RU2473014C1 - Control method of single-pipe heat supply system - Google Patents

Abstract

FIELD: heating.

SUBSTANCE: method relates to control of heat carrier temperature in response to changes of external parameters (temperature) and flow rate in response to changes of heat carrier temperature in return pipeline. Control method of the system containing the set of heat exchange units (6) connected in series so that return pipeline (4) of one heat exchange unit (6) is supply pipeline (3) of the next heat exchange unit (6); main supply line (1) connected to supply pipeline (3) of the first one if to look in the flow direction from heat exchange units (6); main return pipeline (2) connected to return pipeline (3) of the last one (if to look in the flow direction) from heat exchange units (6); at which the heat carrier with supply temperature is supplied with certain flow rate from main supply pipeline (1) to the set of heat exchange units (6); in which the supply temperature is controlled in compliance with the supply temperature set point depending on parameters that are external in relation to system of parameters, and flow rate is controlled in compliance with the temperature set point in return pipeline depending on downstream heat carrier temperature from the first unit (6) of the set of heat exchange units.

EFFECT: improvement of the system control is provided.

17 cl, 7 dwg

Description

A method of controlling the flow and supply of coolant to the riser of a one-pipe system of a typical layout, for example, for building cooperatives, for supplying heat to radiators in apartments. This method relates to controlling the temperature of the coolant in response to changes in external parameters (temperature) and flow rate response to changes in the temperature of the coolant in the return pipe.

BACKGROUND

Pipeworked radiators, for example, in buildings or building cooperatives, are usually assembled either as a two-pipe or as a single-pipe system. Below we will talk, in general, about "houses", referring to buildings consisting of several apartments, or any other premises for which such layouts are typical.

In traditional two-pipe systems, a set of parallel pipes forms supply pipelines (or, using the more general term, “lines”) for a set of heat exchangers, for example radiators. Pipelines connected to each such set of heat exchangers are called risers; in traditional two-pipe systems, the flow rate in each riser is regulated separately, thus, according to the current load, the dynamic flow rate in each riser.

However, in single-pipe systems, a coolant (usually water) with a certain flow rate and a certain temperature of the medium (usually water) is supplied through a supply pipe to a set of heat exchangers. The individual radiators are connected in series, one after the other, so that the return pipe of one radiator is the supply pipe for the next radiator.

Typically, the flow rate of the coolant for each radiator is controlled using thermostats installed by users of the radiators, but in traditional systems the total flow rate in the supply pipe and return pipe is essentially constant, that is, it does not change depending on load changes.

For example, on a hot day, or simply when an increase in room temperature causes the radiator thermostat to close, the radiator thermostats generally shut down so that most of the coolant flows through the bypass. This arrangement leads to an undesirable high temperature of the coolant in the return pipe (return pipes). High temperature of the coolant is undesirable, as this leads to uncontrolled heating of residential premises and, moreover, excessive loss of heat of the coolant in the pipelines, since the pipelines continue to supply heat, although the radiators are closed. In particular, this is the case if the pipelines are poorly insulated. This causes tenants additional inconvenience.

In two-pipe systems, a flow control valve is centrally located. In the case of a single-tube system, this is not possible, since this would lead to insufficient flow in parts of the system that still have a large load, and to excessive flow in parts / risers with low load.

This invention relates to the use of a solution that allows you to create a highly efficient single-tube system with load-dependent energy consumption.

SUMMARY OF THE INVENTION

In this invention, the problem of single-pipe systems is solved through the use of double regulation: one for regulating the temperature of the supplied coolant, that is, the supply temperature, and another for regulating the flow rate through the set of heat exchangers depending on the temperature of the coolant in the return pipe. The regulation of flow and temperature in the return pipe of each riser is carried out "decentralized".

The control of the supply temperature is based on external conditions, including conditions affecting the system that the system itself cannot influence, for example, when using a weather controller, these conditions preferably include weather (in particular, outdoor temperature, for example, the outdoor temperature in the area of the building) but these conditions may also include other factors that may affect the estimated amount of heat that needs to be supplied to the house. The main, but not exclusive embodiment of the invention is particularly related to the outside temperature, therefore, the system optionally comprises an outside temperature sensor. In an even more preferred embodiment, the system is connected to a weather forecast system, for example, via the Internet.

Thus, the present invention provides a method for regulating a system that comprises:

a set of heat exchangers connected in series, so that the return pipe of one radiator is a supply pipe for the next radiator;

the main supply pipe connected to the supply pipe of the first (when viewed in the direction of flow) from the heat exchangers;

the main return pipe connected to the return pipe of the latter (when viewed in the direction of flow) from heat exchangers;

in which the coolant with the supply temperature is supplied with a certain flow rate from the main supply pipe to the set of heat exchangers,

at which the supply temperature is controlled in accordance with the setpoint for the supply temperature depending on the parameters external to the system, and the flow rate is controlled in accordance with the setpoint for the return temperature depending on the temperature of the coolant downstream relative to the first set of heat exchangers.

In order to ensure the optimal setpoint of the system, in one embodiment of the invention, the supply temperature is controlled in accordance with the setpoint of the supply temperature depending on the parameters external to the system, and / or the flow rate is controlled in accordance with the setpoint of the return temperature depending on the temperature of the coolant down downstream relative to the first heat exchanger in the aggregate. The return temperature setpoint is preferably controlled in response to the adjustment of the supply temperature setpoint.

In order for the system to have means for performing flow control depending on the temperature of the coolant in the return pipe, with the proposed method in accordance with an additional embodiment of the invention, in addition, a system is used, further comprising:

a flow regulator connected to the return pipe, and the flow controller is adapted to control the flow in the return pipe;

an actuator controlling the flow regulator;

temperature sensor located in heat exchange connection with the coolant in the return pipe.

In order to ensure continuous flow, despite frequent changes in the load of each of the heat exchangers, for example, when these devices are controlled by users, the flow regulator is also configured to maintain a constant flow despite pressure changes in the main supply pipe.

In order to avoid supplying too much energy to the system, preferably by meeting environmental conditions well in advance, in one embodiment of the invention, the system may comprise an external temperature sensor configured to measure an external temperature to the system.

In particular, but not exclusively, to provide temperature control in the return pipe according to the set point depending on various parameters, in one embodiment of the invention, the system may include an electronic controller connected to actuators and temperature sensors connected to the return pipes. Optionally, an electronic controller is connected to a temperature sensor connected to the main supply pipe, and also optionally to an outside temperature sensor.

In one embodiment of the invention, the actuator is controlled by pulses, for example, in cases where the actuator is an electromagnetic, pneumatic, hydraulic or electrostrictive control device.

In order to ensure an optimal setpoint of the system, in one embodiment of the invention, the flow temperature is controlled in accordance with the set flow temperature depending on the parameters external to the system, and the flow rate is controlled in accordance with the return temperature setpoint depending on the temperature of the coolant downstream relative to the first of the set of heat exchangers. The return temperature setpoint is preferably controlled in response to the adjustment of the supply temperature setpoint.

In an alternative embodiment with an electronic controller, actuators are connected directly to temperature sensors, these devices are autonomous devices and contain means for regulating the temperature setpoint in the return pipe. The natural choice is that the actuator is a thermostat.

BLUEPRINTS

Figure 1. The standard layout of a single pipe system in which this invention can be used.

Figure 2. Several parallel risers, each of which is combined with a set of heat exchangers, each riser being adjusted in accordance with one embodiment of the present invention.

Figure 3. A flow regulator used in one embodiment of the invention, the regulator being adapted to maintain a constant flow rate despite pressure changes.

Figure 4. Graphs of the setpoint versus outdoor conditions.

5A and 5B. Graphs showing how this invention allows to establish a ratio with the flow rate to better match the actual load in the system.

6. A system in which an electronic controller is used in accordance with one embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Figure 1 shows a typical single-tube system configuration in which a certain amount of coolant (usually water) having a supply temperature is supplied through a supply pipe 3 to a set of heat exchangers 6, for example radiators, with a certain flow rate, and which is adapted for heating several residential premises . Below, without loss of generality, such heat exchangers 6 are often called radiators. The individual radiators 6 are connected in series, one after the other, so that the return pipe 4 of one radiator 6 is the supply pipe 3 for the next radiator 6. The supply pipe 3 and the return pipe 4 of each radiator 6 are additionally connected bypass 5. The main supply pipe 1 is connected to the supply pipe 3 of the first (if you look in the direction of flow) from radiators 6, and the main return pipe 2 is connected to the return pipe 4 of the last (if you look in the direction of flow) from Ators 6 of the aggregate.

In some places, this arrangement is typical for houses containing several rooms and apartments, in which, for example, each of several parallel risers is connected to several rooms or apartments. In this text, each of the rooms or apartments is considered as one heat exchanger, in this case the rooms (apartments) associated with the riser contain a “totality” of heat exchangers or radiators 6.

Separate radiators 6 inside each room (apartment) can connect in accordance with a similar or very different layout.

Thus, in houses that contain several risers, such a system contains a corresponding set of radiators connected in series and connected to a common main supply pipe 1 and main return pipe 2, moreover, the flow rate in each of the sets is regulated separately.

The coolant can be supplied directly to the radiators 6 (hereinafter we will call it a direct-supply arrangement), or the substation containing a heat exchanger separating the supply pipelines, for example, from the building, can be used in the system (hereinafter we will call this the arrangement with the substation), thus forming a closed loop for the coolant circulating in individual radiators 6. The flow rate of the coolant in each radiator 6 is controlled by means of flow control 7, then without loss of universality called radiator terms article.

In addition, the flow control in the radiators 6 affects the flow in bypass 5; when the flow rate in the radiators 6 changes, respectively, the flow rate in bypasses 5 changes.

For example, on a hot day or simply when the influx of heat from sources in the room causes the radiator thermostat 7 to close, the radiator thermostats 7 are generally closed so that most of the coolant flows through bypass 5. This arrangement leads to an undesirable high temperature of the coolant in the opposite pipeline (return pipelines) 4. High temperature of the coolant in the return pipe is undesirable, as this leads to uncontrolled heating of residential premises and, moreover, excessive heat loss carrier in the pipelines as the pipelines continue to supply heat, although the radiators are closed. In particular, this is the case if the pipelines are poorly insulated. This causes tenants additional inconvenience.

In the present invention, this problem is solved through the use of double regulation: one to control the temperature of the supplied coolant, that is, the supply temperature, and another to control the flow rate through the set of heat exchangers 6 depending on the temperature of the coolant in the return pipe 3.

The control of the supply temperature is based on external conditions, including conditions that affect the system that the system itself cannot influence, for example, these conditions preferably include weather (in particular, outdoor temperature, for example, the temperature of the outside air in the area of the building), but these conditions may also include other factors that may affect the estimated amount of heat that needs to be supplied to homes. The main, but not exclusive embodiment of the invention, in particular, is related to the outside temperature, therefore, the system optionally comprises an outside temperature sensor 8. In an even more preferred embodiment, the system is connected to a weather forecast system, for example, via the Internet.

Thus, the regulation of flow in risers is based on actual consumption or load 2 in risers (risers), since changing consumption changes the temperature of the coolant in the return pipe (return pipes) 4.

Figure 2 shows the arrangement in accordance with this invention, in which the flow controller 9 is connected to a return pipe 4 connected to a set of radiators 6 to control the flow of coolant in the pipelines supplying these radiators 6.

In a preferred, but not restrictive embodiment, the flow controller 9 has two modes: a flow control valve and a pressure-independent balancing valve. In this embodiment, the flow controller 9 comprises means for setting a predetermined flow rate and means for providing a substantially constant flow rate despite changes in pressure in the flow system. Such valves may be commercially available, for example, the AB-QM series of products supplied by Danfoss A / S, which are disclosed, for example, in DE 10323981.

Figure 3 shows such a valve 9 or a flow regulator, consisting of two parts - a differential pressure regulator and a control valve. The differential pressure regulator maintains a constant differential pressure on the control valve 9. The control valve 9 contains a stem 31, an oil seal 32, a plastic ring 33, a cone 34 of the control valve, a membrane 35, a main spring 36, a hollow cone (pressure regulator) 37 and a vulcanized seat (regulator pressure) 38. The pressure difference ΔPcv (P2-P3) on the membrane 35 is compensated by the force of the spring 36. Whenever the differential pressure on the control valve 9 changes (due to a change in a possible pressure or control valve), the hollow cone 37 moves to a new position, which creates a new equilibrium and, therefore, keeps the differential pressure at a constant level. The control valve 9 has a linear characteristic. Its characteristic feature is the restriction of stroke, which makes it possible to adjust the Kv value. The stroke limit is changed by lifting the locking mechanism and turning the valve head 9 to the desired position. The locking mechanism automatically prevents unwanted installation changes.

The use of such a flow controller 9 gives another advantage, which consists in the fact that, for example, the flow in the risers is mutually independently controlled, despite the fact that the risers are connected to a common supply pipe (1) and a common return pipe (2).

Figure 2 shows that the flow controller is connected to the return pipe 4 of the latter (when viewed in the direction of flow) from the radiators 6, and an actuator 10 is connected to the flow controller 9, optionally using an adapter. In addition, this drawing shows a temperature sensor 11, adapted for location with heat exchange communication with the return pipe 4.

Actuators (10) can be actuators, they can be stand-alone devices or controlled devices, and they can operate according to any of the known principles, for example, electromagnetic, pneumatic, hydraulic, electroactive, etc.

So, figure 2 shows a system with double regulation: one part of the regulation relates to the regulation of the supply temperature depending on the external conditions, for example, outdoor temperature, and the second part is used to control the flow rate associated with each set of heat exchangers 6, depending on the temperature in return pipe, that is, the temperature of the coolant in the return pipe 4. Thus, this system becomes a system with variable flow and individual flow control in each standing ke, depending on the load in each of the individual risers.

Figure 4 shows two curves illustrating the regulation in accordance with this invention. The upper curve 12 is a flow temperature control curve as a function of the outside temperature. In any case, this curve shows how the setpoint for the supply temperature changes with the outdoor temperature. The exact shape of this curve and its dependence depend on several factors, for example, the state of insulation of the building; it is usually optimized in accordance with the conditions of a real system. It is preferable to change the temperature set point in the return pipe in accordance with the changes in the set temperature for the supply temperature, for example, due to problems arising from excess heat.

Similarly, the lower curve 13 is a control curve for the temperature setting in the return pipe, and this curve reflects an improved version of the main temperature control in the return pipe when the temperature set point in the return pipe is actively changed in accordance with the result of adjusting the supply temperature based on the outdoor temperature. Therefore, this curve shows the regulation of the return temperature setting. The aim of the invention is to ensure the efficiency of regulation, in which the flow rate is regulated according to the load in each riser, remained high throughout the heating season.

So, the bottom curve 13 changes due to two factors: the supply temperature and the load in the riser (risers), since the load in the risers is unpredictable and varies from 100 to 0%.

Thus, in accordance with this invention, higher order regulation is applied in the system - regulation of the supply temperature setpoint depending on the external conditions, and lower order regulation - correction of the system by changing the flow rate in accordance with the temperature in the return pipe depending on the load and riser (risers ), moreover, in embodiments of the invention, the return temperature setting is actively changed in accordance with a change in the supply temperature setting.

On figa shows a graphical representation of the dependence of flow on load in a traditional single-tube system without proposed in this invention regulation. The dashed line 14 shows the current flow rate, which fluctuates in an unpredictable way, since these systems are dynamic systems due to the operation of the radiator thermostat 7. This graph clearly shows that the wavy line 16, displaying the current load, is not in correlation with the current flow rate.

Straight line 15 is a consequence of the use in accordance with the invention, not depending on the pressure of the flow controller 9.

On figv shows the situation corresponding to this invention, when the flow rate is regulated depending on the temperature in the return pipe, thereby adjusting the flow rate in accordance with consumption or load. This gives a consumption 17, which is more consistent with current consumption, and, therefore, a more efficient system.

The system depicted in FIG. 2 corresponds to the simple configuration of the present invention, in which the actuator 10 controlling the flow rate setting of the flow controller 9 is a thermostat of any type known in the art, that is, this system is an autonomous system. The temperature sensor 11 is connected directly to the control device 10.

This arrangement has the following advantage: an additional energy source is not needed for the system to work, and each riser can be adjusted separately. The use of a conventional thermostat, known from the prior art, as an actuator 10 gives the advantage that such devices often contain means for setting a predetermined temperature, therefore, the temperature setpoint in the return pipe can be adjusted in accordance with a certain dependence, for example, shown in figure 4.

6 shows an embodiment of the invention in which all the sensors 8, 9 and 19 (a temperature sensor measuring the temperature of the coolant in the main supply pipe 1) and flow controllers 9, or alternatively actuators 10, are connected to an electronic controller 18 adapted for individual adjusting the flow rate in response to the measured temperature. The use of such an electronic controller 18 provides a number of advantages in relation to executive stand-alone devices.

The electronic controller 18 contains the necessary means for electronic controllers 18, well known in the art.

Using the electronic controller 18, the return temperature setpoint can be automatically adjusted according to the actual conditions, while in the direct control variant, the return temperature setpoint is usually set manually. This gives a huge potential for energy conservation, because in this case the system optimizes the temperature setpoint in the return pipe in accordance with the optimized curve 13 shown in Fig. 4.

In this electronic embodiment, the flow temperature is controlled by measuring the outside temperature (higher order control). Based on such control of a higher order, the temperature setpoint in the return pipe is controlled so that an appropriate value is set to optimize the performance of the system throughout the year, therefore, this characteristic does not depend on the load (outdoor temperature). The regulation of the higher order of costs in the risers is associated with individual sets of radiators 6 (loads in the risers), thus, due to this regulation, the flow rate is associated with heat consumption and, thus, transform this one-pipe system, transforming it from a regular system with a constant flow rate into a highly efficient system with variable flow.

Another advantage is that the electronic controller 18 allows you to control and record the temperature and flow rate for regulation and system control, in order to actively optimize the system parameters over time.

To protect the system pump in case of overlapping all risers, the electronic controller 18 in one embodiment of the invention can automatically open valves or flow controllers 9 located in at least one of the risers to ensure a minimum flow rate.

The presented system comprises an outside temperature sensor 8 for measuring an outside temperature. The temperature control in the main supply pipe 1 can be carried out in any way, quite understandably following from the actual layout. In the presented system with a substation, this can be done by controlling the flow rate of the coolant in the primary circuit of the substation heat exchanger 20.

The electronic controller 18 is connected to the individual actuators 10 and adapted so that it drives these devices. In one of the embodiments of the invention using the electronic controller 18, in addition, register the status of the actuators 10.

In addition, the electronic controller 18 is connected to temperature sensors 9, 19, which measure the temperature in the main supply pipe 1 and in the return pipe of the individual risers. Optionally, it can also be connected with an external temperature sender 8 (external sensor).

In one embodiment, the actuator 10 connected to the flow controller 9 is controlled by pulses. In pulse-width modulation, pulses of a certain frequency are used as a control means for precise flow control. Actuator 10 is designed to slowly close or open the flow controller 9, since this controller closes or opens for flow in the riser; the pulse causes a slight opening or closing of the actuator 9. In this case, the pulse frequency determines the open position of the flow controller 9. The higher the pulse frequency, the more open the flow controller 9 or alternatively, the less closed the controller 9. It is preferable that the pulses cause the actuator 10 to close the flow controller 9, since in the event of a system malfunction some flow will still be preserved, but the present invention is not limited to such a solution.

Claims (17)

1. A method of controlling a system comprising a plurality of heat exchangers (6) connected in series, so that the return pipe (4) of one heat exchanger (6) is a supply pipe (3) of the next heat exchanger (6); the main supply pipe (1) connected to the supply pipe (3) of the first, when viewed in the direction of flow, from heat exchangers (6); main return pipe (2) connected to the return pipe (3) of the latter (when viewed in the direction of flow) from heat exchangers (6); in which the coolant with the supply temperature is supplied with a certain flow rate from the main supply pipe (1) to the set of heat exchangers (6); in which the supply temperature is controlled in accordance with the setpoint of the supply temperature depending on the parameters external to the system, and the flow rate is controlled in accordance with the setpoint of temperature in the return pipe depending on the temperature of the coolant downstream of the first apparatus (6) from the set of heat exchangers . 2. The method according to claim 1, in which the flow rate is regulated in accordance with the temperature setting of the coolant in the return pipe after the latter, when viewed in the direction of flow of the heat exchanger (6). 3. The method according to claim 1 or 2, in which the set temperature of the supply is regulated depending on the outside temperature with respect to the system. 4. The method according to claim 1 or 2, in which the temperature set point in the return pipe is regulated in response to the regulation of the set temperature of the flow. 5. The method according to claim 1 or 2, in which the supply pipe (3) and the return pipe (4) of each heat exchanger from the set of heat exchangers are additionally connected bypass. 6. The method according to claim 1 or 2, in which the system further comprises:
a flow controller (9) connected to the return pipe (4), the flow controller being used to control the flow in the return pipe (4); an actuator (10) controlling the flow controller (9); a temperature sensor (11) located in heat exchange communication with the heat carrier in the return pipe (4). 7. The method according to claim 6, in which each flow controller (9) is additionally designed to maintain a constant flow regardless of pressure changes in the main supply pipe (1). 8. The method according to claims 1, 2 or 7, in which an outside temperature sensor (8) is installed for measuring the outside temperature with respect to the temperature system. 9. The method according to claim 8, in which an electronic controller (18) is connected to each actuator (10), and temperature sensors (11) are connected to the return pipelines (4) of the system. 10. The method according to claim 9, in which the electronic controller is connected to a temperature sensor (19) connected to the main supply pipe (1). 11. The method according to claim 9 or 10, in which each actuator is driven by pulses. 12. The method according to claim 11, in which at least one actuator (10) is an electromagnetic, pneumatic, hydraulic or electrostrictive actuator. 13. The method according to any one of claims 9, 10 or 12, in which the electronic controller (18) is configured to monitor the measured parameters and use this data to optimize the supply temperature setpoint depending on the outdoor temperature and the return temperature setpoint from the temperature setpoint filing. 14. The method according to claim 6, in which each actuator (10) is connected directly to the temperature sensor (11), is a stand-alone device and contains means for regulating the temperature setpoint in the return pipe. 15. The method according to 14, in which the actuator (10) is a thermostat. 16. The method according to any one of claims 1, 2, 7, 9, 10, 12, 14 or 15, in which the supply pipe and return pipe (4) of each heat exchanger (6) from the set of heat exchangers (6) are additionally connected bypass (5). 17. The method according to any one of claims 1, 2, 7, 9, 10, 12, 14 or 15, in which the system comprises at least two sets of heat exchangers (6) connected in series with each other and connected to one and the same main supply pipe (1) and the main return pipe (2), moreover, the flow rate in each of the aggregates is regulated separately.

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