The use of electric water heaters is the most convenient way to solve the problem of lack of hot water supply in an apartment or country house.
Video review - Capacitive water heater.
According to the method of heating water, electric water heaters are divided into two groups:
The use of instantaneous water heaters in which cold water, passing through pipe with heating element, comes out of it already hot, somewhat problematic. First of all, because of the power they consume. This is about 5-8 kW. Not every home's wiring can withstand such power.
It will be much more rational to use electric water heaters of capacitive or storage type. There is a wide range of such water heaters, the capacity of which ranges from 5 to 150 liters.
Just like a flow-type water heater, it has a heating element (heating element). The heating element heats the water to the desired temperature and turns off. When the temperature of the heated water decreases slightly, the heating element turns on again and heats the cooled water. In order to reduce heat loss between the outer casing and the container (tank), a thermal insulation layer of hard foam was created.
An important factor in choosing a capacitive water heater is the fact that the power of such a device is in the region 2 kW. Homeowners won't have to worry about wiring. Water is heated slowly, over several hours, but with such a gentle mode of use, energy consumption becomes significantly less.
Before buying a cylinder water heater, you should decide what volume hot water necessary for use in this home. Accordingly, the more water you need, the larger the capacity water heater you should buy. Because, installing a water heater small volume, the owners will force their device to work without rest, which will increase electricity consumption and significant wear of the water heating elements.
If there are two or more water risers in the home, it would be more advisable to install two or even several water heaters with different tank capacities. For example, in the kitchen, where water consumption is significantly less than on the riser in the bathroom, it is worth installing DHW water heater with a volume of 10 to 30 liters. But when installing a water heater for a bathroom, you need to consider how many people will use it hot water and how much of it will be required for this. For a large family, a tank water heater with a tank volume of 80 to 150 liters or more is best suited.
A little about the design of a cylinder water heater
Basically, the inner surface of most electric water heaters is made of steel coated with a layer of protective enamel. That's enough durable material with good anti-corrosion properties, non-toxic, resistant to chemicals. Installed inside the tank anti-corrosion anode, increasing the service life of metal parts.
In regions with hard water there is a possibility of rapid formation limescale inside the tank. To avoid this unpleasant phenomenon, before installing a capacitive water heater, you should equip the water supply unit with filtering units. If this is not possible, periodically clean the tank from lime deposits.
Capacitive electric water heaters
To create reserves of hot water and use it for various needs There are mainly 2 types of devices: electric capacitive water heaters and gas. The former are used where there are no gas mains nearby, but electrical networks have been laid. Despite the fact that the cost of hot water heated in gas boiler, 3-5 times cheaper than heated in an electric capacitive heater, this is often necessary, since in many cases without hot water it is impossible to carry out most technological processes, if this is production, or just comfortable to exist if these are household buildings and structures.
The principle of operation of an electric water heater is to transfer heat generated when passing through a heating element placed in a container of water, electric current. The heating element transfers this heat to the surrounding water by conduction (contact). The temperature of the water in a cylinder water heater depends on its power: the greater the power, the faster the water heats up and the larger its volume can be heated per unit time.
Thus, capacitive electric water heaters are one of the simplest in their design and principle of operation available in terms of preparation for use (you only need electrical outlet), but quite expensive in terms of the cost of heating a unit volume of water.
Global trends in the field engineering communications In recent decades, they have increasingly gravitated towards maximum decentralization. Preparing everything needed for comfortable life or full production process directly at the point of consumption is an important component of resource-saving environmental management. As an energy carrier, the most convenient option is electricity. The advantages of electric water heating include:
- accessibility - electricity is now supplied to almost every building, including remote villages and summer country houses;
- simplicity - electricity has already become such a familiar attribute of our everyday life that the user will not need any new skills to operate the new electrical appliance;
- environmental friendliness - there are now quite fierce debates about the environmental purity of electricity, because, indeed, during the production of electricity, damage to the environment is still caused, but the meaning of environmental friendliness of electricity consumption is that air pollution does not occur in a metropolis, where the air is already heavily polluted , and at a distance from it;
- safety - installation of a household electric storage water heater usually does not require any additional permissions, installation and operation of a working boiler does not pose a threat to the user’s life, its power does not create additional excessive load on the general house electrical network, and the water heater requires virtually no maintenance, and safety precautions are no more complicated than when heating an electric kettle.
For individual water consumption, water heaters designed for wall mounting, capacity up to 200 l. Domestic hot water is usually required less than it might seem. After all, water in a container can be heated to much higher temperatures than required, and then mixed with cold water. It is convenient to make any calculations for a capacitive water heater using general formulas(1) and (2):
Q = cμmix(tmix - tcold), (1)
where Q is the energy that must be expended to heat water, J; c is the specific heat capacity of water, which at 10 °C is equal to 4.192 kJ/(kg⋅°C); μmix—mass of heated water, kg; tmix is the required temperature of heated water; tcold is the temperature of the heated water. For ease of calculations specific heat capacity water is usually taken equal to 4.2 kJ/(kg⋅°C), and the mass of water μ is numerically equated to its volume V in liters (μ = ρV, where ρ is the density of water, which at 10 °C is equal to 0.99973 g/ cm3); Q = P τ, where P is the required power to heat a given volume of water by the specified temperature difference, kW; τ—heating time, s. Since what is required is not boiling water, but diluted water, we use the expression derived from formula (1):
cμhot(tmix - thot) + cμcold(tmix - tcold) = 0, (3)
where μhot is the mass of hot water in the boiler; thot - temperature of hot water in the boiler. Having carried out calculations using these formulas, taking into account the possibility of setting the value of thot up to 85 ° C, we obtain the required volume, usually within 100 liters. So, a wall-mounted electric capacitive (storage) water heater or boiler is designed to accumulate a certain supply of water, then heat it to a given temperature and maintain it for the purpose of distribution throughout the hot water supply (DHW) system.
Cold water enters the lower part of the water heating tank. To ensure that the stream of incoming water does not mix with the heated water, various diffusers are used to help distribute the water along the bottom of the tank. Heated water rises upward under the influence of convection forces, displacing cold layers. This is how natural water circulation occurs. After heating the entire volume of water to the desired temperature, the heating is turned off.
The water heating tank is made of steel or stainless steel. In the first case, she needs additional protection from corrosion, which is ensured by special enamel. Manufacturers keep the composition of the enamel and the method of its production secret, giving only general information about the name of the technology and the application temperature. For stainless boilers, quality plays an important role welds. Among the manufacturers presented in the review, stainless steel models include Ariston (ABS Platinum), Timberk (FS, RS), Thermex (Flat, Diamond).
Ariston uses argon-arc welding of seams with a tungsten electrode using the Micro Plasma TIG (Tungsten Inert Gas) system. Argon practically does not enter into chemical interactions with molten metal and other gases in the arc combustion zone. Being 38% heavier than air, argon displaces it from the welding zone and reliably isolates the weld pool from contact with the atmosphere. Thermex chose Japanese technology welding of G.5 stainless steel, where welding is performed with an electron beam in a vacuum field.
This welding is most widespread in the aerospace industry, where quality and reliability play a key role. G.5 welding technology does not disturb the structure of stainless steel and retains alloying additives, which preserves high degree resistance of welded seams of water heaters to corrosion. There are also so-called “non-pressure models” on the market, in which the water heating tank is made of plastic.
E The operation of such a water heater imposes certain restrictions on operating parameters. In particular, they can only be used with special water dispensing fittings and only for one water dispensing point. The advantages of such tanks include the absence of corrosion and low weight. The water heating tank is usually located vertically and has a round or square outer section of the lining.
But some manufacturers include in their range narrow (Ariston, AEG, Stiebel Eltron, Nibe, Thermex), flat (Gorenje, Austria Email, Ariston) and even horizontal models (Nibe, Timberk, Gorenje, Ariston) for installation in limited space. Heating is carried out using an electric heating element located in the lower part of the container. The filling and water intake fittings are also located there.
In horizontal and universal tanks, the heating element is sometimes inserted from the side, but this design solution is less preferable because it does not correspond to the direction of natural convection, so an underheating zone may appear in the depths of the tank, where bacteria will begin to multiply. There can be one or several heating elements. In the latter case, it is possible to activate the accelerated heating option, allowing a one-time increase in power heating element(Ariston, Thermex).
In previous years design heating group in all types wall-mounted boilers was “wet”, that is, the heating element and the tube with the temperature sensor were always located inside the tank itself. This imposed certain restrictions on the quality of water, in particular, its hardness. Because the temperature of the heating element is much higher than the temperature environment, scale is deposited on it first.
And replacement or maintenance of the heating element required complete emptying of the boiler. Now some manufacturers use a “dry heating element” in their tanks, located under the bottom of the water heating tank, which can be removed at any time. Some modern water heaters are equipped with a digital display with electronic control of water temperature, even with programming capabilities (Ariston, Gorenje, Thermex). The color of the water heating tank is usually white. But it’s not at all necessary. The market is actively conquered by boiler models in black and metallic colors (Timberk, Gorenje, Thermex).
Equipment
The price includes the delivery set: thermal insulation in a practical casing made of PVC or ABS plastic, one or more heating elements(Austria, Poland). You can also purchase additional compatible equipment to equip the water heater. The price list is available at the link: additional equipment ›.
The thermal insulation that water heaters are equipped with serves to reduce heat loss and reduce energy consumption to maintain the water temperature inside the tank at a given level. The water heater is supplied with a casing and thermal insulation in assembled form, with the exception of models with a volume of 4000 liters or more. Thermal insulation, if necessary, can be easily dismantled and installed to carry the device through doors and installation windows. Electrotherm products come with two types of thermal insulation: polyurethane foam in a soft PVC fabric casing or polyester in a hard ABS plastic casing.
Development of custom equipmentBy special order it is possible to produce a water heater of any volume in the range from 600 to 10,000 liters. At your request, consultants will select a sufficient volume and power of the water heater, based on the estimated hot water consumption at the site.
In addition, at the request of the customer, additions and changes can be made to the design of the water heater, for example: changing overall dimensions, changing the location of the pipes, increasing the operating pressure and electrical power.
You can find out more about the development of a custom-made water heater.
Application and features
The Electrotherm 1000 E electric water heater is a thermally insulated sealed tank, the water in which is heated using one or more electric heating elements made of stainless heat-resistant steel. The heating elements are equipped with thermostats and allow you to regulate the water heating temperature. Also, heating elements are equipped with emergency temperature sensors that protect the water heater from overheating. Structurally, the water heater allows you to organize recirculation of hot water in the DHW system.
Industrial electric water heaters are used for hot water supply (DHW) systems of municipal and commercial facilities that require large amounts of hot water: hotels, schools, kindergartens, hypermarkets, sports complexes, factories, etc. Water heaters are used as the main one or as backup source hot water supply.
The performance of electric water heaters depends on their volume and electrical power. The volume of standard electric water heaters of the E series ranges from 600 to 10,000 liters in the standard version. The power of the water heater in standard models ranges from 4.5 to 90 kW. By special order, the volume and power of the water heater can be changed up or down.
The internal tank of the product is made of high-quality AISI 321 stainless steel or high-strength structural steel with ceramic coating and is designed to operate under excessive internal pressure.
HONEST CAPACITY: unlike a number of other manufacturers, in Electrotherm electric water heaters the capacity of the internal tank is not underestimated. This means that in the 1000 E model the actual capacity is 1000 liters. At the same time, models from a number of other manufacturers
(both Russian and European) marked xx1000 may actually have a smaller capacity, for example 700-800 liters. Thus, manufacturers achieve an apparent reduction in the cost of products, although in fact they reduce the real performance of water heaters.
Differences between types of Electrotherm internal tanks
High strength coated structural steel inner tank
The steel thickness is from 3 mm, the internal coating consists of ceramics with special components. The coating reliably protects the internal tank from corrosion and is resistant to deformation. Coated water heaters are used for heating and storage drinking water, water for sanitary needs (showers, laundries, swimming pools, etc.) and water for technical needs, which is confirmed by the corresponding expert opinion.
The outside of the tank is coated with a special paint, which has water-repellent properties and serves to protect the tank from aggressive environmental influences and from external mechanical damage during transportation and connection.
Internal tank made of high-strength structural steel without coatingSteel thickness from 3 mm, containers with a tank made of structural steel are used in closed heating systems as a heat accumulator ( buffer capacity) and in ventilation systems as a refrigeration accumulator. The outside of the tank is coated with a special paint, which has water-repellent properties and serves to protect against external corrosion and external mechanical damage during transportation and connection.
Interesting fact: for external painting, the same manufacturer's coating is used as for Eiffel Tower in Paris and the Golden Gate Bridge in San Francisco.
Stainless steel inner tank
Stainless steel water heaters are used for heating and storing drinking water, water for sanitary needs (showers, laundries, swimming pools, etc.) and water for technical needs. For production, stainless steel of European origin (France, Finland) of AISI 321 grade with the addition of titanium is used. it has better anti-corrosion properties than the traditionally used AISI 304 and AISI 304L steels.
Why is the country of steel production important: the properties of stainless steel are determined by the content of alloying additives (mostly chromium and nickel), which give the steel anti-corrosion properties. In European steel, the content of alloying additives is higher, and the steel has stronger anti-corrosion properties, in comparison with some types of Russian steel, where it is used to reduce the cost. minimum quantity alloying additives at the lower limit of the standard.
Water heaters of all types are tested overpressureEvery manufactured water heater undergoes testing. Test pressure is up to x2 of the nominal operating pressure. This means that water heaters with a working pressure of 6 bar are tested at a pressure of 12 bar, which confirms the exceptional reliability and quality of the equipment
The high reliability of Electrotherm water heaters is due to the careful selection of materials and use welding equipment and original filler materials from leading European concerns.
You can learn more about the advantages of Electrotherm products.
Warm water in the bathroom and kitchen is a must modern life, making it better in every way. But centralized water supply, providing hot water to most residential buildings, does not always meet the criteria for quality service. And in rural areas or in holiday villages the only way to accept hot shower- This is to heat the water yourself.
Convenience and indispensability of electric water heaters
The most obvious way to heat water is with an open fire or an archaic stove. Until recently, a wood-burning boiler, popularly nicknamed titanium, was popular in rural areas.
Wood-burning Titan
But lighting a titanium furnace or boiler is a labor-intensive task, moreover, it requires fuel and time, and which modern man will burden himself with difficulties if he is used to getting warm water simply by opening the tap?
Convenient use of hot water That's why, electric water heaters They are practically irreplaceable sources of hot water in non-gasified regions that do not have reserves of easily accessible fuel.
Residents of city houses also install them, refusing unstable centralized heat supply, which is much better than depending on an unreliable heat energy supplier.
Water heater in a city apartment In addition, electric water heaters are much easier to use, maintain and connect than a gas boiler, which requires a reliable chimney for its operation.
Types of designs of electric water heaters
Water heaters, or as they are popularly called - boilers, differ in two constructive principles, determining their size and energy consumption:
The water in the boiler warms up to the required temperature in a few hours and is consumed as needed.
There are several methods of heating water, developed and introduced into mass production by such “titans” of the water heater industry as “Ariston”, “Bosch”, “Electrolux”, “Thermex”, “AEG”, “Drazice”, “Thermex”, “Titan” .
But unlike the “exotic” methods - microwave and heating water directly with electric current, “classical” heating using a hot spiral remains the most popular.
Heating water using a heating element
When electric current flows through a conductor that has increased resistance (compared to copper, aluminum or iron), according to the well-known Joule-Lenz law, significantly more heat is released than in electrical wiring wires.
Joule-Lenz law This physical regularity made it possible to create heating elements based on nickel and chromium alloys with high temperature melting.
Under no circumstances should water come into contact with the surface of the heated spiral - thermal electrochemical processes will very quickly destroy the material of the spiral.
In addition, direct electrical contact of live surfaces with water will be unsafe for users operating the water heater.
Dangerous voltage on the surface of the water tap Therefore, the heating element spiral is isolated from water masses, enclosing it in a sealed, waterproof structure with good dielectric properties and acceptable thermal conductivity.
Reasons for the popularity of capacitive water heaters
The design solutions of water heaters largely determine the type of heating elements used in them. For example, in instantaneous boilers, the spirals of heaters and pipes through which water circulates form complex system, difficult to repair.
Instantaneous water heater design But it should be noted that instantaneous water heaters do not consume electricity to heat the reserve volume of water.
Heating of water in storage boilers is carried out more simply - the heating element is installed at the bottom of the tank, and can be easily replaced by the owner of the water heater himself, without the involvement of a specialist.
Free access to the heating element storage water heater
Since instantaneous boilers require a fairly large electrical wiring power to quickly heat the water flow, such water heaters for summer cottages or ordinary apartment Not best choice, taking into account what kind of network there is in holiday villages or wiring in apartment buildings.
Therefore, a kind of “titanium” dominating the boiler market is the storage (capacitive) water heater, which is rightfully considered by users to be the best purchase for the ability to constantly use hot water.
Large assortment storage boilers Whatever the type of heating element, it must be electrically safe, because water is an excellent conductor of current. Therefore, manufacturers of heating elements try to protect the conductive coil from water as best as possible.
Appearance tubular heating element for water heater To do this, the heater spiral, together with heat-conducting insulators, is enclosed in a sealed metal tube that transfers heat to the water.
The electrical connection of the heating element is made in the part of the heating element inaccessible to water on contact terminals electrically connected to the coil.
Various designs Heating elements for water heaters Corrosion of storage tanks
One of the most big problems arising during the operation of a storage water heater is corrosion internal surfaces of the tank.
Corrosion occurs due to the presence of dissolved oxygen in water and its elevated temperature. Currents of an electrochemical nature arise in water.
The inner surface of the heater tank is covered with corrosion It is known that positive ions, breaking away from the metal surface, literally reduce the number of molecules, which affects the physical and chemical resistance of the material.
To prevent this from happening, inner surface The water heater tank is covered with enamel, protecting the metal surface from contact with water.
Another way anti-corrosion protection is to use a more active metal (magnesium) as an anode, which will react to the potential differences that arise, giving up its ions to the reaction instead of steel.
Heating element with worn magnesium anode Modern water heaters are equipped software, which monitors the electrical activity of water, and uses an active titanium anode.
Principles for implementing corrosion protection using anodes Because titanium is very resistant chemical element, then it does not release ions into the reaction; instead, a constant electrical voltage is applied to it.
The voltage level on the titanium electrode is determined by the water heater’s software algorithm, which temporarily turns off the voltage and measures the current potential difference in the water.
Control panel of a modern water heater with program control The connection and adjustment of the operation of this electrode is carried out at the factory, and, as a rule, unlike the magnesium rod, which needs to be changed once a year, replacement of the titanium anode is not required during the entire operation of the water heater.
Types and design of heating elements for water heaters
Another problem that causes electric water heaters to fail is corrosion and destruction of the heating element itself due to the accumulation of scale on its surface.
Limescale impairs the heat transfer of heating elements, as a result of which metal tube overheats and burns out. IN this place Current leakage occurs through scale moistened with water.
Breakdown and destruction of the water heater heating element With each heating element switched on, the electrical breakdown increases in size, and its resistance decreases until short circuit onto the hull through the water.
Current leakage through water can pose a threat to human health and life, so boiler manufacturers began to produce water heaters with dry heating elements.
Dry heating element for water heater This heating element has a slightly different design, in which heat is transferred through air gaps in ceramic insulators. The thermal conductivity and water resistance of the heating element is ensured by a steel bulb in contact with water.
Design of a water heater with a dry heating element Regardless of what kind of heater the water heater is equipped with, when connecting it, you must use RCD to protect against possible leaks that could result in electric shock.
Connecting electric water heaters
For self-installation and putting into operation an electric water heater, you must have minimal skills as an electrician and plumber.
The water heater instructions must clearly describe the entire connection process. If the user does not have enough experience working with plumbing equipment, then it is better to delegate this area of work to the appropriate specialist.
Connecting water fittings to the water heater As already mentioned, water heaters, which are usually installed in the bathroom, must be connected to the electrical network using an RCD without fail, in accordance with the PUE standard.
Clause 7.1.48 PUE Electrical wiring must be designed for the power and current consumed by the water heater. Considering that boilers consume significant current, it is better to use a separate electrical wiring line, protected by a separate circuit breaker, to power them.
Most water heaters plug into a regular outlet with a grounding contact. IN in this case The socket must have a high degree of electrical protection - IP4, and have a hinged waterproof cover.
Socket with protective hinged cover IP44 Some high-power water heaters can be connected to the electrical network using connection terminals. The connection diagram and terminal location are indicated on the boiler body and in the user manual.
