Conventional and modular design of domestic heat pumps.

This thesis is concerned with an experimental and theoretical investigation of domestic heat pumps. The development of heat pumps in the 1970's did not meet the original expectations and this thesis examines the reasons why. The items considered included cycling and unsteady conditions created whilst matching the heat pump's output to meet a space heating load. A detailed study was made of the hermetically sealed refrigerant compressor, the heat exchangers, and the refrigerant pressure and temperature control systems. In addition to the conventional heat pump a study was made of the advantages gained from modular designed heat pumps.The application of heat pumps to U.K. dwellings and climatic conditions was studied together with the suitability of thermostatic control. Initial studies were made of the operation of a demonstration unit. This showed how intermittent operation would reduce a heat pump performance and was followed by the development of a computer model which simulated the complete refrigerant circulation system. This allowed a study to be made of a heat pump performance at part load conditions. A computer model of the complete refrigerant cycle was developed which aided in the design and construction of a heat pump which used refrigerant R12. This was followed by the construction of a second test rig using R 134(a). The completed R 134(a) test rig was installed in an environmental chamber which could simulate outdoor weather conditions. Results from the test rigs indicated that the performance was greatly affected by on/off cycling an item that was further investigated.