Question

A piston-cylinder assembly contains 2.5 kg of saturated refrigerant R-134a with a quality of 10 % at 0 °C (State 1). There is a linear spring mounted on the piston such that when the mixture is heated the pressure reaches 1000 kPa with a volume of 70 L just as the piston touches the stop (State 2). The system is then heated further until a pressure of 1200 kPa is reached (State 3). a) Find the volume of the refrigerant in State 1. b) Calculate the work done by the device during the process from State 1 to State 3. c) Calculate the heat transfer required for this process. Also clearly indicate the direction of the heat transfer (whether into or out of the piston-cylinder system).