Which of the following does not increase compressor surging?

To understand why decreasing the evaporator temperature does not increase compressor surging, it's important to recognize what compressor surging entails. Compressor surging is an unstable operating condition that occurs when the compressor experiences a reduction in airflow, leading to fluctuations in pressure and can cause damage to the system.

When the evaporator temperature is decreased, the refrigerant can absorb more heat. This typically results in an increase in the pressure in the evaporator, which means that the vapor entering the compressor is typically at a higher density and can improve the efficiency of the system. By allowing the compressor to operate more smoothly and efficiently, this change in temperature can help prevent the conditions that lead to surging.

In contrast, the other options mentioned—lowering the compression rational speed, increasing the discharge pressure, and increasing the suction pressure—can lead to situations where the flow of refrigerant may become unstable, increasing the potential for surging. Each of these conditions might create a scenario where the compressor is unable to handle the demand, leading to airflow disruptions that could result in surging.

Thus, the action of decreasing the evaporator temperature actually enhances the compressor's operation, reducing the likelihood of surging, which makes it the correct choice in this context.