An open hot water supply system is a typical solution for Soviet-era buildings. Differences between open and closed water supply systems

No matter how trite the phrase that you get used to good things quickly sounds, it is true. And indeed, what yesterday was considered something unattainable, today is already taken for granted. This is especially evident in our Everyday life, or rather in the process of arranging our life. So, some 15-20 years ago, autonomous hot water supply for many owners of private houses, especially in rural areas, was considered as something not exclusive and expensive. At the moment, consumers have one problem: how to understand this diversity market supply. After all, hot water supply for general house needs should be arranged not only efficiently, but also economically.

Hot water supply country house can be done in a variety of ways. The main thing is to choose the right equipment for heating water. Water heaters differ in design, power source, power. On the market you can find a huge number of models of these devices, but they all fall into two categories:

flowing;
cumulative.

Already, judging by the names, you can understand functional features each of these types.

Important! The most practical are gas water heaters and capacitive and flow type. There are also devices indirect heating operating on the heat given off by the heating boiler and electric water heaters.

Flow heaters

They heat constantly flowing water and do not have a supply of it. This circumstance places very high demands on them. Everyone knows that water is an extremely heat-consuming substance. For its heating in real time, a huge consumption of thermal energy per unit of time is required. In addition, instantaneous water heating equipment must be brought into operation almost instantly. working condition: turn on - pouring hot water, off – heating is stopped.

Scheme of work of the usual instantaneous water heater

By the way: familiar to many geyser is the clearest example of a flowing gas water heater.

Storage heaters

A given volume of water is heated very slowly, while consuming only 1 kW / hour. Heated water is consumed as needed. They also work instantly when the tap is opened, but at this time the power indicator will have a minimum value. The only drawback of storage water heaters is their overall dimensions. If large volumes of water are needed, then the heating tank must be of impressive size.

Water heating by heating boilers

This is an extremely common way to secure a home. hot water. Heating boilers are of 2 types:

Single-circuit - heat only tap water.
Double-circuit - are used both for heating water and for heating.

Types of hot water systems

Any hot water supply system involves the inclusion of a set of devices designed for heating cold water with its subsequent distribution according to the given water intake elements. Water heaters heat water up to desired temperature. After that, with the help of a pump, it is fed into the building through pipelines. Water supply systems, depending on the method of heating water, can be open and closed.

open system

Open hot water system

An open hot water supply system in its design has a coolant that circulates in the system. The consumer uses hot water coming directly from centralized system heat supply. In this case, the water in the tap and inside the heating radiator will be the same in quality. In other words, people consume coolant. Such a system is called open because hot water is supplied to the consumer through open taps from the heating network. Hot water supply scheme apartment building in most cases, it implies a device, just an open hot water supply system. While in private buildings it will not be optimal due to the high costs of its installation.

Important! This method provision of hot water at home apartment buildings does not provide for the operation of water heating devices, which means that its device is relatively economical.

closed system

The closed hot water supply system is built on the principle that the water taken from the water supply is cold. drinking water, in an additional heat exchanger, it is heated by network water, and only then it goes to the consumer. The heating medium and hot water are separated from each other. Hot water used by people has the same characteristics as cold water from a tap. Hot water pipes corrode faster than cold water pipes. Such a system is called closed because the consumer receives only heat, but not the coolant.

How much hot water do you need?

The calculation of hot water supply depends on many factors that are determined by the lifestyle and the number of residents in a particular room or building. Both in apartments and residential buildings hot water supply is loaded in a short period of time.

Moreover, there are norms for hot water supply according to which about 10 minutes are allotted for a full load. In other words, within 10 minutes, hot water must be available in the required amount, and it can be used simultaneously in several places. For example, in the kitchen, the hostess washes the dishes, while another family member takes a shower in the bathroom. Thus, when calculating hot water supply, it is imperative to take into account the following nuances:

the number of residents;
frequency of using the bathroom, shower;
the number of bathrooms where hot water is used;
specifications plumbing elements (for example, the volume of the bathroom);
expected hot water temperature.

Hot water consumption - approximate calculation

Calculation required amount hot water is possible with measuring instruments

For calculations, we take a standard family consisting of 4 people. We also agree that in 10 minutes a bath with a volume of 140 liters is filled, and at this time a shower is used in another bathroom, consumed about 30 liters of hot water, and finally, dishes are washed in the kitchen - this is another 30 liters. By elementary addition, we calculate that in 10 minutes the water heater must provide water heated to a given temperature in a volume of 200 liters.

Of course, this calculation takes into account ideal conditions hot water consumption. In real life, the value may be less. After all, such an amount of hot water may not be important: you can wait until the water is heated by the heater or use it alternately in different places. Now, after reading our article, realistically assess your needs, make calculations and you can safely proceed to create a hot water system in your home, if one is not available.

It's difficult to imagine comfortable home or apartment without warm water. Proper organization necessary not only for domestic needs, but also is the basis of individual hygiene. A warm morning shower or a relaxing evening bath have become everyday routines. But few people know the specifics of the organization of hot water supply. What is it, what important requirements must be observed when designing a system and how to monitor its condition? To answer these questions, it is necessary to understand the fundamental principles of hot water supply.

What is DHW: tasks and functions

The main function of this system is to provide water with a proper temperature indicator for residential or production premises. In this case, it is necessary to take into account the quality of the liquid, the characteristics of its pressure in the pipes and the method of increasing the temperature to the required value. Depending on the last parameter, the DHW system is divided into 2 types:

Central. Water is heated at thermal substations (CHP) and from them, through pipelines, it is supplied to consumers.
Autonomous. To achieve the required temperature regime, special heating devices are installed - boilers, storage boilers or This type of hot water organization is intended for a small area of \u200b\u200bthe room - an apartment or a house.

Each of them has its own advantages and disadvantages. The central system is more convenient for consumers, but only if its operation is constant and meets temperature standards. Alas, such a situation in our country is more an exception than a rule. Central DHW - what is it, reliable way to provide comfort in the apartment or a "headache" for consumers? This largely depends on the degree of diligence of local regulatory and control bodies.

The autonomous method is more expensive, as it requires the installation of special equipment, gaskets water pipes. However, its performance and degree of comfort far exceeds the central hot water supply. The consumer himself can set the temperature level, control the energy consumption.

hot water requirements

Frequent planned outages and low temperature regime are the main disadvantages of central hot water supply. Such situations occur frequently, but according to current laws, their frequency is strictly regulated. Decree of the Government of the Russian Federation No. 354 defines the following standards:

The composition of water must necessarily comply with sanitary standards SanPiN 2.1.4.2496-09.

To control the flow of the coolant, special devices for hot water supply are installed. Meters are mounted only by representatives managing organization with which an agreement is concluded for the supply of hot water to an apartment or house.

Autonomous systems

The practical implementation of these systems requires a professional approach to each stage of work. For design, you should know the main types of autonomous hot water supply. What it is, and how effectively a certain type will work, depends on the initial technical parameters.

Cumulative

Water is drawn into the storage boiler from external source and then heating it to the desired temperature. DHW scheme this type is applicable to country houses and cottages.

Modern designs of boilers have a number of additional functions:

Several modes of operation - economical, optimal and maximum. It is also possible to delay the start of heating.
The thermal insulation of the case ensures the preservation of heat, which directly affects energy consumption.
A wide range of models that differ depending on the usable volume, functional and operational characteristics.

To achieve the desired temperature level, electric heating elements- heating elements.

flowing

AT apartment buildings popular use of heat-exchange water heaters. Depending on the installed equipment, the following types of devices exist:

flow heaters;
double-circuit heating boilers.

Can be used as energy carriers Electric Energy or thermal, resulting from the combustion of gas. The latter method is preferable, since it is less financially costly and more efficient due to its low inertia.

Regardless of the choice, any DHW system must comply with the standards, perform its direct functions and be absolutely safe for users.

A closed hot water supply system is a set of equipment, pipes and appliances that must solve the problem of heating incoming cold water and then distributing it to consumers. The algorithm for such a system is as follows:

Cold water enters the heater.
The pump delivers the heated water to the pipeline system, through which it enters the consumers.

Basic principles of operation of a closed hot water supply system

The method of heating water determines its type - open or closed. The system during operation of which the consumer receives hot water is called closed. The closed DHW system is based on the following principles:

The water supplied from the water supply enters the additional heater where it receives thermal energy and then served to consumers. In this case, water and coolant are separated from each other. Such a system implies that the hot water supplied to the consumer has the same parameters as the one that flows from the cold water tap.
It should be noted that when using closed system DHW pipes through which hot water is supplied are more susceptible to corrosion.
As part of a closed DHW systems includes two pipelines - supply and return. Through them, water circulates in the system. This allows several consumers to use hot water at the same time without a drop in water pressure. In addition, the closed DHW system is easy to set the temperature.
Such a system allows you to save money, the thing is that it maintains a constant temperature. This is especially true if the building is connected to the system central water supply. By the way, the use of a closed DHW system allows you to connect heated towel rails. But, those who installed a heated towel rail face the following problem - in summer it will be constantly hot, and this will lead to an increase in the temperature in the room. But this problem can be solved by installing shut-off valves that regulate the supply of heated water.

Any water supply system requires calculations of the required amount of hot water. Their results are influenced by certain factors. They are determined primarily by the number of residents living in the house. For calculations, it is necessary to take into account:

predicted water temperature;
the number of residents;
parameters of the used sanitary equipment and a number of others.

Differences between open and closed water supply systems

The use of a closed system implies that the coolant supplied from the heating network will be used to heat the cold water coming from the centralized water supply.

In an open DHW system - hot water is taken directly from the heating network. It is permissible to use it only for domestic needs, for example, for washing dishes or laundry. Such water can have a temperature of up to 75 degrees. It should be noted that the main advantage of a closed DHW system is the quality of the water. As a rule, subject to all design requirements and the absence of violations during its installation, water fully meets the requirements of GOST R 51232-98.

Equipment required for network operation

A closed DHW system is a rather complex engineering and technical system, and a set of certain equipment is required to ensure uninterrupted, and most importantly, safe operation.

Water metering unit

It is through it that water is supplied to the house plumbing. It has a water meter installed. In addition, the design of the unit provides for the possibility of shutting off the water supply during the repair of pipeline fittings, both scheduled and emergency. The composition of the water meter unit is installed:

magnetic or mesh coarse filter;
taps and valves through which cold water is supplied;
measuring instruments - manometers, thermometers;
bypass - a bypass pipeline, which is used during the maintenance of the water meter unit.

Of course, to ensure the operation of the DHW system, a pipe system is involved, it can be divided into three groups:

bottling;
risers;
carts.

Water is transported to the risers through spills located in the basement of the building. Through them, it is supplied directly to the apartments and through the carts it goes to the final consumers - sanitary equipment, Appliances, heated towel rails, etc. There are many schemes for the location of pipes for each group. For example, through risers located in one apartment, water can be supplied to neighboring housing.

Pipe diameters are determined when designing a building, but as a rule, the following dimensions are maintained:

Bottling from 32 to 125 mm;
Risers from 25 to 40 mm;
Eyeliners within 15 - 20 mm.

When developing a project for a closed DHW system, the following materials are laid:

metal-plastic;
pipes made of food grade stainless steel;
galvanized pipes.

When ordering pipes, remember that metal-plastic pipes can be designed for different pressures and different operating temperatures. By the way, during overhaul, dishonest contractors, install pipes that do not meet the requirements of the working documentation, the same applies to pipeline fittings.

The main malfunctions of a closed DHW system

Hot water supply can sometimes fail or work unstably. This is determined by a number of subjective and objective factors. In particular:

errors made during the design and installation of the system;
leaks and noises arising in pipeline fittings. As a rule, this is caused either by wear in the valve gate or by the installation of defective products;
lack of heating of the heated towel rail, most likely it is all caused by air congestion.

As a rule, the water supply system is accepted according to the act, and the company that installed the DHW system for several years must be engaged in warranty service of the transferred management company networks. That is, to eliminate defects in the DHW network, it is necessary to call specialists from the management company or from the contractor company.

Estimated standards for hot water consumption

It should be noted that there are many standards for calculating the consumption of resources; in the housing sector, there are no standards for the use of water per person without the use of a water meter. This is due to the fact that the population density in different regions of our country varies greatly. In other words, each region has its own regulations. In accordance with the rules for locality some water is supplied. At the same time, the size of the volume of water used by the residents of those apartments in which water meters are installed is taken into account.

From the total volume of supplied water, the volume that passed through the metering devices is calculated. The resulting difference is divided by the number of people registered in a given living area. It is these people who bear the cost of the water used. This situation has developed largely because there are many places of unauthorized water consumption and water meters are far from being installed everywhere, by the way, unlike countries with developed economies. Consumption rates are calculated using a multiplying factor.
When making calculations, it is necessary to take into account the condition of plumbing fixtures and the presence of installed water heaters.

The coefficient of consumption consumption in different areas of water is different because in each area water is consumed in different volumes. In this case, it is necessary to take into account the climate, the price of fuel intended for heating water.

The average rate of water consumption per person has been derived. AT daytime this figure is - 200 liters of cold water and 100 liters of hot. An ordinary bathroom holds 250 liters of water, and if the tenant does not take a bath every day, then it makes sense for him to think about installing water meters.

The installed meter will significantly save on paying water bills. The fact is that unauthorized water withdrawals, leaks, water consumption for the needs of the Ministry of Emergency Situations and much more are entered into water bills in one form or another.

A little about the regulatory framework

Any modern man perfectly understands that without the majority utilities, including the availability of hot water, living is not at all comfortable. And often the central water supply system does not always provide consumers with access to hot water. But if you read into normative documentation, namely sanitary norms and rules (SanPiN) 2.1.4.2496-09, then the requirements for the temperature of hot water in a city apartment will become clear. The limiting temperature should not exceed 60 - 75 degrees. This level is mandatory at all consumer connection points. Maintaining this temperature is necessary to prevent the spread of bacterial and other infections that can harm the health of people living in the house.

How often do you call a plumber?

Provide hot water multi-storey building not easy, because in the DHW system there must be water under a certain pressure and at a certain temperature. This is the first. Second: the hot water supply of an apartment building is a long way of the water itself from the boiler house to consumers, in which there is a huge amount of various equipment, devices and appliances. In this case, the connection can be made according to two schemes: with upper or lower wiring.

Network diagrams

So, let's start with the question of how water enters our homes, I mean hot. It moves from the boiler house to the house, and is distilled by pumps installed as boiler equipment. Heated water moves through pipes called heating mains. They can be laid above or below ground. And they must be thermally insulated in order to reduce the heat loss of the coolant itself.

Ring connection diagram

The pipe is brought to apartment buildings, from where the route is branched into smaller sections that supply the coolant to each building. A pipe of smaller diameter enters the basement of the house, where it is divided into sections that deliver water to each floor, and already on the floor to each apartment. It is clear that such an amount of water cannot be consumed. That is, all the water pumped into the hot water supply cannot be consumed, especially at night. Therefore, another route is being laid, which is called the return line. Through it, water moves from the apartments to the basement, and from there to the boiler room through a separately laid pipeline. True, it should be noted that all pipes (both return and supply) are laid along the same route.

That is, it turns out that the hot water itself inside the house moves along the ring. And she is constantly on the move. In this case, the circulation of hot water in an apartment building is carried out precisely from the bottom up and back. But in order for the temperature of the liquid itself to be constant on all floors (with a slight deviation), it is necessary to create conditions under which its speed is optimal, and it does not affect the decrease in the temperature itself.

It should be noted that today separate routes for hot water supply and for heating can approach apartment buildings. Or one pipe with a certain temperature (up to + 95C) will be supplied, which in the basement of the house will be divided into heating and hot water supply.

DHW wiring diagram

By the way, look at the photo above. A heat exchanger is installed in the basement of the house according to this scheme. That is, water from the route is not used in the hot water supply system. It only heats the cold water coming from the water supply network. And the DHW system at home is a separate route, unrelated to the route from the boiler room.

The house network is circulating. And the water supply to the apartments is produced by a pump installed in it. This is by far the most modern scheme. Its positive feature is the ability to control the temperature regime of the liquid. By the way, there are strict norms for the temperature of hot water in an apartment building. That is, it should not be lower than +65C, but not higher than +75C. In this case, small deviations in one direction or another are allowed, but not more than 3C. At night, deviations can be 5C.

Why is this temperature

There are two reasons.

The higher the water temperature, the faster pathogenic bacteria die in it.
But you have to take into account the fact that the high temperature in the DHW system is burns when in contact with water or metal parts of pipes or mixers. For example, at a temperature of +65C, a burn can be obtained in 2 seconds.

Water temperature

By the way, it should be noted that the water temperature in the heating system of an apartment building can be different, it all depends on various factors. But it should not exceed + 95C for two-pipe systems, and + 105C for single-pipe systems.

Attention! According to the legislation, it is determined that if the temperature of the water in the DHW system is 10 degrees below the norm, then the payment is also reduced by 10%. If it is with a temperature of +40 or +45C, then the payment is reduced to 30%.

That is, it turns out that the water supply system of an apartment building, meaning hot water supply, is individual approach payable, depending on the temperature of the coolant itself. True, as practice shows, few people know about this, therefore disputes usually never arise on this issue.

Dead End Schemes

There are also so-called dead-end schemes in the DHW system. That is, water enters consumers, where it cools down if it is not used. Therefore, in such systems there is a very large overrun of the coolant. Such wiring is used either in office premises or in small houses - no more than 4 floors. Although all this is already in the past.

The best option is circulation. And the simplest thing is to enter the pipe into the basement, and from there through the apartments through the riser, which runs through all floors. Each entrance has its own stand. Reaching the top floor, the riser makes a U-turn and, past all the apartments, descends into basement, through which it is output and connected to the return pipeline.

dead end scheme

Wiring in the apartment

So, consider the water supply scheme (HW) in the apartment. In principle, it is no different from cold water. And most often, hot water pipes are laid next to the cold water elements. True, there are some consumers who do not need hot water. For example, a toilet, washing machine or dishwasher. The last two themselves heat the water to the required temperature.

Wiring diagram for hot water and cold water pipes

The most important thing is that the distribution of water supply in the apartment (both hot water supply and cold water) is a certain norm for laying the pipes themselves. For example, if the pipes of two systems are laid one above the other, then the top one should be from hot water supply. If they are laid in a horizontal plane, then the right one should be from the DHW system. In this case, on one wall it may be in the depth of the strobe, and on the other, on the contrary, closer to the surface. In this case, the laying of the pipeline can be hidden (in strobes) or open, laid on the surface of walls or floors.

Conclusion on the topic

The seeming simplicity of hot water supply in apartment buildings is determined by the inhabitants by piping inside the apartments. Actually it's enough big variety various schemes in which pipes are stretched for several kilometers, starting from the boiler room and ending with a mixer in the apartment. And, as practice shows, even in old houses today the hot water supply is being reconstructed for new improved technologies that provide hot water and reduce the loss of heat itself.

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02.10.2013

Open hot water system

This article describes in detail open system hot water supply, its advantages and misses in front of a closed system. The elements of the system under consideration and the principles of its use are named.

Providing hot water is possible thanks to a set of devices that are designed and installed in order to supply process water and water for personal use.

Which hot water system you need to choose depends on several factors - these are the conditions under which water is supplied, the source of energy for heating water, and the quality of both water and plumbing. The use of an open water supply system should be justified from the side of economy and technology.

Considering choice from the outside sanitary norms, then a closed system that is connected to the central city heating network looks more reliable.

But if we talk about local network, then everything is decided by the quality of water and the economic benefits of each system in each particular case.

Types of open systems

The system can have two versions: centralized or decentralized. The difference is that the centralized system provides several consumers (from one building to the whole village). The decentralized system prepares water directly at the point of use, using small heating devices.

One of two types of schemes can be used to supply hot water: with circulating pipelines, or a non-circulating scheme. The non-circulating hot water supply scheme is characterized by its structural simplicity and inexpensive starting cost.

Consider a non-circulating water supply system

When using a non-circulating circuit, there is no need to purchase circulation pump, but at the same time, if you do not use water for a while, then it cools quickly. This means that by opening the tap, the consumer will receive not hot water, but already cooled down, and to get hot water, it is necessary to drain some cool water.

Which is only an inconvenience, increases the waste of water, adds a burden to the drainage system and wastes energy.

open system of this type will be acceptable for use only in a network with a continuous intake of hot water, or in short individual networks.

Circulating water supply system

In places where a constant supply of hot water is necessary, and it is undesirable to drain the water before the intake, circulation systems are used. In this system, water flows continuously through the water heater without stopping or cooling down, maintaining the temperature at the selected level at all points of water consumption.

For buildings with no more than 4 floors, it is necessary to arrange water circulation only in divorced pipes. For taller buildings, water must also circulate through the risers. Moreover, at the points of connection of the centralized system to the local branch, the water must have a temperature of at least 60 ° C for open systems, and at least 50 ° C for closed ones. And, in both cases, should not exceed 75˚С.

What is the difference between open and closed water supply

A closed system is more energy efficient by using the heat from the leaving water to heat the incoming cold water. This process of heat energy exchange takes place in the heat exchanger. Conversely, in open systems, hot water comes directly from the heating network. In this regard, the systems differ and are classified according to the method of water supply.

The use of open systems requires disinfection of the network with chlorine, as well as flushing the system with 90 degrees hot water.

Any water heating device must be periodically cleaned, because at high temperatures adverse conditions are created that greatly affect the quality of the water.

The composition of an open hot water supply system is simple. The system consists of water heating equipment, a pump that circulates water in the system and pipelines through which water is directly supplied to each intake point. The distribution line can be made in two versions:

1. With top wiring - when water heaters and tanks are located on top, which requires a technical floor in the building. The circulation line itself, in this case, is located in the basement.

2. With lower wiring - when the heating equipment is located in the basement, which is more convenient for servicing such a system.

Required water quality

Water in an open system has the same quality as water in radiators. In this connection, the requirements prescribed for the quality of water in an open system are much higher than for water in closed systems, where hot water almost does not differ in quality from the cold supply.

Open system device

All equipment for the device of an open system must be selected taking into account the principle of operation of the system. In other words, the water pressure in the taps of all floors must be absolutely sufficient and practically the same. This is not even always achievable when using a pump with the required capacity.

The force of friction of water against the walls of pipes should be taken into account, which acts as a kind of barrier to the movement of water. At first it seems insignificant, but, as practice shows, an open system works effectively when even the smallest factors of influence are taken into account.

The following factors affect the water pressure:

Geodetic height of water injection;

Dynamic pressure in the pipeline;

Pressure losses in networks.

In such a system, it is convenient to use cranes to cut off individual sections if it is necessary to carry out scheduled maintenance or repairs. Also, it is advisable to use other protective devices, such as the float sensors in tanks and pressure switches in pipes.

System efficiency

As in the general case, the efficiency of the system can be determined by the level of thermal energy output with the lowest energy consumption. Both systems, with zero water intake, will not differ in their efficiency (unless it will be more efficient when using a heat pump).

A closed system can provide hydraulic decoupling of heating networks, while an open system supplies consumers with hot water at a lower cost. Also, it has greater reliability and the possibility of improving the efficiency of work in the future (when using high-quality water).

Note:Quality plastic window depends on the type of glazing used. They are single-chamber, two-chamber heat-saving, noise-insulating, sun-protection and impact-resistant. From all this, the price of the window will differ. In addition, you need to carefully choose stores and familiarize yourself with possible discounts.

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