Solar energy in its various forms can qualify both as a better source and a better use of energy in many applications. Individual, on-site collection systems (like oil water heater) can supply heat at temperatures adequate for space
and water heating with simple. direct conversion of light to heat — without using greater temperatures than we need for the job.
Electricity can be produced by the direct conversion of the mechanical energy in wind through windmills or (in the future) through quantum conversion, as in photovoltaic cells. High temperatures can be supplied by focusing collectors and by fuels supplied from growing plants. However, if we attempt to supply all of our energy needs by constructing large, high
temperature electrical generation facilities powered by the sun, we could run into many of the problems associated with our present fossil fuel technology.
The solar water heating system described in this manual is a concrete project that can supply energy to help reduce your water heating bill
By building and installing the water heater yourself, you will save one-half to two-thirds the cost of a high quality commercially available system, and still receive three-quarters of the energy that the best systems can give you. You will also gain an understanding of solar energy and of how your system works– plus the skills and experience acquired in building and installing it that you can get no other way.The Solar Water Heater Workshop Manual