a low pressure high temperature gas liquid mixture 14 enters the compressor 12 and is compressed to a higher pressure in the figures liquid streams are represented by a solid line gas streams are represented by a dashed line and gas liquid mixtures are represented by combined solid and dashed lines because the liquid and gas are in intimate thermal contact during compression and the thermal capacitance of liquids is typically significantly greater than that of the gas within the mixture 14 the system 10 is operated so that the heat of compression of the gas within the mixture 14 is absorbed by the liquid within the mixture 14 preferably to the extent that the gas is compressed nearly isothermally this relationship can be quantified as the capacitance rate ratio c ratio defined as where m l and c l are respectively the mass flow rate and thermal capacitance of the liquid the product of m l and c l is the thermal capacitance rate of the liquid m g and c p g are respectively the mass flow rate and thermal capacitance of the gas and the product of m g and c p g is the thermal capacitance rate of the gas from the above equation it is evident that the c ratio of the system 10 will depend on the particular gas and liquid used and their relative.