Antifreeze
Overview
Antifreeze is a freeze preventive used in internal combustion engine
Internal combustion engine
The internal combustion engine is an engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber. In an internal combustion engine, the expansion of the high-temperature and high -pressure gases produced by combustion apply direct force to some component of the engine...

s and other heat transfer applications, such as HVAC
HVAC
HVAC refers to technology of indoor or automotive environmental comfort. HVAC system design is a major subdiscipline of mechanical engineering, based on the principles of thermodynamics, fluid mechanics, and heat transfer...

 chiller
Chiller
A chiller is a machine that removes heat from a liquid via a vapor-compression or absorption refrigeration cycle. This liquid can then be circulated through a heat exchanger to cool air or equipment as required.-Use in air conditioning:...

s and solar water heaters.

The purpose of antifreeze is to prevent a rigid enclosure from undergoing catastrophic deformation due to expansion when water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...

 turns to ice
Ice
Ice is water frozen into the solid state. Usually ice is the phase known as ice Ih, which is the most abundant of the varying solid phases on the Earth's surface. It can appear transparent or opaque bluish-white color, depending on the presence of impurities or air inclusions...

. Antifreezes are chemical compounds added to water to reduce the freezing point
Freezing Point
Freezing Point is a news journal in the People's Republic of China which has been the subject of controversy over its criticism of Communist Party officials and the sympathetic ear it lent to a Chinese historian who had criticized official history textbooks...

 of the mixture below the lowest temperature
Temperature
Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...

 that the system is likely to encounter.
Encyclopedia
Antifreeze is a freeze preventive used in internal combustion engine
Internal combustion engine
The internal combustion engine is an engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber. In an internal combustion engine, the expansion of the high-temperature and high -pressure gases produced by combustion apply direct force to some component of the engine...

s and other heat transfer applications, such as HVAC
HVAC
HVAC refers to technology of indoor or automotive environmental comfort. HVAC system design is a major subdiscipline of mechanical engineering, based on the principles of thermodynamics, fluid mechanics, and heat transfer...

 chiller
Chiller
A chiller is a machine that removes heat from a liquid via a vapor-compression or absorption refrigeration cycle. This liquid can then be circulated through a heat exchanger to cool air or equipment as required.-Use in air conditioning:...

s and solar water heaters.

The purpose of antifreeze is to prevent a rigid enclosure from undergoing catastrophic deformation due to expansion when water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...

 turns to ice
Ice
Ice is water frozen into the solid state. Usually ice is the phase known as ice Ih, which is the most abundant of the varying solid phases on the Earth's surface. It can appear transparent or opaque bluish-white color, depending on the presence of impurities or air inclusions...

. Antifreezes are chemical compounds added to water to reduce the freezing point
Freezing Point
Freezing Point is a news journal in the People's Republic of China which has been the subject of controversy over its criticism of Communist Party officials and the sympathetic ear it lent to a Chinese historian who had criticized official history textbooks...

 of the mixture below the lowest temperature
Temperature
Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...

 that the system is likely to encounter. Either the additive or the mixture may be referred to as antifreeze.

An antifreeze mixture achieves freezing point depression for a cold environment and also achieves boiling point elevation to enable higher liquid temperatures. This is described as the action of a colligative agent, which can properly be referred to as both antifreeze and "anti-boil" when used for both properties. Careful selection of an antifreeze can enable a wide temperature range in which the mixture remains in the liquid phase, which is critical to efficient heat transfer
Heat transfer
Heat transfer is a discipline of thermal engineering that concerns the exchange of thermal energy from one physical system to another. Heat transfer is classified into various mechanisms, such as heat conduction, convection, thermal radiation, and phase-change transfer...

 and the proper functioning of heat exchanger
Heat exchanger
A heat exchanger is a piece of equipment built for efficient heat transfer from one medium to another. The media may be separated by a solid wall, so that they never mix, or they may be in direct contact...

s.

Automotive and internal combustion engine use

Most automotive engines are "water"-cooled to remove waste heat
Waste heat
Waste heat sometimes called Secondary heat or Low-grade heat refers to heat produced by machines, electrical equipment and industrial processes for which no useful application is found. Energy is often produced by a heat engine, running on a source of high-temperature heat...

, although the "water" is actually antifreeze/water mixture and not plain water. The term engine coolant is widely used in the automotive industry, which covers its primary function of convective heat transfer
Convective heat transfer
Convective heat transfer, often referred to as convection, is the transfer of heat from one place to another by the movement of fluids. The presence of bulk motion of the fluid enhances the heat transfer between the solid surface and the fluid. Convection is usually the dominant form of heat...

 for internal combustion engine
Internal combustion engine
The internal combustion engine is an engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber. In an internal combustion engine, the expansion of the high-temperature and high -pressure gases produced by combustion apply direct force to some component of the engine...

s. When used in an automotive context, corrosion inhibitors are added to help protect vehicles' radiators
Radiator (engine cooling)
Radiators are used for cooling internal combustion engines, mainly in automobiles but also in piston-engined aircraft, railway locomotives, motorcycles, stationary generating plant or any similar use of such an engine....

, which often contain a range of electrochemically incompatible metals (aluminium
Aluminium
Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....

, cast iron
Cast iron
Cast iron is derived from pig iron, and while it usually refers to gray iron, it also identifies a large group of ferrous alloys which solidify with a eutectic. The color of a fractured surface can be used to identify an alloy. White cast iron is named after its white surface when fractured, due...

, copper
Copper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...

, brass
Brass
Brass is an alloy of copper and zinc; the proportions of zinc and copper can be varied to create a range of brasses with varying properties.In comparison, bronze is principally an alloy of copper and tin...

, solder
Solder
Solder is a fusible metal alloy used to join together metal workpieces and having a melting point below that of the workpiece.Soft solder is what is most often thought of when solder or soldering are mentioned and it typically has a melting range of . It is commonly used in electronics and...

, et cetera). Water pump seal lubricant is also added.

Antifreeze was developed to overcome the shortcomings of water as a heat transfer fluid. In some engines freeze plugs are placed in areas of the engine block where coolant flows in order to protect the engine from freeze damage if the ambient temperature drops below the freezing point of the antifreeze/water mixture. These should not be confused with core plug
Core plug
Core plugs, sometimes wrongly called freeze plugs or frost plugs, are plugs that fill the core holes found on water-cooled internal combustion engines....

s, whose purpose is to allow removal of sand used in the casting process of engine blocks (core plugs will be pushed out if the coolant freezes, though).

On the other hand, if the engine coolant gets too hot, it might boil while inside the engine, causing voids
Critical heat flux
Critical heat flux describes the thermal limit of a phenomenon where a phase change occurs during heating , which suddenly decreases the efficiency of heat transfer, thus causing localised overheating of the heating surface.The Critical heat flux for ignition is the lowest thermal load per unit...

 (pockets of steam), leading to localized hot spots and the catastrophic failure of the engine. If plain water were to be used as an engine coolant, it would promote galvanic corrosion. Proper engine coolant and a pressurized coolant system can help obviate the problems which make plain water incompatible with automotive engines. With proper antifreeze a wide temperature range can be tolerated by the engine coolant, such as -34 F to 265 °F (129.4 °C) for 50% (by volume) propylene glycol
Propylene glycol
Propylene glycol, also called 1,2-propanediol or propane-1,2-diol, is an organic compound with formula C3H8O2 or HO-CH2-CHOH-CH3...

 diluted with water and a 15 psi
Pounds per square inch
The pound per square inch or, more accurately, pound-force per square inch is a unit of pressure or of stress based on avoirdupois units...

 pressurized coolant system.

Early engine coolant antifreeze was methanol
Methanol
Methanol, also known as methyl alcohol, wood alcohol, wood naphtha or wood spirits, is a chemical with the formula CH3OH . It is the simplest alcohol, and is a light, volatile, colorless, flammable liquid with a distinctive odor very similar to, but slightly sweeter than, ethanol...

 (methyl alcohol), still used in windshield washer fluid. As radiator caps were vented, not sealed, the methanol was lost to evaporation, requiring frequent replenishment to avoid freezing of the coolant. Methanol also accelerates corrosion of the metals, especially aluminium, used in the engine and cooling systems. Ethylene glycol
Ethylene glycol
Ethylene glycol is an organic compound widely used as an automotive antifreeze and a precursor to polymers. In its pure form, it is an odorless, colorless, syrupy, sweet-tasting liquid...

 was developed, and soon replaced methanol as an engine cooling system antifreeze. It has a very low volatility compared to methanol and to water.

Other uses

The most common water-based antifreeze solutions used in electronics cooling are mixtures of water and either ethylene glycol (EGW) or propylene glycol (PGW). The use of ethylene glycol has a longer history, especially in the automotive industry. However, EGW solutions formulated for the automotive industry often have silicate based rust inhibitors that can coat and/or clog heat exchanger surfaces. The use of PGW as a coolant is becoming more common primarily because it is environmentally friendly and non-toxic. Ethylene glycol is listed as a toxic chemical requiring care in handling and disposal.

Ethylene glycol has desirable thermal properties, including a high boiling point, low freezing point, stability over a wide range of temperatures, and high specific heat and thermal conductivity. It also has a low viscosity and, therefore reduced pumping requirements. Although EGW has more desirable physical properties than PGW, the latter coolant is used in applications where toxicity might be a concern. PGW is generally recognized as safe for use in food or food processing applications, and can also be used in enclosed spaces.

Methanol

Methanol (also known as methyl alcohol, carbinol, wood alcohol, wood naphtha or wood spirits) is a chemical compound with chemical formula
Chemical formula
A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....

 CH3OH. It is the simplest alcohol, and is a light, volatile, colorless, flammable, poisonous liquid with a distinctive odor that is somewhat milder and sweeter than ethanol
Ethanol
Ethanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatile, flammable, colorless liquid. It is a psychoactive drug and one of the oldest recreational drugs. Best known as the type of alcohol found in alcoholic beverages, it is also used in thermometers, as a...

 (ethyl alcohol). At room temperature it is a polar
Chemical polarity
In chemistry, polarity refers to a separation of electric charge leading to a molecule or its chemical groups having an electric dipole or multipole moment. Polar molecules interact through dipole–dipole intermolecular forces and hydrogen bonds. Molecular polarity is dependent on the difference in...

 solvent and is used as an antifreeze, solvent, fuel, and as a denaturant for ethyl alcohol. It is not popular for machinery, but may be found in automotive windshield washer fluid
Windshield washer fluid
Windshield washer fluid is a fluid for motor vehicles that is used in cleaning the windshield with the windshield wiper while the vehicle is being driven.-Delivery system:A control within the car can be operated to squirt fluid onto the windshield, typically using an...

, de-icer
Deicing
For snow and ice control on roadways and similar facilities, see Snow removalDe-icing is defined as removal of snow, ice or frost from a surface...

s, and gasoline additive
Gasoline additive
Gasoline additives increase gasoline's octane rating or act as corrosion inhibitors or lubricants, thus allowing the use of higher compression ratios for greater efficiency and power, however some carry heavy environmental risks...

s.

Ethylene glycol

Ethylene glycol solutions became available in 1926 and were marketed as "permanent antifreeze" since the higher boiling points provided advantages for summertime use as well as during cold weather. They are used today for a variety of applications, including automobile
Automobile
An automobile, autocar, motor car or car is a wheeled motor vehicle used for transporting passengers, which also carries its own engine or motor...

s.

Poisoning

Ethylene glycol is toxic to humans, as well as to other animals, and should therefore be handled and disposed of properly. It has a sweet taste that can contribute to its accidental ingestion or its deliberate use as a murder weapon, as attributed by sensational media reports concerning it. Such poisoning is difficult to identify without specialized testing, as it often mimics other illnesses, and various symptoms can result from such poisoning, including severe diarrhea and vomiting. Some ethylene glycol antifreeze contains an embittering agent such as denatonium
Denatonium
Denatonium, usually available as denatonium benzoate and as denatonium saccharide, is the bitterest chemical compound known; with bitterness thresholds of 0.05 ppm for the benzoate and 0.01 ppm for the saccharide.It was discovered in 1958 during research on local anesthetics by Macfarlan...

 to help discourage either accidental or deliberate consumption.

Glycerol

Once used for automotive antifreeze, glycerol
Glycerol
Glycerol is a simple polyol compound. It is a colorless, odorless, viscous liquid that is widely used in pharmaceutical formulations. Glycerol has three hydroxyl groups that are responsible for its solubility in water and its hygroscopic nature. The glycerol backbone is central to all lipids...

 has the advantage of being non-toxic and could be used in the future for some applications.

Propylene glycol

Propylene glycol, on the other hand, is considerably less toxic and may be labeled as "non-toxic antifreeze". It is used as antifreeze where ethylene glycol would be inappropriate, such as in food-processing systems or in water pipes in homes where incidental ingestion may be possible.

Propylene glycol oxidizes when exposed to air and heat, forming lactic acid
Lactic acid
Lactic acid, also known as milk acid, is a chemical compound that plays a role in various biochemical processes and was first isolated in 1780 by the Swedish chemist Carl Wilhelm Scheele. Lactic acid is a carboxylic acid with the chemical formula C3H6O3...

. If not properly inhibited, this fluid can be very corrosive, so pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...

 buffering agents are often added to propylene glycol, to prevent acidic corrosion of metal components.

Besides cooling system breakdown, biological fouling also occurs. Once bacterial slime starts, the corrosion rate of the system increases. Maintenance of systems using glycol solution includes regular monitoring of freeze protection, pH, specific gravity
Specific gravity
Specific gravity is the ratio of the density of a substance to the density of a reference substance. Apparent specific gravity is the ratio of the weight of a volume of the substance to the weight of an equal volume of the reference substance. The reference substance is nearly always water for...

, inhibitor level, color, and biological contamination.

Propylene glycol should be replaced when it turns a reddish color.

Measuring the freeze point

Once antifreeze has been mixed with water and put into use, it periodically needs to be maintained. If engine coolant leaks, boils, or if the radiator needs to be drained and refilled, the antifreeze's freeze protection will need to be considered. In other cases a vehicle may need to be operated in a colder environment, requiring more antifreeze and less water. Three methods are commonly employed to determine the freeze point of the solution:
  1. Specific gravity
    Specific gravity
    Specific gravity is the ratio of the density of a substance to the density of a reference substance. Apparent specific gravity is the ratio of the weight of a volume of the substance to the weight of an equal volume of the reference substance. The reference substance is nearly always water for...

    — (using a hydrometer
    Hydrometer
    A hydrometer is an instrument used to measure the specific gravity of liquids; that is, the ratio of the density of the liquid to the density of water....

     or some sort of floating indicator),
  2. Refractometer
    Refractometer
    A refractometer is a laboratory or field device for the measurement of an index of refraction . The index of refraction is calculated from Snell's law and can be calculated from the composition of the material using the Gladstone-Dale relation....

    — which uses the optical properties of the solution, and
  3. Test strips— specialized, disposable indicators made for this purpose.


Although ethylene glycol hydrometers are widely available and mass-marketed for antifreeze testing, they give false readings at high temperatures because specific gravity changes with temperature. Propylene glycol solutions cannot be tested using specific gravity because of ambiguous results (40% and 100% solutions have the same specific gravity).

Corrosion Inhibitors

Most commercial antifreeze formulations include corrosion inhibiting
Corrosion inhibitor
A corrosion inhibitor is a chemical compound that, when added to a liquid or gas, decreases the corrosion rate of a material, typically a metal or an alloy. The effectiveness of a corrosion inhibitor depends on fluid composition, quantity of water, and flow regime...

 compounds, and a colored dye
Dye
A dye is a colored substance that has an affinity to the substrate to which it is being applied. The dye is generally applied in an aqueous solution, and requires a mordant to improve the fastness of the dye on the fiber....

 (commonly a green, red, orange, yellow, or blue fluorescent) to aid in identification. A 1:1 dilution
Concentration
In chemistry, concentration is defined as the abundance of a constituent divided by the total volume of a mixture. Four types can be distinguished: mass concentration, molar concentration, number concentration, and volume concentration...

 with water is usually used, resulting in a freezing point of about -34 F, depending on the formulation. In warmer or colder areas, weaker or stronger dilutions are used, respectively, but a range of 40%/60% to 60%/40% is frequently specified to ensure corrosion protection, and 70%/30% for maximum freeze prevention down to -84 F.

Traditional inhibitors

Traditionally, there were two major corrosion inhibitors used in vehicles: silicate
Silicate
A silicate is a compound containing a silicon bearing anion. The great majority of silicates are oxides, but hexafluorosilicate and other anions are also included. This article focuses mainly on the Si-O anions. Silicates comprise the majority of the earth's crust, as well as the other...

s and phosphate
Phosphate
A phosphate, an inorganic chemical, is a salt of phosphoric acid. In organic chemistry, a phosphate, or organophosphate, is an ester of phosphoric acid. Organic phosphates are important in biochemistry and biogeochemistry or ecology. Inorganic phosphates are mined to obtain phosphorus for use in...

s. American made vehicles traditionally used both silicates and phosphates. European makes contain phosphates and other inhibitors, but no silicates. Japanese makes traditionally use phosphates and other inhibitors, but no silicates.

Organic acid technology

Certain cars are built with organic acid technology (OAT) antifreeze (e.g., DEX-COOL), or with a hybrid organic acid technology (HOAT) formulation (e.g., Zerex G-05), both of which are claimed to have an extended service life of five years or 240000 km (149,129.5 mi).

DEX-COOL specifically has caused controversy
Controversy
Controversy is a state of prolonged public dispute or debate, usually concerning a matter of opinion. The word was coined from the Latin controversia, as a composite of controversus – "turned in an opposite direction," from contra – "against" – and vertere – to turn, or versus , hence, "to turn...

. Litigation has linked it with intake manifold gasket failures in General Motors
General Motors
General Motors Company , commonly known as GM, formerly incorporated as General Motors Corporation, is an American multinational automotive corporation headquartered in Detroit, Michigan and the world's second-largest automaker in 2010...

' (GM's) 3.1L and 3.4L engines, and with other failures in 3.8L and 4.3L engines. Class action
Class action
In law, a class action, a class suit, or a representative action is a form of lawsuit in which a large group of people collectively bring a claim to court and/or in which a class of defendants is being sued...

 lawsuits were registered in several states, and in Canada, to address some of these claims. The first of these to reach a decision was in Missouri where a settlement was announced early in December 2007. Late in March 2008, GM agreed to compensate complainants in the remaining 49 states. GM (Motors Liquidation Company
Motors Liquidation Company
Motors Liquidation Company , formerly MTLQQ on OTC Pink, was the company left to settle past liability claims from General Motors Chapter 11 reorganization...

) filed for bankruptcy in 2009, which tied up the outstanding claims until a court determines who gets paid.

According to the DEX-COOL manufacturer, "mixing a 'green' [non-OAT] coolant with DEX-COOL reduces the batch's change interval to 2 years or 30,000 miles, but will otherwise cause no damage to the engine." DEX-COOL antifreeze uses two inhibitors: sebacate and 2-EHA (2-ethylhexanoic acid
2-Ethylhexanoic acid
2-Ethylhexanoic acid is the organic compound with the formula CH33CHCO2H. This carboxylic acid is widely used to prepare metal derivatives that are soluble in nonpolar organic solvents. These lipophilic metal-containing derivatives are used as catalysts in polymerizations. For example, tin...

), the latter which works well with the hard water
Hard water
Hard water is water that has high mineral content . Hard water has high concentrations of Ca2+ and Mg2+ ions. Hard water is generally not harmful to one's health but can pose serious problems in industrial settings, where water hardness is monitored to avoid costly breakdowns in boilers, cooling...

 found in the US, but is a plasticizer
Plasticizer
Plasticizers or dispersants are additives that increase the plasticity or fluidity of the material to which they are added; these include plastics, cement, concrete, wallboard, and clay. Although the same compounds are often used for both plastics and concretes the desired effects and results are...

 which can cause gaskets to leak.

According to internal GM documents, the ultimate culprit appears to be operating vehicles for long periods of time with low coolant levels. The low coolant is caused by pressure caps that fail in the open position. (The new caps and recovery bottles were introduced at the same time as DEX-COOL). This exposes hot engine components to air and vapors, causing corrosion and contamination of the coolant with iron oxide particles, which in turn can aggravate the pressure cap problem as contamination holds the caps open permanently.

Honda and Toyota's new extended life coolant use OAT with sebacate but without the 2-EHA. Some added phosphates provide protection while the OAT builds up. Honda specifically excludes 2-EHA from their formulas.

Typically OAT antifreeze contains an orange dye to differentiate it from the conventional glycol-based coolants (green or yellow). Some of the newer OAT coolants claim to be compatible with all types of OAT and glycol-based coolants; these are typically green or yellow in color (for a table of colors, see )

Hybrid organic acid technology

HOAT coolants typically mix an OAT with a traditional inhibitor, such as silicates or phosphates.

G05 is a low-silicate, phosphate free formula that includes the benzoate inhibitor.

Additives

All automotive antifreeze formulations, including the newer organic acid (OAT antifreeze) formulations, are environmentally hazardous because of the blend of additives (around 5%), including lubricants, buffers and corrosion inhibitors. Because the additives in antifreeze are proprietary, the material safety data sheet
Material safety data sheet
A Material Safety Data Sheet is a form with data regarding the properties of a particular substance....

s (MSDS) provided by the manufacturer list only those compounds which are considered to be significant safety hazards when used in accordance with the manufacturer's recommendations. Common additives include sodium silicate
Sodium silicate
Sodium silicate is the common name for a compound sodium metasilicate, Na2SiO3, also known as water glass or liquid glass. It is available in aqueous solution and in solid form and is used in cements, passive fire protection, refractories, textile and lumber processing, and automobiles...

, disodium phosphate
Disodium phosphate
Disodium hydrogen phosphate is a sodium salt of phosphoric acid. It is a white powder that is highly hygroscopic and water soluble. It is therefore used commercially as an anti-caking additive in powdered products. It is also known as disodium hydrogen orthophosphate, sodium hydrogen phosphate...

, sodium molybdate
Sodium molybdate
Sodium molybdate, Na2MoO4, is useful as a source of molybdenum. It is often found as the dihydrate, Na2MoO4·2H2O.The molybdate anion is tetrahedral. Two sodium cations coordinate with every one anion.-History:...

, sodium borate, and dextrin
Dextrin
Dextrins are a group of low-molecular-weight carbohydrates produced by the hydrolysis of starch or glycogen. Dextrins are mixtures of polymers of D-glucose units linked by α- or α- glycosidic bonds....

 (hydroxyethyl starch). Disodium fluorescein dyes are added to antifreeze to help trace the source of leaks, and as an identifier since some different formulations are incompatible.

Automotive antifreeze has a characteristic odor due to the additive tolytriazole, a corrosion inhibitor. The unpleasant odor in industrial use tolytriazole comes from impurities in the product that are formed from the toluidine isomers (ortho-, meta- and para-toluidine) and meta-diamino toluene which are side-products in the manufacture of tolytriazole.
These side-products are highly reactive and produce volatile aromatic amines which are responsible for the unpleasant odor.

See also

  • Air cooling
  • Colligative properties
    Colligative properties
    Colligative properties are properties of solutions that depend on the number of molecules in a given volume of solvent and not on the properties/identity of the molecules. Colligative properties include: relative lowering of vapor pressure; elevation of boiling point; depression of freezing point...

  • Cryoprotectant
    Cryoprotectant
    A cryoprotectant is a substance that is used to protect biological tissue from freezing damage . Arctic and Antarctic insects, fish, amphibians and reptiles create cryoprotectants in their bodies to minimize freezing damage during cold winter periods. Insects most often use sugars or polyols as...

  • Heater core
    Heater Core
    A heater core is a radiator-like device used in heating the cabin of a vehicle. Hot coolant from the vehicle's engine is passed through a winding tube of the core, a heat exchanger between coolant and cabin air...

  • Ice melt
  • Internal combustion engine cooling
  • Radiator
    Radiator
    Radiators are heat exchangers used to transfer thermal energy from one medium to another for the purpose of cooling and heating. The majority of radiators are constructed to function in automobiles, buildings, and electronics...

  • Water cooling
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK