Removing undesirable heat from one item, substance, or area and transferring it to another is known as refrigeration, sometimes known as chilling. The temperature can be lowered by removing heat, which can be done using ice, snow, cooled water, or mechanical refrigeration.

1. Refrigeration
May 8, 2023admin
Removing undesirable heat from one item, substance, or area and
transferring it to another is known as refrigeration, sometimes known as
chilling. The temperature can be lowered by removing heat, which can be
done using ice, snow, cooled water, or mechanical refrigeration.
In order to decrease the temperature of the area or material and then maintain
that lower temperature, refrigeration is the act of taking heat from an enclosed
space or from a substance and discarding it elsewhere. Any natural or artificial
process that dissipates heat is referred to as cooling. Cryogenics is the name
given to the branch of science that deals with creating extremely low
temperatures artificially. Since cold is the absence of heat, lowering a
temperature requires “removing heat” rather than “adding cold.” When heat is
removed, work must be done in some way in order to comply with the Second
Law of Thermodynamics. Although usually done mechanically, this task can
alternatively be accomplished using a laser, magnets, or other technologies.
Historical applications
Ice harvesting
Ice has been used to chill food from the beginning of time in order to preserve
it. Throughout the millennia, the majority of ancient societies, including the
Chinese, Hebrews, Greeks, Romans, and Persians, engaged in a seasonal
practice of gathering snow and ice. Straw or other insulating materials were
used to line caverns or dugouts where ice and snow were kept. Ice was kept
in holes known as yakhchals by the Persians. Foods might be kept fresh
throughout the warm months by rationing ice. Icehouses were still in use in
the twentieth century as a result of this practice’s success over the ages.

2. One of the early steps towards artificial refrigeration was made in the
sixteenth century with the discovery of chemical refrigeration. When added to
water, sodium nitrate or potassium nitrate causes the water’s temperature to
drop, creating a form of refrigeration bath for chilling items. Such a remedy
was applied to cool wine in Italy. American ice harvesting developed into a
significant industry in the first part of the nineteenth century. The “Ice King,” a
New Englander named Frederic Tudor, worked on creating superior insulating
materials for long-distance ice shipping, particularly to tropical regions.
First refrigeration systems
William Cullen presented the first known technique for artificial refrigeration in
Scotland’s University of Glasgow in 1756. When Cullen used a pump to
partially hoover a container of diethyl ether, the substance boiled and
absorbed heat from the atmosphere around it. Even though the experiment
produced a little amount of ice, it had no immediate use.
Oliver Evans, a pioneering American inventor, created a vapor-compression
refrigeration cycle in 1805 as an alternative to chemical solutions or
flammable liquids like ethyl ether. Ammonia and other gases were liquefied in
1820 by British scientist Michael Faraday using high pressures and low
temperatures.
In 1834, an American named Jacob Perkins who resided in Great Britain was
granted the first patent for a vapor-compression refrigeration device. The
prototype system that Perkins created really functioned, despite its
commercial failure. John Gorrie, an American physician, created the first
method of chilling water to create ice in 1842. He also came up with the
concept of air conditioning, which involves employing a refrigeration system to

3. chill the air for comfort in homes and hospitals. His technology compressed
air, partially cooled the hot compressed air by adding water, and then allowed
it to expand while performing some of the labor necessary to power the air
compressor.
According to his invention, which was issued by the U.S. invention Office in
1851, the isentropic expansion lowered the air’s temperature to the point
where it could either pass “through a pipe for effecting refrigeration otherwise”
or freeze water and make ice. Gorrie created a functional prototype, but his
system was not successful in the marketplace.
In 1848, Alexander Twining started experimenting with vapor-compression
refrigeration, and in 1850 and 1853, he was granted patents. By 1856, he is
credited with starting commercial refrigeration in the US. In the middle of the
1870s, Australian, Argentinean, and American shipping companies
experimented with refrigerated shipping. In 1882, William Solti Davidson
installed a compression refrigeration unit on the New Zealand ship Dunedin,
which resulted in a boom in meat and dairy exports to Australasia and South
America. American Civil War balloonist Thaddeus Lowe has conducted
several studies on the characteristics of gases. High-volume hydrogen gas
manufacturing was one of his key businesses. He also has a number of ice-
making machine patents. The “Compression Ice Machine” he created would
transform the cold storage sector. He and other partners bought an old
steamer in 1869, installed one of Lowe’s refrigeration units onto it, and started
transporting fresh produce from Galveston, Texas, back to New York, as well
as fresh meat from the Gulf Coast. The venture was an expensive failure due
to Lowe’s ignorance of shipping, and it took a while for people to adjust to the
concept of being able to eat meat.
Widespread commercial use
Although some still used gathered ice, breweries were by far the biggest
consumers of commercial refrigeration systems by the 1870s. Even though
the ice harvesting business had expanded significantly by the turn of the 20th
century, sewage and pollution had started to contaminate natural ice, which
was a concern in the urban areas. Breweries eventually started to complain
about contaminated ice. This increased demand for more contemporary
refrigeration and ice-making equipment that is suitable for consumers.
German inventor Carl von Linde developed a large-scale method for creating
liquid oxygen and then liquid air for use in secure home freezers in 1895.

4. In the 1840s, chilled railway trains were first used in the United States to carry
dairy goods over short distances. A refrigerated vehicle with ice tanks at either
end and ventilation flaps close to the floor that would provide a gravity draught
of cold air through the car was invented in 1867 by J.B. Sutherland of Detroit,
Michigan. Chicago’s meat packing facilities had switched to ammonia-cycle
commercial refrigeration by 1900. By 1914, artificial refrigeration was
employed practically everywhere. The largest meat packers, Armor, Swift, and
Wilson, had bought the priciest models and put them on rail carriages, in
branch homes, and in storage facilities in the most outlying distribution
locations.
Refrigeration units weren’t made to be installed on tractor-trailer rigs (trucks or
lorries) until the middle of the 20th century. Perishable products, including
frozen meals, fresh produce, and temperature-sensitive chemicals, are
transported in refrigerators. The majority of contemporary freezers operate in
the -40 to +20 °C range and may hold a maximum payload of around 24 000
kg gross weight (in Europe).
Home and consumer use
Safer refrigerators for residential and consumer use became feasible with the
development of synthetic refrigeration systems, which are primarily based on
the chemical chlorofluorocarbon (CFC). These CFC refrigerants, as well as
subsequent hydrochlorofluorocarbon (HCFC) and hydrofluorocarbon (HFC),
are referred to as “Freon,” a trademark of the DuPont Corporation. These
refrigerants, which were created in the late 1920s, were thought to be safer
than the routinely employed refrigerants of the time, such as methyl formate,
ammonia, methyl chloride, and sulphur dioxide. The goal was to supply

5. residential refrigeration equipment while protecting the tenants’ life. These
CFC refrigerants provided the solution.
The Montreal Protocol
Because it harms the ozone layer, CFC-based refrigerant has been prohibited
since 1989 thanks to the Montreal Protocol. In Montreal, Quebec, Canada, in
September 1987, the majority of the CFC-producing and -consuming
countries approved the Montreal Protocol. Greenpeace opposed the
ratification since the Montreal Protocol authorized the use of HFC
refrigeration, which does not deplete the ozone layer but nonetheless
contributes significantly to global warming. With help from Greenpeace, duke
Shorenstein (Germany) created a propane-based CFC and an HFC-free
refrigerator in 1992 while looking for a replacement for home use refrigeration.
In August 1988, the Clean Air Act became law, implementing the Montreal
Protocol’s principles in the US. In 1990, the Clean Air Act underwent more
changes. This was a direct outcome of a scientific research published in June
1974 by Rowland-Molina[6], which described how the ozone layer was
negatively impacted by chlorine in CFC and HCFC refrigerants. As a result of
this analysis, the FDA and EPA decided to outlaw CFCs as a propellant in
1978 (at the time, aerosol can propellant accounted for 50% of CFC
consumption).
 Refrigerant recovery from all car air conditioning systems was
mandated by the EPA in January 1992 as part of system maintenance.
 The EPA outlawed the venting of CFC and HCFC refrigerants in July
1992.
 The EPA mandated that significant leaks in refrigeration systems be
repaired within 30 days in June 1993. A major leak was defined as a
leak rate that, if it continued for an entire year, would equal 35% of the
system’s total refrigerant charge (for industrial and commercial
refrigerant systems) or 15% of the system’s total refrigerant charge (for
all other large refrigerant systems).
 The EPA implemented the Safe Disposal Requirements in July 1993,
mandating that all refrigerant systems be evacuated before being retired
or disposed of.
 The EPA introduced rules for refrigerant reclamation in August 1993.
The American Refrigeration Institute (ARI) standard 700-1993 (formerly
ARI standard 700-1995) standards for refrigerant purity must be
processed and tested before a refrigerant can change ownership.

6.  The EPA mandated that ARI 740-1993 criteria be met by all refrigerant
recovery equipment in November 1993.
 The EPA also put restrictions on releasing HFC refrigerants in
November 1995. These have a 0% ODP (ozone depletion potential)
since they don’t contain chlorine that might harm the ozone layer, but
they nevertheless have a significant potential for global warming.
 The importing and manufacture of CFC refrigerants in the United States
were outlawed in December 1995.
HCFC refrigerant import and manufacture are now scheduled to end in 2030,
yet this is most likely going to happen sooner.
Current applications of refrigeration
The air conditioning of private residences and public buildings, as well as the
refrigeration of goods in homes, restaurants, and big storage warehouses, are
perhaps the two most common modern uses of refrigeration. We can now add
fresh salads to our meals throughout the year and securely preserve fish and
meats for a long time thanks to the refrigerators we use in our homes to store
fruits and vegetables.
Refrigeration has a wide range of applications in industry and commerce.
Gases like oxygen, nitrogen, propane, and methane, for instance, are
liquefied using refrigeration. It is used to condense water vapour from
compressed air to lower its moisture content in compressed air purification.
Refrigeration is used in chemical, petrochemical, and oil refineries to keep
specific processes running at the requisite low temperatures (for instance, the
alkylation of butenes and butane to create a high octane petrol component).
Steel and cutlery are tempered in refrigerators by metalworkers. Refrigeration
is required for carrying items that need to be kept at a specific temperature via
trucks, railroads, aircraft, and seagoing vessels.
It was only recently realised that eggs required to be chilled throughout
shipment rather than waiting to be chilled after arrival at the grocery store,
despite the fact that dairy products require refrigeration continually. Before
being marketed, all meats, poultry, and fish must be maintained in climate-
controlled conditions. Fruits and vegetables are kept fresher for longer when
they are refrigerated. The growth of the sushi and sashimi business in Japan
was one of the most significant applications of refrigeration. Before
refrigeration was discovered, hepatitis A and other illnesses caused a
tremendous deal of morbidity and mortality among sushi lovers. However, due
to a lack of research and healthcare access in rural Japan, the hazards of

7. unrefrigerated sashimi were not made public for decades. Midway through the
20th century, the Kyoto-based Zojirushi business developed advancements in
refrigerator design that made them more affordable and available to
restaurant owners and the general public.
Reference
 https://www.ashrae.org/technical-resources/refrigeration
 https://www.britannica.com/technology/refrigeration
 https://berg-group.com/engineered-solutions/the-science-behind-
refrigeration/#:~:text=Refrigeration%2C%20or%20cooling%20process%
2C%20is,chilled%20water%20or%20mechanical%20refrigeration.