Using the suns energy to heat buildings and water are efficient uses of solar power.
Solar space heating systems include south-facing windows and walls or floors that absorb heat during the day and release it at night. Systems can be either active or passive. Active systems use fans or blowers to move the heated air and will often use either air or a liquid to store the heat to use when needed. Passive systems rely on the natural flow of warm air from one space to another. They can include simple direct heat gain, use materials to absorb heat and release it at night, or use spaces isolated from the living quarters such as a greenhouse or sun room. Most people have unexpectedly experienced passive solar heating on a sunny winter day. Solar space heating can reduce heating bills by 50 percent.
Solar water heating includes a collector to heat the water and a tank to store it in. The most widely used systems use a flat plate collector. While they appear similar to the collectors of the 1970s, designs, efficiency and reliability have been vastly improved. Recently, high-efficiency vacuum tubes have been developed. A system covering only 36 square feet can provide 100 percent of an average familys hot water during the summer and 70 percent over the course of an entire year. According to the Wisconsin Solar Energy Lab, a typical familys electric water heater releases as much CO2 as their car.
A system can also be designed to produce both warm air and hot water.
Backward to the Future, Home Patron and Solar Service, all solar hot water installers, will have displays at the Renewable Energy and Sustainable Living Fair. Workshops will also discuss both flat plate and evacuated tube collectors.
The Fair is sponsored by the Illinois Clean Energy Community Foundation, the Illinois Department of Commerce and Economic Opportunity, Commonwealth Edison and The Rock River Times.
From the July 20-26, 2005, issue