Answer Happy

You are asked to design a heat pump which operates on a simple vapour compression cycle. The working fluid, Ammonia (NH), leaves the evaporator dry. saturated and enters the compressor where it is compressed reversibly and adiabatically. Condensation at constant pressure then takes place until the saturated liquid state is reached. This is followed by adiabatic throttling to evaporator pressure. Constant pressure evaporation completes the cycle. Heat pump information: The heat pump requires 15 seconds to warm the air of a room with a volume V from 2 °C to 20 °C. This process can be considered a constant pressure process. The condensor pressure is 8.570 bar. The work input rate into the compressor is 13 KW. The quality factor of the liquid vapour mixture entering the evaporator is 0.1454. Note that to complete the questions you will have to choose a volume V in the range 45 m to 55 m a) Sketch the cycle on T-s and p-h diagrams. [3 marks) b) 1) By choosing a room volume V in the range 45 m to 55 m and stating all assumptions and chosen parameters, determine the heat transfer rate from the condenser. [4 marks] i) Determine the evaporator pressure. [3 marks) ) Set up two equations to be able to determine the mass flow rate through the heat pump and the enthalpy entering the condensor. [2 marks] IV) By initially guessing the amount of superheat in the condensor, solve the equations in ) iteratively or otherwise, determine the mass flow rate and the enthalpy entering the condenser. Working and methodology must be shown for full marks. TURN OVER MECHODOS 2021-22 [5 marks) ) Determine the coefficient of performance for the cycle. [2 marks] Vi) Determine the coefficient of performance of a heat pump operating on the reversed Camot cycle between thermal sink temperatures corresponding to the saturation pressures in the above cycle. Comment on your result [3 marks) vii) Discuss this cycle in the context of the second law of thermodynamics [3 marks)