Natural gas is enjoying a resurgence in popularity these days for several good reasons. It's a clean-burning fuel. When burned, it gives off 40% less carbon dioxide than coal used to provide electrical power. And it's abundant and affordable.
To make natural gas even more affordable, ORNL has been funding the development of a highly efficient gas-fired heat pump for providing air conditioning and heating. Working with commercial partners, Bob DeVault, Patricia Garland, Abdi Zaltash, Phil Fairchild, and others in ORNL's Energy Division have guided the development of the generator-absorber heat exchanger (GAX) technology, a heat pump that is designed to use 30 to 50% less energy than other systems.
Village Green home with GAX heat pump during ribbon-cutting ceremony in 1999.
In mid-1999, the first pre-production GAX
absorption air conditioners were installed in model homes in the new
Village Green subdivision in Southern California. The test began following
a ribbon cutting on May 13, 1999, at Village Green, that was attended
by ORNL's DeVault, Ron Fiskum (DOE program sponsor), and Dan Reicher
(DOE Assistant Secretary for Energy Efficiency and Renewable Energy).
The 183-unit Village Green subdivision is being constructed in phases
over a projected two-year period. By the end of 1999, more than 50 homes,
all with GAX absorption air conditioners, were under construction. For
comparison, several comparable homes using conventional heating and
cooling units will also be monitored to obtain baseline data. Although
it is too early to have seasonal test results from Village Green, the
new GAX absorption air conditioners have received the standard independent
product certifications required of all residential air-conditioning
systems. The GAX air conditioners were independently certified as being
29% more efficient than the single-effect absorption air conditioners
that have been produced for decades.
Robur Corporation of Evansville, Indiana, the manufacturer of the old single-effect Servel air conditioners, has introduced both 3-ton and 5-ton residential and light-commercial GAX absorption air conditioners into the marketplace. Robur plans to convert its absorption air conditioner production entirely to the new GAX technology during 2000.
In a separate, parallel industry cost-shared
effort, ORNL and its commercial partner, the Unitary Gas Heating and Cooling Products Consortium (a gas industry limited liability company created by a consortium of gas utilities and pipeline companies), continue to develop prototype GAX absorption air conditioners and heat pumps. Support for the ORNL-DOE program comes from Southern California Gas Company (the largest gas utility in the United States), Southwest Gas Corporation (the fastest-growing gas utility because Las Vegas and Phoenix are in its service territory), Mississippi Valley Gas Company, Texas Gas Transmission, and others.
ORNL researchers in the Buildings Technology
Center are also supporting the development and field testing of a novel
type of electric heat pump for heating water that produces hot water
twice as efficiently as conventional units. "Water heating accounts
for about 17% of the energy consumed in a typical household, so
it's a good candidate for energy savings," says ORNL's John Tomlinson.
"But conventional electric water heaters are reaching their efficiency
limits. We need to apply heat pump technology instead of resistance
heaters to water heating."
Tomlinson, Randy Linkous, and others in the Energy Division are providing technical support to Enviromaster International, a small company located in upstate New York, for the development and field testing of a heat pump water heater designed for the large electric water heater replacement market. The researchers will also aid in promoting the technology through DOE's Energy Star Program.
An electric heat pump water heater (HPWH) uses about half as much electricity as conventional water-heating units. Nevertheless, HPWHs have not sold well because the technology is unfamiliar, the cost of each unit is high, and early models were unreliable and difficult to install. The new electric HPWH is designed to be more attractive to consumers.
Unlike earlier HPWH models, the new drop-in model can easily be installed by a plumber to replace the existing water heater. The installed cost of the new HPWH will be about $400 more than that of a conventional 50-gallon water heater, but for many families, the energy savings in two years will cover this additional cost.
A prototype of the heat pump water heater. Image enhanced by Rosemary Adams.
Round-the-clock durability testing of the
HPWH design was scheduled to begin at ORNL in the spring of 2000. These
accelerated tests will continue for nine months, subjecting the HPWH
to the equivalent of 10 years of real-world use. In addition, a field
study of the HPWH will begin this summer at 18 test sites located across
the country. These tests are being conducted in partnership with a number
of large and small utilities. Commercial launch for the new design is
anticipated in early 2001.
Once these new heating and cooling devices
are commercialized, it is hoped that many consumers will get pumped
up about the energy savings these technologies will bring.