Performance test and fault diagnosis for chillers based on chilled water flow rate variation

Studies the influence of chilled water flow rate variation on the performance of chillers under the constant flow rate/variable temperature difference and variable flow rate/constant temperature difference conditions. The results show that a larger chilled water flow rate variation range in evaporator will not affect the stability of the system for large chillers; cooling capacity of chiller is linear with chilled water flow rate in a certain scope and the coefficient of performance (COP) of chiller is basically constant, which provides guidance for energy saving operation of the chilled water pumps; allowable diversification range of chilled water flow velocity  can increase on conditions of comparative large water flow rate in evaporator coils; the ultimate chilled water flow rate variation should be less than 10.1% of the design flow rate per minute, otherwise it will lead to unsafe operation of the chiller; and the chiller performance fluctuations caused by deviant chilled water flow rate variation can provide some foundations for fault detection and diagnosis (FDD).