Paper Conference

Proceedings of SimBuild Conference 2004: 1st conference of IBPSA-USA


Simulation for Refrigerant Charge Diagnostics in Supermarket Applications

Kiengkrai Assawamartbunlue, Michael Brandemuehl
Sirindhorn International Institute of Technology, Thailand
University of Colorado, Boulder, CO, USA

Abstract: This paper describes a computer program, DRSSIM, that can predict liquid refrigerant level in the receiver of a distributed refrigeration system in a supermarket. DRSSIM has been developed to be further used for refrigerant leakage detection and diagnostic technique in the system. Unlike a simple refrigeration system commonly implemented in HVAC application, the distributed refrigeration system in a supermarket is more complicated. It can consist of several compressors, condensers, and racks of refrigerated cases. An important component that makes the system different from the simple refrigeration system is the presence of a high-side liquid receiver, which affects the balance of the whole system. Modeling this complicated system requires several techniques to reduce calculation time and be suitable for fault detection. The component and system models developed as parts of DRSSIM are steady-state models based on the first-principle engineering equations. DRSSIM can predict the liquid refrigerant level in the receiver with the root mean square error of 1.3%. DRSSIM also has a modular design so that the user can easily add or modify refrigeration components or system configuration.