The choice of HVAC pump: Centrifugal type water pump with the specific speed ns of 130-150 is usually selected. The flow rate of the pump should be 1.1-1.2 times of the rated flow rate of the chiller (1.1 for single unit and 1.2 for parallel unit) The approximate loss of 5mH2O along the length of each 100m tube length is mH2O: Hmax = ΔP1 + ΔP2 + 0.05L (1 + K) ΔP1 is the water pressure drop of the chiller evaporator. ΔP2 is L is the tube length of the most adverse loop, K is the sum of the local resistance equivalent length in the most adverse loop, The ratio of the total length, when the most unfavorable loop longer K value of 0.2 to 0.3, the most adverse loop shorter when the value of K 0.4 to 0.6