Description:

The buildings considered in the book can be classified as high-rise buildings. We hope that in the future there will be a book about domestic experience in designing engineering equipment for ultra-tall buildings, figuratively called skyscrapers.

Heat supply and heating of high-rise residential buildings

To the publication of the book

V. I. Livchak, Vice-President of NP AVOK, Head of Energy Efficiency in Construction at Mosgosexpertiza

In Moscow, half a century after the construction of seven "Stalinist" skyscrapers, the construction of high-rise buildings resumed. Now buildings above 40 floors have been built: in 2003 - "Edelweiss" on Davydkovskaya St., vl. 3 (height 176 m, 43 floors), "Scarlet Sails" building 4 (179 m, 48 floors) on Aviation Street, vl. 77–79; in 2004 - "Vorobyovy Gory" (188 m, 49 floors) on Mosfilmovskaya st., vl. 4-6, "Triumph Palace" - the highest residential building in Europe (225 m, 59 floors, with a spire - 264 m), Chapaevsky lane, vl. 2.

Several dozens of buildings with a height of 30-50 floors are planned for construction under the city's investment program "The New Ring of Moscow". A number of skyscrapers over 300 meters high are being built in the Moscow City business center, and the apotheosis of everything is the construction of the Rossiya Tower, 600 meters high, designed by the English architect Norman Foster, the design of which began in 2006.

The project of the residential building "Edelweiss" was carried out by TsNIIEPzhilischa, the engineering part of the other listed high-rise residential buildings built by the company "DON-stroy" was the fruit of the creativity of the design and production company "Alexander Kolubkov" under the leadership of A. N. Kolubkov and bearing his name. It is also interesting that DON-Stroy itself operates the houses it builds, and therefore the applied solutions are confirmed by the practice of their work.

The experience gained in the design of these buildings and their operation was the basis of the book " Engineering equipment high-rise buildings”, published by AVOK-PRESS in 2007 under the general editorship of prof. Moscow Architectural Institute M. M. Brodach.

In our opinion, all buildings by height can be divided into 5 categories:

Up to five floors where installation of elevators is not required - low-rise buildings;

Up to 75 m (25 floors), within which vertical zoning for fire compartments is not required - multi-storey buildings;

76–150 m - high-rise buildings;

151–300 m - high-rise buildings;

Over 300 m - ultra-tall buildings.

The gradation is a multiple of 150 m due to a change in the calculated outdoor temperature for the design of heating and ventilation - every 150 m it decreases by 1 ° C.

The design features of buildings above 75 m are due to the fact that they must be vertically divided into sealed fire compartments (zones), the boundaries of which are enclosing structures that provide the required fire resistance limits for localizing a possible fire and preventing it from spreading to adjacent compartments. The height of the zones should be 50–75 m, and it is not necessary to separate vertical fire compartments with technical floors, as is customary in warm countries, where technical floors do not have walls and are used to collect people in case of fire and their subsequent evacuation. In countries with a harsh climate, the need for technical floors is due to the requirements for the placement of engineering equipment. When it is installed in the basement, only part of the floor located at the border of fire compartments can be used to place smoke protection fans, the rest - for working rooms. With a cascade connection scheme for heat exchangers, as a rule, they, together with pumping groups, are placed on technical floors, where they need more space, and occupy the entire floor, and sometimes two floors in ultra-tall buildings.

The buildings considered in the book can be classified as high-rise buildings. We hope that in the future there will be a book about domestic experience in designing engineering equipment for ultra-tall buildings, figuratively called skyscrapers.

Below, an analysis of design solutions for heat and water supply and heating of the listed residential buildings will be given. And this is only a part of the subject to which this book is devoted, beyond the scope of this article is the analysis of advanced solutions implemented in a number of foreign high-rise buildings, and the features of the influence of the outdoor climate, experience in designing ventilation and air conditioning systems for residential and public buildings, fire safety systems, water disposal and waste disposal, automation and dispatching, also given in the book "Engineering Equipment for High-Rise Buildings".

Heat supply

A feature of the design of heat and water supply systems is that all pumping and heat exchange equipment of the considered high-rise residential buildings is located at ground level or minus the first floor. This is due to the danger of placing pipelines superheated water on residential floors, the lack of confidence in the adequacy of protection against noise and vibration of adjacent residential premises during the operation of pumping equipment and the desire to save scarce space to accommodate more apartments.

Such a solution is possible due to the use of high-pressure pipelines, heat exchangers, pumps, shut-off and control equipment that can withstand operating pressures up to 25 atm. Therefore, in the piping of heat exchangers from the side of local water, butterfly valves with collar flanges, pumps with a U-shaped element, pressure regulators “to themselves” of direct action installed on the make-up pipeline, electromagnetic valves rated for a pressure of 25 atm are used. at the filling station for heating systems.

With a building height above 220 m, due to the occurrence of ultra-high hydrostatic pressure, it is recommended to use a cascade scheme for connecting zone heat exchangers and hot water supply, an example of such a solution is given in the book.

Another feature of the heat supply of completed high-rise residential buildings is that in all cases the source of heat supply is urban heating network. Connection to them is made through the central heating station, which occupies a rather large area, for example, in the Vorobyovy Gory complex, it occupies 1,200 m 2 with a room height of 6 m (rated power 34 MW).

CHP includes heat exchangers with circulation pumps for heating systems of different zones, heat supply systems for ventilation and air conditioning heaters, hot water supply systems, pumping stations filling heating systems and pressure maintenance systems with expansion tanks and automatic control equipment, emergency electric hot water storage water heaters. Equipment and pipelines are arranged vertically so that they are easily accessible during operation. A central passage with a width of at least 1.7 m passes through all the central heating stations for the possibility of moving special loaders, which make it possible to remove heavy equipment when it is replaced (Fig. 1).

Picture 1.

This decision is also due to the fact that high-rise complexes, as a rule, are multifunctional in purpose with a developed stylobate and underground part, on which several buildings can be located. Therefore, in the Vorobyovy Gory complex, which includes 3 high-rise residential buildings of 43-48 floors and 4 buildings of 17-25 floors, united by a five-level stylobate part, technical collectors with numerous pipelines depart from this single central heating station, and to reduce them in the technical In the zone of high-rise buildings, booster pumping stations for water supply were located, which pump cold and hot water into each zone of high-rise buildings.

Another solution is also possible - the central heating station is used to introduce urban heating networks to the facility, to place a pressure drop regulator “after itself”, a heat energy metering unit and, if necessary, a cogeneration unit and can be combined with one of the individual local heating points (ITP), employees to join local systems heat consumption, close in location to this heat point. From this CHP, superheated water is supplied through two pipes, and not through several from the comb, as in the previous case, to local ITPs located in other parts of the complex, including on the upper floors, according to the principle of proximity to the heat load. With this solution, there is no need to connect the internal heating system for heaters supply systems in an independent circuit through a heat exchanger. The heater itself is a heat exchanger and is connected directly to the superheated water pipelines with pumping to improve the quality of load control and increase the reliability of the protection of heaters from freezing.

One of the solutions for redundant centralized heat and power supply of high-rise buildings can be the installation of autonomous mini-CHPs based on gas turbine (GTP) or gas piston (GPU) plants that simultaneously produce both types of energy. Modern means of protection against noise and vibration make it possible to place them directly in the building, including on the upper floors. As a rule, the power of these units does not exceed 30-40% of the maximum required power of the facility, and in the normal mode these units operate, supplementing the centralized power supply systems. With a higher capacity of cogeneration plants, problems arise in transferring excesses of one or another energy carrier to the network.

The book provides an algorithm for calculating and selecting a mini-CHP when the object is supplied with offline power and an analysis of optimizing the choice of a mini-CHP using the example of a specific project. With a shortage of only thermal energy for the object under consideration, an autonomous heat supply source (AHS) in the form of a boiler room with hot water boilers can be taken as a source of heat supply. Attached, located on the roof or protruding parts of the building, or stand-alone boiler rooms designed in accordance with SP 41-104-2000 can be used. The possibility and location of AIT should be linked to the whole complex of its impact on environment, including a residential high-rise building.

Heating

Water heating systems of high-rise buildings are zoned in height and, as already mentioned, if fire compartments are separated by technical floors, then the zoning of heating systems, as a rule, coincides with fire compartments, since technical floors are convenient for laying distribution pipelines. In the absence of technical floors, the zoning of heating systems may not coincide with the division of the building into fire compartments. Fire authorities allow crossing the boundaries of fire compartments with pipelines of water-filled systems, and the height of the zone is determined by the value of the allowable hydrostatic pressure for the lower heaters and their piping.

Initially, the design of zonal heating systems was carried out as for ordinary multi-storey buildings. As a rule, two-pipe heating systems with vertical risers and lower wiring of the supply and return lines passing through the technical floor were used, which made it possible to turn on the heating system without waiting for the construction of all floors of the zone. Such heating systems were implemented in the residential complexes "Scarlet Sails", "Vorobyovy Gory", "Triumph Palace". Each riser is equipped with automatic balancing valves to ensure automatic distribution of the coolant among the risers, and each heater is equipped with an automatic thermostat with increased hydraulic resistance to provide the tenant with the opportunity to set the desired air temperature in the room and minimize the influence of the gravitational component of the circulation pressure and turn on / off thermostats on other heaters connected to this riser.

Further, in order to avoid unbalancing the heating system associated with the unauthorized removal of thermostats in individual apartments, which has repeatedly occurred in practice, it was proposed to switch to a heating system with an upper distribution of the supply line with an associated movement of the coolant along the risers. This equalizes the pressure losses of the circulation rings through the heating devices, regardless of which floor they are located on, increases the hydraulic stability of the system, guarantees the removal of air from the system and facilitates the setting of thermostats.

However, subsequently, as a result of an analysis of various solutions, the designers came to the conclusion that the best heating system, especially for buildings without technical floors, are systems with flat-by-apartment horizontal wiring connected to vertical risers, which, as a rule, pass along stairwell, and made according to a two-pipe scheme with a lower wiring of the mains. Such a system was designed in the crowning part (9 floors of the third zone) of the Triumph Palace high-rise complex and in a 50-storey building under construction without intermediate technical floors on the street. Pyreva, 2.

Apartment heating systems are equipped with a unit with shut-off, balancing valves and drain fittings, filters and a heat energy meter. This node should be located outside the apartment in the stairwell for unhindered access to the maintenance service. In apartments over 100 m 2, the connection is made not by a loop laid along the perimeter of the apartment (since the diameter of the pipeline increases with increasing load, and as a result, installation becomes more complicated and the cost increases due to the use of expensive large fittings), but through an intermediate apartment distribution cabinet, in which the comb is installed, and from it the coolant is directed by pipelines of smaller diameter to the heating appliances in a two-pipe pattern.

Pipelines are used from heat-resistant polymeric materials, as a rule, from cross-linked PEX polyethylene (the justification for its use is given in the book), the laying is carried out in the preparation of the floor. The design parameters of the coolant, based on the technical specifications for such pipelines, are 90–70 (65) ° С for fear that a further decrease in temperature leads to a significant increase in the heating surface of heating devices, which is not welcomed by investors due to the increase in the cost of the system. The experience of using metal-plastic pipes in the heating system of the Triumph Palace complex was considered unsuccessful. During operation, as a result of aging, the adhesive layer is destroyed and the inner layer of the pipe “collapses”, as a result of which the flow area narrows and the heating system stops working normally.

The authors of the book believe that for apartment-by-apartment wiring, the best solution is to use automatic balancing valves ASV-P (PV) on the return pipeline and shut-off and measuring valves ASV-M (ASV-1) on the supply pipeline. The use of this pair of valves makes it possible not only to compensate for the influence of the gravitational component, but also to limit the flow to each apartment in accordance with the parameters. Valves are usually selected according to the diameter of the pipelines and adjusted to maintain a pressure drop of 10 kPa. This valve setting value is selected based on the value of the required pressure loss on radiator thermostats to ensure their optimal performance. The flow limit per apartment is set by the setting on the ASV-1 valves, taking into account that in this case the pressure losses on these valves must be included in the differential pressure maintained by the ASV-PV regulator.

The use of apartment horizontal heating systems compared to a system with vertical risers leads to a reduction in the length of the main pipelines (they only fit the stair riser, and not to the most remote riser in the corner room), reduce heat losses from pipelines, simplify the floor-by-floor commissioning of the building and increase hydraulic stability of the system. The cost of installing an apartment system is not much different from standard ones with vertical risers, however, the service life is higher due to the use of pipes made of heat-resistant polymer materials.

In apartment heating systems, it is much easier and with absolute visibility for residents to carry out heat energy metering. We must agree with the opinion of the authors that although the installation of heat meters does not apply to energy-saving measures, however, payment for actually consumed thermal energy is a powerful incentive for residents to take care of its spending. Naturally, this is achieved, first of all, by the obligatory use of thermostats on heating appliances. The experience of their operation has shown that in order to avoid affecting the thermal regime of adjacent apartments, the thermostat control algorithm should be limited to lowering the temperature in the room they serve at least 15-16 ° C, and heating appliances should be selected with a power margin of at least 15%.

Water supply

To improve the reliability of water supply in buildings up to 250 m, at least two inputs from independent water supplies (separate lines of the external ring water supply network) are provided, with a higher height, each input is laid in two lines, each of which must be designed for a pass of at least 50% of the calculated expense.

In order to increase reliability and ensure uninterrupted operation of hot water supply in all high-rise residential buildings, in addition to high-speed hot water heaters, the installation of capacitive electric water heaters is provided, which are turned on during a shutdown of the heating network for scheduled maintenance or accidents. The volume of these backup water heaters is selected based on the one and a half hour peak consumption of hot water. The power of the heating element is assigned in such a way that the heating time for a given volume of water is 8 hours - this is the interval between the peak morning and evening water intakes.

As a rule, there are a lot of backup electric water heaters (there are objects where their number reaches 13 units), and for the stability of their operation, the water heaters should be turned on according to the scheme with associated water movement. If the water heater is the first to connect hot water, it should be the last one to supply heated water. The operating pressure of electric water heaters does not exceed 7 atm. This determines the height of the zone of water supply systems. Therefore, it is not necessary that the number of zones in water supply systems coincide with heating. So, in a 50-storey residential building on the street. Pyriev, there are 3 vertical zones for the heating system and 4 for hot and cold water supply (Fig. 2). For the latter systems, the number of zones is the same to enable redundancy between them.

Figure 2 () Zoning of engineering systems

Another feature of the hot water supply system of the listed high-rise buildings is that, regardless of the number of zones, a single heat exchanger is installed for the entire system, and then hot water is pumped into the corresponding zone by separate booster pumping stations. Also, for cold water, there are their own booster pumping stations for each zone, which increases the reliability of the water supply system, allowing in emergency situations to supply water through hot water pipelines.

The circulation pipelines of different zones are connected to a common comb through a node that includes, in addition to stop valves and check valve, downstream pressure regulator and flow regulator. This scheme was adopted after a lot of trial and error. Electric control valves were installed first. During operation, it turned out that their response speed is not enough for normal operation. It was necessary to find equipment capable of responding more quickly to changes in pressure in the circulation pipeline. As a result, direct acting pressure regulators were chosen. Initially, they were delivered without flow regulators, but since the circulation pumps contribute to airing, these pressure regulators began to work like chokes with unacceptable noise. To eliminate this defect, they tried to adjust the system more carefully, but then they installed flow regulators, after which the described effect disappeared.

So that a change in pressure in the city water supply does not affect the stability of maintaining pressure by pumping stations, a pressure regulator "after itself" is installed at the inlet of the water supply. If before the installation of this regulator, the pressure spread was 0.6–0.9 atm., Then after installation it stabilized at the level of 0.2–0.4 atm. At the hot water supply inlet (after the heat exchangers, in front of the pumping station of each zone), their own pressure regulators “after themselves” are also installed, thanks to which false operation of check valves and the inclusion of standby pumps without special need are excluded.

The water supply system, as a rule, is organized with horizontal apartment wiring. Such a solution has been successfully implemented in the high-rise residential complexes "Vorobyovy Gory", "Triumph Palace" and on the street. Pyriev. In this case, the risers of the water supply system are laid in the stair-lift hall, from where hot and cold water pipelines are supplied to the apartment. The system is equipped with cold and hot water meters, which, together with filters and pressure regulators, are installed in distribution cabinets in the stair-lift hall. In order to avoid the overflow of water (from a cold main to a hot one and vice versa) resulting from improper operation of plumbing equipment, check valves are installed at the inlets to apartments on the supply pipelines of cold and hot water.

Piping from risers to apartments and in apartments is made of cross-linked polyethylene pipes (PEX-pipes). In apartments, it is advisable to use collector wiring, when water is supplied to each water tap from the collector through a separate pipe, this minimizes the influence of neighboring devices on each other (when one mixer is turned on, the spout temperature on the other changes). Risers are laid from steel pipes, and just like in the heating system, hot water risers are equipped with compensators and fixed supports. Estimated circulation in the amount of 40% of the calculated water intake is set using control and balancing valves.

With horizontal wiring of the hot water supply system, you can refuse to install heated towel rails. Operating experience has shown that even in buildings equipped with heated towel rails, up to 70% of apartment owners do not use them. They either leave the bathroom without towel warmers at all, or use electric heated towel rails. The use of electric heated towel rails, from the point of view of the owner of the apartment, is more convenient, since it turns on only as needed.

These are the solutions for the systems of heat supply and heating of the tallest residential buildings built to date in Moscow. They are clear, logical and do not fundamentally differ from the solutions used in the design of conventional multi-storey buildings with a height of less than 75 m, with the exception of the division of heating and water supply systems into zones. But within each zone, standard approaches to the implementation of these systems remain. Greater attention is paid to the installations for filling heating systems and maintaining pressure in them and on each floor of water supply systems, as well as in circulation lines from different zones before connecting them to a common comb, automatic control of heat supply and distribution of the coolant to implement comfortable and economical modes, redundancy operation of equipment to ensure uninterrupted supply of consumers with heat and water.

Distinctive feature is an application for the purpose of uninterrupted supply hot water emergency capacitive electric water heaters for an hour and a half supply of water. But it seems that their potential is not being fully utilized. In addition to turning them on in case of an accident or scheduled preventive maintenance of heating networks, they could be tied in such a way that their capacity is used to relieve peak heat loads on the heat supply system.

This ingenious scheme, proposed by A. V. Khludov, the progenitor of hot water supply technology, includes a water heater, a storage tank and a pump that performs the function of charging the tank with hot water (Fig. 3). When the accumulator is charged, cold water flows in parallel flows into the water heater and into the accumulator tank, displacing hot water from the accumulator upwards into the consumer system. Thus, with a large drawdown, the consumer receives hot water from the water heater and accumulator into his system. With a decrease in water intake, the pump squeezes out the excess of water heated in the water heater into the storage tank, thereby displacing cold water from the bottom of the battery into the water heater, i.e., the battery is charging. This allows you to equalize the load on the water heater and reduce its heating surface.

The disadvantages of the adopted solutions include ignoring the use of energy-saving solutions, such as partial replacement of energy demand through the use of autonomous energy-producing gas turbine or gas piston units, solar photovoltaic or water heating elements, heat pumps using low-potential ground energy, ventilation emissions. It should also be noted the insufficient use of centralized cooling to improve the comfort of living in apartments and eliminate negative impact on the architecture of the building haphazardly hung on the facade of the external blocks of split systems. High-rise buildings, being advanced in terms of architectural and structural solutions, should be an example for the implementation of promising technologies in engineering systems.

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An apartment in a high-rise building is an urban alternative to private houses, and very a large number of of people. The popularity of city apartments is not strange, because they have everything that a person needs for comfortable living: heating, sewerage and hot water supply. And if the last two points do not need special introduction, then the heating scheme of a multi-storey building requires detailed consideration. From the point of view of design features, the centralized one has a number of differences from autonomous structures, which allows it to provide the house with thermal energy in the cold season.

Features of the heating system of apartment buildings

When installing heating in multi-storey buildings, it is imperative to comply with the requirements established by regulatory documentation, which includes SNiP and GOST. These documents state that heating structure should provide apartments with a constant temperature within 20-22 degrees, and humidity should vary from 30 to 45 percent.

Despite the existence of standards, many houses, especially old ones, do not meet these indicators. If this is the case, then first of all you need to do the installation of thermal insulation and change the heating devices, and only then contact the heat supply company. The heating of a three-story house, the scheme of which is shown in the photo, can be cited as an example of a good heating scheme.

To achieve the required parameters, a complex design is used that requires high-quality equipment. When creating a project heating system apartment building specialists use all their knowledge to achieve an even distribution of heat in all sections of the heating main and create a comparable pressure on each tier of the building. One of the integral elements of the work of such a design is the work on a superheated coolant, which provides for the heating scheme of a three-story house or other skyscrapers.

How it works? Water comes directly from the thermal power plant and is heated to 130-150 degrees. In addition, the pressure is increased to 6-10 atmospheres, so the formation of steam is impossible - high pressure will drive water through all floors of the house without loss. The temperature of the liquid in the return pipeline in this case can reach 60-70 degrees. Of course, at different times of the year temperature regime may vary, since it is directly related to the ambient temperature.

Purpose and principle of operation of the elevator unit

It was said above that the water in the heating system high-rise building heats up to 130 degrees. But consumers do not need such a temperature, and it is absolutely pointless to heat the batteries to such a value, regardless of the number of floors: the heating system of a nine-story building in this case will not differ from any other. Everything is explained quite simply: the heating supply in multi-storey buildings is completed by a device that goes into the return circuit, which is called an elevator unit. What is the meaning of this node, and what functions are assigned to it?

The coolant heated to a high temperature enters, which, according to the principle of its operation, is similar to a dosing injector. It is after this process that the liquid carries out heat exchange. Leaving through the elevator nozzle, the coolant under high pressure out through the return line.

In addition, through the same channel, the liquid enters the heating system for recirculation. All these processes together make it possible to mix the coolant, bringing it to optimum temperature, which is enough to heat all apartments. The use of an elevator node in the scheme allows you to provide the highest quality heating in high-rise buildings, regardless of the number of storeys.

Design features of the heating circuit

There are different valves in the heating circuit behind the elevator unit. Their role cannot be underestimated, since they make it possible to regulate heating in individual entrances or in the whole house. Most often, the adjustment of the valves is carried out manually by employees of the heat supply company, if such a need arises.

AT modern buildings often used additional elements, such as collectors, thermal and other equipment. AT last years almost every heating system in high-rise buildings is equipped with automation to minimize human intervention in the operation of the structure (read: ""). All the described details allow to achieve better performance, increase efficiency and make it possible to distribute heat energy more evenly throughout all apartments.

Piping in a multi-storey building

As a rule, in multi-storey buildings, a single-pipe wiring diagram with top or bottom filling is used. The location of the forward and return pipes can vary depending on many factors, including even the region where the building is located. For example, the heating scheme in a five-story building will be structurally different from heating in three-story buildings.

When designing a heating system, all these factors are taken into account, and the most successful scheme is created that allows you to bring all the parameters to the maximum. The project may involve various options pouring the coolant: from the bottom up or vice versa. In individual houses, universal risers are installed, which ensure the rotation of the movement of the coolant.

Types of radiators for heating apartment buildings

In multi-storey buildings, there is no single rule that allows the use of a specific type of radiator, so the choice is not particularly limited. The heating scheme of a multi-storey building is quite versatile and has a good balance between temperature and pressure.

The main models of radiators used in apartments include the following devices:

1. Cast iron batteries. Often used even in the most modern buildings. They are cheap and very easy to install: as a rule, apartment owners install this type of radiator on their own.
2. Steel heaters. This option is a logical continuation of the development of new heating devices. Being more modern, steel heating panels demonstrate good aesthetic qualities, are quite reliable and practical. Very well combined with the regulating elements of the heating system. Experts agree that it is steel batteries that can be called optimal when used in apartments.
3. Aluminum and bimetallic batteries. Products made of aluminum are very much appreciated by the owners of private houses and apartments. aluminum batteries have the best performance when compared with previous options: excellent external data, low weight and compactness are perfectly combined with high performance. The only disadvantage of these devices, which often scares off buyers, is the high cost. Nevertheless, experts do not recommend saving on heating and believe that such an investment will pay off pretty quickly.

Conclusion

Fulfill repair work in the heating system of an apartment building on its own is also not recommended, especially if it is heating in the walls panel house: practice shows that residents of houses, not having the appropriate knowledge, are able to throw away an important element of the system, considering it unnecessary.

Centralized heating systems demonstrate good qualities, but they need to be constantly maintained in working order, and for this you need to monitor many indicators, including thermal insulation, equipment wear and regular replacement of spent elements.

When designing professional heating systems, it is necessary to take into account all factors - both external and internal. This is especially true for heating schemes for multi-apartment buildings. What is special about the heating system of a multi-storey building: pressure, circuits, pipes. First you need to understand the specifics of its arrangement.

Features of heat supply of multi-storey buildings

Autonomous heating of a multi-storey building should perform one function - the timely delivery of the coolant to each consumer while maintaining its technical qualities(temperature and pressure). To do this, the building must be provided with a single distribution unit with the possibility of regulation. In autonomous systems, it is combined with water heating devices - boilers.

The characteristic features of the heating system of a multi-storey building are in its organization. It should consist of the following mandatory components:

• distribution node. With its help, hot water is supplied through the mains;
• Pipelines. They are designed to transport the coolant to individual rooms and premises of the house. Depending on the method of organization, there is a single-pipe or two-pipe heating system for a multi-storey building;
• Control and regulation equipment. Its function is to change the characteristics of the coolant depending on external and internal factors, as well as its qualitative and quantitative accounting.

In practice, the heating scheme of a residential multi-storey building consists of several documents, which include, in addition to the drawings, the calculation part. It is compiled by special design bureaus and must comply with current regulatory requirements.

The heating system is an integral part of a multi-storey building. Its quality is checked upon delivery of the facility or during scheduled inspections. This is the responsibility of the management company.

Pipe routing in a multi-storey building

For the normal operation of the heat supply of the building, it is necessary to know its basic parameters. What pressure in the heating system of a multi-storey building, as well as the temperature regime will be optimal? According to the regulations, these characteristics should have the following values:

• Pressure. For buildings up to 5 floors - 2-4 atm. If the number of floors is nine - 5-7 atm. The difference lies in the pressure of hot water to transport it to the upper levels of the house;
• Temperature. It can vary from +18°С to +22°С. This only applies to residential properties. On landings and non-residential rooms, a decrease to + 15 ° С is allowed.

Having determined the optimal values ​​of the parameters, you can proceed to the choice of heating wiring in a multi-storey building.

It largely depends on the number of storeys of the building, its area and the power of the entire system. The degree of thermal insulation of the house is also taken into account.

The pressure difference in the pipes on the 1st and 9th floors can be up to 10% of the standard. This is a normal situation for a multi-storey building.

Single-pipe heating distribution

This is one of the economical options for organizing heat supply in a building with a relatively large area. For the first time, a mass-produced one-pipe heating system for a multi-storey building began to be used for "Khrushchev". The principle of its operation is the presence of several distribution risers, to which consumers are connected.

The coolant is supplied through one pipe loop. The absence of a return line greatly simplifies the installation of the system, while reducing the cost. However, at the same time, the Leningrad heating system of a multi-storey building has a number of disadvantages:

• Uneven heating of the room, depending on the remoteness of the hot water intake point (boiler or collector unit). Those. options are possible when the consumer connected earlier according to the scheme will have hotter batteries than those following in the chain;
• Problems with adjusting the degree of heating of radiators. To do this, you need to make a bypass on each radiator;
• Difficult balancing of a single-pipe heating system of a multi-storey building. It is carried out with the help of thermostats and valves. In this case, a system failure is possible even with a slight change in the input parameters - temperature or pressure.

Currently, the installation of a single-pipe heating system for a multi-storey building of a new building is extremely rare. This is due to the difficulty of individual accounting of the coolant in a separate apartment. So, in residential buildings of the Khrushchev project, the number of distribution risers in one apartment can reach up to 5. Those. for each of them it is necessary to install an energy consumption meter.

A correctly drawn up estimate for heating a multi-storey building with a one-pipe system should include not only the cost of Maintenance, but also the modernization of pipelines - the replacement of individual components with more efficient ones.

Two-pipe heating distribution

To increase work efficiency, it is best to install a two-pipe heating system in a multi-storey building. It also consists of distribution risers, but after the coolant passes through the radiator, it enters the return pipe.

Its main difference is the presence of a second circuit that performs the function of a return line. It is necessary to collect the cooled water and transport it to the boiler or to the thermal station for further heating. During the design and operation, it is necessary to take into account a number of features of the heating system of a multi-storey building of this type:

• The ability to adjust the temperature level in individual apartments and in the entire highway as a whole. To do this, you need to install mixing units;
• To perform repairs or maintenance work, you do not need to turn off the entire system, as in the Leningrad heating scheme for a multi-storey building. It is enough to block the flow to a separate heating circuit with the help of shut-off valves;
• Low inertia. Even with good balancing of the single-pipe heating system of a multi-storey building, the consumer needs to wait 20-30 seconds until hot water reaches the radiators through pipelines.

What is the optimal pressure in the heating system of a multi-storey building? It all depends on how tall it is. It should ensure that the coolant is raised to the desired height. In some cases, it is more efficient to install intermediate pumping stations in order to reduce the load on the entire system. Wherein optimal value pressure should be from 3 to 5 atm.

Before purchasing radiators, you need to find out from the heating scheme of a residential multi-storey building its characteristics - pressure and temperature conditions. Batteries are selected based on this data.

Heat supply of a multi-storey building

The distribution of heating in a multi-storey building is important for the operational parameters of the system. However, in addition to this, the characteristics of heat supply should be taken into account. An important of them is the method of supplying hot water - centralized or autonomous.

In overwhelming cases, they make a connection to the central heating system. This allows you to reduce the current costs in the estimate for heating a multi-storey building. But in practice, the level of quality of such services remains extremely low. Therefore, if there is a choice, preference is given to autonomous heating multi-storey building.

Autonomous heating of a multi-storey building

In modern multi-storey residential buildings, it is possible to organize an independent heat supply system. It can be of two types - apartment or common house. In the first case, an autonomous heating system of a multi-storey building is carried out in each apartment separately. To do this, they make an independent wiring of pipelines and install a boiler (most often a gas one). General house implies the installation of a boiler room, to which special requirements are imposed.

The principle of its organization is no different from a similar scheme for a private country house. However, there are a number important points that need to be taken into account:

• Installation of several heating boilers. One or more of them must necessarily perform a duplicate function. In case of failure of one boiler, another must replace it;
• Installation of a two-pipe heating system of a multi-storey building, as the most efficient;
• Drawing up a schedule for scheduled maintenance and preventive maintenance. This is especially true for heating heating equipment and security groups.

Taking into account the peculiarities of the heating scheme of a particular multi-storey building, it is necessary to organize an apartment heat metering system. To do this, for each incoming pipe from central riser energy meters need to be installed. That is why the Leningrad heating system of a multi-storey building is not suitable for reducing current costs.

Centralized heating of a multi-storey building

How can the heating layout in an apartment building change when it is connected to the central heating supply? The main element of this system is the elevator unit, which performs the functions of normalizing the coolant parameters to acceptable values.

The total length of the central heating mains is quite large. Therefore, in the heating point, such parameters of the coolant are created so that heat losses are minimal. To do this, increase the pressure to 20 atm., Which leads to an increase in the temperature of hot water up to +120°C. However, given the characteristics of the heating system in an apartment building, the supply of hot water with such characteristics to consumers is not allowed. To normalize the parameters of the coolant, an elevator assembly is installed.

It can be calculated for both two-pipe and single-pipe heating systems of a multi-storey building. Its main functions are:

• Reducing pressure with an elevator. A special cone valve regulates the amount of coolant inflow into the distribution system;
• Lowering the temperature level to + 90-85 ° С. For this purpose, a mixing unit for hot and cooled water is designed;
• Coolant filtration and oxygen reduction.

In addition, the elevator unit performs the main balancing of the single-pipe heating system in the house. To do this, it provides shut-off and control valves, which in automatic or semi-automatic mode regulates pressure and temperature.

The disadvantage of a dependent connection system with water displacement is the possibility of increasing the hydrostatic pressure in it, which is directly transmitted through the return heat pipe to the return line of the system to a value that is dangerous for the integrity of the heating devices (exceeding their operating pressure).

A mixing pump can be used in a heating system with significant hydraulic resistance, while when using an elevator mixing plant, the hydraulic resistance of the system should be relatively small. Nevertheless, water jet elevators are widely used due to their trouble-free and silent operation.

Return water from the heating system is mixed with high-temperature water from the external heat supply using a mixing pump or water jet elevator. When using a mixing pump, not only local qualitative and quantitative regulation of water parameters is possible, but also the preservation of water circulation in the heating system in case of an emergency stop of its supply from external heat pipelines.

The heat carrier in the pumped water heating system can be heated in a local hot water boiler house (local heating supply) or high-temperature water supplied from a CHP plant or a central heating plant (district heating supply). Depending on the source of heat supply, the parameters of heat carriers in the heating network and in the heating system, the equipment of the heat point changes.

CONNECTION OF HEATING SYSTEMS TO EXTERNAL HEAT NETWORKS

LECTURE 12

An indirect regulator typically uses electrical energy to heat a reduced volume bulb, which in turn is connected to a control valve stem. For individual manual control of the heat transfer of devices, taps and valves and air valves in the casing of the convectors.

For individual automatic control, a temperature controller of direct and indirect action is used. The principle of operation of a direct-acting regulator is based on a change in the volume of a medium with pressure or a decrease in its temperature. A change in the volume of the medium of the thermoactive material (for example, rubber) directly causes the movement of the regulator valve in the flow of the main coolant.

Operational regulation of heat transfer devices can be automated. Local automatic control in the heating point is carried out, focusing on changes in the outside air temperature. Individual automatic regulation of heat transfer of the device occurs when the air temperature in the room deviates.

A schematic diagram of a pumped water heating system with local heat supply from a hot water boiler house located in or near a heated building is shown in fig. 12.I, a.

Rice. 12.1 Schematic diagrams pumped water heating systems for local heat supply (a) and centralized (b, c, d)

1 circulation pump; 2- boiler; 3-fuel supply; four- expansion tank. 5 - heating devices; 6 plumbing; 7 - heat exchanger? 8- make-up pump: 9, 1O-external return and supply heat pipes 11 - mixing plant

Water is heated in the boiler room to a temperature of TI(tg). Hot water distributed to heating devices. Water movement is created circulation pump, included in the common return line, where the water of the devices cooled to a temperature of T2 (to) is collected. An expansion tank is connected to the return line. Initial filling and replenishment of the system in case of leakage (make-up is carried out cold water from the plumbing check valve, which excludes the leakage of water from the system when the pressure in the water supply system decreases.

With district heating, three main schemes are used for connecting a pumped water heating system to external heat pipelines (Fig. 12.1, b-d).

An independent scheme for connecting a pumped water heating system to external heat pipelines (Fig. 12.1, b) is close in its elements to the scheme for local heat supply. Filling and make-up of the system is carried out with deaerated water from an external heating network. In this case, the pressure in it is used or a make-up pump is used if this pressure is not enough. In a water-to-water heat exchanger, primary high-temperature water (temperature TII(t1) from the external supply heat pipe heats up the secondary - local water and, cooling down to T2 (t2), is removed to the external return heat pipe.

An independent circuit is used to obtain a separate thermal-hydraulic mode in a heating system, into which, for some reason, direct supply of high-temperature water is unacceptable. The advantage of an independent scheme, in addition to providing a thermal-hydraulic regime, individual for each building, is the possibility of maintaining circulation using the heat content of water for some time, usually sufficient to eliminate emergency damage to external heat pipelines. A heating system with an independent scheme lasts longer than a system with a local boiler, due to the reduction in the corrosiveness of water.

A dependent scheme with water mixing for connecting the heating system to external heat pipes (Fig. 12.1) c) is simpler in design and maintenance. Its cost is lower than the cost of an independent circuit due to the exclusion of such elements as a heat exchanger, expansion tank and make-up pump, whose functions are performed centrally at the thermal plant. This connection scheme is selected when the system requires water temperature TI and it is allowed to increase the hydrostatic pressure to the value under which there is water in the external return heat pipe.

The dependent once-through scheme for connecting a water heating system to external heat pipelines is the simplest in design and maintenance: the system does not have such elements as a heat exchanger or mixing plant, circulation and make-up pumps, and an expansion tank (Fig. 12.1, d). Direct-flow connection is used when high-temperature water supply (TI=TII) and significant hydrostatic pressure are allowed in the system, or when water is supplied at temperatures below 100°C. The heating system is characterized by reduced cost and reduced metal consumption.

The disadvantages of a direct-flow connection are the impossibility of local quality regulation and the dependence of the thermal regime of the heating system (and rooms) on the impersonal water temperature in the external supply heat pipeline. The height of buildings in which high temperature water can be used is limited due to the need to keep the hydrostatic pressure in the system high enough to prevent water from boiling.

With district heating using independent and dependent connection in the heating system, deaerated water is circulated (the air is removed at the thermal station). This not only simplifies the collection and removal of air from the system (tactically, air is removed only during the start-up period after installation and repair), but also increases its service life.

High-rise buildings are usually zoned - divided into parts - zones of a certain height, between which technical floors are placed. In water heating systems, the height of the zone is determined by the allowable water pressure (working pressure) in the lowest-lying devices and the possibility of placing equipment and communications on technical floors.

2017-03-15

Recently, projects for heating public buildings have begun to provide for horizontal water heating systems with floor-by-floor wiring above the plinth or in the floor structure, with parallel (two-pipe) or sequential (single-pipe) water supply to the device. Moreover, in large areas with several windows on the same facade, radiators are installed as heating devices, connected to the main line according to the “top-down” and “bottom-up” scheme. On fig. 1, 2 and 3 show possible schemes of horizontal heating systems using HERZ shut-off and control and thermostatic fittings.

Such systems have a number of serious drawbacks. Firstly, the number of radiators corresponds to the number of windows, which leads to a rise in the cost of the heating system, since each radiator must be equipped with an air vent (for example, a Mayevsky tap) to remove air and expensive shut-off and thermostatic valves.

Secondly, when the water velocity in the radiator collector is less than 0.20-0.25 m/s, air accumulation in the radiator is inevitable, especially at the beginning of the heating season, which makes it necessary to systematically remove air from the radiator. The water velocity may be higher than the indicated one if the heat load of the radiator is not less than 9 kW.

Thirdly, the length of the radiator in some cases is less than 50-75% of the width of the window opening, which does not meet the requirements of SP 60.13330.2013. Fourthly, the installation of a system with plinth laying of highways, and even more so with laying them in the floor in thermal insulation, is more difficult.

In addition, with a sequential, single-pipe water supply to the radiator, the number of sections of a collapsible radiator or the type of a non-collapsible radiator under the windows must be different. This, in fact, further complicates the selection of a heating device.

The advantage of horizontal water heating systems with laying lines in thermal insulation in the floor structure can only be attributed to the reduction of associated heat losses in the line, which allows water to be supplied to devices with approximately the same temperature. The heat output of one linear meter of an insulated pipe, for example, ∅ 20 mm, with a difference between the average temperature of the water in the heater and the air temperature in the room equal to 60 ° C, is no more than 20 W, that is, almost four times less than the heat output of an uninsulated, openly laid pipe in a horizontal position.

In order to reduce the cost of heating systems in rooms with two or more windows on one facade, it is proposed to install convectors as heating devices, connected in series through water, as shown in Fig. four.

Firstly, in this case, it is sufficient to install the shut-off and control and thermostatic armature only in the singular. Secondly, fewer pipes are needed to connect the convectors. In addition, the length of low-height convectors is greater than the length of 500 mm building-height radiators of the same heat output.

With an estimated water temperature in the heating system of 95-70 ° C and a water speed of 0.4 m / s, the amount of heat passing through a pipe ∅ 20 mm will be about 15.4 kW, at a speed of 0.2 m / s - 7.7 kW.

In this case, the pressure loss due to friction will be about 145 and 39 Pa per linear meter, respectively.

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