In a single pass heat exchanger of an air conditioning system, warm air flows over a pipe carrying refrigerant R134a. The air, with a mass flow rate of 56.2 kg/min and at 100 kPa, needs to be cooled down from 37 °C to 27 °C. The refrigerant enters the tubes at 500 kPa with a quality of 20% and exits at 500 kPa, 20 °C. If there is no heat transfer between the heat exchanger and the surroundings, determine the amount of the refrigerant necessary to cool down the air, in kg/min.