weather regulation. Typical heating control schemes
Weather-dependent automation with a mixing three-way cock (valve) and a circulation pump. In this article, we continue the analysis of possible options for schematic solutions for the implementation of the device weather-compensated automation in an individual heating point (ITP) or frame management of multi-storey residential buildings. This time we have a diagram of weather-dependent automation with a three-way mixing valve (valve) and a circulation pump.
In this scheme, regulation temperature in the heating system is due to changes (limitations) of coolant flow through a three-way valve and at the same time the intake (admixture) returned from the heating system of a residential building network water using a network or as it is also called circulation pump and supplying already diluted water again to the heating system of apartments. There are three main elements in this scheme - three-way valve, pump and controller - computer. It is the controller that constantly, at certain intervals, interrogates the temperature sensors of the coolant, outdoor air and air inside the apartments of a residential building (if any), processes the received information and, in accordance with the program entered into it (in this case, the temperature graph) generates a signal that gives the command mechanism three-way valve for opening or closing.
This influence of the controller corrects the amount of opening or closing of the flow section of the control valve. If this weather-compensated control system does not have an air sensor inside the apartments, then the weather regulation is carried out in accordance with the temperature schedule.
And, finally, the last type of automation for maintaining the temperature in apartments of residential buildings, depending on the temperature outside, is weather-dependent automation with a shut-off control valve and a circulation pump.
Let us analyze the principle of operation of this automation of maintaining the temperature in the apartment, or rather, in the entire multi-apartment residential building.
Here, the temperature in the heating system is controlled by changing bandwidth valve and, as in the previous scheme for mixing return (return) network water from a residential building using a circulation pump, now installed on the return pipeline heating system. It is important where the network or circulation pump, in general, it doesn’t matter, it’s just that for a two-way valve such a scheme is still preferable because of its design features.
In the process of regulation, the controller also periodically interrogates the temperature sensors of the coolant in the heating system of the house, the room air sensors (if installed) and the outdoor air sensor. After processing the received information, the controller generates an output control signal to open or close the actuator of the two-way valve, while the value of opening or closing of the flow area of the control valve changes accordingly. With absence indoor air sensor The main priority of regulation is also maintaining the temperature in the apartments according to the temperature schedule.
There is only one drawback of control schemes with valves - the loss of electricity, for more information about the advantages and disadvantages of weather-dependent automatics, see the article.
The advantage of weather control schemes with valves
before the regulating elevator, the depth of regulation is usually called, although in our opinion such an advantage is controversial and can easily turn into a disadvantage if, for example, there is a thermal energy metering unit in the ITP, and its measurement limits are worse than the limits of the weather control automatics. After installing automatic weather control without coordination with the energy supply organization, such a UUTE can legally be recognized as non-commercial, which means that instead of saving you will again receive.
Weather-compensated control schemes with valves should be used in those ITP residential buildings where it is technologically impossible to use elevators, and this:
- insufficient pressure at the inlet to the ITP, less than 0.07 MPa
- overestimated resistance internal system home heating, more than 5 m.
- installation on heating devices and risers of automatic control valves, for example, Danfoss
- usage independent system heating through heat exchangers.
I would also like to warn residents, especially weather-dependent automation schemes with mixing valves cannot be used without pump or with pump turned off . In the mode of operation with the pump turned off, the pumping of the coolant through the heating devices decreases sharply, the difference in temperatures between the temperatures in the heating devices different apartments sometimes it reaches 45 degrees, instead of twelve recommended for the economical mode of operation of weather-dependent automation. And most importantly, due to the lack of mixing in frosts, the temperature in the heating devices of the first apartments along the way can reach 115 degrees or more, which will inevitably lead to the failure of modern polypropylene pipes , as well as burns when accidentally touching heating devices - this is at least. At the same time, the residents of the last apartments along the coolant will sit in the cold.
This is such a savings, and according to the instruments everything will be OK. And most importantly, if the check valve on the jumper between the direct and return pipeline fails, not only your house, but the entire area may be left without heat. The coolant will not go to the apartments, but will return back to the boiler room.
We dismantled possible options schematic solutions for the implementation of weather-dependent automation in the control frame of multi-storey residential buildings. In any case, the decision to choose one or another scheme of weather-dependent temperature control in the apartments of a residential building, and most importantly, the selection of equipment should be entrusted to specialists. You, as residents, should only say your word when choosing a design organization and the type of equipment - domestic or imported. it depends on that.
Everything purchased and installation and adjustment of automatic weather control in apartments of residential buildings on the next page.
The problem of the efficiency of the heating system in most cases is the choice of the optimal correspondence between the temperature outside and the current heat consumption of the building. Very often, boiler houses (this is due to the specifics of the operation of power equipment) do not have time to respond to rapid changes in weather conditions. And then we can see the following picture: it's warm outside, and the radiators are burning like crazy. At this time, the heat meter winds up round sums for heat that no one needs.
Solve the problem of rapid response an automatic weather-based heat consumption control system will help to detect changes in weather conditions in a single building. The essence of this system is as follows: an electric thermometer is installed on the street, measuring the air temperature in this moment. Every second, its signal is compared with a signal about the temperature of the coolant at the outlet of the building (that is, in fact, with the temperature of the coldest radiator in the building) and / or with a signal about the temperature in one of the premises of the building. Based on this comparison, the control unit automatically commands the electric control valve, which sets optimal value coolant consumption.
In addition, such a system is equipped with a timer for switching the operating mode of the heating system. This means that when a certain hour of the day and (or) day of the week comes, it automatically switches the heating from normal to economical mode and vice versa. The specifics of some organizations do not require comfortable heating at night and the system at a given hour of the day will automatically reduce the heat load on the building by a given value, and therefore save heat and money. In the morning, before the start of the working day, the system will automatically switch to normal operation and warm up the building. The experience of installing such systems shows that the amount of heat savings obtained from the operation of such a system is about 15% in winter and 60-70% in autumn and spring due to constant periodic warming.
Today one of the most effective ways energy saving is the saving of thermal energy at the objects of its final consumption: in heated buildings. The main condition that ensures the possibility of such savings is, first of all, the obligatory equipping of heat points with heat meters, the so-called. heat meters. The presence of such a device allows you to quickly recoup capital investments in equipment heating systems energy-saving equipment and in the future receive significant savings in financial costs that usually go to pay the bills of energy companies.
Heat meters. The simplest heat meter today is a device that measures the temperature and flow rate of the coolant at the inlet and outlet of the heat supply facility (see Fig.).
Graph 3. Heat calculator operation
According to the information from the sensors, the microprocessor heat calculator determines the heat consumption for the building every moment and integrates it over time.
Technically, heat meters differ from each other in the method of measuring the flow rate of the coolant. To date, commercially available heat meters use the following types of flow meters:
- · Heat meters with variable pressure drop meters. Currently this method very outdated and rarely used.
- · Heat meters with vane (turbine) flow meters. They are the cheapest devices for measuring heat consumption, but have a number of characteristic disadvantages.
- · Heat meters with ultrasonic flowmeters. One of the most progressive, accurate and reliable heat meters today.
- · Heat meters with electromagnetic flowmeters. In terms of quality, they are approximately on the same level as ultrasonic ones. All heat meters use standard resistance thermometers as temperature sensors.
Chart 4. One of standard options single-circuit installation automatic system regulation of heat consumption by the building with correction according to weather conditions
The actual standard of any building heating system "in the west" today is the mandatory presence in it of the so-called. automatic heat load control system with weather correction. The most typical scheme of its layout is shown in fig. 3.
Signals about temperatures in the control room and the heating medium supply pipeline are corrective. Another control option is also possible, when the controller will maintain the temperature set according to the schedule in the control room. Such a device is usually equipped with a real-time timer (clock) that takes into account the time of day and switches the building's energy consumption mode from “comfortable” to “economical” and back to “comfortable”. This is especially true, for example, for organizations in which there is no need to maintain a comfortable heating regime in the premises at night or on weekends. The system also has the functions of limiting the value of the maintained temperature according to the upper or lower limit and frost protection.
Graph 5. Scheme of circulation of flows inside the building in conventional systems heat supply
Strange as it may seem, but for some reason at the time Soviet Union in the projects of almost all newly built high-rise buildings, one of the most non-optimal schemes of piping of heating systems was laid in terms of heat distribution, namely, vertical. The presence of such a wiring diagram in itself implies a temperature imbalance on the floors of the building.
Graph 6. Scheme of circulation of flows inside the building in closed loop flows
An example of such a skew ( vertical wiring) is shown in the figure. The direct coolant from the boiler room rises through the supply pipeline to the top floor of the building and from there slowly descends down the risers through the radiators of the heating system, collecting at the bottom into the return pipeline collector. Due to the low flow rate of the coolant through the risers, a temperature imbalance occurs - all the heat is transferred to upper floors and hot water simply does not have time to reach the lower floors, cooling down along the way.
As a result, it is very hot on the upper floors, and people who are there are forced to open the windows through which the very heat that is lacking on the lower floors comes out.
The presence in the building of such a temperature imbalance implies:
Lack of comfort in the premises of the building;
Constant loss of 10-15% of heat (through the windows);
Impossibility of saving heat: any attempt to reduce the heat load will further aggravate the situation with temperature imbalance (because the coolant flow rate through the radiators will become even lower).
To solve a similar problem today, you can only use:
- Complete redesign of the entire heating system of the building, which, by the way, is a very time-consuming and expensive pleasure;
- installation of a circulation pump in the elevator, which will increase the rate of circulation of the coolant through the building.
Similar systems are widespread in the "west". The results of experiments carried out by Western colleagues exceeded all expectations: in the autumn and spring periods, due to frequent temporary warming, the heat consumption at the facilities equipped with these systems amounted to only 40-50%. That is, heat savings at that time amounted to about 50-60%. In winter, the decrease in load was much less: it reached 7-15% and was obtained mainly due to the automatic “night” decrease in temperature in the return pipeline by 3-5 °C by the device. In general, the total average heat savings for the entire heating period, at each of the objects, amounted to about 30-35% compared to last year's consumption. Payback period installed equipment amounted (depending, of course, on the thermal load of the building) from 1 to 5 months.
Scheme 7. circulation pump
The most impressive results from the introduction were achieved in the city of Ilyichevsk, where in 1998 24 central heating centers of OAO Ilyichevskteplokommunenergo (ITKE) were equipped with similar systems. Only thanks to this, ITKE was able to reduce gas consumption in its boiler houses by 30% compared to the previous one. heating period and at the same time significantly reduce the operating time of their network pumps, since the regulators contributed significantly to equalizing hydraulic mode heating networks over time.
The hardware implementation of such a system may be different. Both domestic and imported equipment can be used.
An important element in this scheme is the circulation pump. The noiseless, foundationless circulation pump performs the following function: increasing the speed of the coolant flowing through the radiators of the building. To do this, a jumper is installed between the supply and return pipelines, through which a part of the return heat carrier is mixed into the direct one. The same coolant passes quickly and several times along the inner contour of the building. Due to this, the temperature in the supply pipeline drops, and due to the increase in the speed of the coolant flow through the internal contour of the building several times, the temperature in the return pipeline rises. There is an even distribution of heat throughout the building.
The pump is equipped with all necessary safety devices and operates fully automatically.
Its presence is necessary for the following reasons: firstly, it increases the circulation rate of the coolant several times along the internal contour of the heating system, which increases comfort in the building. And secondly, it is necessary because the regulation of the heat load is carried out by reducing the flow rate of the coolant. In the case of a single-pipe wiring of the heating system in the building (and this is the standard of domestic systems), this will automatically increase the temperature imbalance in the rooms: due to a decrease in the flow rate of the coolant, almost all heat will be given off in the first radiators along its course, which will significantly worsen the situation with heat distribution in the building and reduce the efficiency of regulation.
It is difficult to overestimate the prospect of introducing such equipment. This is effective remedy solving the problem of energy saving at the facilities of the end consumer of heat, which is capable of giving such a high economic effect at such relatively low costs.
In addition, there are various methods optimization and the choice of one or another is determined by a specialist based on the specifics of the object.
In accordance with the requirements of regulatory documentation and Federal Law No. 261 "On Energy Saving ..." should become the norm, both for new construction facilities and for existing buildings, as it is the main tool for managing heat supply. Today, such systems, contrary to popular belief, are quite affordable for most consumers. They are functional, high reliability and allow you to optimize the process of consumption of thermal energy. The payback period for the installation of equipment is within one year.
System automatic regulation heat consumption () allows you to reduce the consumption of thermal energy due to the following factors:
- Elimination of excess thermal energy (overheating) entering the building;
- Decrease in air temperature at night;
- Decrease in air temperature during the holidays.
Aggregated indicators of thermal energy savings from the use of ACS installed in an individual heating point () of the building are shown in Fig. No. 1.
Fig.1 Total savings reach 27% or more*
*according to LLC NPP Elekom
The main elements of classical SART in general view shown in fig. No. 2.
Fig.2 Main elements of SART in ITP*
*auxiliary elements are conditionally not shown
Purpose of the weather controller:
- Temperature measurement of outdoor air and coolant;
- KZR valve control, depending on the established control programs (schedules);
- Data exchange with the server.
Purpose of the mixing pump:
- Ensuring a constant flow of coolant in the heating system;
- Providing a variable admixture of the coolant.
Purpose of the KZR valve: control of the flow of coolant from the heating network.
Appointment of temperature sensors: measurement of temperatures of the heat carrier and external air.
Additional options:
- Differential pressure regulator. The regulator is designed to maintain a constant pressure drop of the coolant and eliminates the negative impact of the unstable pressure drop of the heating network on the operation of the ACS. The absence of a differential pressure regulator can lead to unstable system operation, reduced economic effect and reduced equipment life.
- Room temperature sensor. The sensor is designed to control the indoor air temperature.
- Data collection and management server. The server is designed for remote monitoring of equipment performance and correction heating schedules according to the readings of the indoor air temperature sensors.
Principle of operation classical scheme SART consists of qualitative regulation supplemented by quantitative regulation. Quality regulation- this is the change in the temperature of the coolant entering the heating system of the building, and quantitative regulation is the change in the amount of coolant coming from the heating network. This process occurs in such a way that the amount of coolant supplied from the heating network changes, and the amount of coolant circulating in the heating system remains constant. Thus, the hydraulic mode of the heating system of the building is preserved and the temperature of the coolant entering the heating devices changes. Keeping the hydraulic regime constant is necessary condition for uniform heating of the building and effective work heating systems.
Physically, the regulation process takes place as follows: the weather controller, in accordance with the individual control programs embedded in it and depending on the current temperatures of the outdoor air and coolant, supplies control actions to the KZR valve. When set in motion, the shut-off body of the KZR valve reduces or increases the flow of network water from the heating network through the supply pipeline to the mixing unit. At the same time, due to the pump in the mixing unit, a proportional selection of the coolant from the return pipeline and mixing it into the supply pipeline is carried out, which, while maintaining the hydraulics of the heating system (the amount of coolant in the heating system), leads to the required changes in the temperature of the coolant entering the heating radiators. The process of lowering the temperature of the incoming coolant reduces the amount of thermal energy that is taken per unit time from heating radiators, which leads to savings.
SART schemes in ITP buildings from different manufacturers may differ slightly, but in all schemes the main elements are: weather controller, pump, KZR valve, temperature sensors.
It should be noted that in the context of the economic crisis, all large quantity potential customers become price sensitive. Consumers start looking alternative options with the lowest equipment composition and cost. Sometimes along this path there is an erroneous desire to save on the installation of a mixing pump. This approach is not justified for SART, installed in ITP buildings.
What happens if the pump is not installed? And the following will happen: as a result of the operation of the KZR valve, the hydraulic pressure drop and, accordingly, the amount of coolant in the heating system will constantly change, which will inevitably lead to uneven heating of the building, inefficient operation heating appliances and the risk of stopping the circulation of the coolant. In addition, at negative outdoor temperatures, “defrosting” of the heating system may occur.
Saving on the quality of the weather controller is also not worth it, because. modern controllers allow you to choose a valve control schedule that, while maintaining comfortable conditions inside the facility, allows you to get significant amounts of savings in thermal energy. This includes such effective programs heat consumption management as: elimination of overheating; reduced consumption at night and non-working days; elimination of overestimation of return water temperature; protection against “defrosting” of the heating system; correction of heating curves according to the air temperature in the room.
Summing up what has been said, I would like to note the importance professional approach to the choice of equipment for the system of weather automatic control of heat consumption in the IHS of the building and emphasize once again that the minimum sufficient basic elements of such a system are: a pump, a valve, a weather controller and temperature sensors.
23 years of work experience, ISO 9001 quality system, licenses and certificates for the production and repair of measuring instruments, SRO approvals (design, installation, energy audit), accreditation certificate in the field of ensuring the uniformity of measurements and recommendations from customers, including government bodies, municipal administrations, large industrial enterprises, allow the ELECOM enterprise to implement high-tech solutions for energy saving and energy efficiency with an optimal price / quality ratio.
Currently, the share of payment for HEATING, the largest line in the receipt for communal payments. In this regard, many owners are interested in the possibility of reducing these costs.
One way to do this is to equip the home heating system with an automatic ITP (weather regulator).
The system of weather regulation of heating justifies itself only if a heat meter (heat energy metering unit) is already installed in the house.
It is difficult for power engineers to comply with the temperature schedule (temperatures on the heating supply and return pipelines depending on the temperature of the outside air). Their goal is to give as much as possible more heat for consumers, in order to have enough temperature for all houses located in the area around the central heating station (nearest, and remote). Also, at the central heating station, the parameters of the coolant do not change in reciprocity with the time of day (sunny day, night, day of the week, etc.)
Automatic heat control system
After equipping with automatic ITP, each house will be able to individually regulate the parameters of the coolant of the internal heating circuit (battery temperature), according to the specified parameters, depending on the external temperature. It is also constantly at a sufficient level to maintain the circulation of the coolant inside the house, during a low pressure drop provided by power engineers. (Example: Autumn 2013, complaints about cold batteries due to a difference of less than 1 m between supply and return at ITP elevators).
Automatic ITP allows you to save up to 35% (or more) Gcal, and hence money. Considering that apartment house pay for heating heating season several million rubles, then saving even 25% pays for the entire system from one season! And with an increase in the tariff (price per Gcal), the payback time decreases.
The principle of operation of automation
Automatic ITP (Weather Control Unit) consists of a control valve with an electric drive, a circulation pump, check valve, temperature sensors, electrical cabinet controls (with a software controller), shut-off and control valves, filters, etc. The characteristics of the components for the weather regulator are selected by an experienced designer based on a specific object. Here are taken into account thermal loads, flow rate, hydraulic resistance, differential and much more.
Our company has extensive experience in the design, installation and commissioning of these devices.
The weather control system works in the following way. Outside air sensor (output to shady side street) measures the outside temperature. Two sensors on the supply and return pipes measure the temperature of the heating system. The programmable logic controller calculates the required delta and controls the flow rate of the coolant by controlling the valve. If the heating network does not have the required differential, then the problem is eliminated by installing an automatic balancing valve.