In order for any residential building to function normally, it is necessary to install a water supply system. Its proper design will ensure timely supply and sufficient water pressure. This article will discuss in detail the hot water supply diagram, connection types and its features in apartment building.
What is special about the water supply of an apartment building?
It is very difficult to provide water to a building with a large number of storeys. After all, the house consists of many apartments with separate bathrooms and plumbing fixtures. In other words, water supply schemes in apartment buildings are a kind of complex with separate pipe distributions, pressure regulators, filters and metering equipment.
Most often, residents of high-rise buildings use water from the central water supply. With the help of a water supply, it is supplied to individual plumbing fixtures under a certain pressure. Often water is purified using chlorination.
Composition of the central water supply system
Centralized water supply schemes in multi-storey buildings consist of a distribution network, water intake structures and cleaning stations. Before getting into the apartment, water travels a long way from pumping station to the pond. Only after purification and disinfection is water sent to distribution network. With the help of the latter, water is supplied to appliances and equipment. Pipes of the central hot water supply circuit multi-storey building can be made of copper, metal-plastic and steel.
The latter type of material is practically not used in modern buildings.
Types of water supply schemes
There are three types of water supply system:
- collector;
- sequential;
- combined (mixed).
IN lately when in apartments it is increasingly common large number plumbing equipment, use collector wiring diagram . She is the best option normal functioning all devices. The collector-type hot water supply scheme eliminates pressure drops in different points connections. This is the main advantage of this system.
If we consider the diagram in more detail, we can conclude that there will be no problems with using the plumbing equipment for its intended purpose at the same time. The essence of the connection is that each individual water consumer is connected to the cold and hot water supply riser collectors separately. The pipes do not have many branches, so the likelihood of leakage is very low. Such water supply schemes in multi-storey buildings are easy to maintain, but the cost of the equipment is quite high.
According to experts, the collector hot water supply system requires the installation of a more complex installation of plumbing fixtures. However, these negative aspects are not so critical, especially considering the fact that the collector circuit has many advantages, for example - hidden installation pipes and metering individual characteristics equipment.
Sequential hot water supply circuit multi-storey building - this is the easiest way to wire. This system is time-tested; it was put into operation during the Soviet era. The essence of its device is that the cold and hot water supply pipelines are parallel to each other. Engineers advise using this system in apartments with one bathroom and a small amount of plumbing equipment.
Popularly, such a hot water supply scheme for a multi-storey building is called a tee scheme. That is, from the main highways there are branches that are connected to each other by tees. Despite the ease of installation and savings consumables, this scheme has several main disadvantages:
- In the event of a leak, it is difficult to look for damaged areas.
- Inability to supply water to a separate plumbing fixture.
- Difficulty in accessing pipes in case of breakdown.
Hot water supply for an apartment building. Scheme
Pipe connections are divided into two types: to the hot and cold water supply riser. Briefly they are called cold water and hot water. Special attention hot water system deserves apartment building. Scheme DHW networks consists of two types of wiring - lower and upper. To maintain high temperatures in the pipeline, looped wiring is often used. The gravitational pressure forces the water to circulate in the ring, despite the absence of water intake. In the riser it cools and enters the heater. Water with a higher temperature is supplied to the pipes. This is how continuous circulation of the coolant occurs.
Dead-end highways are also not uncommon, but most often they can be found in utility rooms industrial facilities and in small residential buildings with low number of storeys. If water selection is planned intermittently, then a circulation pipeline is used. Engineers advise using hot water supply in apartment buildings (the diagram was discussed above) with a number of floors of no more than 4. A pipeline with a dead-end riser is also found in dormitories, sanatoriums and hotels. Dead-end network pipes have a lower metal consumption and therefore cool faster.
DHW networks include a horizontal main pipeline and distribution risers. The latter provide pipe distribution to individual objects - apartments. DHW is installed as close as possible to plumbing equipment.
For buildings with a large length of main pipes, schemes with circulation and looped supply pipelines are used. Required condition is to install a pump to maintain circulation and constant water exchange.
Two-pipe DHW diagram— Photo 07
Modern builders and engineers are increasingly resorting to using two-pipe systems DHW. The principle of operation is that the pump takes water from the return line and supplies it to the heater. This pipeline has a higher metal consumption and is considered the most reliable for consumers.
When supplying heat, consumers often encounter low quality hot water supply (DHW). Typically complaints about hot water supply are as follows:
· Variable temperature hot water, the temperature changes sharply from hot to cold and vice versa, it is impossible to take a shower.
· The temperature of the hot water is low, it takes a long time to drain the water, or it is even impossible to wait for hot water.
These problems are often associated not with the heat supply source, but with the hot water distribution network in the house. That is, at the entrance to the house there is hot water of the required temperature and pressure, but in the apartment the water parameters do not meet the standards.
Consider the problem with variable hot water temperature. When consuming hot water at the required temperature, for example for taking a shower, it is common to mix cold and hot water. The temperature will be constant provided that the water pressure does not change, but if the water pressure changes, then a change in temperature will occur, that is, the temperature of the mixed water depends on the pressure of the hot and cold water. A sharp change in water temperature is observed due to a sharp change in the pressure of hot and, strange as it may seem, the pressure of cold water. The reason for the change in pressure is a change in flow rate in the supply pipeline and the presence of any “bottlenecks”. “Bottlenecks” include a partially clogged filter at the entrance to the house, a reduced diameter of the filter or water meter, a partially clogged filter at the entrance to the apartment, a “sunk” or clogged valve on the riser. “Bottlenecks” can also include alteration of risers when metal pipe¾ inch (conventional diameter 20 mm) with an internal diameter of 20 mm is replaced with metal-plastic with a diameter of 20 mm with an internal diameter of 16 mm, using fittings with an internal diameter of 14 mm. The cross-section of the riser is reduced by more than 2 times. A significant reduction in pipeline cross-section also occurs on old metal pipelines with a service life of more than 15 years.
Thus, it turns out that neighbors living on different floors, opening cold or hot water taps, draining flush cisterns toilets, change the temperature of each other's mixed water.
Methods to combat this are relatively simple - you need to clean the filters and check the valves on the risers, check whether the house has altered risers public use with decreasing diameters.
The problem with low hot water temperature is more complex because it is related to the quality of the work circulation line DHW. The circulation line is designed to prevent the cooling of water in the pipelines. Circulation is provided by pumps installed in a central heating point (CHS), if hot water is prepared outside the house, or by pumps in an individual heating point (IHP), if hot water is prepared by heat exchangers in the house. The water consumption in the circulation line is lower than the water consumption when consuming hot water, since the task of the circulation line is to “renew” hot water and prevent the water from cooling. The cross-section of the circulation pipelines is much lower; they are designed for constant high consumption, and hot water risers are designed to handle large instantaneous flow rates with the simultaneous consumption of hot water by several consumers.
By wiring device DHW pipelines can be divided into the following types of networks:
o with bottom filling - when the hot water supply pipeline is located in the basement, and the circulation (prefabricated) pipeline is in the attic (technical floor),
o with top filling - when the hot water supply pipeline is located in the attic (technical floor), and the circulation pipeline is in the basement,
o U-shaped - when the hot water riser rises, for example, in kitchens, and descends in bathrooms, the hot water supply pipeline and circulation pipeline are located in the basement.
These types of networks behave differently during operation. As water moves through pipelines, the water cools, becomes denser and tends downwards, so-called natural (gravitational) circulation occurs. In networks with bottom filling natural circulation reduces the circulation created by the pump, and in networks with U-shaped risers and top filling, natural circulation helps the pump.
When the water is turned off top part pipelines enters air and creates air jams, stopping circulation. With U-shaped risers and top filling, air can be removed through water taps, and with bottom distribution, the organization of air collecting tanks in the attic is required. Thus, networks with U-shaped risers and top filling during operation create less problems, but the most common are bottom-filling networks.
The quality of operation of the circulation line is affected by errors made at the stages of design and installation of hot water pipelines. For networks with bottom filling, it is necessary to provide air collecting tanks with automatic air vents, and during installation, observe pipeline slopes to avoid the creation of air pockets.
For normal operation the circulation line needs to be balanced, that is uniform distribution circulation flow through risers. To do this, a washer or balancing valve must be installed at the end of each riser. The cross-section of the washer (valve) must be designed to allow only circulation flow through. The washer (valve) must be installed at the insertion point DHW riser into the circulation line. The diameter of the washer hole can be 3-5 mm, the size of the balancing valve is DN15. Installing a balancing valve is preferable to a washer, since you can quickly change the setting, and if the valve is clogged, you need to open and close it completely to clean it.
Unfortunately, the design does not include the installation of balancing valves and balancing washers. This leads to the fact that circulation occurs only in part of the risers - in the risers closest to the hot water input. Consumers located at the end of the hot water riser and close to the circulation line receive water mainly from the circulation line, where the temperature is obviously 15⁰ lower than in the DHW supply line. If the supply riser is clogged or there is a “bottleneck” in it, then hot water normal temperature it is almost impossible to wait, since water will only come from the circulation line.
The temperature of hot water is also greatly affected by the lack of thermal insulation on distribution pipelines in unheated rooms, the presence of “heating floors” from DHW systems, since the DHW lines are not designed for these additional loads. Missing or malfunctioning check valve on the circulation pipeline at the entrance to the house (or in the ITP) can lead to a decrease in the temperature of hot water during hours of maximum water withdrawal due to the reverse flow of water in the circulation pipeline, mixing circulating water into the hot water.
For normal operation of the DHW system, it is necessary to check the operation of the distribution pipelines and install balancing valves at the junction of the risers with the circulation pipeline. It’s easy to check the operation of the supply riser - you need to close the tap on the circulation pipeline and check whether there is hot water normal pressure and temperature, the absence of water indicates a malfunction of the supply riser. The connection of the riser with the circulation line is checked in the same way - the tap on the supply riser is closed and it is checked whether there is water with the temperature of the circulation line and a low flow rate (with balancing valves or washers installed), the presence of a large flow rate from the tap is evidence of the absence of a balancing valve or washer. Balancing valves are installed instead of shut-off valves of risers.
Conclusions: For normal operation of the DHW system it is necessary:
o No alterations to risers with a reduction in diameter, no “heating floors”, “bottlenecks” on distribution pipelines, presence of slopes and air collecting tanks with air vents,
o Balancing the DHW system by installing balancing valves or washers.
Pipeline for hot centralized water supply cannot be done according to the cold water supply scheme. These pipelines are dead-end, that is, they end at the last water withdrawal point. If you do hot water supply in an apartment building using the same scheme, the water will cool down in the pipeline at night, when it is used little. In addition, there may be such a situation, for example, the residents of a five-story building located on the same riser went to work during the day, the water in the riser was cooling down, and suddenly one of the residents on the fifth floor needed hot water. After turning on the tap, you will first have to drain all the cold water from the riser, wait for warm, and then hot water - this is an excessively high consumption. Therefore, hot water supply pipelines are made in a loop: the water is heated in the boiler room, thermal unit or boiler room and is supplied through the supply pipeline to consumers and returns back to the boiler room through another pipeline, which in this case is called circulation.
IN centralized system For hot water supply, pipelines in the house are laid with two-pipe and single-pipe risers (Fig. 111).
Rice. 111.Distribution diagrams for hot water supply in centralized systems
A two-pipe hot water supply system consists of two risers, one of which supplies water, the other drains it. Place on the outlet circulation riser heating devices- heated towel rails. The water was still heated and served to consumers, but whether they will use it or not and at what time is unknown, so why waste it, let this water warm heated towel rails and the air in damp, by definition, bathrooms. In addition, heated towel rails serve U-shaped compensator for thermal expansion of pipes.
A single-pipe hot water supply system differs from a two-pipe system in that all circulation risers (within one section of the house) were combined into one and this riser was called “idle” (it has no consumers). For better water distribution to individual points of water consumption, as well as in order to maintain the same diameters along the entire height of the building in single-pipe hot water supply systems, the risers are looped. At ring pattern for buildings with a height of up to 5 floors inclusive, the diameters of the risers are 25 mm, and for buildings from 6 floors and above - with a diameter of 32 mm. Single-pipe heated towel rails are placed on supply risers, which means that when low heat water in boiler rooms can reach distant consumers when it has cooled down. Hot water will not only be supplied to nearby consumers, but it will also cool in their heated towel rails. To ensure that the water does not cool down and reaches hot water to distant consumers, a bypass is installed in the heated towel rails.
Two- and one-pipe hot water supply systems can be made without heated towel rails, but then these devices must be connected to the heating system. At the same time, in summer period heated towel rails will not work, and in winter the overall costs for hot water supply and heating will increase.
To ensure air removal from the system, pipes are laid with a slope of at least 0.002 to the pipeline entrance. In systems with bottom wiring, air is removed through the top tap. With top wiring, air is removed through automatic air vents, installed at the highest points of the systems.
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Such a service as DHW circulation exists, and was introduced by Decree of the Government of the Russian Federation of November 8, 2012 N 1149 “On amendments to the Basic Principles of Pricing in the Field of Activities of Public Utilities Organizations.”
In accordance with the review of this document conducted by Garant.ru:
Hot water: tariffs are introduced for open and closed water supply systems. The principles of pricing in the field of activity of public utility organizations have been adjusted. It has been established that regulatory authorities choose the type of tariff (one- or two-part) for cold water, wastewater disposal and treatment waste water established for a specific organization of the public utility complex, in the manner determined methodological instructions. It is also stipulated that these authorities set 2 tariffs for hot water: in a closed hot water supply system and in an open hot water supply (heat supply) system. A closed system is understood as a complex of technologically interconnected engineering structures intended for hot water supply. It can be carried out by taking hot water from hot water supply networks or by heating cold water using a central heating point(without taking hot water from the heating network). In such a system, the hot water tariff consists of a component for cold water and a component for thermal energy. Under open system refers to a technologically connected complex of engineering structures intended for heat supply and hot water supply, carried out by extracting hot water from the heating network. Here, the hot water tariff consists of a coolant component and a thermal energy component. It is stipulated that the surcharge to hot water tariffs is set in the form of a surcharge to the cold water component based on the payment per 1 cubic meter. meter of cold water. In order to establish tariffs for hot water for 2013, the documents provided for by the Rules for regulating tariffs, surcharges and marginal indices in the field of activity of public utility organizations are submitted to regional authorities in the field of regulating tariffs and surcharges before December 1, 2012. The Ministry of Regional Development has been instructed to prepare amendments to the Rules establishing and determining consumption standards utilities. They should establish the procedure for establishing standards for the consumption of utility services, which determines the consumption of thermal energy for heating water for the purpose of hot water supply. Amendments to the Rules that are mandatory when concluding managing organization or HOAs or specialized consumer cooperatives contracts with resource supply organizations. They must establish the procedure for determining the volumes of hot water supplied under a heat supply and (or) hot water supply contract in order to provide hot water supply services.
Hot water supply (HW) networks have much in common with cold water supply networks. The hot water supply network comes with lower and upper wiring. The hot water supply network can be dead-end and looped, but, unlike cold water supply networks, looping the network is necessary to maintain a high water temperature.
Simple (dead-end) hot water networks are used in small low-rise buildings, in domestic premises industrial buildings and in buildings with stable hot water consumption (baths, laundries).
Schemes of hot water supply networks with a circulation pipeline should be used in residential buildings, hotels, dormitories, medical institutions, sanatoriums and rest homes, in children's preschool institutions, as well as in all cases where uneven and short-term water withdrawal is possible.
Typically, a hot water supply network consists of horizontal supply lines and vertical distribution pipelines-risers, from which apartment distribution lines are arranged. Hot water supply risers are laid as close to the appliances as possible.
Figure 1. Diagram with top distribution of the supply line: 1 - water heater; 2 - supply riser; 3 - distribution risers; 4 - circulation network
In addition, hot water supply networks are divided into two-pipe (with looped risers) and single-pipe (with dead-end risers).
Let's look at some of the large number possible schemes of hot water supply networks.
When the lines are routed from the top, the prefabricated circulation pipeline is closed in the form of a ring. The circulation of water in the pipeline ring in the absence of water intake is carried out under the influence of gravitational pressure that arises in the system due to the difference in the density of cooled and hot water. The water cooled in the risers falls down into the water heater and displaces water from it with more high temperature. Thus, continuous water exchange occurs in the system.
Dead-end network diagram(Fig. 2) has the lowest metal consumption, but due to significant cooling and irrational discharge of cooled water, it is used in residential buildings up to 4 floors high, if the risers are not equipped with a heated towel rail and the length of the main pipes is small.
Figure 2. Dead-end hot water supply circuit: 1 - water heater; 2 – distribution risers
If the length of the main pipes is large and the height of the risers is limited, use circuit with looped supply and circulation lines with installation of a circulation pump on them (Fig. 3).
Figure 3. Scheme with looped main pipelines: 1 - water heater; 2 - distribution risers; 3 - diaphragm (additional hydraulic resistance); 4 - circulation pump; 5 - check valve
The most widespread two-pipe scheme(Fig. 4), in which circulation through risers and lines is carried out using a pump that takes water from the return line and supplies it to the water heater. A system with one-sided connection of water points to the supply riser and installation of heated towel rails on the return riser is the most common version of such a scheme. The two-pipe scheme turned out to be reliable in operation and convenient for consumers, but it is characterized by high metal consumption.
Figure 4. Two-pipe hot water supply scheme: 1 - water heater; 2 - supply line; 3 - circulation line; 4 - circulation pump; 5 - supply riser; 6 - circulation riser; 7 - water intake; 8 - heated towel rails
To reduce metal consumption in recent years began to be used a scheme in which several supply risers are combined by a jumper with one circulation riser(Fig. 5).
Figure 5. Scheme with one connecting circulation riser: 1 - water heater; 2 - supply line; 3 - circulation line; 4 - circulation pump; 5 - water risers; 6 - circulation riser; 7 - check valve
Recently appeared diagrams of a single-pipe hot water supply system with one single supply riser per group of water risers(Fig. 6). The idle riser is isolated and installed in pairs with one water riser or in a sectional unit consisting of 2-3 looped water risers. The main purpose of the idle riser is to transport hot water from the main to the upper lintel and then to the water risers. In each riser, independent additional circulation occurs due to the gravitational pressure that arises in the circuit of the sectional unit due to the cooling of water in the water risers. An idle riser helps correct distribution flows within a sectional node.