Johnson Resource Guide Refrigeration for HVACR Technicians

1. A fundamental law of thermodynamics states that heat always moves from

Warmer to cooler

2. To say that heat moves by conduction is to say that

A. Heat moves through a solid

3. To say that heat moves by convection is to say that

A. Heat moves through a liquid

4. To say that heat moves by radiation is to say that

A. Heat moves through the air

5. When a substance boils it

A. Absorbs heat

6. When a substance condenses it

A.Rejects heat Changing from a vapor to a liquid

7. The process of change-of-state in a refrigeration system takes place in

A. The condenser

8. The process of a creating a pressure drop in a refrigeration system occurs in

A. The metering device

9. Of the popular types of compressors used in vapor compression refrigeration systems

the least efficient is, A. The piston compressor

10. In the event that liquid droplets enter the suction side of a rotary compressor

A. A condition known as hydraulic skip will occur

11. Large refrigeration systems typically use what type of water-cooled condenser

A. Shell and Tube

12. When a refrigeration system employing an evaporative condenser is operating in cooler weather

A. The water pump may be turned off

13. When a wastewater system is employed in water-cooled condensers approximately ____ gallons of water per minute for each ton of refrigeration system capacity is circulated

A. 1.5 gallons per minute

14. When a re-circulating system is employed in water-cooled condensers approximately ____ to ____ gallons of water per minute for each ton of refrigeration system capacity is circulated.

A. 3 to 5 gallons

15. The temperature difference between the water entering and the water leaving a wastewater system is generally between:

A. 15 to 20 degrees

16. When considering the idea of refrigerant temperature the normal condensing temperature of the refrigerant in a re-circulating water-cooled system is usually ____ degrees higher than the temperature of the condenser outlet water.

A. 10 degrees

17. Two types of fixed bore metering devices are

A. Capillary Tube and Restrictor

18. From a fundamental perspective the TEV works on three pressures. They are

A. Bulb, Spring and Evaporator

19. The type of heat that brings about a change in state but not a change in temperature is

A. Latent heat

20. The purpose of a heat exchanger is to:

A. Prevent droplets of liquid in the vapor stream and Subcool the liquid to prevent flash gas in the liquid line

21. An accumulator in a refrigeration system is a storage tank for refrigerant on the

A. Suction line

22. A sight glass in a refrigeration system is typically installed

A. Between the receiver and the metering device

23. An oil pressure safety switch on a refrigeration system monitors the difference in pressure between

A. The compressor suction and oil pump discharge

24. The valve that protects the compressor in the event of a hot pull-down is

A. A CPR valve

25. Which component prevents the migration of liquid refrigerant into the compressor crankcase?

A. Crankcase Heater