成果報告書詳細
管理番号20150000000199
タイトル*平成26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2015/7/18
報告書年度2014 - 2014
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
・事故シナリオの検討に基づくハザード評価(実験室規模の燃焼試験で得られたKG値による実環境下での影響を評価する方法の検討)
・爆発影響評価(R1234ze(E)の火炎速度、燃焼速度、爆発強度指数KG値の燃焼特性評価)
・爆発強度影響評価(有効放散口面積の実験的評価)
(2)微燃性冷媒の過剰なエネルギーによる燃焼爆発評価
・微燃性冷媒の自然発火特性に対する水分、金属片などの影響評価
・アンモニアを中心とする他の可燃性ガスと微燃性冷媒との燃焼特性比較
(3)サービス・据え付け時の安全性評価
・市販オイルライターによる滞留A2L冷媒への着火可能性評価
(4)多室型空調機の急速漏洩を想定した安全性評価
・オイルライターを着火源とした場合の、容器内の温度および圧力上昇の計測
英文要約1) Physical Risk Assessment of Low Flammable Refrigerant Combustion (AIST)
a) Combustion and explosion assessment:
a-1) Hazard assessment based on accident scenario: The evaluation procedure to estimate reduction effect of the severity of deflagrations caused by combustible A2L refrigerants in full-scale environment, has developed by define the relationship between reduced pressure and venting space in the room with the help of the venting design.
a-2) Explosion hazard assessment: In addition to R32 and R1234yf, R1234ze(E) was included in assessment medium, and the flammability in the presence of elevated temperatures and moisture was experimentally investigated.
a-3) Explosion severity evaluation: According to the venting design for explosion protection, the reduced pressure effect due to the presence of opening in the room was studied and effective area of venting was experimentally evaluated under the presence of various vent shapes: circle, square, and rectangles with different ratio of long side and short side.
b) Combustion and explosion by excess energy: We employ an autoignition test according to the ASTM E 659 standard for flammable gases in the presence of moisture or some metals. To achieve practical application of A2L/2L refrigerants and enhance safety, explosion characteristics with other flammable gases were listed with reference to KG and they were compared with the those of A2L refrigerants obtained under elevated temperature and wet conditions at section a-2. It was cleared that KG values of A2L refrigerants obtained under such conditions were still small and the same as or less than that for ammonia.
2) Physical hazard evaluation in the service and maintenance (Tokyo University of Science):
We experimentally evaluated the possibilities of ignition and flame propagation of A2L refrigerant assuming the situation in which a service operative used a portable kerosene cigarette lighter for smoking in the accumulated A2L refrigerant. The ignition and flame propagation to accumulated R32 was confirmed with a surrogate source of ignition for usual generation by rubbing the flint wheel. This is because the mixture in the windbreak of the lighter only consisted of the lighter fuel and air under the present leak rate even if the kerosene cigarette lighter was located in the accumulated R32. In short, there is a real possibility of ignition and flame propagation when a kerosene cigarette lighter is used in accumulated R32.
3) In situation that A2L refrigerant was installed to a VRF system (Tokyo University of Science):
We examined the temperature and pressure rise originated from the combustion of A2L refrigerant by the kerosene cigarette lighter collaborating with the above subtheme (physical hazard evaluation in the service and maintenance). Under the present experimental condition, for pressure rise, no catastrophic increase of pressure originated from the combustion of R32 or R1234yf was confirmed.
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