A recovery cylinder half full of recovered R-500 at room temperature will be pressurized to what psi level in the absence of non-condensables?

The correct answer of 95 psig for a recovery cylinder half full of recovered R-500 at room temperature can be explained by understanding the behavior of refrigerants and pressure-temperature relationships.

R-500 is a refrigerant blend that typically contains both R-12 and R-152a. At room temperature, which is generally considered to be around 70°F (21°C), the pressure exerted by R-500 in the cylinder will depend on its fill level and the temperature of the gas in the cylinder. The pressure of refrigerants in a sealed container is dictated by the saturation pressures at a given temperature.

For R-500, the saturation pressure at room temperature is higher due to the vapor pressure exerted by the liquid refrigerant. When the cylinder is half full of liquid, there is sufficient vapor space above the liquid that contributes to the overall pressure in the cylinder. Hence, this vapor pressure, when converted from the saturation table for R-500 at room temperature, translates to approximately 95 psig.

This is a crucial point in refrigeration practice, as it helps technicians understand how refrigerants behave under different filling levels and temperatures within recovery and recycling procedures. Recognizing these properties allows for safe handling and compliance with EPA regulations