low GWP, ASHRAE class 3, data collection system, leak concentration
Environmental regulations are increasingly restricting the use of traditional high global warming potential (GWP) fluorinated refrigerants (1). Hydrofluorocarbons or HFCs are fluorinated refrigerants with zero ozone depletion potential (ODP). They are typified by having good shelf and use stability, material compatibility, adequate capacity and generally good performance across a range of operating conditions all while being non-flammable. However, due to the high GWP (>1000-5000), they are losing favor in the marketplace. Many international equipment standards (IEC 60335-2-24, IEC 60335-2-40, IEC 60335-2-89, etc.) and installation standards (ISO 5149) are being revised to further enable use of lower GWP, 0 ODP refrigerants which are flammable (2,3,4,5) Therefore, understanding how different classes of flammable refrigerants leak and pool is a key input to equipment safety standard design. While there have been many recent studies focusing on ASHRAE class 2L (low) flammability refrigerants not much work has been done reviewing ASHRAE class 3 (high) flammable refrigerants, such as propane (6). Therefore, this work was to review how a hydrocarbon, namely propane, could leak from refrigerant A/C equipment and the size and potential concentration pattern from such a leak. Due to the size and scope of this project, it was divided into three parts. The first part of this project was to construct a typical room with an installed packaged heating/air-conditioning unit (PTAC, frequently used in motels) and set-up data collection equipment to reliably collect point concentration and area (room) concentration data. The next part of the project will focus on reviewing leak patterns from equipment using thermal imaging. The third and final part of the project will connect the leak concentrations and patterns together to provide an overview of real-time leakage of propane from an installed PTAC.