RSES Evaporator Systems 4

Question 1

What is the purpose of a suction line accumulator installed between the evaporator and compressor?

Accepted Answer

To prevent liquid refrigerant slugs from reaching the compressor

Answer

A suction line accumulator traps liquid refrigerant and oil, releasing only vapor to the compressor to prevent liquid slugging damage.

Question 2

Which factor most significantly affects the air-side heat transfer performance of a fin-and-tube evaporator?

Accepted Answer

Fin spacing and fin surface cleanliness

Answer

Fin spacing determines airflow resistance and surface area, while cleanliness ensures that the full fin surface area is available for heat exchange.

Question 3

A technician installs a TXV with a remote sensing bulb. Where should the bulb be clamped for proper superheat sensing?

Accepted Answer

On the suction line outside the refrigerated space, after the evaporator outlet

Answer

The TXV sensing bulb must be clamped on the suction line after the evaporator outlet to sense actual refrigerant superheat leaving the evaporator.

Question 4

What effect does an excessively high evaporator fan speed have on evaporator performance in a low-humidity storage application?

Accepted Answer

Increased moisture removal from stored product due to greater air-to-coil contact

Answer

Higher fan speed increases the rate at which moist air contacts the cold coil, causing more moisture to condense and freeze on the coil and dehumidify the stored product.

Question 5

During hot-gas defrost of a low-temperature evaporator, the system pressure may rise significantly. What component protects the low-side from excessive pressure?

Accepted Answer

A defrost pressure-relief or pressure-limiting valve on the evaporator outlet

Answer

A pressure-limiting or defrost relief valve vents excess pressure from the evaporator to the suction line or condenser to prevent low-side pressure from exceeding safe limits.

(RSES) Refrigeration Service Engineers Society Certification Practice Test

(RSES) Refrigeration Service Engineers Society Certification Practice Test

RSES Evaporator Systems 4