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Most often, our houses use a water heating system, i.e. the system where plain water is used as the heat carrier. We are accustomed to water heating and often perceive it as something ordinary that does not require additional attention. However, when installing a water heating system in a house, there are nuances that everyone needs to know. Especially in our age, when the price of heat is growing all the time.
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heat sources
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connection to external heating networks
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individual and alternative sources
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piping system
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natural and pumped circulation
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various types of pipes
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heating appliances
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convectors
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radiators
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thermostat
Heat sources
The heart of any heating system is the heat source. The heat source can be CHPserving the entire area, or boiler room for one or more houses.
The CHP supplies the city with superheated water with parameters not suitable for the heating systems of the building. Therefore, the «adjustment» of the parameters (temperature and pressure drop) occurs in central heating point (CHP)serving a group of buildings, or, if any, in individual heating point (ITP) building. Heat is supplied from the CHPP according to the temperature schedule, i.e. The lower the air temperature outside, the hotter the water must flow into the heating system of the building.
When installing a water heating system, there are some nuances
Connection of the heating system to heat networks can be carried out according to a dependent or independent scheme. When dependency connections superheated water from heating networks is mixed (in a certain proportion) with return water from the heating system, thereby obtaining water with a temperature suitable for the heating system. With this connection, heating points can be equipped with pump mixing plants or water jet elevators. At independent connection superheated water is in contact with the water circuit of the heating system through the walls of the heat exchanger (no mixing of water). For this, water-to-water heat exchangers are used, and the circulation pump provides the necessary pressure.
If your house is not connected to external heating networks serving a group of buildings, then most likely you will need to install boiler required power. The boiler can be gas, electric, run on liquid or solid fuel. The boiler can also work in conjunction with solar celllocated, as a rule, on the roof of the house. The latter, however, directly depends on the climatic conditions of the area and feasibility studies. In Russia, installations using solar energy have not yet been widely used, but despite this, this direction is promising in some regions of our country. The heat source can also be Heat pump.
Piping system
To transfer heat to the premises of the house is used piping system. The design of the system and its type is determined at the design stage. The heating system can be natural circulation water in pipes or artificial (pumping).
In system with natural circulation the movement of water in the pipes occurs due to the difference in the densities of the water in the supply pipeline and the water that has cooled down after passing through the heating devices. Such a system requires a height difference between the upper level of the system and the boiler. To reduce pressure losses in a heating system with natural circulation, the diameters of the pipelines must be made sufficiently large. With natural circulation of water in pipes, only small heating systems (for example, in a private house) can work. More reliable and versatile system with pump circulation. In it, the pressure head, which ensures the movement of water in a closed circuit, is created using an electric circulation pump.
Pipelines of the heating system can be laid in rooms in an open way or “hidden” pipes, for example, in a screed water heated floor. There are different types of pipes for use in heating: metal, metal-plastic, plastic.
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Steel pipes able to withstand high pressure and operate at high temperatures (even with superheated water). The price of steel pipes is lower than that of metal-plastic, plastic and copper pipes. The disadvantages include a large specific gravity, the possibility of corrosion, laboriousness during installation, the need for painting with open laying.
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Metal-plastic pipes (PEX-AL-PEX) are used both in a system with heating devices, and for a water-heated floor. Due to the smoother surface compared to steel pipes, this type of pipe has a low hydraulic resistance, i.e., the pressure loss during the passage of the coolant through them is less than that of steel pipes. Smaller pressure losses make it possible to use circulation pumps of lower power. Metal-plastic pipes can be bent by hand without much effort, while they retain their new shape. The cost of such pipes is higher than the cost of steel and polyethylene (PEX) pipes.
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Maximum application temperature polyethylene (PEX) pipes usually lower than that of metal-plastic ones, therefore they are usually used in a water-heated floor system in which the water temperature does not exceed 40-50aboutC. PEX pipes are usually designed for concealed installation, because there are requirements to exclude exposure to sunlight during operation. Pipes can be bent by hand, while they are not as plastic as metal-plastic ones and after a short time they again take their original shape.
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Copper pipes as well as metal-plastic and polyethylene, they are not subject to corrosion and have low hydraulic resistance. Copper pipes can be used both in a heating system with heaters, and in a «warm floor» system. Their disadvantage can be considered high cost — higher than that of any of the considered types of pipes.
Heating appliances
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From the boiler through the piping system, the coolant enters heater a specific room, where it gives off the amount of heat necessary to maintain the required air temperature. Modern heating devices have a pleasant appearance and good thermal performance. Install the heater most often under the window or against the outer wall. It is worth remembering that when installing decorative screens at the heater, the power of the latter should be increased by about 10%. Heating devices are divided into two large groups: convectors and radiators. During operation, the convector generates a more powerful flow of ascending warm air (convection). The disadvantage of convectors is the difficulty of cleaning the fins of their heat exchangers, on which dust settles over time. In rooms with large (showcase) glazing, it is more efficient to use convectors, including convectors built into the floor structure. Such convectors can be structurally supplemented with a special fan to create a more powerful flow of heated air along the glazing. To date, there are steel and bimetallic convectors of various standard sizes. They also differ in appearance. Radiators give off a significant part of the heat by thermal radiation (radiation), i.e. heat the surrounding objects, which in turn give off heat to the room. As a rule, radiators are easier to clean from dust, so their use is recommended for rooms with increased requirements for air purity (for example, in healthcare facilities). To date, the main radiators on the market are cast iron, aluminum, bimetallic, steel tubular, steel panel and design radiators.
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Temperature controllers It is convenient to regulate the flow of hot water passing through the heating device using an individual thermostat. In recent years, individual thermostats in heating systems have been widely used in Russia. Structurally, the thermostat consists of two parts: a thermostatic valve and a thermostatic head. Initially (as a rule, a thermostatic valve is installed on the supply pipeline to the device). A thermostatic head is installed on the valve, which includes a special gas-filled bellows. The steam in the bellows takes on a pressure proportional to the ambient temperature. When the air temperature rises, the steam pressure increases, the corrugations of the bellows expand and contribute to the closure of the passage section for the passage of hot water in the valve body. When the air temperature in the room drops below the set value, the gas pressure in the bellows decreases, its corrugations are compressed, which leads to the opening of the flow section in the valve. According to manufacturers, the use of thermostats in heating systems, thanks to automatic control, can reduce heat consumption by up to 20%. To prevent the operation of the temperature controller from being affected by the heat rising from the pipeline, it is recommended to mount the valve in such a way that the thermostatic head is in a horizontal plane. In addition, thermostats can be used with remote temperature sensor (for example, if a heater with a thermostat is located in a niche, covered with a screen or curtains). If the installation of thermostats was not provided for in the existing heating system, then before installing them, it is necessary to consult with specialists. This armature has a hydraulic resistance of 1m water column on average. (0.1 atm.), Therefore, it should be clarified whether the available pressure in the system is enough for normal heating operation. We can say that the variety of heating devices, on the one hand, facilitates their choice, but on the other hand, gives rise to many comparisons and, as a result, doubts about the correctness of the choice made. Therefore, it is best to turn to specialists who will design a heating system, answer your questions, select heating devices in accordance with technical data and your wishes in terms of their appearance. |
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Source: TopClimat.ru
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