Thermomolecular energy convertors—II. Heat pumps and zero-work refrigerators

A thermomolecular heat pump is analysed wherein the cooling effect is the result of the effusion of gas molecules through a capillary material due to an externally applied pressure difference. Large temperature differences, heat transfer through the capillary material and a potential energy barrier are included in the expressions developed for gas flow rate and cooling effect. The maximum efficiency is evaluated as a function of operating temperature ratio along with the minimum obtainable refrigerated temperature for several values of appropriate parameters. A zero-work refrigeration device, having no moving parts, obtained by directly coupling two thermomolecular devices operating over three temperature levels, is treated with expressions developed for mass flow rate and heat rates. Minimum obtainable refrigerated temperature and effectiveness are evaluated.