Solar thermal system

Introduction to solar thermal system
Working of solar thermal system
Solar collector
Type of solar collector
Solar water heater
Solar heating and cooling
Solar refrigeration and air conditioning
Advantage and Disadvantages

1. Solar thermal system The instistute of science Course code;-mphsec2t Sunil dhanare Milind punjara DHIRAJKUMAR GUPTA Sunita shah

2. TOPICS Introduction to solar thermal system Working of solar thermal system Solar collector Type of solar collector Solar water heater Solar heating and cooling Solar refrigeration and air conditioning Solar- cookers,dryers,distillation Advantage and Disadvantages

3. Introduction: Sun is the most abundant,reliable and renewable source of energy. This energy can be harnessed by two way: 1).Solar thermal 2).Solar photovoltaic Solar thermal energy is the advance techniques which produces maximum efficient enrgy compare to photovoltaic cell.

4. Year Description 1866 Auguste Mouchout used a parabolic trough to produce steam for the first solar steam engine 1886 First patent for a solar collector was obtained by the Italian Alessandro Battaglia in Genoa, Italy 1913 Frank Shuman finished a 55 HP parabolic solar thermal energy station in Maadi , Egypt for irrigation 1929 First solar-power system using a mirror dish was built by American Scientist Dr. R.H. Goddard. 1968 First concentrated-solar plant, which entered into operation in Sant'Ilario , near Genoa, Italy 1984 Parabolic-trough technology of the Solar Energy Generating Systems (SEGS) begun its combined capacity354 MW. 2014 World's largest solar thermal plant (392 MW) achieves commercial operation in Ivanpah Califoma , USA History

5. Solar thermal system: Solar thermal power (electricity) generation systems collect and concentrate sunlight to produce the high temperature heat needed to generate electricity. Solar thermal collectors can absorb nearly the entire solar spectrum. Thus concentrated solar power (CSP) technology is more efficient than photovoltaic solar cells.

6. Solar collector: Solar power has low density per unit area (1 kW/sq. m. to 0.1 kW/sq. m.) hence it is to be collected by covering large ground area. Solar thermal collector essentially forms the first unit in a solar thermal system. It absorbs solar energy as heat and then transfers it to heat transport fluid efficiently. The heat transport fluid delivers this heat to thermal storage tank / boiler / heat exchanger, etc., to be utilized in the subsequent stages of the system.

7. Concentrating solar technologies Low temperature (<100 C) Medium temperature-line focusing(<400 C) High temperature –point focusing(>400 C) flat plate collector solar chimney solar pond Parabolic trough collector(PTC) Fresnel collector Central tower collector Parabolic dish collector Classification of solar collector on basis of their concentrating temperature

8. 1.Low temperature collectors (<100 "C): Flat plate solar collector Flat plate collector is basically a black surface that is placed at a convenient path of a sun The sun heats a dark flat surface, and then the energy is transferred to water, air, or other fluid for further use• These are used in domestic house hold purpose like water heating & space heating etc.They operate in the temperature range from 30 to 80 "C.

9. 2. Medium temperature collectors – Line focusing (<400 °C): Parabolic trough collector (PTC): Parabolic trough is the linear-focus collector. It consists of a cylindrically curved parabolic mirror, which reflects the sunlight onto a tubular receiver positioned in the focus line of the parabola.. The tubular receiver contains the fluid that absorbs heat and transfers it via circulation to the boiler or another device to produce steam. PTCS are made by simple bending a sheet of reflective or highly polished material into a parabolic shape.

10. 3. High temperature collectors – Point focusing (>400 "C): Central tower collector: In this system multiple tracking mirrors (heliostats) positioned in the field around central receiver installed on a tower These systems are capable of reaching of much higher levels of concentration than linear systems Typically 80 to 95% of the reflected energy is absorbed into the working fluid which is pumped up into the receiver The working fluid is used as heat source to produce steam and convert it to electricity• The generated thermal energy can be stored in amolten salt storage

11. Solar water heater A Solar Water Heater is a device which provides hot water for bathing, washing, cleaning, etc. using solar energy. It is generally installed at the terrace or where suntight is availableA tilted flat plate solar collector with water as heat transfer fluid is used.

12. Working of solar water heater A thermally insulated hot water storage tank is mounted above the collector. The heated water of the collector rises up to the hot water tank and replaces an equal quantity of cold water, which enters the collector. The cycle repeats, resulting in all the water of the hot water tank getting heated up. When hot water is taken out from hot water outlet, the same is replaced by cold water from cold-water make up tank fixed above the hot water tank. The scheme is known as passive heating scheme, When the collector is fixed above the level of hot water tank, a pump is required to induce circulation of water in the loop and the scheme will be known as active (or forced) solar thermal system

13. Solar heating and cooling technology: solar heating Solar heating and cooling technology receive the thermal energy from sun and utilize this energy to provide hot water, space heating and pool heating for residential, commercial and industrial applications. These applications of SHCS reduce the dependency on electricity or natural fuels. The main function of solar system is to convert sun light into heat. The primary requirement of SHCS is to setup the light collectors with higher efficiency

14. Active and passive Solar heating: Active solar heating: This system can be used as commercial hot water as well as space heat. A space heat application involves some additional connecting hardware for space heat distribution system. Active solar heating system involve following major components:Collectors to absorb energy,Circulation system,Storage tank,Backup heating system, Control system Passive solar heating: Passive solar heating is the least costly technique to heat home space. The main aim of this system is to kept out heat in summer and kept in heat in winter from sun light. Passive solar heating also depends on ventilation or windows provided in buildings or houses.

15. Solar cooling Solar cooling is a technology that converts sun light heat energy into useful cooling of buildings. The process works by using solar heat collecting and supplied this heat to the thermal cooling system, to generate chilled water.

16. Solar air conditioning and refrigeration: Solar refrigeration The principle of absorption refrigeration was first demonstrated by Faraday in 1825. Thus, this is one of the oldest cycles for producing refrigeration effect, which differs fundamentally from the conventional vapour compression cycle in the method for compressing the refrigerant. Refrigerator which run on electricity provided by solar energy is known as solar refrigeration

17. Working of solar refrigerator In absorption cycle cooling systems two working fluids: a refrigerant and an absorbent-refrigerant solution are used. The absorbent-refrigeration combination is so chosen that the absorbent have high affinity for the refrigerant and at the same temperature, vapour pressure of the refrigerant is higher than that of absorbent. The absorbent cooling is based on the principle that the refrigerant can be bound by a liquid or solid solvent, known as absorbent to release heat during absorption, while it absorbs heat during evaporation (and thus producing cooling effect). Though large number of refrigerant-absorbent combination is possible, the two most common and commercially tried combinations are: LiBr -water ( LiBr as absorbent and water as 176 Non-Conventional Energy Resources refrigerant) and aqua-ammonia (water as absorbent and ammonia as refrigerant). In the former the absorbent is a solid (a salt) whereas in the later it is a liquid. The performance of a cooling cycle is judged from its COP (coefficient of performance), which is defined as the ratio of amount of cooling produced to the energy input.

18. Solar air conditioning and refrigeration: Solar air conditioning: Air-conditioning is one of the majorconsumers of electrical energy. The demand can be expected to increase because of changing working times, increased comfort expectations and global warming. Solar air-conditioning might be a way to reduce the demand for electricity. Process of converting solar thermal energy (heat) into conditioned

19. Conventional vs solar air conditioning Conventional air conditioning When a liquid gas changes its state, it takes or extract heat. At lower pressure, state changes at lower temp. Extraction of heat means cooling. Gas gets compressed when heated. Gaseous refrigerant compressed and then heated up in the solar panel up to 90°C. solar air conditioning In this system, water is used as the refrigerant while lithium bromide (Li Br)/ammonia is used as the absorbent In the absorber, the lithium bromide absorbs the water refrigerant, creating a solution of water and lithium bromide Lithium bromide has great affinity for water vapour , however, when the water. lithium bromide solution is formed, they are not completely soluble with each other

20. Advantage and D isdvantages advantages There will be no fuel cost as the power plant runs by sun energy It doesn't cause pollution and global warming effects It uses existing equipment like solar thermal mirrors, turbines etc . Can store energy using molten salts instead of using batteries Uses less space than photovoltaics for same energy generation output Running costs of solar thermal are cheaper than coal or gas plants disadvantages The initial capital costs for solar thermal is large Uses lot of water which is major problem in desert areas Usage of massive arrays of mirrors impacts the wildlife species These plants can be installed only in places which have high amount of solar radiation Solar thermal can't be installed in residential area Build time would be longer than other forms of energy generation

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