Heating device, whose operation is based on induction heating, induction heaters are called. They are used both in industry and in everyday life, and in the industry of their use value can not be overestimated.
Consider these devices in more detail.
The apparatus and operation principle of the induction heater
Simplified induction heater consists of three component parts:
- an AC generator (1);
- an inductor (2);
- core (3).
The coil consisting of a certain predetermined number of turns of the conductor sectional area is placed a conductive (metal, graphite) shaft without direct contact with it, whereupon the coils contacts the alternator is fed voltage. Around the coil windings formed by the electromagnetic field, under the influence of which the rod eddy currents Foucault core warming. Thus, heat transfer to the core is absent, the heat generated by them alone under the influence of stray currents in it and can be transmitted by means of a coolant. The temperature of the rod increases not simultaneously throughout the bulk and surface layers from the center, depending on the thermal conductivity of the core material. Thus, increasing the AC frequency induction heating reduces the depth, but increases its intensity. It deserves special attention is the fact that the coil around the core during operation remains virtually cold.
Intuitively, this process looks like this:
Areas of use
In industry, induction heaters are used to perform these complex processes:
- ultrapure melting metals (produced in the channel - contactless induction furnaces);
- bending large diameter steel pipes;
- perform surface hardening of steel products (building fittings, the details of gear mechanisms of machine tools, etc.);
- heat treating small parts of complex configuration;
In domestic induction heating device is also widely distributed. Fields of application:
- Household autonomous heating system (for villas, apartments, private homes);
- Induction hobs and tiles for the kitchen;
- Crucible furnace small volume for household metal smelting;
- jewelry craft.
Since the main subject of the article - an induction heater, then elaborate on the boiler, the basis of whose works is the idea of inductive heating the coolant.
Induction heater - heating boiler
Since then, as homeowners began to install in their homes self-contained heating system, the issue of efficiency of heating boilers for them remains one of the most important. By this measure, at least, among the devices that generate heat from electricity, induction heating boilers lead. In this capacity they are not comparable with the same parameter of the device, as the Baseboard heater, allows the use of aggregates as the primary heating process smokers a large area.
Induction heating boilers consist of two circuits - the primary (electromagnetic) and secondary (heat exchanger rail). A first circuit composed of a heat generator and a voltage converter with an induction type heater, creates an electromagnetic field, eddy currents and generates heat. The second circuit including a heat exchanger with a piping system, this conveys heat by circulation of the coolant for heating radiators. As the coolant water is used in pure form or with additives.
In addition to these two circuits, the heating system includes automatic responsible for the operation of individual unit components.
Modern induction heating boilers are installed only in closed type heat exchange circuit having a design expansion tank and membrane type pump forced circulation. Using a circulating pump and is forced measure due to the small volume of the coolant heating heat exchanger at a high intensity. The possibility of natural circulation in such a system is excluded - without pump boiling water occur before the beginning of its motion through the pipes.
Important! Induction boiler must always be grounded. In addition, when installing the coolant heating circuit wiring for security system should be installed of plastic pipes or insulate the heating unit from the contour of the steel insert fittings polypropylene.
Induction heating boilers are classified identical by another electric heating units - in power, performance, parameters of consumed electricity. But these devices have a more constructive solution for the classification of electrical parts.
Varieties of induction boilers
The following types of heating boilers induction type, referred to as the principle of action, and by brand:
- SAV - kind and at the same time the trademark of the new generation of boilers from 2.5 to 100 kW, 2007 produced by the Russian company ZAO NPK "INERA";
- WINE - an abbreviation is not only a reduction in the species name of induction devices (vortex induction heaters), but also the name of a patented boiler produced by the Izhevsk "Alternative Energy".
Induction heaters SAV
Operating units SAV not require the use of an inverter is supplied to the inductor current frequency of 50 Hz. The induced electromagnetic field of the primary winding causes formation of vortex flows in the a secondary winding, whose role in the boilers of this type performs portion closed loop pipe coolant. This pipe section - the secondary coil is heated rapidly under the influence of eddy currents and passes coolant heat forcibly circulating in the heating system by a circulation pump.
The apparatus heating system is performed using the radiators or labyrinth manner reminiscent base board heating to increase the total outer surface area (heat transfer) tubes - heating circuit, at least, should not be minimized by mileage.
SAV boilers are manufactured under the voltage 220V and 380V. As the coolant they use water (pure or with additives of the anti) and anti-freeze. Yield unit to full power operation takes about 5-20 minutes (depending on the volume of the coolant), the heater efficiency of such devices is at least 98%. For efficient heating of premises to 30 m. enough power induction device is 2.5 kW, the purchase is complete with automation and control systems will cost about 30 thousand. rub.
WIN-heating units
Boilers of this type are more perfect the principle of action and design, which, of course, affect their value. For work-VIN devices requires inverter - a device increasing the current input frequency. high frequency current causes the formation of a high intensity electromagnetic field, which in turn causes the appearance of more powerful eddy currents in the secondary winding. Furthermore, the heat exchanger and the boiler body made of ferromagnetic alloys having its own magnetic field. The result of all these processes is the high intensity heat exchanger and naturally coolant.
VIN-unit capacity of 3 kW is sufficient for heating 35-40 sq m. (Depending on the climate and quality of thermal insulation of external building structures).
VIN-units because of the higher performance can be used not only in home heating systems, but also for hot water supply. For this purpose, the heating medium circuit incised additional storage tanks, equipped protective automatics, which capacitance depends on the amount of hot points water intake. The hot water tank provided by its circulation system with once-through heat induction heater.
Evaluation of performance-marketing claims
Induction heating boilers credited with many virtues, often - with no arguments. We list these features and will assess the extent to which a statement of fact:
economy
Statement
Electricity consumption induction boilers 20-30% less than other heaters electricity.
Fact
All heating appliances without operating a mechanical operation, 100% of the electric current energy converted into heat, and their efficiency is always lower than 100%, but differs in magnitude among different devices in different conditions. To generate 1 kW of heat energy must be expended than 1 kW of electricity, but much more - depending on the parameters of dispersion medium. Inside the boiler losses, of course, also present - for example, heating coils, since any conductor material has resistance, but these losses remain indoors
Important! Counters old sample (bakelite) fix smaller (1.6 - 1.8 times) the power consumption, than the modern electronic, as they are not designed for accounting of reactive power of induction boilers.
Perhaps this fact and due to the approval of the efficiency of induction of boilers.
Durability
Statement
High reliability and long life of equipment - more than 25 years.
Fact
Indeed, the absence of moving parts eliminates mechanical wear induction boilers. But the heating system with WIN-unit includes a circulating pump, a resource which is much more modest. In addition, the control and automation system includes mechanisms, also consisting of many parts subject to wear.
The core functions of the induction heater in continuous cyclic heating and cooling, thermal strains, which are also a negative factor. Therefore, call a resource induction boilers almost limitless - an exaggeration. However, it really is several times higher TENovyh heaters.
Repeatable performance over the entire service life
Statement
Lack of process scale formation on the inner surface of pipes causes a constant efficiency of the heater and the heat exchanger.
Fact
Scale - a deposition of salts contained in the water (coolant). The amount of these impurities in limited amount of coolant is also limited and small, so the scale effect on the efficiency of the heater is negligible. And in the induction boiler secondary winding is under almost constant exposure to vibration, and scaling does not occur at all. So that statement is true, only exaggerated its importance.
Quiet
Statement
Work induction heating boilers silent, that sets them apart from other electric heaters.
Fact
Statement is true, but - all the boilers at power no noise at work, as in the range of fluctuations of the acoustic waves are not included. Noise can only pump, but you can choose the model of a silent action.
density
Statement
Induction heaters are compact, which is convenient when choosing a place to install them.
Fact
This is true, if not to use cascade induction boilers and intermediate tanks installed at multiple points hot water intake in hot water supply system, since the induction heater - it is by and large a small piece of pipe winding.
Security
Statement
Device security is absolute.
Fact
Absolutely safe electric heaters do not exist. When operating inductive devices there is a possibility of coolant leakage from the system and the electromagnetic field generator to continue its work, and the system is empty pipes will be heated. To prevent such a situation in the construction of the boiler automatic shut-off device is provided, but after all, it can be damaged.
Therefore, induction heaters, outperforming rivals for certain safety criteria are not completely safe.
Disadvantages of induction heaters
- The high cost of the devices.
- Significant weight compactness.
- Availability factor of influence of the electromagnetic field on the body and fixtures.
The last point is a closer look.
The electromagnetic field affects the living organisms around as for products in a microwave oven - warms them at a certain depth, and this can have consequences. The intensity of the exposure field, including man is determined so its indicator as the energy flux density (PFD) that increases with frequency of current supplied to the primary winding. In operation, induction heaters must comply with sanitary standard limit value of the PES, which is installed in SanPin 2.2.4 / 2.1.8.055-96 depends on the duration of exposure field and is, for example, for an 8-hour exposure - 25 mW / cm, one-hour - 200 mW / cm².
In addition, the radiation of the inductor adversely affect the electronics and radio equipment located nearby, interfering with work.
Important! To protect from the effects of electromagnetic fields, it is possible to enclose meshed boiler (1x1, 2x2 mm) of the metal grid (Faraday cage), the boiler is not in contact with the housing and earthed.
operating rules
Safe operation of the induction heating boilers, as well as any other technical device which can perform a number of rules concerning their installation and use after installation:
- Earthing of the boiler is necessary.
- The distance from the device to the wall on each side must be at least 30 cm, from the bottom of the boiler to the floor - 80 cm, from its upper point to a ceiling - 80 cm.
- Induction heaters are installed only in a closed circuit with an expansion tank membrane.
- The system must include a safety block device (pressure gauge, a vent excess pressure relief valve, the automatic shut down system response when overheated).
Review of well-known manufacturers
- Edison - induction type heaters capacity from 4.7 to 500 kW produced by the Novosibirsk "SibTehnoMash" for domestic and industrial use;
- Miratron - Russian producers NPK Miratron induction heating equipment for residential use, feature advanced design that allows to use the equipment without compromising interior premises;
- Teco-House - induction heating boilers with a unique control system, manufactured by the Ukrainian company of the same name by the EU and the Russian Federation standards.
conclusion
The modern market of boilers for autonomous heating systems installation features hundreds of models of various types of aggregates. Objective criteria of price / quality of each species is different. The choice in favor of induction heating devices in terms of the risk of further disappointment in the purchase of the most intelligent.
