
A standard operation heat engine (left) operated by a forward Carnot cycle, shown adjacent to a refrigerator (right), a heat engine operated by a reverse Carnot cycle: the idea being that by removing heat from a low temperature region or source (say the volume of the region inside of a freezer), by contact with a working substance (shown as the circle, above), being typically a gas, such as ammonia or carbon dioxide, which is forced to compression (work done on the substance) by an external energy or work input (say from the power company), and then passing this removed heat to a third body, i.e. the heat sink or body of air surrounding the refrigerator in the kitchen. [1]

A standard operation heat engine (left) operated by a forward Carnot cycle, shown adjacent to a refrigerator (right), a heat engine operated by a reverse Carnot cycle: the idea being that by removing heat from a low temperature region or source (say the volume of the region inside of a freezer), by contact with a working substance (shown as the circle, above), being typically a gas, such as ammonia or carbon dioxide, which is forced to compression (work done on the substance) by an external energy or work input (say from the power company), and then passing this removed heat to a third body, i.e. the heat sink or body of air surrounding the refrigerator in the kitchen. [1]

In engineering, a refrigerator is a heat engine that is run in reverse, the cycle of which operates such that work is done on the working substance so as to resultantly cause heat to flow from a cold body to a hot body.

History
In 1748, Scottish chemist William Cullen was the first to make artificial refrigeration, using the phenomenon of cold being produced by evaporating liquids (nitrous aether), plus a vacuum. Cullen's device has come to be known as the Cullen refrigerator.

In 1805, American inventor Oliver Evans laid the foundation for the continuous-cycle vapor-compression refrigerator when he conceived a method for recycling vaporized refrigerant. Evans design (see diagram below) operated such that after removing heat from the surrounding environment, vaporized refrigerant would move through a compressor, and then a condenser, where it would revert back into a liquid form and begin the process again. Evans, curiously similar to Denis Papin and his cyclical heat engine design, however, never saw his design through into actuality. [7]

In 1824, French physicist Sadi Carnot introduced the Carnot cycle, using the labels of the hot body as the "furnace" and the cold body as the "refrigerator", in the discussion of which he laid out the basic operation of the refrigerator as a reverse-operated heat engine.

In 1834, an associate of Evans, American-born English inventor Jacob Perkins built on Evans’ ideas to construct a cyclic vapor-compression machine, using ether as a refrigerant. Perkins refrigeration machine was the first full-scale machine to contain a compressor, a condenser, and expansion valve, and an evaporator—the basic parts to a modern mechanical compression refrigeration system. Perkins, however, never developed his machine for commercial use. [7]

In 1870, German mechanical engineer Carl Linde used the science of thermodynamics to design a system to refrigerate beer, and was said to have been the first to use this scientific approach. [2]


A vapor-compression refrigerator, similar to the one made in 1834 by American-born English inventor Jacob Perkins. [7]

A vapor-compression refrigerator, similar to the one made in 1834 by American-born English inventor Jacob Perkins. [7]

Local entropy decrease
The refrigerator model is often incorrectly invoked to explain or account for the apparent order of evolved entities, e.g. humans, against the apparent tendency to disorder interpretation of entropy, such that humans, animals, and plants are seen as a type of “local entropy decrease”, something to the effect that the sun does work to decrease entropy, a low entropy structure assumed to be synonymous with an ordered animate thing, such as a human.

Historically, the "local entropy" model of life seems to have been first introduced in the 1947 book Time and Thermodynamics by Belgian-born English thermodynamicist Alfred Ubbelohde, in which he first gives a derivation that the chilled space inside of a refrigerator is a region of "local decrease in entropy" and then goes on to argue that this this is analogous to life. [3]


A 1851 version of American physician John Gorrie's ice machine, invented in 1841, which he used to cool the rooms of patients suffering from fever in his hospital. [6]

A 1851 version of American physician John Gorrie's ice machine, invented in 1841, which he used to cool the rooms of patients suffering from fever in his hospital. [6]

A 1992 version of this humans having a low entropy derived by a sort of refrigerator operation logic is given by Polish-born Canadian physicist Marek Roland: [4]

“During the production of clothing, cars, and chemical compounds, etc., the entropy of the system is decreased because the components become organized. This is done, however, at the expense of the manufacturing system (including people) whose entropy [human entropy] will increase during this process [similar to how] a refrigerator [makes ice] at the expense of increased entropy of the environment.”

In 2000, Indian science philosopher Srdan Lelas employed this argument as such: [5]

“The living organism seems to be a macroscopic system which in part of its behavior approaches to that purely mechanical (as contrasted with thermodynamical) conduct to which all systems tend, as the temperature approaches the absolute zero and the molecular disorder is removed. The challenge of being a living being is much more demanding than the challenge of being a refrigerator. What Schrodinger is pointing to here is the bearing of the entropy principle, or the second law of thermodynamics, on the characterization of living beings.”


A local entropy decrease interpretation of a refrigerator.

A local entropy decrease interpretation of a refrigerator.

Although its is not at all correct what Lelas is saying here, being that Gibbs free energy is the quantity of interest when it comes to explaining human states of order or disorder, the notion of a human as a refrigerator is, nevertheless, exemplified.

References
1. Dincer, Ibrahim and Kanoglu, Mehmet. (2010). Refrigeration Systems and Applications (pgs. 107). Wiley.
2. (a) Clark, Robert P. (2001). Global Life Systems: Population, Food, and Disease in the Process of Globalization (199). Rowman & Littlefield.
(b) Zeuner, Gustav. (1907). Technical Thermodynamics, Volume 2 (pgs. 462-63). D. Van Nostrand Co.
3. Ubbelohde, Alfred René. (1947). Time and Thermodynamics, (section “Experimental Aspects of the Relation between Thermodynamics and Life”, pgs. 100-05). Oxford University Press.
4. (a) Roland-Mieszkowski, Marek. (c.1992). “Life on Earth - Flow of Energy and Entropy.” (PDF), Digital Recordings.
(b) Digital Recordings Publications (Special Interest Papers) – Digital-Recordings.com.
5. Lelas, Srdan. (2002). Science and Modernity: Toward an Integral theory of Science (ch. 5: Life, pgs. 64-77, esp. pg. 70). Springer (2000, first ed.?).
6. (a) Diagram of John Gorrie's Ice Machine. From U.S. Patent 8080, May 6, 1851.
(b) John Gorrie – Wikipedia.
(c) Becker, Raymond B. (1972). John Gorrie, M.D.: Father of Air Conditioning and Mechanical Refrigeration. Carlton Press.
7. Hempstead, Colin and Worthington, William E. (2005). Encyclopedia of 20th-century Technology, Volume 2 (pgs. 672-). Taylor and Francis.

Further reading
● Goldstein, Martin and Goldstein, Inge F. (1993). The Refrigerator and the Universe: Understanding the Laws of Energy. Harvard University Press.
● Flynn, Thomas M. (2005). Cryogenic Engineering. Marcel Dekker.

External links
● Refrigerator – Wikipedia.
● Refrigeration – Wikipedia.
● Heat pump and the refrigeration cycle – Wikipedia.
● Vapor-compression refrigeration – Wikipedia.