Space heating and cooling use 46% of all energy consumed in U.S. buildings. Air-conditioning is the single leading cause of peak demand for electricity and is a major user of chlorofluorocarbons (CFCs). Advanced energy conversion technology can save 50% of this energy and eliminate CFCs completely. Besides saving energy, advanced systems substantially reduce emissions of carbon dioxide (a greenhouse gas), sulfur dioxide, and nitrogen oxides, which contribute to smog and acid rain. These emissions result from the burning of fossil fuels used to generate electricity.
Researchers at the BTC are involved in R&D that will lead to the commercialization of a new generation of advanced absorption cycle heat pumps and chillers for residential and commercial space conditioning. The thermally activated heat pump (TAHP) can revolutionize the way residential and commercial buildings are heated and cooled. It enables highly efficient heat pump cycles to replace the best natural gas furnaces, reducing energy use by as much as 50%, while also providing gas-fired air conditioning. In large commercial-size absorption chillers, energy efficiency can be improved by 50% with advanced high-temperature cycles and novel fluids.
Two technologies are being targeted:
Heat pumps in use today are electrically driven, operating on the conventional vapor-compression refrigeration cycle, taking heat at a lower temperature and releasing it at a higher temperature. A reversing valve allows the heat pump to provide space heating or cooling as necessary.
A major advantage of the heat pump over conventional furnaces is that it can deliver more than one unit of output energy per unit of input energy. In other words, its coefficient of performance (COP) is greater than 1. The COP for the best combustion heating processes is only about 0.95 because of thermodynamic losses. In addition, the heat pump can be driven directly by thermal energy from natural gas. This avoids the substantial energy conversion losses (approximately 70%) associated with electric power generation and distribution.