How to choose the refrigerant of high and low temperature alternating heat and humidity test chamber

There are many kinds of refrigeration used in high and low temperature alternating heat and humidity test chambers. Different refrigerants have different uses and application ranges. Today, we will focus on the main refrigerants on the market.

First, low pressure high temperature refrigerant

The condensing pressure Pk ≤ 2 - 3 kg / cm (absolute), the evaporation temperature T0 > 0 ° C. For example, R11 (Freon 11, CFCL3, monofluoro, T0 = 23.7 ° C), R21, R114, T0 = 23.7 ° C. This type of refrigerant is suitable for use in centrifugal refrigeration compressors for air conditioning systems. Usually 30 ° C, Pk ≤ 3.06kg / cm.

Second, medium pressure temperature refrigerant

The condensing pressure Pk ≤ 20 kg/cm (absolute), 0 ° C > T0 > -60 ° C. Such as R717 (ammonia, NH3), R12, R22 (Freon 22, CHCLF2, difluorochloromethane), R502 (an azeotropic refrigerant, composed of R22 and R115 (pentafluoro-chloroethane, C2F5CL)), etc. Such refrigerants are generally used in conventional single-stage compression and two-stage compression piston refrigeration compressors.

Third, high pressure low temperature refrigerant

The condensing pressure Pk ≥ 20 kg / cm (absolute), T0 ≤ -70 ° C. Such as R23 (Freon 23, CHF3), R13 (CF3CL), R14 (CF4), carbon dioxide (CO2), R503, ethane, ethylene, etc., such refrigerants are suitable for the low temperature part of the cascade refrigeration unit or -70 ° C In the following cryogenic devices.

After reading the above content, we have learned about -70 °C high and low temperature alternating heat and humidity test chamber, high and low temperature damp heat test chamber, high and low temperature alternating test chamber, high and low temperature test chamber, fast temperature change test chamber, constant temperature and humidity test chamber. The high-temperature impact test chamber and the ultra-low temperature test chamber use the medium temperature refrigerant (R404A) in the high temperature part and the low temperature refrigerant (R23) in the low temperature part. Therefore, the refrigerant is very important for the high and low temperature alternating heat and humidity test chamber.