3 Refrigerant Fundamentals and Practices Free Online FlashCards

How does a refrigerant transfer heat as it changes phase?

A refrigerant absorbs heat as it evaporates and releases heat as it condenses.

What does a refrigerant P–T chart relate?

For a specific refrigerant, each saturation pressure corresponds to a saturation temperature. A P–T chart lets you convert between those values.

What can pressure indicate in a two-phase refrigerant system?

When liquid and vapor coexist in equilibrium, system pressure indicates the refrigerant’s saturation temperature. It does not necessarily indicate the pipe or appliance temperature.

Can a P–T chart alone diagnose a refrigeration fault?

A P–T chart alone does not reveal system charge or diagnose a fault. Interpret pressure with temperatures, operating conditions, airflow, and other measurements.

How is superheat assessed?

Compare the vapor’s actual temperature with the saturation temperature at the same pressure.

How is subcooling assessed?

Compare the liquid’s actual temperature with the saturation temperature at the same pressure.

Which saturation points are used for zeotropic-blend calculations?

Use the dew-point value for saturated vapor and superheat calculations, and the bubble-point value for saturated liquid and subcooling calculations.

What does refrigerant recovery mean?

Recovering means removing refrigerant from an appliance and storing it in an external container; the refrigerant need not be tested or cleaned.

What distinguishes refrigerant recycling from reclamation?

Recycling cleans recovered refrigerant for reuse, generally in equipment belonging to the same owner, but does not bring it to reclamation specifications.

What does refrigerant reclamation involve?

Reclamation reprocesses recovered refrigerant to applicable purity specifications and verifies it through the prescribed analysis.

Why should refrigerants not be mixed during recovery?

Do not mix refrigerants. Mixed or unidentified refrigerant can be difficult to reuse and may require special handling.

How do recovery evacuation and system evacuation differ?

Recovery evacuation removes refrigerant to the applicable regulatory level before equipment is opened. System evacuation after repair removes air and moisture from the opened circuit.