RSES Condenser Systems 2 — Questions and Answers
Question 1: What is the primary effect of non-condensable gases on condenser performance?
- They increase subcooling
- They raise condensing pressure and reduce capacity (Correct answer)
- They lower the condensing temperature
- They improve heat transfer coefficients
Correct answer: They raise condensing pressure and reduce capacity
Non-condensable gases occupy space in the condenser, raising condensing pressure and reducing the effective heat transfer surface.
Question 2: In an evaporative condenser, what is the purpose of the water distribution system?
- To cool the refrigerant directly
- To wet the coil surface for evaporative cooling (Correct answer)
- To maintain refrigerant pressure
- To filter airborne contaminants
Correct answer: To wet the coil surface for evaporative cooling
The water distribution system keeps the condenser coil surface wet so that evaporation of water removes heat from the refrigerant.
Question 3: Which factor most directly determines the condensing temperature in an air-cooled condenser?
- Compressor discharge pressure only
- Ambient dry-bulb temperature (Correct answer)
- Ambient wet-bulb temperature
- Refrigerant subcooling level
Correct answer: Ambient dry-bulb temperature
Air-cooled condensers reject heat to ambient air, so the ambient dry-bulb temperature sets the minimum achievable condensing temperature.
Question 4: A condenser coil with fouled fins will most likely result in which condition?
- Lower condensing pressure
- Higher suction pressure
- Higher condensing pressure and temperature (Correct answer)
- Lower compressor amp draw
Correct answer: Higher condensing pressure and temperature
Fouled fins restrict airflow and reduce heat transfer, causing the condensing pressure and temperature to rise.
Question 5: What does 'condenser split' refer to in field diagnostics?
- The temperature difference between inlet and outlet refrigerant
- The difference between condensing temperature and leaving air temperature (Correct answer)
- The pressure difference across the condenser coil
- The ratio of liquid subcooling to condensing pressure
Correct answer: The difference between condensing temperature and leaving air temperature
Condenser split is the difference between the refrigerant condensing temperature and the temperature of air leaving the condenser.
Question 6: In a shell-and-tube water-cooled condenser, refrigerant typically flows:
- Inside the tubes
- Through the shell side around the tubes (Correct answer)
- Through a separate plate circuit
- Counter-current inside the tubes only
Correct answer: Through the shell side around the tubes
In most shell-and-tube condensers, refrigerant flows through the shell while cooling water flows inside the tubes.
Question 7: Which refrigerant property most influences the required condenser surface area for a given load?
- Viscosity at suction conditions
- Latent heat of vaporization at condensing pressure (Correct answer)
- Specific heat of liquid refrigerant
- Vapor density at suction pressure
Correct answer: Latent heat of vaporization at condensing pressure
A refrigerant with higher latent heat at condensing conditions can reject more heat per unit mass, requiring less surface area for the same load.
RSES Condenser Systems 2
What is the primary effect of non-condensable gases on condenser performance?