The Refrigeration Process In Your Refrigerator:
refrigerator found in the common kitchen uses a cycle that is very
similar to the previously described, generic cycle.
the original home refrigerator, the refrigerant used was essentially
pure ammonia. Ammonia is a fairly volatile substance that has been
found to be toxic to humans, and since then has been replaced.
Chlorofluorocarbons (CFC's) were created to reduce danger levels
to humans. CFC's were later determined to be harmful to the environment,
so other substitutes were created in the early 1990's. Freon is
the common refrigerant found in home refrigerators today. However,
for this example, the cycle will be explained using the original
refrigerant of ammonia.
begin the cycle, the ammonia is compressed. The compress gas heats
up (the orange region) and the heat is released to the atmosphere
through the heat-exchanging pipes or coils often found on the back
of the refrigerator.
of How Refrigerators Work)
The ammonia then begins to condense as it heads towards the expansion
valve (the red to purple region). The once high-pressure ammonia
then heads through the expansion value, sending the ammonia into
a low-pressure zone. This pressure change causes the ammonia to
boil and vaporize (the light blue region). This causes the cooling
inside the refrigerator. After the ammonia travels through the network
of coils, it travels back through the compressor and begins the
process again (How Refrigerators Work 5).
for Scientists and Engineers)
above picture is of the back of the average home refrigerator. It
does an excellent job of showing the heat exchanging pipes used
for external cooling, as well as the compressor located at the bottom.
Refrigeration Process In Other Types of Refrigerators:
are several other types of refrigerators on the market today. Some
refrigerators are powered by propane, kerosene, or gas. It should
be noted that the processes these machines undertake are similar
to that of the above "standard" refrigerator, but not
identical. Some notable component differences that the propane fridge
posses are as follows (How
Refrigerators Work 6):
(or boiler system)
is a diagram of how the gas refrigeration system works.
Propane Refrigeration Units.)
pieces allow for the cooling process to take place without electricity.
Since electricity has been removed from the equation, another substitute
is required to power this system. This substitute is propane.
allows for the application of heat to the ammonia generator. This
heating causes ammonia to reach its boiling point. The boiling mixture
then travels through a separator, where water and ammonia are partitioned.
The ammonia is the important portion of the mixture, as it proceeds
from this step up towards the condenser. The condenser allows the
ammonia to cool at a rapid rate, allowing the boiling ammonia to
liquefy. Once the ammonia has changed states it heads towards the
evaporator, where it is mixed with hydrogen gas. This mixing allows
for evaporation, which produces the cold temperatures that can be
found in the fridge. What is left of the ammonia and hydrogen gas
flows into the absorber. The ammonia and water mix to form a liquid
state, and the hydrogen gas travels back up into the evaporator.
Once this has been competed, the cycle can begin again (Propane
now examine other types of cooling methods, such as peltier coolers.