Question

If an R-22 refrigeration system has its air-cooled condensing unit on a 100 F roof, with a discharge pressure of 260PSIG and the condenser outlet temperature (Liquid line) is 105 F, with how much sub cooling is the condenser operating? a. 30F b.15F c.100F d.130F Please explain how to solve

Answer 1

Subcooling = condensation temperature - liquid line temperature.

we have liquid line temperature = 105F

For the condensation temperature, we have to look at P-T relationship (pressure-temperature relationship of R22 refrigeration).

The standard chart for R-22 refrigeration system (which can be easily found on google, I cannot post it now as it might be considered plagiarism) states that 260 PSIG corresponds to 120 F temperature.

Hence, condenser temperature = 120F

subcooling= 120-105F

= 15F (a)