Solar energy is a term that refers to the direct use of sunlight to produce heat or electric power.  The sun’s energy is plentiful, but it is thinly distributed over a large area. It must be collected and concentrated in order to produce usable power. The amount of solar radiation per unit of flat area is above 1,000 Watts per square meter.

Heat used in a solar thermal system is guided by five basic principles: heat gain; heat transfer; heat storage; heat transport; and heat insulation. Here, heat is the measure of the amount of thermal energy an object contains and is the product of temperature and mass. The higher the temperature of a substance, the more heat it absorbed. Of course, some materials require more heat to become warmer than others — this is caused by differences in so called specific heat of substances. (more…)