Optimization of engineering and communication systems in the household inevitably leads to the expansion of the functionality of the equipment. This trend is gradually leading to energy savings, simplified installation activities and increased operational ergonomics. A vivid example of combining several functions is an indirect heating water heater . What is this in terms of destination? These are household units-boilers that can simultaneously be used for heating and providing hot water (DHW).
Equipment design
The general device is similar to typical flowing water heaters, but there are many differences due to the features of the principle of operation. With regard to similar features, then they include a plumbing infrastructure with pipes and means of regulation. What is it in an indirect heating water heater? Technically, the set of components of this infrastructure can be represented as follows:
- Capacity (tank containing water). This is usually an enamelled steel tank.
- Heater cover.
- Electrical cover.
- Polyurethane based insulation.
- Tubular heat exchanger.
- Pipes for directing cold and warm water.
- Branch pipe for outflow of hot water.
- Circulation (pipeline). It is mainly used in equipment with large heat exchangers.
- Thermostat with indicators and operating controls.
- Safety block.
Now it is worth considering the design features of indirectly heated boilers. Mostly they are expressed in a water heating system. If gas burners and electric heat sources (heating elements) are used in ordinary instantaneous water heaters and storage tanks of the hot water supply system, then in this case the heat carrier flowing through the coil is used. It is he who carries out the heating of water in the tank from the inside. However, indirect water heaters are also found with heating elements, which can be “wet” or “dry”. That is, in one case, the electric heater is in direct contact with the aqueous medium, and in the second, it is assumed to be placed in a sealed tube that isolates the heater, giving off thermal energy from it to the water outside.
Principle of operation
If direct-flow type water heaters can be considered as autonomous, then indirect-heating boilers are at least dependent on boilers. That is, a bundle is realized in which the boiler equipment acts as a source of thermal energy for an indirect heating water heater - what is this in practical use? It has already been said that the main structural difference of boilers is a tubular heat exchanger in the form of a coil, through which the coolant (water or antifreeze) circulates. It is connected to the boiler through a special tubular line with a circulation pump, due to which the movement of hot liquid is ensured. And already inside the boiler tank, water is heated as a result of heat transfer from the coil. By the way, there are different designs of heat exchangers, which largely determine the heating rate. For example, the “coil-in-coil” system provides fast, uniform heating.
But where does the energy come from for the operation of the circulation pump and the subsequent return of water to the domestic hot water system? Firstly, there are indirect indirect electric water heaters, some of the functions of which are supported by the local 220 V power supply network. Moreover, this does not mean at all that a heating element is necessarily present in such an aggregate. To ensure the operation of the circulation pump and to carry out electric heating are fundamentally different tasks, which require energy costs that are incomparable in volume. Secondly, the operation of pumps, thermostats and automation can be supported by individual power supply circuits - including those associated with boiler equipment. In this case, the boiler acts only as a structural basis for the content of heated water with pipeline channels for its filling and return.
Scopes of boilers
The complexity of the design of a heater with indirect heating leads to its extensive application possibilities. First of all, this is the household segment. In private country houses, boilers are used both for heating and for the organization of domestic hot water. Moreover, it is possible to supply water with several consumption points on different floors at once - the ability to deliver a resource in one volume or another will be determined by the capacity of the installation and auxiliary pumping equipment. In apartments, such devices are mainly used as a means of heating, integrating the design into a central water supply unit. In industry, for technological tasks, indirect indirect storage water heaters with heat pumps are used. At various industries, they are used both in the composition of heating systems and in air conditioning systems.
Types of equipment
The design of the boiler with indirect heating can vary, causing certain options for placement, connection and organization of the work process. To date, the following types of this technique are actively produced:
- Wall mounted unit. As the name implies, the design is designed to be fixed to a vertical surface, which saves space. Typically, wall mounted indirect water heaters are used in apartments. They are notable for their small capacity, modest size and small volume of the tank.
- Floor boiler. From the point of view of technical and operational qualities, this is the opposite of a wall model. Such units have impressive dimensions, contain large-capacity tanks and also require the installation of a special supporting platform for installation. Scope - private households and the industrial sector.
- Recycled boilers. Models with a developed internal piping system and effective support from the circulation pump. This allows for an almost instantaneous supply of hot water to the tap.
- Tank-in-tank models. A special version of an indirect heating cylinder, in which there are two tanks (one in the other). The internal tank contains directly pure water for consumption, and outside it is heated by technical hot water, the temperature of which is maintained from the associated boiler or the heater of the boiler itself. Such a complex device is required to maintain high performance, which allows the installation to work as a instantaneous water heater with a water temperature of about 90-95 ° C.
Main technical and operational characteristics
Without exception, all water heaters are characterized by one list of operating parameters, which primarily include:
- Tank volume. On average, the range extends from 40-60 liters to 1000 liters. Minimum values of the order of 30 liters will be enough to supply hot water to one low-cost consumer - for example, a kitchen appliance. For complex home maintenance, an indirect water heater of 200 liters or more is required.
- Power. This characteristic applies to electric boilers. The average power range varies from 1500 to 3000 watts. Power affects the speed of heating water, taking into account the capacity of the tank.
- Boiler performance. The productivity of a particular unit will directly tell about the heating time, which is expressed in liters of hot water released into the domestic hot water system in 1 hour. In relation to household models, we can talk about a figure of the order of 500-700 l / h. For example, an indirect heating water heater MEGA WE 220.82 with a 220 l tank provides a capacity of 630 l / h, while Ariston NHRE heats 350 l of water in 22 minutes.
Positive feedback on boilers
Specialists generally appreciate the opportunities offered by the indirect heating concept. The implementation of this principle on the example of a water heater saves the user from the mass of technical operations associated with the installation of electrical wiring. In addition, there is a high performance of such systems. With relatively modest operating costs, you can get full support for domestic hot water. This is especially true for cases when the indirect heating water tank is served by a heat exchanger from the boiler without the participation of heating elements. This infrastructure assumes minimal energy consumption, but with a high return of thermal energy. That is, in comparison with electrical equipment, experts note the boiler’s advantage in terms of energy efficiency, while against the background of gas units it will win according to the criteria of safety and service life. Of course, the extent to which these positive operating factors will appear in a particular case depends on the characteristics of the model used.
Negative reviews of boilers
Despite the above-mentioned advantages of indirectly heated water heaters, engineers and designers of communication networks do not advise rushing to purchase this equipment without taking into account its weak points. Not in every case it will be possible to come to terms with its disadvantages:
- Powerful models take up a lot of space, which complicates the operational process and requires the installation of additional devices.
- As price analysis shows, boilers are more expensive than conventional drives, and in some cases boiler equipment.
- Ambiguous reviews regarding the intensity of the indirect heating water heater. What is it from the point of view of the average user? In essence, we are talking about the speed of heating water. The point is not even that on average it is slow when compared with the capabilities of alternative systems. Criticism concerns the instability of heating, which may be due to external operating conditions, microclimate and season.
- Low maintainability. The technical and structural complexity of the equipment does not allow you to repair it yourself, and in some cases to carry out maintenance measures without the participation of a service team.
Consumables for the boiler
When buying a water heater, you should also pay attention to the equipment. It may be incomplete or inappropriate, which in the future will force to additionally purchase some accessories. This applies to plumbing fittings for connection - it is represented by hoses, pipes, fittings, clamps and flanges to ensure tight connections. For the installation of indirect indirect water heaters, it is advisable to provide a special platform with a thermally insulated coating. Factory devices are advantageous in that they make it possible to conveniently carry out the lower trim without invading the flooring structure. It will be useful to provide for a set of spare parts. Experts recommend that you always have a magnesium anode in your household for protection against corrosion and scale, a suitable heat exchanger, valves and protective devices.
Indirect Water Heater Connection
To perform strapping (connection), different types of pipes can be used. If it is necessary to connect to the riser or the central pipeline, metal products are used, and for less critical transitional nodes between the boiler and domestic hot water supply, it is possible to limit oneself to heat-resistant polypropylene. The contours are fixed by plumbing holders and clamps, but without a rigid clamp. As the instructions for indirect heating water heaters note, the possibility of free oscillation should be provided, since if the vibrating equipment works with a hard grip, breakage cannot be avoided. Pipe cutting is carried out using pipes and fittings of a suitable size. By the way, when drawing up a pipe laying scheme, it is desirable to minimize the number of transitional nodes, joints and branches. If it is planned to create a multi-level DHW network with a large number of consumption points, it makes sense to include a collector installation in the system.
Conclusion
The use of boilers can justify itself both in terms of the quality of solving the tasks of hot water supply, and from the point of view of economic feasibility. Both factors depend on how correctly the choice of a particular model was made. For a private house, it is entirely possible to purchase a floor-mounted water heater with indirect storage type storage. The capacity can be 250-350 liters, which is enough to fully cover the needs of a two-story mansion. For a small apartment, you should give preference to a compact model with a wall installation of 60-80 liters. Such a solution will minimize energy costs by stably providing domestic hot water and heating functions in return for centralized maintenance.