A double-acting single cylinder reciprocating air compressor has a piston displacement of 0.015 m3 per revolution, operates at 500 r.p.m. and has a 5% clearance. The air is received at 1 bar and delivered at 6 bar. The compression and expansion are polytropic with n = 1.3. Determine
(i) the volumetric efficiency
(ii) the power required, and
(iii) the heat transferred and its direction, during compression if inlet temperature of air is 20°C.