The refrigerator was one of the most innovative and important inventions of the twentieth century. Initially there were two different types of refrigerators competing for the market: the gas refrigerator and the electric refrigerator. This site will focus on the gas refrigerator: the mechanism behind it and the reasons for its failure. Gas-type household refrigerators act on the absorption principle. Absorb means to take up or in by chemical or molecular action. Since a refrigerant (such as Freon, ammonia or Carbon Dioxide) is ultimately absorbed at one point in the system, the gas refrigerator is known as an absorption refrigerator (1).

In gas powered refrigeration, the process begins with an apparatus known as a generator. The generator is basically a metal tank with one section having a series of coils containing steam. The steam is created via a gas flame. Strong liquid (ammonia mixed with water) flows over the coils and the heat from the steam causes it to boil. As a result of the boiling, the strong liquid gives off ammonia vapor which exits the generator (2). This ammonia gas leaving the generator contains a small percentage of water and is somewhat warm. The gas enters the rectifier which is an amalgam of a heat exchanger and condenser created to purify the gas by taking away the heat and water. The heat from the gas is removed by liquid flowing though the rectifier. The cooling of the gas is what removes the water vapor. The water vapor condenses and drips back into the generator (3). The ammonia gas, however, proceeds to the condenser. It is here that the ammonia vapor is reduced to a denser form - liquid. The condenser consists of a ladder of tubes parallel to one another. Water flows downward over the outside of the tubes, taking heat from the warm gas flowing through them. The temperature decreases causing the ammonia gas to change phases. At the bottom of the condenser, liquid ammonia flows out (4). This anhydrous ammonia then passes though a brine cooler. Brine is simply the salt, of any substance, dissolved in water. The ammonia chills the brine and the brine then chills the unit (5). The ammonia then passes through the evaporator where it returns to gaseous form. The ammonia then proceeds to the absorber. Here, the evaporated ammonia is dissolved into water. After the ammonia is absorbed, the liquid is now strong and the cycle can begin again. A pump draws off the strong liquid, and discharges it to the generator where the process starts over (6). To sum up, a gas flame initiates a series of phase change reactions involving a refrigerant (ammonia) culminating in the cooling of a brine and the refrigeration unit.

Although the gas model refrigerator was technologically sound, it would prove to be a failure in the market. Its better funded and advertised cousin - the electric model refrigerator - would triumph in sales. The companies behind the gas refrigerators had neither the technical or financial assets that the companies behind the electric refrigerators had. The gas refrigerator was practically silent. It contained few moving parts which decreased the likelihood of malfunction. Its operating cost was quite insubstantial particularly in areas where electricity was more expensive than gas (7). With only some flaws, and the aforementioned advantages, it is hard to believe that the gas refrigerator wound up being a failure. However, those flaws proved to be troublesome and combined with competing against a financial juggernaut proved to be fatal. One problem with gas refrigerators was the use of ammonia as the refrigerant (8). Ammonia will kill or cause serious injuries even in concentrations as infinitesimal as one half of one percent by volume. Ammonia can sear the lungs as well as burn the skin (9). It is understandable why people were afraid to use ammonia to store their food products. Though problems such as the fear of ammonia contributed to the demise of the gas refrigerator, money was the ultimate cause of its failure. Gas refrigerator manufacturers lacked the massive sums of money characteristic of the electric refrigerator companies. In the same year that the electric refrigerator company, Kelvinator, had a budget of one million dollars, the Common Sense Company, a manufacturer of gas refrigerators, worked with thirty thousand dollars (10). Kelvinator had a budget that was 33 times more than that of the Common Sense Company. Such an economic advantage would prove to be impossible to overcome. Money would allow companies such as General Electric to run numerous glamorous advertisements that the gas refrigerator companies were unable to match. In 1923, there were eight manufacturers of gas absorption refrigerators. By 1926, there were only three, and of these three only one would manufacture refrigerators in mass production (11). The downfall of the gas refrigerator was due to three things: the lack of capital available to the manufacturers; the stagnation of gas companies compared to the meteoric rise of electric companies; and the late arrival of the gas type model. The refrigerators in 1930s Greenbelt were most likely electric, especially if the one featured in the Greenbelt Museum (for a complete description of this artifact, click here. By the 1930s the gas refrigerator had been phased out and the electric refrigerator dominated the market. The majority of refrigerators of that era were equipped with compressors and were electric (for a description of refrigerators of that era, click here.) So, despite their sound technology, gas refrigerators never caught on in Greenbelt or anywhere else.