Environmental Protection Agency (EPA) MVAC Certification

What effect do non-condensables have on discharge pressure in a refrigeration system?

1. Lower

2. Maintain

3. Higher

4. Stabilize

The correct answer is: Higher

Non-condensables, such as air or other gases that do not change phase in the condenser, have a significant impact on the discharge pressure in a refrigeration system. When non-condensables are present, they occupy space in the condenser, which effectively reduces the capacity of the system to dissipate heat. As a result, the refrigeration system has to exert more pressure to achieve the same level of heat removal. This increase in required pressure results in a higher discharge pressure. The addition of non-condensables means that the compressor has to work harder to achieve the desired performance, ultimately leading to increased discharge pressure. Increased pressures can also cause efficiency problems and may lead to overheating or increased wear and tear on system components. Understanding this relationship is crucial for maintaining optimal performance and efficiency in refrigeration systems, as well as for adherence to environmental regulations and best practices in HVAC operations.