The compression ratio under which a refrigeration compressor operates is?

The correct choice reflects the proper way to calculate the compression ratio of a refrigeration compressor. The compression ratio is fundamentally the relationship between the pressure at which the refrigerant is discharged by the compressor and the pressure at which it is drawn into the compressor.

When considering the compression ratio, using absolute pressures is essential. Absolute pressure accounts for atmospheric pressure in the calculations, which is important in ensuring the accuracy of the compression ratio, especially for systems operating under varying atmospheric conditions. This means both the discharge pressure and the suction pressure must be measured from an absolute scale, eliminating any discrepancies due to atmospheric pressure changes.

By dividing absolute discharge pressure by absolute suction pressure, you obtain a true representation of the compression ratio. This measure is vital because it impacts the performance, efficiency, and capacity of the refrigeration system. The other options do not adequately incorporate absolute pressure, making them less suitable for accurately defining the compression ratio and could lead to potential misunderstandings of how compressors function under different operating conditions.