A Study of Refrigerant Dispersion in Occupied Spaces Under Parametric Variation

While an understanding of the dispersion of refrigerant in occupied spaces is important to ASHRAE Standard 15-2010's objective of ensuring the safety of occupants for spaces in which HVAC&R systems are installed, only simplified models are generally used to describe refrigerant leakage phenomena because of their complexity. This paper describes some studies of the transient refrigerant dispersion behavior from variations in the leakage rate, the exhaust ventilation rate, and the height of a wall undercut that could be used to develop improved models of the dynamics of refrigerant leaks. The results indicate that well-mixed models do not accurately describe the refrigerant distribution in many cases because of stratification, and that this stratification may be used in tandem with vent placement to ensure that refrigerant concentration levels do not exceed safety limits.