Most laboratories require some form of refrigeration to store samples, reagents and analytes. Dedicated laboratory refrigerators are normally required for this purpose, as domestic units tend not to provide the necessary stable and predictable temperatures and may not offer sufficient protection against accidents or explosions. Most laboratory refrigerators and freezers are equipped with alarms to warn against significant temperature deviation, as well as monitoring systems to record any alterations in temperature.
Laboratory refrigerators come in various sizes, from benchtop models for convenience, to upright models for storing larger quantities of reagents and freeze-dried products.
In the 11th century, the refrigerated coil, which was able to condense aromatic vapors, was invented by the Persian scientist Ibn Sina (Avicenna). He used refrigerated tubing to distill the essential oils.
Artificial refrigeration was demonstrated for the first time by William Cullen of Glasgow University, UK.
The first refrigeration machine based on vapor rather than liquid was invented by Oliver Evans.
Michael Faraday, the renowned scientist and inventor, became the first to demonstrate that liquefaction of ammonia caused cooling.
The first ice-making machine was invented by John Gorrie.
James Harrison, an Australian, was commissioned by a brewery to build a machine that could cool beer. He successfully developed vapor-compression refrigeration, which was almost immediately taken up by the brewing industry and was also widely used by meatpacking factories.
Harrison’s initial design was refined by Ferdinand Carré of France. Carré’s device used rapidly expanding ammonia as the coolant in place of air.
A continuous process of liquefying large volumes of gas was invented by the German engineer Carl von Linde. This paved the way for the development of the modern refrigeration industry. In 1878, Carl von Linde went on to found the company Lindes Eismaschinen AG (Society for Lindes Ice Machines), which now operates as Linde Group.
Arnold Gross and Edmund Copeland founded the Leonard Refrigerator Company (later known as the Electro-Automatic Refrigerating Company).
Carl von Linde was granted a patent for the liquefaction of air following his continued interest in the development of lower temperature systems.
A patent was issued for the “Refridgeator” (ice box), as invented by Henry Trost.
The first alternative to the ice box, the DOMELRE (DOMestic ELectric REfrigerator), was launched. This was a single-compartment unit housing an internal freezer sub-compartment.
The company Guardian Frigerato was founded by Alfred Mellowes and began to build standalone refrigerators for domestic use. The company was later purchased by General Motors and renamed Frigidaire.
Swedish students Baltzar von Platen and Carl Munters invented the absorption refrigerator, submitting the design as part of their degree studies. The heat source that initiated the process could be fuelled by electricity, gas or kerosene, making the system extremely flexible. The commercial potential of the absorption refrigerator was recognized by Electrolux, who commercialized the invention and enjoyed its worldwide success.
The Frigidaire Company released a self-contained refrigerator which, for the first time, allowed all components of the device (including condenser, motor and compressor) to be contained in one unit.
Electrolux launched its first refrigerator, the D-model. This had a volume of 91 liters, with a cooling unit and electrical fittings built into a ‘’hump.’’
General Electric (GE) introduced the “Monitor-Top” refrigerator, the most successful refrigerator of its time and the first to be widely used. Over 1,000,000 units were produced, and many functioning examples still exist today. A great deal of heat was emitted from the compressor assembly of this model, which was positioned above the cooling cabinet. These refrigerators used hazardous chemicals (methyl formate of sulfur dioxide) as the refrigerating medium.
The first built-in refrigerator, the model “M3,” was introduced by Electrolux. Previous models had all been freestanding. In the same year, Frigidaire released the Hydrator with an adjustable slot to regulate the amount of air allowed in.
The first air-cooled refrigerator, the model “L1,” was produced by Electrolux. This was considered a technological breakthrough. Unlike the previous model D refrigerator, which required both a power source and running water to function, the L1 used air to cool the ammonia, making it independent of a water source. This permitted the refrigerator for the first time to become a ‘standalone’ unit, allowing for much greater flexibility in its use.
DuPont began to produce commercial quantities of the chlorofluorocarbon coolant, Freon, as an alternative to hazardous agents, such as sulfur dioxide, that had been used previously. This advance allowed the refrigerator market to expand even faster.
The first refrigerator incorporating shelves on the inside of the door was launched by Crosley.
GE introduced a refrigerator with a dedicated heat control, allowing users to adjust the internal temperature of the refrigerator. However, as this electrical device was not grounded, many customers reported receiving unpleasant electric shocks.
During the 1940s, separate freezers began to be marketed, although they were not mass produced for domestic use until after the Second World War. Prior to this time, freezers were only available as the ice-cube compartment within the refrigerator unit. The war years saw a halt in developments in refrigerators and freezers as many companies were diverted into manufacturing machinery for the war effort.
GE introduced the first combined refrigerator-freezer unit with separate external doors for both compartments.
1950s and 1960s
During the 1950s and 1960s, many cosmetic advances were made to refrigerators used in the home, including the development of drink and ice dispensers, revolving shelves and coordinated colors. However, few advances were made to the fundamental technology, and the laboratory refrigerator was largely unchanged during this time.
Frigidaire launched the first frostless fridge, removing for the first time the need for frequent defrosting.
ScienTemp began manufacturing laboratory freezers.
Early in the 1970s, NuAire was awarded a contract to design and manufacture the first modern biological safety cabinet to meet U.S. National Institutes of Health Specifications. This unit was known as the “Laminar Flow Biological Safety Cabinet”.
Responding to environmental concerns and the ongoing energy crisis, Sears launched the Coldspot Power Miser, which claimed to use 40 percent less electricity than its competitors.
SANYO developed their first ultralow temperature (ULT) freezer, the MDF-2135, capable of achieving temperatures of -135 °C.
SANYO developed the world’s lowest temperature freezer, the MDF-1155, reaching temperatures of -152 °C.
In response to growing concern about the environmental impact of CFCs, the use of Freon was discontinued in refrigerators. Freon was replaced by the non-ozone-depleting gas, tetrafluoroethane.
SANYO introduced the world’s first vacuum-insulated freezer, the ULT freezer MDFU70V, which operated at -86 °C. The vacuum panels offered greater internal storage without impacting external dimensions.
New Brunswick Scientific (NBS), introduced the space-saving Innova® Model U101, the world’s first personal-sized, upright ULT freezer that fits on or under the bench, enabling scientists the security and convenience of being able to keep their samples directly in their lab. The U101 featured use of vacuum insulation panel technology to maximize internal storage without impacting external dimensions.
NBS was among the first to offer an eco-friendly and cost-saving “Green Freezer” line in which detrimental HFC refrigerants were replaced with hydrocarbon-based refrigerants. The new design significantly lowered energy consumption and operating costs. These freezers are not available in the U.S., where use of hydrocarbon refrigerators is prohibited.
LABREPCO launched the “Futura” media storage refrigerator for the storage of cell cultures that required 45 percent less energy than standard laboratory refrigerators.
Marvel Scientific introduced a new series of general purpose lab refrigerators featuring enhanced microprocessor technology and its exclusive MicroSentry™ scientific refrigeration monitor for superior temperature accuracy, control and monitoring of critical contents.
NBS launched a new line of high-efficiency freezers (HEF™) that offered a number of innovations. The combination of vacuum insulation panel technology, new and improved circulation and compressor systems, and in 50 Hz models the use of hydrocarbonbased refrigerants, allowed these freezers to consume up to 65 percent less electricity than competitive units.
SANYO launched the world’s safest ULT freezer with -86 Dual°Cool™ technology. This freezer avoided conventional cascade refrigeration technology by using two completely independent one-compressor, autocascade cooling systems, each capable of maintaining ultra-low temperatures.
Future of Laboratory Fridges and Freezers
Future innovations in freezer technology are likely to center on the development of alternative safe and effective refrigerants. Refrigerants are currently required to have an Ozone Depleting Potential (ODP) of zero, to be effective in conventional refrigeration machinery, to be non-toxic, non-flammable, and to have low global warming potential (GWP). It is very difficult to meet all these requirements. Hydrocarbon refrigerants, which meet many of these criteria and are widely used in Europe, are currently banned in the U.S. due to concerns over flammability.
An alternative refrigerant that may be used in the future is carbon dioxide, which was used in the early days of refrigeration, but fell out of use during the 1950s with the introduction of efficient halocarbon refrigerants. Experts predict that carbon dioxide will be increasingly used in a variety of ways, including in high-pressure carbon dioxide compressors for refrigeration and as a volatile secondary coolant.