HO-18-C032 -- CFD Modeling of Flammable Refrigerant Leaks inside Machine Rooms- Emergency Ventilation Rate for Different Size Chillers PDF

Computational fluid dynamics (CFD) simulations were undertaken to quantify ventilation dilution requirements needed for mitigating flammability risks during leaks of flammable refrigerants from different size chillers inside machine rooms in extension of the prior work for very large chillers. For this study, a 376 m³ machine room configuration was modeled using CFD to simulate major flammable refrigerant leaks from a chiller with refrigerant charge less than 600 kg. Three different mildy flammable refrigerants with various leak rates and various air ventilation rates were evaluated to understand dilution requirements to prevent significant refrigerant flammable mass accumulation. These results will be discussed in light of previously published machine room ventilation requirements for mitigating sustained leaks from large chillers, and used to establish a generalized relationship for the emergency ventilation rate needed for mitigating risks for major refrigerant leaks inside machine rooms for the full range of refrigerant charges.