In the context of energy conservation and reduction of greenhouse gas emissions, there has been considerable attention focused on the application of the natural refrigerant R-290 (propane) in residential air conditioning (AC) systems. An ignition event can occur once R-290 is released from residential AC systems and encounters an ignition source within an indoor environment. For studying the application safety of cabinet AC systems, this paper employs Computational Fluid Dynamics (CFD) to simulate the release of R-290 in residential rooms and derive the real-time flammable volume during release. The most hazardous cases are identified by analysing the effects of practical influences such as release rate, release location, air supply velocity, room size, and furniture arrangement. On this basis, the frequency of ignition events is calculated under the selected leak hole in conjunction with a quantitative risk assessment methodology. The results show that when the airflow is off, the most hazardous case is the flow of refrigerant into the room after being obstructed by the enclosure, whereas when the airflow is on, the most hazardous case is the direct release of refrigerant from the air supply outlet into the indoor space. With the charge limits required by the IEC standard, the frequency of indoor ignition events in R-290 cabinet AC systems does not exceed 10 triennially. This study investigates the flammable volume and the frequency of ignition events associated with R-290 leakage, which is useful for analysing the safety measures for R-290 applications in residential AC systems.

中文翻译：

---

R-290在住宅空调系统中应用安全性的调查


在节能和减少温室气体排放的背景下，天然制冷剂R-290（丙烷）在住宅空调（AC）系统中的应用受到了相当多的关注。一旦 R-290 从住宅空调系统中释放出来并在室内环境中遇到点火源，就会发生点火事件。为了研究柜式空调系统的应用安全性，本文采用计算流体动力学（CFD）模拟R-290在住宅房间中的释放，并得出释放过程中的实时可燃体积。通过分析释放速率、释放位置、送风速度、房间大小和家具布置等实际影响的效果来确定最危险的情况。在此基础上，结合定量风险评估方法计算选定泄漏孔下的着火事件频率。结果表明，当气流关闭时，最危险的情况是制冷剂被外壳阻挡后流入房间，而当气流打开时，最危险的情况是制冷剂从送风口直接释放出口进入室内空间。根据 IEC 标准要求的充电限制，R-290 柜式交流系统中室内起火事件的频率每三年不超过 10 次。本研究调查了与 R-290 泄漏相关的可燃量和点火事件的频率，这对于分析住宅空调系统中 R-290 应用的安全措施非常有用。