Temperature graph 130 70 and its parameters. Substantiation of the reduced temperature schedule for regulation of centralized heat supply systems

Looking through the statistics of visits to our blog, I noticed that search phrases such as, for example, appear very often “What should be the temperature of the coolant at minus 5 outside?”. Decided to post the old one. schedule quality regulation heat supply according to the average daily outdoor temperature. I want to warn those who, on the basis of these figures, will try to sort out relations with the housing department or heating networks: the heating schedules for each individual settlement are different (I wrote about this in an article). Thermal networks in Ufa (Bashkiria) operate according to this schedule.

I also want to draw attention to the fact that regulation occurs according to average daily outside temperature, so if, for example, outside at night minus 15 degrees, and during the day minus 5, then the coolant temperature will be maintained in accordance with the schedule minus 10 o C.

As a rule, the following temperature charts are used: 150/70 , 130/70 , 115/70 , 105/70 , 95/70 . The schedule is selected depending on the specific local conditions. House heating systems operate according to schedules 105/70 and 95/70. According to schedules 150, 130 and 115/70, main heat networks operate.

Let's look at an example of how to use the chart. Suppose the temperature outside is minus 10 degrees. Heating network work according to the temperature schedule 130/70 , which means at -10 o С the temperature of the heat carrier in the supply pipeline of the heating network must be 85,6 degrees, in the supply pipeline of the heating system - 70.8 o C with a schedule of 105/70 or 65.3 about C on a 95/70 schedule. The temperature of the water after the heating system must be 51,7 about S.

As a rule, the temperature values ​​in the supply pipeline of heat networks are rounded off when setting the heat source. For example, according to the schedule, it should be 85.6 ° C, and 87 degrees are set at the CHP or boiler house.

Please do not focus on the diagram at the beginning of the post - it does not correspond to the data from the table.

Calculation of the temperature graph

The method for calculating the temperature graph is described in the reference book (Chapter 4, p. 4.4, p. 153,).

This is quite laborious and long process, since for each outdoor temperature several values ​​\u200b\u200bmust be considered: T 1, T 3, T 2, etc.

To our joy, we have a computer and a MS Excel spreadsheet. A colleague at work shared with me a ready-made table for calculating the temperature graph. She was once made by his wife, who worked as an engineer for a group of regimes in thermal networks.

In order for Excel to calculate and build a graph, it is enough to enter several initial values:

• design temperature in the supply pipeline of the heating network T 1
• design temperature in the return pipeline of the heating network T 2
• design temperature in the supply pipe of the heating system T 3
• Outside temperature T n.v.
• Indoor temperature T v.p.
• coefficient " n» (it is usually not changed and is equal to 0.25)
• Minimum and maximum cut of the temperature graph Cut min, Cut max.

All. nothing more is required of you. The results of the calculations will be in the first table of the sheet. It is highlighted in bold.

The charts will also be rebuilt for the new values.

The table also considers the temperature of direct network water, taking into account wind speed.

What laws are subject to changes in the temperature of the coolant in systems central heating? What is it - the temperature graph of the heating system 95-70? How to bring the heating parameters in accordance with the schedule? Let's try to answer these questions.

What it is

Let's start with a couple of abstract theses.

• With change weather conditions heat losses of any building change after them. In frosts, in order to maintain a constant temperature in the apartment, much more thermal energy is required than in warm weather.

To clarify: heat costs are determined not by the absolute value of the air temperature in the street, but by the delta between the street and the interior.
So, at +25C in the apartment and -20 in the yard, the heat costs will be exactly the same as at +18 and -27, respectively.

• The heat flow from the heater at a constant coolant temperature will also be constant.
  A drop in room temperature will slightly increase it (again, due to an increase in the delta between the coolant and the air in the room); however, this increase will be categorically insufficient to compensate for the increased heat loss through the building envelope. Simply because the current SNiP limits the lower temperature threshold in an apartment to 18-22 degrees.

An obvious solution to the problem of increasing losses is to increase the temperature of the coolant.

Obviously, its growth should be proportional to the decrease in street temperature: the colder it is outside the window, the big losses heat will have to be compensated. Which, in fact, brings us to the idea of ​​creating a specific table for matching both values.

So the schedule temperature system heating is a description of the dependence of the temperatures of the supply and return pipelines on the current weather outside.

How it all works

There are two different types charts:

1. For heating networks.
2. For domestic heating system.

To clarify the difference between these concepts, it is probably worth starting with a brief digression into how central heating works.

CHP - heat networks

The function of this bundle is to heat the coolant and deliver it to the end user. The length of heating mains is usually measured in kilometers, the total surface area - in thousands and thousands. square meters. Despite the measures for thermal insulation of pipes, heat losses are inevitable: having passed the path from the CHP or boiler house to the border of the house, process water cool down partially.

Hence the conclusion: in order for it to reach the consumer, while maintaining an acceptable temperature, the supply of the heating main at the exit from the CHP should be as hot as possible. The limiting factor is the boiling point; however, with increasing pressure, it shifts in the direction of increasing temperature:

Typical pressure in the supply pipeline of the heating main is 7-8 atmospheres. This value, even taking into account pressure losses during transportation, allows you to start the heating system in houses up to 16 floors high without additional pumps. At the same time, it is safe for routes, risers and inlets, mixer hoses and other elements of heating and hot water systems.

With some margin, the upper limit of the supply temperature is taken equal to 150 degrees. The most typical heating temperature curves for heating mains lie in the range of 150/70 - 105/70 (supply and return temperatures).

House

There are a number of additional limiting factors in the home heating system.

• The maximum temperature of the coolant in it cannot exceed 95 C for a two-pipe and 105 C for.

By the way: in preschool educational institutions, the restriction is much more stringent - 37 C.
The price of lowering the supply temperature is an increase in the number of radiator sections: in the northern regions of the country, group rooms in kindergartens are literally surrounded by them.

• The temperature delta between the supply and return pipelines, for obvious reasons, should be as small as possible - otherwise the temperature of the batteries in the building will vary greatly. This implies a fast circulation of the coolant.
  However, too fast circulation through house system heating will cause the return water to return to the route with exorbitant high temperature, which is unacceptable due to a number of technical limitations in the operation of the CHPP.

The problem is solved by installing one or more elevator units in each house, in which the return flow is mixed with the water stream from the supply pipeline. The resulting mixture, in fact, ensures the rapid circulation of a large volume of coolant without overheating the return pipeline of the route.

For intra-house networks, a separate temperature graph is set, taking into account the elevator operation scheme. For two-pipe circuits, a heating temperature graph of 95-70 is typical, for single-pipe circuits (which, however, is rare in apartment buildings) — 105-70.

Climate zones

The main factor that determines the scheduling algorithm is the estimated winter temperature. The heat carrier temperature table should be drawn up in such a way that the maximum values ​​\u200b\u200b(95/70 and 105/70) at the peak of frost provide the temperature in residential premises corresponding to SNiP.

Here is an example of an intra-house schedule for the following conditions:

• Heating devices - radiators with a coolant supply from the bottom up.
• Heating - two-pipe, co.

• The estimated outdoor air temperature is -15 C.

Nuance: when determining the parameters of the route and the in-house heating system, average daily temperature.
If it is -15 at night and -5 during the day, as outdoor temperature appear -10C.

And here are some values ​​​​of calculated winter temperatures for Russian cities.

In the photo - winter in Verkhoyansk.

Adjustment

If the management of the CHPP and heating networks is responsible for the parameters of the route, then the responsibility for the parameters of the intra-house network rests with the residents. A very typical situation is when, when residents complain about the cold in apartments, measurements show downward deviations from the schedule. It happens a little less often that measurements in the wells of heat pumps show an overestimated return temperature from the house.

How to bring the heating parameters in line with the schedule with your own hands?

Nozzle reaming

With low mixture and return temperatures, the obvious solution is to increase the diameter of the elevator nozzle. How it's done?

The instruction is at the service of the reader.

1. All valves or gates in the elevator unit are closed (inlet, house and hot water).
2. The elevator is dismantled.
3. The nozzle is removed and reamed by 0.5-1 mm.
4. The elevator is assembled and started with air bleeding in the reverse order.

Tip: instead of paronite gaskets on the flanges, you can put rubber ones cut to the size of the flange from the car chamber.

An alternative is to install an elevator with an adjustable nozzle.

Suction suppression

In a critical situation extreme cold and freezing flats) the nozzle can be completely removed. So that the suction does not become a jumper, it is suppressed with a pancake made of steel sheet with a thickness of at least a millimeter.

Attention: this is an emergency measure, used in extreme cases, since in this case the temperature of the radiators in the house can reach 120-130 degrees.

Differential adjustment

At elevated temperatures as a temporary measure until the end heating season practice is to adjust the differential on the elevator with a valve.

1. The DHW is switched to the supply pipe.
2. A manometer is installed on the return.
   
3. The inlet gate valve on the return pipeline closes completely and then gradually opens with pressure control on the pressure gauge. If you just close the valve, the subsidence of the cheeks on the stem can stop and unfreeze the circuit. The difference is reduced by increasing the return pressure by 0.2 atmospheres per day with daily temperature control.

Conclusion

The temperature graph represents the dependence of the degree of heating of water in the system on the temperature of cold outside air. After the necessary calculations, the result is presented in the form of two numbers. The first means the temperature of the water at the inlet to the heating system, and the second at the outlet.

For example, the entry 90-70ᵒС means that under given climatic conditions, for heating a certain building, it will be necessary that the coolant at the inlet to the pipes has a temperature of 90ᵒС, and at the outlet 70ᵒС.

All values ​​are presented for the outside air temperature for the coldest five-day period. This design temperature is taken according to the joint venture " Thermal protection buildings." According to the norms, the internal temperature for residential premises is 20ᵒС. The schedule will ensure the correct supply of coolant to the heating pipes. This will avoid hypothermia of the premises and waste of resources.

The need to perform constructions and calculations

The temperature schedule must be developed for each settlement. It allows you to provide the most competent work heating systems, namely:

1. Align heat loss at the time of filing hot water in houses with an average daily outdoor temperature.
2. Prevent insufficient heating of rooms.
3. Oblige thermal power plants to supply consumers with services that meet technological conditions.

Such calculations are necessary both for large heating stations and for boiler houses in small settlements. In this case, the result of calculations and constructions will be called the boiler house schedule.

Ways to control the temperature in the heating system

Upon completion of the calculations, it is necessary to achieve the calculated degree of heating of the coolant. You can achieve it in several ways:

• quantitative;
• quality;
• temporary.

In the first case, the flow rate of water entering the heating network, in the second, the degree of heating of the coolant is regulated. The temporary option involves a discrete supply of hot liquid to the heating network.

For central system heat supply is most characteristic of high-quality, while the volume of water entering the heating circuit remains unchanged.

Graph types

Depending on the purpose of the heating network, the execution methods differ. The first option is the normal heating schedule. It is a construction for networks that work only for space heating and are centrally regulated.

The increased schedule is calculated for heating networks that provide heating and hot water supply. It is built for closed systems and shows the total load on the hot water supply system.

The adjusted schedule is also intended for networks operating both for heating and for heating. Here, heat losses are taken into account when the coolant passes through the pipes to the consumer.

Drawing up a temperature chart

The constructed straight line depends on the following values:

• normalized air temperature in the room;
• outdoor air temperature;
• the degree of heating of the coolant when it enters the heating system;
• the degree of heating of the coolant at the outlet of the building networks;
• degree of heat transfer heating appliances;
• thermal conductivity of the outer walls and the overall heat loss of the building.

To perform a competent calculation, it is necessary to calculate the difference between the water temperatures in the direct and return pipes Δt. The higher the value in the straight pipe, the better the heat transfer of the heating system and the higher the indoor temperature.

In order to rationally and economically consume the coolant, it is necessary to achieve the minimum possible value of Δt. This can be achieved, for example, by working on additional insulation external structures of the house (walls, coverings, ceilings over a cold basement or technical underground).

Calculation of the heating mode

First of all, you need to get all the initial data. Standard values temperatures of outdoor and indoor air are taken according to the joint venture "Thermal protection of buildings". To find the power of heating devices and heat losses, you will need to use the following formulas.

Heat loss of the building

In this case, the input data will be:

• the thickness of the outer walls;
• thermal conductivity of the material from which the enclosing structures are made (in most cases it is indicated by the manufacturer, denoted by the letter λ);
• surface area of ​​the outer wall;
• climatic area of ​​construction.

First of all, the actual resistance of the wall to heat transfer is found. In a simplified version, you can find it as a quotient of the wall thickness and its thermal conductivity. If a outdoor structure consists of several layers, individually find the resistance of each of them and add the resulting values.

Thermal losses of walls are calculated by the formula:

Q = F*(1/R 0)*(t inside air -t outside air)

Here Q is the heat loss in kilocalories and F is the surface area of ​​the exterior walls. For more exact value it is necessary to take into account the area of ​​​​the glazing and its heat transfer coefficient.

Calculation of the surface power of batteries

Specific (surface) power is calculated as a quotient of the maximum power of the device in W and the heat transfer surface area. The formula looks like this:

R beats \u003d R max / F act

Calculation of the coolant temperature

Based on the obtained values, temperature regime heating and a direct heat transfer is built. On one axis, the values ​​​​of the degree of heating of the water supplied to the heating system are plotted, and on the other, the outside air temperature. All values ​​are taken in degrees Celsius. The results of the calculation are summarized in a table in which the nodal points of the pipeline are indicated.

It is rather difficult to carry out calculations according to the method. To perform a competent calculation, it is best to use special programs.

For each building, such a calculation is carried out individually by the management company. For an approximate definition of water at the inlet to the system, you can use the existing tables.

1. For large suppliers of thermal energy, coolant parameters are used 150-70ᵒС, 130-70ᵒС, 115-70ᵒС.
2. For small systems for a few apartment buildings parameters apply 90-70ᵒС (up to 10 floors), 105-70ᵒС (over 10 floors). A schedule of 80-60ᵒС can also be adopted.
3. When arranging an autonomous heating system for individual home it is enough to control the degree of heating with the help of sensors, you can not build a graph.

The measures taken make it possible to determine the parameters of the coolant in the system in certain moment time. By analyzing the coincidence of the parameters with the schedule, you can check the efficiency of the heating system. The temperature chart table also indicates the degree of load on the heating system.

Each heating system has certain characteristics. These include power, heat transfer and temperature operation. They determine the efficiency of work, directly affecting the comfort of living in the house. How to choose the right temperature graph and heating mode, its calculation?

Drawing up a temperature chart

The temperature schedule of the heating system is calculated according to several parameters. Not only the degree of heating of the premises, but also the flow rate of the coolant depends on the selected mode. This also affects the ongoing costs of heating maintenance.

The drawn up schedule of the temperature regime of heating depends on several parameters. The main one is the level of water heating in the mains. It, in turn, consists of the following characteristics:

• Temperature in the supply and return pipelines. Measurements are made in the corresponding boiler nozzles;
• Characteristics of the degree of heating of air indoors and outdoors.

The correct calculation of the heating temperature graph begins with the calculation of the difference between the temperature of the hot water in the direct and supply pipes. This value has the following notation:

∆T=Tin-Tob

Where Tin- water temperature in the supply line, Tob- the degree of heating of water in the return pipe.

To increase the heat transfer of the heating system, it is necessary to increase the first value. To reduce the coolant flow rate, ∆t must be kept to a minimum. This is precisely the main difficulty, since the temperature schedule of the heating boiler directly depends on external factors- heat losses in the building, air in the street.

To optimize the heating power, it is necessary to make thermal insulation of the outer walls of the house. This will reduce heat losses and energy consumption.

Temperature calculation

To determine the optimal temperature regime, it is necessary to take into account the characteristics of the heating components - radiators and batteries. In particular, specific power (W / cm²). This will directly affect the heat transfer of heated water to air into the room.

It is also necessary to make a series preliminary calculations. This takes into account the characteristics of the house and heating devices:

• Heat transfer resistance coefficient of external walls and window structures. It must be at least 3.35 m² * C / W. Depends on the climatic features of the region;
• Surface power of radiators.

The temperature curve of the heating system is directly dependent on these parameters. To calculate the heat loss of a house, it is necessary to know the thickness of the outer walls and the building material. The calculation of the surface power of batteries is carried out according to the following formula:

Rud=P/Fact

Where R – maximum power, W, fact– radiator area, cm².

According to the data obtained, a temperature regime for heating and a heat transfer schedule are compiled depending on the temperature outside.

To timely change the heating parameters, a temperature heating controller is installed. This device connects to outdoor and indoor thermometers. Depending on the current indicators, the operation of the boiler or the volume of coolant inflow to the radiators is adjusted.

The weekly programmer is the optimal temperature controller for heating. With its help, you can automate the operation of the entire system as much as possible.

Central heating

For district heating the temperature regime of the heating system depends on the characteristics of the system. Currently, there are several types of parameters of the coolant supplied to consumers:

• 150°C/70°C. To normalize the water temperature with elevator node it is mixed with the cooled stream. In this case, it is possible to draw up an individual temperature schedule for a heating boiler house for a particular house;
• 90°C/70°C. It is typical for small private heating systems designed to supply heat to several apartment buildings. In this case, you can not install the mixing unit.

It is the responsibility of utilities to calculate the temperature heating schedule and control of its parameters. At the same time, the degree of air heating in residential premises should be at the level of + 22 ° С. For non-residential, this figure is slightly lower - + 16 ° С.

For a centralized system, drawing up the correct temperature schedule for the heating boiler room is required to ensure optimal comfortable temperature in apartments. The main problem is the lack feedback- it is impossible to adjust the parameters of the heat carrier depending on the degree of air heating in each apartment. That is why the temperature schedule of the heating system is drawn up.

A copy of the heating schedule can be requested from the Management Company. With it, you can control the quality of the services provided.

Heating system

Do the same calculations for autonomous systems heating of a private house is often not necessary. If the scheme provides for indoor and outdoor temperature sensors, information about them will be sent to the boiler control unit.

Therefore, in order to reduce energy consumption, a low-temperature heating mode is most often chosen. It is characterized by relatively low water heating (up to +70°C) and a high degree of water circulation. This is necessary to evenly distribute heat to all heaters.

To implement such a temperature regime of the heating system, the following conditions must be met:

• Minimum heat loss in the house. However, one should not forget about normal air exchange - ventilation is a must;
• High heat output of radiators;
• Installation automatic regulators heating temperatures.

If there is a need to perform a correct calculation of the system, it is recommended to use special software systems. There are too many factors to consider for self-calculation. But with their help, you can draw up approximate temperature graphs for heating modes.

However, it should be borne in mind that an accurate calculation of the heat supply temperature schedule is done for each system individually. The tables show the recommended values ​​for the degree of heating of the coolant in the supply and return pipes, depending on the temperature outside. When performing calculations, the characteristics of the building, the climatic features of the region were not taken into account. But even so, they can be used as a basis for creating a temperature graph for a heating system.

The maximum load of the system should not affect the quality of the boiler. Therefore, it is recommended to purchase it with a power reserve of 15-20%.

Even the most accurate temperature chart of the heating boiler room will experience deviations in the calculated and actual data during operation. This is due to the peculiarities of the operation of the system. What factors can influence the current temperature regime of heat supply?

• Pollution of pipelines and radiators. To avoid this, periodic cleaning of the heating system should be carried out;
• Incorrect operation of the regulating and stop valves. Be sure to check the performance of all components;
• Violation of the boiler operation mode - sudden temperature jumps as a result - pressure.

Maintaining the optimal temperature regime of the system is possible only when right choice its components. For this, their operational and technical properties should be taken into account.

Battery heating can be adjusted using a thermostat, the principle of operation of which can be found in the video:

Each Management Company strive to achieve economical heating costs apartment building. In addition, residents of private houses are trying to come. This can be achieved if a temperature graph is drawn up, which will reflect the dependence of the heat produced by the carriers on the weather conditions on the street. Correct use of these data allow optimal distribution of hot water and heating to consumers.

What is a temperature chart

The same mode of operation should not be maintained in the coolant, because outside the apartment the temperature changes. It is she who needs to be guided and, depending on her, change the temperature of the water in heating objects. The dependence of the coolant temperature on the outside air temperature is compiled by technologists. To compile it, the values ​​\u200b\u200bof the coolant and the outside air temperature are taken into account.

During the design of any building, the size of the heating equipment supplied in it, the dimensions of the building itself and the cross-sections of the pipes must be taken into account. In a high-rise building, residents cannot independently increase or decrease the temperature, as it is supplied from the boiler room. Adjustment of the operating mode is always carried out taking into account the temperature graph of the coolant. The temperature scheme itself is also taken into account - if the return pipe supplies water with a temperature above 70 ° C, then the coolant flow will be excessive, but if it is much lower, there is a shortage.

Important! The temperature schedule is drawn up in such a way that at any air temperature in the street, a stable temperature is maintained in the apartments. optimal level heating at 22 °C. Thanks to him, even the most severe frosts become not terrible, because the heating systems will be ready for them. If it is -15 ° C outside, then it is enough to track the value of the indicator to find out what the water temperature in the heating system will be at that moment. The more severe the outdoor weather, the hotter the water inside the system should be.

But the level of heating maintained indoors depends not only on the coolant:

• Temperature outside;
• The presence and strength of the wind - its strong gusts significantly affect heat loss;
• Thermal insulation - high-quality processed structural parts of the building help to keep heat in the building. This is done not only during the construction of the house, but also separately at the request of the owners.

Heat carrier temperature table from outdoor temperature

In order to calculate the optimal temperature regime, it is necessary to take into account the characteristics that heating devices have - batteries and radiators. The most important thing is to calculate their specific power, it will be expressed in W / cm 2. This will most directly affect the transfer of heat from the heated water to the heated air in the room. It is important to take into account their surface power and the drag coefficient available for window openings and outer walls.

After all the values ​​\u200b\u200bare taken into account, you need to calculate the difference between the temperature in the two pipes - at the entrance to the house and at the exit from it. The higher the value in the inlet pipe, the higher in the return pipe. Accordingly, indoor heating will increase below these values.

Proper use of the coolant implies attempts by the inhabitants of the house to reduce the temperature difference between the inlet and outlet pipe. It could be construction work for wall insulation from the outside or thermal insulation of external heat supply pipes, insulation of ceilings above a cold garage or basement, insulation of the inside of the house or several works performed simultaneously.

Heating in the radiator must also comply with the standards. In the central heating systems usually varies from 70 C to 90 C depending on the air temperature outside. It is important to take into account that in corner rooms can not be less than 20 C, although in other rooms of the apartment it is allowed to drop to 18 C. If the temperature drops to -30 C outside, then the heating in the rooms should rise by 2 C. In other rooms, the temperature should also increase, provided that in rooms for various purposes it may be different. If there is a child in the room, then it can range from 18 C to 23 C. In pantries and corridors, heating can vary from 12 C to 18 C.

It is important to note! The average daily temperature is taken into account - if the temperature is about -15 C at night, and -5 C during the day, then it will be calculated by the value of -10 C. If at night it was about -5 C, and in the daytime it rose to +5 C, then heating is taken into account by the value of 0 C.

Schedule for supplying hot water to the apartment

In order to deliver the optimal DHW to the consumer, CHP plants must send it as hot as possible. Heating mains are always so long that their length can be measured in kilometers, and the length of apartments is measured in thousands of square meters. Whatever the thermal insulation of the pipes, heat is lost on the way to the user. Therefore, it is necessary to heat the water as much as possible.


However, water cannot be heated to more than its boiling point. Therefore, a solution was found - to increase the pressure.

It is important to know! As it rises, the boiling point of water shifts upwards. As a result, it reaches the consumer really hot. With an increase in pressure, risers, mixers and taps do not suffer, and all apartments up to the 16th floor can be provided with hot water without additional pumps. In a heating main, water usually contains 7-8 atmospheres, the upper limit usually has 150 with a margin.

It looks like this:

Hot water supply to winter time years must be continuous. Exceptions to this rule are accidents on heat supply. Hot water can only be turned off summer period for preventive work. Such work is carried out as in heating systems closed type as well as in open systems.