RSES Refrigeration Fundamentals & System Components 3

Question 1

What condition is indicated when the suction pressure is lower than normal and the discharge pressure is also lower than normal?

Accepted Answer

Refrigerant undercharge or low suction load

Answer

Low suction and low discharge pressures together typically indicate a refrigerant undercharge or insufficient heat load on the evaporator.

Question 2

In a hermetic compressor, the motor and compressor are:

Accepted Answer

Enclosed in the same sealed housing sharing refrigerant

Answer

A hermetic compressor seals both motor and compressor in one welded shell, with suction gas cooling the motor windings.

Question 3

The coefficient of performance (COP) of a refrigeration system is calculated as:

Accepted Answer

Refrigerating effect divided by work input to the compressor

Answer

COP = Q_evaporator / W_compressor, expressing how many units of heat are moved per unit of energy consumed.

Question 4

Which refrigerant is classified as an HFC (hydrofluorocarbon) with zero ozone depletion potential?

Accepted Answer

R-134a

Answer

R-134a is an HFC containing no chlorine, giving it zero ozone depletion potential (ODP), unlike older CFC and HCFC refrigerants.

Question 5

An oil separator in a refrigeration system is located:

Accepted Answer

Between the compressor and condenser

Answer

Oil separators are installed in the discharge line to capture oil carried over from the compressor before it reaches the condenser and evaporator.

(RSES) Refrigeration Service Engineers Society Certification Practice Test