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) Approximately 100m tube length can be taken along the loss of 5mH2O, pump head (mH2O): Transmission System,Lubrication Oil Pump,Cooling Oil Pump,Start And Stop Oil Pump Fuxin Dare Automotive Parts Co., Ltd. (DARE AUTO) , https://www.darepump.com
Pump head simple estimation method
Hmax = ΔP1 + ΔP2 + 0.05L (1 + K)
â–³ P1 water chiller evaporator water pressure drop.
â–³ P2 is the water pressure drop of the one unit with the largest hydraulic loss in each of the air-conditioner front-end units connected in parallel in the ring.
L is the tube length of the most adverse loop
K is the ratio of the total resistance equivalent length of the most unfavorable loop to the total length of the straight pipe. When the most unfavorable loop is long, the value of K is 0.2 to 0.3 and the value of K is 0.4 to 0.6 when the most adverse loop is short.