Energy saving characteristics of gas engine home cogeneration systems

The energy saving potential of micro-scale gas engine cogeneration systems installed in detached residential houses was studied experimentally and theoretically. First, the energy demands for electricity and hot water were measured experimentally, with a 1-minute sampling time interval, in two houses for one year. Based on these measured data, a simulation model was built to analyse and compare the energy saving characteristics of the cogeneration systems with a corresponding conventional system. The estimated results show that the total primary energy consumption of the cogeneration system in the two houses was 4.5% and 10.1% higher than that of conventional system. Therefore it did not contribute to energy saving in these houses. Next, the maximum potential energy saving characteristics of the cogeneration system was investigated by constructing a mathematical model which optimises the system's operation to minimise total primary energy consumption. It became clear that under theoretically optimal conditions the above total primary energy consumption ratios could be decreased by up to 5.5% and 6.6% in the two houses.