Refrigerant-134a at 1.5 MPa, 90oC is to be cooled by air to a state of 1 MPa

Question:

Refrigerant-134a at 1.5 MPa, 90oC is to be cooled by air to a state of 1 MPa and 27oC in a steady-flow heat exchanger. The air enters at 110 kPa and 25oC with a volume flow rate of 820 m3/min and leaves at 95 kPa and 62oC. Neglecting any heat losses, determine
(a) The mass flow rate of refrigerant.
(b) The entropy generation rate in the system's universe.