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A defogger, demister, or defroster is a system to clear condensation and thaw frost from the windshield, backglass, or side windows of a motor vehicle. The rear window defroster was invented by German automobile engineer Heinz Kunert. [1]
For primary defogging, heat is generally provided by the vehicle's engine coolant via the heater core; fresh air is blown through the heater core and then ducted to and distributed over the interior surface of the windshield by a blower. This air is in many cases first cooled down and dehumidified by passing it through the vehicle's operating air conditioning evaporator. Such dehumidification, when followed by a reheating, makes the defogging more effective and faster, for the dry warm air has a greater capacity of absorbing water from the glass at which it is directed (with respect to the moist warm air provided by the heater alone, and the dry cold air provided by the air conditioning system alone). However, whenever the vehicle is equipped with an air conditioning system, care must be taken to keep it in an operational state for the primary defogger to operate optimally. Also, at very low ambient temperatures, the air conditioning system might not turn on, in order to prevent possible compressor damage. In modern vehicles, running this type of defogger often automatically switches the air conditioning system on, without further action required.
Secondary defoggers, such as those used on a vehicle's backglass and/or side view mirrors, often consist of a series of parallel linear resistive conductors in or on the glass. When power is applied, these conductors heat up, thawing ice and evaporating condensation from the glass. These conductors may be composed of a silver-ceramic material printed and baked onto the interior surface of the glass, or may be a series of very fine wires embedded within the glass. The surface-printed variety is prone to damage by abrasion, but can be repaired easily with a conductive paint material.
Various terms are applied to secondary defoggers, such as "electric window defogger" (EWD), "rear window defogger" (RWD), etc.
Resistive-heat defoggers are usually equipped with an automatic timer to operate for a set time period of 10 to 15 minutes before switching off. This is because most defogging is achieved within that timeframe, after which the vehicle's heater has usually brought the interior of the vehicle to a warm enough temperature that the fog does not recur. However, if this is not the case, the driver may activate the system again once it has timed out. There is usually a telltale on the vehicle dashboard, often on the defogger switch, to let the driver know.
Heating, ventilation, and air conditioning (HVAC) is the technology of indoor and vehicular environmental comfort. Its goal is to provide thermal comfort and acceptable indoor air quality. HVAC system design is a subdiscipline of mechanical engineering, based on the principles of thermodynamics, fluid mechanics and heat transfer. "Refrigeration" is sometimes added to the field's abbreviation, as HVAC&R or HVACR or "ventilation" is dropped, as in HACR.
A dehumidifier is an electrical appliance which reduces and maintains the level of humidity in the air, usually for health or comfort reasons, or to eliminate musty odor and to prevent the growth of mildew by extracting water from the air. It can be used for household, commercial, or industrial applications. Large dehumidifiers are used in commercial buildings such as indoor ice rinks and swimming pools, as well as manufacturing plants or storage warehouses.
A thermostat is a regulating device component which senses the temperature of a physical system and performs actions so that the system's temperature is maintained near a desired setpoint.
A refrigerator is a commercial and home appliance consisting of a thermally insulated compartment and a heat pump that transfers heat from its inside to its external environment so that its inside is cooled to a temperature below the room temperature. The refrigerator should be kept at or below 40° F and the freezer should be regulated at 0° F. Refrigeration is an essential food storage technique around the world. The lower temperature lowers the reproduction rate of bacteria, so the refrigerator reduces the rate of spoilage. A refrigerator maintains a temperature a few degrees above the freezing point of water. Optimum temperature range for perishable food storage is 3 to 5 °C. A similar device that maintains a temperature below the freezing point of water is called a freezer. The refrigerator replaced the icebox, which had been a common household appliance for almost a century and a half.
A heating element converts electrical energy into heat through the process of Joule heating. Electric current through the element encounters resistance, resulting in heating of the element. Unlike the Peltier effect, this process is independent of the direction of current.
Window film is a thin laminate film that can be installed to the interior or exterior of glass surfaces in automobiles and boats and also to the interior or exterior of glass in homes and buildings. It is usually made from polyethylene terephthalate (PET), a thermoplastic polymer resin of the polyester family, due to its clarity, tensile strength, dimensional stability, and ability to accept a variety of surface-applied or embedded treatments.
The CitiCar is an electric car produced from 1974 to 1977 by Sebring, Florida-based Sebring-Vanguard, Inc. After being bought out by Commuter Vehicles, Inc, Sebring-Vanguard produced the similar Comuta-Car and Comuta-Van from 1979 to 1982. Similarities to its exterior design can be spotted in the Danish Kewet and the later Norwegian Buddy. Accounting for all CitiCar variants, a total of 4,444 units were produced up to 1979, the most since 1945 for an electric car assembled in North America until surpassed by the Tesla Model S.
Auto-defrost, automatic defrost or self-defrosting is a technique which regularly defrosts the evaporator in a refrigerator or freezer. Appliances using this technique are often called frost free, frostless, or no-frost.
A glossary of terms relating to automotive design.
Quickclear is a European trademark used by the Ford Motor Company for its electrically heated windshield technology. Instaclear was the name used sometimes in the United States.
An absorption refrigerator is a refrigerator that uses a heat source to provide the energy needed to drive the cooling process. The system uses two coolants, the first of which performs evaporative cooling and is then absorbed into the second coolant; heat is needed to reset the two coolants to their initial states. The principle can also be used to air-condition buildings using the waste heat from a gas turbine or water heater. Using waste heat from a gas turbine makes the turbine very efficient because it first produces electricity, then hot water, and finally, air-conditioning—trigeneration. Absorption refrigerators are commonly used in recreational vehicles (RVs), campers, and caravans because the heat required to power them can be provided by a propane fuel burner, by a low-voltage DC electric heater or by a mains-powered electric heater. Unlike more common vapor-compression refrigeration systems, an absorption refrigerator can be produced with no moving parts other than the coolants.
Electric heating is a process in which electrical energy is converted to heat energy. Common applications include space heating, cooking, water heating and industrial processes. An electric heater is an electrical device that converts an electric current into heat. The heating element inside every electric heater is an electrical resistor, and works on the principle of Joule heating: an electric current passing through a resistor will convert that electrical energy into heat energy. Most modern electric heating devices use nichrome wire as the active element; the heating element, depicted on the right, uses nichrome wire supported by ceramic insulators.
An air source heat pump (ASHP) is a reversible heat pump which uses the outside air as a heat source when in heating mode, or as a heat sink when in cooling mode using the same vapor-compression refrigeration process and same external heat exchanger with a fan as used by air conditioners.
The Weather Eye was a trade name for a Nash Motors-designed fresh-air system for automobile passenger compartment heating, cooling, and ventilating. The Nash "All-Weather Eye" was the first automobile air conditioning system for the mass market. The use of the Weather Eye name for automobile passenger heating and air conditioning systems continued in American Motors Corporation (AMC) vehicles.
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. Fins attached to the core tubes serve to increase surface area for heat transfer to air that is forced past them by a fan, thereby heating the passenger compartment.
Air conditioning, often abbreviated as A/C or AC, is the process of removing heat and controlling the humidity of air in an enclosed space to achieve a more comfortable interior environment by use of powered "air conditioners" or a variety of other methods, including passive cooling and ventilative cooling. Air conditioning is a member of a family of systems and techniques that provide heating, ventilation, and air conditioning (HVAC).
Radiators are heat exchangers 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.
Akrep ("Scorpion") is a Turkish infantry mobility vehicle developed by Otokar Otobus Karoseri Sanayi AS. The first prototypes were completed in May 1993 and the first vehicles came off the production line in June 1994. In addition to light reconnaissance, the vehicles were used for escort, perimeter control, counter-insurgency, and light attack. The Akrep represented the latest offering in Otokar's portfolio of light vehicles for both civilian and military markets. Note that otokar comes from French autocar and designs busses that also can transport luggage. Passengers being at the higher level.
Heated glass is a resistance heater created when a transparent, electrically conductive coating is applied to float glass and then subjected to an electric current. The electric current in the coating creates heat energy, which warms the glass until the glass radiates heat.
Automobile air conditioning systems use air conditioning to cool the air in a vehicle.