Plumbers NZ is New Zealand's largest online plumbing, gas and drainage resource. Plumbing exam help, plumbing news, directory and free quotes.
QUESTION 8
(a) Describe the basic principle on which the operation of a heat pump is based.
(2 marks)
(b) Explain briefly the function of each of the following components of a heat pump having a
reverse cycle.
(i) The evaporator.
(ii) The condenser.
(iii) The compressor.
(iv) The reversing valve.
(v) The capillary tube.
(5 marks)
Total 7 marks
a Absorbtion
b1 Evaporator absorbs heat which changes the state of the liquid refrigerant inside the evaporator, it turns a warm liquid into a cool gas ready for re-compression before it enters the compressor
2 The condenser rejects the heat of compression and also changes the state of a hot gas (from compression) to a wamr liquid
3 The compressor pumps the refrigerant around the circuit
4 The reversing valve reverses the flow of refrigerant through the evaporator and condenser depending on which mode the heat pump is in (cooling or heating)
5 the capilliary tube meters the flow of refrigerant into the evaporator at a fixed rate .The cap line is sized in length to give the correct capacity.