- HG suction gas-cooled - HA air-cooled Suction gas-cooled semi-hermetic compressor HG and air-cooled compressor HA. Full capacity range of innovative, modern compressor technology with 2/4/6 and 8-cylinders. Suitable for all current refrigerants, as well as CO2. For the EX range we are the first European manufacturer to offer compressors certified according to ATEX machine category 2.