Temperature graph for the supply of coolant to the heating system. Heating schedule for quality regulation of heat supply based on the average daily outdoor temperature

The basis of an economical approach to energy consumption in a heating system of any type is the temperature graph. Its parameters indicate optimal value heating water, thereby optimizing costs. In order to apply these data in practice, it is necessary to learn more about the principles of its construction.

Terminology

Temperature graph - the optimal value of heating the coolant to create a comfortable temperature in the room. It consists of several parameters, each of which directly affects the quality of the entire heating system.

The temperature in the inlet and outlet pipes of the heating boiler.
The difference between these indicators of heating the coolant.
Temperature indoors and outdoors.

The latter characteristics are decisive for the regulation of the first two. Theoretically, the need to increase the heating of water in the pipes comes with a decrease in the temperature outside. But how much should be increased so that the heating of the air in the room is optimal? To do this, draw up a graph of the dependence of the parameters of the heating system.

When calculating it, the parameters of the heating system and the residential building are taken into account. For centralized heating, the following temperature parameters of the system are accepted:

150°C/70°C. Before reaching the users, the coolant is diluted with water from the return pipe to normalize the incoming temperature.
90°C/70°C. In this case, there is no need to install equipment for mixing streams.

According to the current parameters of the system, utilities must monitor compliance with the heating medium heating value in the return pipe. If this parameter is less than normal, it means that the room is not warming up properly. The excess indicates the opposite - the temperature in the apartments is too high.

Temperature chart for a private house

The practice of drawing up such a schedule for autonomous heating is not very developed. This is due to its fundamental difference from the centralized one. It is possible to control the water temperature in the pipes in manual and automatic mode. If the installation of sensors for automatic control of the operation of the boiler and thermostats in each room was taken into account during the design and practical implementation, then there will be no urgent need to calculate the temperature schedule.

But for calculating future expenses depending on weather conditions, it will be indispensable. In order to make it according to the current rules, the following conditions must be taken into account:

Only after these conditions are met, you can proceed to the calculation part. At this stage, difficulties may arise. The correct calculation of an individual temperature graph is a complex mathematical scheme that takes into account all possible indicators.

However, to facilitate the task, there are ready-made tables with indicators. The following are examples of the most common operating modes heating equipment. The following input data were taken as initial conditions:

The minimum air temperature outside is 30°С
The optimum room temperature is +22°C.

Based on these data, schedules were drawn up for the following types of heating systems.

It is worth remembering that these data do not take into account the design features of the heating system. They only show the recommended values \u200b\u200bof the temperature and power of heating equipment, depending on weather conditions.

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 requirements for the temperature of the coolant are set out in normative documents that establish the design, installation and use engineering systems residential and public buildings. They are described in the State building codes and regulations:

DBN (B. 2.5-39 Heat networks);
SNiP 2.04.05 "Heating, ventilation and air conditioning".

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

For individual heating to decide what should be the temperature of the coolant, should be taking into account such factors:

The beginning and end of the heating season according to the average daily temperature outside +8 ° C for 3 days;
The average temperature inside heated premises of housing and communal and public importance should be 20 ° C, and for industrial buildings 16 ° C;
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), the coolant limit values are as follows:

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

To calculate the optimal indicators, special graphs and tables can be used, in which the norms are determined depending on the season:

With an average value outside the window of 0 °С, the supply for radiators with different wiring is set at a level of 40 to 45 °С, and the return temperature is from 35 to 38 °С;
At -20 °С, the supply is heated from 67 to 77 °С, while the return rate should be from 53 to 55 °С;
At -40 ° C outside the window for all heating devices set the maximum allowed values. At the supply it is from 95 to 105 ° C, and at the return - 70 ° C.

Optimal values in an individual heating system

H2_2

Autonomous heating helps to avoid many problems that arise with a centralized network, and optimum temperature The coolant can be adjusted according to the season. In the case of individual heating, the concept of norm 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 provided design features heating appliances.

It is important to ensure that the heat carrier in the network does not cool below 70 °C. 80 °C is considered optimal. It is easier to control heating with a gas boiler, because manufacturers limit the possibility of heating the coolant to 90 ° C. Using sensors to adjust the gas supply, the heating of the coolant can be controlled.

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. At the same time, the control of heating of the coolant is rather conditional with high errors and is performed by rotary thermostats and mechanical dampers.

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

One-pipe and two-pipe lines

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

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

Matching the temperature of the heat carrier and the boiler

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

The return temperature depends on the amount of liquid passing through it. The regulators cover the liquid supply and increase the difference between the return and supply to the level that is needed, and the necessary pointers are installed on the sensor.

If it is necessary to increase the flow, then 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 transferred from the return to the inlet.

The regulator redistributes the supply and return flows according to the data taken by the sensor, and ensures strict temperature norms heating networks.

Ways to reduce heat loss

The above information can be used to correct calculation coolant temperature standards and tell you how to determine the situation when you need to use the regulator.

But it is important to remember that the temperature in the room is affected not only by the temperature of the coolant, outdoor 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 the heat loss of housing, you need to worry about its maximum thermal insulation. Insulated walls, sealed doors, metal-plastic windows help reduce heat loss. It will also reduce heating costs.

From a series of articles "What to do if it's cold in the apartment"

What is a temperature chart?

The water temperature in the heating system must be maintained depending on the actual outdoor temperature according to the temperature schedule, which is developed by heat engineers of design and energy supply organizations according to a special methodology for each source of heat supply, taking into account specific local conditions. These schedules should be developed on the basis of the requirement that during the cold season in the living rooms the optimum temperature * is maintained, equal to 20 - 22 ° C.

When calculating the schedule, heat losses (water temperatures) in the area from the heat supply source to residential buildings are taken into account.

Temperature graphs should be drawn up both for the heating network at the outlet of the heat supply source (boiler house, CHP), and for pipelines after the heating points of residential buildings (groups of houses), i.e. directly at the entrance to the heating system of the house.

From heat supply sources to heating network hot water is supplied according to the following temperature charts:*

from large CHP plants: 150/70°С, 130/70°С or 105/70°С;
from boiler houses and small CHP plants: 105/70°С or 95/70°С.

*the first digit is the maximum temperature of the direct supply water, the second digit is its minimum temperature.

Other temperature schedules may be applied depending on specific local conditions.

So, in Moscow, at the exit from the main sources of heat supply, schedules of 150/70°С, 130/70°С and 105/70°С (maximum/minimum water temperature in the heating system) are used.

Until 1991, such temperature charts annually before the autumn-winter heating season were approved by the administrations of cities and other settlements, which was regulated by the relevant regulatory and technical documents (NTD).

Subsequently, unfortunately, this norm disappeared from the NTD, everything was given to the owners of boiler houses, thermal power plants, and other factories - steamships, who at the same time did not want to lose profits.

However, the regulatory requirement for the mandatory compilation of temperature heating schedules has been restored. federal law No. 190-FZ of July 27, 2010 "On heat supply". Here is what is regulated in FZ-190 according to temperature chart(the articles of the Law are arranged by the author in their logical sequence):

“... Article 23. Organization of the development of heat supply systems for settlements, urban districts
…3. Authorized ... bodies [see. Art. 5 and 6 FZ-190] should develop, statement and annual update* * heat supply schemes, which should contain:
…7) Optimal temperature chart…
Article 20. Checking readiness for the heating season
…5. Check readiness for heating period of heat supply organizations ... is carried out in order to ... readiness of these organizations to fulfill the schedule of heat loads, maintaining the temperature schedule approved by the heat supply scheme…
Article 6
1. The powers of local self-government bodies of settlements, urban districts for the organization of heat supply in the respective territories include:
…4) fulfillment of requirements, established rules assessing the readiness of settlements, urban districts for the heating period, and readiness control heat supply organizations, heat network organizations, certain categories of consumers for the heating season;
…6) approval of heat supply schemes settlements, urban districts with a population of less than five hundred thousand people ...;
Article 4, paragraph 2. To the powers of the fed. organ isp. authority authorized to implement the state. heating policies include:
11) approval of heat supply schemes for settlements, mountains. districts with a population of five hundred thousand or more ...
Article 29. Final provisions
…3. Approval of heat supply schemes for settlements ... must be carried out before December 31, 2011.”

And here is what is said about the temperature graphs of heating in the "Rules and norms for the technical operation of the housing stock" (approved by the Post. Gosstroy of the Russian Federation of September 27, 2003 No. 170):

“…5.2. Central heating
5.2.1. System operation central heating residential buildings should provide:
- maintaining the optimum (not below the permissible) air temperature in heated rooms;
- maintaining the temperature of the water entering and returning from the heating system in accordance with the schedule quality regulation water temperature in the heating system (Appendix N 11);
- uniform heating of all heating devices;
5.2.6. The premises of the operating personnel should have:
... e) a graph of the temperature of the supply and return water in the heating network and in the heating system, depending on the outdoor temperature, indicating the operating water pressure at the inlet, the static and maximum allowable pressure in the system; ... "

Due to the fact that a heat carrier with a temperature not higher than can be supplied to house heating systems: for two-pipe systems - 95 ° С; for single-pipe - 105 ° С, at heating points (individual house or group for several houses), before water is supplied to houses, hydraulic elevator units are installed in which direct network water having high temperature, mixed with chilled return water returning from the heating system of the house. After mixing in the hydraulic elevator, the water enters the house system with a temperature according to the "house" temperature chart 95/70 or 105/70 ° С.

The following, as an example, shows the temperature graph of the heating system after heating point residential building for radiators according to the top-down and bottom-up scheme (at intervals outdoor temperature 2 °С), for a city with an estimated outdoor air temperature of 15 °С (Moscow, Voronezh, Orel):

WATER TEMPERATURE IN DISCHARGE PIPELINES, deg. C

AT DESIGN OUTSIDE AIR TEMPERATURE

current outdoor temperature,	water supply to radiators
"upwards"	"top down"
server	back	server	back

Explanations:
1. In gr. 2 and 4 show the values of the water temperature in the supply pipeline of the heating system:
in the numerator - at a calculated water temperature drop of 95 - 70 °C;
in the denominator - with a calculated difference of 105 - 70 °C.
In gr. 3 and 5 show the water temperatures in the return pipeline, which coincide in their values with calculated differences of 95 - 70 and 105 - 70 °C.

Temperature graph of the heating system of a residential building after a heat point

Source: Rules and Regulations technical operation housing stock, adj. twenty
(approved by order of the Gosstroy of the Russian Federation of December 26, 1997 No. 17-139).

Since 2003 they have been operating "Rules and norms for the technical operation of the housing stock"(approved by the Post. Gosstroy of the Russian Federation of September 27, 2003 No. 170), adj. eleven.

Current temperature- outdoor tour	The design of the heater
radiators	convectors
water supply scheme for the device	convector type
		"top down"
water temperature in distributing pipelines, deg. C
	back	serving	back	serving	back	serving	back	serving	back

DESIGN OUTDOOR TEMPERATURE

The normative water temperature in the heating system depends on the air temperature. Therefore, the temperature graph for the supply of coolant to the heating system is calculated in accordance with weather conditions. In the article we will talk about the requirements of SNiP for the operation of the heating system for objects for various purposes.

from the article you will learn:

In order to economically and rationally use energy resources in the heating system, the heat supply is tied to the air temperature. The dependence of the water temperature in the pipes and the air outside the window is displayed as a graph. The main task of such calculations is to maintain comfortable conditions for residents in apartments. For this, the air temperature should be about + 20 ... + 22ºС.

The temperature of the coolant in the heating system

The stronger the frost, the faster the living quarters heated from the inside lose heat. To compensate for the increased heat loss, the temperature of the water in the heating system increases.

In the calculations, a standard temperature indicator is used. It is calculated according to a special methodology and entered into the governing documentation. This indicator is based on average temperature 5 coldest days of the year The calculation is based on the 8 coldest winters over a 50-year period.

Why is the drawing up of a temperature schedule for the supply of coolant to the heating system happening in this way? The main thing here is to be ready for the most severe frosts that happen every few years. Climatic conditions in a particular region can change over several decades. This will be taken into account when recalculating the schedule.

The value of the average daily temperature is also important for calculating the margin of safety of heating systems. With an understanding of the ultimate load, it is possible to accurately calculate the characteristics of the required pipelines, stop valves and other elements. This saves on the creation of communications. Given the scale of construction for urban heating systems, the amount of savings will be quite large.

The temperature in the apartment directly depends on how much the coolant is heated in the pipes. In addition, other factors also matter here:

air temperature outside the window;
wind speed. With strong wind loads, heat losses through doorways and windows increase;
the quality of sealing joints on the walls, as well as the general condition of the decoration and insulation of the facade.

Building codes change as technology advances. This is reflected, among other things, in the indicators in the graph of the coolant temperature depending on the outside temperature. If the premises retain heat better, then energy resources can be spent less.

Developers in modern conditions more carefully approach the thermal insulation of facades, foundations, basements and roofs. This increases the value of objects. However, along with the growth of construction costs are reduced. The overpayment at the construction stage pays off over time and gives good savings.

The heating of the premises is directly affected not even by how hot the water in the pipes is. The main thing here is the temperature of the heating radiators. It is usually in the range of + 70 ... + 90ºС.

Several factors affect battery heating.

1. Air temperature.

2. Features of the heating system. The indicator indicated in the temperature chart for supplying coolant to the heating system depends on its type. AT single pipe systems heating of water up to + 105ºС is considered normal. Two-pipe heating due to better circulation gives a higher heat transfer. This allows you to reduce the temperature to + 95ºС. Moreover, if at the inlet the water needs to be heated, respectively, to + 105ºС and + 95ºС, then at the outlet its temperature in both cases should be at the level of + 70ºС.

So that the coolant does not boil when heated above + 100ºС, it is supplied to the pipelines under pressure. Theoretically, it can be quite high. This should provide a large supply of heat. However, in practice, not all networks allow water to be supplied under great pressure due to its wear and tear. As a result, the temperature drops, and during severe frosts there may be a lack of heat in apartments and other heated premises.

3. The direction of the water supply to the radiators. At the top wiring, the difference is 2ºС, at the bottom - 3ºС.

4. Type of heaters used. Radiators and convectors differ in the amount of heat they give off, which means that they must work in different temperature conditions. Better performance heat transfer from radiators.

At the same time, the amount of heat released is affected, among other things, by the temperature of the outdoor air. It is she who is the determining factor in the temperature schedule for supplying coolant to the heating system.

When the water temperature is +95ºС, we are talking about the coolant at the entrance to the dwelling. Given the heat loss during transportation, the boiler room should heat it much more.

In order to supply water of the required temperature to the heating pipes in the apartments, a special equipment. It mixes hot water from the boiler room with the one that comes from the return.

Temperature chart for supplying coolant to the heating system

The graph shows what the water temperature should be at the entrance to the dwelling and at the exit from it, depending on the street temperature.

The presented table will help to easily determine the degree of heating of the coolant in the central heating system.

Temperature indicators of air outside, ° С	Temperature indicators of water at the inlet, ° С	Temperature indicators of water in the heating system, ° С	Temperature indicators of water after the heating system, ° С

Representatives of utilities and resource-supplying organizations measure the water temperature using a thermometer. The 5th and 6th columns indicate the figures for the pipeline through which the hot coolant is supplied. 7 column - for the return.

The first three columns indicate elevated temperatures - these are indicators for heat generating organizations. These figures are given without taking into account heat losses that occur during the transportation of the coolant.

The temperature schedule for supplying coolant to the heating system is needed not only by resource-supplying organizations. If the actual temperature differs from the standard one, consumers have reasons to recalculate the cost of the service. In their complaints, they indicate how warm the air in the apartments is. This is the easiest parameter to measure. Inspecting authorities can already track the temperature of the coolant, and if it does not comply with the schedule, force the resource supplying organization to perform its duties.

A reason for complaints appears if the air in the apartment cools below the following values:

in corner rooms daytime- below +20ºС;
in the central rooms in the daytime - below + 18ºС;
in corner rooms at night - below +17ºС;
in the central rooms at night - below +15ºС.

SNiP

Requirements for the operation of heating systems are fixed in SNiP 41-01-2003. Much attention in this document is given to security issues. In the case of heating potential danger carries a heated coolant, which is why its temperature for residential and public buildings limited. It, as a rule, does not exceed + 95ºС.

If the water in the internal pipelines of the heating system is heated above + 100ºС, then the following safety measures are provided for at such facilities:

heating pipes are laid in special mines. In the event of a breakthrough, the coolant will remain in these reinforced channels and will not be a source of danger to people;
pipelines in high-rise buildings have special structural elements or devices that do not allow water to boil.

If the building has heating made of polymer pipes, then the temperature of the coolant should not exceed + 90ºС.

We have already mentioned above that in addition to the temperature schedule for supplying coolant to the heating system, responsible organizations need to monitor how hot the accessible elements of heating devices are. These rules are also given in SNiP. Permissible temperatures vary depending on the purpose of the room.

First of all, everything here is determined by the same security rules. For example, in children's and medical institutions allowable temperatures are minimal. In public places and at various production facilities, there are usually no special restrictions for them.

Surface of heating radiators general rules should not be heated above +90ºС. If this figure is exceeded, Negative consequences. They consist, first of all, in the burning of paint on batteries, as well as in the combustion of dust in the air. This fills the indoor atmosphere with substances harmful to health. In addition, there may be harm to appearance heating appliances.

Another issue is safety in rooms with hot radiators. As a general rule, it is necessary to protect heating appliances whose surface temperature is above +75ºС. Usually, lattice fences are used for this. They do not interfere with air circulation. At the same time, SNiP provides for mandatory protection of radiators in children's institutions.

In accordance with SNiP, the maximum temperature of the coolant varies depending on the purpose of the room. It is determined both by the characteristics of the heating of different buildings, and by security considerations. For example, in hospitals allowable temperature water in the pipes is the lowest. It is + 85ºС.

The maximum heated coolant (up to +150ºС) can be supplied to the following facilities:

lobbies;
heated pedestrian crossings;
landings;
technical premises;
industrial buildings, in which there are no aerosols and dust prone to ignition.

The temperature schedule for supplying coolant to the heating system according to SNiP is used only in the cold season. In the warm season, the document in question normalizes the microclimate parameters only in terms of ventilation and air conditioning.