160 m3/s under a head of 18 m. Find the number of Francis turbines required if it runs at 120 rpm, specific speed of 350 and hydraulic efficiency of 80%.

A. 3 turbines B. 2 turbines C. 5 turbines D. 4 turbines

Find the mass of carbon dioxide having a pressure of 20 psia @ 200 F with 10 ft3 volume. A. B. C. D.

1.04 lbs 1.14 lbs 1.24 lbs 1.31 lbs

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

A. 5.14 B. 5.13 C. 5.82 D. 5.32

Find the heat needed to raise the temperature of water at 30deg C to 100deg C with 60% quality. Consider an atmospheric pressure of 101.325 kpa. Use the approximiate enthalpy of liquid. A. B. C. D.

293.09 KJ/kg 1773.90 KJ/kg 1547.90 KJ/kg 1647.29 KJ/kg

A Pelton wheel running at a speed of 600 rpm is driven by 2 similar jets. At this speed, is transmit 6000 kW to the shaft. The efficiency of the runner is 90% and the velocity of the fluid at inlet to the bucket is 50 m/s, estimate the diameter of each jet.

A. 0.0165 m B. 0.0435 m C. 0.0143 m D. 0.0123 m

An air compressor consumed 1200 kw-hr/day of energy. The electric motor driving the compressor has an efficiency of 80%. 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 steam generator operating at 92% efficiency leaves water at 15.6 ˚C while steam leaves the superheater at h = 3374.8 KJ/kg. Estimate the evaporation factor if the boiler consumes coal of calorific value 24,500 KJ/kg. A. B. C. D.

6.81 m 6.72 m 8.21 m 7.21 m

A refrigeration system consumed 28,800 KW-hr per month of energy. There are 20% of energy is lost 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

Calculate the available pressure head for natural circulation of a 10-m riser if specific volume at the downcomer is 0.0014 m3/kg and at the riser top is 0.0032 m3/kg.

A. 19.71 kPa B. 12.45 kPa C. 21.45 kPa D. 15.74 kPa

A 200 mm x 250 mm, 8 cylinder, 4 strokes diesel engine has brake power of 150 KW. The mechanical efficiency is 80%. If two cylinders 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

Estimate the circulation ratio in the downcomer riser circuit when the mass of saturated water flowing through it is 10 kg/s while at the riser exit saturated liquid water flows at 8.5 kg/s. A. B. C. D.

1.18 6.67 5.9 0.85

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

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 liquid is 20, Estimate the slip ratio. A. B. C. D.

1.48 1.67 1.74 1.32

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

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

83.25% 76.25% 87.45% 80.76%

What is the approximate value of temperature of water having enthalpy of 208 Btu/lb? A. B. C. D.

138.67 ˚C 115.55 ˚C 258.67 ˚C 68.67 ˚C

What is the overall efficiency of a 30 MW steam power plant with a boiler efficiency of 92%, cycle efficiency of 44%, mechanical loss of 5%, generator efficiency of 93% and gross power production 32,000 KW. A. B. C. D.

33.98% 36.88% 35.44% 38.84%

An Otto cycle has compression ratio of 8. Find the pressure ratio during compression. A. B. C. D.

18.38 16.38 14.38 12.38

A downcomer riser circuit receives saturated water at a rate of 10.5 kg/s from the boiler. If the circulation ratio is 11.5, what is the top dryness fraction. A. B. C. D.

0.095 0.067 (0.087) 0.081 0.913

A Diesel cycle has a cut off ratio of 2.5 and expansion ratio of 4. find the clearance of the cycle. A. B. C. D.

9.11% 5.55% 11.11% 15.15%

A rectangular duct section 35 cm x 50 cm in size carries 75 m3/min of air having density of 1.15 kg/m3. Determine the equivalent diameter of circular duct if the quantity of air carried in both cases is the same.

A. 0.26 B. 0.36 C. 0.46 D. 0.56

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

A. 3638.50 B. 3365.50 C. 3565.50 D. 3965.50

deg deg deg deg

C C C C

A rectangular duct section 35cm X 50cm size carries 75m3 /min of air having density of 1.15 kg/m3 . If the friction factor of sheet metal is 0.01, find the pressure loss per 100m length of duct. A. B. C. D.

29mm of H20 36mm of H20 25mm of H20 35mm of H20

A three stages air compressor compresses air from 100kpa to 1000kpa. Find the intercooler pressure between the first and second stage.

A. 505.44kpa B. 108.44kpa C. 316.23kpa D. 215.44kpa

A Rectangular duct .15m and .12m long carries a standard air at the rate of .3 m3 /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. 761.58 B. 671.85 C. 851.67 D. 716.58

N/m2 N/m2 N/m2 N/m2

A 10—stages air compressor compresses air from 100kpa to 800kpa. Find the intercooler pressure between the first and second stage.

A. 282.84 B. 113.21 C. 123.11 D. 333.51

kpa kpa kpa kpa

A circular duct if 40-cm is selected to carry air in an air conditioned 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. 45 cm x 30 cm B. 40 cm x 25 cm C. 50 cm x 35 cm D. 30 cm x 15 cm

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

A. 365.88 B. 375.88 C. 385.88 D. 395.88

kpa kpa kpa kpa

A galvanized steel duct of 0.4 diameter and 20oC and 1.013 bar. If the surface roughness for the duct is 0.15 mm, find the roughness factor.

A. 0.000475 B. 0.000365 C. 0.000375 D. 0.000485

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

A. 111.44 B. 549.78 C. 247.53 D. 141.89

kw kw kw kw

A Reverse Carnot cycle air conditioner of 4TR capacity operates with a cooling coil of temperature of 5deg 0C. The surrounding air at 45deg 0C is used as a cooling medium rising to the temperature of 55 deg 0C. The temperature of heat rejection is 60 deg 0C. Determine the mass flow rate of air entering the heat exchanger.

A. 0.07 kg/s B. 0.12kg/s C. 0.16 kg/s D. 0.04 kg/s

Two kilogram of air in a rigid tank changes its temperature from 32oC to 150oC. Find the work done during the process.

A. 236 B. 170 C. 195 D. 0

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

99.45 kpa 97.41 kpa 95.44 kpa 98.66 kpa

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

A. 2.45 TR B. 1.86 TR C. 2.06 TR D. 1.26 TR

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. B. C. D.

1274.21 m 1289.00 m 1267.34 m 1583.34 m

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

0.66 0.55 0.77 0.88

The lower half of a 10 m high cylindrical container is filled with water and the upper half with oil that has S.G. = 0.85. Determine the pressure difference between the top and the bottom of the cylinder. A. B. C. D.

90.74 kpa 92.74 kpa 83.36 kpa 96.20 kpa

About 3 Hp per ton is required to maintain a temperature of -40 ˚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. B. C. D.

69.72 Kcal/min 70.44 Kcal/min 81.61 Kcal/min 84.65 Kcal/min

An ideal gas at 0.80 atm and 87 ˚C, 0.450 liter. How many mol in the sample?(R = 0.0821 liter-atm/ mol ˚K) A. B. C. D.

0.0002 mol 0.0378 mol 0.0122 mol 0.0091 mol

Determine the mass of ice produced from water per day for the following conditions water temperature 20 deg C, tonnage of the unit 150 tons, operating at temperature –5 deg C and 28 deg C, latent heat of ice 330 KJ/kg. A. B. C. D.

107,498 kg 120,465 kg 134,112 kg 140,362 kg

A certain gas at 101.325 kpa and 10 ˚C whose volume is 2.83 cu meter are compressed into a storage vessel of 0.32(0.31kpa) cu meter capacity. Before admission, the storage vessel contain the gas at a pressure and temperature of 137.8 kpa and 26 ˚C, after admission the pressure is increase to 1171.6 kpa. What should be the final temp of the gas in the vessel in kelvin? A. B. C. D.

296.0 319.8 180.0 314.2

A cold storage is required to store 20 tons of fish. The fish is supplied with a temperature of 30 0C . The specific heat of fish below the freezing point is 1.26 KJ/kg-K. The fish is stored in acold storage that is maintained at 8 0C . The freezing point of fish is -4 0C . 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 perfect gas has a value of R = 58.8 ft-lb/ lb. R and k = 1.26. If 20 BTU are added to 10 lb of the gas at constant volume when initial temperature is 90 deg F. Find final temperature. A. B. C. D.

97 ˚F 104 ˚F 154 ˚F 185 ˚F

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

A. B. C. D.

177.11 KW 154.8 KW 168.7 KW 185.3 KW

Ammonia weighing 22 kgs is confirmed inside a cylinder equipped with a piston has an initial pressure of 413 kPa at 38 oC. If 3200 kJ of heat is added to the ammonia until its final pressure and temperature are 413 kPa and 100 oC, respectively. What is the amount of work by the fluid in kJ?

A. 667 B. 304 C. 420 D. 502

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

0.66 0.55 0.77 0.88

A tank contains 90 ft^3 of air at a pressure of 350 Psig; of the air is cooled until its pressure and temperature decreases to 200 Psig and 70 DegF respectively, what is the decrease in internal energy? A. 6232.09 Btu B. -5552 Btu C. 5552 Btu D. -6232.09 Btu

About 3 Hp per ton is required to maintain a temperature of -40 ˚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. B. C. D.

69.72 Kcal/min 70.44 Kcal/min 81.61 Kcal/min 84.65 Kcal/min

A large mining company was provided with a 3 cu. Meter compressed air tank. Air pressure in the tank drops from 700 Kpa to 150 Kpa while the temperature remains constant at 28 ˚C . What percentage has the mass of air in the tank been reduced? A. B. C. D.

74.00 72.45 78.56 78.57

Determine the mass of ice produced from water per day for the following conditions: water temperature 20 deg C, tonnage of the unit 150 tons, operating at temperature -5 deg C and 28 deg C, latent heat of ice 330 kJ/kg.

A. 107,498 kg B. 120,465 kg C. 134,112 kg D. 140,362 kg

A 4 m^3/hr pump delivers water to a pressure tank. At the start, the gage reads 138 Kpa until reads 276 KPa and then pump was shut off. The volume of the tank is 100 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

to emission of body to maintain a comfortable temperature in a dance hall that had an attendance of 1500 people if it has been determined that 75% if the people will be dancing and others will be seated. Tests have shown that an adult will give off 71.8 W of sensible heat while engaging in moderate dancing and 57.1 W of sensible heat while sitting. The 177.3 W for dancers and 45.4 W for sitters.

A. 200 kW B. 267 kW C. 301 kW D. 319 kW

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

a. 50000 lb/hr b. 37500 lb/hr c. 52000 lb/hr d. 45000 lb/hr

A refrigerator is rated at USA one ton capacity. It maintains a cooling temperature of 4.4oC (evaporator temperature). A refrigerant with a refrigerating effect of 136 kJ/kg is in the condenser just ahead of the expansion valve. If the refrigerant vapor has a density of 19.80 kg/m3, what should be the capacity of the compressor?

A. 0.078 m3/min B. 0.091 m3/min C. 0.102 m3/min D. 0.113 m3/min

Determine the air standard efficiency of an engine operating on the ideal cycle with clearance of 6%. When suction pressure is 91.97 Kpa and the fuel is injected 7% of the stroke. Assume k=1.4. A. B. C. D.

62.11% 51.20% 73.58% 60.02%

An engine operating on a Carnot cycle between temperatures 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 B. 160.4 C. 120.5 D. 102.5

kJ/K kJ/K kJ/K kJ/K

Steam at 2Mpa and 250 deg C in a rigid cylinder is cooled until the quality is 30%. Find the heat rejected from the cylinder at 2 Mpa at 250 deg C. V= 0.11144 m3/kg U= 2679.6 KJ/kg Vg=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

A 3 HP refrigerator heat pump operates between 0 deg F and 100 deg F. The maximum theoretical heat that can be transferred from the cold reservoir is nearest to; A. B. C. D.

7600 13000 23000 Btu/hr 35000 Btu/hr

Steam at 1.3MPa, mixture steam and water has an entropy if 3 kJ/kg- oK, Find the enthalpy of the mixture. At 1.3MPa: sf= 2.2515, sg= 6.4952, hf= 814.93, hfg= 1972.7

A. 1627.71 kJ/kg B. 1533.33 kJ/kg C. 1234.45 kJ/kg D. 1162.40 kJ/kg

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 specific gravity of the wood block. A. B. C. D.

0.603 0.504 0.701 0.243

Mixture with 70% quality at 500 Kpa is heated isothermally until the pressure is 300 Kpa. Find the heat added during the process. At 500 Kpa; sf = 1.8607, sg = 4.9606 At 300 Kpa and 151.86 deg C (Psat@500): s = 7.0888 A. B. C. D.

745.92 KJ/kg 535.16 KJ/kg 983.44 KJ/kg 765.34 KJ/kg

A tank contains exactly one kilogram of water consisting of liquid and vapor in equilibrium at 1 Mpa. If the liquid contains one third and the remaining is vapor of the volume of the tank, what is the enthalpy contents of the tank? A. B. C. D.

644.40 KJ/kg 774.40 KJ/kg 785.92 KJ/kg 435.29 KJ/kg

A cylinder 10 ft long and 2 ft in diameter is suspended in air flowing at 8 ft/s. The density of air is 0.00234 slug/ft3 and the coefficient of drag off 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. 0.311 lbf

Water substance at 70 bar and 65 degC enters a boiler tube of constant inside diameter of 25mm. the water leaves the boiler tube at 50 bar and 700degK at velocity of 150m/s/ calculate the inlet velocity(m/sec)

A.1.56 B.2.51 C.1.672 D.3.230

The Reynolds number of a sphere falling in air is 1x106. If the sphere’s radius is 1 ft. What is its velocity? (Pair= 0.00234lbf-sec/ft3) A. B. C. C.

40.6 ft/s 2.5 ft/s 5.1 ft/s 81.2 ft/s

Water substance at 70 bar and 65 deg C enters a boiler tube of constant inside diameter of 35 mm. The water leaves the boiler tube at 50 bar and 700 oK at velocity of 100 m/s. Calculate the inlet volume flow (L/s) A. B. C. D.

0.821 1.261 0.344 1.609

Steam leaves an industrial boiler at 827.4 Kpa and 171.6 deg. C. 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 Deg. C.

A.3.78% B.3.08% C.4.56% D.2.34%

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

Atmospheric pressure at boils 212 deg. F. At the vacuum pressure at 24 in. Hg, the temperature is 142 deg F. Find the boiling temperature when the pressure is increased by 40 psia from atmospheric.

A.449.42 F B.526.34 F C.479.13 F D.263.45 F

A bituminous coal has the following ultimate analysis are 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%

...bulkhead 9.6 m wide and 6 m deep ...two tanks. One tank contains oil of relative ...0.8 to a depth of 4.2 m. Find the total ...bulkhead in MN. A. B. C. 1.168 D. 2.347

A diesel engine consumed 945 liters of fuel per day at 35oC. If the fuel was purchased at 15oC and 30oAPI at P29.00/L. Determine the cost of fuel to operate the engine per day. (di pa alam kung tama to)

A. P5677.50 B. P4677.50 C. P48,088.90 D. 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 27˚API 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 gravimetric analysis C0₂ = 21.6% , 0₂ = 4.2%, N₂ = 74.2%. Specific heat at constant pressure for each component of the exhaust gas in Kcal/kg˚C are CO₂ = 0.203, 0₂ = 0.21 N₂ = 0.248. Calculate the specific gravity of the molecular weight of air is 28.97 kg/kg-mol. A. B. C. D.

0.981 1.244 1.055 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. 2.870 B. 7.526 C. 2.274 D. 6.233

A gaseous fuel mixture has a molar analysis; H ₂ = 14% CH₂ = 3 %, CO = 27%, O₂ = 0.6 CO₂ = 4.5% N₂ = 50 % Determine the air fuel ratio for complete combustion on molar basis. A. B. C. D.

2.130 3.230 1.233 1.130

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 Kpa. Calculate the velocity at this end. A. B. C. D.

4.4 m/s 5.5 m/s 6.6 m/s 3.3 m/s

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 2.0 ft. by what percent should the speed increased for a 290 fthead?

A. 82.5% B. 17.5% C. 72.41% D. 13.5%

Find the work posses for a helium gas at 20C. A. 609kj/kg B. 168kj/kg C. 229kj/kg D. 339kj/kg

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 measured 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. 14.34 m/s

What is the hydraulic gradient of a 1 mile, 17 inches inside diameter pipe when 3300 gal/ml of water flow with f= .03?

A. 0.00714 B. 0.00614 C. 0.00234 D. 0.00187

Convert 750R to K A. 390.33K B. 395K C. 410.33K D. 416.33K

Air compressed adiabatically from 30 to 100oC. If the mass of air being compressed is 5kgm, find the change of entropy

A. 1039 kJ/kg B. 0.746 kJ/kg C. 0 kJ/kg D. 1245 kJ/kg

The sun generates an average of 2 kW/m2 when tapped as a source of energy where in a flat plate collector with an area of 1.5 m2 is used. Flow rate of water inside the collector is 40 liters per hour. Calculate for the temperature rise of the working fluid in oC.

A. 65.14oC B. 60.15oC C. 55.14oC D. 50.15oC

An air standard engine has a compression ratio of 18 and a cut-off ratio of 4. if the intake pressure and temperature are 100 Kpa and 27 ˚C , find the work in KJ/kg. A. B. C. D.

2976 2166 Solved pero 1582 answer sa eval 2751 answer

A throttling calorimeter is connected to the superheated steam line supplying steam to the auxiliary feed pump on a ship. The line pressure measures 2.5 Mpa. The calorimeter 110 Kpa and 150 ˚C. Determine the entropy of the steam. At 110 Kpa and 150˚C hg = 2775 KJ/kg At 2.5 Mpa hf = 962.11 KJ/kg hfg = 1841 KJ/kg sf = 2.5547 sfg = 3.7028 A. B. C. D.

6.8 KJ/kg ˚K 6.2 KJ/kg ˚K 6.6 KJ/kg ˚K 7.5 KJ/kg ˚K

A logging firm in Isabela operates a diesel power plant to supply its electric plant to supply its energy requirement during 24 hrs period, the plant consumed 250 gallons of fuel at 80 deg F and produced 2900 kw-hrs. Industrial fuel ause is 30 deg API and was produced at 3000/L at deg F. Determine the overall thermal eff of the plant. A. B. C. D.

26.08% 34.23% 28.00% 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% e = 30% A stocker fired boiler of 195,000 kg/hr steaming 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

A. 234,019 m3/hr B. 215,830 m3/hr C. 213.830 m3/hr D. 264.830 m3/hr

A windmill with a 6 m radius rotor is to be installed where atmospheric pressure conditions prevail at 101.325 kPa and 21oC. It was observed that wind is blowing steadily at an average velocity of 20 m/s. Assuming that the conversion efficiency 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

23.5 kg of steam per second at 5 Mpa and 400˚C is produced by a steam generator. The feedwater enters the economizer at 145˚C and leaves 205˚C. 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˚C; h = 3195.7 KJ/kg At 5 Mpa; hf = 1154.23, hg = 1640.1 At 205˚C; hf = 875.04 At 145˚C; hf = 610.63

A. B. C. D.

65.22 80.67 88.28 78.82

In a Rankine cycle steam enters the turbine at 2.5MPa (enthalpies and entropies given) and condenser of 50KPa (properties given), what is the thermal efficiency of the cycle? At 2.5MPa: hg = 2803.1 sg = 6.2575 At 50KPa: sf = 1.0910 sfg = 6.5029 hf = 340.49 hfg = 2305.4 vf = 0.0010300

A. 25.55 % 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/s. If thermal efficiency is 36.15%. Find the power needed for the auxiliaries. A. B. C. D.

310 KW 300 KW 400 KW 350 KW

A superheat steam rankine cycle turbine inlet conditions of 17.5 Mpa and 530 ˚C 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 in KJ/kg? A. B. C. D.

17.34 27.32 25.32 47.33

In an open feedwater heater in a steam plant, saturated steam at 7 bar is mixed with subcooled liquid at 7 bar and 25 ˚C. 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 flow rate of subcooled liquid if steam flow rate is 0.85 kg/s. Steam properties are; at 7 bar saturated vapor, hg=2763.5 KJ/kg At 7 bar and 25 ˚C : hf = 105.5 KJ/kg At 7 bar saturated liquid: hf = 697.22 KJ/kg

A. B. C. D.

2.725 kg/s 3.356 kg/s 2.869 kg/s 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 DegC to 24 DegC. Calculate the water flow rate in Kg/s.

A. 583 B. 567 C. 523 D. 528

Steams expands adiabatically in a turbine from 2000 kPa, 400oC to 400 kPa, 250oC. What is the effectiveness of 18oC. Neglect changes in kinetic and potential energy. A. B. C. D.

82 84 79.60 79.46

The annual peak load on a 15,000 kw power plant is 10,500 kw. Two substations are supplied by this plant. Annual energy dispatched through substation A is 27, 500,000 kw-hr with a peak load at 8,900 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 factor of the power plant. A. B. C. D.

1.48, 1.48, 1.75, 1.75,

0.446 0.335 0.335 0.446

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 kg/s and at temperature of 15 ˚C. Calculate the exit temperature of water in ˚C. A. B. C. D.

44.86 42.86 46.45 40.34