Daimler-Benz DB 605
The Daimler-Benz DB 605 is a German aircraft engine, built during World War II. Developed from the DB 601, the DB 605 was used from 1942 to 1945 in the Messerschmitt Bf 109 fighter, the Bf 110 and Me 210C heavy fighters; the DB 610, a coupled "power system" powerplant comprising a pair of side-by-side configured examples of the DB 605, geared together in the front to turn a single output shaft — and which, like the similar DB 606 that it replaced, weighed 1,515 kg — was used in the A-3 and all A-5 variants of Germany's only operational heavy bomber, the Heinkel He 177A. License-built versions of the DB 605 were used in the Macchi C.205, Fiat G.55, Reggiane 2005 and some other Italian aircraft. It was initially used in the pusher-design Swedish Saab J21. 42,400 DB 605s of all kinds were built. The primary differences between the 605 and 601 were greater displacement, higher revolutions, higher compression ratio and a more powerful supercharger. Through careful study the engineers determined that the cylinders could be bored out to a larger diameter without affecting the strength of the existing block.
The difference was minimal, increasing from the 601's 150 mm cylinder bore to the 605's 154 mm, but this increased the overall displacement from 33.9 litres to 35.7. Altered valve timing increased the inlet period and improved the scavenging to give greater volumetric efficiency at higher speeds, which improved the maximum allowable RPM from 2,600 in the 601 to 2,800 in the 605; the combination of these changes raised power output from 1,350 PS to 1,475 PS. The engine was otherwise similar, notably in size, identical to the 601. However, its weight did increase from 700 to 756 kg. In other ways the engine was identical to the 601, being a 12-cylinder, inverted-V design. Both used. Fuel injection was powered by a pump supplying up to 90 bar and the oil system used three pumps with a separate 35-litre oil tank; the supercharger was advanced for the era in that it used a barometrically controlled hydraulic clutch which allowed the system to automatically compensate for changes in altitude. One major design difference was the switch from ball bearings to plain bearings which, when combined with poor grades of lubricants, led to serious problems in service, including engine fires.
Although Daimler-Benz redesigned the bearings and added oil slingers and their associated coolers, the RLM considered the DB 605 to be a "sick engine" and the problems had not been resolved by the end of the war. Like the 601, the 605 was designed to run on "B4" fuel with an octane rating of 87. In 1944 a series of newer engines was introduced, allowing the engine to run on the 100 octane "C3" fuel and optionally including fittings for various optional power-boosting agent dispensing systems, such as the MW50 methanol-water injection system, GM-1 nitrous oxide injection system; the DB 605AM, running on C3 and MW-50, saw power improved to 1,800 PS for takeoff. In mid-1944, the requirement for C3 was dropped and standard B4 fuel with MW-50 was used; the DB 605AS improved the maximum rated altitude by using a larger supercharger taken from the DB 603 but was otherwise similar to the A. The DB 605ASB's takeoff power was rated at 1,800 PS, while maintaining the high-altitude performance of the ASM.
The final version of the A-series was the DB 605ASC of 1945, which improved takeoff power to 2,000 PS. As early as 1942 Daimler had been working on an upgraded D-series engine that could run on either C2 or C3 fuel; the first of these, which appeared in late 1944, were a small series of DB 605DM, followed by the main production series, the DB 605DB/DC. These engines were fitted with an adjustable screw stop which allowed the use of either B4 fuel with MW-50, or C-3 fuel without MW-50, in which case the engine was designated DB 605DB, or the use of C-3 fuel with MW-50, in which case the engine was given the -DC suffix instead. In its DB-suffix form the engine generated 1,800 PS for take-off at 1.8 ata, while the DC was capable of 2,000 PS at 1.98 ata. If MW-50 was not available for use with the B4 fuel the throttle was limited to 1.45 ata for the entire flight. Thus, this series was ideally suited to catering for the chaotic fuel supply situation prevalent during the last months of the Third Reich.
These engines were used in the Bf 109G-10 and K-4 series. Production versions DB 605 A Standard fighter engine, up to 1475 PS, 605 AM with MW-50 system up to 1800 PS DB 605 AS Altitude optimized version of 605 A using the larger DB 603 supercharger, up to 1435 PS, ASM with MW-50 system and up to 1800 PS DB 605 ASB Altitude optimized late-war version of 605 AS using B4 fuel, ASBM with MW-50 system and up to 1800 PS DB 605 ASC Altitude optimized late-war version of 605 AS using C3 fuel, ASCM with MW-50 system and up to 2000 PS DB 605 B Same as 605 A but for use in twin-engined aircraft like Messerschmitt Bf 110, Me 210 DB 605 BS proposed version for twin-engined aircraft, derived from DB 605 AS DB 605 DB Improved 605 DM, standard MW-50 equipment, first version up to 1850 PS reduced to 1800 PS, B4 fuel DB 605 DC Improved 605 DM, standard MW-50 equipment, up to 2000 PS, C3 fuel DB 605 DM First DB 605 D version, standard MW-50 equipment, up to 1700 PS DB 605 E proposed version for twin-engined aircraft, derived from DB 605 D DB 605 L Similar to 605 D but with two-stage supercharger, 1700 PS, development stopped in December 1944 Fiat RA.1050 R.
C.58 Tifone Licence built / developed DB 605A-1 engines, built by Fiat in Italy. DB 610
A car is a wheeled motor vehicle used for transportation. Most definitions of car say they run on roads, seat one to eight people, have four tires, transport people rather than goods. Cars came into global use during the 20th century, developed economies depend on them; the year 1886 is regarded as the birth year of the modern car when German inventor Karl Benz patented his Benz Patent-Motorwagen. Cars became available in the early 20th century. One of the first cars accessible to the masses was the 1908 Model T, an American car manufactured by the Ford Motor Company. Cars were adopted in the US, where they replaced animal-drawn carriages and carts, but took much longer to be accepted in Western Europe and other parts of the world. Cars have controls for driving, passenger comfort, safety, controlling a variety of lights. Over the decades, additional features and controls have been added to vehicles, making them progressively more complex; these include rear reversing cameras, air conditioning, navigation systems, in-car entertainment.
Most cars in use in the 2010s are propelled by an internal combustion engine, fueled by the combustion of fossil fuels. Electric cars, which were invented early in the history of the car, began to become commercially available in 2008. There are benefits to car use; the costs include acquiring the vehicle, interest payments and maintenance, depreciation, driving time, parking fees and insurance. The costs to society include maintaining roads, land use, road congestion, air pollution, public health, health care, disposing of the vehicle at the end of its life. Road traffic accidents are the largest cause of injury-related deaths worldwide; the benefits include on-demand transportation, mobility and convenience. The societal benefits include economic benefits, such as job and wealth creation from the automotive industry, transportation provision, societal well-being from leisure and travel opportunities, revenue generation from the taxes. People's ability to move flexibly from place to place has far-reaching implications for the nature of societies.
There are around 1 billion cars in use worldwide. The numbers are increasing especially in China and other newly industrialized countries; the word car is believed to originate from the Latin word carrus or carrum, or the Middle English word carre. In turn, these originated from the Gaulish word karros, it referred to any wheeled horse-drawn vehicle, such as a cart, carriage, or wagon. "Motor car" is attested from 1895, is the usual formal name for cars in British English. "Autocar" is a variant, attested from 1895, but, now considered archaic. It means "self-propelled car"; the term "horseless carriage" was used by some to refer to the first cars at the time that they were being built, is attested from 1895. The word "automobile" is a classical compound derived from the Ancient Greek word autós, meaning "self", the Latin word mobilis, meaning "movable", it entered the English language from French, was first adopted by the Automobile Club of Great Britain in 1897. Over time, the word "automobile" fell out of favour in Britain, was replaced by "motor car".
"Automobile" remains chiefly North American as a formal or commercial term. An abbreviated form, "auto", was a common way to refer to cars in English, but is now considered old-fashioned; the word is still common as an adjective in American English in compound formations like "auto industry" and "auto mechanic". In Dutch and German, two languages related to English, the abbreviated form "auto" / "Auto", as well as the formal full version "automobiel" / "Automobil" are still used — in either the short form is the most regular word for "car"; the first working steam-powered vehicle was designed — and quite built — by Ferdinand Verbiest, a Flemish member of a Jesuit mission in China around 1672. It was a 65-cm-long scale-model toy for the Chinese Emperor, unable to carry a driver or a passenger, it is not known with certainty if Verbiest's model was built or run. Nicolas-Joseph Cugnot is credited with building the first full-scale, self-propelled mechanical vehicle or car in about 1769, he constructed two steam tractors for the French Army, one of, preserved in the French National Conservatory of Arts and Crafts.
His inventions were, handicapped by problems with water supply and maintaining steam pressure. In 1801, Richard Trevithick built and demonstrated his Puffing Devil road locomotive, believed by many to be the first demonstration of a steam-powered road vehicle, it was unable to maintain sufficient steam pressure for long periods and was of little practical use. The development of external combustion engines is detailed as part of the history of the car but treated separately from the development of true cars. A variety of steam-powered road vehicles were used during the first part of the 19th century, including steam cars, steam buses and steam rollers. Sentiment against them led to the Locomotive Acts of 1865. In 1807, Nicéphore Niépce and his brother Claude created what was the world's first internal combustion engine, but they chose to install it in a boat on the river Saone in France. Coincidentally, in 1807 the Swiss inventor François Isaac de Rivaz designed his own'de Rivaz internal combustion engine' and used it to develop the world's first vehicle to be powered by such an engine.
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 for heat transfer to air, forced past them, by a fan, thereby heating the passenger compartment; the internal combustion engine in most cars and trucks is cooled by a water and antifreeze mixture, circulated through the engine and radiator by a water pump to enable the radiator to give off engine heat to the atmosphere. Some of that coolant can be diverted through the heater core to give some engine heat to the cabin, or adjust the temperature of the conditioned air. A heater core is a small radiator located under the dashboard of the vehicle, it consists of conductive aluminium or brass tubing with cooling fins to increase surface area. Hot coolant passing through the heater core gives off heat before returning to the engine cooling circuit.
The squirrel cage fan of the vehicle's ventilation system forces air through the heater core to transfer heat from the coolant to the cabin air, directed into the vehicle through vents at various points. Once the engine has warmed up, the coolant is kept at a more or less constant temperature by the thermostat; the temperature of the air entering the vehicle's interior can be controlled by using a valve limiting the amount of coolant that goes through the heater core. Another method is blocking off the heater core with a door, directing part of the incoming air around the heater core so it does not get heated; some cars use a combination of these systems. Simpler systems allow the driver to control the door directly. More complicated systems use a combination of electromechanical actuators and thermistors to control the valve or doors to deliver air at a precise temperature value selected by the user. Cars with dual climate function may use a heater core split in two, where different amounts of coolant flow through the heater core on either side to obtain the desired heating.
In a car equipped with air conditioning, outside air, or cabin air if the recirculation flap has been set to close the external air passages, is first forced after being filtered by a cabin air filter, through the air conditioner's evaporator coil. This can be thought of as a heater core filled with cold liquid, undergoing a phase change to gas, a process which cools rather than heats the incoming air. In order to obtain the desired temperature incoming air may first be cooled by the air conditioning and heated again by the heater core. In a vehicle fitted with manual controls for the heater and air conditioning compressor, using both systems together will dehumidify the air in the cabin, as the evaporator coil removes moisture from the air due to condensation; this can result in increased air comfort levels inside the vehicle. Automatic temperature control systems can take the best course of action in regulating the compressor operation, amount of reheating and blower speed depending upon the external air temperature, the internal one and the cabin air temperature value or a rapid defrost effect requested by the user.
Because the heater core cools the heated coolant from the engine by transferring its heat to the cabin air, it can act as an auxiliary radiator for the engine. If the radiator is working improperly, the operator may turn the heat on in the passenger cabin, resulting in a certain cooling effect on the overheated engine coolant; this idea only works to a certain degree, as the heater core is not large enough nor does it have enough cold air going through it to cool large amounts of coolant significantly. The heater core is made up of small piping. Clogging of the piping may occur if the coolant system is not flushed or if the coolant is not changed regularly. If clogging occurs the heater core will not work properly. If coolant flow is restricted, heating capacity will be reduced or lost altogether if the heater core becomes blocked. Control valves may clog or get stuck. Where a blend door is used instead of a control valve as a method of controlling the air's heating amount, the door itself or its control mechanism can become stuck due to thermal expansion.
If the climate control unit is automatic, actuators can fail. Another possible problem is a leak in one of the connections to the heater core; this may first be noticeable by smell. Glycol may leak directly into the car, causing wet upholstery or carpeting. Electrolysis can cause excessive corrosion leading to the heater core rupturing. Coolant will spray directly into the passenger compartment followed with white colored smoke, a significant driving hazard; because the heater core is located under the dashboard inside of the vehicle and is enclosed in the ventilation system's ducting, servicing it requires disassembling a large part of the dashboard, which can be labour-intensive and therefore expensive. Since the heater core relies on the coolant's heat to warm the cabin air up, it won't begin working until the engine's coolant warms up enough; this problem can be resolved by equipping the vehicle with an auxiliary heating system, which can either use electricity or burn the vehicle's fuel in order to bring the engine's coolant to operating tempera
The Toyota Prius is a full hybrid electric automobile developed by Toyota and manufactured by the company since 1997. Offered as a 4-door sedan, it has been produced only as a 5-door liftback since 2003; the United States Environmental Protection Agency and California Air Resources Board rate the Prius as among the cleanest vehicles sold in the United States, based on smog-forming emissions. The 2018 model year Prius Eco ranks as the second most fuel efficient gasoline-powered car available in the US without plug-in capability, following the Hyundai Ioniq "Blue"; the Prius first went on sale in Japan and other countries in 1997, was available at all four Toyota Japan dealership chains, making it the first mass-produced hybrid vehicle. It was subsequently introduced worldwide in 2000; the Prius is sold with Japan and the United States being its largest markets. Global cumulative Prius liftback sales reached the milestone 1 million vehicle mark in May 2008, 2 million in September 2010, passed the 3 million mark in June 2013.
Cumulative sales of one million were achieved in the U. S. by early April 2011, Japan reached the 1 million mark in August 2011. As of January 2017, the Prius liftback is the world's top selling hybrid car with 4 million units sold. In 2011, Toyota expanded the Prius family to include the Prius v, an extended hatchback, the Prius c, a subcompact hatchback; the production version of the Prius plug-in hybrid was released in 2012. The second generation of the plug-in variant, the Prius Prime, was released in the U. S. in November 2016. The Prime achieved the highest miles per gallon equivalent rating in all-electric mode of any vehicle rated by EPA with an internal combustion engine. Global sales of the Prius c variant passed the one million mark during the first half of 2015; the Prius family totaled global cumulative sales of 6.1 million units in January 2017, representing 61% of the 10 million hybrids sold worldwide by Toyota since 1997. Prius is a Latin word meaning "first", "original", "superior" or "to go before".
In February 2011, Toyota USA asked the US public to decide on what the most proper plural form of Prius should be, with choices including Prien, Prium, Prius, or Priuses. The company announced on 20 February that "Prii" was the most popular choice, the new official plural designation in the US. In Latin prius is the neuter singular of the comparative form of an adjective with only comparative and superlative; as with all neuter words, the Latin plural is priora, but that brand name was used by the Lada Priora in 2007. Despite the "official" plural form used by Toyota USA, "Priuses" is used in English. Beginning in September 2011, Toyota USA began using the following names to differentiate the original Prius from some newer members of the Prius family: the standard Prius became the Prius Liftback, the Prius v, the Prius Plug-in Hybrid, the Prius c. In 1995, Toyota debuted a hybrid concept car at the Tokyo Motor Show, with testing following a year later; the first Prius, model NHW10, went on sale on 10 December 1997.
The first generation Prius was available only in Japan, though it has been imported to at least the United States, United Kingdom and New Zealand. The first generation Prius, at its launch, became the world's first mass-produced gasoline-electric hybrid car. At its introduction in 1997, it won the Car of the Year Japan Award, in 1998, it won the Automotive Researchers' and Journalists' Conference Car of the Year award in Japan. Production commenced in December 1997 at the Takaoka plant in Toyota, ending in February 2000 after cumulative production of 37,425 vehicles; the NHW10 Prius styling originated from California designers, who were selected over competing designs from other Toyota design studios. The Prius NHW11 was the first Prius sold by Toyota outside of Japan, with sales in limited numbers beginning in the year 2000 in Asia, America and Australia. In the United States, the Prius was marketed between the larger Camry; the published retail price of the car was US$19,995. European sales began in September 2000.
The official launch of the Prius in Australia occurred at the October 2001 Sydney Motor Show, although sales were slow until the NHW20 model arrived. Toyota sold about 123,000 first generation Priuses. Production of the NHW11 model commenced in May 2000 at the Motomachi plant in the same area, continued until XW10 manufacture ended in June 2003 after 33,411 NHW11 vehicles had been produced; the vehicle was the second mass-produced hybrid on the American market, after the two-seat Honda Insight. The NHW11 Prius became more powerful to satisfy the higher speeds and longer distances that Americans drive. Air conditioning and electric power steering were standard equipment. While the larger Prius could seat five, its battery pack restricted cargo space; the Prius was offered in US in three trim packages: Standard and Touring. The US EPA classified the car with an air pollution score of 3 out of 10 as an Ultra Low Emission Vehicle. Prius owners were eligible for up to a US$2,000 federal tax deduction from their gross income.
Toyota executives stated that with the Prius NHW10 model, the company had been losing money on each Prius sold, with the NHW11 it was now breaking even. Presented at the April 2003 New York International Auto Show, for the 2004 US model year, the NHW20 Prius was a complete redesign, it became a compact liftback, sized between the Corolla and the Camry, with redistributed mechanical and interior
In an internal combustion engine, the cylinder head sits above the cylinders on top of the cylinder block. It closes in the top of the cylinder; this joint is sealed by a head gasket. In most engines, the head provides space for the passages that feed air and fuel to the cylinder, that allow the exhaust to escape; the head can be a place to mount the valves, spark plugs, fuel injectors. In a flathead or sidevalve engine, the mechanical parts of the valve train are all contained within the block, a'poultice head' may be used, a simple metal plate bolted to the top of the block. Keeping all moving parts within the block has an advantage for physically large engines in that the camshaft drive gear is small and so suffers less from the effects of thermal expansion in the cylinder block. With a chain drive to an overhead camshaft, the extra length of chain needed for an overhead cam design could give trouble from wear and slop in the chain without frequent maintenance. Early sidevalve engines were in use at a time of simple fuel chemistry, low octane ratings and so required low compression ratios.
This made their combustion chamber design less critical and there was less need to design their ports and airflow carefully. One difficulty experienced at this time was that the low compression ratio implied a low expansion ratio during the power stroke. Exhaust gases were thus still hot, hotter than a contemporary engine, this led to frequent trouble with burnt exhaust valves. A major improvement to the sidevalve engine was the advent of Ricardo's turbulent head design; this reduced the space within the combustion chamber and the ports, but by careful thought about the airflow paths within them it allowed a more efficient flow in and out of the chamber. Most it used turbulence within the chamber to mix the fuel and air mixture. This, of itself, allowed the use of higher compression ratios and more efficient engine operation; the limit on sidevalve performance is not the gas flow through the valves, but rather the shape of the combustion chamber. With high speed engines and high compression, the limiting difficulty becomes that of achieving complete and efficient combustion, whilst avoiding the problems of unwanted pre-detonation.
The shape of a sidevalve combustion chamber, being wider than the cylinder to reach the valve ports, conflicts with achieving both an ideal shape for combustion and the small volume needed for high compression. Modern, efficient engines thus tend towards the pent roof or hemi designs, where the valves are brought close in to the centre of the space. Where fuel quality is low and octane rating is poor, compression ratios will be restricted. In these cases, the sidevalve engine still has much to offer. In the case of the developed IOE engine for a market with poor fuels, engines such as Rolls-Royce B series or the Land-Rover use a complicated arrangement of inclined valves, a cylinder head line at an angle to the bore and corresponding angled pistons to provide a compact combustion chamber approaching the near-hemispherical ideal; such engines remained in production into the 1990s, only being replaced when the fuels available'in the field' became more to be diesel than petrol. Internally, the cylinder head has passages called ports or tracts for the fuel/air mixture to travel to the inlet valves from the intake manifold, for exhaust gases to travel from the exhaust valves to the exhaust manifold.
In a water-cooled engine, the cylinder head contains integral ducts and passages for the engines' coolant—usually a mixture of water and antifreeze—to facilitate the transfer of excess heat away from the head, therefore the engine in general. In the overhead valve design, the cylinder head contains the poppet valves and the spark plugs, along with tracts or'ports' for the inlet and exhaust gases; the operation of the valves is initiated by the engine's camshaft, sited within the cylinder block, its moment of operation is transmitted to the valves' pushrods, rocker arms mounted on a rocker shaft—the rocker arms and shaft being located within the cylinder head. In the overhead camshaft design, the cylinder head contains the valves, spark plugs and inlet/exhaust tracts just like the OHV engine, but the camshaft is now contained within the cylinder head; the camshaft may be seated centrally between each offset row of inlet and exhaust valves, still utilizing rocker arms, or the camshaft may be seated directly above the valves eliminating the rocker arms and utilizing'bucket' tappets.
The number of cylinder heads in an engine is a function of the engine configuration. All inline engines today use a single cylinder head that serves all the cylinders. A V engine has two cylinder heads, one for each cylinder bank of the'V'. For a few compact'narrow angle' V engines, such as the Volkswagen VR6, the angle between the cylinder banks is so narrow that it uses a single head spanning the two banks. A flat engine has two heads. Most radial engines have one head for each cylinder, although this is of the monobloc form wherein the head is made as an integral part of the cylinder; this is common for motorcycles, such head/cylinder components are referred-to as barrels. Some engines medium- and large-capacity diesel engines built for industrial, power generation, heavy traction purposes have individual cylinder heads for each cylinder; this reduces repair costs as a single failed head on a
Electric heating is a process in which electrical energy is converted to heat energy. Common applications include space heating, water heating and industrial processes. An electric heater is an electrical device; the heating element inside every electric heater is an electrical resistor, 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. A warning that these can go to high temperatures and create excruciating burns Alternatively, a heat pump uses an electric motor to drive a refrigeration cycle, that draws heat energy from a source such as the ground or outside air and directs that heat into the space to be warmed; some systems can be reversed so that the interior space is cooled and the warm air is discharged outside or into the ground. Space heating is used to warm the interiors of buildings. Space heaters are useful in places, such as in laboratories.
Several methods of electric space heating are used. Electric radiant heating uses heating elements; the element is packaged inside a glass envelope resembling a light bulb and with a reflector to direct the energy output away from the body of the heater. The element emits infrared radiation that travels through air or space until it hits an absorbing surface, where it is converted to heat and reflected; this heat directly warms objects in the room, rather than warming the air. This style of heater is useful in areas through which unheated air flows, they are ideal for basements and garages where spot heating is desired. More they are an excellent choice for task-specific heating. Radiant heaters operate silently and present the greatest potential danger of ignition of nearby furnishings due to the focused intensity of their output and lack of overheat protection. In the United Kingdom, these appliances are sometimes called electric fires, because they were used to replace open fires; the active medium of the heater depicted in this section is a coil of nichrome resistance wire inside a fused silica tube, open to the atmosphere at the ends, although models exist where the fused silica is sealed at the ends and the resistance alloy is not nichrome.
In a convection heater, the heating element heats the air in contact with it by thermal conduction. Hot air is less dense than cool air, so it rises due to buoyancy, allowing more cool air to flow in to take its place; this sets up a convection current of hot air that rises from the heater, heats up the surrounding space and repeats the cycle. These heaters are sometimes filled with oil, they are ideally suited for heating a closed space. They operate silently and have a lower risk of ignition hazard if they make unintended contact with furnishings compared to radiant electric heaters. A fan heater called a forced convection heater, is a kind of convection heater that includes an electric fan to speed up the airflow, they operate with considerable noise caused by the fan. They have a moderate risk of ignition hazard, their advantage is that they are more compact than heaters that use natural convection and are cost-efficient for portable and small room heating systems. A storage heating system takes advantage of cheaper electricity prices, sold during low demand periods such as overnight.
In the United Kingdom, this is branded as Economy 7. The storage heater stores heat in clay bricks releases it during the day when required. Newer storage heaters are able to be used with various tariffs. Whilst they can still be used with economy 7, they can be used with day-time tariffs; this is due to the modern design features. Alongside new designs the use of a thermostat or sensor has improved the efficiency of the storage heater. A thermostat or sensor is able to read the temperature of the room, change the output of the heater accordingly. Water can be used as a heat-storage medium. An electric underfloor heating system has heating cables embedded in the floor. Current flows through a conductive heating material, supplied either directly from the line voltage or at low voltage from a transformer; the heated cables warm the flooring by direct conduction and will switch off once it reaches the temperature set by the floor thermostat. A warmer floor surface radiates heat to colder surrounding surfaces which absorb heat and reflects all non absorbed heat to yet other still cooler surfaces.
The cycle of radiation and reflection starts and slows down nearing set point temperatures and ceases to take place once equilibrium is reached all-round. A floor thermostat or a room thermostat or combination controls the floor on/off. In the process of radiant heating a thin layer of air, in touch with the warmed surfaces absorbs some heat and this creates a little convection. Contrary to belief people are not heated by this warmed circulating air or convection but are heated by the direct radiation of the source and reflection of its surrounds. Comfort is reached at lower air temperature due to eliminating circulating air. Radiant heating experiences highest comfort levels as people's own energy is in balance with its surrounds. Compared to convection heating system based on academic research the air temperatures may be lowered by up to 3