Another way to use renewable energy in your home is to use solar energy for water heating. Today's systems carry a rating that tells you how well they'll meet your hot water needs. And they provide a clean, reliable, and cost-effective source of hot water.
Solar water heaters can be either active or passive. An active system uses an electric pump to circulate the heat transfer fluid; a passive system has no pump.
Most systems use a roof-mounted solar collector, so you'll need a south-facing roof with good solar exposure. A typical solar water heating system circulates water or an antifreeze solution through this solar collector, where the sun's heat warms the liquid.
If water is used, the system circulates the water between the solar collector and a storage tank in your house, and the storage tank serves as your source of hot water. If an antifreeze solution is used, the system will also circulate it between the solar collector and a storage tank, but water is circulated through coils in the tank to provide your hot water. In some cases, an additional tank is then used to store the hot water.
If you're currently using an electric water heater, solar water heating is a cost-effective alternative. In fact, a study by the Florida Solar Energy Center
showed solar water-heater owners saved as much as 50% to 85% annually on their utility bills as compared to electric water heating. If you're building a new home, the cost of the system can be spread over the term of your mortgage. The only pollution generated by solar water heating is the pollution produced in generating electricity to power the pumps and controls. Some systems even operate without pumps, reducing the environmental effects to a negligible amount and helps reduce greenhouse gases. When a solar water heater replaces an electric water heater, the electricity displaced over 20 years represents more than 50 tons of avoided carbon dioxide (a greenhouse gas) emissions alone.
Take the same care in choosing a solar water heater that you would in purchasing any major appliance. Your best protection is to consider only certified and labeled systems. The Solar Rating and Certification Corporation (SRCC), a nonprofit, independent third-party organization formed by the solar industry, state energy officials, and consumer advocates certifies and rates solar water heaters.
As with all renewable energy systems, you should check to see if any special rebates or financing deals are provided in your state. Rebates are often offered through your local electric utility. Consult with your state energy office, or see the resources listed at the end of this chapter for other information sources.
Hot water b—>- to house v*— Cold water supply
Solar storage/ backup water heater
Double-walled heat exchanger
Active, Closed-Loop Solar Water Heater
Renewable Energy at Home: A Look Toward the Future oday, most new home buyers get to choose their carpets, countertops, flooring, and other decorative options. Soon, the choices might include adding a solar water heater, a geothermal heat pump, or heat-storing Trombe walls. Builders are beginning to offer green homes that save energy and water while increasing comfort. Climate-responsive architecture along with whole-house design principles will drastically reduce home energy use. And lower utility bills mean homeowners will have more money to spend turning that house into a home.
Renewables for Heating and Lighting RESOURCES
American Council for an Energy Efficient Economy (ACEEE)
ACEEE is a nonprofit organization dedicated to advancing energy efficiency as a means of promoting both economic prosperity and environmental protection. ACEEE provides publications and guides on making your home more energy efficient.
Alliance to Save Energy
The alliance to Save Energy is a nonprofit coalition of business, government, environmental, and consumer leaders who promote the efficient and clean use of energy. Contact the alliance for information and publications on energy efficiency.
Renewables for Heating and Lighting RESOURCES
Efficient Windows Collaborative
http://www.efficientwindows.org/ Access helpful guidelines on window selection from this site.
http://www.energystar.gov This site provides information on how to select Energy Star® windows, boilers, furnaces, heat pumps, and other Energy Star® appliances and products.
Financing Solutions Web Site: Homeowners
The homeowners section of this Web site provides links to several resources on renewable energy financing.
The Geo-Heat Center provides technical/economic analysis for those actively involved in geothermal development. Technical material on resources, direct use equipment, design schemes, and software are also available.
Geothermal Heat Pump Consortium (GHPC)
http://www.ghpc.org/ 1-888-ALL-4-GEO (255-4436) The Geothermal Heat Pump Consortium provides extensive information on the use of geothermal heat pumps.
Home Energy Saver
This site, hosted by the Lawrence Berkeley National Laboratory, is designed to help consumers identify the best ways to save energy in their homes and access many "how to" resources. You can use an online calculator to compute your home's energy use and plug in energy efficiency improvements to see how much savings you can realize.
RESFEN Windows Software
This software package from the U.S. Department of Energy helps you evaluate windows. To obtain a copy of RESFEN, fax your request, with your mailing address, to Software Request at: 510-486-4089. Or mail your request to: Software Request Windows & Daylighting Group MS 90-3111
Lawrence Berkeley National Laboratory Berkeley, CA 94720
Solar Benefits Model
This Web site allows you to calculate the benefits of including a solar water heating system in your new home.
Solar Rating and Certification Corporation (SRCC) http://www.solar-rating.org/about.htm 407-638-1537
SRCC publishes the thermal-performance ratings of solar energy equipment. They also offer a directory of certified solar systems and collectors as well as a document (0G-300-91) that details the operating guidelines and minimum standards for certifying solar hot-water systems.
The Sustainable Buildings Industry
The SBIC Web site provides design software and other resources for saving energy in buildings and effectively using solar energy.
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