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Consider that refrigerators account for 12% of U.S. residential
energy use, and water heaters for another 17%. But today's consumers
can choose appliances that are vastly more energy- and resource-efficient
than earlier generations of products, thanks in part to technologies
developed by the Department of Energy and its partners. One innovation
alone—an improved refrigerator-freezer compressor—saved
consumers more than $6 billion in energy costs between 1980 and
1990.
With continued R&D, DOE seeks to build on this record of success,
developing and demonstrating technologies that will enable manufacturers
to further improve the energy efficiency of appliances, while maintaining
or enhancing their performance and value. The potential energy savings
are significant.
Strategy and Program Goals
DOE supports research and development on highly energy-efficient
refrigerators, clothes washers and dryers, water heaters, and other
appliances. The program also accelerates the introduction and widespread
use of highly efficient appliances through voluntary partnerships
with industry.
DOE is also investigating strategies for appliance integration, as part of efforts to enable net-zero-energy buildings. In a Habitat for Humanities test house,
Oak Ridge National Laboratory is recovering waste heat from the
refrigerator to improve the efficiency of the heat pump water heater.
Appliance integration and enhanced appliance controls will be key
focus areas for future R&D.
Research Area Highlights
Recent R&D success stories address a number of major home appliances:
Advanced refrigerator-freezer—In a cooperative agreement with the AHAM Appliance Research Consortium to establish technically achievable energy saving, DOE researchers
designed and demonstrated an advanced refrigerator-freezer that
uses less than 1 kilowatt-hour per day—half as much energy
as the latest government standards allow, and one-fifth as much
as 1972 models. This outstanding energy efficiency was achieved
by:
- Using vacuum insulation panels around the freezer section and
a double-insulation thickness of polyurethane foam on the doors.
- Replacing standard AC fan motors with more efficient DC motors.
- Replacing the automatic defrost control with an adaptive defrost
that operates only when needed.
Power consumption for a 20-square-foot refrigerator-freezer is
only 0.93 kilowatt-hours per day, a performance level far exceeding
the government's 2001 energy standard, which requires units of this
size to consume no more than 2.01 kilowatt-hours per day. If all
125 million refrigerator-freezers in the United States operated
as efficiently, consumers would save $6.5 billion annually.
Horizontal-axis clothes washers—A landmark study, conducted
by Oak Ridge National Laboratory, demonstrated the benefits of horizontal-axis
clothes washers. In cooperation with Maytag, the study tested the
real-world efficiency of the washers in the small community of Bern,
Kansas. The study found energy savings of 60% and water savings
of 40%. A follow-up demonstration in Boston, Massachusetts produced
equally impressive results.
"Drop-in" residential heat pump water heater—Heat pump
water heaters (HPWH) can attain much higher efficiencies than conventional
electric water heaters. Yet the residential market for HPWHs has
remained small because of long payback times, low perceived reliability,
and the need for specialized installation and service. DOE, in a
cooperative effort with private industry and the Oak Ridge National
Laboratory, developed and tested a HPWH that overcomes these drawbacks,
opening the way to greater market acceptance. A "drop-in" replacement
for 50- or 80-gallon electric water heaters, the new HPWH has the
same footprint as the original water heater and an identical electrical
hookup, and Laboratory testing verified the durability and lifetime
expectancy of components. The HPWH not only saves annual energy
but also contributes to peak load shaving, and, as a side benefit,
provides cool, dehumidified air to help condition the surrounding
space in summer, spring, and fall. Advanced HPWHs under development
promise significantly lower first costs. DOE's goal is to reduce
the first cost of an advanced HPWH by 65%, compared to today's HPWH
costs.
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