Solar Water Heater

A Presentation on “Solar Water Heater”

By Santosh Thapa 072MSREE517

Objectives: Main Objective: To know about solar water heater

Specific Objective: To know about different types of solar water heater , existing technologies, financial, SWOT analysis ,environmental effect etc.

Introduction • Solar water heaters were developed some two hundred years ago. The first known flat plate collector was made by H.B. de Sausurre, a Swiss. • Used for heating the water, for producing the steam for domestic and industrial purposes by utilizing the solar energy. • heapest and most easily affordable clean energy . • Expose a dark surface to solar radiation so that the radiation is absorbed. A part of the absorbed radiation is then transferred to a fluid like air or water. • Consists 3 parts which are Heat collection system, heat storage system and auxiliary heating system

Working principle of solar water heater • A solar water heater is an array of solar collector to collect solar energy and an insulated tank to store hot water. • Both are connected to each other. • During the day time, water in solar collectors get heated which is either pumped or flown automatically on thermo-siphon principle to the storage tank. • Hot water then stored in the tank can be used for various applications.

Types: Passive system: – There are no pumps used in the operation. – The collector is close to the area where heat is stored or required. – Natural process such as conduction, convection and radiation are used to transfer heat . – cheaper than active systems. – example is a thermo-siphon solar water heater system

Active system: • The energy is used or stored in a location away from the surface being heated by the sun. • Pump or fans are used to transport the fluid heated by the collector to the storage unit and sometimes from the storage unit to the load. • A common example is solar pool heating system.

Existing technology Existing technology of solar water heater are a) Flat-plate collector based SWH technology. b) Evacuated tube collector(ETC) based SWH technology. c) Integral collector-storage SWH technology.

a) Flat-plate collector based technology:

Fig: Front view of FPC

Fig: Side view of FPC

• The solar radiation is absorbed by flat plate collectors which consist of an insulated outer metallic box covered on the top with glass sheet. • Inside there are black metallic absorber(selectively coated) sheets with built in channel or riser tubes to carry water. • The absorber absorbs the solar radiation and transfer the heat to the flowing water. • The flat-plate collector is the important type of solar collector because it is simple in design, has no moving parts and requires little maintenance. It can be used for a variety of applications in which temperatures ranging from 40°C to about 100°C are required.

b) Evacuated tube collector based technology:

• Evacuated tube collector is made of double layer borosilicate glass tubes evacuated for providing insulation. • Each tube contains a glass outer tube and metal absorber tube attached to a fin. The fin’s coating absorbs solar energy but inhibits radiative heat loss • Evacuated-tube collectors generally have a smaller solar collecting surface because this surface must be encased by an evacuated glass tube.

c) Integral collector-storage system

• Other solar water heating systems the collector and storage tank are separate components. • In an integral collector storage (ICS) system, both collection and solar storage are combined within a single unit. • The entire unit is exposed to solar energy throughout the day. • The resulting water is drawn off either directly to the service location or as replacement hot water to an auxiliary storage tank as water is drawn for use.

Installation setup

• Strength

SWOT Analysis

• • • • • •

source of energy is never ending totally pollution free can be utilized for different purpose like bathing , cooking, drying , washing etc . easy to operate minimum working expenditure saves fossil fuel and electricity cost • A 100 liters capacity solar water heater saves 1500 units of electricity annually. • A solar water heater of 100 liters capacity can prevent emission of 1.5 tons of CO2 per year. • Weakness

• • • • • •

back-up is needed in cloudy day initial investment is high not yet taken on priority list Not much tracking or monitoring of systems at present suitable storage tank is needed for using on no sunshine hours. the legal, technical and economical conditions are not yet completely defined.

• Opportunity •vast opportunity for expansion in many use. • pollution free • unstable access to fossil fuel • adequate technology for local market • increasing price of energy

• Threats • threat from oil lobby • threat from coal lobby • low demand • fluctuation due to weather may discourage consumers • insufficient government support

Financial analysis • Financial analysis is required while taking purchase decisions of solar water heater

• Factors used for financial analysis are interest rate, inflation rate, unit cost of electricity/fuel rate, operation and maintenance cost and solar water heater service life.

• Payback periods 1) when electricity is replaced: payback period = 2 to 4 years 2) when coal is replaced: payback period = 5 to 6 years

Comparison of cost between FTC and ETC type SWH FPC 125 LPD Rs)

(IC

ETC 130 LPD (IC Rs)

Initial cost

25000

20165

Installation cost

3000

3000

One time maintenance cost

1000

1000

Operational expenditure/year

0

0

Related Organizations • National – Alternative Energy Promotion Centre (AEPC) – Centre for Renewable Technology (CRT) – Other private companies like Lotus Energy, Gham Power, Sipradi Energy, etc.

• International – International Renewable Energy Agency (IREA), etc.

Role on Energy Conservation and Climate change issues

• Renewable Energy Source • No Carbon Emission • A SWH of 100 liters capacity can prevent emission pf 1.5 tones of CO2 per year • Decrease the use of fuels to generate electricity or direct use. • Reduce Green house gases

Conclusions • Renewable Energy with no harmful emissions • Free and abundant source of energy • High starting cost and unaffordable by medium class people

References • www.aepc.gov.np • http://www.heliodyne.com/industry_professiona ls/downloads/Evacuated%20Tube%20Comp.pdf • http://www.undp.org/content/dam/india/docs/use r%E2%80%99s_handbook_on_solar_water_heaters.pd f • http://www.waaree.com/downloadPDFs/Faqs_FAQ_So lar_Water_Heater.pdf • http://libgen.io/scimag/get.php?doi=10.1016/S0 196-8904(00)00153-9&open=1

Thank You