Assessment of economical and ecological benefits from deployment of a domestic combined heat and power unit based on its experimental performance

A number of technologies have been embarked upon for combating the problems of escalating energy requirements and the resulting greenhouse gas emissions. Micro or domestic combined heat and power (CHP) has been considered to be one of such technologies. Estimation of the benefits from implementing a pre-commercial prototype of a WhisperGen Mk 3, Stirling engine based, micro CHP (MCHP) unit, in a typical UK semi-detached house with high efficiency electrical appliances and with a typical non-condensing boiler was carried out and some of these results are presented in this article. The initial stage of the investigations focused on mapping thermal and electrical operational performance of the MCHP through physical experimentation on the pre-production unit. Then, to estimate the economical and environmental benefits over a 12-month period, the typical heat and power demand profiles within a household were modelled. In the final stage of the research, the operation of MCHP was simulated within the household, taking into account information on heat and electricity demands and data on the experimental performance of the domestic CHP system. The simulation indicated that with the application of this pre-commercial prototype as a replacement for the typical non-condensing boiler a 9 per cent reduction in both utility bills (using electricity and natural gas prices that were effective in March 2005) and CO2 emissions with a seasonal efficiency of 86 per cent could be achieved assuming that no auxiliary heating system was used to rapidly compensate the hot water deficit in the storage tank in periods of the high hot water demand.