Type III — Low-Pressure第 189 / 240 题
Which refrigerant is a CFC once widely used in low-pressure chillers and now available only as reclaimed stock?
a.CFC-11
b.HFC-134a
c.HFC-410A
d.HCFC-22
解析
CFC-11 (R-11) was the classic low-pressure chiller refrigerant, but U.S. CFC production ended January 1, 1996, so it is now available only from recovered and reclaimed stock. R-134a, R-410A, and R-22 are not low-pressure CFC chiller refrigerants. This scarcity makes careful recovery of R-11 especially important.
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