Ecology of consumption. Science and technology: When introducing energy-saving measures, half-measures, despite a one-time reduction in capital costs, pay off for a long time and difficultly, but complex measures allow you to return the money and make a profit much faster
Modernization of heating systems of multi-apartment residential buildings and social infrastructure facilities is one of the most pressing topics for utility industry professionals 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 in energy services?” Practice proves: half-hearted measures, despite a one-time reduction in capital costs, pay off over time and with difficulty, while complex measures allow you to return the money and make a profit much faster.
So, let’s consider sequentially the complex of measures being implemented today at housing and communal services facilities aimed at reducing the heat consumption of utility facilities (including apartment buildings) and their effectiveness.
|
Energy efficient measures and their essence |
Average savings |
||
|
1 |
Installation of heat metering unit |
Without accounting, talking about savings and payback is pointless. |
* |
|
2 |
Elimination of heat loss |
Insulation of building envelopes, entrances and basements, thermal insulation of communications. |
** |
|
3 |
Modernization of the heating unit |
Replacement of elevator units with AITP or AUU, depending on the scheme of connecting the facility to the heating network. Setting up the AITP controller for a reduced heating schedule at night, weekends and holidays (especially relevant for administrative buildings and educational institutions). |
15-25% |
|
4 |
Balancing the system by risers |
Installation of automatic balancing valves to equalize the coolant flow along risers at different distances from the thermal input. |
5-10% |
|
5 |
|
Installation of automatic radiator thermostats on all heating devices, or replacement of heating devices with new ones with built-in thermostats. |
10-15% |
|
6 |
|
For buildings with horizontal apartment-by-apartment distribution of the heating system, install a heat meter at the entrance to the apartment. For houses with vertical wiring - the introduction of alternative accounting systems, for example,INDIV AMR. |
|
|
TOTAL: |
30-50% |
||
Now let’s evaluate the most common mistakes that are made locally during the planning and implementation of heat conservation measures.
1. Installation of heat metering unit
Fortunately, the necessity of this step today no longer raises any doubts, 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 simply installing a heat meter. Hypothetically, these expectations may be justified: sometimes it turns out that a building consumes less heat than required by the standard, and then after installing a heat meter, the amount of heating payments is reduced. But this is a lottery, making a rule out of this is a big mistake. You need to understand well: a meter is just a measuring tool that in itself does not save anything.
2. Elimination of heat loss
It is produced according to need, which, in theory, should be determined during an energy survey. Unfortunately, the inspection is not always carried out; as a result, at some facilities, the necessary overhaul is either not carried out at all, or thermal gaps remain, which can sometimes negate the effect of subsequent measures. The cost of such a mistake is high: in approximately 10-15% of cases, instead of saving, you end up with a direct loss. This is not surprising, because if in a house with leaky walls you install an automatic system that will unsuccessfully try to heat it, and a heat meter, then the readings of the latter, of course, will go off scale. And calling the supposedly low efficiency of energy-saving measures as the reason for this result is completely wrong.
Another common mistake is expecting savings from insulating a building without upgrading the heating system. If you have an elevator in the basement, then the heat consumption will always be the same, regardless of whether the walls keep warm or freeze through, because... This flow rate depends only on the mixing coefficient 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 consumption. Its inhabitants will have only one option: open the windows and let out excess heat outside, still paying for it in full. It is those excesses that the automation allows you to cut off at the inlet, before 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 Moscow Government and MNIITEP on the basis of three real residential buildings No. 51, 53 and 59 on Obrucheva Street in Moscow. Beginning in 2008, all three buildings underwent reconstruction as part of the city's capital renovation program, including the installation of hinged ventilated facades and the installation of plastic windows. Thus, they all fully complied with modern thermal insulation standards. At the same time, in house No. 51 no work was carried out to modernize the heating system. 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 house No. 59, where a comprehensive reconstruction of the heating system was carried out, heat consumption was reduced by 44.6%.
3. Modernization of the heating unit
From the above, a simple conclusion follows: elevator schemes and energy saving are incompatible things. Therefore, if you want to save money and also provide building occupants with the opportunity to maintain a comfortable microclimate in the premises, then the elevator heating unit must be replaced with an automated one. If the facility is connected to the heating network according to an independent scheme, it is an automated individual heating point (AITP) with a heat exchanger. If the connection is dependent, then the automated control unit (ACU), i.e. scheme with pump mixture. In principle, the same heating 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 of the temperature schedule, i.e. regulation depending on internal heat consumption. Both schemes provide forced circulation of coolant in the system.
IN last years many utility companies are trying to promote the idea of using the so-called. economizers - adjustable electronic hydraulic elevators. Their design is a little more complicated than conventional ones: the electronic unit, connected to an outside air temperature sensor, controls a simple electromagnetic drive, which pushes a needle into the jet pump nozzle, 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 they are practically the same device. That's why:
- You will not be able to use radiator thermostats and balancing valves in the system, because... any elevator is a low-power device and the additional hydraulic resistance is beyond its strength;
- 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"), whereas 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 are three to four times less than the required value;
- If for some reason the heating network does not maintain the temperature schedule, then either overflow or underflow occurs at the facility, because the flow rate in the system is constant, and the hydraulic elevator is a passive device. If, due to the “overgrowing” of old pipes with deposits, the hydraulic resistance of the system increases, then the house becomes cold;
- 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 point, no matter what the outside temperature is, heating batteries continue to be hot. The consequences are known: stuffiness, the windows are wide open, the “extra” heat is used to heat the street, but you still have to pay money for it. What a savings!
There is one more fly in the ointment. Even an eighth-grader understands that when the area of the nozzle of an adjustable elevator decreases due to the introduction of a needle into it, the jet at the exit from this nozzle becomes less powerful, and therefore the force of suction of water from the return pipeline of the heating system decreases. Those. The more the needle moves into the nozzle, the less coolant flow in the system becomes, in other words, the circulation of water in the heating circuit slows down. And at some point, this flow 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 rapidly cool down.
4. Balancing the system
For some reason, the modernization of the heating system is often 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 along some risers, and underheating occurs along others at the same time. In MKD this is usually corner apartments, the last in the chain. If you regulate according to them, then in the intermediate ones there will be overflow and constantly open vents. 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 thermoelements, thanks to which the AB-QM automatic balancing valves begin to regulate the coolant flow through the risers depending on changes in the return coolant temperature. This technology has made it possible to bring one-pipe heating systems closer to two-pipe ones in terms of energy efficiency.
In 2009, during an experiment on Obruchev Street in Moscow, in houses No. 53 and 59, elevator thermal units were replaced with automated control units (ACU)Danfoss with weather-compensated control (implemented using universal controllersECLComfort) and automatic radiator thermostats were installed on all heating devices in the apartments. At the same time, 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-Q.M. In 2010, the balancing of the system in house No. 59 was brought to logical conclusion by equipping valvesAB-QM thermocouplesQT.
As a result, for house No. 53 (without balancing) a decrease in heat consumption was recorded by 33.8%, while for house No. 59 (with balancing) - by 44.6%, as mentioned above. That is, even in a single-entry building, balancing gives a quite tangible economic effect. Moreover, in the winter of 2010-2011, after installing thermostatic elementsQT, consumption decreased compared to the level of 2009-2010. by almost 12% (or 7.5% compared to the level of 2008-2009), which proves the justification of the use of this technology.
5. Equipping heating appliances with individual control means
Very often we hear that this measure is not mandatory and only creates additional comfort for the occupants of the building, without providing any savings. Firstly, even in this case it would be worth implementing, 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 user has reduced its 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 air temperature. And for many it does not exceed 18-21°C. If the room is warmer and there is no thermostat on the heating device, the consumer will inevitably open the window. Those. The idea of energy saving is being emasculated again.
Needless to say, no valve or ball valve is simply physically capable of performing the functions that a thermostat undertakes and does not allow obtaining the same energy-saving effect. It is not surprising that in recent years some manufacturers, for example, the Moscow Santekhprom plant, have begun to produce heating radiators with already built-in thermostats.
6. Transition to apartment-by-apartment heat metering (for apartment buildings)
In our table, the economic results from the use of automatic radiator thermostats and individual devices heat accounting are combined into one indicator. This was not done in vain, because it is the introduction of apartment-by-apartment heat metering in apartment buildings that most stimulates residents to save. If your neighbor doesn’t care and prefers to keep the heating devices constantly heated to maximum, and regulate the temperature in the apartment by opening the windows, then why should you pay for this whim for him?
The problem is that until recently, implementing apartment-by-apartment heat metering in most Russian apartment buildings, where, as is known, mainly vertical heating distribution is used, was problematic: installing a classic heat meter on each heating device is too expensive, and they themselves do not have the necessary accuracy for operation 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 eliminates this issue.
The essence of the method is as follows. On each heating device in apartments without a connection to the system, an INDIV-3R radiator distributor with a built-in radio module is rigidly mounted, measuring the surface temperature of the heating device. It is impossible to calculate heat transfer in this way, but by installing sensors on all heating devices, it is possible to record the dynamics of temperature changes. And since the passport data (power, efficiency) of each heating device is known, it is possible to calculate with a high degree of accuracy the share of each of them in the total consumption. Then general house consumption is divided into 2 parts in accordance with design standards: 35% goes to heating common areas and is distributed among the owners in proportion to the area of their apartments, 65% is divided among them in accordance with the shares determined using the INDIV-3R allocators. Distributors automatically transmit readings via radio to floor receivers, which to the house hub, and then, via Ethernet or GSM, to the remote dispatcher’s computer.
System testing in RussiaINDIVAMR was carried out at a number of sites, incl. - in house No. 59 on Obruchev Street in Moscow. The result of its implementation is clearly presented in the diagram. Except for 11 apartments where an individual metering system was not installed and consumption for which was calculated according to standard scheme(these apartments clearly stand out in the diagram), then the vast majority of owners in 2010 significantly reduced their consumption compared to the average level of 2009, 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 about the same thing - the need to implement comprehensive energy-saving measures. Any half-hearted solutions will give half-hearted results, i.e. will spread the economic effect over time, making investments in energy saving uninteresting.
* The potential for reducing payments 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 there are often cases when 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 does not in itself save thermal energy, but can achieve the effect only in conjunction with automation of the heating point and modernization of the internal heating system of the building. published
A heating point can be used to modernize old buildings, provided that not only heating points are replaced, but also heat exchangers and other related equipment. When constructing a new building, it is more profitable to design a heating unit and implement the installation of an individual heating unit, since in the future this will significantly reduce the overall cost of the project by reducing capital costs and the cost of laying heating networks.
The modernization of heating points is carried out to improve the heat supply of the building in accordance with modern requirements. The main objectives of the modernization are to organize metering of heat consumption by the subscriber and reduce thermal energy consumption while improving the level of thermal comfort in the serviced premises. To do this, at a minimum, a metering device is installed at the subscriber input and automatic regulator heat flow, corrective heat release according to weather conditions. This use of equipment is called local or subscriber automatic regulation. At the same time, they do not make structural changes in the heating system, but provide for this possibility in the future. This is especially true for decisions to use a hydraulic elevator with an adjustable nozzle (14.9). At first glance, it solves the problems, 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 building’s internal heat consumption system;
reduce coolant consumption in the heating network;
save energy resources;
reduce negative impact on the environment.
When modernizing a heating point, many tasks are considered
Most frequently solved problems:
Automation of the control process, control, accounting of heat and coolant consumption:
regulation of the temperature of the coolant supplied to the heating system, depending on the outside air temperature;
regulation of the temperature of the coolant returned to the heating network in accordance with the outside air temperature according to a given temperature schedule;
accelerated heating (“heating”) of the building after an energy-saving mode (reduced heat consumption);
correction of heat consumption mode based on room air temperature;
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 with frost protection function (14.10);
regulation of the amount of heat consumption reduction in specified periods based on the outside air temperature;
regulation of heat consumption, taking into account the accumulating features of the building and its orientation to the cardinal points.
These processes at the heating point change the heat consumption mode of the subscriber: from a qualitative mode to a qualitative-quantitative mode. From a hydraulic point of view, this is a transition from a constant hydraulic mode (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 assigned tasks. The equipment being replaced primarily includes a hydraulic elevator (14.7). Replacing the hydraulic elevator (14.7) with a pump allows you to implement many energy-saving functions of automatic control of the building’s heat consumption both at the time of modernization of the heating point and during the subsequent modernization of the heating and hot water supply system.
14.3. AUTOMATION OF EXISTING HEATING STATIONS
Before replacing the equipment of a heating point, it is necessary to carry out a detailed technical and thermal-hydraulic inspection, during which the actual condition of the subscriber input is determined. This determines:
design and actual coolant costs;
design and actual hourly and monthly heat loads;
design and actual parameters of the coolant at the input - average values and their deviations both in operating and emergency operating modes of the heating network;
the presence of deposits on the internal surfaces of pipes and fittings;
the presence of stray currents, potential differences and vibrations in the pipes;
sources of interference for electronic devices;
power supply stability.
The specified data is obtained using both the calculation method and the method of direct measurements. Thus, coolant flow rates using the calculation method are determined by design loads and temperature schedule; for 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 identify unauthorized tapping of network water or leaks.
Thermal loads are determined by temperature conditions source of heat supply and temperature conditions of the heating system. Using the piezometric graph of the coolant pressure of the heating network in static and dynamic modes, the design parameters of the coolant at the entrance 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. This analysis is carried out on deposits in pipes and mud ponds. Attention should be paid to the presence of magnetites in the coolant, which increase the error of electromagnetic flow meters. 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 performance for coolant flow and temperature sensors, as well as a heat calculator. Vibration significantly affects the operation of vortex flowmeters. Instability of the power supply predetermines the choice of a heat meter with batteries. It also affects the position of the stem of automatic valves in the absence of electricity - closed, intermediate - completely open. Forces you to install a local backup 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 operation is ensured. Then the stages of work are determined. Automation of heating points is carried out by:
step by step;
in one stage.
Phased modernization is used in the absence of one-time funds for full automation. This path is often implemented when further replacing the subscriber’s dependent connection to the heating network with an independent one. At the first stage, a heat meter and a pump, or only a heat meter, are installed. On the second there is a plate heat exchanger and automatic valves. Taking into account domestic standards, an automatic heat flow regulator should be installed at the first stage.
When installing pumps, the hydraulic elevator can be dismantled or left. In the first option, the hydraulic elevator is replaced with a pipe and a plug is installed on the mixing pipeline or it is cut off, and a pump piping unit with a jumper is cut into the supply or return pipeline. In addition, a manual control valve is installed after the pumps 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 assembly with a control valve and 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 ensures filtering of both mains and mixed water. The jumper should be installed check valve(14.13) to prevent the flow of network water into the return pipeline. The insertion of the supply pipeline after the pumps is carried out behind a valve that turns off the heating system, which when the pumps are operating
must be closed. In addition, a plug is installed between the flanges of the hydraulic elevator connection to the mixing pipeline. The best option modernization of a heating point is its automation in one stage. This was the route taken in Kyiv when replacing heating points public buildings. The implemented approach is shown in Fig. 14.6. The engineering systems of the building remain unchanged when the heating point is automated. However, their further modernization is possible by installing automatic thermostats on the piping units of heating devices of the heating system and installing thermostats on the circulation pipelines of the hot water supply system.
Fig. 14 6 Scheme for replacing components when modernizing a heating unit
Such modernization becomes possible because pumps are the drivers of water movement in these systems. In addition, new nodes have mesh filters, reducing contamination of the coolant.
In the old heating station, almost all the equipment is dismantled (Fig. 14.7): instrumentation, metering unit, high-speed water heaters, elevator unit. Only valves and mud traps are left. Moreover, upon request, a mud trap is installed on the return pipeline in front of control devices, as well as meters for metering water flow and heat flows. New connection points for heating systems (Fig. 14.7, b) and hot water supply are designed in accordance with local conditions.
When modernizing heating points under the program of the European Bank for Reconstruction and Development in Kiev, a dependent connection scheme for the heating system without a bypass valve (14. 14) and a two-stage mixed connection scheme for the hot water supply system with plate heat exchangers are used. In addition, the heating point automates the drainage of water from the pit.
New system connection points often have factory production and are delivered to sites assembled in the form of a block heating unit. The block is supplied with pipes welded to the mating flanges, which facilitates installation work.
When modernizing heating units, in the vast majority of cases it is advisable to use block heating units. They are assembled and tested in factory conditions and are reliable. Equipment installation 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 examination of the subscriber input.
Rice. 14.7 General form subscriber input: a - before modernization; b – after modernization
Imagine that the renovation in your house or apartment has come to an end, all the pipes have been laid, plumbing fixtures have been installed, heating modernization completed. At this moment, you really want to be completely sure that all the costs and efforts will save you and your family members from negative impact cold in the winter season. In order to be completely sure efficient work The heating system will have to wait until the first serious frosts.
Unfortunately, various shortcomings that were made at the design stage or during the installation of the heating system do not appear immediately. If such shortcomings are discovered at the stage of work execution, the chances of achieving the desired result increase markedly.
If you do not want to devote time in the future to various problems that will arise after starting the heating system, we recommend contacting the Plumber Stepanych company. Our craftsmen clearly understand how heating systems should be updated. They have extensive experience, so they can guarantee high quality work.
Professional heating system modernization will help you avoid such problems. The specialists of the Plumber Stepanych company begin work only after the corresponding project has been drawn up. For the most comfortable stay, we recommend paying attention to water-heated floors. Please note that if the customer lives in an apartment, the heating can be upgraded only minimally. As a rule, the essence of the work is to install pipes that are more efficient in terms of functionality and replace heating radiators.
Owners of private houses have more serious opportunities for modernization. This means that the design of heating systems at such facilities requires a more careful approach. Experts take into account the area, layout of the property, the height of the ceilings in the house, as well as the characteristics of the walls. Only after this can the required power of the heating system be determined.
Very often those systems that were developed several decades ago are subject to modernization. The use of the latest technologies in this area makes it possible to achieve much more best results, reducing the cost of operating the system.
Photos of heating modernization work:
print version
Approval of the work plan for major repairs, the timing and procedure for their production, the estimated cost of funding sources is carried out by decision general meeting owners of premises in apartment buildings (Article 184 of the Housing Code of the Russian Federation). Managers of management organizations, homeowners' associations and housing cooperatives must bring to the attention of owners objective information about the advisability of modernizing a particular engineering system during the repair process.
Making a decision about modernization utility networks MKD
When organizing a major overhaul (CR) in the constituent entities of the Russian Federation, for example in St. Petersburg, attention was paid to clause 9 of Art. 29 of the Law of July 27, 2010 No. 190-FZ “On Heat Supply”, which states: “From January 1, 2022, the use of centralized open systems heat supply (hot water supply) for the needs of hot water supply, carried out by selecting coolant for the needs of hot water supply, is not allowed.”
It is obvious that when planning work on the Kyrgyz Republic, it is necessary to provide for and enshrine in the regulatory acts of the constituent entity of the Russian Federation an event to fulfill this requirement.
At the same time, a good owner is interested in simultaneous modernization of hot water supply (DHW) and heating systems. But this is not only a technical issue, but also an economic one.
To make a decision on the Kyrgyz Republic engineering systems hot water supply and heating should be determined:
Compliance with federal regulations;
Technical necessity;
Economic feasibility.
Let's consider alternative solutions for apartment buildings, in individual heating points (ITP) of which elevator units are installed.
Through the elevator units, the coolant is transferred to the heating system, and to the hot water supply system - through the thermostat in the ITP.
The following system repair options are possible:
Modernization of the hot water system without affecting the heating system;
Replacement of an outdated elevator unit with a unit with automatic temperature control and modernization of the hot water supply system;
Replacement of the elevator unit with an automated one and modernization of hot water supply and heating systems.
If gas heaters are used, there is no thermostat in the ITP. We are not considering modernizing such hot water supply systems.
Modernization of the DHW system
At the entrance of the heating network pipelines to the MKD elevator unit, a thermostat is installed, through which water with a temperature of 65-70 °C is supplied to the hot water system. Thus, for the needs of hot water supply, coolant is taken from the heating network. Please note that from January 1, 2022, such a scheme will be prohibited.
There is practically only one solution - a device closed system DHW with the installation of heat exchangers and pumps in the ITP, as well as the replacement of galvanized steel pipes with polymer ones.
Design and estimate documentation must determine:
Composition and design of the water heating circuit;
Composition and routing of internal pipelines;
A pumping unit that ensures water circulation in the system;
Automation that regulates the temperature of hot water and timely replenishment of the system;
Compensation for thermal linear expanders of polymer pipelines.
Conclusion. During the Kyrgyz Republic, functionally outdated technical solutions should be updated and new materials should be used in accordance with the requirements of current standards. This will improve the consumer qualities of the DHW system.
Modernization in this case is caused by new technical requirements. Their implementation is mandatory, which excludes the prevailing role of economic assessment.
However, the cost polymer pipes three times less, and the service life is higher than that of the galvanized steel they replace. Although the modernization of the hot water supply system during the Kyrgyz Republic is not included in the list of works provided for in Part 1 of Art. 166 Housing Code of the Russian Federation.
Based on Part 2 of Art. 166 of the Housing Code of the Russian Federation, the specified work can be included in the work on the CR of common property in MKD, financed from the funds of the CR fund, formed on the basis of minimum size contribution only by a regulatory legal act of a constituent entity of the Russian Federation.
Concluding the question about the control system of the hot water supply system, powered through a thermostat at the input of the heating network to the elevator unit, it should be recognized as necessary to modernize it according to the indicated scheme. The decision on modernization must be made by the subject of the Russian Federation and formalized by the relevant regulatory act.
Replacing the elevator unit with an automated one
Modernization of the hot water supply system, isolated from the elevator unit and having an ITP independent block heating and circulation of hot water, led to the desire to install an automated unit for supplying coolant to the heating system.
Let us consider to what extent such a replacement is technologically necessary and economically feasible.
The elevator unit is the simplest and most reliable unit. It does not require maintenance or operating costs over a long period of time. At the estimated outside air temperature (in St. Petersburg - 26 °C), superheated water with a temperature of 150 °C under high pressure enters the elevator unit. The pressure drops to 6 bar and the temperature to 95 °C. In this case, only in remote sections of the heating network may it be necessary to install booster pumps in the ITP.
At modern construction high-rise apartment buildings cannot be built without booster pumps. The installation of automated coolant supply units with their own pumps is justified by technological necessity and modern requirements for adjusting coolant parameters.
An automated coolant supply unit is necessary for the operation of the heating system in high-rise apartment buildings.
Replacing elevator units with automated ones is not caused by technological necessity and can be considered as modernization. Installation of automatic pressure and temperature control systems in pipelines (automated control unit) in clause 1.4 Methodological recommendations to Federal Law No. 185-FZ “On the Fund for Assistance to the Reform of Housing and Public Utilities” refers specifically to the modernization of ITP.
Given the limited financial resources of the Kyrgyz Republic, this recommendation should become an indispensable requirement.
The main purpose of the automated unit is not to save thermal energy, but to ensure that the calculated amount is supplied to the heating system to create comfortable conditions in the premises in accordance with sanitary standards at any outside temperature. If excess heat is supplied to the ITP, this excess does not enter the heating system and is not recorded by metering devices.
An automated unit with a closed heating circuit allows the system to operate at any number of floors in the building, regardless of the pressure in the heating network at the inlet to the ITP.
Some experts involved in the promotion of automated units believe that their installation will allow for up to 20% savings in thermal energy by blocking the access of excess heat to the heating system.
Such savings can only be obtained in an administrative building, where the air temperature in the premises can be reduced during non-working hours to +8-10 °C.
In MKD, significant savings can only be made in certain periods (days, months), but not on average over the heating period.
EXAMPLE
Back in 2008-2009. monitoring of the flow of thermal energy into one of the apartment buildings in St. Petersburg was carried out. The MKD is equipped with two ITP with elevator units: ITP-1 with a heat load of 0.7 Gcal/h and ITP-2 - 0.4 Gcal/h.
The design heat loss of the house for each ITP was determined at different temperatures outside air by calculation based on design data.
The actual heat consumption in each month was determined from the Heating Networks report based on meter readings.
The monitoring results are summarized in a table.
|
ITP-1 0.7 Gcal/h Overspending Short delivery |
ITP-2 0.4 Gcal/h Overspending Short delivery |
TOTAL around the house Overspending Short delivery |
||||
|
Overspending Short delivery |
||||||
Automation doesn't pay off
It is possible to assess the economic feasibility of upgrading ITP by replacing elevator units with automated coolant supply units for the heating system.
The cost of installing one automated unit with a heat load of 0.4 Gcal/h (for a 70-apartment building) is estimated at 1.3 million rubles. taking into account the creation of the project, acquisition of equipment, its installation and commissioning.
The table shows that through IHP-2 with the same heat load of 0.4 Gcal/h, excess heat in the amount of 10.02 Gcal entered the heating system. The cost of 1 Gcal at that time was 854 rubles.
The following amount could be saved by eliminating excess heat when installing an automated unit:
854 x 10.02 = 8557.08 rub.
Considering that the readings of excessive heat consumption as a percentage of the supplied heat differ significantly in ITP-1 from ITP-2, it is possible to determine the average amount of excess heat in the house per 0.4 Gcal of heat load:
103.33 x 0.4: (0.7 + 0.4) = 37.57 Gcal.
The cost of this heat is estimated at 32,085 rubles:
854 x 37.57 = 32,085.
This means that with capital costs of 1.3 million rubles. for the modernization of ITP-2, the expected economic effect is estimated at only 12-32 thousand rubles. for one heating season. The payback period is more than 40 years.
At the same time, one should not forget about operating costs. With an elevator unit there are practically none, but when operating pumps, heat exchangers, and automation, these costs will be very significant. Management companies, homeowners' associations and housing cooperatives will be forced to increase the costs of maintaining common property accordingly, which will inevitably lead to an increase in the price of maintenance and repair of apartment buildings.
From the table above it follows that in many months of the heating season there is a shortage of thermal energy in the ITP MKD.
This is explained by the fact that worn heating network cannot withstand coolant with high temperature and pressure parameters. Therefore, heat suppliers do not supply superheated water to the network in accordance with the schedule.
An automated unit designed for a certain heat load will not be able to compensate for the missing heat in a closed heating circuit if the temperature parameters of the coolant entering the ITP significantly deviate from the schedule.
In St. Petersburg, heating networks have been largely put in order, which allows us to hope that frequent cases of “underflow” and “overflow” will be eliminated.
Returning to the issue of excess heat and comfortable temperature in the premises of apartment buildings, we should remember the shut-off and control valves. In accordance with technical and sanitary standards, it must be installed in front of each heating device in a residential area.
The fittings installed back in Soviet times (double adjustment valves, three-way valves, DGI intersection valves, cast iron valves and plug valves) have practically become unusable due to long-term use, not always successful design and poor quality workmanship. In some houses, due to a shortage of fittings, it was not installed at all.
When the heating system is closed, modern shut-off and control valves must be installed in front of each heating device, for example Ball Valves. This, without any additional costs, will prevent excess heat from entering the device and maintain a comfortable temperature in the room.
Ensuring temperature control in each residential area of the apartment building and thereby reducing the total amount of excess heat entering the apartment building is relevant.
It must also be remembered that the replacement of elevator units with automated units is not included in the work on major renovation specified in Part 1 of Art. 166 Housing Code of the Russian Federation.
So, modernizing the ITP with replacing the elevator unit with an automated one is not necessary from a technological point of view, but is not economically feasible. Replacement of control valves in heating systems is necessary.
Heating system modernization
It is economically and technically attractive to replace steel pipelines with polymer pipes in the heating system.
Let's consider the economic feasibility of such modernization.
The fundamental conditions for the use of polymer pipes in heating systems are specified in clause 6.1.2 of SNiP 41-01-2003:
“In buildings with a central water heating system with pipelines from polymer materials should be provided automatic regulation parameters of the coolant in individual heating points at any heat consumption of the building. Coolant parameters (temperature, pressure) should not exceed 90 °C and 1.0 MPa, as well as the maximum permissible values specified in the manufacturer’s documentation.”
An automated coolant supply unit can provide all of the listed conditions necessary for the use of polymer pipes in a heating system.
In this case, polymer pipes must meet the following
requirements:
Comply with GOST R 53630-2009 “Multi-layer pressure pipes for water supply and heating systems”;
Be oxygen-tight (requirement of the specified GOST and SNiP 41-01-2003);
Have a certificate of conformity and, if necessary, a technical certificate from the Ministry of Construction of Russia.
To make a decision on replacing steel pipes with polymer ones during the heating system repair process, the economic feasibility of such a replacement should be determined.
The difficulty of this task lies in the lack of technically sound standards for the service life of polymer pipes. Thus, one of the developers of GOST R 52134-2003 “Pressure pipes made of thermoplastics and connecting parts for them for water supply and heating systems” State Unitary Enterprise “Research Institute Mosstroy” in a letter dated April 12, 2013 No. 44-07/242 reported that for multilayer polymer pipes that comply with GOST R 53630-2009, there is no method for determining their service life.
At the same time, the set of rules for design and construction (SP 41-102-98) states that the service life of metal-polymer pipes should be 25 years. This period mainly depends on the temperature of the coolant circulating in the pipes and the circulation time. Considering that these parameters are directly dependent on the outside air temperature during the heating season, we can conclude that the same polymer pipes will have different service life in different climatic zones. Unfortunately, there is no methodology for calculating the service life of multilayer polymer pipes.
EXAMPLE
Based on the reports of manufacturers, technical conclusions of the Ministry of Construction of Russia, the explanatory letter of the State Unitary Enterprise "Research Institute Mosstroy", it can be assumed that the guaranteed trouble-free service life of the most reliable polypropylene pipes with aluminum reinforcement will be about 20 years in the climatic zone of St. Petersburg.
The standard service life of steel pipelines in accordance with the Methodology for determining the physical wear and tear of civil buildings is 30 years.
Long-term practice of operating buildings with an open heating system using de-aerated water as a coolant indicates trouble-free operation of the heating system for at least 50 years.
For a correct comparison, let’s take into account the standard service life of polymer pipes is 20 years, and steel pipes - 40 years. At the same time, the pipelines of the heating system made of steel pipes will “outlive” two heating systems made of polymer pipes.
The estimated cost of a heating system made of polymer pipes is on average 1.8 times less than the cost of a heating system made of enlarged steel pipeline units.
Conclusion. One heating system made of steel pipes will be 10% cheaper than two systems made of polymer pipes.
In addition, you should take into account the cost of work on issuing design estimates for the use of polymer pipes with thermal and hydraulic calculations. It will be at least 15% of the cost of a heating system made of steel pipes.
The use of a coolant with a temperature of up to 90 °C instead of 95 °C will lead to an increase in the thermal power of heating devices, which in turn will increase the estimated cost of the heating system by up to 3%.
Thus, replacing steel pipes with polymer ones during the repair process will increase the cost of work by 28% and will lead to two repairs instead of one, which makes such a replacement economically infeasible.
Considering that both the replacement of the elevator unit with an automated one and the replacement of steel pipes with polymer ones are not economically justified, we can make an unambiguous conclusion about the economic inexpediency of modernizing the heating system based on such a replacement.
Technical risks
It is necessary to take into account the reliability of the heating system after modernization and the cost of capital and operating costs to ensure reliability.
When replacing the elevator unit with an automated one, there is a danger of stopping the pumps or malfunctioning the heat exchangers, which can paralyze the entire heating system and leave the entire house without heat.
To avoid such a situation, redundancy of pumps and heat exchangers and emergency supply of electricity are provided, and this all increases capital costs.
The uninterrupted operation of the automated unit is ensured by its qualified maintenance, systematic inspections and preventive maintenance, the presence of an emergency service, timely repair and replacement of equipment. All this leads to significant financial investments, which were not required before the installation of the automated unit.
A comparison of the reliability of steel and polymer pipes is not in favor of the latter.
In steel pipelines during long-term operation, leaks in threaded connections and drip leaks in problem areas. Such defects can be easily eliminated using modern sealing materials and standard clamps during the maintenance of common property in the apartment building. In rare cases, it can be replaced during ongoing repairs. separate plot(sections) of a pipeline on which several drip leaks have formed. These defects do not disrupt the operation of the entire heating system and do not lead to emergency situations.
When polymer pipes are used for a long time as a coolant under the influence of pressure and mainly temperature, they lose their ability to resist and are destroyed.
The cause of destruction of metal-plastic and polypropylene pipes with aluminum reinforcement can also be defects in the manufacture of pipes and poor-quality installation.
During the manufacturing process of pipes, defective aluminum tape may be used or the technological requirements for its installation may be violated.
During installation, the ends of the pipe may not be trimmed before resistance welding. In this case, the coolant under pressure penetrates into the space formed between the layer of aluminum tape and the top layer of polypropylene, which leads to swelling of this layer, leakage of the coolant and destruction of the pipe.
The main danger when using polymer pipes is the absence of signs that foreshadow the destruction of the pipes and the scale of the most possible destruction, which can immediately cover the entire house or several floors into which coolant flows with more high temperature. Therefore, you should strictly observe the service life established for polymer pipes in the heating system and replace them in a timely manner.
It is obvious that the reliability of heating systems during modernization is ensured by the fulfillment of a number of conditions that require certain material costs.
It should also be taken into account that the documents of the Fund for Assistance to the Reform of Housing and Public Utilities recommend the use of polymer pipes only in water supply systems.
When assessing the feasibility of upgrading a heating system, the social aspect should be taken into account.
Modernization can prevent flooding in apartment buildings. But it does not occur during normal operation of the heating system, and its value will be significantly reduced by shut-off and control valves and heating devices. Modernization will somewhat improve the operation of the heating system and comfortable temperature conditions in residential premises. But operating costs will increase.
EXAMPLE
The capital costs of replacing an elevator unit with an automated one for a 70-apartment building are comparable to the cost of replacing all heating system pipelines in this building or replacing all heating devices with aluminum radiators.
4 CONCLUSIONS
1. The inclusion of work on the modernization of heating systems with elevator units in the KR MKD program is not economically feasible.
2. Replacement of control valves in heating systems is necessary.
3. Modernization of the hot water supply system is timely and must be carried out in accordance with the requirements of the Federal Law “On Heat Supply”.
4. Modernization of engineering systems is not included in the list of works for the Kyrgyz Republic presented in Part 1 of Art. 166, Housing Code of the Russian Federation. Their inclusion in this list in accordance with Part 2 of Art. 166 of the Housing Code of the Russian Federation must be sanctioned by the normative legal act subject of the Russian Federation.
Hello, dear Reader!
I want to tell you about what heating systems I have encountered.
Some he operated, some he assembled himself, including heating systems for private houses.
I learned a lot about their pros and cons, although probably not everything. As a result, for my home I made:
- firstly, your own scheme;
- secondly, it is quite reliable;
- thirdly, allowing modernization.
I suggest not going into detailed study various schemes heating.
Let's look at them from the point of view of application in a private home.
After all, a private house can be for permanent residence, or temporary, like a summer house, for example.
So to speak, let’s narrow our topic and get closer to practice.
I was probably wrong about ten years. I started servicing my first heating system 33 years ago, when I was a student at the Ural Polytechnic Institute. I was lucky to get a job in the boiler room of the institute as a mechanic on duty. True, then I didn’t even think about what it was like, this system? It worked and that's it.
The work was sometimes difficult, when there was some kind of accident. And if everything is fine - beautiful, sit and study your notes. I spent the night on duty, in the morning I went to school, “to school,” as we used to say then. Two nights later, back on duty. And most importantly, they paid 110 - 120 rubles! At that time, young specialists received the same amount. Yes, plus a scholarship of 40 rubles. Gorgeous life! But let's get closer to the warmth.
From the name itself it is clear that heating occurs with heated air. The air is heated by a heat generator and then enters the premises through air ducts. Through the return channels, the cooled air is returned to be heated. Quite a comfortable system.
The first heat generator in history was a furnace. It heated the air, which dispersed through the channels in the order of natural circulation. Such a system air heating used in past centuries in advanced urban homes.
Nowadays, a variety of heat generators-boilers are used: gas, solid fuel, diesel, electric. In addition to natural circulation, forced circulation is also used. It is, of course, more effective:
- Firstly, it warms up rooms much faster;
- Secondly, it has a higher efficiency, since heat is removed from the heat generator much more efficiently;
- Thirdly, it can be combined with an air conditioning system.
You probably already realized that there is no smell of a private home here. Yes, that’s right, for a private home this heating scheme is too cumbersome and expensive. The calculations alone are worth it, but if you make a mistake, it will be, as they say, fatal.
But let's not get upset. If you still want to warm yourself with air, there is a way out. This is a fireplace.
Moreover, in my opinion, it is not an ordinary wood-eating fireplace, but the cast-iron fireplace insert shown in the figure above. This is an ideal option for a cozy wood-burning heat generator. It is designed specifically for heating air, and not brick, like a traditional fireplace.
The air enters the fireplace space (where the firewood is stored for decoration) and flows around its heated body. Then it flows around the hot chimney along the fireplace box and exits through the holes in the upper part of the box. By the way, air ducts can be connected to these holes and distribute hot air throughout the rooms.
It’s quite a worthy option, but if you do it with air ducts, then during construction you need to remember to put them in the walls and ceilings. Some people also install an inflator, creating forced ventilation. But this, in my opinion, is already too much. By the fireplace it is pleasant to listen to the crackling of the wood rather than the noise of the fan.
I think it’s worth mentioning also fan heaters and heat guns. These are, so to speak, mobile air heating units. Very useful devices, especially when the main heating system is not working or you need to quickly “heat up” the air in the room. But, in my opinion, they cannot be considered as the main heating option.
So, a fireplace insert as a source of air heating is a good and, moreover, pleasant solution for a private home.
Water heating at home
In this case, the coolant is water or special liquids, for example, antifreeze. Here the heat sources are also very different depending on the fuel. But if in the air system warm air comes into the room, then into the water air of the room heated by appliances who give it to him heat accumulated in water.
And water accumulates a lot of heat. There is such a concept: “heat capacity”, remember? If in your own words,
The heat capacity of water is the amount of heat that must be transferred to water in order for its temperature to rise by one degree.
So this indicator for water is very good. Look at the table on the right.
It turns out that we get a luxurious coolant for practically nothing.
Yes, the water system is somewhat more complicated, but it is also more flexible.
Imagine, heated water can be supplied through pipes anywhere and there it will release the accumulated heat.
And the pipes can be easily hidden in the walls, or not hidden at all; modern ones look very aesthetically pleasing.
How does water give off heat? Several types of devices have been created for this:
- Radiators are massive, for example cast iron, sections assembled into batteries.
Hot water flows inside them. They release thermal energy mainly due to infrared radiation(radiation).
They are usually steel or aluminum, less often copper. Ambient air, heating up from the convector, begins a natural upward movement. That is, a flow (convection) of air is created that removes heat from the convector.
Modern aluminum appliances also belong to convectors, although they are called radiators. It should be noted that now almost everything thermal appliances water heating is called radiators, although strictly speaking this is incorrect. But let's not be clever.
Air is pumped through them to be heated. Often used in systems supply ventilation to heat the cold air coming in from outside.
- “Warm walls” - used in the seventies in panel housing construction. A coil of steel pipe was embedded in the concrete panels, into which water was supplied from the heating system. I remember from childhood warm walls panel five-story buildings.
The water system can be successfully used in a private home. If this is a dacha, you can fill in non-freezing coolant instead of water and not worry about defrosting the system.
Let's take a closer look at the options for heating systems for low-rise buildings.
Scheme of a gravity heating system
Why gravity? Because the water in it actually flows by itself. When heated in the boiler, the water rises, and then, gradually cooling in the radiators, flows down and returns to the boiler again. The system is simple, but the mandatory conditions must be met:
- The pipe should be pretty large diameter from 50 mm, and preferably 76 mm and more.
- The pipe is laid with a slope to ensure gravity flow of water.
Sometimes this very pipe heats a room without radiators and convectors due to its large mass and surfaces. Such pipes are called registers, they can be found at train stations and bus stations in old small cities. It is now rarely used in private homes - it does not look very aesthetically pleasing. Imagine - there is a thick pipe in the room, and even an inclined one.
Very great dignity This system does not require a circulation pump, the water circulates itself. If the boiler is wood, coal or gas, no power outages are a problem, complete autonomy and independence. I’m talking about this because I myself have problems with power outages.
A feature of the gravity system, which is considered a disadvantage, is that it is open, that is, it communicates with air and there is no pressure in it. This means that you need an open expansion tank and the water gradually evaporates, you need to monitor this. Of course, this is not a very serious drawback. I'm more put off by the high sloping pipes.
For a private house, a closed heating system, in my opinion, best option. It would be better to say closed. Closed means not having contact with air. New elements appear here:
- Diaphragm expansion tank to compensate for the expansion of water when heated;
- Circulation pump for pumping water through the system;
- Safety group - make-up valve (for adding water to the system in case of leakage), pressure gauge, safety valve (for releasing steam when water boils).
This is a more modern, aesthetic option. Radiators are used here, and more often aluminum convectors, thin metal-plastic or polypropylene pipes. There is no need to add water or think about tilting the pipes; they can be hidden in walls or ceilings.
You can supply beautiful aluminum or bimetallic radiators, heated towel rail. I use two boilers in one system - an electric boiler and a water circuit for the fireplace insert. Looks like it worked out well.
The disadvantage of the system is that there is no electricity for circulation pump she won't be able to work. Moreover, if the firebox is “steamy” and the electricity has run out, it can result in a “boom” with the release of steam and a lot of noise. I know it from myself. It feels like someone is hitting the pipes with a hammer.
Therefore, the pump was connected to an uninterrupted source (like a computer) so that there was time to safely cool the firebox. And also a way out safety valve- into the sewer.
Two-pipe heating system
There are two options for connecting radiators to the heating system:
The only plus single pipe system– savings on pipes. But there is a significant minus - the radiator closest to the boiler is the hottest, and the farthest is the coldest. It is also problematic to turn off a radiator - they are all in the same circuit. If it's not critical, why not use this option? Quite a normal scheme.
The two-pipe scheme is more flexible:
- All radiators are in almost equal conditions. Water is supplied to each person at the same temperature;
- You can set your own temperature on each radiator by regulating the flow of water through it;
- You can safely shut off the water supply to any radiator, for example, when it is hot or you need to flush the radiator;
- More convenient for increasing the number of radiators.
Thus, in my opinion, the two-pipe scheme is more preferable.
For the sake of fairness, it must be said that in the two-pipe version, the last radiator is somewhat “offended”; it receives less heat. The reason is that the pressure difference between the supply and return is practically zero and the water flow is minimal.
So what choice did I make?
In my house I installed air-water system heating. The fireplace is responsible for the air supply. Closed two-pipe water diagram includes an electric boiler, a water circuit for the fireplace insert and 40 aluminum radiator sections (6 radiators). 64 square meters of the first floor are heated in excess in any frost.
That's all for today. In the following articles I will bring to your attention the system gas heating, warm floor, infrared heating. Comment, ask questions. Thanks, see you!