The Norwich Heat Pump

Abstract

The paper provides the history and constructional details and working results of what is believed to be the first large heat pump used for building heating in Great Britain. This machine was constructed and installed as an experimental machine for heating a large block of municipal buildings in Norwich. A brief explanation indicating the principle upon which the heat pump works is given. Reference is also made to the differences between the reversed heat engine when working as a refrigerator and when working as a heat pump. In the latter case there is a deliberate increase in the final temperature T1, from approximately 85 deg. F. to temperatures which may be of the order of 150–200 deg. F. The unsuitability of the term “coefficient of performance”—normally used as a criterion of refrigerator performance—when used as a coefficient relating to the heat pump is pointed out; and the use of a new, alternative term is suggested. The results are shown of operating the Norwich Heat Pump for two winter heating seasons. When using an unsuitable compressor the heat delivered to the building was found to be 3·45 times greater than the equivalent heat (electric) energy required to operate the machine, averaged over the 1945–6 winter heating season. With a more efficient compressor, installed later in 1946, a still better performance is anticipated. The actual costs of heating the building, with coal-fired boilers and a heat pump respectively, are shown in the form of a table. Conclusions indicated are that the heat pump can show a financial saving, as compared with the use of coal-fired boilers, and that it is practicable to use the heat pump in Great Britain for building heating throughout normal English winters.