Refinement of the heating system. Modernization of the heating system in the house and apartment. Individual room temperature control

During the modernization of the hot water heating system, the wood burning stove was replaced with a natural gas stove. Specific heat combustion of firewood 10 7 J / kg, natural gas- 3.2 10 7 J / kg. How is it necessary to change (increase or decrease) the mass of fuel burned in the furnace per unit time in order to maintain the same rate of water circulation in the heating system? Explain the answer.

Water heating

The need for heating arose in ancient times, at the same time as people learned to build the most primitive dwellings for themselves. The first dwellings were heated by bonfires, then they were replaced by hearths, then by stoves. In the course of technological progress, heating systems have been constantly improved and improved. People learned to use new types of fuel, invented different designs heating appliances, sought to reduce fuel consumption and do the job heating system autonomous, not requiring constant human control. Currently, the most widely used systems of water heating, which is used for heating as apartment buildings in cities and small buildings in countryside. The principle of operation of a water heating system (see figure) is conveniently explained using the heating system of a small residential building as an example.

The source of heat for the heating system is furnace 1, in which different kinds organic fuel - firewood, peat, coal, natural gas, oil products, etc. The furnace heats the water in the boiler 2. When heated, the water expands and its density decreases, as a result of which it rises from the boiler up the vertical main riser 3. At the top of the main riser there is an exit to the atmosphere expansion tank 4, which is necessary due to the fact that the volume of water increases when heated. Pipe 5 departs from the upper part of the main riser (“hot pipeline”), through which water is supplied to heating devices - batteries 6, each consisting of several sections. After flowing through the batteries, the cooled water through the return pipeline 7 again enters the boiler, heats up again and rises again through the main riser. With the simplest single pipe scheme all batteries are connected to each other in such a way that all sections are connected in parallel to the hot and return pipelines. Since the water gradually cools as it flows through the batteries, in order to maintain the same temperature in different rooms they make batteries with different number sections (that is, with different surface areas). In those rooms in which water enters earlier and therefore has more high temperature, the number of sections in the batteries is made smaller, and vice versa. The water in such a heating system circulates automatically as long as the fuel is burning in the furnace. In order for circulation to be possible, all hot pipelines and return pipelines in the system are made either vertical or with a slight slope in the right direction - so that water flows through them from the main riser back to the boiler under the action of gravity (“gravity”). The rate of water circulation and the degree of heating can be adjusted by reducing or increasing the amount of fuel burned in the furnace per unit time. Water circulates in heating systems of this type the better, the greater the distance in height between the boiler and the hot pipeline. Therefore, they try to place the furnace with the boiler as low as possible - usually they are placed in the basement or, in its absence, lowered to ground level, and the hot pipeline is carried through the attic.

For normal operation of the heating system, it is very important that there is no air inside it. For release air locks, which can occur in pipes and batteries, are special air vents that open when the system is filled with water (not shown in the figure). Also, taps 8 are installed on the pipes in the lower part of the system, with the help of which water is drained from the heating system, if necessary.

Solution.

Answer: reduce.

Explanation: the rate of water circulation in the heating system, other things being equal, is determined by the rate of water heating in the boiler. When burning natural gas, more heat is released than when the same mass of firewood is burned, and the water in the boiler heats up faster. Therefore, in order to maintain the same rate of water circulation in the system, it is necessary to reduce the mass of fuel burned in the furnace.

The cost of tariffs for heat and hot water supply is "unaffordable" for most of our compatriots. And it's not just the desire of public utilities to get as much profit as possible. The reasons for this phenomenon are banal: the rise in the cost of hydrocarbons and the housing stock, most of which was built in the middle of the last century, when energy efficiency was not paid much attention to during construction. This publication will review measures to modernize the heating systems of residential buildings, which are already long time used in several European countries.

What does thermal modernization of a building mean?

Experts define this concept, as a set of measures to bring apartment building in accordance with modern energy efficiency standards. This includes measures related to reducing the heat loss of a building through walls, ceilings, roofs, basements, etc. Large heat losses occur due to low thermal performance and poor tightness of old windows and doors. In addition, thermal modernization affects the issues of re-equipment of engineering systems (ventilation, heating, hot water supply), the transition to combined (geothermal solar) heat supply sources.

Important! Insulation of external fences, without re-equipment of heating and ventilation systems at home, is not effective and does not give a positive result (which often happens), and most often leads to an increase in energy costs by the consumer of utility resources.

A set of measures aimed at reducing heat consumption and improving the energy efficiency of buildings will be considered.

Insulation of enclosing structures

This activity can be divided into several important species works.

Insulation of external walls from the outside of the house.

Thermal insulation of enclosing structures is the application of an additional layer of material with a low coefficient of thermal conductivity to the walls. These measures make it possible to eliminate "cold bridges", increase the thermal insulation properties of walls, and effectively solve the problem of "material porosity". The following wall insulation technologies can be applied: seamless insulation system; creation of an insulating wall; arrangement of a ventilated facade.

Insulation of the roof, attic floors.

If the attic of the house is not heated, then work is carried out to insulate the floor under the attic with the protection of the insulating layer from mechanical damage.

Thermal insulation of floors above the basement.

This type of work is carried out from the side of the basement by gluing thermal insulation boards to the cover.

Advice! If it is impossible to carry out measures for the thermal insulation of walls from the outside (an architectural monument, a complex relief of the facade, etc.), then it is necessary to insulate the outer walls from the inside of the building by laying polystyrene foam boards under plaster or drywall.

Reducing heat loss through windows

According to experts, up to 30% of the heat from heated rooms “leaves” through the windows. A radical way to solve this problem is to replace the old wooden windows for energy saving. It is enough to reduce their size, especially if the question concerns windows on stairwells. In most layouts of apartment buildings, there is an excess area for stair lighting. window openings, which causes large heat losses.

Modernization of the ventilation system

As you know, the most common way to organize air circulation in the premises of apartment buildings is natural ventilation. Air is removed through exhaust ducts located in kitchens and bathrooms. tributary fresh air from the street is organized through natural leaks in windows and doors.

When replacing old windows with energy-efficient and airtight ones, the problem of heat loss is solved, but a new one appears: a sharp decrease in supply air. This problem is solved by modernizing the ventilation system, namely, by arranging ventilation with controlled air flow. In practice, this is solved by setting supply valves, windows with built-in hygro-dependent fans or installations of forced supply of fresh air to the premises.

Reconstruction of the heating system

Specialists pay special attention to high heat consumption, which occurs due to the low efficiency of morally and technically obsolete home heating systems, which were not originally designed with excessive heat consumption. The main problems of old heating systems (CO) can be formulated as follows:

Poor or incorrect hydraulic balancing. This problem is often associated with unauthorized intervention of residents in the design of the heating system (installation of additional sections on radiators, replacement of batteries, pipelines, etc.)

Poor thermal insulation of heat supply pipes or its complete absence.

Structurally obsolete heat and distribution points.

Re-equipment of thermal units

Modernization of these facilities is a rather complicated and expensive process. Which includes the following changes:

Replacement of the elevator unit of the heating system with an automated one. In the case of connecting the house to the heat main according to an independent scheme, an automated individual heat point is installed; when using a dependent one, a scheme with pumping admixture is used. Depending on the scheme used, all equipment must be weather-dependent and automatically stabilize the pressure in CO by regulating the supply of coolant.

Important! Replacing an outdated elevator assembly with an economizer will not allow the use of thermostats for heating radiators and balancing valves. The elevator simply "will not pull" additional hydraulic resistance, which will inevitably increase when using these devices.

Replacement of old heat exchangers with energy efficient ones.

Elimination of leaks in CO and replacement of valves.

Heating system balancing

Fortunately, the effectiveness of this event is no longer in doubt. The installation of balancing valves for a heating system on return risers with a limitation of the coolant temperature is a prerequisite for a competent modernization of CO, especially in houses with a large percentage of autonomous heating by gas boilers.

Installation of individual control devices

The installation of thermostats with an air temperature sensor on each battery, in addition to additional comfort for the residents of this building, will significantly reduce the consumption of thermal energy. The air temperature increased through the window openings (the sun warmed up), the thermostat reduced the amount of coolant for a specific heater.

Among the mandatory measures for the reconstruction of the heating system, carried out as part of the thermal modernization of the whole house, one can single out the installation of a common house heat supply metering unit and the transition to apartment heat metering. It is these measures that most stimulate residents to save.

Thermal modernization of an apartment building requires large financial costs. But in order to achieve significant savings by the end consumer (which means a return of money and profit for energy service investors), it is necessary to carry out comprehensive measures to reduce the amount of consumed thermal energy or thermal modernization.

Ecology of consumption. Science and technology: When implementing energy-saving measures, half-hearted measures, despite a one-time reduction in capital costs, pay off long and hard, and complex measures allow you to return money and make a profit much faster

Modernization of heating systems in multi-apartment residential buildings and social infrastructure facilities is one of the most pressing topics for professionals in the utility industry today. Main question of the day sounds like this: “What are the necessary and sufficient conditions for obtaining an economic result that is adequate to the expectations of consumers of utility resources and potential investors of energy services?” Practice proves that half-way measures, despite a one-time reduction in capital costs, pay off for a long time and hard, and complex measures allow you to return money and make a profit much faster.

So, let's consider sequentially a set of measures being implemented today at housing and communal services facilities aimed at reducing the heat consumption of communal facilities (including MKD) and their effectiveness.

*Energy efficient measures and their essence*			*Average savings*
1	*Installation of a heat metering unit*	Without taking into account, talking about savings and payback is meaningless.	*
2	*Elimination of heat losses*	Insulation of enclosing structures, entrances and basements, thermal insulation of communications.	**
3	*Modernization of the thermal unit*	Replacement of elevator nodes with AITP or AUU, depending on the scheme for connecting the object to the heating network. Setting up the AITP controller for reduced schedule heating at night, weekends and holidays (especially relevant for administrative buildings, educational institutions).	*15-25%*
4	*Balancing the system by risers*	Installation of automatic balancing valves in order to equalize the flow rate of the coolant along the risers at different distances from the heat input.	*5-10%*
5		Installation on all heating appliances automatic radiator thermostats, or replacement of heating devices with new ones with built-in thermostats.	*10-15%*
6		For buildings with horizontal apartment-by-apartment wiring of the heating system - installation of a heat meter at the entrance to the apartment. For houses with vertical wiring - the introduction of alternative accounting systems, for example,INDIV AMR.	*10-15%*
TOTAL:			*30-50%*

Now let's evaluate the most common mistakes that are made on the ground during the planning and implementation of heat saving measures.

1. Installation of a heat metering unit

Fortunately, no one doubts the need for this step today, and the law does not provide any other alternative. Therefore, this stage is always implemented.

However, there are still unjustified expectations of savings as a result of a simple installation of a heat meter. Hypothetically, these expectations may be justified: sometimes it turns out that the building consumes less heat than the norm, and then after the installation of a heat meter, the amount of payments for heating is reduced. But this is a lottery, making a rule out of it is a big mistake. You need to understand well: the counter is just a measuring tool, which in itself does not save anything.

2. Elimination of heat losses

It is produced as needed, which, in theory, should be determined during an energy audit. Unfortunately, surveys are not always carried out, as a result, at some facilities, either the necessary overhaul is not carried out at all, or thermal gaps remain that can sometimes negate the effect of subsequent measures. The price of such a mistake is high: in about 10-15% of cases, instead of saving, a direct loss is obtained. This is not surprising, because if you install automation in a house with holes in the walls, which will unsuccessfully try to heat it, and a heat meter, then the readings of the latter, of course, will go off scale. And to name the supposedly low efficiency of energy-saving measures as the reason for this result is fundamentally wrong.

Another common mistake is expecting savings from building insulation without modernizing the heating system. If you have an elevator in your basement, then the heat consumption will always be the same, regardless of whether the walls keep warm or freeze through, because. this consumption depends only on the mixing ratio of the elevator, which is a constant value. Yes, the building will be warm, often (and usually) too warm, because. there will be no opportunity to reduce costs. Its inhabitants will have only one way out: open the windows and let the excess heat out, still paying for it in full. It is those surpluses that automation allows you to cut off at the inlet, up to the heat meter.

In 2011, a large-scale experiment was completed: full-scale tests of various energy-efficient solutions, which were carried out for several years by Danfoss, the Government of Moscow and MNIITEP on the basis of three real residential buildings No. 51, 53 and 59 on Obruchev Street in Moscow. Since 2008 in all three buildings under the city program overhaul reconstruction was carried out, including the installation of hinged ventilated facades and installation plastic windows. Thus, all of them fully complied with modern standards for thermal insulation. At the same time, no work was carried out to modernize the heating system in house No. 51. As a result, heat consumption at this facility has not decreased. Moreover, in the winter of 2010-2011. it turned out to be 1.9% higher than in 2008-2009. At the same time, in building No. 59, where a comprehensive reconstruction of the heating system was carried out, heat consumption decreased by 44.6%.

3. Modernization of the thermal unit

From the above, a simple conclusion follows: elevator schemes and energy saving are incompatible things. Therefore, if you want to save money, as well as provide the inhabitants of the building with the opportunity to maintain a comfortable microclimate in the premises, then the elevator thermal unit must be changed to an automated one. If the object is connected to the heating network according to an independent scheme, this is an automated individual heating point (AITP) with a heat exchanger. If the connection is dependent, then the automated control unit (ACU), i.e. pumping scheme. In principle, the same heat point, but without a heat exchanger. Both schemes provide for weather-dependent regulation of the coolant supply to the system, as well as automatic maintenance temperature graph, i.e. regulation depending on the internal heat consumption. Both schemes provide forced circulation of the coolant in the system.

AT last years many utilities are trying to promote the idea of using the so-called. economizers - adjustable electronic hydraulic elevators. Their device is a little more complicated than that of conventional ones: an electronic unit connected to an outdoor temperature sensor controls a simple electromagnetic drive, which pushes the needle into the nozzle of the jet pump, thereby reducing the pressure of hot network water. You need to be aware that an adjustable elevator has all the same disadvantages as an unregulated one, because in fact it is practically the same device. That's why:

You will not be able to use radiator thermostats in the system and balancing valves, because any elevator is a low-power device and additional hydraulic resistance is beyond its power;
For normal operation of the hydraulic elevator, the pressure in front of it must be at least 15 m of water column (see "Rules technical operation thermal power plants”), while in reality, in the conditions of Russian heating networks, such indicators are not always provided and not in all sections of the network, and sometimes they are three to four times less than the required value;
If for some reason the heating network does not withstand the temperature schedule, then either an overheating or an underheating occurs at the facility, because. the flow in the system is constant, and the hydraulic elevator is a passive device. If, due to the “overgrowth” of old pipes with deposits, the hydraulic resistance of the system increases, then it becomes cold in the house;
Network water must not only deliver heat to homes, but also heat water for hot water supply (DHW), so its temperature never drops below 70 ° C. Those. from a certain moment, no matter what the outside temperature is, heating batteries continue to be hot. The consequences are well known: stuffiness, open windows, "extra" heat is used to heat the street, but you still have to pay money for it. What a savings!

There is another "fly in the ointment". Even an eighth grader understands that with a decrease in the nozzle area adjustable elevator due to the introduction of a needle into it, the jet at the exit from this nozzle becomes less powerful, and therefore the suction force of water from the return pipe of the heating system also decreases. Those. the more the needle moves into the nozzle, the lower the coolant flow in the system becomes, in other words, the water circulation in the heating circuit slows down. And at some point, this expense begins to be enough only to “pump” the riser closest to the elevator, while the rest hot water does not arrive, and they begin to cool rapidly.

4. System balancing

For some reason, often the modernization of the heating system is completed at the stage of replacing the heating unit. Meanwhile, this is clearly not enough. The hydraulic resistance of the system increases with distance from the thermal input, as a result, overheating occurs in one risers, and underheating occurs in others at the same time. In MKD, this is usually corner apartments, the last ones in the chain. If you regulate them, then in the intermediate ones there will be overheating and constantly open windows. That is, we get what we wanted to get rid of. Therefore, the installation of automatic balancing valves on risers is a prerequisite for a complete modernization of the heating system.

It should be noted that in recent years this solution has been further improved. Danfoss specialists have developed QT thermocouples, thanks to which AB-QM automatic balancing valves begin to regulate the flow of the heating medium through the risers, depending on the change in the temperature of the return heating medium. This technology has made it possible to single pipe systems heating to two-pipe in terms of energy efficiency.

In 2009, during an experiment on Obruchev Street in Moscow, in houses No. 53 and 59, elevator thermal nodes replaced by automated control units (AUU)Danfoss with weather control (implemented using universal controllersECLComfort) and installed automatic radiator thermostats on all heating appliances in the apartments. At the same time, the balancing of the heating system was carried out only in house No. 59: here, an automatic balancing valve was installed on each of the 25 risersAB-QM. In 2010, the balancing of the system in house No. 59 was brought to its logical conclusion by equipping the valvesAB-QM thermocouplesQt.

As a result, house No. 53 (without balancing) recorded a decrease in heat consumption by 33.8%, while house No. 59 (with balancing) - by 44.6%, as mentioned above. That is, even in a single-entrance building, balancing gives a quite tangible economic effect. Moreover, in the winter of 2010-2011, after the installation of thermostatic elementsQT, consumption has decreased in relation to the level of 2009-2010. by almost 12% (or 7.5% compared to the level of 2008-2009), which proves the justification for using this technology.

5. Equipment of heating devices with means of individual regulation

Very often we hear that this measure is not mandatory and creates only additional comfort for the inhabitants of the building, without providing any savings. First, even in this case, it would be worth implementing it, because It is precisely in ensuring the maximum level of comfort in residential and other buildings that the main task of public utilities lies. If, of course, we move a little away from the Soviet model of work. Secondly, it is the level of regulation of heat consumption directly on heating devices that is the closing link in the energy saving chain. After all, if any end consumer has reduced his heat consumption, it should automatically be reduced for the building as a whole, for the central heating district, and so on, along the chain.

In addition, you need to understand that each person has his own ideas about comfortable temperature air. And for many it does not exceed 18-21°C. If the room is warmer, and there is no thermostat on the heater, then the consumer will inevitably open the window. Those. the idea of energy saving is again emasculated.

Needless to say, no valve or ball valve is simply physically capable of performing the functions that a thermostat takes on, and does not allow you to get the same energy-saving effect. Not surprisingly, in recent years, some manufacturers, such as the Moscow plant "Santekhprom", began to produce heating radiators with built-in thermostats.

6. Transition to apartment heat metering (for MKD)

In our table, the economic results from the use of automatic radiator thermostats and individual heat meters are combined into one indicator. This was not done in vain, because it is the introduction of apartment heat metering in MKD that most stimulates residents to save. If your neighbor does not care and he prefers to keep the heaters constantly heated to the limit, and regulate the temperature in the apartment by opening the windows, then why should you pay for this whim?

The problem is that, until recently, it was problematic to implement apartment heat metering in most Russian MKDs, where, as you know, mainly vertical heating distribution is used: it is too expensive to install a classic heat meter on each heating device, and they themselves do not have the necessary accuracy for work in a circuit with such a small temperature difference. However, the solution proposed by Danfoss - the INDIV AMR apartment heat metering system with automated remote wireless reading based on the use of radiator distributors - completely removes this issue.

The essence of the method is as follows. On each heating device in apartments without tie-in into the system is rigidly attached radiator distributor INDIV-3R with built-in radio module that measures the surface temperature of the heater. It is impossible to calculate heat transfer in this way, but by installing sensors on all heaters, you can fix the dynamics of temperature changes. And since the passport data (power, efficiency) of each heater are known, it is possible with a high degree accuracy to calculate the share of each of them in the total volume of consumption. Then the general house consumption is divided into 2 parts in accordance with the design standards: 35% refers to heating common areas and is distributed among the owners in proportion to the area of their apartments, 65% is divided between them in accordance with the shares determined using the INDIV-3R distributors. Distributors automatically transmit readings over the radio to floor receivers, those - to a home hub, and then, via Ethernet or GSM - to remote computer dispatcher.

In Russia system testingINDIVAMR was carried out at a number of facilities, incl. - in house number 59 on Obruchev street in Moscow. The result of its implementation is clearly shown in the diagram. Except for 11 apartments where the system individual accounting was not established and consumption for which was calculated according to the standard scheme (these apartments are clearly distinguished on the diagram), then the vast majority of owners in 2010 significantly reduced their consumption compared to the average level of 2009, and some - by 60-70%!

By the way, the INDIV AMR system is certified in the GOST R system and is included in the Register of Measuring Instruments.

Elementary logic and test results speak of the same thing - the need to implement comprehensive energy-saving measures. Any half-hearted solutions will give a half-hearted result, i.e. spread the economic effect over time, making investments in energy conservation of little interest.

* The potential for reducing the payment for consumed heat resources by installing a heat meter usually lies within 5-10% of payments under the contract. However, it should be noted that it is not uncommon that the installation of a metering unit led to an increase in the total cost of thermal energy due to incorrect operation of the heat supply organization, incorrect determination of design heat loads, insufficient thermal insulation of the building, etc.

* * Carrying out measures to insulate the building and thermal insulation of communications in itself does not save thermal energy, but allows you to achieve the effect only in conjunction with automation heating point and modernization internal system building heating.published

A group of leading industry and academic institutions in the field of electric power industry (ENIN named after Krzhizhanovsky, VTI, etc.) has developed a program "Modernization of thermal power plants for the period up to 2030". In the section "Heat supply and heating network» of this document, target indicators are given that give an idea of the ways of modernization, the structure of heat production and some features of the construction of heat networks in the coming years.

The long-term forecast for the production and consumption of thermal energy takes into account the widespread implementation of measures to save heat transport: it is expected that until 2030, the production of thermal energy will increase annually by 0.35-0.6%, and consumption - by 0.9-1, one %. In other words, the difference between production and consumption (ie transport losses) will gradually decrease.

The total production of thermal energy in 2005 was 1977 million Gcal, and by 2020 this figure is expected to increase to 2000 million Gcal. The structure of production will not change significantly: in 2020, as in 2005, the main amount of thermal energy will be supplied to consumers by thermal power plants and large boiler houses (with a capacity of more than 20 Gcal/h). Significantly less, as at present, will be the share of autonomous heat sources, small boiler houses (less than 20 Gcal/h) and non-traditional heat sources.

Much attention in the subprogram "Modernization of thermal power plants" is paid to the issue of improving and increasing the reliability of thermal networks (see RCM No. 4 (14) 2012), the total length of which is Russian Federation already now is more than 172 thousand km. The main type of laying of heat networks (more than 90% of the total length) is underground laying in impassable and through channels. Not only today, but also in the future, channel laying will remain the main type of construction of heat pipelines. But preference in the modernization of heating networks will be given to industrial prefabricated structures.

When laying main pipelines, pre-insulated polyurethane foam (polyurethane foam) pipelines with a system of operational remote control will be used. For heating networks with a diameter of up to 400 mm, preference will be given to pipelines in PPU or PPM (foam polymer-mineral) insulation, and for heating pipelines after the central heating station - flexible pipes Casaflex produced by the Polymerteplo Group or similar from other manufacturers. Flexible pipe systems made of of stainless steel in polyurethane foam insulation are designed for underground channelless laying of heating systems. Operating pressure such pipes - 1.6 MPa, working t - up to 160 °C (Fig. 1).

Fig.1

Isoproflex flexible pipes will be widely used for hot water pipelines. These are pipes made of cross-linked polyethylene in polyurethane foam insulation with a working temperature of 95 ° C and a maximum pressure of 1.0 MPa (Fig. 2).

Fig.2

For the production of pipes in industrial insulation, there are already more than 100 enterprises in almost all federal districts. The total production capacity of these enterprises is more than 10,000 km of pipes per year. But for now loading production capacity ranges from 30 to 60%.

On fig. Figure 3 shows pre-insulated polyurethane foam pipelines in a complete set, ready for installation, for channelless laying and in a galvanized sheath (Fig. 4) - for above-ground laying. The service life of heating mains with such pipelines increases to 30-40 years, and heat losses are reduced to 2%. It is clear that such a design of heat pipelines should significantly reduce fuel and electricity consumption. It is calculated that with a pipe diameter of 1020 mm, this reduction per 1 km of networks will be 0.106%, and with a diameter of 530 mm - already 0.217%. The temperature drop in the first case will be only 0.05 °C/km, in the second - 0.12 °C/km, and with a diameter of 219 mm - 0.46 °C/km.

Fig.3

Fig.4

The time for laying a heating main when using such heat pipelines is reduced by 3-4 times, capital costs are reduced by 15-20%, and repair costs are reduced by 3 times. But, perhaps, the most important advantage of such heating networks is that due to the mandatory installation of a system for operational remote monitoring of the dampening of thermal insulation (SODK), the accident rate of heating mains is practically eliminated.

MOEK - Moscow United Energy Company - can serve as an example of a responsible approach to solving the problem of reliability of heat pipelines. The investment project "Reconstruction of heating networks", launched by this company several years ago, involves the use the latest technologies. These technologies can dramatically reduce operating costs and extend the service life of pipelines up to 30-40 years compared to 8-12 years when using traditional technologies. Special attention will be given to heat networks with pipes of small diameter, which account for 96% of all cases of damage to heat networks.

A heat substation can be used to modernize old buildings, provided that not only heat substations, but also heat exchangers and other related equipment are replaced. When constructing a new building, it is more profitable to design a heat point and introduce the installation of an individual heat point, since in the future this will significantly reduce the total cost of the project by reducing capital costs and the cost of laying heating networks.

Modernization of heat points is carried out to improve the heat supply of the building in accordance with modern requirements. The main tasks of modernization are the organization of accounting for heat consumption by the subscriber and the reduction of heat energy consumption while improving the level of thermal comfort in the serviced premises. To do this, at least a metering device and an automatic regulator are installed at the subscriber input. heat flow, correcting the release of heat according to weather conditions. This application of equipment is called local or subscriber automatic control. At the same time, they do not carry out structural changes in the heating system, but provide for this possibility in the future. This is especially true for decisions on the use of a hydraulic elevator with an adjustable nozzle (14.9). At first glance, it solves the tasks set, but with the subsequent modernization of the heating system by installing thermostats on heating devices in accordance with the program of the Cabinet of Ministers of Ukraine, it will need to be abandoned.

Modernization of subscriber inputs allows:

optimize the distribution of heat load in the heating network;

adequately manage the hydraulic and thermal regimes of the internal heat consumption system of the building;

reduce the consumption of coolant in the heating system;

save energy resources;

reduce the negative impact on the environment.

When modernizing a heating point, many tasks are considered

The most frequently solved tasks:

Automation of the control process, control, accounting of heat and coolant consumption:

regulation of the temperature of the heat carrier supplied to the heating system, depending on the outdoor temperature;

regulation of the temperature of the heat carrier returned to the heating system in accordance with the outside air temperature according to a given temperature schedule;

accelerated heating ("natop") of the building after the energy-saving mode (reduced heat consumption);

correction of the mode of heat consumption according to the air temperature in the room;

limiting the temperature of the coolant in the supply pipeline of the heating system;

regulation of heat load in the hot water supply system;

regulation of the heat load of supply ventilation

installations providing anti-freeze function (14.10);

regulation of the magnitude of the decrease in heat consumption in specified periods according to the outdoor temperature;

regulation of the heat consumption mode, taking into account the accumulating features of the building and its orientation to the cardinal points.

These processes in the heat point change the heat consumption mode of the subscriber: from a qualitative mode to a qualitative-quantitative one. From a hydraulic point of view, this is the transition from a constant hydraulic regime (14.11) to a variable one (14.12). From a technical point of view -

this is the replacement of equipment that is unable to work in new hydraulic conditions with equipment that solves the tasks. The equipment to be replaced primarily includes the hydraulic elevator (14.7). Replacing the hydraulic elevator (14.7) with a pump makes it possible to implement many energy-saving functions of automatic control of the heat consumption of the building both at the time of the modernization of the heating point and during the subsequent modernization of the heating and hot water supply system.

14.3. AUTOMATION OF EXISTING HEAT POINTS

Before replacing the equipment of a heating point, it is necessary to carry out a detailed technical and thermal-hydraulic examination, during which the actual state of the subscriber input is clarified. This determines:

design and actual coolant costs;

design and actual hourly and monthly heat loads;

design and actual parameters of the coolant at the inlet - average values and their deviations both in the working and in emergency mode work of the heating system;

the presence of deposits on the inner surfaces of pipes and fittings;

the presence in the pipes of stray currents, potential differences and vibrations;

interference sources for electronic devices;

power stability.

The indicated data are obtained both by the calculation method and by the method of direct measurements. Thus, the coolant flow rates in the calculation method are determined according to the design loads and the temperature schedule; with direct flow - an ultrasonic flow meter with clamp-on sensors. For closed systems in the latter case, the flow rates in the supply and return pipelines should be determined to detect unauthorized analysis of network water or leaks.

Thermal loads are determined by temperature regime source of heat supply and the temperature regime of the heating system. According to the piezometric graph of the pressure of the heat carrier of the heating network in static and dynamic modes, the design parameters of the coolant at the inlet to the building are determined and compared with real indicators on pressure gauges. Information about the content of air and gases, mechanical and suspended particles in the coolant allows you to choose the right heat meter. Such an analysis is carried out on deposits in pipes and sumps. Attention should be paid to the presence of magnetites in the coolant, which increase the error of electromagnetic flowmeters. The presence of mechanical particles in the coolant is unacceptable when using rotary heat meters, pumps and automatic valves.

Stray currents and electrochemical corrosion can cause unsatisfactory operation for flow and temperature sensors of the coolant, as well as the heat meter. Vibration significantly affects the operation of vortex flowmeters. The instability of the power supply predetermines the choice of a heat meter with batteries. It also affects the location of the stem of automatic valves in the absence of electricity - closed, intermediate - fully open. Forces to install local backup source power supply, or leave the hydraulic elevator (14.7) as a backup option for the mixing unit with the pump. Based on the information received, a subscriber input scheme is selected, appropriate equipment is selected, and its performance is ensured. Then the stages of work execution are determined. Automation of heat points is carried out by:

step by step;

in one step.

Phased modernization is used in the absence of one-time funds for full automation. Often, this path is implemented with the further replacement of the dependent connection of the subscriber to the heating network with an independent one. At the first stage, a heat meter and a pump are installed, or only a heat meter. On the second - a plate heat exchanger and automatic valves. Taking into account the domestic standard, an automatic heat flow controller should be installed at the first stage.

When installing pumps, the hydraulic elevator can be dismantled or left. In the first variant, the hydraulic elevator is replaced with a branch pipe and a plug is installed on the mixing pipeline or it is cut off, and a pump piping assembly with a jumper is cut into the supply or return pipeline. In addition, after the pumps, a manual control valve is installed to adjust the heating system using the temperature method, and a strainer is installed in front of the pumps. In the second case, the pump piping unit with a control valve and a filter is placed parallel to the hydraulic elevator (Fig. 14.5).

Fig.14.5. Parallel placement of the pump unit to the hydraulic elevator

The filter should be placed after the jumper, which provides filtration of both network and mixed water. On the jumper should be installed check valve(14.13) to prevent the overflow of network water into the return pipeline. The tie-in of the supply pipeline after the pumps is carried out behind a valve that turns off the heating system, which, when the pumps are running,

should be closed. In addition, a plug is installed between the flanges of the hydraulic elevator connection to the mixing pipeline. Best Option modernization of a heating point is its automation in one stage. This is the way they went in Kyiv when replacing heat points public buildings. The implemented approach is shown in fig. 14.6. The engineering systems of the building remain unchanged during the automation of the heating point. However, their further modernization is possible by installing automatic temperature controllers on the piping units of the heating devices of the heating system and installing temperature controllers on the circulation pipelines of the hot water supply system.

Fig.14 6 Scheme of replacement of nodes during the modernization of the heating point

Such modernization becomes possible, since pumps are the driving force behind the movement of water in these systems. In addition, mesh filters are installed in the new units, which reduce the contamination of the coolant.

In the old heating point, almost all equipment is dismantled (Fig. 14.7): instrumentation, metering unit, high-speed water heaters, elevator unit. Leave only valves and sumps. Moreover, upon request, a sump on the return pipeline is installed in front of control devices, as well as water and heat flow metering devices. New connection points for heating systems (Fig. 14.7, b) and hot water supply are designed in accordance with local conditions.

When modernizing heat points under the program of the European Bank for Reconstruction and Development in Kyiv, a dependent scheme for connecting a heating system without a bypass valve (14. 14) and a two-stage mixed scheme for connecting a hot water supply system with plate heat exchangers are used. In addition, at the heating point, water drainage from the pit is automated.

New system connections often have factory production and are delivered to the facilities assembled in the form of a block heat point. The unit is supplied with welded pipes to counter flanges, which facilitates installation work.

When modernizing heat points, in the vast majority of cases it is advisable to use block heat points. They are assembled and tested in the factory, they are reliable. Installation of equipment is simplified and cheaper, which ultimately reduces the cost of modernization.

The modernization of the heating point is carried out on the basis of a detailed technical and thermal-hydraulic survey of the subscriber input.

Rice. 14.7 General form subscriber input: a - before modernization; b - after modernization