| 英文摘要 |
Air conditioning and refrigeration equipment have been used frequently and vastly, such as air conditioner and refrigerator. In the past, the types of conventional refrigerants were chlorofluocarbons (CFCs), whereas CFCs were validated that they can break the ozonosphere. Therefore, environmental refrigerants were launched to replace CFCs. In practice, hydrofluorocarbons (HFCs) are one of environmental refrigerants which are quite stable under normal temperature or pressure. However HFCs still possess hazardous characteristics of explosion with various environmental conditions, such as temperature, humidity, and pressure. This study investigated the flammable characteristics of R–134, cyclopentane, and R–600a, generic types of environmental refrigerants. Especially, we focus on the effects of flammability or explosion under normal temperatures and pressures. The experimental results revealed that only R–600a has explosion properties under normal pressure. The explosion limits of R–600a were 1.5–9 vol% at normal temperature. The maximum explosion pressure and maximum rate of pressure rise of R–600a were 8.8 bar and 364 bar/s, respectively. The value of explosion index (KG) of R–600a was 982.8, which was classified as the most violent in terms of explosive phenomenon St–3. The explosion limits of cyclopentane were 1.3–7.0 vol%. Its explosion pressure and maximum rate of pressure rise were 6.5 bar and 260.0 bar/s. Furthermore, R–134a did not demonstrate explosion phenomena under normal pressure and temperature. Based on the basic parameters, three different inert gases were used (nitrogen, carbon dioxide and steam) to test the inerting effect. From the results, CO2 is better than N2 and steam. However, CO2 was an asphyxiating gas. If CO2 used in the factory, we need to provide the safety system with protection mechanism. This study could determine the explosion behaviors to provide related parameters for storage and recycling with the use of R–134a, cyclopentane, and R–600a to avoid unacceptable disasters from occurring.
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