成果報告書詳細
管理番号20140000000469
タイトル*平成25年度中間年報 「高効率ノンフロン型空調機器技術の開発 冷媒の性能、安全性評価 微燃性冷媒の燃焼・爆発性評価と空調機器使用時のリスクアセスメント」(H23-H27)
公開日2014/8/20
報告書年度2013 - 2013
委託先名学校法人東京理科大学
プロジェクト番号P11008
部署名環境部
和文要約微燃性冷媒を使用した空調機について、着火事故が発生した場合の人的・物的な危害度(フィジカルハザード)を明確化するために、下記研究項目を実施した。
(1)微燃性冷媒の燃焼爆発影響評価
・燃焼実験
・湿度・温度による燃焼影響評価
・爆発強度指数KG値の評価
・A2L/2L冷媒の燃焼シミュレーションの検討
(2)微燃性冷媒の過剰なエネルギーによる燃焼爆発評価
・燃焼特性の整理と他媒体との比較
・自然発火温度
(3)サービス・据え付け時の安全性評価
・ターボライター使用時の着火危険性
(4)多室型空調機の急速漏洩を想定した安全性評価
英文要約(1) Physical Risk Assessment of Low Flammable Refrigerant Combustion (AIST)
(a) Combustion and explosion assessment: To observe and evaluate the effect of buoyancy on the flammable properties of A2L refrigerants, a large-volume spherical vessel with a volume of 0.524 m3 has been prepared, and the flame propagation behaviors of A2L refrigerants were observed using a high-speed video camera. In case of R32 phi (Fuel-Air equivalent ratio) 1.2 condition, the flame expanded while slowly climbing upward. The flame front was distorted under the influence of buoyancy and viscosity. For R1234yf phi1.35, no clear and smooth flame front was observed in the large vessel, but a smooth and clear flame front was observed in an alternative compact elongated cylindrical vessel (10cm in inner diameter and 20cm in length). Flammability tests under dry and wet conditions were conducted for R32 and R1234yf for the effects of temperature and humidity on the flammability of some A2L/2L refrigerants.
(b) Combustion and explosion by excess energy: As an implicit but useful reference for the potential risk of explosion and detonation, flammable parameters on peak pressure (Pmax), KG, burning velocity, and flammability and detonation limits for mixtures with air were summarized with reference to KG. It was cleared that KG values of 9 for R32 and 6 for R1234yf were considerably small and the same as or less than that 10 for ammonia. To estimate the autoignition characteristics of A2L/2L refrigerants, a testing apparatus was installed according to the ASTM E 659. The autoignition characteristics of A2L/2L refrigerants and other flammable gases such as propane and ammonia will be compared in next FY.
(2) Physical hazard evaluation in the service and maintenance (Tokyo University of Science)
In the case that a piezo gas lighter was used, no ignition case was confirmed. In the case a turbo gas lighter, though the ignition and a little flame propagation around the outlet of a turbo lighter was confirmed, the flame went out soon and the serious pressure of blast wave and the temperature increase were not observed.
(3) In situation that A2L refrigerant was installed to a VRF system (Tokyo University of Science)
We focused on to clarify the properties of combustion behaviors originated from the combustion of A2L refrigerant by a series of labo-scale experiments. For R1234yf, influence of humidity on the combustion behavior was significantly confirmed. In the present experiment, apparent increase of blast wave and temperature were observed in the case of 750 mm and 500 mm of leak height. It was considered to be that the scale of flame propagation and the significant increases of these parameters depend on the amount of refrigerant that exceeded LFL located above an ignition source. However, at most, the pressure of blast wave merely corresponds to the phenomena that the acrylic board of 10 mm of thickness was lifted a little.
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