It is necessary to provide a suitable working envifoment for crew members working witnm the limited space inside a combat vemcle，not only for the pro?vision of a comfortable working condition, but first of all for an enhaocement of combat effectiveness of the crew-members. Conventional air conditioners often cannot fulfill these functions and requirements. The paper presents three feasible schemes of the positive displacement refrigeration type for air con?ditioning armoured vehicles. Besides their scJiemes, flow charts for computa?tion and the results of thermal-calculations of the heat cycles are given, A com-parison with similar schems that of the turbo-type air refrigeration of the British Aerospace Dynamics Group and that of the conventional vapor-com?pression refrigeration are then given, regardina their technical and economi-calaspects.