Norms and optimal values ​​of coolant temperature. Optimal operating mode of a wall-mounted gas boiler Optimal coolant temperature for gas boilers

The efficiency of a heating system depends on many factors. These include rated power, heat transfer rate of radiators and temperature regime work. For the last indicator, it is important to correctly select the degree of heating of the coolant. Therefore, it is necessary to determine the optimal temperature in the heating system for water, radiators and boiler.

What determines the temperature of water in heating

For proper operation heating system requires a graph of water temperature in the heating system. According to it, the optimal degree of heating of the coolant is determined depending on the influence of certain external factors. From it you can determine what temperature of water in the heating radiators should be during a certain period of time the system is operating.

A common misconception is that the higher the degree of heating of the coolant, the better. However, this increases fuel consumption and increases operating costs.

Often, the low temperature of radiators is not a violation of room heating standards. A low-temperature heating system was simply designed. That is why the accurate calculation of water heating should be given Special attention.

Optimal temperature water in heating pipes largely depends on external factors. To determine it, you need to take into account the following parameters:

• Heat loss at home. They are decisive for the calculation of any type of heat supply. Their calculation will be the first stage of heat supply design;
• Boiler characteristics. If the operation of this component does not meet the design requirements, the temperature of the water in the heating system of a private house will not rise to the required level;
• Material for making pipes and radiators. In the first case, it is necessary to use pipes with a minimum thermal conductivity. This will reduce heat losses in the system during transportation of coolant from the boiler heat exchanger to the radiators. For batteries, the opposite is important - high thermal conductivity. Therefore, the water temperature in the radiators central heating, made of cast iron, should be slightly higher than that of aluminum or bimetallic structures.

Is it possible to independently determine what temperature should be in the heating radiators? This depends on the characteristics of the system components. To do this, you should familiarize yourself with the properties of the batteries, boiler and heat supply pipes.

IN centralized system heating supply, the temperature of the heating pipes in the apartment is not an important indicator. It is important that air heating standards are observed in living rooms.

Heating standards in apartments and houses

In fact, the degree of heating of water in heating pipes and radiators is a subjective indicator. It is much more important to know the heat transfer of the system. It, in turn, depends on what minimum and maximum water temperatures in the heating system can be achieved during operation.

For autonomous heat supply, central heating standards are quite applicable. They are set out in detail in Resolution of the PRF No. 354. It is noteworthy that the minimum water temperature in the heating system is not indicated there.

It is only important to observe the degree of heating of the air in the room. Therefore, in principle, the operating temperature of one system may be different from another. It all depends on the influencing factors mentioned above.

In order to determine what temperature should be in the heating pipes, you should familiarize yourself with the current standards. Their contents include a division into residential and non-residential premises, as well as the dependence of the degree of air heating on the time of day:

• In the rooms during the daytime. In this case, the standard heating temperature in the apartment should be +18°C for rooms in the middle of the house and +20°C in the corner ones;
• In living rooms at night. Some reduction is allowed. But at the same time, the temperature of the heating radiators in the apartment should provide +15°C and +17°C, respectively.

Responsible for compliance with these standards Management Company. If they are violated, you can request a recalculation of payment for heating services. For autonomous heat supply, a table of temperatures for heating is made, where the values ​​of heating of the coolant and the degree of load on the system are entered. However, no one bears responsibility for violating this schedule. This will affect the comfort of staying in a private home.

For centralized heating, it is mandatory to maintain the required level of air heating in staircases and non-residential premises. The water temperature in the heating radiators should be such that the air is heated to a minimum value of +12°C.

Calculation of heating operating temperature conditions

When calculating heat supply, it is necessary to take into account the properties of all components. This is especially true for radiators. What is the optimal temperature for heating radiators – +70°C or +95°C? It all depends on the thermal calculation, which is performed at the design stage.

First, it is necessary to determine the heat losses in the building. Based on the data obtained, a boiler with the appropriate power is selected. Then comes the most difficult design stage - determining the parameters of the heat supply batteries.

They must have a certain level of heat transfer, which will affect the temperature chart of the water in the heating system. Manufacturers indicate this parameter, but only for a certain operating mode of the system.

If to maintain a comfortable level of air heating in a room you need to spend 2 kW of thermal energy, then the radiators must have a no less heat transfer rate.

To determine this, you need to know the following quantities:

• The permissible maximum water temperature in the heating system ist1. It depends on the boiler power, temperature limit effects on pipes (especially polymer ones);
• Optimal the temperature that should be in the heating return pipes - t This is determined by the type of pipeline layout (one-pipe or two-pipe) and the total length of the system;
• The required degree of heating of the air in the room ist.

Tnap=(t1-t2)*((t1-t2)/2-t3)

Q=k*F*Tnap

Where k– heat transfer coefficient of the heating device. This parameter must be indicated in the passport; F– radiator area; Tnap– thermal pressure.

By varying various indicators of maximum and minimum temperature water in the heating system, you can determine the optimal operating mode of the system. It is important to correctly initially calculate the required power of the heating device. Most often, the low temperature indicator in heating radiators is associated with heating design errors. Experts recommend adding a small margin to the obtained radiator power value - about 5%. This will be needed if the outside temperature drops critically in winter.

Most manufacturers indicate the heat output of radiators according to accepted standards EN 442 for mode 75/65/20. This corresponds to the normal heating temperature in the apartment.

Water temperature in the boiler and heating pipes

After performing the above calculation, it is necessary to adapt the heating temperature table for the boiler and pipes. During operation, heat supply should not occur emergency situations, common cause which is a violation of the temperature schedule.

The normal water temperature in central heating radiators can be up to +90°C. This is strictly monitored at the stage of coolant preparation, its transportation and distribution to residential apartments.

Much the situation is more complicated with autonomous heat supply. In this case, control completely depends on the owner of the house. It is important to ensure that there is no excess temperature of the water in the heating pipes that goes beyond the established schedule. This may affect the safety of the system.

If the water temperature in the heating system of a private home exceeds the norm, the following situations may occur:

• Damage to pipelines. This is especially true for polymer lines, where the maximum heating can be +85°C. That is why the normal temperature of heating pipes in an apartment is usually +70°C. Otherwise, deformation of the line may occur and a gust may occur;
• Excess air heating. If the temperature of the heating radiators in the apartment provokes an increase in the degree of air heating above +27°C, this is outside the normal limits;
• Reduced service life of heating components. This applies to both radiators and pipes. Over time, the maximum water temperature in the heating system will lead to breakdown.

Also, a violation of the water temperature schedule in the autonomous heating system provokes the formation of air jams. This occurs due to the transition of the coolant from liquid to gaseous state. Additionally, this affects the formation of corrosion on the surface of the metal components of the system. That is why it is necessary to accurately calculate what temperature should be in the heat supply batteries, taking into account their material of manufacture.

Most often, a violation of the thermal operating conditions is observed in solid fuel boilers. This is due to the problem of adjusting their power. When a critical temperature level in the heating pipes is reached, it is difficult to quickly reduce the boiler power.

The influence of temperature on the properties of the coolant

In addition to the factors described above, the temperature of the water in the heating pipes affects its properties. This is the basis of the operating principle of gravity heating systems. As the heating level of water increases, it expands and circulation occurs.

However, if antifreeze is used, exceeding the normal temperature in the radiators can lead to different results. Therefore, for heating with a coolant other than water, you should first find out the permissible heating rates. This does not apply to radiator temperatures district heating in the apartment, since such systems do not use antifreeze-based liquids.

Antifreeze is used if there is a possibility that low temperatures will affect radiators. Unlike water, it does not begin to change from a liquid to a crystalline state when it reaches 0°C. However, if the heat supply operation exceeds the norms of the temperature table for heating to a greater extent, the following phenomena may occur:

• Foaming. This entails an increase in the volume of coolant and, as a result, an increase in pressure. The reverse process will not be observed when the antifreeze cools;
• Formation limescale . Antifreeze contains a certain amount of mineral components. If the heating temperature in the apartment is violated, they begin to precipitate. Over time, this will lead to clogged pipes and radiators;
• Increasing the density index. There may be malfunctions circulation pump, unless its rated power was designed to withstand such situations.

Therefore, it is much easier to monitor the water temperature in the heating system of a private home than to control the degree of heating of antifreeze. In addition, when evaporating, ethylene glycol-based compounds emit gas that is harmful to humans. Currently, they are practically not used as a coolant in autonomous systems heat supply.

Before pouring antifreeze into the heating, you should replace all rubber gaskets with paranitic gaskets. This is due to the increased permeability of this type of coolant.

Methods for normalizing heating temperature

The minimum water temperature in the heating system is not the main threat to its operation. This, of course, affects the microclimate in residential premises, but in no way affects the functioning of the heat supply. If the water heating norm is exceeded, emergency situations may occur.

When drawing up a heating scheme, it is necessary to provide a number of measures aimed at eliminating a critical increase in water temperature. First of all, this will lead to an increase in pressure and an increase in load on the inner surface of pipes and radiators.

If this phenomenon is one-time and short-lived, the heat supply components may not be affected. However, such situations arise under the constant influence of certain factors. Most often this is a malfunction of the solid fuel boiler.

• Setting up a security group. It consists of an air vent, a bleed valve and a pressure gauge. If the water temperature reaches a critical level, these components will remove excess coolant, thereby ensuring normal circulation of the liquid for its natural cooling;
• Mixing unit. It connects the return and supply pipes. Additionally, a two-way valve with a servo drive is installed. The latter is connected to the temperature sensor. If the degree of heating exceeds the norm, the valve will open and the flow of hot and cooled water will mix;
• Electronic heating control unit. It records the water temperature in various parts of the system. In the event of a violation of the thermal regime, it will send the appropriate command to the boiler processor to reduce power.

These measures will help prevent incorrect heating operation even further. initial stage occurrence of a problem. It is most difficult to regulate the water temperature level in systems with a solid fuel boiler. Therefore, for them, special attention should be paid to the selection of parameters for the safety group and mixing unit.

The effect of water temperature on its circulation in heating is described in detail in the video:

After installing the heating system, it is necessary to adjust the temperature regime. This procedure must be carried out in accordance with existing standards.

The coolant temperature requirements are set out in regulatory documents that establish the design, installation and use of engineering systems residential and public buildings. They are described in the State Building Codes and Rules:

• DBN (V. 2.5-39 Heat networks);
• SNiP 2.04.05 “Heating, ventilation and air conditioning.”

For the calculated supply water temperature, the figure is taken that is equal to the water temperature at the outlet of the boiler, according to its passport data.

For individual heating deciding what the coolant temperature should be should take into account the following factors:

1. The beginning and end of the heating season based on the average daily outdoor temperature of +8 °C for 3 days;
2. The average temperature inside heated premises of housing, communal and public importance should be 20 °C, and for industrial buildings 16°C;
3. The average design temperature must comply with the requirements of DBN V.2.2-10, DBN V.2.2.-4, DSanPiN 5.5.2.008, SP No. 3231-85.

According to SNiP 2.04.05 “Heating, ventilation and air conditioning” (clause 3.20) limit values coolant are:

Depending on external factors, the water temperature in the heating system can be from 30 to 90 °C. When heated above 90 °C, dust and paintwork begin to decompose. For these reasons sanitary standards more heating is prohibited.

For calculation optimal performance Special graphs and tables can be used that define the norms depending on the season:

• With an average reading outside the window of 0 °C, the supply for radiators with different wiring is set at 40 to 45 °C, and the return temperature at 35 to 38 °C;
• At -20 °C, the supply is heated from 67 to 77 °C, and the return rate should be from 53 to 55 °C;
• At -40 °C outside the window, all heating devices are set to the maximum permissible values. On the supply side it is from 95 to 105 °C, and on the return side it is 70 °C.

Optimal values ​​in an individual heating system

Heating system helps to avoid many problems that arise with a centralized network, and the optimal coolant temperature can be adjusted according to the season. In the case of individual heating, the concept of standards includes the heat transfer of a heating device per unit area of ​​​​the room where this device is located. The thermal regime in this situation is ensured design features heating devices.

It is important to ensure that the coolant in the network does not cool below 70 °C. The optimal temperature is considered to be 80 °C. With a gas boiler, it is easier to control heating, because manufacturers limit the ability to heat the coolant to 90 °C. Using sensors to regulate the gas supply, the heating of the coolant can be adjusted.

It is a little more difficult with solid fuel devices; they do not regulate the heating of the liquid, and can easily turn it into steam. And it is impossible to reduce the heat from coal or wood by turning the knob in such a situation. Control of heating of the coolant is quite conditional with high errors and is carried out by rotary thermostats and mechanical dampers.

Electric boilers allow you to smoothly regulate the heating of the coolant from 30 to 90 °C. They are equipped with an excellent overheat protection system.

Single-pipe and double-pipe lines

The design features of a one-pipe and two-pipe heating network determine different standards for heating the coolant.

For example, for a single-pipe main maximum rate is 105 °C, and for a two-pipe one - 95 °C, while the difference between the return and supply should be respectively: 105 - 70 °C and 95 - 70 °C.

Coordination of coolant and boiler temperatures

Regulators help coordinate the temperature of the coolant and the boiler. These are devices that create automatic control and adjustment of return and supply temperatures.

The return temperature depends on the amount of liquid passing through it. Regulators cover the liquid supply and increase the difference between the return and supply to the level required, and the necessary indicators are installed on the sensor.

If the flow needs to be increased, a boost pump can be added to the network, which is controlled by a regulator. To reduce the heating of the supply, a “cold start” is used: that part of the liquid that has passed through the network is again transported from the return to the inlet.

The regulator redistributes the supply and return flows according to the data collected by the sensor and ensures strict temperature standards heating networks.

Ways to reduce heat loss

The above information will help to be used for correct calculation coolant temperature standards and will tell you how to determine situations when you need to use a regulator.

But it is important to remember that the temperature in the room is affected not only by the temperature of the coolant, street air and wind strength. The degree of insulation of the facade, doors and windows in the house should also be taken into account.

To reduce heat loss from your home, you need to worry about its maximum thermal insulation. Insulated walls, sealed doors, metal-plastic windows will help reduce heat loss. This will also reduce heating costs.

External low-temperature corrosion occurs as a result of the formation of drops or a film of moisture on heating surfaces and reacts with the metal surface.

Moisture appears on heating surfaces during the condensation of water vapor from flue gases due to the low temperature of the water (air) and, accordingly, the low temperature of the wall.

The dew point temperature at which water vapor condenses depends on the type of fuel being burned, its humidity, the excess air coefficient, and the partial pressure of water vapor in the combustion products.

It is possible to eliminate the occurrence of low-temperature corrosion on heating surfaces when the surface temperature on the gas side is 5° C higher than the dew point temperature. This dew point temperature value corresponds to the condensation temperature of pure water vapor and appears during fuel combustion.

When burning fuel (fuel oil) that contains sulfur, sulfuric anhydride is formed in the combustion products. Part of this gas, when oxidized, forms aggressive sulfuric anhydride, which, dissolving in water, forms a film of sulfuric acid solution on the heating surfaces, as a result of which the corrosion process sharply intensifies. The presence of sulfuric acid vapors in combustion products increases the dew point temperature and causes corrosion in those areas of the heating surface whose temperature is significantly higher than the dew point temperature and when burning natural gas it is 55 ° C, when burning fuel oil - 125...150 ° C.

In steam boiler houses, in most cases, the temperature of the water entering the economizer exceeds the required temperature because the water comes from atmospheric deaerators with a temperature of 102 ° C.

This issue is more difficult to solve for hot water boiler houses, since the temperature of the coolant in the external pipeline of the heating system entering the boilers depends on the outside air temperature.

You can increase the temperature of the incoming water to the boiler using recirculation hot water from the boiler.

The efficiency and reliability of the water heating system of a hot water boiler depends on the coolant flow through recirculation. As the pump supply increases, the temperature of the water entering the boiler increases, and the temperature of the exhaust gases also increases, which means the efficiency of the boiler decreases. In this case, the energy consumption for driving the recirculation pump increases.

The operating instructions for hot water boilers propose to regulate the operation of the heating water heating system so that the temperature of the water entering the boilers when burning natural gas does not fall below 60 ° C. This requirement reduces the efficiency of their operation, since anti-corrosion measures can be ensured to maintain the temperature of the walls of the heating surfaces , if the temperature is below 60° C. But in this case, it is necessary to take into account the temperature of the walls of the heating surface in the calculations.

Analysis of this kind of calculations shows that, for example, for hot water boilers operating on natural gas, at a gas temperature of 140 ° C, the water temperature at the entrance to the boiler must be maintained at least 40 ° C, i.e. below 60°C, which is suggested by the instructions.

Thus, by changing the operating mode of hot water boilers, you can save thermal and electrical energy in the absence of low-temperature corrosion metal surfaces hot water boilers.

Hello, friends. What is the optimal operating mode for a gas boiler? There are a number of determining factors here. These are the conditions of its work, its potential, its design, etc.

The main motive for searching for the best regime is economic benefit. At the same time, the equipment must produce maximum efficiency, and consume minimal fuel.

Factors affecting boiler operation

They are:

1. Design. The equipment may have 1 or 2 circuits. It can be mounted on a wall or on the floor.
2. Normative and actual efficiency.
3. Proper heating arrangement. The power of the equipment is comparable to the area that needs to be heated.
4. Technical conditions of the boiler.
5. Gas quality.

All these points need to be optimized so that the device produces the best efficiency,

Question about the design.

The device may have 1 or 2 circuits. The first option is complemented by an indirect heating boiler. The second one already has everything you need. And the key mode in it is ensuring hot water. When water is supplied, heating ends.

Models mounted on the wall have less power than those placed on the floor. And they can heat a maximum of 300 sq.m. If your living space is larger, you will need a floor-mounted unit.

P.2 efficiency factors.

The document for each boiler reflects the standard parameter: 92-95%. For condensation modifications it is approximately 108%. But the actual parameter is usually 9-10% lower. It decreases even more due to heat losses. Their list:

1. Physical underburning. The reason is excess air in the apparatus when gas is burned, and the temperature of the exhaust gases. The larger they are, the more modest the efficiency of the boiler.
2. Chemical underburning. What is important here is the volume of CO2 oxide produced when carbon is burned. Heat is lost through the walls of the apparatus.

Methods for increasing the actual efficiency of a boiler:

1. Removing soot from pipelines.
2. Elimination of scale from the water circuit.
3. Limit chimney draft.
4. Adjust the position of the blower door so that the coolant reaches its maximum temperature.
5. Removing soot from the combustion compartment.
6. Installation of a coaxial chimney.

P.3 Questions about heating. As already noted, the power of the device necessarily correlates with the heating area. A competent calculation is needed. The specifics of the structure and potential heat losses are taken into account. It is better to entrust the calculation to a professional.

If the house is built according to building codes, the formula works: 100 W per 1 sq.m. This results in a table like this:

Purchase better boilers foreign production. Also in advanced versions there are many useful options that help you achieve the optimal mode. One way or another, the optimal power of the device is in the spectrum of 70-75% of the highest value.

Technical conditions. To extend the service life of the device, promptly remove soot and scale from internal parts.

The optimal operating mode of a gas boiler to save gas is achieved by eliminating clocking. That is, you need to set the gas supply to the lowest value. The attached instructions will help with this.

There is an aspect that cannot be influenced - the quality of the gas.

Methods for setting the optimal mode

Many devices are programmed for the temperature of the coolant. When it reaches the required values, the unit turns off briefly. The user can set the temperature himself. The parameters also change depending on the weather. For example, the optimal operating mode of a gas boiler in winter is obtained at values ​​of 70-80 C. In spring and autumn - at 55 - 70 C.

IN modern models There are temperature sensors, thermostats and automatic mode settings.

Thanks to the thermostat, you can set the desired climate in the room. And the coolant will heat up and cool down with a specific intensity. At the same time, the device reacts to temperature changes in the house and outside. This is the optimal operating mode for a floor-standing gas boiler. Although with the help of such devices it is possible to optimize and mounted model. At night, the settings can be reduced by 1-2 degrees.

Thanks to these devices, gas is consumed by 20% less.

If you want solid efficiency and savings from the boiler, purchase the right model. The following are some examples.

Examples of models

1. Baxi.

The optimal operating mode of this wall-mounted gas boiler is achieved as follows: small apartments indicators are set to F08 and F10. The modulation spectrum starts at 40% of the highest power. And the minimum possible operating mode is 9 kW.

Many models of this company are very economical and can operate at low gas pressure. Pressure limits: 9 – 17 mbar. Suitable voltage range: 165 – 240 V.

1. Vaillant.

Many devices of this brand work optimally under the following conditions: power - 15 kW. The feed is set at 50-60. The device works for 35 minutes, rests for 20 minutes.

1. Ferroli.

The best conditions: 13 kW for heating, 24 kW for water heating.

1. Mercury.

Water pressure in the network is maximum 0.1 MPa. The highest temperature indicator at the outlet section is 90 C, the nominal value of the flue gases is at least 110 C. The vacuum behind the apparatus is a maximum of 40 Pa.

1. Navien.

Basically, these are two-circuit units. Automation works here. The mode is customizable. The room heating parameter is set. There is a pump that can reduce parameters by 4-5 degrees.

1. Ariston.

Automatic setting of modes also works. Often people choose models with the Comfort Plus mode.

1. Buderus.

The following values ​​are usually set on the feed: 40 - 82 C. The current parameter is usually reflected on the monitor. The most comfortable summer mode– at 75 C.

Conclusion

Thanks to a gas boiler, you can conveniently adjust the climate in your home. Especially if you use innovative technology with automated modes and many useful options.

A heating boiler is a device that uses the combustion of fuel (or electricity) to heat the coolant.

Device (design) of a heating boiler: heat exchanger, heat-insulated housing, hydraulic unit, as well as safety elements and automation for control and monitoring. Gas and diesel boilers have a burner in their design, while solid fuel boilers have a firebox for wood or coal. Such boilers require a chimney connection to remove combustion products. Electric boilers are equipped with heating elements and do not have burners or a chimney. Many modern boilers are equipped with built-in pumps for forced circulation water.

Operating principle of a heating boiler- the coolant, passing through the heat exchanger, heats up and then circulates through the heating system, releasing the resulting thermal energy through radiators, heated floors, heated towel rails, as well as by heating water in an indirect heating boiler (if it is connected to the boiler).

A heat exchanger is a metal container in which the coolant (water or antifreeze) is heated - can be made of steel, cast iron, copper, etc. Cast iron heat exchangers are resistant to corrosion and quite durable, but are sensitive to sudden temperature changes and are heavy. Steel ones can suffer from rust, so they internal surfaces To increase the service life, they are protected with various anti-corrosion coatings. Such heat exchangers are the most common in the production of boilers. Copper heat exchangers are not susceptible to corrosion and, due to their high heat transfer coefficient, low weight and dimensions, such heat exchangers are popular and are often used in wall-mounted boilers, but usually more expensive than steel ones.
In addition to the heat exchanger, an important part of gas or liquid fuel boilers is the burner, which can be various types: atmospheric or fan, single-stage or two-stage, with smooth modulation, double. ( Detailed description burners are presented in articles about gas and liquid fuel boilers).

To control the boiler, automation is used with various settings and functions (for example, a weather-dependent control system), as well as devices for remote control of the boiler - a GSM module (regulating the operation of the device via SMS messages).

Main technical characteristics heating boilers are: boiler power, type of energy carrier, number of heating circuits, type of combustion chamber, type of burner, type of installation, presence of a pump, expansion tank, boiler automation, etc.

To determine required power heating boiler for a house or apartment, a simple formula is used - 1 kW of boiler power to heat 10 m 2 of a well-insulated room with a ceiling height of up to 3 m. Accordingly, if heating is required basement, glazed winter garden, rooms with non-standard ceilings, etc. The boiler power must be increased. It is also necessary to increase the power (about 20-50%) when providing a boiler and hot water supply (especially if it is necessary to heat the water in the pool).

Let us note a feature of calculating power for gas boilers: the nominal gas pressure at which the boiler operates at 100% of the power declared by the manufacturer, for most boilers is from 13 to 20 mbar, and the actual pressure in gas networks in Russia can be 10 mbar, and sometimes below. Accordingly, a gas boiler often operates at only 2/3 of its capacity and this must be taken into account when calculating. When choosing the boiler power, be sure to note all the features of the thermal insulation of the house and premises. For more details, see the table for calculating the power of a heating boiler.

So which boiler is better to choose? Let's look at the types of boilers:

"Middle class"- average price, not so prestigious, but quite reliable, standard standard solutions are presented. These are Italian boilers Ariston, Hermann and Baxi, Swedish Electrolux, German Unitherm and boilers from Slovakia Protherm.

"Economy class" - budget options, simple models, service life is shorter than that of boilers of a higher category. Some manufacturers have budget boiler models, for example,