Closed hot water system. What are hot water systems

A common way to obtain hot water supply (DHW) today is to use the heating network. Two types of heat extraction are used - open and closed. The heated water is delivered to the final consumer through a circular and dead-end pipeline.

You can get hot water from a centralized source or an individual one. In the first case, heated water enters residential buildings and organizations through a heat main, and in the second case, personal water heaters are used for an entrance, a private house or a separate apartment.

The source of heat for heating the main water are thermal stations, boiler houses. In this way, large volumes of water can be pumped, so a centralized pipeline is used to supply apartment buildings and entire neighborhoods. According to the method of extracting heat from the main DHW systems divided into open and closed.

Open heating system

On the streets of cities, you can find pipes of large diameter, wrapped in a heat insulator - this is the heating network. Hot water flows through them, heated at a thermal station. To each, for example, residential building, a branch passes from such a pipe through a substation (TSP). Water enters the system through it. central heating- batteries. In an open system DHW hot water in the faucet in the kitchen or in the bathroom comes from the same source as the battery. The temperature in the DHW system can vary from +50˚С to +75˚С. But in the main it is usually much higher, so it can be mixed with cold water. Such a procedure is technically not always possible, therefore, often, especially cold winter, temperature hot water from the tap is close to critical.

The open method of obtaining hot water is considered the simplest: there is no need for additional elements heating. However, in order to comply sanitary norms often it is necessary to purify water from pollution. Their presence is clearly noticeable when the test heating is turned on for the first time: the water in the hot tap comes the same as that passed through the oxidized after summer downtime batteries. The quality of the resulting water directly depends on the wear heating equipment and the presence of filter elements. Despite this, the open system is quite common due to its massive use in the Soviet era.

Closed heating system

This method also uses a heat pipe, just like the one above. The difference lies in the method of heating: if in open water heated at the CHP and directly enters the house, then when closed it has a separate, dedicated circuit. Purified cold water which passes through the heating heat exchangers. They, in turn, take heat from the main water heated by the CHP. The one that is directly served with open method DHW. Other sources of heat are possible, but the most common is convection, the transfer of heat from an open hot water supply.

With this method, the quality of the water does not depend on the pipes of the central heating. The closed method requires the presence of heat exchangers, additional pumps, which increases the cost when switching from an open type to a closed one. But subsequent savings are also possible due to the stability of the given temperature conditions: in open type often it is necessary to unnecessarily heat the main water due to its separation for heating needs and domestic purposes. Also wins closed system according to organoleptic and bacteriological parameters. The water temperature in the house is always stable and does not depend on the air temperature in winter, as in open method receiving hot water. However, it is not enough to prepare hot water, it must be delivered without loss to houses or apartments. Today, there are two options for filing - circular and dead-end.

Circular feeding method

In it, the heated liquid constantly circulates through vicious circle CHP or boiler house, main line, substation, water supply and back. This was done for a number of reasons, including a large number of subscribers, heat loss during idle water. In practice, this method allows you to get hot water from the tap instantly. It is always on the go and ready to use. When it stops, cooling will occur, which is fraught with heavy losses. In high-rise buildings, this is done by dividing the riser into blocks or additional pumps.

Small difficulties are possible with the circular method: all owners of heated towel rails in the bathroom are aware of the impossibility of reducing their heat in the summer: heated water circulates in them around the clock and all year round. The only way to adjust the temperature of this device will be to install a regulator tap and insert an additional pipe through which the liquid will flow when the tap on the heated towel rail is closed.

Dead end feeding method

Here, the hot water supply system works less efficiently: the consumer has a complete, dead-end water supply. It contains only water supply pipes, devoid of a return circuit. The heated liquid moves when the mixer tap is opened, and when it is closed, the water in the pipe stops and gradually cools. In practice, this means that if the mixer is not used for a long time, in particular at night, cool water will first flow from the tap and only then hot. The dead-end supply method is usually used in private houses connected to the water supply. AT recent times it was the dead-end connection method that became popular due to the spread of individual heaters - boilers.

Local DHW systems

The hot water boiler is an alternative to any DHW system in the absence of it, or a fallback option in case of a traditional summer shutdown. The source of thermal energy is gas or electricity. Also, boilers are divided into flow and storage. In the first case, cold water from the tap is passed through the heater and immediately brought out. The second is more solid, and in it the heated water to the desired temperature is stored in a tank with a capacity of up to 200 liters. It is drained through a conventional mixer, which is connected through a lockable splitter to the boiler and the main hot water supply.

Local hot water systems can also be applied to the entire apartment building on an individual basis. This is sometimes used in new buildings that are equipped with an autonomous heating point. In fact, this is one big boiler for the whole house. Such independent system allows you to save on the transportation of hot water along a long line and virtually eliminates traditional summer shutdowns for routine maintenance.

Whichever hot water system is used, each of them has pros and cons. The quality of hot water can be affected not only by the presence / absence of a dead-end water supply, but also by the pressure of cold water in the main. With its increase and bad job mixer it is sometimes difficult to achieve the perfect balance of cold and hot water at the outlet. If the house often experiences hot water outages, then it is worth purchasing and installing a boiler: its presence will help you comfortably survive the repair of the heating main.

Hot water supply systems can be connected directly (in open heating systems) or independently via water heaters (in closed heating systems). The type of heat supply system (open or closed) is determined during design, and the choice of a particular system is determined by technical and economic indicators.

Direct connection to the supply and return pipelines (a). Hot water of the required temperature is prepared by mixing it with the help of a thermostat from the supply and return pipelines. In the thermostat, the pressure of the water coming from the supply pipeline is throttled to the pressure of the return pipeline (and its amount depends on the temperature of the water in the return pipeline). In accordance with SNiP 41-02-2003 "Heat Networks", the temperature of the heated water at the outlet of the water heater to the hot water supply system should be taken equal to 60 ° C. Therefore, at a temperature in the return pipeline above 60 ° C, the water is completely supplied from the return pipeline , and when the water temperature in it is below 60 ° C - from the return and supply; at a water temperature in the supply pipeline equal to 60 ° C, - completely from it.

At independent accession heating systems (6) leaks are replenished from the hot water supply system after the displacement unit. If the pressure in the return pipeline of the heating network is insufficient to supply water to the hot water supply system, a pressure regulator (backup pressure) is installed with a sufficient total pressure or a booster pump, which can also be a circulation pump. Circulation can be carried out using throttle washers installed on the return pipeline heating system(winter mode) and on the circulation pipeline ( summer mode). In the presence of a pressure regulator (backup), a throttle washer for winter regime do not install.

Direct connection of the hot water system (open circuit)

a - to the supply and return; b - to the supply and return pipelines with independent connection of the heating system;
c - to the return pipeline; g - to the supply pipeline;
1 - mud collector; 2 - temperature controller of mixed water; 3 — controller temperature sensor; 4 - water riser;
5 - circulation pipeline; 6 - elevator of the heating system; 7 - booster circulation pump;
8 - make-up water pipeline; 9 - heating water heater; 10 - circulation pump of the heating system;
11 — throttle washer; 12 - hot water heater; RR - flow regulator; RD - pressure regulator

Direct connection to the return pipeline is shown in fig. c. With a significant flow of water for hot water supply, p\u003e 0.3, the hot water supply system is connected only to the return pipeline, and the water is heated to the standard temperature in the water heater. Such connection makes it possible to reduce the misalignment of the heating system, since the amount of water intake will not affect the water flow in the heating system.

Direct connection to the supply pipeline is shown in fig. d. With this connection, part of the water is taken from the city water supply, heated in a water heater, then mixed with the help of a regulator with water taken from the supply pipeline of the network. The purpose of the scheme is to reduce the consumption of water for hot water supply at the CHPP. However, this loses the main advantage of a system with direct water intake - the protection of the system from internal corrosion. The addition of tap water will corrode the hot water supply of buildings. For this reason, the hot water supply system cannot be connected to the return pipeline to ensure circulation in it, as this will lead to corrosion of the heating network pipelines.

Independent connection with the inclusion of a hot water heater according to parallel circuit. The heating coolant (network water) branches into two parallel flows: one enters the water heater, the other enters the heating system. Therefore, such an inclusion is called parallel. The parallel circuit is used for very small thermal loads of hot water supply in relation to heating (r m< 0,2) или очень больших (р > 1,0).

Turning on a hot water heater in parallel

1 - mud collector; 2 - water heater; 3 - heated water temperature controller;
4 - circulation pump; 5 - distributing pipeline; 6 - water riser;
7 - circulation riser; 8 - circulation pipeline; 9 - heating system;
10 - flow constancy regulator; 11 - elevator

In the absence of storage tanks, due to the uneven consumption of hot water, significant flow fluctuations are observed network water, which affects the parallel connected heating system. Therefore, to stabilize the water flow in the heating system, a constant flow regulator is installed in front of it.

Independent connection with the inclusion of a water heater for hot water supply according to a mixed scheme. The heating coolant (network water) branches into two parallel streams: one enters the II stage water heater, the other enters the heating system. From the heating system, network water enters the water heater of the 1st stage. heated tap water first, it enters stage I, where it is heated by the coolant supplied from the heating system and from the water heater of stage II, and then to stage II until it is heated to the required temperature.

Switching on a hot water heater according to a mixed scheme

1 - mud collector; 2 - temperature controller; 3 - water heater II stage;
4 - flow regulator; 5 - distributing pipeline of the hot water supply system;
6— circulation pipeline; 7 - circulation pumps; 8 - heating system;
9 - elevator; 10 - water heater of the 1st stage

Since one water heater is connected in parallel with the heating system (stage II), and the other in series, this scheme is called mixed. The mixed scheme is applied if p m => 0.2-1, if heat is supplied according to heating schedule or if the heating systems are equipped with elevators with adjustable nozzle. mixed scheme also used when joining public buildings with a ventilation load of more than 15% of the heat consumption for heating. Here, as in the parallel scheme, there are fluctuations in the consumption of network water due to the uneven consumption of hot water. Therefore, to stabilize the water flow in the heating system (in the absence of heat release regulators on it), flow regulators are installed.

Independent connection with the inclusion of water heaters for hot water supply in series.

The heating coolant (network water) passes successively to the II stage hot water heater, then through the heating system and then to the I stage hot water heater. Heated tap water first enters stage I, where it is heated by the coolant supplied through the heating system, and then into stage II for heating to the required temperature. Thus, both hot water heaters and the heating system are connected in series.

The sequential scheme is used at a value of p m \u003d 0.2 - 1 and heat is released according to the total load of heating and hot water supply (increased graph). A distinctive feature of the sequential scheme is the constant flow of network water in heating point, which makes it possible to maintain a stable hydraulic mode in the heating network. The set constant flow rate is maintained by the flow regulator, which changes the flow rate of network water at the jumper, depending on the flow rate for the period of hot water supply.

Turning on the hot water heater in a sequential scheme

1 - sump;, 6 - temperature controller; 3 - water heater II stage; 4 - flow regulator;
5 - distributing pipeline of the hot water supply system; 6 - circulation pipeline;
7 - heating system; 8 - circulation pumps; 9 - elevator; 10 - jumpers for the summer period;
11 - water heater of the 1st stage

Even 20 years ago in private homes, especially in countryside, the installation of autonomous hot water supply was very expensive.

But now everything has become more accessible, already exists big choice relatively inexpensive instruments and equipment for creating such water supply.

There are several types of hot water systems. For example, everyone knows an open and closed hot water supply system. key point at the same time, is right choice equipment that will be used to heat water.

There are various water heaters that differ in their design features, power, power supply. However, all models of water heaters are conditionally divided into flow and storage.

The names of these devices contain their main features. The most practical is considered to be gas-fired water heaters, which have a flow and capacitive type.

Devices are also commonly used indirect heating, which work from the heat that is obtained due to the heating boiler in electric water heaters.

Instantaneous water heaters

They constantly carry out heating of water, in real time, therefore, a constant thermal energy consumption is required. Also instantaneous water heaters can allow you to get hot water almost immediately after the start of work, and stop heating after turning off.

Storage heaters

Their peculiarity is the slowness of heating a given volume, however, they have a fairly low energy consumption. The heated water can be used as needed.

They also work quickly when the tap is opened, and at the same time their power rating will be minimal. The main disadvantage of such devices is their size, which depends on the volume of water needed for heating.

Use of heating boilers

This method of obtaining hot water is quite common.

Single-circuit (heating tap water) and double-circuit (can be used for heating water and for heating) can be used.

Hot water systems

The use of the hot water system is the use special devices for heating cold water, which will be distributed to the water intake elements in the house .

Special water heating equipment heats tap water to the required temperature, and it is supplied to the building using a pump through a pipeline system.

There are several signs by which the separation of hot water systems is carried out.

Based on the scope of use, they can be divided into local and centralized. Local systems are usually used for one or more groups of buildings where consumers heat water. Here, we usually use gas water heaters capacitive and flow types.

Local systems are installed if there is no centralized supply. The main advantage of such a system is the autonomy of work, the independence of repair work(if necessary)

Centralized systems use powerful sources of heat. Getting water using such a system is quite simple and hygienic. However, their use is more complicated, when transporting the coolant to long distances there is a high probability of heat loss.

Based on heat sources, open and closed systems can be used in centralized systems. heating network(heated water is used as a heat carrier) and steam pipelines (mainly used in industrial enterprises).

Open water system

In its design this system hot water supply has a coolant that will circulate in the system.

Hot water is mainly used, which is obtained from centralized system heat supply. The quality of the water in the radiator and in the faucet will be the same. The open system got its name because of the flow of hot water directly from the taps, into which it enters from the heating network.

In urban apartment buildings usually set up an open system. It is not advisable to use such a system in private homes, since a lot of time and money will be spent during installation.

This is also due to the fact that there is no need to use water heating devices.

closed system

A closed hot water supply system is arranged so that the water that is taken from the water supply is cold, after which it enters the heat exchanger, where it heats up, and then enters the tap.

The coolant and hot water are separated from each other. The pipeline through which hot water flows is more prone to corrosion than cold water. Such a system is called closed, since the consumer is supplied not with a coolant, but with heat.

Heat exchangers are located in special points. The water used in this system is only a heat carrier.

After it passes through the heating devices, after giving off its heat, it returns back to be reheated.

Based on the circulation method, systems can be called:

• with forced circulation (pumps are used);
• with natural circulation(the work is carried out at the expense of different density hot and cold water);
• with mixed circulation.

Water supply calculations

The correctness of the calculations should depend on various factors. The amount of water consumed is influenced by the lifestyle and the number of residents, certain norms for hot water supply, through which the water supply is loaded for a certain time.

This means that within the specified time, required amount water, while different places simultaneously. Therefore, these nuances should also be taken into account when calculating the consumed hot water supply.

Even 20 years ago, hot water supply in a private house was just in the dreams of its owner.

Today it is a reality accessible to everyone. The question is only one - which of the systems saves enough water consumption?

The right choice of a hot water supply system will help not only to efficiently heat Vacation home but also significantly save on costs. Sources of hot water supply differ in terms of power, energy consumption and design solutions.

Gas-fired water heaters can use both stored water and flowing water, and are considered the most practical. However, there is an alternative in the form electric heaters. Only by considering the advantages and disadvantages of a particular heating system, you can make the right choice.

All water heaters are divided into flow and storage.

Flow and storage heaters

The principle of their work is as follows. heated running water gives warmth to the room.

A simple example is the standard geyser installed in the private sector of the city.

In its former versions, there is a significant drawback - a lot of water will leak before it heats up.

However, now existing systems gas heating to minimize consumption. (As you know, it is the most optimal heat transfer.) Having spent money on gas heating, you only have to calculate the cost of electricity.

Storage heaters work by storing water. The volume of liquid already in the tank is heated. The power consumption in this case is 1 kW per hour. The advantages of this heater - when turned on, hot water comes out of the tap.

Flaw - big size tank for its accumulation. Here, the owners of small-sized housing are unlikely to be delighted.

Provide hot water Housing is also possible with a heating boiler. Existing species boilers allow not only to have hot water, but also to use it for heating the house. Single-circuit boilers are used only for heating, double-circuit - for heating.

Each system includes devices that evenly distribute heated water along specified coordinates. These are temperature sensors, and a water supply device. The pump supplies a measured amount of it through pipelines, which can also heat the building.

Water supply systems are divided into open and closed.

Open and closed systems - diagrams

In the open provision of hot water at home, the coolant is located directly in the system itself.

Here, the water from the tap and in the radiator is the same in terms of temperature.

And "open" is called because the receipt water is coming immediately through the open taps of the heating system.

An apartment building is supplied with hot water through an open water supply system. Here it is the best option, since there is no need to install and operate water heating equipment.

However, it is practically not suitable for the private sector, since high costs on its installation pay off not soon.

The closed supply system is a means of obtaining clean hot water. Simply put, cold drinking water is heated in the boiler, which enters the house.

You can even use it in cooking, since the obvious disadvantages of an open feed (radiator debris, chemical additives, etc.) are absent here. Closed is good because it does not contain elements harmful to human health.

Calculation of hot water consumption using an example

Consumption calculation

When calculating the consumption of hot water, you need to take into account the number of residents in the house and their lifestyle.

After all, the main requirement for hot water is its minimum period of appearance from the tap.

In addition, according to the existing norms of supply (within 10 minutes), it is supposed to be used not only at several points, but also in unlimited quantities.

Suppose that at the same time in the apartment in the kitchen they wash the dishes and use the shower in the bathroom. Therefore, when calculating the supply of hot water, the following points must be considered:

• Number of water consumers;
• How often do tenants use the bath or shower;
• Number of bathrooms and toilet rooms;
• Volumetric costs of plumbing fixtures (for example, bath volume);
• What temperature of hot water is needed.

Most best option calculation is the use of special instruments for measuring.

However, while this is not possible for everyone. For an approximate calculation without flow sensors, let's take a family of four.

In this situation, when the father fills a bath with a volume of 140 liters, it fills up within 10 minutes, in another bathroom the son takes a shower, spending 30 liters of water. At the same time, mom washes dishes in the kitchen - plus 30 liters.

Adding up all the data, you can understand that in 10 minutes it took 200 liters of hot water.

Of course, the situation is exaggerated and can only be ideal. In reality, consumption is much less.

Only by evaluating the needs of all family members, you can choose the most optimal system domestic hot water supply.