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.