Which of the following is NOT a consequence of higher than normal head pressure?

Higher than normal head pressure influences the performance and efficiency of a refrigeration or air conditioning system in several significant ways. The correct answer is the choice indicating that it creates lower evaporator pressure, which does not occur in this situation.

When head pressure is elevated, it does not lead to a decrease in evaporator pressure. In fact, higher head pressure typically signifies that there is excess pressure in the condenser. This can impact the entire system, as the evaporator pressure is largely determined by the pressure at which the refrigerant evaporates – typically lower than the head pressure caused in the condenser. As the head pressure rises, the pressure differential across the evaporator increases, but it does not reduce the evaporator pressure itself. Instead, it may lead to inefficiencies, resulting in a scenario where the compressor struggles and becomes less effective.

Furthermore, the impact of higher head pressure leads to reduced compressor capacity, increased power consumption, and can also be detrimental to the compressor valves and lubrication. Each of these consequences stems from the physical principles related to how pressure affects fluid dynamics within the system.

By recognizing that higher head pressure actually contributes to operational challenges rather than lowering evaporator pressure, one can better understand the implications of system pressures in cooling applications.