If the suction pressure is 60 PSIG and the discharge pressure is 180 PSIG, what is the compression ratio?

To calculate the compression ratio in a system, you use the formula:

[ \text{Compression Ratio} = \frac{\text{Discharge Pressure}}{\text{Suction Pressure}} ]

In this case, the suction pressure is given as 60 PSIG, and the discharge pressure is 180 PSIG. However, it's important to account for the fact that PSIG indicates pressure relative to atmospheric pressure. Therefore, we first convert these pressures to absolute pressures by adding atmospheric pressure (approximately 14.7 PSIA) to the PSIG values:

• Suction Pressure: 60 PSIG + 14.7 = 74.7 PSIA

• Discharge Pressure: 180 PSIG + 14.7 = 194.7 PSIA

Now we can calculate the compression ratio:

[ \text{Compression Ratio} = \frac{194.7}{74.7} \approx 2.605 ]

This result is approximately 2.6 to 1, which is represented in the given choices. Therefore, the correct choice reflects the closest calculation, confirming the value of the compression ratio as 2.6 to 1.

Understanding the compression ratio is essential in fields such as engineering and