WO2014053988A1

WO2014053988A1 - Predictive control method, for example for heating, and device for implementing the method

Info

Publication number: WO2014053988A1
Application number: PCT/IB2013/059035
Authority: WO
Inventors: Antoine Delley; Urs Grossenbacher
Original assignee: Pronoó Gmbh
Priority date: 2012-10-03
Filing date: 2013-10-01
Publication date: 2014-04-10
Also published as: CH707054A2

Abstract

The invention relates to a method for controlling a regulator, for example for heating a building, which uses a set value and a measured value in order to generate a command. The method further takes into account a predicted measurement value linked to external parameters and anticipating the change of said predicted value by modifying the measured value in order to generate the command in an anticipated manner.

Description

PREDICTIVE METHOD FOR CONTROLLING FOR EXAMPLE HEATING AND DEVICE FOR IMPLEMENTING THE METHOD

Reference to an earlier application

The present application claims the priority of the Swiss national application CH 01805/12 filed on October 3, 2012 in the name of the School of Engineers and Architects of Freiburg, the content of this earlier application being incorporated by reference in its entirety in this application.

Field of the invention

The present invention relates to a method and a device for controlling and regulating, for example the heating of a building or a house.

Many systems and methods exist in the state of the art. For large buildings, complex systems have been developed.

In the case of single-family houses and small buildings, basic control systems with one (or more) temperature sensor and a set value given by the user are usually only available. When the measured temperature is below the desired set value, the heating is started and when the measured value corresponds to or even exceeds the set value, the heating stops.

Such a regulation is purely passive and takes into account only the actual measurement of the temperature and its comparison with a set value.

State-of-the-art publications deal with these systems and methods of regulation.

For example, the application DE 10 2008 034 923 A1 relates to a control method of an air conditioning or heating installation. In the described method, weather forecasts are taken into account to determine a focal weather forecast (of the location of the building in question) and this local forecast is used to control the heating or cooling system. 'air conditioning.

In the application WO 2004025189, a method of controlling heat flows in at least one building by regulation means using as input parameters: at least one target value (set point) such as the desired temperature for a particular room is described , a general parameter representing a magnitude which reigns inside or outside the building and which at least indirectly influences the temperature prevailing in the ioca! particular, and at least one specific parameter which is characteristic of the particular conditions of heat flow of the particular iocal concerned, said specific parameter being, in particular, the glazed surface, the state of the insulation, the orientation of the room, the shadow of neighboring buildings and / or vegetation, the height of the building above the normal level or the coordinates of the building.

US application 20100211224 discloses a method using an algorithm to determine whether the conditions outside the building can be used to use outside air to heat or cool the building, thereby avoiding the use of a building. heating or air-conditioning system when said external conditions can be used.

The application WO 2007128783 relates to a method and device for optimizing the energy consumption in a building. Weather information is collected and appropriate commands are then determined for heating or cooling said building.

Other publications of the state of the art are the following: JP 2002082718, JP 2005158020, WO 2011 048181, JP 2005229758, WO 2011-10090, WO 9744720, US 2010 152905, WO 2011 160152, US 2012101653, US 2011 106327. , US 2010 289643, WO 2006 055334, US 6098893, WO 2009 039849, WO 00 77588, DE 2004 2004 032562, GB 2212949, US 5337955, GB 2278207.

Detailed description of the invention

An object of the invention is to provide a method and a device simpler and more effective than those currently known to optimize the regulation, in the case of heating by means of oil for example and to reduce the consumption of this product.

More precisely, the object of the invention is to propose an active and predictive system which does not only take into account a measured value and its comparison with a set value.

In addition, one of the aims of the present invention is to provide a simple, effective system that can be mounted on existing installations or be integrated into new facilities to build.

The invention will be better understood thanks to the description of embodiments thereof and the figures relating thereto in which:

Figure 1 is a block diagram of an embodiment of the method according to the invention;

FIG. 2 is a block diagram of an embodiment of a device for implementing the method according to the invention.

In the context of heating a house or a small building, as an illustrative example of application of the invention, it has been found that it may be useful to take into account weather forecasts. to anticipate a temperature change (upwards or downwards) which will have the effect of stopping or starting up the heating system according to the setpoint (temperature) defined for example by a user. In addition, the buildings also have a certain thermal inertia which is a useful parameter to take into account in a predictive logic such as that followed by the present invention.

In addition, when the building is not occupied, it is not necessary to maintain the same degree of comfort one can in this case use a schedule of occupation, typically an online calendar, which can be set to remote day using a smartphone or web browser or other equivalent means.

In a normal and passive regulation, as indicated above, the system will detect (for example) a drop in the temperature (value measured below the set point) and in reaction starts the heating (for example by lighting a burner for heat the water circuit radiators).

As the building has a certain thermal inertia, the effect of heating is not immediately felt hence discomfort for the user who, in response, may be tempted to increase the set value if he has the impression that heating is not enough. In such a case, once the building temperature has reached the increased setpoint (at the measurement level), the user will then decrease the setpoint since the reached value is higher than that desired.

Given the thermal inertia of the building, the effect of the decrease in the setpoint will not be felt immediately either, which may cause the user to reduce too much the set point and the temperature finally reached. will be lower than desired. Then enters a cycle of permanent changes of the set values that is harmful to the consumption and well-being of the user who begins to adjust recurrently the set value of the installation.

To remedy this, according to the invention, as indicated above, one takes into account, on the one hand, weather forecasts to anticipate a temperature variation (downwards or upwards) and to prepare for the implementation. route of the heating installation or at its stop.

In addition to this parameter related to the external environment, in the method according to the invention, account is taken, on the other hand, of at least the thermal inertia of the building to add an anticipation parameter in the heating control. (for its start or stop), said parameter being expressed in time constant.

In addition, the occupancy of the building is taken into account (online occupancy calendar, which can be updated by means of a smartphone or a web browser) as indicated above.

According to the invention, a correction is then made of the set value delivered to the control automata, for example a boiler, to take into account the weather forecasts, the thermal inertia of the building and the occupancy schedule. Concretely, the invention uses the parameter of the thermal inertia of the building in the form of a time constant to anticipate a command (start or stop), this anticipation being translated at the level of its order by a measured value "corrected" to this effect with a positive offset (for an early stop or negative for an anticipated start).

As a typical and illustrative example in the field of temperature control of a building, the invention operates as follows:

-) the weather forecast is analyzed to determine if the building will undergo an external temperature variation that will result in a related variation of the internal temperature of the building. The reason for this variation can be any, the only thing that matters is the forecast of a temperature variation: sun, clouds, rain, wind, general decrease or increase of temperature, heat wave, etc.

-) we also determine when (in how long) this temperature variation will apply to the building in question and the occupation of the building;

-) the expected variation (in value), the moment of its arrival and the thermal inertia of the building (in the form of a time constant) are taken into account to anticipate the start-up or shutdown of the installation of heating by an advance control of the installation so that when the expected temperature variation is applied to the building, the heating installation has already been started or stopped taking into account the thermal inertia of the building and the occupation.

The start-up or shutdown of the installation is managed by a control depending on a measured value, such as the interior temperature of the building. As seen above, this operation is passive and reacts only if there is an effective difference between the measured value and the set value.

According to the invention, in order to anticipate and take into account the thermal inertia of the building (expressed in time constant), the system corrects the measured value and replaces it with an "erroneous" value, for example with a positive or negative offset, to cause the early start or stop of the installation.

For the correction of the value, it is possible to act on several parameters as will be understood in the following.

A concrete illustrative example will provide a better understanding of the principle of the invention.

-) As part of the heating system of a building, the system detects by weather forecasts that the outside temperature will drop by 5 ° C in 48 hours.

-) the thermal inertia of the building (expressed as a time constant) is 23 hours, that is to say that it takes 23 hours for the internal temperature of the building to reach the temperature set point.

-) taking into account these parameters, the measured temperature value used for the control is corrected 23 hours (duration of the time constant illustrating the thermal inertia) before the time of the expected fall in temperature so with a negative offset to cause an early start of the installation which will compensate for the thermal inertia of the building. Thus _s when the temperature has dropped by 5X, ie building will have already reached the set temperature.

According to the invention, it is not necessary to use an external measured value such as, for example, the outside temperature or in the building, but the temperatures of the water from its boiler and that of the water which is used are used. returns to the boiler (which was therefore used for heating).

More specifically, in a heating system, according to one embodiment of the invention:

-) the setpoint controls its water temperature at the outlet of the boiler

(departure line to the building at the exit of the mixer for example), with an identical value or a difference to take account of the losses;

-) the temperature of the water returning to the boiler represents the value measured in the building (same temperature or with a difference due to losses).

-) The time constant which illustrates the thermal inertia is the time that the water returning to the boiler to reach the temperature of the water leaving the boiler, less losses.

-) for the command (start or stop), a positive or negative offset is added to the temperature of the water leaving the boiler (starting line to the building at the outlet of the mixer), Indeed, in many instaiiations, the regulation is done taking into account this value and the setpoint, on the basis of known curves. For a given set temperature T _c , it is necessary that the water leaving the boiler has a temperature T _out - To deceive the control system and cause the control, it acts on this temperature T _out by adding an offset positive or negative.

In figures for the example above we can have the following values:

-) set temperature 20 ° C

-) water temperature at the boiler outlet, for example 35 ° (depending on the curves that apply in this case)

-) temperature measured in the building 20 ° C (actual measurement)

In such a state, the heating system does not work.

Once the temperature drop has been detected at 48 hours, 23 hours before the fall (taking into account the thermal inertia value given above), the values become as follows:

-) set temperature 20 ° C

~) water temperature at the boiler outlet (corrected value with an offset of 5 ° C) 30 ° C

In such a case, the heating system starts up because the system detects a difference between the setpoint value and the measured value supplied to it (and which is corrected with a negative offset) of the outlet water and which is not at the correct temperature value to ensure the setpoint. The system anticipates the expected temperature and compensates for the thermal inertia of the building by an early start at a temperature too high, the outlet water actually having a value of 40 ° (due to the applied offset). If the weather forecasts are reversed, that is to say that they provide for an increase in temperature, the operation is identical but in the opposite direction, and we take advantage of the thermal inertia of the building to stop the installation before the effective variation of the temperature knowing that the temperature of the building will not fall sharply because of its thermal inertia.

Of course, the corrected measured value introduced into the system can be directly the final value to be measured when the weather forecast has been completed or other parameters can be taken into account to vary this value in stages or according to a slope.

In the example above, it was necessary to increase the temperature by 5 ° with a thermal inertia of 23 hours. One could for example implement a command (ie negative offsets) in stages: offset -2 for 12 hours, offset -4 for 6 hours and offset -5 for the last 5 hours before the predicted fall temperature.

These bearings, or the slope followed, may be fixed or based on the variation of the expected external temperature, or on the thermal inertia behavior of the building (slope of the temperature variation curve with respect to time).

Advantageously, the control system existing in a building is not replaced by the invention but it simply acts by superimposing a positive or negative offset to the set values (water temperature from the boiler) delivered to the existing thermal regulator (large building) of the building for an appropriate and anticipated control according to the principles of the invention.

Variations are of course possible within the scope of the present invention.

For example, the measured value (temperature) that is used for regulation may be a fixed value taken at a specific location of the building, or an average value calculated on the basis of several values measured at different locations.

Alternatively, the measured value can be that of the outside of the building considering that the temperature in the building must be identical or comparable, or depends on it according to a known rule (based for example on the thermal insulation of the building ). In this case, an internal theoretical value can be derived from the measured outside temperature.

Other parameters and values can be used to start the installation by deceiving the system and the examples given above are illustrative. These parameters may in particular depend on the application of the control of the present invention which may relate to another area than the heating of buildings.

Typically, the control system according to the invention determines the thermal time constant of the building on the basis of the temperature reading of the water sensors at the outlet and at the inlet of the boiler (index response). Other methods can of course be used for determining the thermal inertia of the building and the time constant that represents it, for example by temperature measurements in the building.

In summary, weather forecasts and a time constant of the building (representing its thermal inertia) are used to determine the value of the offset to be applied to the conventional control system. Thus, it is possible to anticipate your variations of the external temperature and to save energy while improving the comfort of the building.

As an additional parameter, it is also possible to take into account a building occupancy schedule, which can be particularly useful for a building where the rooms (rooms) are occupied by several persons (for example a school), these persons generating them- even a certain temperature during their presence, or even take into account an absence of occupation (holidays) to avoid an unnecessary start.

Preferably, the implementation system of the method of the invention comprises an application for calculating the corrected command hosted on an external server 1 or in the cloud 1, at least one sensor 2 for the measured value, a means for input 3 of the instruction (keyboard, cursor etc), a weather station 4, and regulator to apply the command for example to the boiler, in the case of an application related to heating. Communication between the elements can be based on mobile telecommunications services (GSM / GPRS or WiFi or other equivalent).

The embodiments described in the present application are illustrative and should not be considered as limiting. The principle of the present invention applies to other areas than heating.

Variations are possible within the framework of the protection sought, for example by equivalent means, and the embodiments described can be combined with one another.

Claims

A method of controlling a controller, for example for heating a building, said method using a setpoint value and a measured value to generate a command, said method further taking into account a predicted measurement value related to external parameters and anticipating the change of said expected value by modifying the measured value to generate the command in advance.

2. Method according to claim 1, wherein the regulator acts on a heating system of a building.

3. The method of claim 2, wherein the set value and the measured value are temperatures.

4. Method according to one of the preceding claims, wherein the expected value is a temperature and is related to weather forecasts.

5. Method according to one of the preceding claims, wherein the anticipation of the change takes into account a constant.

6. Method according to the preceding claim, wherein the constant is a time constant.

7. The method of claim 6, wherein the time constant is representative of the thermal inertia of the building.

8. Method according to one of the preceding claims, wherein the measured value is the temperature of the water leaving a boiler or the temperature taken in at least one room of the building or the temperature taken outside the building. .

9. Heating method of a building using at least the method according to one of the preceding claims,

10. System for implementing the method according to one of claims 1 to 8, said system comprising at least measurement sensors (2), input means (3) for its set point, communication means with a network (1, 1 '), calculation means and control means (5) for applying the command determined by the calculation means.