- APressure decreases
- Pressure increases
- CPressure stays the same
- DPressure fluctuates randomly
Correct answer
Pressure increases
Why
Refrigerant pressure and temperature have a direct relationship - as temperature increases, pressure increases (pressure-temperature relationship).
The concept behind this question
The refrigeration cycle moves heat rather than creating cold, and every question about pressures and temperatures comes back to it. The compressor raises the refrigerant's pressure and temperature; the condenser rejects heat and the refrigerant becomes liquid; the metering device drops the pressure; the evaporator absorbs heat from the space and the refrigerant boils back to vapour. Because pressure and temperature are related for a saturated refrigerant, a pressure reading plus a P/T chart tells you the saturation temperature — which is the basis for measuring superheat and subcooling.
More questions on this topic
- Which component separates the high-pressure and low-pressure sides of a refrigeration system?
- What is the function of the compressor in a refrigeration system?
- What is the function of the evaporator in a refrigeration system?
- What is the function of the condenser in a refrigeration system?
- What is the 'superheat' in a refrigeration system?
- What is 'subcooling' in a refrigeration system?
Exam-style practice question. Not an official EPA exam question.