Stirling Engine: An Emerging Prime Mover for Micro-CHP Systems

In this paper, an analysis of different micro-CHP systems is made from the point of view of benefits and limitations of several prime movers used in micro-CHP systems: reciprocating engines, Stirling engines, micro steam and gas turbines and fuel cell systems. A comparison using the metrics and weighting factors is suggesting that the reciprocating engines and the Stirling engines are more appropriate for the micro-CHP. In another analysis, micro-CHP factors related to efficiency and thermal/electric power for different prime movers are compared. Micro-CHP systems with Stirling engine has the best score. The electric efficiency is better for micro-CHP systems with reciprocating engines, and Stirling engines are in the second place. The thermal efficiency is better for micro-CHP systems with Stirling engines followed by reciprocating engines. Stirling engines use an external heat source, which simplifies design, minimizes noise and vibration, and allow multi-fuel use. These features make the Stirling engine a promising alternative to the internal combustion engine.