 A trio of propane water heaters. Water heating is a thermodynamic process using an energy source to heat water above its initial temperature. Typical domestic uses of hot water are for cooking, cleaning, bathing, and space heating. In industry both hot water and water heated to steam have many uses. Download high resolution version (1280x853, 188 KB) Wikipedia does not have an article with this exact name. ...
Download high resolution version (1280x853, 188 KB) Wikipedia does not have an article with this exact name. ...
Thermodynamics (from the Greek θεÏμη, therme, meaning heat and δυναμις, dynamis, meaning power) is a branch of physics that studies the effects of changes in temperature, pressure, and volume on physical systems at the macroscopic scale by analyzing the collective motion of their particles using statistics. ...
HVAC may also stand for High-voltage alternating current HVAC is an initialism that stands for heating, ventilation and air-conditioning. This is sometimes referred to as climate control. ...
Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ...
For other uses, see Temperature (disambiguation). ...
For other uses, see Steam (disambiguation). ...
Domestically, water is traditionally heated in vessels known as kettles, cauldrons, pots or coppers. These vessels heat a batch of water but do not produce a continual supply. Appliances for providing a more-or-less constant supply of hot water are variously known as water heaters, boilers, heat exchangers, calorifiers or geysers depending on whether they are heating Potable or non-potable water, in domestic or industrial use, their energy source, and in which part of the world they are found. In domestic installations, potable water heated for uses other than space heating is sometimes known as Domestic Hot Water (DHW). Look up container in Wiktionary, the free dictionary. ...
A kettle is a kitchenware piece. ...
Three-legged iron pots being used to cater for a school-leavers party in Botswana. ...
It has been suggested that this article or section be merged with Cookware and bakeware. ...
A boiler is a closed vessel in which water or other fluid is heated. ...
A heat exchanger is a device built for efficient heat transfer from one fluid to another, whether the fluids are separated by a solid wall so that they never mix, or the fluids are directly contacted. ...
Tap water Mineral Water Drinking water is water that is intended to be ingested through drinking by humans. ...
For other uses, see Home (disambiguation). ...
In many countries the most common energy sources for heating water are fossil fuels: natural gas, liquefied petroleum gas, oil or sometimes solid fuels. These fuels may be consumed directly or by the use of electricity (which may derive from any of the above fuels or from nuclear or renewable sources). Alternative energy such as solar energy, heat pumps, hot water heat recycling, and sometimes geothermal heating, may also be used as available, usually in combination with backup systems supplied by gas, oil or electricity. For other uses, see Natural gas (disambiguation). ...
45 kg LPG cylinders Liquefied petroleum gas (also called LPG, LP Gas, or autogas) is a mixture of hydrocarbon gases used as a fuel in heating appliances and vehicles, and increasingly replacing chlorofluorocarbons as an aerosol propellant and a refrigerant to reduce damage to the ozone layer. ...
An oil tanker taking on bunker fuel. ...
Solid fuel is a term given to various types of solid material that provide energy. ...
Electricity (from New Latin Ä“lectricus, amberlike) is a general term for a variety of phenomena resulting from the presence and flow of electric charge. ...
This article is about applications of nuclear fission reactors as power sources. ...
Renewable energy effectively utilizes natural resources such as sunlight, wind, tides and geothermal heat, which are naturally replenished. ...
Solar power describes a number of methods of harnessing energy from the light of the sun. ...
A heat pump is a machine, which moves heat from a low temperature reservoir to a higher temperature reservoir under supply of work. ...
Hot water heat recycling (also known as drain water heat recovery, greywater heat recovery, or sometimes shower water heat recovery) is the use of heat exchanger technology to recover and reuse hot water heat from various activities such as dishwashing, clothes washing and especially showers. ...
Geothermal heating is a method of heating and cooling a building. ...
In some countries district heating is a major source of water heating. This is especially the case in Scandinavia. District heating systems make it possible to supply all of the energy for water heating as well as space heating from waste heat from industries, power plants, incinerators, geothermal heating and central solar heating. The actual heating of the tap water is performed in heat exchangers at the consumers premises. Generally the consumer needs no backup system due to the very high availability of district heating systems. District heating pipe in Tübingen, Germany District heating (less commonly called teleheating) is a system for distributing heat generated in a centralized location for residential and commercial heating requirements. ...
For other uses, see Scandinavia (disambiguation). ...
Space heating is the heating of a space, usually enclosed, such as a house or room. ...
A power station (also power plant) is a facility for the generation of electric power. ...
This article needs cleanup. ...
Geothermal heating is a method of heating and cooling a building. ...
Central solar heating is the provision of central heating and hot water from solar energy by a system in which the water is heated centrally by arrays of solar thermal collectors (central solar heating plants - CSHPs) and distributed through district heating pipe networks (or block heating systems in the case...
A heat exchanger is a device built for efficient heat transfer from one fluid to another, whether the fluids are separated by a solid wall so that they never mix, or the fluids are directly contacted. ...
Types of water heating appliance Water for space heating can be heated by fossil fuels in a boiler. Potable water may be heated in a separate appliance: this is common practice in the USA where warm-air space heating is usually employed.
Gravity system Where a space-heating water boiler is employed the traditional arrangement in the UK is to use boiler-heated ("primary") water to heat ("secondary") water in a cylindrical vessel (usually made of copper) containing potable water supplied from a cold water storage tank, usually in the roof space of the building. This produces a fairly steady supply of DHW at low pressure but usually with a good flow. Water heating appliances in most other parts of the world do not use cold water storage tanks but heat water at pressures close to that of the incoming mains water supply. // A tank is a container, usually for liquids, sometimes for gases. ...
For automobile roofs, see Sunroof. ...
Water pressure is the pressure in any system for supplying water, usually a domestic water system, although the term is used in other contexts as well, such as a municipal water system. ...
Look up flow in Wiktionary, the free dictionary. ...
A municipal water system is a large system of reservoirs and large-scale piping which supplies fresh water, suitable for human consumption, to houses and other residences. ...
Instantaneous water heaters Stand-alone appliances for instantaneously heating water for DHW (Domestic Hot Water) are known in North America as tankless heaters, elsewhere as multipoint heaters, geysers or Ascots. In Australia and New Zealand there was a similar wood fired appliance known as the chip heater. // The chip heater is a single point, tankless, domestic hot water system popular in Australia and New Zealand from c1880s until the 1960s. ...
A common arrangement where hot-water space heating is employed is for the boiler to also heat potable water giving a continuous supply of DHW without any extra equipment required. Appliances capable of supplying both space-heating and DHW are known as combination (or "combi") boilers.
Although instantaneous heaters can give a continuous supply of DHW the rate at which they can produce it is limited by the thermodynamics of heating water from the available fuel supplies.
Storage systems Another popular arrangement where higher flow rates are required (although for limited periods) is to heat water in a pressure vessel capable of withstanding a hydrostatic pressure close to that of the incoming mains supply. (A pressure reducing valve is usually employed to limit the pressure to a safe level for the vessel.) Fluid pressure is the pressure on an object submerged in a fluid, such as water. ...
A pressure reducing valve (PRV) is a device for reducing the input pressure of a gas or liquid to a predetermined output pressure. ...
In North America these vessels are known as tanks and may incorporate a gas or oil burner heating the water directly.
Where hot-water space heating boilers are used DHW cylinders are usually heated indirectly by primary water from the boiler, or by an electric immersion heater (often as backup to the boiler). In the UK these vessels are known as unvented cylinders (or commonly as Megaflos after the brand name of a widely-used model). In the US, when connected to a boiler they are known as indirect-fired water heaters. A trio of propane water heaters. ...
This article is about brands in marketing. ...
Thermodynamics and economics Water enters residences in the US at about 10 °C (50 °F) (varies with latitude and season). Adults generally prefer shower temperatures of 40–49 °C (105–120 °F), requiring the water temperature to be raised about 30 °C (55 °F) or more, if the hot water is later mixed with cold water. The Uniform Plumbing Code reference shower flow rate is 2.5 gpm (gallons per minute); sink and dishwasher usages range from 1–3 gpm. For other uses, see Celsius (disambiguation). ...
For other uses, see Fahrenheit (disambiguation). ...
Natural gas in the U.S. is measured in CCF (100 cubic feet), which is converted to a standardized heat content unit called the therm, equal to 100,000 British thermal units. A BTU is the energy required to raise one pound of water by one degree Fahrenheit. A U.S. gallon of water weighs 8.3 pounds. So, to raise a 40-gallon tank of 55 °F water up to 105 °F would require 40 x 8.3 x (105 − 55) / 100,000 BTU, or approximately 0.17 CCF, at 100% efficiency. A 40,000 BTU (per hour) heater would take 25 minutes to do this, at 100% efficiency. At $1 per therm, the cost of the gas would be about 17 cents. The therm (symbol thm) is a non-SI unit of heat energy. ...
The British thermal unit (BTU or Btu) is a unit of energy used in the Power, Steam Generation and Heating and Air Conditioning industry globally. ...
In comparison, a typical electric water heater has a 4500 watt heating element, which if 100% efficient results in a heating time of about 1.1 hours. Since 16,600 BTU is roughly 4.9 kWh, at 10 cents/kWh the electricity would cost $0.49. Operating a shower at 2.5 gpm and 104 degrees Fahrenheit is equivalent to operating a 13.2 kW appliance[1]. The watt-hour (symbol W·h) is a unit of energy. ...
Energy efficiencies of tank water heaters in residential use can vary greatly, particularly based on manufacturer and model. However, electric heaters tend to be slightly more efficient with recovery efficiency (how efficient energy is transferred to the water) reaching about 98%. Gas fired heaters have maximum recovery efficiencies of only about 86% (the remaining heat is lost with the flue gasses). Overall energy factors can be as low as 80% for electric and 50% for gas systems.[1]
A tankless water heater operating at those same power levels (at 100% efficiency) would be able to supply 1.6 gpm continuously, raising the temperature by 50 °F. The same unit could supply 1.3 gpm while raising the temperature by 60 °F. To be able to handle a full house load of multiple uses (at least 5 gpm) with a centralized tankless water heater would require three to four times this power level — somewhat difficult to achieve with natural gas, and very difficult to achieve with electricity. Many tankless water heaters can use over 100,000 BTU/h during high flow, and so require especially large power supplies.
Unfortunately, it takes a great deal of energy to heat water, as one may experience when attempting to boil a gallon of water on a stove. For this reason, tankless on-demand water heaters need to have a very large energy source to be usable. A wall outlet, by comparison, can only source enough energy to warm a disappointingly small amount of water: about .17 gpm at 40 °C temperature elevation.
Tank-type water heaters In household and commercial usage, most water heaters in North America are of the tank type. Also called storage water heaters, these consist of a cylindrical tank in which water is kept continuously hot and ready for use. Typical sizes for household use range from 75 to 400 litres (20 to 100 U.S. gallons). These may use electricity, natural gas, propane, heating oil, solar, or other energy sources. Natural gas heaters are most popular in the United States and most European countries, since the gas is often conveniently piped throughout cities and towns and currently is the cheapest to use. Compared to tankless heaters, storage water heaters have the advantage of using energy (gas or electricity) at a relatively slow rate, storing the heat for later use. Larger tanks tend to provide hot water with less temperature fluctuation at moderate flow rates. Electricity (from New Latin Ä“lectricus, amberlike) is a general term for a variety of phenomena resulting from the presence and flow of electric charge. ...
For other uses, see Natural gas (disambiguation). ...
Propane is a three-carbon alkane, normally a gas, but compressible to a liquid that is transportable. ...
Heating oil, or burning oil, also known in the United States as No. ...
Solar power describes a number of methods of harnessing energy from the light of the sun. ...
Storage water heaters in the United States and New Zealand are typically vertical, cylindrical tanks, usually standing on the floor or on a platform raised a short distance above the floor. Storage water heater tanks in Spain are typically horizontal. In India, they are mainly vertical. In apartments they can be mounted in the ceiling space over laundry-utility rooms.
In western countries, where ambient temperature is colder, tiny point-of-use electric storage water heaters with capacities ranging from 8 to 32 litres (2 to 6 gallons) are made for installation in kitchen and bath cabinets or on the wall above a sink. They typically use low power heating elements, about 1 kW to 1.5 kW, and can provide hot water long enough for hand washing, or, if plumbed into an existing hot water line, until hot water arrives from a remote high capacity water heater. They are sometimes used when retrofitting a pump and recirculating plumbing in a building is too costly or impractical. Since they maintain water temperature thermostatically, they will supply hot water at extremely low flow rates, unlike tankless heaters.
In tropical countries, like Singapore, India: An ideal storage water heater may vary from 10 L to 35 L Usage of 6 L tanks is not uncommon. Smaller tanks are sufficient as ambient weather and water temperature are moderate.
The inner tank of the Water heater is the single most important feature of a water heater. The best heaters have a copper container. The second most important feature may be the type of heating element. The cartridge elements score over tubular elements.
Insulation and other improvements In general, the more tank insulation the better, since it reduces standby heat loss. Tanks are available with insulation ratings ranging from R-6 to R-24. It may be possible to add an extra insulating blanket or jacket on the outside of a poorly insulated tank to reduce heat loss.[2] The most common type of water heater blanket is fiberglass insulation with a vinyl film on the outside. The insulation is wrapped around the tank and the ends are taped together. It is important that the blanket be the right size for the tank and not block air flow or cover safety and drainage valves, the controls, or block airflow through the exhaust vent, if any. In very humid locations, adding insulation to an already well-insulated tank may cause condensation problems, potentially causing rust, mold, or operational problems. Thermal insulation on the Huygens probe The term thermal insulation can refer to materials used to reduce the rate of heat transfer, or the methods and processes used to reduce heat transfer. ...
R-value is a term predominantly used in the building industry to rate the insulative properties of construction materials and building assemblies. ...
Bundle of fiberglass Fiberglass (also called fibreglass and glass fibre) is material made from extremely fine fibers of glass. ...
Chemical structure of the vinyl functional group. ...
Modern water heaters have PUF (Polyurethane Foam) insulation. In countries where serviceability is very important, PUF capsules are kept between the inner tank and the outer body. Depending upon the insulation efficiency, star rating is given in India.
Other improvements include check valve devices at their inlet and outlet, cycle timers, electronic ignition in the case of fuel-using models, sealed air intake systems in the case of fuel-using models, and pipe insulation. The sealed air-intake system types are sometimes called "band-joist" intake units. "High efficiency" condensing units can convert up to 98% of the energy in the fuel to heating the water. The exhaust gases of combustion are cooled and are mechanically ventilated either through the roof or through an exterior wall. At high combustion efficiencies a drain must be supplied to handle the water condensed out of the combustion products which are primarily carbon dioxide and water vapor. The ignition system of an internal-combustion engine is an important part of the overall engine system that provides for the timely burning of the fuel mixture within the engine. ...
A joist, in architecture and engineering, is one of the supporting bars that run from wall to wall to support a ceiling (or floor). ...
Return inlet (left)Supply outlet (right). ...
This article is about the chemical reaction combustion. ...
In traditional plumbing in the United Kingdom the space-heating boiler is set up to heat a separate hot water cylinder or hot water tank for potable hot water. Such tanks are often fitted with an auxiliary electrical immersion heater for a quick temperature boost. Heat from the space-heating boiler is transferred to the potable water tank by means of a heat exchanger, and the boiler operates at a higher temperature than the potable hot water supply. Most potable water heaters in the United States are completely separate from the space heating units. A plumber wrench for working on pipes and fittings A complex arrangement of rigid steel piping, stop valves regulate flow to various parts of the building. ...
Residential combustion water heaters manufactured since 2003 in the United States have been redesigned to resist ignition of flammable vapors and incorporate a thermal cutoff switch, per ANSI Z21.10.1. The first feature attempts to prevent vapors from flammable liquids and gasses in the vicinity of the heater from being ignited and thus causing a house fire or explosion. The second feature prevents tank overheating due to unusual combustion conditions. These safety requirements were made based on homeowners placing, and sometimes spilling, gasoline and other flammable gases near their water heaters and causing fires. Since most of the new designs incorporate some type of flame arrestor screen, they require monitoring to make sure they don't become clogged with lint or dust, reducing the availability of air for combustion. If the flame arrestor becomes clogged, the thermal cutoff may act to shut down the heater. The American National Standards Institute or ANSI (pronounced an-see) is a nonprofit organization that oversees the development of standards for products, services, processes and systems in the United States. ...
Petrol redirects here. ...
A wetback stove or wetback heater is the name (used in New Zealand at least) for a simple household secondary water-heater using incidental heat. It typically consists of a hot water pipe running behind a fireplace or stove (rather than hot water storage), and has no facility to limit the heating. Modern wetbacks may run the pipe in a more sophisticated design to assist heat-exchange. A trio of propane hot water heaters. ...
Winter (fireplace), tacuinum sanitatis casanatensis (XIV century) A fireplace is an architectural element consisting of a space designed to contain a fire, generally for heating but sometimes also for cooking. ...
A stove is a heat-producing device. ...
A heat exchanger is a device for transferring heat from one fluid to another, where the fluids are separated by a solid wall so that they never mix. ...
Maintenance It is important that a water heater, particularly a combustion type, be properly installed to avoid safety hazards.[3] The area around it must be kept clear. The T&P (Temperature and Pressure) relief valve should not be tested, as it may not stop leaking if you pop it open. Sediment that accumulates in the bottom of the tank should be drained out at least yearly, to maintain heating efficiency and to make the tank last longer.[4] [5] [6] [7]
In the past, tanks were made out of copper and were very corrosion resistant; they could last for decades. Now tanks are made out of steel lined with glass or porcelain.[8] A steel tank can rust and leak. To prevent this, sacrificial anode rods of magnesium or aluminum alloy themselves undergo galvanic corrosion to reduce corrosion of the steel tank. Tanks with longer guarantees have increased anode material — when the anode is used up, the tank will rust. It may be possible to check the anode condition, and replace it if it is wearing out.[9] Modern US water heater tanks last about ten years.[10] The tank should have a tray underneath to contain leaks and channel them into a drain. Simple, battery-powered alarms are available for $10-$30 that alert the homeowner to leaks.[11] All water heaters will eventually leak, so it is important to know where the water supply shutoff valve is located! For other uses, see Copper (disambiguation). ...
For the hazard, see corrosive. ...
A sacrificial anode, or sacrificial rod, is a metallic anode used in an electrochemical process where it is intended to be dissolved to protect other metallic components. ...
General Name, symbol, number magnesium, Mg, 12 Chemical series alkaline earth metals Group, period, block 2, 3, s Appearance silvery white solid at room temp Standard atomic weight 24. ...
Aluminum is a soft and lightweight metal with a dull silvery appearance, due to a thin layer of oxidation that forms quickly when it is exposed to air. ...
An alloy is a homogeneous hybrid of two or more elements, at least one of which is a metal, and where the resulting material has metallic properties. ...
The Galvanic cell, named after Luigi Galvani, consists of two metals connected by an electrolyte which forms a salt bridge between the metals. ...
Diagram of a zinc anode in a galvanic cell. ...
Electric water heaters made with plastic tanks (e.g, polybutylene) are available. Designed with corrosion-free and corrosion-resistant materials, they can conceivably last the life of a dwelling. The only maintenance requirement would be to periodically clean sediments from the bottom of the tank and clean mineral scale off the heating elements.[12]
Electric water heating power load shifting Because tank-type water heaters store heat, electrical water heaters can be a good match for an intelligent electrical power distribution system, heating when the electrical grid load is low and turning off when the load is high. This could be implemented by allowing the power supplier to send load-shedding requests, or by the use of real-time energy pricing. For other uses, see Heat (disambiguation) In physics, heat, symbolized by Q, is energy transferred from one body or system to another due to a difference in temperature. ...
Tankless heaters Tankless water heaters, also called combination or combi boilers, instantaneous, continuous flow, inline, flash, on-demand or instant-on water heaters, are also available and gaining in popularity. These water heaters heat the water as the water flows through the device, and do not retain any water internally except for what is in the heat exchanger coil. Tankless heaters are often installed throughout a household at more than one point-of-use (POU), far from the central water heater, or larger models may still be used to provide all the hot water requirements for an entire house. The chief advantages of tankless water heaters are a continuous flow of hot water and energy savings (as compared to a limited flow of continuously heating hot water from conventional tank water heaters).
Various types and their advantages Point of use tankless water heaters are located right where the water is being used, so the water is almost instantly hot, which saves water. They also save even more energy than centrally installed tankless water heaters because no hot water is left in the pipes after the water is shut off. However, point of use tankless water heaters are usually used in combination with a central water heater since they are usually limited to under 6 litres/minute (1.5 U.S. gallons/minute), as the expense of buying a heater for every kitchen, laundry room, bathroom, or sink can outweigh the money saved in water and energy bills. In addition, point of use water heaters until recently were almost always electrical, and electricity is often substantially more expensive than natural gas. A kitchen is a room used for food preparation and sometimes entertainment. ...
Laundry room A laundry room (also called a utility room) is a room where clothes are washed. ...
A typical American bathroom A bathroom is a room that may have different functions depending on the cultural context. ...
For other uses, see Sink (disambiguation). ...
Electricity (from New Latin Ä“lectricus, amberlike) is a general term for a variety of phenomena resulting from the presence and flow of electric charge. ...
For other uses, see Natural gas (disambiguation). ...
Tankless heaters can ideally be somewhat more efficient than storage water heaters. In both kinds of installation (centralized and POU) the absence of a tank saves energy as conventional water heaters have to reheat the water in the tank as it cools off, called standby loss. With a central water heater of any type, water is wasted waiting for water to heat up because of the cold water in the pipes between the faucet and the water heater. Categories: Stub ...
Tankless water heaters can be divided into two categories: "full on/full off" and "modulated". Full on/full off units do not have a variable power output level; the unit is either on or off. Modulated tankless water heaters base the heat output on the flow of water running through the unit. This is usually done through the use of a 'flow sensor', modulating gas valve, inlet water temperature sensor and an outlet water temperature sensor-choke valve and means that the occupants should receive the same output temperature of water at differing velocities, usually within a close range of ±2 °C. In physics, power (symbol: P) is the rate at which work is performed or energy is transmitted, or the amount of energy required or expended for a given unit of time. ...
For other uses, see Temperature (disambiguation). ...
The high efficiency condensing combination boiler[13] provides both space heating and water heating, an increasingly popular choice in UK houses. In fact, combination boilers now account for over half of all the new domestic boilers installed in Britain.[14]
In certain parts of South America as well as Costa Rica and Puerto Rico, a point of use style water heater commonly referred to as the "Electric Shower Head" is used in many residential and some commercial installations. As the name implies, an electric heating element is incorporated into such shower heads to heat the water. However, many of these units are often poorly installed, often with exposed wiring in wet locations (hence the nickname, suicide shower). [15]
Under current North American conditions, the most cost effective configuration from an operating viewpoint is usually to use a central tankless water heater for most of the house, and install a point of use tankless water heater at any distant faucets or bathrooms. However, this may vary according to how much electricity, gas and water costs in the area, the layout of the house, and how much hot water is used. Only electric tankless water heaters were available at first and they are still used for almost all point of use heaters, but natural gas and propane heaters are now common. When consumers are considering a whole house gas tankless unit, they are advised to look at how the unit functions when raising the water temperature by about 42 °C (75–77 °F). Thus, if they live in a cold weather climate, they are advised to look at the unit's capacity with 3-10 °C (38–50 °F) inlet water temperatures, and find a size that produces approximately 15 litres/minute (4 gpm) even in winter if they have a typical-sized house and desire what is called a 2-appliance heater. This same unit may produce 25-30 litres/minute (6.3–6.9 gpm) in summer with higher inlet temperatures, but there is greater interest in year round production and usability.
Disadvantages Some disadvantages of tankless water heaters include the following.[2] - Presently, installing a tankless system comes at an increased cost, particularly in retro-fit applications. They tend to be particularly expensive in areas such as the US where they are not dominant, compared to the established tank design. Since the water must be heated instantly, tankless water heaters use a very large amount of electricity or gas while they are on. If a storage water heater is being replaced with a tankless one, the size of the electrical wiring or gas pipeline may have to be increased to handle the load and the existing vent pipe may have to be replaced, adding significant expense to the installation. Gas units are efficient but require a large volume of gas when operating at high firing rates. Many tankless units have fully modulating gas valves that can range from as low as 10,000 to over 1,000,000 BTUs. For electrical installations, AWG 10 or 8 wire, corresponding to 10 or 6 mm², is required for most POU heaters at North American voltages. Larger whole house electric units may require up to AWG 2 wire. In gas appliances, both pressure and volume requirements must be met for optimum operation.
- There is usually a short delay between the time when the water flow starts and when the flow detector activates the heating elements. This results in cold water followed quickly by hot water, and these sudden changes are particularly noticeable when a hot water faucet is turned on and off repeatedly.
- A tank water heater tends to heat idle water in the surrounding piping somewhat, through the process of convection. A tankless water heater only heats water upon demand, so all idle water in the piping is cold. Thus there is a more apparent "flow delay" for hot water to reach a distant faucet.
- Since a tankless water heater is inactive when hot water is not being used, they may be incompatible with hot water recirculation systems.
- Tankless water heaters often have minimum flow requirements before the heater is activated, and this can result in a gap between the cold water temperature, and the coolest warm water temperature that can be achieved with a hot and cold water mix.
- Similarly, unlike with a tank heater, the hot water temperature from a tankless heater is inversely proportional to the rate of the water flow -- the faster the flow, the less time the water spends in the heating element being warmed. Mixing hot and cold water to the "right" temperature from a single-lever faucet (say, when taking a shower) takes practice; one might consider installing a temperature compensating valve.
Electrical wiring in general refers to conductors used to carry electricity, and their accessories. ...
The British thermal unit (BTU) is a non-metric unit of energy, used in the United States and, to a certain extent, the UK. The SI unit is the joule (J), which is used by most other countries. ...
American wire gauge (AWG), also known as the Brown and Sharpe wire gauge, is used in the United States and other countries as a standard method of denoting wire diameter, especially for nonferrous, electrically conducting wire. ...
American wire gauge (AWG), also known as the Brown and Sharpe wire gauge, is used in the United States and other countries as a standard method of denoting wire diameter, especially for nonferrous, electrically conducting wire. ...
Convection in the most general terms refers to the movement of currents within fluids (i. ...
Solar water heaters -
 Direct-gain solar heater panels with integral storage tank In some locales, solar powered water heaters are used. Their solar collectors are installed outside dwellings, typically on the roof or nearby. Nearly all models are the direct-gain type, consisting of flat panels in which water circulates. Other types may use dish or trough mirrors to concentrate sunlight on a collector tube filled with water, brine or other heat transfer fluid. A storage tank is placed indoors or out. Circulation is caused by natural convection or by a small electric pump. At night, or when insufficient sunlight is present, circulation through the panel can be stopped by closing a valve and/or stopping the circulating pump, to keep hot water in the storage tank from cooling. Depending on the local climate, freeze protection, as well as prevention of overheating, must be addressed in their design, installation, and operation. Solar hot water refers to water heated by solar energy. ...
ImageMetadata File history File links Download high resolution version (2592x1944, 2254 KB) Solar water heater used in the Cirque de Mafate, Réunion Copyright © 2005 David Monniaux Template:Cc-by-sa-2. ...
ImageMetadata File history File links Download high resolution version (2592x1944, 2254 KB) Solar water heater used in the Cirque de Mafate, Réunion Copyright © 2005 David Monniaux Template:Cc-by-sa-2. ...
Solar power describes a number of methods of harnessing energy from the light of the sun. ...
Convection in the most general terms refers to the movement of currents within fluids (i. ...
Another type of solar water heater is the evacuated tube collector. It is usually mounted on a roof, and has a row of glass tubes containing heat conducting rods, typically copper. The rods act as heating elements in a circulating loop of antifreeze. The captured heat is transferred into the domestic hot water system by a heat exchanger. This design is smaller and more efficient than traditional flat plate collectors, and works well in very cold climates. The evacuated description refers to air having been removed from the glass tubes to create a vacuum. This results in very low heat loss, once the inside coating has absorbed solar radiation. For other uses, see Antifreeze (disambiguation). ...
Geothermal heating In countries like Iceland and New Zealand, and other volcanic regions, water heating may be done using geothermal heating, rather than combustion. Geothermal heating is a method of heating and cooling a building. ...
Water heater safety Water heaters potentially can explode and cause significant damage, injury, or death if certain safety devices are not installed. When the water temperature exceeds 100 °C (212 °F), the water will remain a liquid inside the tank, but when the pressure is released as the water comes out the tap the water will boil, potentially inflicting steam burns. Water above about 88° C (190 °F) will cause third-degree burns on contact. A safety device called a temperature and pressure relief (T&P or TPR) valve, is normally fitted on the top of the water heater to dump water if the temperature or pressure becomes too high. Most plumbing codes require that a discharge pipe be connected to the valve to direct the flow of discharged hot water to a drain, typically a nearby floor drain, or outside the living space. Some building codes will allow for the discharge pipe to terminate in the garage. For other uses, see Celsius (disambiguation). ...
For other uses, see Fahrenheit (disambiguation). ...
This page deals with the type of injury called burns; for other meanings of burn see burn (disambiguation) In medicine, a burn is a type of injury to the skin caused by heat, electricity, chemicals, or radiation (an example of the latter is sunburn). ...
Oxygen Safety Valve A safety valve is a valve mechanism for the automatic release of a gas from a boiler, pressure vessel, or other system when the pressure or temperature exceeds preset limits. ...
If a water heater is installed in a garage, it is recommended, and many codes require, that it be elevated at least 18 inches (0.46 m) above the floor to reduce the potential for fire or explosion due to spillage or leakage of combustible liquids in the garage. Furthermore, some local codes mandate that tank-type heaters in new and retrofit installations be braced to an adjacent wall with a strap to prevent them from tipping over and breaking the water and gas pipes in the event of an earthquake. This article or section does not cite its references or sources. ...
This article is about the natural seismic phenomenon. ...
For older houses where the water heater is part of the space heating boiler, and plumbing codes allow, some plumbers will install a "Watts 210" device in place of a TPR valve. When the device senses that the temperature reaches 99 °C (210 °F), it will shut off the gas supply and prevent further heating. In addition, an expansion tank or exterior pressure relief valve must be installed to prevent pressure buildup in the plumbing from rupturing pipes, valves, or the water heater. Joe Kessler is a plumber! A plumber is a tradesperson who specializes in installing and maintaining systems used for potable (drinking) water, sewage, drainage, venting, heating and air-conditioning, or industrial process plant piping. ...
An expansion tank is a small tank used in closed water heating systems to absorb the waters thermal expansion as it is heated. ...
Scalding is a serious concern with any water heater. Human skin burns quickly at high temperature, e.g., only 60 °C (140 °F), but also at lower temperatures, e.g., 50 °C (120 °F), if the exposure times are sufficient. Older people and children often receive the most serious scalds due to disabilities or slow reaction times. In Australia and elsewhere it is common practice to put a tempering valve on the outlet of the water heater. A tempering valve mixes enough cold water with the hot from the heater to keep the outgoing water temperature fixed, often set to 50 °C. Without a tempering valve, reduction of the water heater's setpoint temperature is the most direct way to reduce scalding. However, for sanitation, hot water is needed. Most residential dishwashing machines, for example, include an electric heating element for increasing the water temperature above that provided by water heaters.
There are two seemingly conflicting safety issues around water heater temperature — the risk of scalding from excessively hot water, and the risk of incubating bacteria colonies, particularly Legionella, in water that is not hot enough to kill them. Both risks are potentially life threatening and are balanced by setting the water heater's thermostat to at least 50 °C (120 °F). The European Guidelines for Control and Prevention of Travel Associated Legionnaires’ Disease recommend that hot water should be stored at 60°C (140 °F) and distributed such that a temperature of at least 50°C and preferably 55°C is achieved within one minute at outlets.[3] If there is a dishwasher without a booster heater, it may require a water temperature within a range of 57 °C (130 °F) to 60 °C (140 °F) for optimum cleaning,[4] in which case tempering valves set to no more than 55°C can be applied to faucets to avoid scalding. (Note: Tank temperatures above 60°C may produce calcium deposits, which could later harbor bacteria, in the water tank. Temperatures above 60°C may also cause gradual erosion of glassware in a dishwasher.) Species Legionella adelaidensis Legionella anisa Legionella beliardensis Legionella birminghamensis Legionella bozemanii Legionella brunensis Legionella busanensis Legionella cherrii Legionella cincinnatiensis Legionella donaldsonii Legionella drancourtii Legionella drozanskii Legionella erythra Legionella fairfieldensis Legionella fallonii Legionella feeleii Legionella geestiana Legionella gratiana Legionella gresilensis Legionella hackeliae Legionella israelensis Legionella jamestowniensis Legionella jordanis Legionella lansingensis Legionella...
References - ^ Consumers' Directory of Certified Efficiency Ratings
- ^ Instantaneous water heaters
- ^ European Guidelines for Control and Prevention of Travel Associated Legionnaires’ Disease. European Working Group for Legionella Infections (2005-01-01). Retrieved on 2008-02-12.
- ^ A Consumer's Guide to Energy Efficiency and Renewable Energy: Lower Water Heating Temperature for Energy Savings. U.S. Department of Energy (2005-09-12). Retrieved on 2007-10-14.
Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ...
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Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ...
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See also An architectural engineer applies the skills of many engineering disciplines to the design, construction, operation, maintenance, and renovation of buildings while paying attention to their impacts on the surrounding environment. ...
A boiler is a closed vessel in which water or other fluid is heated. ...
An electric water boiler, electric water heater, or electric water urn is a consumer electronics small appliance used for boiling water and maintaining it at a constant temperature. ...
For the physical concepts, see conservation of energy and energy efficiency. ...
Hot water heat recycling (also known as drain water heat recovery, greywater heat recovery, or sometimes shower water heat recovery) is the use of heat exchanger technology to recover and reuse hot water heat from various activities such as dishwashing, clothes washing and especially showers. ...
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