How is the compression ratio defined in refrigeration terms?

The compression ratio in refrigeration systems is defined as the ratio of the absolute discharge pressure to the absolute suction pressure. This concept is critical in understanding how efficiently a refrigeration cycle operates.

In a refrigeration cycle, the compressor takes in refrigerant vapor at a low pressure (suction pressure) and compresses it to a higher pressure (discharge pressure). The compression ratio indicates how much the vapor is compressed during this process. A higher compression ratio may indicate either a higher level of compression or a greater difference between the suction and discharge pressures.

This ratio impacts several performance metrics of the refrigeration system, including the efficiency and energy consumption of the compressor. By evaluating the compression ratio, technicians can diagnose system performance issues and optimize the operation of the refrigeration unit.

The other options relate to different concepts that, while relevant in the context of refrigeration and HVAC systems, do not specifically define the compression ratio in terms of pressures within the cycle. For example, horsepower to BTU relates to the efficiency of the compressor in terms of energy output, while inrush current versus steady-state current pertains to electrical characteristics of motors.