the purge side 26 of the filter 10 most of the filtered air is directed to a mixer 30 in the cabin 22 where the partially cooled dry clean air is mixed with compartment air the mixed air is drawn from the mixer 30 by a recirculation blower 32 then further cooled in an evaporator 34 which absorbs for example in an exemplary system discussed hereinafter 27 000 btu hr heat load on a continuous basis the cooled air is then discharged into the cabin 22 while a portion of the air leaks from the cabin 22 to ambient the bulk of the air is returned to the mixer 30 the air that leaks from the cabin 22 is replaced by clean air from the subatmospheric pressure swing filter 10 the vapor cycle portion of the system 8 used to cool the two evaporators 14 and 34 uses freon r113 as the working fluid the vapor cycle system 8 comprises a compressor 40 connected in the conventional manner to a condenser 42 receiver 48 thence to the evaporators 14 and 34 for return to the compressor 40 ambient air is ducted from a condenser blower 44 to the condenser 42 thence is returned to ambient the two evaporators 14 and 34 can be separately controlled for temperature and capacity by a set of orifices 50 51 and 52 the overall power requirement for the system can be computed and sized up or down with system components retaining the same.