Nate Electrical Practice Exam

Which factor increases the horsepower required per ton of cooling in an air conditioning system?

1. Increasing discharge pressure

2. Decreasing suction pressure

3. Both a and b

4. None of the above

The correct answer is: Both a and b

In an air conditioning system, the horsepower required per ton of cooling is influenced by various operational factors. One critical factor is the discharge pressure. As discharge pressure increases, the compressor must work harder to push the refrigerant through the system, thereby requiring more energy and increasing horsepower consumption. This is because the compressor handles the refrigerant at a higher pressure, which results in a greater load on the motor. Furthermore, decreasing suction pressure contributes to the need for more horsepower as well. Lower suction pressure indicates a reduced pressure at the intake of the compressor, which can lead to less efficient operation. The compressor has to operate longer or harder to achieve the desired cooling effect under these conditions, thus demanding more energy. When both discharge pressure increases and suction pressure decreases occur simultaneously, the overall system efficiency declines, resulting in a higher horsepower requirement per ton of cooling. Therefore, both factors indeed increase the horsepower required, validating the option that suggests both conditions have this effect.