Evaluation of Regenerator Performances in Stirling Heat Pumps

KUBOTA has been developing a gas engine-driven Stirling heat pump using both engine shaft power and engine exhaust heat. Since Stirling heat pumps work at small temperature difference, comparing with Stirling engines, COP is much influenced by the regenerator performances such as flow loss and heat transfer. The performances of three kinds of wire mesh regenerators made of stainless steel were investigated by numerical simulations. From the experimental results, the wire mesh of which wire diameter was 45 μ m showed the best regenerator performances in our operating conditions. And the results of the numerical simulations were well fitted for the experimental results. Finally, from the loss relations, the best regenerator specifications in Stirling heat pumps could be found.