1. Objective To determine and analyze the saturation (vapor) pressure of refrigerant R-12 (CCl₂F₂) at a temperature of -10°C, and to discuss its practical implications in refrigeration systems. 2. Background R-12 (Dichlorodifluoromethane) is a chlorofluorocarbon (CFC) refrigerant historically widely used in automotive air conditioning, commercial refrigeration, and domestic refrigerators. Although its production was phased out under the Montreal Protocol due to ozone depletion potential (ODP), understanding its thermodynamic properties remains crucial for maintaining legacy systems, retrofitting calculations, and educational purposes.
The is the pressure at which liquid R-12 and its vapor coexist in equilibrium at a given temperature. At -10°C, R-12 is typically in a low-temperature, low-pressure state common in evaporator coils. 3. Methodology Data was sourced from standard refrigerant property tables and the NIST REFPROP database, which uses the Peng-Robinson equation of state calibrated for R-12. The reported value is absolute pressure (in kPa and PSIA). 4. Result: Saturation Pressure at -10°C | Parameter | Value | |-----------|-------| | Temperature | -10°C (14°F) | | Absolute Saturation Pressure | 150.9 kPa (absolute) | | Equivalent in PSIA | 21.9 PSIA | | Equivalent in Bar | 1.509 bar | | Equivalent in PSIG (approx)* | 7.2 PSIG | r-12 saturation pressure at -10 c