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R134a and R407C
These refrigerants are used mainly for air conditioning and substitution of R22 in many applications. R134a has a relatively low pressure and, thus, about 50% more compressor displacement is necessary, when compared to R22 and this can make a compressor more costly. Large tube components and, as consequence, increases the cost of the system. R134a is very successfully used in screw compressors Chillers, where short tube, minimize costs associated with large tube. R134a also finds a niche where additional high condensing temperatures are needed and in many of transport applications.
R407C is a zeotropic mixture consisting of 23% R32, 25% R125 and 52% R134a. It has properties similar to those of R22, and for this reason, saw widespread use in Europe due to the rapid R22 phase. Its glide and heat transfer characteristics, as a rule, to punish the performance of the system, even though the counter-flow heat exchange can bring some benefits with пластинчатые heat exchangers.
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