1. The problem statement, all variables and given/known data Air is drawn into a compressor at normal temperature and pressure (N.T.P.) and compressed to a pressure of 6 bar gauge. After compression the air is delivered at 1.2m3 min–1 and cooled to a temperature of 30°C, at which point condensate is collected at the rate of 2 litres per hour. Estimate the FAD (N.T.P.) of the compressor, and the relative humidity of the air entering the compressor. 2. Relevant equations P1 * V1 / T1 = P2 * V2 / T2 3. The attempt at a solution Inlet conditions P1 = 1.013 Bar abs T1 = 15°C = 288.15°K Outlet conditions P2 = 6 Bar + 1.013 bar = 7.013 bar abs V2 = 1.2m3 min-1 T2 = 30°C = 303.15°K P1*V1/T1 = P2*V2/T2 V1 = P2*T1V2 / P1*T2 V1 = 6 * 288.15 * 1.2 / 1.013 * 303.15 V1 = 7.9m3 min-1 FAD (NTP) Can anyone help me with calculating the relative humidity of the air entering the compressor?