WO2009133283A2

WO2009133283A2 - Method for the self-balancing of a heating device

Info

Publication number: WO2009133283A2
Application number: PCT/FR2009/000391
Authority: WO
Inventors: Jean -Louis Morard; François POURRAT
Original assignee: Societe Muller & Cie
Priority date: 2008-04-03
Filing date: 2009-04-02
Publication date: 2009-11-05
Also published as: EP2283279A2; FR2929691B1; FR2929691A1; WO2009133283A3

Abstract

The invention relates to a method for the self-balancing of a heating device (1). The heating devices of the prior art comprises temperature adjustment programs (19) usually integrated in a thermostat (5). For a stationary setpoint temperature, the adjustment programs perfectly adjust the room temperature (17) but upon a change of the setpoint, the setpoint may be exceeded when the room temperature reaches the new setpoint temperature (31). To avoid this, the invention proposes to modulate the control program after a setpoint change. More particularly, the program modulation is carried out based on the charge rate (32) before the modification of the setpoint.

Description

Method of self-balancing a heating device

The present invention relates to a method of self-balancing a heating device. Such a heating device can be used both for heating air in premises and for heating sanitary water. It will be developed the case of a device for heating the air of a room, the method according to the invention can easily be adapted by those skilled in the art to other known heating devices. In order to heat a room, a heating device comprises at least one heat emitter, for example an electric radiator. The heater includes a probe and a thermostat to maintain a substantially stable ambient temperature.

The purpose of the sensor is to inform the heating device of the ambient temperature. Said probe may be an outdoor sensor, an indoor sensor, or any other type of probe for giving the heating device a reference temperature.

The function of the thermostat is to determine a temporal charge rate of the heat emitter. This charge rate must be such that it makes it possible to maintain the ambient temperature substantially equal to a temperature desired by the user. Said temperature desired by the user is called the set temperature or setpoint. The temporal charge rate of the heat emitter represents the operating ratio of the heat emitter, ie for example that a load ratio of 30% represents a heat emission of the heat emitter during 30% of its running time.

The thermostat allows a user of the heater to adjust the set temperature. In order to define said setpoint temperature, the thermostat comprises a control box, typically a mechanical or electronic device.

In the case of a mechanical control box, it may be a graduated dial. In the case of an electronic control unit, it may be a control box comprising a display device as well as adjustment buttons such as a "plus" button and a "minus" button. Such buttons allow to increase or decrease the set temperature. The set temperature is then displayed via the display device.

The heater may include one or more heat emitters. Similarly, the thermostat can be a single general thermostat for controlling one or more heat emitters or an individual thermostat incorporated in each heat emitter, or a combination of these devices. A single probe can provide information on the ambient temperature one or more thermostats.

In such a device, the room sensor raises the ambient temperature. The data recorded by the probe are sent to the thermostat. The thermostat then compares the temperature read by the sensor to the set temperature defined by the user using the thermostat.

The thermostat regulates the room temperature by setting the time charge rate of the heat emitter. Said regulation is performed according to regulation parameters well known to those skilled in the art. The temperature difference between the setpoint temperature and the ambient temperature is one of these control parameters. The regulation can, for example, be a "all or nothing" type regulation, a proportional type of regulation, a proportional integral type regulation or other. The case of a proportional type regulation will be studied later, the method according to the invention being easily adaptable by those skilled in the art to other types of regulation.

Proportional type control has the advantage of providing a stable control of the ambient temperature by changing the time charge ratio of the heat emitter as a function of the temperature difference between the set temperature and the ambient temperature. Such regulation is carried out within a temperature range. This temperature range is called the proportional band. The proportional band defines a standard deviation between the setpoint temperature and the ambient temperature for which the thermostat control type is applied.

When the ambient temperature is outside the proportional band, the thermostat sets a nominal load rate of 100% or 0%, depending on whether the ambient temperature is above or below the temperatures in the proportional band. This nominal load rate at 100% or at 0% returns as quickly as possible to the ambient temperature in values belonging to the proportional band.

During a set temperature change, the temperature difference between the temperature measured by the sensor and the set temperature is suddenly increased. This sudden increase in the temperature difference causes a need for regulation as fast as possible. This need is even more important when the ambient temperature is outside the proportional band defined by the new set temperature. In order to regulate this sudden change in the set temperature, the thermostats according to the state of the art, whatever the type of regulation applied, increase or decrease the charge rate of the heat transmitter to the maximum; that is to say that said thermostats according to the state of the art define and apply a nominal load rate of 100% or 0%.

However, in the case of an increase of the set temperature by the user, one can have a high stationary load rate. By stationary charge rate is meant the charge rate in regulation at a constant setpoint temperature preceding the setpoint temperature change. A high stationary charge rate is for example of the order of 75%.

In this case, the difference between the stationary load rate and the transition load rate is small. Transition charge rate means the charge rate defined by the thermostat during an increase in the set temperature such that the ambient temperature is outside the proportional band. The heat emission of the heating device during the transition period is only slightly greater than the heat emission of the stationary period heating device. The transitional period is the period during which the thermostats according to the state of the art define and apply the nominal charge rate to reach the new setpoint temperature. This small difference between the charging rates therefore causes a small rise in the ambient temperature.

Conversely, if the charge rate preceding the increase in the set temperature was low, of the order of 25% for example, the difference between the stationary charge rate and the transient charge rate is important. The transient heat emission is then much more important than the stationary heat emission. Such a difference in heat emission causes a significant rise in temperature and abrupt. In both cases described above, once the desired set temperature has been obtained, the heat emitter still provides additional heat for a short period of time. During this time, the ambient temperature exceeds the set temperature, it is an overheating. The lower the charge rate of the old set temperature, the greater the overheating.

In the case of a drop in the set temperature, the charge rate of the heat emitting element will decrease abruptly until the new set temperature is reached. However, again, a time is needed before the regulation works properly. During this time, the temperature will drop below the new setpoint temperature, it is then an overcooling.

One possible solution to solve this problem may be to keep in a memory changes in the rate of charge for all possible changes of instructions. Thus, the memory would have for each setpoint change, between the old setpoint temperature and the new setpoint temperature, a variation of the charge rate to prevent overheating or overcooling.

However, such a solution would be long and laborious to put in place. In addition, this solution would impose a particular storage for each room to be heated. Indeed, the variation of the charge rate can not be the same for a change of setpoint passing, for example, from 18 ° C to 22 ° C in a small room and in a large room.

A long learning phase would therefore be necessary for each heating device in order to know the variation of the charge rate avoiding overheating or over-cooling. In addition, efficient regulation of the temperature during a setpoint change could not be done instantaneously, that is to say the first time that said setpoint change to keep in memory takes place. In addition, this solution imposes an important storage of the data obtained by this learning.

This solution does not seem to avoid satisfactorily overheating or overcooling.

To solve this problem, the invention provides a method for regulation during a rapid setpoint change and avoiding overheating or over-cooling in the room. In addition, the method according to the invention does not require a large storage of data allowing such a regulation. Finally, the method according to the invention adapts to all kinds of setpoint changes, and this, regardless of the room in which is installed the heater.

For this, the method according to the invention provides for breaking down the heating time of the heating element in cycles. These cycles are intended to observe the behavior of the heater over a short period of time. According to the method of the invention, the charge rate of the heat emitter is calculated at each new cycle. However, unlike a heating device according to the state of the art, the method according to the invention defines a transient temporal charge rate which is not necessarily 100%, or 0%. More particularly, the method according to the invention calculates a temporal charge rate by means of the regulation system and modulates this temporal charge rate. Typically, the control parameters are changed during the transition period. These modified parameters are applied throughout the transition period.

Thus, if the temperature difference between the ambient temperature and the set temperature is high but the charge rate before the set temperature change is low, conventional regulation provides a large increase in the charge rate to join the new setpoint temperature as quickly as possible. This sharp increase causes significant overheating. According to the invention, the charge rate calculated by the thermostat control system is calculated with modified control parameters to prevent overheating. Typically, the calculated charge rate is modulated by taking into account the charge rate of the heat emitter before the change in the set temperature. Such a modulated charge rate is then applied to the heat emitter. The subject of the invention is therefore a method of heating using a heating device comprising a thermostat, a probe and a heat emitter, the method comprising:

a step during which the heating device is supplied with energy, a step during which the probe measures the ambient temperature,

a step during which the thermostat determines a heating order,

a step during which the energy supply of the heat emitter is regulated by means of the heating command, said heating command comprising a temporal charge rate defined as a function of regulation parameters, said parameters being stored in a data memory, a difference between the ambient temperature and a set temperature being one of these parameters, - a step during which the set temperature is modified, characterized in that:

the operating time of the heating device is decomposed into heating cycles, the temporal charge rate being calculated for each cycle by a control program, the said charge rate being equal to a proportion of the cycle during which the heat is emitted

a step is performed during which the control program is modulated to calculate a transient load rate different from a nominal load rate as a function of a stationary load ratio, said stationary load ratio corresponding to the charging rate the heater before changing the set temperature,

- The transient charge rate is applied to the heat emitter. A preferred embodiment of the invention provides that modulation of the control program takes place only during cycles during which the ambient temperature is outside a proportional band, said proportional band defining a standard deviation between the ambient temperature. and the setpoint temperature, for which the regulation is carried out without modulation. A preferred embodiment of the invention provides that the The modulation for each cycle is based on the change in temperature difference between the room temperature and the set temperature.

The invention will be better understood on reading the description which follows and on examining the figures which accompany it. These are presented only as an indication and in no way limitative of the invention. The figures show:

- Figure 1: A schematic view of a heating device according to the invention.

FIG. 2: A graphical representation of the variations of temperature and charge rate in a heating device according to the invention.

FIG. 1 represents a schematic view of a heating device according to the invention. A heating device 1 must, in order to provide said heating, be supplied with energy. This power supply can, for example, be provided by an electrical outlet 2.

Such a heating device 1 comprises a heat emitter 3, typically a radiator 3. Moreover, the heating device 1 comprises a probe 4 and a thermostat 5. The thermostat 5 and the probe 4 can be directly integrated into the radiator 3. They can also be independent of the radiator 3, for example located on a general control box for controlling simultaneously several radiators 3.

The radiator 3 comprises a resistor 6 emitting heat. This resistor 6 heats the ambient air as a function of heating commands transmitted by the thermostat 5 to the radiator 3. Typically, the thermostat 5 defines a temporal charge rate to be applied by the radiator 3.

The purpose of the probe 4 is to record a reference temperature, for example an ambient temperature. This temperature reading is carried out regularly during a step of the method according to the invention. The probe transmits to the thermostat 5 the information on the temperature recorded. The thermostat 5 comprises an input interface 7, an output interface 8, a data transmission bus 9, a microprocessor 10, a data memory 11, a program memory 12, a display device 13 and a device setting 14.

The input interface 7 allows the reception of energy and data transmitted to the thermostat 5. Typically the data sent by the probe 4 are received by the thermostat 5 via the input interface 7 of the thermostat 5. The output interface 8 is directly connected to the radiator 3. The output interface 8 transmits to the radiator 3 orders 15 of heating. These heating commands define a rate of time load 16 to be applied for the radiator 3. The radiator 3 then heats, according to said rate of time load 16, its resistance 6.

The data transmission bus 9 allows the flow of data inside the thermostat 5. Typically, the bus 9 interconnects the different elements of the thermostat 5. The data, especially concerning an ambient temperature 17 read or a set temperature 18, contained in the data memory 11, are processed by the microprocessor 10. This processing is performed according to a control program 19 stored in said program memory 12. Typically, the regulation is mainly performed as a function of the temperature set point 18, the ambient temperature 17 and the control program 19

The set temperature 18 is defined using the adjusting device 14. The regulating device 14 comprises means 20 for modifying the set temperature 18. Typically, the modification of the set temperature 18 is made with the aid of a "plus" push button 21 and a pushbutton 22 ". less ". The button 21 "plus" is used to increase the set temperature 18. The button 22 "minus" is used to reduce the set temperature 18. Such push buttons can, for example, be replaced by a mechanical dial graduated or any other means of changing the set temperature 18.

The display device 13 provides the user of the thermostat 5 with different information such as the set temperature 18, the ambient temperature 17, an operating mode of the thermostat 5 or any other useful information to the user. Such a display device 13 may be a backlit LCD display, for example. Furthermore, the thermostat 5 may include a button 23 push button on and off, or a button 24 button to change the operating mode. A stop button 23 is used to turn on or off the thermostat 5 or the entire heating device 1 controlled by said thermostat 5. The button 24 for changing the operating mode can allow to influence the operating program selected in the program memory 12 which is used by the microprocessor 10. It is known, for example, thermostats with operating programs for an economic mode, a comfort mode or a mode frost free. These operating programs are defined in the program memory 12 of the thermostat 5. The data processing by the microprocessor 10 is performed by different operating programs according to the selected operating mode.

The data processing by the thermostat 5 makes it possible to define the temporal charge rate of the radiator 3. Once the data on the charge rate 16 to be applied defined by the microprocessor 10, these data are sent via the bus 9 to the 8 output interface. The heating commands are then sent to the radiator 3. A control box 25 of the radiator 3 receives the heating commands. This control unit 25 can also be used to receive the power supply 2 necessary for the proper functioning of the heat emitter. The heating commands are analyzed by the control box 25 which causes said commands to be executed on the radiator 3.

The method according to the invention uses a control program 19 operating in a conventional steady state mode and operating with modified regulation parameters in transient regime. The stationary regime corresponds to a period without variation of the set temperature 18. The transient regime, or transition period, corresponds to the period of time during which the ambient temperature is located outside a proportional band 27. The proportional band 27 represents a standard temperature difference between the set temperature 18 and the ambient temperature 17 for which the control program 19 operates in stationary mode. This regulation can be performed by proportional control, integral proportional or any other control program known to those skilled in the art. The method according to the invention is of great interest in the case where the set temperature 18 of the heating device 1 is modified.

FIG. 2 shows graphically the variations of temperature and charge rate in a heating device according to the invention. Chart 2A shows an ambient temperature curve 17 per relative to a set temperature curve 18 as a function of time. Chart 2B shows the time-of-charge rate of radiator 3 during the same period of time as Chart 2A.

According to the invention, the operating time of the heating device is decomposed into heating cycles. Such cycles 28 are defined as a period of time whose duration is defined and fixed. Each cycle 28 may, for example, last for forty seconds or sixty seconds. The thermostat 5, the probe 4 and the radiator 3 always perform the same actions during a cycle 28. Typically the thermostat 5 repeats the same operations for defining and transmitting heating commands to the heat emitter 3.

According to the method of the invention, a charge rate 16 to be applied to the heater is determined and applied for each cycle 28. Thus, each cycle 28 comprises, according to the invention, a step during which the rate charge 16 to be applied to the radiator 3 is calculated. This charging rate 16 is calculated at the beginning of each cycle 28 as a function of the regulation parameters.

During a modification 29 of the set temperature 18, for example during an increase of this set temperature 18, if a temperature difference 30 between the ambient temperature 17 and the set temperature 18, more particularly here a difference 30 between the ambient temperature 17 and a new setpoint temperature 31 is such that the ambient temperature 17 is outside the proportional band 27 by this new setpoint temperature 31, the control program goes into transient mode. In order for the ambient temperature 17 to reach the set temperature 18 as quickly as possible, the regulation systems according to the state of the art increase the charging rate as much as possible, that is to say 100%. In such systems, the charging rate 16 is set to 100% until the ambient temperature 17 has reached the set temperature 18.

Thus, if a charge rate 32 preceding the setpoint change 29, referred to as the stationary charge ratio 32, is high, the difference 30 between a stationary charge rate 32 and a transient charge rate 33, ie the charge rate calculated after modification 29 of the set point, is low in the heaters according to the state of the art. The gap between heat remission prior to the change of temperature set point 18 and heat transfer after said modification 29 is low. The increase in the ambient temperature 17 is therefore slow. With the regulation systems 19 according to the state of the art, an overheating of small amplitude takes place.

For example, when increasing the set temperature

18, if the stationary charge rate was previously 85%, the transient charge rate defined in order to reach the set temperature 18 is 15% higher than the stationary charge rate. Thus the ambient temperature increases. she slowly.

However, if the stationary charging rate 32 is low, the difference between the stationary charging rate 32 and the transient charging rate is important with the heaters according to the state of the art. The difference between the heat emission before the change in temperature set point 18 and the heat emission after said modification 29 is important. The increase of the ambient temperature 17 is therefore abrupt and important. With the control systems according to the state of the art, when the ambient temperature 17 reaches the set temperature 18, significant overheating takes place. For example, if the stationary charge rate 32 was previously 15%, the transient charge rate 33 defined by the control program according to the state of the art, in order to reach the set temperature 18, is 85% higher. compared to the stationary charging rate. The ambient temperature 17 then increases sharply. A significant overheating then takes place when the ambient temperature 17 reaches the set temperature 18.

To avoid this overheating, the method according to the invention provides that the transient load rate 33 calculated by the control program is modulated. Such modulation is effected by means of a modification of the regulation parameters taken into account by the control program

19. A modulation program 34 makes it possible to modify said regulation parameters. Said modulation program 34 is contained in the program memory 12.

According to the method of the invention, the stationary charging rate 32 is taken into account in the control program 19 in addition to the parameters conventional regulators to define the transient charge rate.

Taking into account the stationary charging rate 32, the method according to the invention informs the thermostat 5 on the heating requirements of the room. This information makes it possible to know whether a low transient charge rate is enough to cause the ambient temperature to increase abruptly or conversely if a high transient charge rate will only slightly increase the ambient temperature. Typically, the greater the difference between the stationary charging rate 32 and the transient charging rate 33 normally calculated by the control program 19 without modulation is large, plus the difference between the calculated transient charging rate 33 with the modulated regulation parameters and the charging rate 33 The transient calculated by the unmodulated control program 19 is important.

A preferred embodiment of the invention provides that the modulated control program defining the transient charge rate 33 comprises, among other things, as control parameters a difference 36 between an old setpoint temperature 35 and the new setpoint temperature 31. The old set temperature 35 is the set temperature 18 before modification 29 of said set temperature 18. The new set temperature 31 is the set temperature 18 after modification 29 of said set temperature 18.

In this preferred embodiment, the fact of taking into account the difference 36 between the new setpoint temperature 31 and the old setpoint temperature 35 for the modulation of the transient charge rate 33 makes it possible to determine the importance of the heat emission to provide to catch up to the new set temperature 31. The greater the difference 36, the greater the heat to be emitted is important and therefore the transient load rate 33 must be important. Conversely, if this difference 36 is small, the heat to be emitted is low and therefore the charge rate 33 in transition must be low. A preferred embodiment of the method according to the invention provides for reducing the period of time devoted to the transient regime to a minimum. More particularly, the method according to the invention provides for modulating the regulation parameters only during the cycles during which the ambient temperature 17 is outside the proportional band 27. When a modification 29 of the set temperature 18, the parameters Regulations are modified only in the case where said modification 29 of the set temperature 18 is such that the ambient temperature 17 is located outside the proportional band 27 defined by the new set temperature 31. If the new set temperature 31 is such that the ambient temperature 17 is still located in the proportional band 27 defined by this new setpoint temperature 31, while the steady-state regulation parameters remain the parameters applied.

Moreover, in the case where the ambient temperature 17 is outside the proportional band 27 of the new set temperature 31, when the ambient temperature 17 reaches said proportional band 27, the method according to the invention provides for no longer modulating the rate. load 16 calculated. Typically, during a transition period, as soon as the ambient temperature reaches a value included in the proportional band 27, the process according to the invention returns to a steady state. This preferred embodiment allows a return of the ambient temperature 17 to the set temperature 18 without too abrupt variation.

The charging rate 16 to be applied to the heating device 1 is calculated at the beginning of the cycle 28. This charging rate 16 is applied for the entire duration of the cycle 28 for which it has been calculated.

Another preferred embodiment provides that the parameters defining the transient loading rate are such that they take into account the variation of the ambient temperature during said transition period. Typically, during a transition period, the transient load rate is modulated as a function of the rate at which the difference between the ambient temperature 17 and the set temperature 18 is reduced.

If the temperature difference during the current cycle 28 is significantly less than the temperature difference in the previous cycle 28, then the transient loading rate calculated for the short cycle is modulated according to this reduction. the temperature difference. Typically, if the increase in ambient temperature 17 is too great, the transient charge rate is reduced to avoid overheating. Conversely, if the increase of the ambient temperature 17 is too low, the transient charge rate is increased to reach the set temperature 18.

In order to allow the calculation of the charging rate 16 of a cycle 28 to take into account the stationary charging rate 32, the calculated charging rates 16 are stored in the data memory 11. The charging rates 16 are stored during a period of time. long enough to allow said stored data to serve as a reference for the future load rates 16 to calculate. This period of time is however short enough not to unnecessarily clutter the data memory 11 of the thermostat 5. For example, the charge rate 16 calculated for the current cycle 28 can be stored in memory for the cycles 28 of the next ten minutes calculating said charge rate 16. In such a case, the calculation of the transient charge rate 33 may take into account, for the modulation of the calculated transient charge rate, the charge rate applied ten minutes ago by the heating device 1. In a particular embodiment of the method according to the invention, provision can be made for the decomposition of the heating time in cycle 28 to consist of cycles 28 lasting sixty or forty seconds.

The method according to the invention thus avoids the creation of overheating or overcooling during a modification of the set temperature 18. In addition, the method according to the invention requires only a short time of time to adapt to a modification 29 of temperature setpoint 18, and this regardless of this change, without requiring a long learning phase.

Claims

1 - Heating method using a heating device (1) comprising a thermostat (5), a probe (4) and a heat emitter (3), the method comprising

a step during which the heating device is supplied with energy (2),

a step during which the probe measures the ambient temperature (17), a step during which the thermostat determines a heating sequence (15),

a step during which the power supply of the heat emitter is regulated by means of the heating command, said heating command comprising a temporal charge rate (16) defined according to parameters of regulation, said parameters being stored in a data memory (11), a difference (30) between the ambient temperature and a set temperature (18) being one of these parameters,

a step during which the set temperature is modified (29), characterized in that:

- The operating time of the heating device is decomposed into heating cycles (28), the time charge rate being calculated for each cycle by a control program (19), said temporal charge rate being equal to a proportion of the cycle during which heat is emitted,

a step is performed during which the control program is modulated to calculate a transient load rate (33) different from a nominal load rate, as a function of a stationary charge rate (32), said rate stationary charge corresponding to the charge rate of the heater before the set temperature is changed,

the transient charge rate (33) is applied to the heat emitter.

2 - Process according to claim 1, characterized in that the modulation of the charge rate is made according to the temperature difference between an old (35) and a new (31) setpoint temperature, said old setpoint temperature being the setpoint temperature before the change of the setpoint temperature, said new target temperature being the setpoint temperature after the modification of the setpoint temperature. conservation temperature.

3 - Method according to one of claims 1 to 2, characterized in that the modulation of the control program takes place only during cycles during which the ambient temperature is outside a proportional band (27), said proportional band defining a standard deviation between the ambient temperature and the set temperature, for which regulation is carried out without modulation.

4 - Process according to one of claims 1 to 3, characterized in that the modulation for each cycle is based on the variation in temperature difference between the ambient temperature and the set temperature. 5 - Process according to one of claims 1 to 4, characterized in that it comprises a step during which the calculated charge rate is stored in the data memory of the thermostat.

6 - Method according to one of claims 1 to 5, characterized in that the storage of the calculated charge rate is performed for ten minutes after the calculation of said charge rate.

7 - Process according to one of claims 1 to 6, characterized in that a cycle lasts sixty seconds.

8 - Process according to one of claims 1 to 7, characterized in that the modification of the set temperature is an increase in the set temperature.

9 - Process according to one of claims 1 to 8, characterized in that the stationary load rate used for calculating the transient load rate of the current cycle is the load rate calculated ten minutes ago.