ESCO Air Conditioning Practice Exam 2026 – Complete Study Resource

To determine the pressure of R-134a when it exits the condenser as a subcooled liquid, you start with the conditions at which the vapor enters. R-134a enters the condenser at 124 psiG and 100°F, where it begins to lose heat and condense into a liquid.

As the refrigerant transitions from vapor to liquid, it will condense at a pressure that corresponds to the saturation temperature. After achieving the phase change, the liquid is then further cooled to achieve the subcooled temperature, which in this case is 20°F lower than the saturation temperature.

For R-134a, at 124 psiG (which is approximately 130 psia), the saturation temperature can be referenced from refrigerant property tables. It is important to note that for a refrigerant like R-134a, the saturation temperature at about 124 psi is approximately 100°F.

Once the refrigerant condenses and is then cooled, the pressure of a subcooled liquid will typically not be significantly lower than the saturation pressure, but it does decrease slightly due to the cooling phase. In this scenario, a subcooled liquid at a condition of 20°F below saturation will, therefore, exist at a