in tandem and a single lshx 110 each compressor has suction port 125 and discharge port 135 suction ports 125 are connected to a suction manifold or unitary pipe 127 leading from lshx 110 discharge ports 135 are connected into a discharge manifold 136 now representing a part of a vapor refrigerant interface obviously more than two compressors can be connected in tandem within integral module 177 also as described below in fig5 individual components of integral module 177 and compressors 151 and 152 in particular are preferably positioned on a common base turning now to fig5 illustrated is an integral module 187 preferably positioned on a common base 194 and consisting of two sub modules 185 and 186 each sub module has its own combination of a compressor and lshx in particular sub module 185 includes compressor 191 and lshx 181 and sub module 186 comprises compressor 193 and lshx 183 in other words within module 187 each compressor is connected to its own lshx it has to be noted that vapor and liquid refrigerant interfaces each consist of four pairs of connections in particular a liquid refrigerant interface comprises a pair of connections 130 to a condenser outlet or outlets and a pair of connections 131 to an expansion device inlet or inlets further a vapor refrigerant interface comprises a pair of connections 115 to an evaporator outlet or outlets and a pair of discharge ports 135 associated with compressors 191 and 193 each compressor lshx.