Prepared in association with Heat Transfer Laboratory, Dept. of Mechanical Engineering, Massachusetts Institute of TechnologyThe heat pump has long been of interest as a heating device because
of its ability to deliver more heat energy than it consumes. The present
work outlines past, present, and future developments in heat pump technology
and indicates key areas of improvement. One method of improvement, the capacity controlled heat pump, has been studied in detail.
An analysis of conventional and capacity controlled air-to-air heat
pumps has been performed, using detailed computer simulations. New system
sizing guidelines are outlined for capacity controlled units, resulting in
as much as a 30% per year energy savings over conventional heat pumps in
two of the six locations studied.
Economic studies, comparing conventional and capacity controlled heat
pumps to gas and electrical resistance heat, with and without air conditioning, indicate that capacity controlled heat pumps could soon be superior
to gas heating in some locations, depending on energy prices. All of the
economic studies have been done for a range of gas and electricity prices,
and include amortization of capital costs as well as operating costs.
Finally, preliminary development work on a new, potentially efficient
and inexpensive, continuously variable compressor capacity control device
is described. Test results on components of the early suction-valve cut-off
control mechanism indicate that it is possible to design a controllable
device to function in high speed (3600 RPM) compressors. However, more
development work is needed
