A Carnot heat pump cycle operating with ammonia as the working fluid rejects energy by heat transfer to a thermal reservoir at 120°F. During the isothermal heat rejection, the ammonia starts as a saturated vapour and ends as a saturated liquid. The cycle receives energy by heat transfer from a reservoir at 10°F.
a) Determine the heat transfer and work per unit mass of ammonia, in Btu/lbm, for each process in the cycle.
b) Determine the coefficient of performance of the cycle.