The wash still in a whisky distillery uses mechanical vapour re-compression as shown in the simplified diagram of the Figure shown below. The vapour from the still is at 80° C. Take a minimum temperature difference between the vapour leaving the still and the steam in the heat exchanger of about 20 K, and a minimum temperature difference between the steam in the coil and the liquid in the still also of about 20 K. Assuming a compressor isentropic efficiency of 0.65, and a combined mechanical and electrical transmission efficiency for the compressor motor of 0.9, choose suitable pressures for the steam circuit and calculate the COP of the heat pump.