Development of a simplified chiller plant calculation tool: architecture, method and verification

Abstract

In view of the cumbersome parameter settings, inaccurate results under partial load conditions, and shortcomings when focusing too much on the chiller performance of existing chiller plant calculation tools, this article introduced a simplified chiller plant calculation tool (SmartCP) to analysis the total energy performance, which was elaborated from three aspects: tool architecture, method and case-study verification. The front end of the tool was developed as a webpage, with capabilities to open a personal account, import basic case parameters and calculate the energy performance of a chiller plant. The back end of the tool included a database and calculation module to store chiller plant device parameters for computation purposes. The multiparameter fitting method was adopted as the primary method to establish chiller plant models. Based on the fitting coefficients and designed parameters, the tool computed the energy consumption, annual chiller plant efficiency (ACPE), real part-load performance value (RPLV) and energy costs. Finally, comparing the calculation results of SmartCP to those of TRACE 700 and EnergyPlus in real cases, it was found that the energy consumption error was within the acceptable range. In the first case, the relative errors of the annual total energy consumption, chiller consumption, and pump energy consumption were within 2%, while the error of the hourly energy consumption was within 9%. It was also found that the annual energy consumption error was less than 6% in the second case.