INTRODUCTION:
The energy generated by the SUN, WATER, & WIND is abundant. These energy sources are called as renewable energy sources. The energy from these sources is not used widely as the conventional sources are used (for petrol & gases). So these energy sources are called as “ NON-CONVENTIONAL ENERGY SOURCES”. The energy from these sources is available at, one time cost, rather than recurring costs. Sun delivers three types of energies such as light, heat & rays.
Now, utilization of these energies is the basic need of the modern days to get freedom from power cut, loadshading & shutdowns of conventional energy sources. The main purpose of using non-conventional energy sources is to make the Nature, pollution free.
Solar water heating system : Any black coloured, non-shining, non-transparent & rough surface absorbs more heat. Solar water heating system works on the basis of ‘BLACK BODY RADIATION and ABSORPTION’
Flat plate collector- absorber plate:-
Absorber plate absorbs the solar power & transmits the solar power into heat. The transmitted heat is absorbed by water in tubes connected to absorber plate. The quantity of preheated water from solar system depends on the solar radiation, temperature of atmosphere, temperature of circulating water, & quality of insulation.
A collector of an approximate size 1m x 2 m, i.e. 2 Sq.m area can give 100 to 125 liters of preheated water of about 600 to 800c temperature.
Absorber plates are painted with specified black colour & special coating, which withstands against temperature variations. This helps in utilizing the solar power to the maximum limit.
Collector glazing / glass cover: –
A thick transparent toughened glass is used over absorber to restrict the transmission of the heat outside the box, generated by absorbers. The other purpose of fixing glass cover on the absorber plate is to safeguard the plates also.
Collector insulation: –
The purpose of collector insulation is to restrict the transmission losses of the generated heat from the sides, except the collector glazing.
Casing collector box:-
The purpose of casing collector box is to protect insulation & absorber plate, against atmosphere & heat losses.
Tubes :-
These insulation tubes are provided to circulate the cold & heated water to & from the collector.
The preheated water storage tank is made from such a material, which has good resistivety against the atmospheric changes & which will not affect the quality of water stored inside the tank. The type of insulation, for the water tank, depends on the desired temperature of heated water, lowest temperature of atmosphere & quality of insulation. Insulation is covered by a thin aluminum sheet to protect it from rains & atmosphere.
Pipelines are required to carry the heated water up to the user. These pipelines are insulated with glass wool & aluminium sheet. (Mica 50 mm thick insulation) to avoid heat losses. Double insulated P.V.C. pipes (special Kytech) can be used.
Process of heating: –
When sunrays fall on the collector glazing, the energy from the sun rays is absorbed by the collector and is transmitted in the form of heat.
This transmitted heat is absorbed by the water in rising tubes.
Thus water is heated due to absorption and It becomes light in weight & goes in the storage tank. Water is continuously circulated on the basis of thermosyphon in tubes.
One cycle of circulation of water through tubes up to tank, gives a minimum rise of 50c. Temperature. The temperature of water can be achieved upto 250c to 650c.
Maintenance:-
If solar systems are made from first quality material, it can last long upto 20 to 25 years. Weekly cleaning of collector glazing is necessary for efficient working of the system. Thus the total system requires very less maintenance
