Copyright Goodheart-Willcox Co., Inc. 102 Chapter Review Summary • Heat transfer is accomplished in refrigeration systems by refrigerant changing phase between vapor and liquid. As a refrigerant evaporates, it absorbs heat. As refrigerant condenses, it expels heat. Heat always flows from hot to less hot. • The four processes that make up a compression refrigeration system are compressing, condensing, metering, and evaporating. A compression refrigeration system uses mechanical energy to drive the refrigeration process. • A compressor raises the pressure and heat content of a refrigerant as it pumps the refrigerant into the high side of the system. • Condensation of refrigerant takes place in a condenser. This process releases heat and changes the phase of the refrigerant from vapor to liquid. • A liquid line is a refrigerant passage from a condenser or liquid receiver and to a metering device. A filter-drier in the liquid line removes moisture and contaminants from high-side refrigerant. • A metering device restricts the passage of refrigerant to lower its pressure. A metering device divides the high side of the system from the low side. • Evaporation of refrigerant takes place in an evaporator. As liquid refrigerant absorbs heat, it changes into a vapor. • A suction line is a refrigerant passage from an evaporator to a compressor. It may contain an accumulator and a filter-drier. • By allowing only vapor refrigerant to flow through a suction line, accumulators protect compressors from damage that would be caused by pumping liquid refrigerant. Review Questions Answer the following questions using the information in this chapter. 1. _____ refrigerant is like a dry sponge that has the ability to soak up a lot of water. A. Low-pressure liquid B. Low-pressure vapor C. High-pressure liquid D. High-pressure vapor 2. _____ refrigerant is like a soaking wet sponge that cannot absorb more water. A. Low-pressure liquid B. Low-pressure vapor C. High-pressure liquid D. High-pressure vapor 3. From the metering device through the evaporator to the compressor is the _____ side of the system. A. low B. high C. condensing D. heat-rejecting 4. From the compressor exhaust through the condenser and liquid line to the metering device is the _____ side of the system. A. low B. high C. evaporative D. suction 5. Using suction, a compressor draws in refrigerant by creating _____ in the evaporator. A. low pressure B. high pressure C. low temperatures D. high temperatures 6. Using the process of compression, a compressor increases refrigerant _____. A. pressure and volume B. temperature and volume C. volume and heat content D. pressure and heat content 7. Commonly used in different HVACR applications, _____ compressors use a back- and-forth or up-and-down motion. A. rotary B. scrolling C. reciprocating D. centrifugal 8. A heat-exchanging device designed to expel or reject heat is a(n) _____. A. accumulator B. evaporator C. liquid receiver D. condenser 9. A condenser that uses a fan to remove heat more quickly is called a _____ condenser. A. static B. forced-air C. natural-convection D. water-cooled