Reciprocating Joule-cycle engine for domestic CHP systems

The reciprocating Joule-cycle engine operates on a recuperated gas-turbine cycle and is intended to provide high thermal efficiency in small sizes (1–10 kW). It is designed to achieve a higher efficiency than a comparable gas-turbine by using a reciprocating compressor and expander to provide very high compression and expansion efficiencies. Possible power plants for small combined heat-and-power systems currently include Stirling engines, internal-combustion engines, gas-turbines and fuel cells. The reciprocating Joule-cycle engine appears to have considerable advantages compared with other prime movers in terms of efficiency, emissions and multi-fuel capability. The present study estimates the performance of such an engine and is the first stage in a larger project that will in due course produce a demonstration engine.