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EPA 608 Core Exam·Refrigeration Fundamentals

What is latent heat?

  1. AHeat that causes a temperature change
  2. Heat absorbed or released during a phase change without temperature change
  3. CHeat lost through insulation
  4. DHeat generated by the compressor

Correct answer

Heat absorbed or released during a phase change without temperature change

Why

Latent heat is heat absorbed or released when a substance changes phase (solid/liquid/gas) without changing temperature.

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

Exam-style practice question. Not an official EPA exam question.