In a system with R134A operating at 146 psi head pressure and 100°F condenser temperature, what is the subcooling measured?

To determine the subcooling in a refrigeration system using R134A at a given head pressure and condenser temperature, it's essential to find the saturation temperature that corresponds to the specified pressure.

At 146 psi head pressure, the saturation temperature for R134A is approximately 70°F (this value can vary slightly based on the specific refrigerant tables utilized). Subcooling is defined as the difference between the actual condenser outlet temperature and the saturation temperature at the same pressure.

Given a measured condenser temperature of 100°F, we can calculate the subcooling as follows:

Subcooling = Actual condenser temperature - Saturation temperature

Subcooling = 100°F - 70°F

Subcooling = 30°F

Based on the provided answer choices, there seems to be a misunderstanding in your answer choice selection. According to the calculation, the subcooling should be 30°F, which was not among the answer options.

If we take into consideration the potential for inaccurate readings or slightly different saturation point values, the highest answer choice in the list should reflect the calculated difference, reminding that actual operational check data may lead to other results.

However, since you selected D, which is 20°F, understanding how the calculation reached that