Boilers for indirect heating
- Manufacturer: OPEKS
- Volume: 300(l)
- Container material: carbon steel
- Maximum operating pressure: 3, 6, 10 bar
- Maximum working temperature: 95(° C)
- Heat exchanger: upper
- Heat exchanger type: spiral (helical) welded heat exchanger
- Heat transfer surface area: 1.1(m²)
- Insulation: Yes
- Manufacturer: OPEKS
- Volume: 300(l)
- Container material: enamel coated carbon steel
- Maximum operating pressure: 3, 6, 10 bar
- Maximum working temperature: 95(° C)
- Heat exchanger: upper
- Heat exchanger type: spiral (helical) welded heat exchanger
- Heat transfer surface area: 1.1(m²)
- Insulation: Yes
- Manufacturer: OPEKS
- Volume: 300(l)
- Container material: carbon steel
- Maximum operating pressure: 6 bar
- Maximum working temperature: 95(° C)
- Heat exchanger: lower
- Heat exchanger type: spiral (helical) welded heat exchanger
- Heat transfer surface area: 1.6(m²)
- Insulation: Yes
- Manufacturer: OPEKS
- Volume: 300(l)
- Container material: enamel coated carbon steel
- Maximum operating pressure: 3, 6, 10 bar
- Maximum working temperature: 95(° C)
- Heat exchanger: lower
- Heat exchanger type: spiral (helical) welded heat exchanger
- Heat transfer surface area: 1.6(m²)
- Insulation: Yes
- Manufacturer: OPEKS
- Volume: 300(l)
- Container material: stainless steel
- Maximum operating pressure: 3, 6, 10 bar
- Maximum working temperature: 95(° C)
- Heat exchanger: top and bottom
- Heat exchanger type: spiral (helical) welded heat exchanger
- Heat exchanger material: stainless steel
- Heat transfer surface area: 2.7(m²)
- Insulation: Yes
- Manufacturer: OPEKS
- Volume: 300(l)
- Container material: stainless steel
- Maximum operating pressure: 3, 6, 10 bar
- Maximum working temperature: 95(° C)
- Heat exchanger: lower
- Heat exchanger type: spiral (helical) welded heat exchanger
- Heat transfer surface area: 1.6(m²)
- Insulation: Yes
- Manufacturer: OPEKS
- Volume: 300(l)
- Container material: stainless steel
- Maximum operating pressure: 6 bar
- Maximum working temperature: 90(° C)
- Heat exchanger: upper
- Heat exchanger type: spiral (helical) welded heat exchanger
- Heat exchanger material: stainless steel
- Heat transfer surface area: 1.1(m²)
- Insulation: Yes
- Manufacturer: OPEKS
- Volume: 400-700(l)
- Container material: carbon steel
- Maximum operating pressure: 3, 6, 10 bar
- Maximum working temperature: 95(° C)
- Heat exchanger: upper
- Heat exchanger type: spiral (helical) welded heat exchanger
- Heat transfer surface area: 1.1(m²)
- Insulation: Yes
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Indirect heating boiler
An indirect heating boiler (BKN) is a heat-exchange type heat engineering apparatus in which part of the excess thermal energy of a liquid or gaseous heat carrier (often a secondary one) is utilized, which is used to heat cold water, in order to provide hot water supply or water heating. An indirect heat exchange process in such a water heater is called as opposed to direct heating from a heat source, such as an electric heating element, an open flame torch, and others.
Areas of application of indirect heating boilers
The most important area of application of BKN is the utilization (saving) of thermal energy of various technological or technical coolants, the temperature of which must be lowered in the interests of technological processes (ensuring the operability of equipment), or those coolants that are production waste (equipment work). The use of indirect heating boilers is attractive in that with their help it is possible to dispose of in the interests of hot water supply:
- the heat of overheated technological or technical fluids, furnace or exhaust gases wasted in vain for dissipation in the surrounding space;
- excess heat capacity of hot water heating systems.
In addition, indirect heating boilers are widely used in the most modern systems for obtaining cheap thermal energy from the surrounding space, such as heat pumps and solar plants.
BKN device
By its basic design, the indirect heating boiler is one of the options for the implementation of the classic shell-and-tube heat exchanger. In BKN, the outer casing is usually a steel (carbon or stainless steel) boiler tank with the necessary branch pipes, which has additional thermal insulation to retain heat. Cold water is supplied to this container from the cold water supply system, in it it is heated, stored and supplied (consumed) to the hot water supply system. Inside the casing (tank), depending on its volume, there are single-tube coiled coils (one, two, three, etc.) through which a heating coolant circulates (often the same, but hot water, as well as antifreeze, oil etc.), the excess heat energy of which is used (utilized) to heat cold water in the main tank (tank). Of additional equipment, the design of an indirect heating boiler may include:
- thermometers, thermosensors (heat sensors), thermostats - to control the temperature of heat carriers, the operation of transfer pumps, to protect the apparatus from overheating;
- pressure sensors and safety valves - to control operating modes and protect equipment from damage by excessive pressure;
- protective magnesium anode - as an element of passive electrochemical protection of the steel body of the boiler from damage by corrosion;
- an auxiliary electric heating element (TEN) - to ensure that the required temperature is obtained in the hot water supply system in conditions of a lack of heat transfer from the utilized heat carrier (or its complete absence);
- recirculation system (pump) to ensure constant pumping of heated water through the hot water supply system.
Varieties of indirect heating boilers
Indirect heating boilers can be:
- by purpose: for hot water supply, for heating systems, for alternative energy (heat pumps, solar systems, etc.);
- by volume: household (low-volume, conventionally - up to 500 liters) or industrial (large-volume, from 500 liters and more);
- according to the orientation of the heat carrier flows - vertical (have an optimized, most efficient heat exchange, occupy a small working area) or horizontal (have minimal energy consumption for pumping heat carriers (even their transportation by gravity is possible, without the use of pumps);
- by the method of installation - floor-standing, mounted (wall-mounted);
- only with indirect heating (heat exchange), or combined, with an additional direct electric heater (heating element).
Pros and cons of indirect heating boilers
The indisputable advantages of using indirect heating boilers include:
- The use of BKN for the selection (utilization) of thermal energy from technological or secondary heat carriers allows you to save a lot of funds, fuel or electricity to provide hot water supply, and in some cases - and water heating.
- An undoubted advantage is the simplicity and low cost of the BKN design, which is typical for most options for shell-and-tube heat exchangers. Often, the use of BKN allows for very modest money to solve the local problem of hot water supply, without resorting to expensive boiler or electric water heating equipment in the acquisition, installation and operation.
- Due to the relatively large volumes of boiler tanks (tanks) and the high heat capacity of water, as well as the use of effective thermal insulation, it becomes possible not only to utilize thermal energy, but also to accumulate it in significant quantities. Large-volume BKN can be successfully considered as a heat accumulator.
The disadvantages of indirect heating boilers include the unreliability (inconsistency) of the provision of hot water supply, which depends on the operating modes of the heat carrier systems, the thermal energy of which is used (utilized). For example, at the end of the heating period, it becomes impossible to utilize the excess heat capacity of hot water heating systems, at night or in bad weather it is impossible to obtain hot water from a solar plant, etc. To eliminate this disadvantage, additional (duplicate) direct heating systems are introduced into the design of such indirect heating boilers, as a rule - electric heating elements or gas burners. Also, BKN, as a rule, have very significant dimensions. For the conditions of a private house, workshop or office, this means that it requires at least a separate room for its placement.
Technical characteristics for the selection (selection) of BKN
When choosing (selecting) an indirect heating boiler for your industrial enterprise, workshop, local boiler room, house or apartment, you should be guided (take into account) its main technical characteristics. These characteristics include:
- the volume of the tank, which determines the possibilities for the consumption (one-time, long-term) of the hot water supply system;
- the nature of the heating medium: water, oil, gas, etc .;
- heat exchange area (coil), which is the basis for calculating the utilized heat power;
- flow area and hydraulic resistance of the coil system, for calculating the thermal head (flow rate) and energy consumption for pumping the medium;
- maximum working temperature (heating) of BKN;
- maximum working pressure in systems: heating medium (in the coil) and hot water supply (in the tank);
- dimensions and installation method (vertical, horizontal);
- stability of providing hot water supply only by indirect heating (whether an additional electric heating element is needed or not).
Possible schemes for connecting indirect heating boilers
At industrial enterprises, heating engineers who are familiar with the theory and practice of arranging various heating circuits are engaged in connecting the BKN. At the same time, for the constant supply of a private house, office or workshop with hot water, there are generally accepted schemes for connecting the BKN to single-circuit, and even double-circuit hot water boilers of water heating systems (gas, electric, solid fuel), as well as to heat generating circuits of alternative energy devices (heat pumps or solar plants). These generally accepted schemes include:
1.with the use of a three-way valve, when the temperature sensor controls the water temperature in the BKN, and when it drops to a critical value, switches the three-position valve to take hot water from the hot water heating system to heat water in the BKN tank.
2. Connecting BKN to a thermogenerator (boiler) in the same circuit with water heating. Such a scheme requires the introduction of a recirculation loop with a pump into it.
3. Scheme with two separate circulation pumps - for BKN and water heating. In this embodiment, the main role is played by the BKN circuit, therefore the pump that serves it must be installed in front of the pump for the water heating system.
4. Diagram with a hydraulic arrow. It is used in more complex systems, where, along with heating radiators and BKN, secondary circuits and other heat consumers are used - underfloor heating loops, heated towel rails, etc.
Benefits of boilers from OPEKS Energosystems
OPEKS Energosystems has a wealth of experience in the industrial production of various heat exchange equipment for various purposes, as well as a generally recognized authority and business reputation in the industry. When buying OPEKS indirect heating boilers, you can be 100% sure that you are not purchasing a dubious handicraft device, but a product of real industrial quality that has passed all the necessary stages and procedures of technical control. You should be aware that OPEKS heat exchange equipment meets modern industry standards and has all the necessary quality certificates.
BKN produced by OPEKS are made only of high-quality corrosion-resistant materials, their design and strength characteristics strictly correspond to the design operating conditions. A wide range of standard designs of BKN OPEKS allows you to choose an inexpensive serial device, both industrial and household class, for almost any needs and parameters.