AIR-CONDITIONING AIR-CONDITIONING EDUCATION

Air Conditioning

1. z
AIR
CONDITIONING

2. Air conditioners employ the same
operating principles and basic components
as your home refrigerator. Refrigerators use
energy (usually electricity) to transfer heat
from the cool interior of the refrigerator to
the relatively warm surroundings of your
home; likewise, an air conditioner uses
energy to transfer heat from the interior of
your home to the relatively warm outside
environment.

3. An air conditioner cools your home with a cold
indoor coil called the evaporator. The
condenser, a hot outdoor coil, releases the
collected heat outside. The evaporator and
condenser coils are serpentine tubing
surrounded by aluminum fins. This tubing is
usually made of copper. A pump, called the
compressor, moves a heat transfer fluid (or
refrigerant) between the evaporator and the
condenser. The pump forces the refrigerant
through the circuit of tubing and fins in the
coils.

4. The liquid refrigerant evaporates in the
indoor evaporator coil, pulling heat out of
indoor air and cooling your home. The hot
refrigerant gas is pumped outdoors into the
condenser where it reverts back to a liquid,
giving up its heat to the outside air flowing
over the condenser's metal tubing and fins.

5. Throughout the second half of the 20th
century, nearly all air conditioners used
chlorofluorocarbons (CFCs) as their
refrigerant, but because these chemicals are
damaging to Earth's ozone layer, CFC
production stopped in the United States in
1995. Nearly all air conditioning systems
now use halogenated chlorofluorocarbons
(HCFCs) as a refrigerant.

6. The latest HCFC, HCFC-22 (also called R-
22), began to be phased out in 2010 and
stopped entirely in 2020. However, HCFC-
22 is expected to be available for many
years as it is removed and reused from old
systems that are taken out of service. As
these refrigerants are phased out, ozone-
safe hydrofluorocarbons (HFCs) are
expected to dominate the market, as well as
alternative refrigerants such as ammonia.

8. Air conditioners are called "split-systems"
because there is an outdoor unit (the
condenser) and an indoor unit (the
evaporator).These two systems work
together to accomplish the task of cooling
an interior space while also dehumidifying it.
This dehumidification happens as warm air
from inside passes over the cold evaporator,
where the warm air condenses and loses
moisture, just like warm air does on a cold
glass of lemonade.

11. A heat pump uses electricity to provide both
heating and cooling to a building. These
appliances are efficient at transferring heat
from one place to another, depending on
where it’s needed.
​In the winter, a heat pump provides heating
by extracting heat from outside a building
and moving it inside. In the summer, it can
provide cooling by moving heat from indoors
to the outside.

13. A heat pump uses the same technology as
an air conditioner, which cools your home
using a refrigerant. The only major
difference between an air-conditioner and a
heat pump is that a heat pump has a
reversing valve, which allows it to also heat
your home.
In heating mode, a heat pump works like an
air conditioner in reverse; instead of keeping
your home cool, it uses the refrigerant to
warm your home.

14. There are different types of heat pumps: air-
source and ground-source.
An air-source heat pump takes heat from
the air and boosts it to a higher temperature.
A ground-source heat pump system
harnesses natural heat from underground by
pumping liquid through it in pipes. The heat
pump then increases the temperature and
the heat is used to provide heating or hot
water.

15. Heat pumps can also be paired with fossil
fuel gas furnaces; these systems are often
referred to as hybrid heat pumps.
A hybrid heat pump system, also called a
dual energy system, integrates a heat pump
(air source or ground source) with your
traditional gas furnace or boiler heating
system –and potentially even hydrogen
boiler in the future.

16. A hybrid heating system monitors the
temperature outside and automatically
chooses the most energy efficient option to
keep your home consistently warm and your
water hot.