313A Compressors & Condensers 2

Question 1

What is the function of the condenser in a refrigeration system?

Accepted Answer

To reject heat from the refrigerant to the ambient medium, condensing the refrigerant from vapour to liquid

Answer

The condenser rejects the heat absorbed in the evaporator plus the heat of compression to the outdoor air or cooling water, condensing the refrigerant vapour back into a liquid.

Question 2

What is the approach temperature of an air-cooled condenser?

Accepted Answer

The difference between condensing temperature and entering air temperature

Answer

Approach temperature is the difference between the condensing temperature (saturation temperature at condensing pressure) and the entering air dry-bulb temperature, and a low approach temperature indicates good heat transfer.

Question 3

What effect does dirty condenser coils have on a refrigeration system?

Accepted Answer

Higher discharge pressure, higher condensing temperature, and reduced system efficiency

Answer

Dirty condenser coils reduce airflow and heat transfer, causing the condensing temperature and discharge pressure to rise, which increases compressor work and reduces system efficiency and capacity.

Question 4

What type of condenser uses water as the heat rejection medium and is commonly used in large commercial systems?

Accepted Answer

Water-cooled condenser (shell-and-tube or plate heat exchanger)

Answer

Water-cooled condensers, such as shell-and-tube or brazed plate heat exchangers, use water from a cooling tower or municipal supply to reject heat from the refrigerant, offering high efficiency in large commercial applications.

Question 5

What is the purpose of non-condensable gas purging in a refrigeration system?

Accepted Answer

To eliminate air or nitrogen trapped in the system that raises condensing pressure and reduces efficiency

Answer

Non-condensable gases such as air or nitrogen do not condense and accumulate at the top of the condenser, artificially raising discharge pressure and reducing heat transfer efficiency.

Red Seal HVAC 313A Practice Test

Red Seal HVAC 313A Practice Test

313A Compressors & Condensers 2