thermal energy is ejected to the surroundings. Like an evaporator, a condenser is also made of
a series of tubes with good thermal conductivity. As the refrigerant flows through the condenser,
more and more heat is removed (or transferred to the surroundings); consequently, the refrig-
erant changes phase from gas to liquid and it leaves the condenser coil in liquid phase. In the
older version of a household refrigerator, the condenser is the series of black tubes located on
the back of the refrigerator. In an air-conditioning unit, the condenser is located outside the
building in a housing unit that also contains the compressor and a fan that forces air over the
condenser. After leaving the condenser, the liquid refrigerant flows through an expansion
valve or a long capillary tube, which makes the refrigerant expand. The expansion is followed
by a drop in the refrigerant’s temperature and pressure. The refrigerant leaves the expansion
valve or the capillary tube and flows into the evaporator to complete the cycle shown in
Figure 13.11.
Another point worth mentioning is that as the warm air flows over the evaporator section
of an air-conditioning unit, and as the air cools, the moisture (the water vapor) in the air con-
denses on the outside of the evaporator coil. The condensation forming on the outside of the
evaporator is eventually drained. Thus, the evaporator acts as a dehumidification device as well.13.5 Efficiency 391
Evaporator
Condenser
■Figure 13.12 The typical locations of the evaporator and the condenser in a household refrigerator.
Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).圀圀圀⸀夀䄀娀䐀䄀一倀刀䔀匀匀⸀䌀伀䴀圀圀圀⸀夀䄀娀䐀䄀一倀刀䔀匀匀⸀䌀伀䴀