Aug 7 2010
Despite a year of temperature extremes, the Tennessee Valley Authority has seen significant energy savings at its research project for energy efficient homes.
July marked the first full year of data collection at TVA's energy efficient homes project at Campbell Creek subdivision in Knox County.
"Power bills for the most energy efficient of the three houses totaled less than $450 for the entire year," Project Manager David Dinse said. "That averages out to about $37 per month for a three-bedroom, two-and-a-half-bath house."
"With solar panels, super-efficient materials, better insulation and other technologies, TVA's advanced efficiency house is not your typical home. But this has not been a typical year."
TVA's power production peak for the past year came during a colder-than-normal January, while this June was one of the hottest ever in Tennessee, according to TVA records.
"During our first full year of data collection we recorded remarkable energy savings even in hot and cold temperatures beyond the normal extremes for the TVA service region," Dinse said. "In fact, it was in these most extreme conditions that our advanced technology home realized the greatest cost savings."
The research project is measuring energy consumption in three, two-story homes of similar size (2,400 to 2,500 square feet) on similar lots with similar solar and wind exposure. Inside, automated mechanisms replicate the occupancy of a family of four, regularly opening and closing the refrigerator, using the oven, running the clothes dryer or taking a shower.
The difference is that one home is an advanced house with energy efficient features, including solar electricity and hot water, installed during construction. A second house was retrofitted with aftermarket efficiency upgrades, including a heat-pump water heater. The third house is a standard, code-certified home that serves as a control.
The first year data showed that in hotter periods such as this June, the advanced house uses only about half the energy of the retrofit house and less than a third compared to the standard house.
"In recent hot weather, the power meter on the advanced house has actually spun backward," Dinse said. "On what would ordinarily have been hot, energy intensive days, the solar generation was actually creating a credit toward the power bill."
"The retrofit house demonstrates that good insulation, efficient appliances and routing air ducts through conditioned space produce very good results for a moderate investment. The advanced house features cost about $30,000 extra during construction and the retrofit upgrades were added for about $10,000."
Rudy Shankar, vice president for Technology Innovation in TVA's Environment and Technology organization, said a full year of seasonal changes and weather extremes will help TVA better understand the houses' capabilities and to integrate more of the energy-saving technologies into standard homes.
"The first year of analysis under controlled conditions will provide a basis for introducing more energy efficient appliances, better insulation techniques and advanced construction materials, and help document further savings in the future," Shankar said. "One of the goals of this project is to establish a pipeline of energy efficiency products with verifiable savings for implementation across the TVA service territory."
Partners in the TVA project include Oak Ridge National Laboratory and the Electric Power Research Institute.
Source: http://www.tva.com/