Study of IPLV (Part 2): Application discussion

Points out that the definitions of  A, B, C, D in the calculation and examination formula for IPLV in the current standard GB 50189—2005 are the coefficients of performance (COP) for the four points of 100%, 75%, 50% and 25% of the load, but not the corresponding sectors of the whole load range divided by taking 100%, 75%, 50% and 25% of load as the indices. The specific conditions for the load points of the four sectors required by the standard will be ignored when using the formula to calculate the cooling load and the annual energy consumption under the annual operating mode, leading to deficiency of strictness in theory. The standard adopts two indices, COP for the nominal operating mode and IPLV, at one time when evaluating the performance of a water chiller, of which either is indispensable.