Design, simulation, and construction of a hot-gas bypass chiller for a commercial scale psychrometric coil testing facility

Abstract

In recent years, there has been a large effort from industry and researchers to improve the efficiency of HVAC&R systems. At Oklahoma State University (OSU), the Building & Environmental Systems Research Group (BETSRG) has been developing a psychrometric coil testing facility to test commercial fin and tube heat exchangers. The facility has an array of subsystems; this thesis is focused primarily on the Hot Gas Bypass Chiller (HGBC) subsystem. The objective is to provide a source of cooling capacity for the pumped refrigerant loop and develop a controls strategy that will allow the chiller to adjust to quick changes in test points with minimal overshoot and settling time. To achieve the objective, a steady-state model was developed first for component sizing and parametric analysis. And second, development of a dynamic model to determine an optimal controls strategy for the HGBC and to establish a workflow on how to implement the controls strategy in the field.