Geothermal Resource Descriptions

Part 4 of Geothermal Energy Under Our Feet. Hydrothermal A hydrothermal system is defined as a subterranean geothermal reservoir that transfers heat energy upward by vertical circulation of fluids driven by differences in fluid density that correspond to differences in temperature (see Figure 2). Hydrothermal systems can be classified into two types—vapor-dominated and hot water— […]

Successful 2006 Small Wind Projects

Part 6 of Wind Power for the 21st Century. Southwest Windpower conducted performance optimization and blade-fatigue tests at the NWTC on its new Skystream wind turbine. The 1.8-kW turbine, developed in partnership with DOE, won the Best of What’s New Award from Popular Science Magazine and was listed as a best invention for 2006 by […]

How to size a Photovoltaic System to Meet Your Needs

After you have assessed the appropriateness of your site, you need to determine how much electricity your PV system must generate. This depends on how much electricity your loads require. Again, your dealer can help you with sizing a system that will meet your needs. The sidebar illustrates the steps involved in sizing a PV […]

What Is a Geothermal Heat Pump & How does it work?

Part 2 of Geothermal Heat Pumps. Geothermal heat pumps can reduce energy consumption—and corresponding air pollution emissions—up to 44% compared to air source heat pumps and up to 72% compared to electric resistance heating with standard air-conditioning equipment. (Source: EPA, 1993) Geothermal heat pumps are viable nationwide. They use the Earth as a heat sink […]

Resources: Air-Source Heat Pumps

Part 8 of Air-Source Heat Pumps. The following are sources of additional information on heat pumps. This list is not exhaustive, nor does the mention of any resource constitute a recommendation or endorsement. Ask an Energy Expert DOE’s Energy Efficiency and Renewable Energy Clearinghouse (EREC) P.O. Box 3048 Merrifield, VA 22116 1-800-DOE-EREC (363-3732) Online submittal form. Energy […]

Maintaining and Servicing

Part 7 of Air-Source Heat Pumps. Heat-pump performance will deteriorate without regular maintenance and service. The difference between the energy consumption of a well-maintained heat pump and a severely neglected one ranges from 10 to 25 percent. Regular Maintenance Either the homeowner or service technician can perform the following routine maintenance tasks: Clean or replace […]

Increasing Water-Heating System Efficiency

Part 3 of Energy-Efficient Water Heating. Reducing hot-water usage is primarily a matter of common sense and exerting a little extra effort to not be wasteful. Once you have applied a few simple, low-cost measures for reducing hot-water consumption, you may want to consider water-heating system improvements if you wish to further reduce your energy […]

Reducing the Amount of Hot Water Used

Part 2 of Energy-Efficient Water Heating. Generally, four destination points in the home are recognized as end uses for hot water: faucets, showers, dishwashers, and washing machines. Now, you do not have to take cold showers, dine on dirty dishes, or wear dirty clothes to reduce your hot water consumption. Less radical measures are available […]

The Battery Bank & Sizes and Costs

Part 2 of Battery Power for Your Residential Solar Electric System. The basic building block of a lead-acid battery is a 2-volt cell. A battery bank is a collection of connected 2-, 6-, or 12-volt batteries that supply power to the household in case of outages or low production from renewable energy sources. The batteries […]

Zero Energy Community, Vista Monta

Part 1 of Zero Energy Community. Vista Montaña In August 2003, Clarum Homes opened the doors at Vista Montaña, California’s largest Zero Energy Home community, with homes designed to use almost zero net electricity over the course of a year. Built on a former apple orchard, all homes in the development will harvest the sun to […]

Resources: Elements of an Energy-Efficient House

Part 8 of Elements of an Energy-Efficient House. The following are sources of additional information on energy-efficient houses: The Energy Efficiency and Renewable Energy Clearinghouse (EREC) P.O. Box 3048 Merrifield, VA22116 1-800-DOE-EREC (1-800-363-3732) EREC provides free general and technical information to the public on many topics and technologies pertaining to energy efficiency and renewable energy. […]

Demand Water Heaters

Part 3 of Selecting a New Water Heater. It is possible to completely eliminate standby heat losses from the tank and reduce energy consumption 20% to 30% with demand (or instantaneous) water heaters, which do not have storage tanks. Cold water travels through a pipe into the unit, and either a gas burner or an […]