The term thermal solar power refers to systems that convert solar radiation into useful heat. This is also referred to as passive solar energy. It is a different type of system from solar power electricity, and whose usefulness should not be overlooked.
The uses for thermal solar power are widespread and varied. Just think of any process which could utilize heat. This could range from something simple such as hot water heating, to more sophisticated designs involve stirling engines or industrial grade steam.
For small scale applications, thermal solar power is used in the home. The heat is used to maintain hot water tanks, or is stored in the floors or walls of our buildings.
There are other good uses for thermal solar power which we expect to increase in years to come. One is pebble bed heat exchangers, which act as a thermal storage bank for converted heat. This gives us some system capacity and operating flexibility.
These pebble bed heat exchangers can be designed into your floors, walls, workshops, or other places around the home. They can be used for household heating, greenhouses, saunas, and as air driers for clothes. We had one design whereby a user wanted to heat up a nesting area in their chicken coupe!
The typical operating temperature for most thermal solar power systems will be between 100F and 180F. In good solar climates these temperatures can be easily achieved with popular off the shelf equipment. With more specialized equipment we can go in excess of 250F, and with high performance industrial equipment over 700 degrees is possible. These high performance systems are usually for making steam, but incorporating them into other processes is also possible.
At the core of any thermal solar power system will be the solar collector. This is the component directly responsible for generating your heat. The most common design is the flat plate absorber, which often have selective surfaces for high absorptivity and low emissivity of solar radiation. Other designs include evacuated tube collectors, and parabolic trough concentrating receivers.
The lifeblood of the thermal solar power design is the circulating fluid. The circulating fluid is heated in the solar collector, and then pumped to all the system users. This fluid is typically oil, glycol, or water which is matched to the system temperatures and equipment in use.
Anyone interested in energy independence and self-sustainability should thoroughly investigate thermal solar energy. Most systems are fairly simple and rank very well in affordability. If you live in a climate with a good reputation for Sun, then there is a pretty good chance you could be using a thermal solar power system of some form.
Thermal power systems are typically less expensive than solar power electricity, and can create household hot water and heat reliably. With the addition of pebble bed storage and higher operating temperatures, then the amount of potential uses suddenly becomes many. With the markets of sustainability re-growing their roots we expect to see a variety of new designs and installations in years to come.
Originally posted 2009-07-18 04:52:19.