Increased temperature chart. The dependence of the coolant temperature on the outside air temperature

Reference temperature water in heating system depends on air temperature. That's why temperature chart coolant supply 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.

The calculations use normative indicator temperature. It is calculated according to special technique and included in the governing documents. This figure is based on the average temperature of the 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. By understanding the ultimate load, you can accurately calculate the characteristics necessary 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 coolant temperature graph, depending on outdoor 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 high pressure due to their deterioration. 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 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 system central heating.

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 hot coolant. 7 column - for the return.

The first three columns indicate fever- 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 in the 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, the heated coolant carries a potential hazard, 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. AT in public places and there are usually no special restrictions for them at various production facilities.

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.

When autumn confidently walks across the country, snow flies beyond the Arctic Circle, and in the Urals night temperatures stay below 8 degrees, then the word form “heating season” sounds appropriate. People recall past winters and try to figure out the normal temperature of the coolant in the heating system.

Prudent owners of individual buildings carefully revise the valves and nozzles of the boilers. Residents apartment building by October 1, they are waiting, like Santa Claus, a plumber from a management company. The ruler of valves and valves brings warmth, and with it - joy, fun and confidence in the future.

The Gigacalorie Path

Megacities sparkle with high-rise buildings. A cloud of renovation hangs over the capital. Outback prays on five-story buildings. Until demolished, the house has a calorie supply system.

The economy class apartment building is heated through a centralized heat supply system. The pipes are included in basement buildings. The supply of heat carrier is regulated by inlet valves, after which water enters the mud collectors, and from there it is distributed through risers, and from them it is supplied to batteries and radiators that heat housing.

The number of gate valves correlates with the number of risers. While doing repair work in a single apartment, it is possible to turn off one vertical, and not the whole house.

The spent liquid partially leaves through the return pipe, and partially is supplied to the hot water supply network.

degrees here and there

Water for the heating configuration is prepared at a CHP plant or in a boiler house. The water temperature standards in the heating system are prescribed in building regulations ax: the component must be heated to 130-150 °C.

The supply is calculated taking into account the parameters of the outside air. So, for the South Ural region, minus 32 degrees is taken into account.

To prevent the liquid from boiling, it must be supplied to the network under a pressure of 6-10 kgf. But this is a theory. In fact, most networks operate at 95-110 ° C, since the network pipes of most settlements are worn out and high pressure tear them up like a heating pad.

An extensible concept is the norm. The temperature in the apartment is never equal to the primary indicator of the heat carrier. Here it performs an energy-saving function elevator unit- jumper between the direct and return pipe. The norms for the temperature of the coolant in the heating system on the return in winter allow the preservation of heat at a level of 60 ° C.

The liquid from the straight pipe enters the elevator nozzle, mixes with return water and again goes into the house network for heating. The carrier temperature is lowered by mixing the return flow. What affects the calculation of the amount of heat consumed by residential and utility rooms.

hot gone

According to sanitary rules, the temperature of hot water at the points of analysis should lie in the range of 60-75 ° C.

In the network, the coolant is supplied from the pipe:

• in winter - from the reverse, so as not to scald users with boiling water;
• in summer - with a straight line, since in summer the carrier is heated no higher than 75 ° C.

A temperature chart is drawn up. The average daily return water temperature should not exceed the schedule by more than 5% at night and 3% during the day.

Parameters of distributing elements

One of the details of warming a home is a riser through which the coolant enters the battery or radiator from the temperature norms of the coolant in the heating system require heating in the riser in winter time in the range of 70-90 °C. In fact, the degrees depend on the output parameters of the CHP or boiler house. In the summer when hot water needed only for washing and showering, the range moves to the range of 40-60 ° C.

Observant people may notice that in a neighboring apartment, the heating elements are hotter or colder than in his own.

The reason for the temperature difference in the heating riser is the way the hot water is distributed.

In a single-pipe design, the heat carrier can be distributed:

• above; then the temperature is upper floors higher than on the bottom;
• from below, then the picture changes to the opposite - it is hotter from below.

In a two-pipe system, the degree is the same throughout, theoretically 90 ° C in the forward direction and 70 ° C in the opposite direction.

Warm like a battery

Suppose that the structures of the central network are reliably insulated along the entire route, the wind does not walk through the attics, stairwells and basements, the doors and windows in the apartments are insulated by conscientious owners.

We assume that the coolant in the riser complies with the building regulations. It remains to find out what is the norm for the temperature of the heating batteries in the apartment. The indicator takes into account:

• outdoor air parameters and time of day;
• the location of the apartment in terms of the house;
• residential or utility room in the apartment.

Therefore, attention: it is important, not what is the degree of the heater, but what is the degree of air in the room.

During the day in the corner rooms, the thermometer should show at least 20 ° C, and in the centrally located rooms 18 ° C is allowed.

At night, air in the dwelling is allowed to be 17 ° C and 15 ° C, respectively.

Theory of linguistics

The name "battery" is household, denoting a number of identical items. In relation to the heating of housing, this is a series of heating sections.

The temperature standards of heating batteries allow heating no higher than 90 ° C. According to the rules, parts heated above 75 ° C are protected. This does not mean that they need to be sheathed with plywood or bricked. Usually they put a lattice fence that does not interfere with air circulation.

Cast iron, aluminum and bimetallic devices are common.

Consumer choice: cast iron or aluminum

Aesthetics cast iron radiators- a parable in the language. They require periodic painting, as regulations require that the work surface be smooth and allow dust and dirt to be easily removed.

A dirty coating forms on the rough inner surface of the sections, which reduces the heat transfer of the device. But the technical parameters cast iron products on high:

• little susceptible to water corrosion, can be used for more than 45 years;
• they have a high thermal power per 1 section, therefore they are compact;
• they are inert in heat transfer, therefore they smooth out temperature fluctuations in the room well.

Another type of radiators is made of aluminum. Lightweight construction, painted in the factory, does not require painting, easy to clean.

But there is a drawback that overshadows the advantages - corrosion in aquatic environment. Certainly, inner surface heaters are insulated with plastic to avoid contact of aluminum with water. But the film may be damaged, then it will begin chemical reaction with the release of hydrogen, when creating overpressure gas aluminum appliance may burst.

The temperature standards of heating radiators are subject to the same rules as batteries: it is not so much heating that matters metal object how much air heating in the room.

In order for the air to warm up well, there must be sufficient heat removal from working surface heating structure. Therefore, it is strongly not recommended to increase the aesthetics of the room with shields in front of the heating device.

Stairwell heating

Since we are talking about apartment building, then it should be mentioned stairwells. The norms for the temperature of the coolant in the heating system state: the degree measure on the sites should not fall below 12 ° C.

Of course, the discipline of the tenants requires that the doors be closed tightly. entrance group, do not leave the transoms of stair windows open, keep the glass intact and promptly report any problems to the management company. If the Criminal Code does not take timely measures to insulate the points of probable heat loss and maintain the temperature regime in the house, an application for recalculation of the cost of services will help.

Changes in heating design

Replacement of existing heating devices in the apartment is carried out with the obligatory coordination with management company. Unauthorized change in the elements of warming radiation can disrupt the thermal and hydraulic balance of the structure.

The heating season will begin, a change in the temperature regime in other apartments and sites will be recorded. Technical inspection premises will reveal unauthorized changes in the types of heating devices, their number and size. The chain is inevitable: conflict - trial - fine.

So the situation is resolved like this:

• if not old ones are replaced with new radiators of the same size, then this is done without additional approvals; the only thing to apply to the Criminal Code is to turn off the riser for the duration of the repair;
• if new products differ significantly from those installed during construction, then it is useful to interact with the management company.

Heat meters

Let us recall once again that the heat supply network of an apartment building is equipped with heat energy metering units, which record both the consumed gigacalories and the cubic capacity of water passed through the house line.

In order not to be surprised by bills containing unrealistic amounts for heat at temperatures in the apartment below the norm, before the start of the heating season, check with the management company whether the meter is in working order, whether the verification schedule has been violated.

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 the batteries is carried out according to the following formula: Psp \u003d P / Fact Where P is the maximum power, W, Fact is the radiator area, cm². The dependence of heat output on the temperature in the street According to the data obtained, it is compiled temperature regime for heating and a heat transfer schedule 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.

Temperature chart of the heating system

Regulator benefits:

1. The temperature regime is strictly maintained.
2. Exclusion of liquid overheating.
3. Economy of fuel and energy.
4. The consumer, regardless of distance, receives heat equally.

Table with temperature graph Boiler operation mode depends on the weather environment. If we take various objects, for example, a factory building, a multi-storey building and private house, all will have an individual heat chart.

Energy Blog

Attention

Looking through the statistics of visiting our blog, I noticed that search phrases such as, for example, “what should be the temperature of the coolant at minus 5 outside?” appear very often. I decided to lay out the old schedule for the quality regulation of heat supply based on the average daily outdoor temperature.

Important

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 the article on regulating the temperature of the coolant). Work on this schedule heating network in Ufa (Bashkiria).

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

temperature graph

The temperature of the heat carrier at the inlet to the heating system at quality regulation the heat supply depends on the outdoor temperature, that is, the lower the outdoor temperature, the higher the temperature should be when the coolant enters the heating system. The temperature graph is selected when designing the heating system of the building, the size of the heating devices, the flow rate of the coolant in the system, and, consequently, the diameter of the distributing pipelines depend on it.
To indicate the temperature graph, two numbers are used, for example, 90-70 ° C - this means that at the estimated outdoor temperature (for Kyiv -22 ° C), to create comfortable temperature indoor air (for housing 20°C), the heating medium (water) must enter the heating system with a temperature of 90°C, and leave it with a temperature of 70°C.

Temperature chart of the heating system 95 70 snip table

Info

Analysis and adjustment of operating modes is carried out using a temperature scheme. For example, the return of a liquid with an elevated temperature will indicate high coolant costs.

Underestimated data will be considered as a consumption deficit. Previously, for 10-storey buildings, a scheme with calculated data of 95-70°C was introduced.

The buildings above had their chart 105-70°C. Modern new buildings may have a different scheme, at the discretion of the designer. More often, there are diagrams of 90-70°C, and maybe 80-60°C. Temperature graph 95-70: Temperature graph 95-70 How is it calculated? The control method is selected, then the calculation is made. The calculation-winter and reverse order of water inflow, the amount of outside air, the order at the break point of the diagram are taken into account. There are two diagrams, where one of them considers only heating, the other one considers heating with hot water consumption.

Heating temperature chart

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 centralized system drawing up the correct temperature schedule for the heating boiler room is required to ensure the optimal comfortable temperature in the 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 Temperature controller It is often not necessary to make similar calculations for autonomous heating systems of a private house.

Temperature schedule for the operation of sources and heating networks

Dependency graph may vary. A particular chart has a dependency on:

1. Technical and economic indicators.
2. Equipment for a CHP or boiler room.
3. climate.

High performance of the coolant provides the consumer with a large thermal energy. An example of a circuit is shown below, where T1 is the temperature of the heat carrier, Tnv is the outdoor air: The diagram of the returned heat carrier is also used.

A boiler house or CHP according to such a scheme can evaluate the efficiency of the source. It is considered high when the returned liquid arrives cooled. The stability of the scheme depends on the design values ​​of the liquid flow of high-rise buildings. If the flow rate through the heating circuit increases, the water will return uncooled, as the flow rate will increase. And vice versa, when minimum flow, return water will be cool enough.

The supplier's interest is, of course, in the flow of return water in a chilled state. But there are certain limits to reduce the flow, since a decrease leads to losses in the amount of heat.

The consumer will begin to lower the internal degree in the apartment, which will lead to a violation building codes and the discomfort of the inhabitants. What does it depend on? The temperature curve depends on two quantities: outside air and heating medium. Frosty weather leads to an increase in the degree of coolant. When designing a central source, the size of the equipment, the building and the section of pipes are taken into account. The value of the temperature leaving the boiler room is 90 degrees, so that at minus 23°C, it would be warm in the apartments and have a value of 22°C. Then the return water returns to 70 degrees. These standards are in line with the normal comfortable living in home.

Temperature chart of the heating system - calculation procedure and ready-made tables

For networks operating according to temperature schedules of 95-70°С and 105-70°С (columns 5 and 6 of the table), the water temperature in the return pipeline of heating systems is determined by column 7 of the table. For consumers connected via independent scheme connection, the water temperature in the direct pipeline is determined by column 4 of the table, and in the return pipeline by column 8 of the table.

The temperature schedule for regulating the heat load is developed from the conditions of the daily supply of heat energy for heating, which ensures the need for buildings in heat energy, depending on the outside temperature, in order to ensure that the temperature in the premises is constant at a level of at least 18 degrees, as well as covering the heat load of hot water supply with ensuring DHW temperature in places of water intake not lower than + 60 ° С, in accordance with the requirements of SanPin 2.1.4.2496-09 “Drinking water.

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 during the supply of hot water to houses with average daily temperature outside air.
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;
• the degree of heat transfer of heating devices;
• 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 maximum power device in W and 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, the temperature regime of heating is selected 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 performed measures 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.

The temperature chart of the heating system 95 -70 degrees Celsius is the most demanded temperature chart. By and large, we can say with confidence that all central heating systems operate in this mode. The only exceptions are buildings with autonomous heating.

But also in autonomous systems there may be exceptions when using condensing boilers.

When using boilers operating on the condensation principle, the temperature curves of heating tend to be lower.

Application of condensing boilers

For example, when maximum load for a condensing boiler, there will be a mode of 35-15 degrees. This is due to the fact that the boiler extracts heat from the exhaust gases. In a word, with other parameters, for example, the same 90-70, it will not be able to work effectively.

Distinctive properties of condensing boilers are:

• high efficiency;
• profitability;
• optimal efficiency at minimum load;
• quality of materials;
• high price.

You have heard many times that the efficiency of a condensing boiler is about 108%. Indeed, the manual says the same thing.

But how can this be, because we are still with school desk taught that more than 100% does not happen.

1. The thing is that when calculating the efficiency of conventional boilers, exactly 100% is taken as a maximum.
   But ordinary ones simply throw flue gases into the atmosphere, and condensing ones utilize part of the outgoing heat. The latter will go to heating in the future.
2. The heat that will be utilized and used in the second round and added to the efficiency of the boiler. Typically, a condensing boiler utilizes up to 15% of flue gases, this figure is adjusted to the efficiency of the boiler (approximately 93%). The result is a number of 108%.
3. Undoubtedly, heat recovery is a necessary thing, but the boiler itself costs a lot of money for such work..
   The high price of the boiler due to stainless heat exchange equipment, which utilizes heat in the last path of the chimney.
4. If instead of such stainless equipment we put ordinary iron equipment, then it will become unusable after a very short span time . Since the moisture contained in the flue gases has aggressive properties.
5. The main feature of condensing boilers is that they achieve maximum efficiency with minimum loads.
   Conventional boilers (), on the contrary, reach the peak of economy at maximum load.
6. The beauty of it useful property that during all heating period, the heating load is not always at its maximum.
   On the strength of 5-6 days, an ordinary boiler works at maximum. Therefore, a conventional boiler cannot match the performance of a condensing boiler, which has maximum performance with minimal loads.

You can see a photo of such a boiler a little higher, and a video with its operation can be easily found on the Internet.

conventional heating system

It is safe to say that the heating temperature schedule of 95 - 70 is the most in demand.

This is explained by the fact that all houses that receive heat from central heat sources are designed to work in this mode. And we have more than 90% of such houses.

The principle of operation of such heat production occurs in several stages:

• heat source (district boiler house), produces water heating;
• heated water, through the main and distribution networks moves towards consumers;
• in the house of consumers, most often in the basement, through the elevator unit, hot water is mixed with water from the heating system, the so-called return flow, the temperature of which is not more than 70 degrees, and then heated to a temperature of 95 degrees;
• further heated water (the one that is 95 degrees) passes through the heaters of the heating system, heats the premises and again returns to the elevator.

Advice. If you have a cooperative house or a society of co-owners of houses, then you can set up the elevator with your own hands, but this requires you to strictly follow the instructions and correctly calculate the throttle washer.

Poor heating system

Very often we hear that people's heating does not work well and their rooms are cold.

There can be many reasons for this, the most common are:

• schedule temperature system heating is not observed, the elevator may be incorrectly calculated;
• the house heating system is heavily polluted, which greatly impairs the passage of water through the risers;
• fuzzy heating radiators;
• unauthorized change of the heating system;
• poor thermal insulation of walls and windows.

A common mistake is an incorrectly dimensioned elevator nozzle. As a result, the function of mixing water and the operation of the entire elevator as a whole is disrupted.

This could happen for several reasons:

• negligence and lack of training of operating personnel;
• incorrectly performed calculations in the technical department.

During the many years of operation of heating systems, people rarely think about the need to clean their heating systems. By and large, this applies to buildings that were built during the Soviet Union.

All heating systems must be hydropneumatic flushing in front of everyone heating season. But this is observed only on paper, since ZhEKs and other organizations carry out these works only on paper.

As a result, the walls of the risers become clogged, and the latter become smaller in diameter, which violates the hydraulics of the entire heating system as a whole. The amount of transmitted heat decreases, that is, someone simply does not have enough of it.

You can do hydropneumatic purge with your own hands, it is enough to have a compressor and a desire.

The same applies to cleaning radiators. Over many years of operation, radiators inside accumulate a lot of dirt, silt and other defects. Periodically, at least once every three years, they need to be disconnected and washed.

Dirty radiators greatly impair the heat output in your room.

The most common moment is an unauthorized change and redevelopment of heating systems. When replacing old metal pipes with metal-plastic ones, diameters are not observed. And sometimes various bends are added, which increases local resistance and worsens the quality of heating.

Very often, with such unauthorized reconstruction, the number of radiator sections also changes. And really, why not give yourself more sections? But in the end, your housemate living after you will receive less of the heat he needs for heating. And the last neighbor, who will receive less heat the most, will suffer the most.

An important role is played thermal resistance building envelopes, windows and doors. As statistics show, up to 60% of heat can escape through them.

Elevator node

As we said above, all water-jet elevators are designed to mix water from the supply line of heating networks into the return line of the heating system. Thanks to this process, system circulation and pressure are created.

As for the material used for their manufacture, both cast iron and steel are used.

Consider the principle of operation of the elevator in the photo below.

Through pipe 1, water from heating networks passes through the ejector nozzle and with high speed enters the mixing chamber 3. There, water is mixed with it from the return of the heating system of the building, the latter is supplied through pipe 5.

The resulting water is sent to the heating system supply through diffuser 4.

In order for the elevator to function correctly, it is necessary that its neck be correctly selected. To do this, calculations are made using the formula below:

Where ΔРnas is the design circulation pressure in the heating system, Pa;

Gcm - water consumption in the heating system kg / h.

Note!
True, for such a calculation, you need a building heating scheme.