Question

1. Comment on the following (Be brief) with the help of schematic diagram, if required :
   1. In the reciprocating compressors used in vapour compression system, the mass of refrigerant discharged by the compressor reduces as the pressure ratio is increased.
   2. Thermostatic expansion valve is preferred over automatic expansion valve as throtting device.
   3. COP of refrigeration system increases when water cooled condenser is used in place of air cooled condenser.
   4. Vapour at suction to the hermetically sealed compressor is always superheated vapour.

                    For low sensible heat factor applications, re-heat is necessary.