Performance comparison investigation on different pulse tube position heat pumps with power recovery displacer.

Spacecraft waste heat is dissipated into space primarily by radiation. To improve the heat dissipation efficiency of spacecraft radiators in high-temperature environments and reduce heat wastage in spaceflight thermal control systems, thermoacoustic heat pumps (TAHP) are considered a viable method for increasing radiator cooling temperatures and recovering waste heat. In this study, one-dimensional simulations are used to optimize the geometrical parameters of the 100-watt work recovery thermoacoustic heat pump (WRTAHP) for various pulse tube positions. The performances of the two systems are compared at a cold-end temperature of 293 K and a hotend temperature of 353 K. The results reveal that a heating capacity of 256 W with a relative Carnot efficiency of 35.01 % is achieved for the pulse tube front-type thermoacoustic heat pump (FTTAHP),  hereas the pulse tube back-type thermoacoustic heat pump (BTTAHP) obtains a heating capacity of 225 W with a relative Carnot efficiency of 30.59 %. As the cold-end temperature decreases, the coefficient of performance is reduced for FTTAHP, while the performance of BTTAHP shows a substantial improvement. At a cold end temperature of 233 K and a hot-cold end temperature difference of 60 K, a heating capacity of 268 W with a relative Carnot efficiency of 50.57 % is achieved for BTTAHP. Furthermore, the heating capacity of the BTTAHP is not significantly increased by adopting the active phase adjustment structure. In summary, the FTTAHP is suitable for spacecraft radiator applications and avoids high temperatures affecting compressor operation, whereas the BTTAHP is better suited for low-temperature heating.