Capacity of the refrigeration plant in tones of refrigeration

Question

An ammonia ice plant operates on simple saturation cycle at the following temperatures:

        Condensing temperature = 40 ⁰C

        Evaporation temperature = –15 ⁰C

        It produces 10 tonnes of ice per day at –5⁰C from water at 30⁰C. If the COP of the system is 5, determine :               20

1. Capacity of the refrigeration plant in tones of refrigeration
2. Mass flow rate of the refrigerant, kg/min
3. Isentropic discharge enthalpy, kJ/kg

Take :

C_p = 4.187 kJ/kg-K for water = 2.000 kJ/kg-K for ice

Latent heat of fussion of ice = 335 kJ/kg

Sensible enthalpy at 40 ⁰C = 6000 kJ/kg

Enthalpy of sat. vapour at –15 ⁰C = 1675 kJ/kg