A cast iron household radiator
Federal Register Volume 77, Number 58 (Monday, March 26, 2012)Rules and Regulations Pages 6 From the Federal Register Online via the Government Printing Office www.gpo.gov FR Doc No: 2012-4826 Vol. 58 March 26, 2012 Part II Department of Labor - Occupational Safety and Health Administration - 29 CFR 1910, 1915 and 1926 Hazard Communication; Final Rule. Special Inspection Manual: 2018 Edition In extreme natural events such as earthquakes and hurricanes, the most common contributing factor to significant structural damage and building failure is construction that fails to comply with codes, standards. The replacement of a manual heating control with a TRV has been estimated to save at least 280 kilograms (620 lb) of CO 2 per year. They are also considerably cost-efficient, using heat only when needed, and can reduce heating bills by up to 17 percent a year. Radiators and convectors are heat exchangers designed to transfer thermal energy from one medium to another for the purpose of space heating. Denison Olmsted of New Haven, Connecticut, appears to have been the earliest person to use the term 'radiator' to mean a heating appliance in an 1834 patent for a stove with a heat exchanger which then radiated heat.
Heat exchange by built-in bathroom radiator uses hot water flow through the stainless steel pipes seen here to raise the temperature of the ambient air. The radiator depicted here also serves as a towel rack and warmer.
Radiators and convectors are heat exchangers designed to transfer thermal energy from one medium to another for the purpose of space heating.
Denison Olmsted of New Haven, Connecticut, appears to have been the earliest person to use the term 'radiator' to mean a heating appliance in an 1834 patent for a stove with a heat exchanger which then radiated heat. In the patent he wrote that his invention was a peculiar kind of apparatus, which I call a radiator.[1] The heating radiator was invented by Franz San Galli in 1855, a Prussian-born Russian businessman living in St. Petersburg.[2][3] In the late 1800s, companies, such as the American Radiator Company, promoted cast iron radiators over previous fabricated steel designs in order to lower costs and expand the market.
Radiation vs. convection[edit]
In practice, the term radiator refers to any of a number of devices in which a fluid circulates through exposed pipes (often with fins or other means of increasing surface area), notwithstanding that such devices tend to transfer heat mainly by convection and might logically be called convectors.
The terms convection heater or convector refers to a class of devices in which the source of heat is not directly exposed. As domestic safety and the supply from water heaters keeps temperatures relatively low, radiation is inefficient in comparison to convection. Convection heaters also work differently from electric radiators in that they disperse heat differently.[4]
Energy Source[edit]
Hotwater baseboard-style radiator (top) which is covered (left) and opened (right), with inside view (below) showing the aluminium fins which are attached in series to the copper pipe.
Steam[edit]
A cast iron radiator with Single-pipe steam supply
Steam has the advantage of flowing through the pipes under its own pressure without the need for pumping. For this reason, it was adopted earlier, before electric motors and pumps became available. Steam is also far easier to distribute than hot water throughout large, tall buildings like skyscrapers. However, the higher temperatures at which steam systems operate make them inherently less efficient, as unwanted heat loss is inevitably greater.[citation needed]
Steam pipes and radiators are prone to producing banging sounds called steam hammer. The bang is created when some of the steam condenses into water in a horizontal section of the steam piping. Subsequently, steam picks up the water, forms a 'slug' and hurls it at high velocity into a pipe fitting, creating a loud hammering noise and greatly stressing the pipe. This condition is usually caused by a poor condensate drainage strategy and is often caused by buildings settling and the resultant pooling of condensate in pipes and radiators that no longer tilt slightly back towards the boiler.[citation needed]
Hot water[edit]
A hot-water radiator consists of a sealed hollow metal container filled with hot water by gravity feed, a pressure pump, or convection. As it gives out heat, the hot water cools and sinks to the bottom of the radiator and is forced out of a pipe at the other end. Anti-hammer devices are often installed to prevent or minimize knocking in hot water radiator pipes.
Electricity[edit]
Unlike steam or hot water systems which receive heat from a boiler, electric radiators produce heat from electricity at the location of the radiator. This heat may be transferred to a fluid (such as oil) inside the radiator. The oil circulates inside the radiator by convection, which distributes the heat from the heating element to the surface of the radiator. Smaller electric radiators have the advantage of being portable, as they do not need to be connected to pipework. Some electric radiators can also use hot water, this is particularity common for heated towel rails, where the radiator uses hot water when the central heating system is running but switches to electricity when heating the whole building is not required.
Shape and design[edit]
Cast Iron[edit]
Cast iron radiators may be used with hot water or steam systems. Traditional cast iron radiators are no longer common in new construction, replaced mostly with forced hot water baseboard or panel radiators, but they remain available.
Hot-water baseboard[edit]
Hot-water baseboard radiators consist of copper pipes which have aluminium fins to increase their surface area. These conduction boiler systems use conduction to transfer heat from the water into the metal radiators or convectors.
The radiators are designed to heat the air in the room using convection to transfer heat from the radiators to the surrounding air. They do this by drawing cool air in at the bottom, warming the air as it passes over the radiator fins, and discharging the heated air at the top. This sets up convective loops of air movement within a room. If the radiator is blocked either from above or below, this air movement is prevented, and the heater will not work. Baseboard heating systems are sometimes fitted with moveable covers to allow the resident to fine-tune heating by room, much like air registers in a central air system.
Panel radiator[edit]
Panel radiators are welded from flat or corrugated steel panels, and are usually hung from the wall. They are usually used with hot water systems, but electric versions are also available. The panels often have fins attached, which increases the surface area and therefore the amount of heat that can be transferred into the air. Several panels may be stacked together to make one radiator, and the resulting radiator is referred to with a two-digit type number. The first digit is the number of panels, and the second is the number of sets of fins, for example a type 21 radiator has two panels with one set of fins in between. Air flow around the radiator and between the panels is by convection only, and must be unrestricted if the radiator is to reach it's design performance. The heat output of panel radiators is regulated by controlling the flow of hot water, with either a manual or thermostatic valve.
Fan-assisted heat exchanger[edit]
A fan-assisted radiator contains a heat exchanger fed by hot water from the heating system. A thermostatic switch energises an electric fan which blows air over the heat exchanger to circulate it in a room. Its advantages are small relative size and even distribution of heat. Disadvantages are fan noise and the need for both a source of heat and a separate electrical supply.
Underfloor[edit]
In underfloor heating, tubing is placed on the floor throughout the room and later covered with a concrete layer during construction.
Also known as 'radiant heat', underfloor heating uses a network of pipes, tubing or heating cables, buried in or attached beneath a floor to allow heat to rise into the room. Best results are achieved with conductive flooring materials such as tile. The large surface area of such room-sized radiators allows them to be kept just a few degrees above desired room temperature, minimizing convection. Underfloor heating is more expensive in new construction than less efficient systems. It also is generally difficult to retrofit into existing buildings.
The Roman hypocaust employed a similar principle of operation.
Skirting-board heating[edit]
Skirting-board radiators are a form of heating which involves placing radiators inside a skirting board. Hot water is piped though the system, usually taken directly from the central heating system.[5]
See also[edit]
References[edit]
Wikimedia Commons has media related to Radiators. |
- ^Kay, Thornton (14 March 2016). 'A peculiar kind of apparatus, which I call a radiator'. SalvoNEWS. Retrieved 22 December 2016.
- ^Family Sangalli / San Galli
- ^Johnny Acton; Tania Adams; Matt Packer (2006). Origin of Everyday Things. Sterling Publishing Company, Inc. p. 205. ISBN1402743025. Retrieved February 4, 2015.
radiator 1855 invented.
- ^'Electric Radiators vs Convection Heaters'.
- ^'In depth knowledge'. Retrieved 26 August 2014.
Sources[edit]
- 'Operating information on electric radiators'. Laura LNorth01. 2020.
Retrieved from 'https://en.wikipedia.org/w/index.php?title=Radiator_(heating)&oldid=1009817428'
A thermostatic radiator valve on position 2 (15-17 °C).
Section of a thermostatic radiator valve.
A thermostatic radiator valve (TRV) is a self-regulating valve fitted to hot water heating system radiator, to control the temperature of a room by changing the flow of hot water to the radiator.
Functioning[edit]
The classic thermostatic radiator valve contains a plug, typically made of wax (forming a wax motor), which expands or contracts with the surrounding temperature. This plug is connected to a pin which in turn is connected to a valve. The valve gradually closes as the temperature of the surrounding area increases, limiting the amount of hot water entering the radiator. This allows a maximum temperature to be set for each room.
As the valve works by sensing the temperature of the air surrounding it, it is important to ensure that it is not covered by material (such as curtains). If the controller is removed from the valve the valve turns on and the radiator will always be hot.
TRVs should not be installed in the same room where the boiler thermostat is installed. This is because in the case that the TRV set temperature is below the boiler thermostat set temperature, the TRV would shut off the radiator before the latter temperature is reached. The boiler would continue to run in an attempt to reach its thermostat set temperature, potentially heating the rest of the house to uncomfortably high levels if TRVs are not installed in every room. If both TRV and thermostat set temperatures were set equally, unpredictable behaviour may occur with both devices attempting to control the room temperature.
The replacement of a manual heating control with a TRV has been estimated to save at least 280 kilograms (620 lb) of CO2 per year.[1] They are also considerably cost-efficient, using heat only when needed, and can reduce heating bills by up to 17 percent a year.[2]
As of 2012, electronic TRVs are becoming available which use electronic temperature sensing, and frequently contain programmers so that individual radiators may be programmed for different temperatures at different times of the day. Such increased control allows even better energy and CO2 saving.[3]
Temperatures[edit]
Position of most Danfoss heads[4][5] | Position of Caleffi heads[6] | Temperature in °C | Temperature in °F | Recommended use[4][7] |
---|---|---|---|---|
❄ | ❄ | 7 | 44.6 | Frost protection |
1 | 12 | 53.6 | Cellar, stairs | |
1 | 13 | 55.4 | ||
14 | ||||
15 | 59 | Laundry room | ||
2 | 16 | 60.8 | Entrance hall | |
2 | • | 17 | 62.6 | |
• | • | 18 | 64.4 | Bedroom |
• | • | 19 | 66.2 | Kitchen |
3 | 3 | 20 | 68 | Living room |
• | • | 21 | 69.8 | |
• | • | 22 | 71.6 | Bathroom |
4 | • | 23 | 73.4 | |
4 | 24 | 75.2 | ||
25 | ||||
5 | 26 | 78.8 | ||
27 | ||||
5 | 28 | 82.4 |
See also[edit]
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Notes and references[edit]
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- ^Energy Saving Trust (2011), Heating and hot water controls
- ^'Archived copy'. Archived from the original on 2014-03-24. Retrieved 2014-03-24.CS1 maint: archived copy as title (link)
- ^OpenTRV aims to save 50% of space heating energy for typical UK home
- ^ abDanfoss. 'User guide - radiator thermostats'(PDF). Retrieved 19 February 2021.
- ^Danfoss. 'RA 2000 thermostatic sensors datasheet'(PDF). Retrieved 19 February 2021.
- ^Caleffi. 'Thermostatic radiator valves'(PDF). Retrieved 19 February 2021.
- ^Cantonal Energy and Environment Services of French-speaking Switzerland. 'Bien utiliser la vanne thermostatique' (in French). Retrieved 18 September 2016.
Wikimedia Commons has media related to Thermostatic radiator valves. |
Retrieved from 'https://en.wikipedia.org/w/index.php?title=Thermostatic_radiator_valve&oldid=1007683515'