Water temperature standards for heating apartments and houses, scheduling for heat supply

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

What determines the temperature of the water in heating

For the heat supply to work properly, a graph of the water temperature in the heating system is required. According to it, the optimal degree of heating of the coolant is determined, depending on the influence of certain external factors. It can be used to determine what temperature of the water in the heating batteries should be in a certain period of time the system is operating.

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

Often, the low temperature of the heating batteries is not a violation of the norms for heating the room. A low-temperature heating system was simply designed. That is why the exact calculation of water heating should be given special attention.

The optimum water temperature in the heating pipes depends largely on external factors. To determine it, the following parameters must be taken into account:

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

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

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

Heating standards in apartments and houses

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

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

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

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

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

The management company is responsible for compliance with these standards. In case of violation, you can request a recalculation of payment for heating services. For autonomous heating, a table of temperatures for heating is made, where the values ​​for heating the coolant and the degree of load on the system are entered. At the same time, no one bears responsibility for violation of this schedule. This will affect the comfort of staying in a private home.

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

Calculation of the temperature mode of heating

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

The first step is to determine the heat loss in the building. Based on the data received, a boiler with the appropriate power is selected. Then comes the most difficult design stage - determining the parameters of heat supply batteries.

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

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

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

• Maximum permissible water temperature in the heating system - t1... It depends on the power of the boiler, the temperature limit of exposure to pipes (especially polymeric ones);
• Optimal the temperature that should be in the return pipes of the heating - t This is determined by the type of distribution of the mains (one-pipe or two-pipe) and the total length of the system;
• The required degree of heating the air in the room - t.

With this data, you can calculate the temperature head of the battery using the following formula:

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

Further, to determine the power of the radiator, you should use the following formula:

Q = k * F * Tnap

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

By varying various indicators of the maximum and minimum water temperature in the heating system, it is possible to determine the optimal operating mode of the system. It is important to correctly calculate the required power of the heater from the beginning. Most often, the indicator of low temperature in heating batteries is associated with heating design errors. Experts recommend adding a small margin to the resulting value of the radiator power - about 5%. This will be needed in case of a critical drop in temperature outside in winter.

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

Water temperature in the boiler and heating pipes

After performing the above calculation, it is necessary to adapt the heating temperature table for the boiler and pipes. During the operation of the heat supply, there should be no emergency situations, a frequent cause of which is a violation of the temperature schedule.

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

The situation with autonomous heat supply is much more complicated. In this case, control completely depends on the owner of the house. It is important to ensure that the temperature of the water in the heating pipes does not rise beyond the schedule. This may affect the safety of the system.

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

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

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

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

Influence of temperature on the properties of the coolant

In addition to the factors described above, the temperature of the water in the heat supply pipes affects its properties. The principle of operation of gravitational heating systems is based on this. With an increase in the heating level of water, it expands and circulation occurs.

However, in the case of using antifreeze, exceeding the normal temperature in the radiators can lead to different results. Therefore, for heat supply with a heat carrier other than water, you should first find out the permissible indicators for its heating. This does not apply to the temperature of district heating radiators in an apartment, since antifreeze-based liquids are not used in such systems.

Antifreeze is used if there is a likelihood of the effect of low temperature on the radiators. Unlike water, it does not begin to change from a liquid to a crystal-like state when it reaches 0 ° C. However, if the work of the heat supply is beyond the norms of the temperature table for heating in a larger direction, the following phenomena may occur:

• Foaming... This entails an increase in the volume of the coolant and, as a consequence, an increase in pressure. The reverse process will not be observed when the antifreeze cools down;
• Limescale formation... Antifreeze contains a certain amount of mineral components.If the heating temperature in the apartment is violated in a large direction, they begin to precipitate. Over time, this will lead to clogging of pipes and radiators;
• Increase in density. Malfunctions in the operation of the circulation pump may occur if its rated power has not been designed for the occurrence of such situations.

Therefore, it is much easier to monitor the temperature of the water in the heating system of a private house than to control the degree of heating of the antifreeze. In addition, compositions based on ethylene glycol, when evaporated, emit a gas harmful to humans. Currently, they are practically not used as a heat carrier in autonomous heat supply systems.

Before pouring antifreeze into the heating, all rubber gaskets should be replaced with paranite ones. This is due to the increased permeability of this type of coolant.

Methods for normalizing the temperature regime of heating

The minimum value of the water temperature in the heating system is not the main threat to its operation. This, of course, affects the microclimate in living quarters, but in no way affects the functioning of the heat supply. If the water heating rate is exceeded, emergency situations may arise.

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

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

To avoid their appearance, it is recommended to upgrade the heating as follows:

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

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

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