Q1: 1. What does the psychrometric chart help determine in Refrigeration & Air-Conditioning?

• A) Temperature
• B) Humidity
• C) Enthalpy
• D) All of the above

Q2: 2. Which property is represented on the x-axis of a psychrometric chart?

• A) Enthalpy
• B) Humidity ratio
• C) Dry-bulb temperature
• D) Wet-bulb temperature

Q3: 3. On a psychrometric chart, what does the diagonal lines represent?

• A) Isothermal lines
• B) Adiabatic lines
• C) Constant humidity lines
• D) Saturation lines

Q4: 4. Which point on the psychrometric chart represents the maximum amount of moisture air can hold at a given temperature?

• A) Dew point
• B) Wet bulb temperature
• C) Saturation
• D) Enthalpy

Q5: 5. What is the significance of the intersection of the dry-bulb temperature line and the constant humidity ratio line on a psychrometric chart?

• A) Dew point temperature
• B) Enthalpy
• C) Relative humidity
• D) Specific volume

Q6: 6. In a real-life scenario, a refrigeration system is operating at 40% relative humidity and 25°C dry-bulb temperature. What is the dew point temperature?

• A) 18°C
• B) 20°C
• C) 22°C
• D) 24°C

Q7: 7. What does the area under the saturation curve on a psychrometric chart represent?

• A) Specific volume
• B) Enthalpy
• C) Humidity ratio
• D) Relative humidity

Q8: 8. A cooling coil in an air conditioning system operates at 12°C dry-bulb temperature and 50% relative humidity. What is the enthalpy of the air passing through the coil?

• A) 30 kJ/kg
• B) 40 kJ/kg
• C) 50 kJ/kg
• D) 60 kJ/kg

Q9: 9. How is the specific humidity calculated using a psychrometric chart?

• A) By finding the intersection of dry-bulb temperature and humidity ratio lines
• B) By reading the enthalpy value at a specific point on the chart
• C) By determining the difference between wet-bulb and dry-bulb temperatures
• D) By locating the saturation curve on the chart

Q10: 10. In a refrigeration system, what role does the psychrometric chart play in determining the required cooling capacity?

• A) Estimating compressor power
• B) Sizing the evaporator and condenser
• C) Calculating refrigerant charge
• D) Setting the room temperature

Q11: 11. A heat exchanger in a refrigeration unit operates at a dry-bulb temperature of 5°C and a wet-bulb temperature of 3.5°C. What is the relative humidity of the air entering the heat exchanger?

• A) 40%
• B) 50%
• C) 60%
• D) 70%

Q12: 12. How can the psychrometric chart help in analyzing the performance of a cooling tower in an HVAC system?

• A) By determining the specific humidity of the air leaving the tower
• B) By calculating the wet-bulb temperature drop across the tower
• C) By estimating the compressor efficiency
• D) By monitoring the condenser pressure

Q13: 13. In a scenario where the dry-bulb temperature is 30°C and the wet-bulb temperature is 25°C, what is the specific volume of the air?

• A) 0.85 m^3/kg
• B) 0.90 m^3/kg
• C) 0.95 m^3/kg
• D) 1.00 m^3/kg

Q14: 14. How is the relative humidity of air calculated using the psychrometric chart?

• A) By reading the humidity ratio at a specific point on the chart
• B) By locating the intersection of dry-bulb temperature and wet-bulb temperature lines
• C) By determining the difference between dry-bulb and wet-bulb temperatures
• D) By comparing the specific volume to the saturation curve

Q15: 15. A refrigeration system is designed to maintain a room at 22°C dry-bulb temperature and 50% relative humidity. What is the dew point temperature in the room?

• A) 12°C
• B) 14°C
• C) 16°C
• D) 18°C

Q16: 16. Why is it important to consider the psychrometric properties of air in the design of HVAC systems?

• A) To ensure proper indoor air quality
• B) To regulate the room temperature effectively
• C) To prevent mold growth
• D) All of the above

Q17: 17. In a refrigeration cycle, what role does the psychrometric chart play in determining the evaporator temperature?

• A) Estimating the compressor efficiency
• B) Selecting the refrigerant type
• C) Sizing the expansion valve
• D) Calculating the required cooling load

Q18: 18. A commercial freezer operates at a dry-bulb temperature of -18°C and a relative humidity of 40%. What is the specific humidity of the air inside the freezer?

• A) 0.002 kg/kg
• B) 0.004 kg/kg
• C) 0.006 kg/kg
• D) 0.008 kg/kg

Q19: 19. How does the psychrometric chart help in determining the energy efficiency of an air conditioning system?

• A) By calculating the heat transfer rate in the evaporator and condenser
• B) By analyzing the compressor work input
• C) By optimizing the refrigerant flow rate
• D) By monitoring the indoor air temperature

Q20: 20. A cooling tower in an industrial plant cools water from 35°C to 25°C using ambient air at a dry-bulb temperature of 28°C and a wet-bulb temperature of 22°C. What is the effectiveness of the cooling tower?

• A) 50%
• B) 60%
• C) 70%
• D) 80%

Q21: 21. How can the psychrometric chart assist in troubleshooting issues with an air conditioning system that is not cooling effectively?

• A) By adjusting the thermostat setting
• B) By checking for refrigerant leaks
• C) By analyzing the air flow rate
• D) By identifying the specific enthalpy of the air entering the evaporator

Q22: 22. A refrigeration unit is designed to maintain a constant humidity ratio of 0.008 kg/kg at a dry-bulb temperature of 10°C. What is the specific volume of the air in the system?

• A) 0.75 m^3/kg
• B) 0.80 m^3/kg
• C) 0.85 m^3/kg
• D) 0.90 m^3/kg

Q23: 23. What impact does the psychrometric chart have on the selection of an appropriate cooling coil for an air conditioning system?

• A) Determining the required compressor capacity
• B) Sizing the coil for efficient heat transfer
• C) Setting the room temperature
• D) Adjusting the refrigerant flow rate

Q24: 24. In a scenario where the wet-bulb temperature is 15°C and the dry-bulb temperature is 25°C, what is the relative humidity of the air?

• A) 40%
• B) 50%
• C) 60%
• D) 70%

Q25: 25. How can the psychrometric chart be used to optimize the performance of a dehumidification system in a commercial building?

• A) By adjusting the air flow rate
• B) By monitoring the cooling coil temperature
• C) By controlling the relative humidity setpoint
• D) By increasing the room temperature