stage 12 and illustrating the air cooled condenser version in some process tool installations water as a cooling medium must be avoided thus the air cooled condenser with a fan 32 mounted on a transverse rotational axis as seen in fig3 and 5 provides air flow across conventional internal refrigerant flow conduits not seen in fig4 5 and 6 toward an outlet screen extending across the module width this fan 32 is also deployed to direct air centrifugally outward and laterally toward the lower stage module 12 through air slots in the housing well inasmuch as the internal configuration of the upper stage module 10 can be in accordance with the teaching of k w cowans patent application ser no 10 079 542 referred to above these details are not described herein however the slots in the sidewall of the upper module 10 that faces the lower stage module 12 provide a flow cooling air transversely between the two modules 10 12 and over the finned conduits 34 for the suva 95 lines from the lower stage compressor 62 that can be seen adjacent these orifices fig4 5 and 6 also demonstrate that there are only two direct refrigerant couplings between the sidewall of the upper stage module 10 and the facing side of the lower stage module 12 furthermore the modules 10 12 are.