Charlottesville Online | Real-estate / Solar Energy browse

by Roger Voisinet, EcoBroker

Every homeowner should know something about solar and other technologies which save energy in homes and commercial buildings. Americans are finally getting the message that 5% of the world's population simply can't keep consuming 25% of the globe's fossil fuels. This lifestyle is contributing to political instabilities and global warming. According to recent polls, 80% of respondents felt that home builders should offer solar technologies as an option for all new homes. Whether or not builders offer this as an option, a good realtor should be able to direct his or her clients towards reputable suppliers of solar water and pool heaters and photo-voltaic systems.

Solar water heaters are the most cost effective use of the sun's free energy. Because electric and gas water heaters are used by families throughout the entire year (unlike heating systems), a typical solar water heater can return it's initial investment to the home owner in 5-7 years on the average. A solar water heater works in conjunction with the existing gas or electric tanks and consists of the following:

two or more solar panels normally mounted on a south facing roof. The panels are either 4' x 8' or 4' x 12'. A typical panel would have a metal frame housing a copper absorber plate sandwiched between insulation and tempered glass. Water or anti freeze would circulate through the absorber plate picking up heat from the sun during daylight hours.
an 80 or 120 gallon storage tank located adjacent to the back-up electric or gas tank.
a heat exchanger, pump and differential controller assembly located on or adjacent to the solar tank.
insulated, copper piping connecting the panels to the heat exchanger.
a heat transfer fluid, usually propylene glycol in freezing areas or water where freezing is not a concern.

The differential controller senses the temperature at the solar panels (hottest point of the system) and the bottom of the solar tank (coldest point of the system) and turns on the circulator when there is a positive difference (when the sun is heating the panels). In this way, heat is transferred to the solar tank when it is available and it saved for later use when needed.

For periods of little or no sun, the back-up fuel supplies any additional hot water needs. A properly sized solar system should supply 60-75% of a families' annual hot water needs. These systems cost about $5800-6800 installed. However, this year the Federal Government has reinstated the popular solar tax credit from the 1980's. 30% of the cost of the system is paid for by the Federal Government via a tax credit (not tax deduction) bringing the next cost to about $4200. Hundreds of systems my company (Virginia Solar Contracting Services) installed in the 1980's paid for themselves before the end of the 80's and supplied free hot water for the owners for decades with little maintenance.

Another use for solar is to heat a swimming pool. Here the goal is to extend the pool heating season a few months on either end and the solar panels are only asked to heat the water to 82 degrees or so. Solar pool panels are usually made of plastic and circulate the pool water directly through the solar absorber plate. No tax credits are available for solar pool heaters.

You have probably heard a lot about solar photo-voltaics and have seen them by the highway or on a boat. Photo-voltaic panels use a different technology to make electricity.These systems are considerably more expensive and have not experienced wide spread adoptance by home owners yet. However the interest is very high and with an installation technique called net metering, the total system cost can be reduced. Net metering is where a home owner produces electricity directly from sunlight but instead of storing the energy in costly batteries for later use, he or she sends the solar-generated electricity directly into the grid via the meter. This way you either use what you produce or you "sell" the kilowatts to the system provider and receive a credit (usually by having your meter run backwards). This eliminates batteries and the space they require but one would still have to be connected to the grid.

Solar Energy

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