Final answer:
The superheat for an R-22 heat pump operating in the cooling mode with the given conditions is 11°F, which is the difference between the measured suction line temperature and the saturation temperature at the compressor's suction pressure.
Step-by-step explanation:
The subject of this question is engineering, specifically related to heat pumps and refrigeration systems. Understanding the superheat of a refrigerant within a heat pump system is essential for ensuring the system operates efficiently and without damage.
In this scenario, the superheat is calculated by subtracting the saturation temperature associated with the true suction pressure from the measured temperature of the refrigerant. Assuming refrigerant R-22, the saturation temperature at 70 psig is approximately 42°F. Therefore, the superheat would be calculated as follows:
Measured Temperature - Saturation Temperature = Superheat
53°F - 42°F = 11°F
The correct answer is option a) 11°F, which is the superheat of the refrigerant at the outlet of the evaporator in the cooling mode for the given conditions.
The superheat is the difference between the actual temperature of the refrigerant vapor and its saturation temperature at a given pressure.
To calculate the superheat in this scenario, we need to determine the saturation temperature of R-22 at 70 psig. Using a pressure-temperature chart for R-22, we find that the saturation temperature at 70 psig is approximately 59°F.
Given that the suction line temperature is measured at 53°F, we can calculate the superheat by subtracting the saturation temperature from the measured temperature: 53°F - 59°F = -6°F. However, since superheat can only be positive, we take the absolute value: |-6°F| = 6°F.
Therefore, the superheat is 6°F.