WO2014062124A1

WO2014062124A1 - Method and device for controlling the indoor temperature in a property

Info

Publication number: WO2014062124A1
Application number: PCT/SE2013/051207
Authority: WO
Inventors: Thomas Wildig
Original assignee: Ecofective Ab
Priority date: 2012-10-18
Filing date: 2013-10-16
Publication date: 2014-04-24
Also published as: SE536751C2; SE1251186A1; EP2917647A4; EP2917647A1

Abstract

Method for controlling the indoor temperature in a property comprising an existing system (210) for regulating the said indoor temperature, which system is arranged to bring a heat- or cold medium past a heating- or cooling radiator (221,231) which in turn is arranged to heat or cool the indoor air in the property by transferring thermal energy between the heat- or cold medium and the indoor air, and whereby the existing system is arranged to read the temperature of the medium via at least one input for a signal representing a measured temperature of the medium at a certain measurement location (212,213,214,215,216,217) along the path of the medium through the system. The invention is characterised in that the method comprises the steps a) determining a desired instantaneous heating- or cooling power which it is desired for the system to emit to the indoor air of the property; b) based upon knowledge of the properties of the system and used control algorithm, calculating a fictitious temperature as the fictitiously measured temperature of the medium at the said measurement location that would give rise to the desired instantaneous power; and c) feeding to the said input a signal representing the fictitious temperature.

Description

Method and device for controlling the indoor temperature in a property

The present invention relates to a device and a method for controlling the indoor temperature in a property. In particu^¬ lar, the invention relates to such control in a property which already has an existing system installed for heating and/or cooling of the indoor temperature, in which system a heat- or cold carrier is transported in a pipe work and emits heat and/or cold to the indoor air via heating or cooling radiators .

There are several known such systems, for instance systems for geothermal heating and cooling, systems for district heating and cooling, heat pump based systems for heating or cooling, and various different systems comprising local heat- or cold stores, such as locally arranged ice stores where cold from the winter season is exploited for cooling during the summer season.

Many such systems have in common that the indoor air in a property is heated or cooled by heat being emitted from, or supplied to, respectively, a heat or cold carrier circulated in a pipe work past some type of heating or cooling radiator, using which the said transfer of thermal energy is performed. Examples of such radiators are conventional passive radiators and fan coil units for heating and/or cooling of indoor air. Examples of suitable heat- and cold carriers comprise water with anti-freeze additives, and various heat carriers used in conventional heat pumps. Thermal energy can be transferred from a heat- or cold source either via a heat pump step, whereby the heat carrier is evaporated and thereafter con^¬ densed, alternatively only via heat exchange. In the follow^¬ ing, such heat- and cold carriers are denoted "mediums". Many such systems are regulated using an integrated regulat^¬ ing device, regulating the heating- or cooling power, respectively, of the system using a predetermined control algo- rithm, based upon the instantaneous operation situation in terms of for instance actual and desired values for the in^¬ door temperature.

Such control algorithms are often quite efficient for keeping the indoor temperature within a certain predetermined inter^¬ val. However, in many cases it is desirable to be able to control the power of such a system according to an alternative control algorithm, for instance with respect paid to information which the integrated regulating device is not arranged to take note of. For instance, in many cases it is desirable to be able to control such systems remotely, such as from a central control device which is arranged to control several such systems for heating and/or cooling. In order to achieve this, it is however in general required to modify or replace the integrated regulating device, which is costly.

The present invention solves the above described problems.

Hence, the invention relates to a method for controlling the indoor temperature in a property comprising an existing system for regulating the said indoor temperature, which system is arranged to bring a heat- or cold medium past a heating- or cooling radiator which in turn is arranged to heat or cool the indoor air in the property by transferring thermal energy between the heat- or cold medium and the indoor air, and whereby the existing system is arranged to read the tempera^¬ ture of the medium via at least one input for a signal repre- senting a measured temperature of the medium at a certain measurement location along the path of the medium through the system, and is characterised in that the method comprises the steps a) determining a desired instantaneous heating- or cooling power which it is desired for the system to emit to the indoor air of the property; b) based upon knowledge of the properties of the system and used control algorithm, calculating a fictitious temperature as the fictitiously measured temperature of the medium at the said measurement location that would give rise to the desired instantaneous power; and c) feeding to the said input a signal representing the fictitious temperature.

The invention also relates to a device for performing such a method.

In the following, the invention will be described in detail, with reference to exemplifying embodiments of the invention and to the appended drawings, wherein:

Figure 1 is a schematic view of a conventional system for heating or cooling the indoor air in a building;

Figure 2 is a schematic view of the system of figure 1, sup^¬ plemented with a device according to the present invention; and

Figure 3 is a schematic view of a sensor well or sensor pock^¬ et with a temperature sensor device of the invention.

Figure 1 shows a property in the form of a house 100 compris- ing a system 110 for heating and cooling, respectively, of indoor air in the house 100. It is preferred that the house 100 is an apartment building, but the invention is also ap^¬ plicable to single-family homes. The system 110 may be adapted to heat and/or cool one or more houses, in the latter case preferably several houses which are located near each other .

The system 110 is arranged to regulate the interior tempera- ture of the housing 100, and comprises for this purpose a regulating device 111 which preferably constitutes an inte^¬ gral part of the system 110.

Further, the system 110 includes a heat pump device 120 of the air-air type, arranged to transfer heat from the outside air at the house 100 to the indoor air. The heat pump device 120 is connected to a fan convector 121, via conduits 122 for a medium. In a way which is conventional as such, the heat pump device 120 is operable to heat or cool the air inside the house 100. The heating respective cooling power of the heat pump device 120 can be controlled by means of a pump 123.

Additionally, the system 110 comprises a heat exchanger de- vice 130 for receiving, via conduits 132 for an external medium, and utilizing, heat or cold delivered in the form of district heating or cooling. The heat exchange device 130 is arranged to distribute such heat or cold, via an internal medium in conduits 133 and radiators 131 inside the house 100. The heating or cooling power, respectively, of the heat exchange device 130 can be controlled by means of a pump 134.

The regulating device 111 is arranged to control the power of the heat pump device 120, by controlling the pump 123, based on measured values for the instantaneous temperature of the medium in the conduits 122, both upstream of the fan convector 121 and downstream of the fan convector 121. The temperature in question is measured by means of temperature sensors 114 and 115, respectively, connected to the regulating device 111.

Correspondingly, the regulating device 111 is arranged to control the power of the heat exchange device 130 by control^¬ ling the pump 134, based on corresponding instantaneous temperatures of the medium in the conduits 133 upstream and downstream of the radiator 131, as measured by temperature sensors 116 and 117.

For the control of the devices 120, 130, the regulating de^¬ vice 111 may also be connected to one or more outdoor temper^¬ ature sensors 113 and to one or more indoor temperature sen^¬ sors 112.

It is realized that the heat pump device 120, which produces heating or cooling energy through local heat pumping against the outdoor air, and the heat exchange device 130, which gives rise to heating or cooling through externally input such heat or cold, represents only two examples of the dif^¬ ferent systems for heating and/or cooling for which the present invention is applicable. The invention is applicable in essentially any combination of one or more different systems for heating and/or cooling based on heat pumping and/or heat exchanging, which utilizes local and/or external sources of heat and/or cold, as long as the regulating device 111 is arranged to regulate the used systems 120, 130 based on at least one instantaneously measured temperature for a medium flowing in a conduit upstream and/or downstream of a thermal load in the form of a convector, a radiator or other piece of equipment which is arranged to heat and/or to cool the indoor air in the house 100. It is preferred that the measurement point or points for the medium temperature upon which the said regulation is based is or are located indoors. The system 110 is thus arranged to convey the heating or cooling medium past a heating or cooling element 121, 131, which in turn is arranged to heat or cool the indoor air in the house 100 by transferring thermal energy between the heating or cooling medium and the indoor air, and the system 110 is further arranged to read the temperature of the medium via at least one input for a signal representing a measured temperature of the medium at a particular measurement loca- tion 114, 115, 116, 117 along the path through the system of the medium.

It is preferred that the regulating device 111 uses a per se known and conventional control algorithm so as to, as effi- ciently as possible, regulate the indoor temperature of the house 100 within an allowable temperature range, based on temperature data available to the regulating device 111. An example of such a control algorithm is a conventional PID control .

Figure 2 shows the same property with the same house 200 as in figure 1, but in which the the present invention has been applied. Figure 2 uses the same reference numerals as does Figure 1 for like parts, with respect to the last two digits of each reference numeral. The first digit of each reference numeral is always "1" in figure 1 and "2" in figure 2.

Figure 2 shows a control device 240, which can be arranged locally in the property, but which preferably is arranged outside the property. It is especially preferred that several houses 200 in several properties are connected to one and the same single control device 240, which can then control the supply of heating and/or cooling to all connected such houses 200. This provides both economies of scale and the ability to perform load balancing of the available heating and/or cooling across the connected houses 200.

It is preferred that the control device 240 is not directly connected to any actuators directly regulating the flow of medium in conduits 222, 232, 233 of the system 210, especial^¬ ly that the controller 240 is not connected to any actuators used by the controller 211 to regulate the heating and/or cooling power, such as the pumps 223, 234.

Furthermore, it is preferred that the control device 240 is not directly connected to the regulating device 211, except possibly via one or more existing inputs of the regulating device 211 for the temperature sensors 212, 213, 214, 215, 216, 217, see below.

In contrast thereto, a system according to the invention comprises a signal device which in turn is arranged to be controlled by the control device 240 and which is arranged to supply a signal representing a fictitious temperature to one or more of the existing inputs of the regulating device 211 via which the regulating device 211 is arranged to read the temperature of the medium in the form of a signal represent^¬ ing a measured temperature of the medium at a particular measurement location 214, 215, 216, 217 along the path through the system of the medium. Hence, in the example il^¬ lustrated in figure 2, these inputs are constituted by the connections to the control device 211 for the cables that run between the temperature sensors 212, 213, 214, 215, 216, 217 and the regulating devices 211.

Moreover, in the exemplary embodiment illustrated in figure 2, the signal device is constituted by connections between the control device 240 and the temperature sensors 214, 215, 216 and 217, as well as any devices directly connected to the respective measurement locations 214, 215, 216, 217. In other embodiments (see below) , the signal device also comprises, for example, connecting cables between the temperature meas- urement locations and the regulating device 211.

There are several possible ways for the control device 240, via the signal device, to feed to the regulating device 211 a signal representing a fictitious measured temperature. What is essential is that the regulating device 211 is supplied with a signal which, from the regulating device's 211 point of view, is not significantly different from a signal which would have arrived from a temperature sensor arranged for conventional use with the regulating device 211.

A first example is that the signal device 240 is directly connected to the respective input of the regulating device 211, and that the signal device 240 feeds to this input a signal, in an appropriate format which can be accepted by the regulating device 211, which signal represents the fictitious temperature .

A second example is that the respective temperature sensor 214, 215, 216, 217 is replaced with a part of the signal device, so that the existing connection between the respective temperature sensor and the regulating device 211 is used to transmit a signal representing the fictitious temperature, from the location at which the temperature sensor was originally located to the regulating device 211. Hence, in this case the part of the signal device which replaces the origi^¬ nal temperature sensor must feed the signal in a format that corresponds to that which was fed by the initial temperature sensor in question. A third example is that the input of the regulating device 211 is fed with the fictitious temperature by means of a temperature controlling part of the signal device being ar^¬ ranged to regulate, to the fictitious temperature, the tem- perature in a local environment of the existing temperature sensor 214, 215, 216, 217, which sensor is retained. Thereby, the existing temperature sensor 214, 215, 216, 217 will as^¬ sume the fictitious temperature, and therefore also feed a signal representing this fictitious temperature to the regu- lating device 211. Hence, in this case no special considera^¬ tions are required regarding signal format, since the exist^¬ ing temperature sensor is used.

Figure 3 illustrates a particularly preferred way for the signal device to supply to the regulating device 211 a signal representing the fictitious temperature, using a temperature chamber device 300 according to the invention.

The temperature chamber device 300 comprises an elongate temperature sensing device 320, positioned in a sensor well 312 disposed in a conduit 310 for the medium at the certain measuring location 214, 215, 216, 217, so that the tempera^¬ ture sensor device 320 extends some ways into the sensor well 312, and thereby is in thermal contact with the medium 311 inside the conduit 310. The conduit 310 is shown in figure 3 in cross-section.

The point where the temperature is actually measured along the longitudinal direction of the temperature sensing device 320, in the example illustrated at a temperature sensor 321 which is also used for the measurement, is however arranged outside of the sensor well 312, outside the periphery of the conduit 310 cross-section. The temperature sensor 321, which may be of per se conventional type, such as a so-called PT element, is further connected to the above said respective input of the regulating device 211 via a conduit 322. The conduit 322 and the signal format are selected so that they are compatible with the current input of the regulating de- vice 211.

A temperature regulating device 330, in the form of a temper^¬ ature chamber, is arranged to regulate the temperature of a local environment to the temperature sensor 321 so that it assumes the desired fictitious temperature. Thereby, the measurement value of the temperature sensor, which is also communicated to the regulating device 211, will be the ficti^¬ tious temperature. The temperature sensor 321 may be the existing temperature sensor, which originally was arranged inside the sensor well 312, which may also be an existing sensor well in the system, which prior to the initial step accommodated the existing temperature sensor. By this way, in a preliminary step prior to the commencement of operation according to the invention, merely supplementing an existing temperature sensor with a temperature sensor device 320 and a temperature regulating device 330, the signal device may be accomplished in a cost efficient manner.

Thus, using the temperature regulating device 330 the temper^¬ ature sensor 321 can register a fictitious temperature which differs from the current temperature of the medium 311 in the conduit 312. If instead it is desired that a signal repre- senting the actual temperature of the medium 311 in the con^¬ duit 310 is fed to the regulating device 211, this can howev^¬ er be accomplished by switching off the temperature regulat^¬ ing device 330. Then the immediately surrounding environment of the temperature sensor 321, and therefore also the temper- ature sensor 321 itself, will soon, via conduction through the device 320, reach a temperature which is close to the actual temperature of the medium 311. In this context, it is preferred that the device 320 comprises an elongated metal structure having good thermal conductivity, such as an elon^¬ gated metal tube, which runs from the temperature sensor 321 and down into the sensor well 312.

According to the invention, the controller 240 is arranged to first determine a desired instantaneous heating or cooling power that it is desired for the system 210 to deliver to the indoor air in the house 200, and then, based on knowledge of the properties of the system 210 and the regulation algorithm used, calculate a fictitious temperature as the particular fictitiously measured temperature of the medium at said meas^¬ urement location which, hypothetically, would produce the desired instantaneous heating or cooling power. Furthermore, the regulating device 240 is then arranged to, in one of the ways discussed above, feed an input, for a temperature sensor signal, of the regulating device 211 with a signal that rep^¬ resents the fictitious temperature.

Since the regulating algorithm used by the regulating device 211 is known, and typically is readily available via for instance manuals, and results in a controlled heating or cooling power based on one or more measurements from one or more temperature sensors, the control device 240 can use this knowledge to first calculate which such fictitious measure^¬ ment value or values from one or more temperature sensors that would result in a certain desired controlled power, and then feed to the regulating device 211 these fictitious meas^¬ urement values. Thereby, the regulating device 211 will use these fictitious measurement values and thus control the system 210 to the desired heating or cooling power. The actual calculation scheme for calculating one or more fictitious temperatures based upon a desired hypothetically controlled power is preferably performed by means of a soft- ware module in the control device 240, which for example by suitable choice of parameters can be adjusted to reflect any specific type of regulating device 211.

In order to increase the precision of this regulation, it is preferred that the control device 240, for each temperature sensor 212, 213, 214, 215, 216, 217 which is connected to the regulating device 211, either is arranged to feed to the corresponding input of the regulating device 211 a signal corresponding to a respective fictitious temperature measure- ment value, or is itself connected to a temperature sensor which in parallel measures the corresponding temperature. In the latter case, the control device 240 may use such parallel measured temperatures before calculating the fictitious tem^¬ perature or temperatures to be fed to the regulating device 211. In Figure 2, two such exemplifying temperature sensors 241, 242, are shown, namely for measuring, in parallel with the temperature sensors 213 and 212, respectively, the out^¬ door temperature by the house 200 and the indoor temperature of the house 200, respectively. Especially if the system 210 is a system for heating, it is preferred that the sensors for outdoor air 214 and indoor air 242 are used in this way.

According to a preferred embodiment, the regulating device 211 of the system 210 is arranged to read the temperature of the medium via at least two inputs for a signal representing a respective measured temperature of the medium at two re^¬ spective measurement points 214, 215; 216, 217 along the medium path through the system 210, between which measurement locations the medium passes a radiator 221; 231. Namely, then the fictitious temperature can be calculated as the ficti^¬ tious temperature difference for the medium after passage past the radiator 221; 231 that would give rise to the de^¬ sired heating or cooling power. In this case, both the two respective inputs of the regulating device 211 are fed with a respective temperature, where the difference between these fed temperatures is the said fictitious temperature. Espe^¬ cially in cooling systems, such regulation can take place without the signal from any other temperature sensors, howev- er possibly a temperature sensor 212 for the indoor tempera^¬ ture in the house 200, to the control device 211 neither needing to be overridden or be replicated, using the sensor 242, to the regulating device 240. It is particularly preferred that the system 210 in this case is a system for cool- ing of indoor air, where the cooling is achieved either via district cooling or local cooling using for instance a cool^¬ ing heat pump or a local cold storage.

The regulating device 211 is typically of so-called black box type, and can in any event not easily be affected more than to a limited extent with respect to its regulation of the system 210, in particular not via automation. Using the present invention, there is provided an opportunity for the control device 240 to accomplish such an automated impact 211, without that the actual control algorithm as such used by the regulating device 211 has to be adjusted. Therefore, information regarding factors other than those known to the regulating device 211 can be used for optimizing the regulation of the system 210.

Such additional information comprises information about fu^¬ ture events, such as experiential or planned use of the house 200, such as information that a conference will last for a set time, after which substantially fewer people will be in the house 200; or weather forecasts. Other examples of addi^¬ tional information may include knowledge of, for example, current solar radiation incident onto the house 200, espe^¬ cially with regard to differences in solar radiation onto different rooms of the house 200, and current operating con^¬ ditions for a central heating or cooling source, such as that a cooling plant approaches its maximum power. With such knowledge, appropriate actions can be taken, such as to regu^¬ late down the cooling power for some time before the confer- ence ends; to start heating some time before one or more rooms are to be used, or before an expected cooling of the local weather; to implement automatic control according to algorithms that are not supported by the existing regulating device 211, such as to reduce cooling during weekends in office spaces; to accept temporarily higher temperatures in some rooms onto which the present insolation is unusually strong; to increase the cooling or heating power during times of day when the electricity tariff is lower, or to handle power peaks during the operation of a central facility for cooling or heating by distributing the available power over a number of properties without departing from a desired respec^¬ tive temperature range more than necessary.

In order to obtain such information, the control device 240 may be connected to an external information source 243, such as a server for the weather forecasts, the Internet or any other suitable externally and/or centrally arranged source of information . In an especially preferred embodiment, an existing system 110 is supplemented with a control device 240 as described above. This way, the flexibility of temperature regulation in the house 100 can be increased in a cost efficient and easy way. Correspondingly, in this way a number of properties can be interlinked to a common control system comprising the control device 240, so that a centralized temperature control of multiple properties can be achieved at relatively low cost. It is furthermore preferred that the above inputs to the regulating device 211, for signals from temperature sensors 212, 213, 214, 215, during operation of the system 210 are fed with a signal representing the actual temperature of the medium at the respective measurement location, except when a certain future event is expected to occur. In other words, during operation of the system there is in this case arranged a temperature sensor that continuously measures the actual temperature of the medium at the respective measuring loca^¬ tion.

The future event in question is of a type that affects the need for heating or cooling of indoor air ahead, and may for example be of one of the above discussed types. Preferably, it is a temporally discrete future event with a well-defined start and a well-defined end.

In view of or prior to such an event, according to this embodiment the above input is instead temporarily fed with a signal representing the calculated fictitious temperature, so that the system 210 heats or cools the indoor air with a different power than would have been the case if the input in question all the time would have been fed with a signal rep^¬ resenting the actual temperature. The corresponding can be performed after the event has ended. In this way, the func- tionality of the system 110 is therefore extended in a cost efficient and simple way.

Above, preferred embodiments have described. However, it is apparent to the skilled person that many changes can be made to the disclosed embodiments without departing from the basic idea of the invention.

For example, it will be appreciated that more temperature sensors than the illustrated ones 212-217 can be used, in the corresponding way. Other types of sensors, such as light sensor and clocks, can of course also be connected to the regulating device 211.

Also shown in the figures are connections between the control device 240 and the temperature sensors 212-215, as well as between the temperature sensors 212-217 and the regulating device 211, in the form of fixed cable links. It is under^¬ stood that these connections can also be arranged, for exam^¬ ple, in the form of wireless connections, or connections over the Internet. This also applies to the connection between the control device 240 and the external data source 243.

Finally, the regulating device 111, 211 may regulate the heating and/or cooling devices 120, 130 in other ways, that are conventional as such, apart from controlling the pumps 123, 134.

Thus, the invention is not to be limited to the described embodiments, but can be varied within the scope of the en^¬ closed claims.

Claims

C L A I M S

1. Method for controlling the indoor temperature in a prop^¬ erty comprising an existing system (210) for regulating the said indoor temperature, which system is arranged to bring a heat- or cold medium past a heating- or cooling radiator (221, 231) which in turn is arranged to heat or cool the in^¬ door air in the property by transferring thermal energy between the heat- or cold medium and the indoor air, whereby the existing system is arranged to read the temperature of the medium via at least one input for a signal representing a measured temperature of the medium at a certain measurement location (212,213,214,215,216,217) along the path of the medium through the system, and whereby a control device (211) belonging to the existing system is arranged to, based upon the value for the said measured temperature, control the existing system to emit an instantaneous heating- or cooling power, c h a r a c t e r i s e d i n that the method compris^¬ es the steps

a) determining a desired instantaneous heating- or cool^¬ ing power which it is desired for the system to emit to the indoor air of the property;

b) based upon knowledge of the properties of the system and the used control algorithm, calculating a ficti^¬ tious temperature as the fictitiously measured tem^¬ perature of the medium at the said measurement loca^¬ tion that, via said control device, would give rise to the desired instantaneous power; and

c) feeding to the said input a signal representing the fictitious temperature.

2. Method according to claim 1, whereby the system (210) is arranged to read the temperature of the medium via at least two inputs for a signal representing a respective measured temperature of the medium at two respective certain measure^¬ ment locations (214, 215; 216, 217) along the path through the system of the medium, between which measurement locations the medium passes the radiator (221;231), c h a r a c t e r - i s e d i n that, in step b) , the fictitious temperature is calculated as the fictitious temperature difference for the medium after passage past the radiator that would give rise to the desired power, and in that, in step c) , both inputs are fed with a respective temperature each, where the differ- ence between these fed temperatures is the fictitious temper^¬ ature .

3. Method according to claim 1 or 2, c h a r a c t e r i s e d i n that the input is fed with the fictitious tem- perature by means of the temperature in a local surrounding to an existing temperature sensor (321), which is connected to the input, being controlled to be the fictitious tempera^¬ ture .

4. Method according to any one of the preceding claims, c h a r a c t e r i s e d i n that, in an initial step, a temperature sensor device (320), comprising a temperature sensor (321), is positioned in a sensor well or sensor pocket (312) arranged in a conduit for the medium at the certain measurement location, so that the temperature sensor device extends some ways into the sensor well but so that the point at which the temperature is actually measured along the tem^¬ perature sensor is arranged outside of the sensor well, wherein the temperature sensor device is connected to the input, and in that, in step c) , the signal is fed to the input by means of the temperature in a local surrounding to the said point being regulated to the fictitious temperature so that the measurement value of the temperature sensor de^¬ vice becomes the fictitious temperature.

5. Method according to claim 4, c h a r a c t e r i s e d i n that the sensor well (312) is an existing sensor well in the system (210), which prior to the initial step accommodat- ed an existing temperature sensor.

6. Method according to any one of the preceding claims, c h a r a c t e r i s e d i n that the input during operation of the system (210) is fed with a signal representing the actual temperature of the medium at the measurement location (214,215,216,217), except when a certain future event is expected to take place, which event affects the future need for heating or cooling of the indoor air, whereby the input instead temporarily is fed with a signal representing the fictitious temperature so that the system heats or cools the indoor air at another power than what would had been the case had the input all the time been fed with a signal represent^¬ ing the actual temperature.

7. Method according to any one of the preceding claims, c h a r a c t e r i s e d i n that the system (210) is a system for cooling of indoor air, where the cooling is achieved via either district cooling or local cooling by the use of a cooling heat pump or a local cool store.

8. Device for controlling the indoor temperature in a prop^¬ erty comprising an existing system (210) for regulating the said indoor temperature, which system is arranged to bring a heat- or cold medium past a heating- or cooling radiator (221, 231) which in turn is arranged to heat or cool the in^¬ door air in the property by transferring thermal energy between the heat- or cold medium and the indoor air, whereby the existing system is arranged to read the temperature of the medium via at least one input for a signal representing a measured temperature of the medium at a certain measurement location (212,213,214,215,216,217) along the path of the medium through the system, and whereby a control device (211) belonging to the existing system is arranged to, based upon the value for the said measured temperature, control the existing system to emit an instantaneous heating- or cooling power, c h a r a c t e r i s e d i n that the device compris^¬ es a control device (240), arranged to determine a desired instantaneous heating- or cooling power which it is desired for the system to emit to the indoor air, and, based upon knowledge of the properties of the system and the used con^¬ trol algorithm, to calculate a fictitious temperature as the fictitiously measured temperature of the medium at the said measurement location that, via said control device, would give rise to the desired instantaneous power, and in that the device further comprises a signal device arranged to be con^¬ trolled by the control device and to feed to the said input a signal representing the fictitious temperature.

9. Device according to claim 8, whereby the system (210) is arranged to read the temperature of the medium via at least two inputs for a signal representing a respective measured temperature of the medium at two respective certain measure^¬ ment locations (214, 215; 216, 217) along the path through the system of the medium, between which measurement locations the medium passes the radiator (221;231), c h a r a c t e r i s e d i n that the control device (240) is arranged to calculate the fictitious temperature as the fictitious tem^¬ perature difference for the medium after passage past the radiator that would give rise to the desired power, and in that the control device is arranged to, via the signal de^¬ vice, feed both inputs with a respective temperature each, where the difference between these fed temperatures is the fictitious temperature.

10. Device according to claim 8 or 9, c h a r a c t e r i s e d i n that the device comprises a temperature regu^¬ lating device (330), arranged to regulate the temperature in a local surrounding to an existing temperature sensor (321) to the fictitious temperature, and in that the existing tem^¬ perature sensor is connected to the input.

11. Device according to any one of claims 8-10, c h a r a c t e r i s e d i n that the device comprises a temperature sensor device (320), in turn comprising a temperature sensor (321), which is positioned in a sensor well or sensor pocket (312) arranged in a conduit (310) for the medium at the cer^¬ tain measurement location, so that the temperature sensor device extends some ways into the sensor well but so that the point at which the temperature is actually measured along the temperature sensor device is arranged outside of the sensor well, in that the temperature sensor device is connected to the input, and in that the signal is fed to the input by means of the temperature in a local surrounding to the said point being regulated by a temperature regulating device (330) to the fictitious temperature, whereby the measurement value of the temperature sensor device becomes the fictitious temperature .

12. Device according to claim 11, c h a r a c t e r i s e d i n that the sensor well (312) is an existing sensor well in the system (210), and in that the system has been modified so that an existing temperature sensor, which previously was accommodated in the sensor well, has been replaced with the temperature sensor device (320) of the device.

13. Device according to any one of claims 8-12, c h a r a c t e r i s e d i n that the control device (240) is arranged to, during operation of the system (210), feed the input with a signal representing the actual temperature of the medium at the measurement location (214,215,216,217), except when a certain future event is expected to take place, which event affects the future need for heating or cooling of the indoor air, whereby the control device is arranged to instead feed the input with a signal representing the fictitious tempera^¬ ture so that the system heats or cools the indoor air at another power than what would have been the case had the input all the time been fed with a signal representing the actual temperature.

14. Device according to any one of claims 8-13, c h a r a c t e r i s e d i n that the system (210) is a system for cooling of indoor air, where the cooling is achieved via either district cooling or local cooling by the use of a cooling heat pump or a local cool store.