DESIGN AND CONSTRUCTION OF A SOLAR WATER HEATER FOR DOMESTIC USE. A RESEARCH PROJECT MATERIAL ON MECHANICAL ENGINEERING
Flat plate collectors for solar water heat were population in Florida and southern California in the 1920s. Photo type Israeli solar water heater, the first commercial company to manufacture solar water heater due to abundance of sunlight is it used by 20% of the population by year 1967.
1.2 SOLAR ENERGY
Solar energy is the light which come in form of electromagnetic radiation. Electromagnetic radition is a wave like phenomenon that move energy across distance.
Solar energy is the most abundant continuing source of energy available to the human race. Solar energy is not being used as primary sources of fuel energy but a large research and development effort has being underway to develop economical systems to harness solar energy as a major source of energy particularly for the heating and cooling of buildings.
Solar has the following advantage
i) It is very attractive
ii) It is non polluting
iii) It is non deflectable (not quickly use)
iv) It is reliable and free.
On the other hand, solar energy has this disadvantage
Solar energy can be converted directly into other form of energy in their separate conversion process, they are:
1) THE HELIOTHERMAL PROCESS : This is absorption of solar radiation and conversion of the energy into thermal energy is the only solar conversion that has a theoretical conversion efficiency of 100%
2) THE HELIOCHEMICAL PROCESS: This is the photosynthetic reaction. The reaction is the sources all biomass and fossil fuel.
3) THE HELIOELECTRICAL PROCESS: This is the production of electricity by photovoltaic or solar cells.
It is estimated that the rate at which solar energy arrives at the earth is about 1.72 x 10MW. The amount of solar energy incident on a horizontal surface range from 3.5 to 7kwh/m2/day. About 30% of the total amount is reflected to space, 47% is converted to low temperature heat and reradiated to space and 23% powers the evaporation/ precipitation cycle of the biosphere. Less than 1/2 % is represented in the kinetic energy of the wind and waves and in photosynthetic storage in plant.
1.3 USE OF SOLAR ENERGY
Over the years solar energy has been put to several uses ranging from drying of cloth and agricultural product to sun tanning the body and of course for food preservation. Other areas of solar energy use is air conditioning for cooling and heating of a building for human comfort using absorption cooling system.