Experimental study of a free piston Stirling cooler with wound wire mesh regenerator

Abstract Free piston Stirling coolers have the advantages of high energy efficiency, environmental friendliness, wide cooling temperature range and easily-controlled cooling capacity, which is very attractive for deep-freezing applications. From the perspective of enhancing its competitiveness, here reports the use of wound wire mesh instead of the conventional stacked wire mesh to fill the regenerator, which brings low material waste, simplified manufacturing process and low flow resistance. In order to optimize the performance, a method of squeezing the bulges with variable heights into the mesh to adjust the porosity is used. A numerical model of cooler is first established to assist the system design, then experiments are done and compared with the simulation results. In the experiments, a coefficient of performance using wound wire mesh regenerator with a porosity of 72.7% is 0.8 at 102 W@-38 °C and 0.25 at 45 W@-80 °C, respectively. Though the comparison with stacked wire mesh regenerator shows that it leads to a relatively worse performance, the cooling performance is still comparable to that of vapor-compression refrigerators in the deep-freezing temperature region. Through further optimization, the application of wound wire mesh is promising.