NL2004381C2 - TEMPERATURE CONTROL METHOD AND DEVICE. - Google Patents

Description

P30137NL00/HSE

Title: temperature control method and device

The invention relates to a method for controlling a temperature in a room of a building and to a thermostatic control unit.

In heating and/or cooling systems for heating and / or cooling a room, a temperature in the room is measured by a temperature sensor. A desired temperature is entered by a person 5 or automatically set in accordance with e.g. a temperature profile over a day, week, etc. In more advanced systems, a self learing algorithm may be added, so as to e.g. determine or anticipate on a desired temperature based in behaviour in a past time period.

A goal of the invention is to provide an improved temperature control.

In order to achieve this goal, the method according to the invention comprises: 10 - performing a thermal measurement in the room with a spatial resolution temperature sensor, - determining a spatial temperature distribution from the thermal measurement, and - operating at least two heat transfer devices arranged spatially distinct in the room thereby taking into account the determined spatial temperature distribution.

The inventor has realised that a room, and its thermal characterisitics as well as its desired 15 temperature, is not a static, uniform entity. Thermal losses may vary for different parts of the room depending on e.g. whether conditions such as wind, solar radiation, etc. Also, a desired temperature profile in the room may vary as persons may be present in different parts of the room at different moments in time. These factors may be taken into account, in accordance with an aspect of the invention, by determining a spatial temperature distribution in the room by 20 means of a spatial resolution temperature sensor. The at least two heat transfer devices in the room can then be operated taking into account the measured temperature distribution, so that e.g. a desired temperature or a desired temperature distribution may be achieved in an energy efficient way. By the method, a desired temperature distribution and/or a spatial characteristic of thermal losses may be taken into account. The spatial resolution temperature sensor may be 25 any suitable temperature sensor, such as an infrared sensitive photodiode matrix, a thermal camera, a plurality of spatially distinctly positioned temperature sensors, etc. The spatial temperature distribution may be a one dimensional or two dimensional temperature distribution over at least a part of the space. A spatial resolution of the spatial temperature measurement may be set according to needs, examples will be provided in this document. The heat transfer 30 devices may be or comprise any type of heaters, such as heaters of a central heating system such as convectors, electrical heaters, integrated heaters in a floor and/or in a wall, gas firing heaters, air circulation heaters, thermal pump, etc. Furthermore, the heat transfer device may be or comprise any type of cooling device, such as an air conditioner, thermal pump, air circulating coolers, etc. Thus, the term heat transfer device may be understood so as to be any 2 device that has a potential to, when operated, alter a temperature of the room or a part thereof, either by transferring heat (thermal energy) into a part of the room, or by removing heat (thermal energy) from a part of the room. The heat transfer device may thus be or comprise any type of heat source, cold source, heat exchanger, etc.

5 In an embodiment, the method according to the invention comprises determining a contribution of one of the heat transfer devices by activating the one of the heat transfer devices, and measuring an effect of the activation on the spatial temperature distribution. Thereby, for each heat transfer device, it can be determined what its effect on the spatial temperature distribution may be, in other words in which parts of the room a temperature 10 change is provided by the activation of that heat transfer device. These steps may be repeated for each of the heat transfer devices, so that a contribution may be determined for each of the heat transfer devices. Furthermore, a configuration of the heat transfer devices (e.g. position of each of the heat transfer devices, capacity of each of the heat transfer devices and effect of each of the heat transfer devices on the temperature distribution in the room) may be 15 determined. The spatial temperature distribution may be determined from the measurement by the spatial resolution temperature sensor.

In an embodiment an energy consumption of the activated heat transfer device is measured, and an efficiency of the activated heat transfer device is determined from the effect of the activation on the spatial temperature distribution and the measured energy consumption. 20 The energy consumption may be measured by any suitable means, such as by measuring a change in the energy consumption as measured by an energy meter of the building (e.g. an electricity meter, gas meter, etc) when activating the heat transfer device in question. A relation between the effect of the activation of the heat transfer device on the spatial temperature distribution and the energy consumption associated with the operating of that heat transfer 25 device, may be taken into account, as will be explained in more detail below, when determining a strategy to achieve a desired temperature profile in the room in e.g. a most energy efficient way.

In an embodiment, the method further comprises measuring an occupancy of the room, preferably by at least one of infrared measurement, ultrasound measurement. The 30 measurement of an occupancy of the room may be taken into account to determine a desired temperature profile: On the one hand, it may be determined if the room is occupied, however it may also be determined in which part of the room the occupant or occupants is respectively are. Taking account of the part of the room in which occupancy is detected, the desired temperature profile may be set so as to heat in particular the part of the room in which 3 occupancy is detected, while other parts of the room may be heated to a lesser extent, thereby saving energy. As an example in a living room where a sofa and a dining table are provided, the heat transfer devices having an effect on heating an area where the sofa is located, may be activated to a larger extent when occupancy in the room is detected in the sofa area, while a 5 heat transfer device more proximate to the dining table may be operated when occupancy in an area where the dining table is located, is observed. Thereto, a desired spatial temperature profile may be determined in accordance with the detected occupancy, and the at least two heat transfer devices driven in accordance with the desired temperature profile. In a particularly cost effective solution, the occupancy is measured by the spatial resolution 10 temperature sensor: as a person exhibits a certain thermal radiation due to his or her body temperature, a movement of the person will provide for sudden changes in the thermal data as acquired by the temperature sensor. Processes of cooling and or heating the room however exhibit a more slow and generally less position dependent behavior. The occupancy of the room may hence be derived from relatively fast and/or local changes in the spatial temperature 15 distribution.

In an embodiment, a temperature controlling plan for controlling the temperature of the room is determined from one or more of: - the determined contribution of each one of the heat transfer devices; - the determined efficiency of each one of the heat transfer devices; 20 - the measured occupancy; and - a desired temperature profile. At least two heat transfer devices are operated in accordance with the plan. Preferably, use is made of at least the determined contribution of each one of the heat transfer devices and the determined efficiency of each one of the heat transfer devices, as it allows to determine in what way a desired temperature at a certain part of the room, or a 25 desired room temperature distribution can be determined, with a minimum energy consumption. The desired temperature distribution may thereby be obtained from measured occupancy, a desired temperature profile, etc., In this embodiment, the plan may be determined to suit a variety of optima: Preferably, the temperature control plan is determined for one of minimum energy consumption (so as to minimize energy consumption) and maximum temperature profile 30 tracing (so as to maximize user comfort for the occupant of the room). To minimize energy consumption, the system may determine which areas in the room are set to achieve a certain temperature, and determines which heat transfer elements will achieve that temperature with the least energy usage. This may be achieved by a self learning mechanism in the system (as will be explained in more detail below), based on which data can be determined which heat 4 transfer element most energy efficiently achieves that set temperature at those areas in the room. The temperature control plan may comprise a list of instructions in time, including the time when a set action will be taken, the heat transfer element that is addressed, whether that element is turned on or turned off and the target temperature at the set coordinates in the room 5 and/or time at which the action is halted. In a further embodiment, the system distinguishes between the type of energy used, specifically aimed to optimize electricity usage at times of high demand and low demand. As currently, generated electricity cannot be stored in the quantities as generated by an energy utility, it is beneficial to utilize energy management systems such as this temperature control method to lower peak demand by for instance 10 switching to gas heating instead of electric heating during office hours. In an embodiment, the method further comprises: distinguishing in the measured temperature distribution different elements of the building based on building configuration data, comparing for the different elements the measured spatial temperature distribution nominal thermal data for each element, and deriving an energy efficiency qualification from the comparison. The building configuration 15 data may identify elements of the building, such as windows, walls, floor, doors, etc. Nominal thermal data may be assigned to each of such elements. Thus, e.g. a nominal thermal loss of windows, walls, etc, may be assigned to each of these elements. Temperature measurements by the spatial resolution temperature sensor provide information on the thermal behaviour of the elements. By comparing this thermal behaviour (e.g. temperature, rate of cooling, etc) with 20 the nominal data, an identification may be made of which elements appear to exhibit a less favourable thermal behaviour, and could hence benefit from insulation or other measures and hence improve an energy efficiency of the building. A particularly relevant comparison may be made when a temperature variation over time of at least one of the elements is compared with a nominal variation over time for that element, as dynamic thermal characteristics (such as 25 cooling down behaviour and speed of heating up) may provide a particularly good information on the thermal characteristics of the elements of the building.

According to an aspect of the invention, a thermostatic control unit is provided, comprising a spatial resolution temperature sensor, an output for operating at least two heat transfer devices, and a processing unit to process data obtained from the spatial resolution 30 temperature sensor, and to drive the output, wherein the processing unit comprises a memory comprising program instructions to enable the thermostatic control unit to perform the method according to the invention. With the thermostatic control unit, the same or similar technical features and the same or similar preferred embodiments may be provided as with the method according to the invention, thereby achieving the same or similar technical effects. The 5 thermostatic control unit may be provided as a single unit in a single housing, however it is also possible that the temperature sensor is separate for installation in the room, while the processing unit of the thermostatic control unit may be provided separately or integrated into a building control/automation facility thereby allowing the thermostatic control unit to be easily 5 integrated with other control or automation facilities of the building.

The spatial resolution temperature sensor may comprise a matrix of infrared detectors (such as infrared sensitive photodiodes), which are each directable to a part of the room so as to measure a temperature in the respective part of the room. Thereby, a sufficiently accurate, yet practical and cost effective temperature detector may be provided.

10 Further advantages, features and effects of the invention will become clear from the appended drawings, in which a non limiting embodiment of the invention is shown, wherein:

Fig. 1 depicts a flow diagram of a process according to an embodiment of the invention;

Fig. 2 depicts a more detailed flow diagram of a part of the process in accordance with fig. 1; 15 Fig. 3 depicts a more detailed flow diagram of another part of the process in accordance with fig. 1;

Fig. 4 depicts a more detailed flow diagram of yet another part of the process in accordance with fig. 1;

Fig. 5 depicts a more detailed flow diagram of still another part of the process in 20 accordance with fig. 1;

Fig. 6 depicts a more detailed flow diagram of again another part of the process in accordance with fig. 1; and

Fig. 7 depicts a highly schematic view of a thermostatic control unit in accordance with an embodiment of the invention.

25 Throughout the figures, the same reference numerals refer to same or similar features.

Fig. 1 depicts a flow diagram of a process according to an aspect of the invention, to illustrate an embodiment of the method according to the invention. The process depicted in fig.

1 comprises a plurality of steps, some of which will be described in more detail with reference to following figures, in which these steps are further detailed.

30 For illustrative purposes, it is assumed here that the process is performed on a system comprising a plurality of heaters, a spatial resolution temperature sensor, a control means, such as a microprocessor or dedicated hardware, which runs the process, and data communication means to allow communication with - and/or control of the heaters. It will be 6 understood that, depending on the application, instead of heaters cooling devices or combined heating/cooling devices may be applied as well.

After starting the process in step 10, an identification of the heaters is performed in step 20 so as to learn which heaters are present in the configuration to be controlled. When the 5 heaters are identified, a configuration of the heater elements is determined in 25, so as to learn what effect each of the heaters may have on the temperature distribution in the room and on the energy consumption. Then, in 30 a thermostat program is determined thereby providing a desired temperature distribution in the room. A heating plan (which heaters to activate when and to what extent) is set up as a following step 40. Then, the heating plan is carried out in 50 10 so as to control the temperature of the room in accordance with the heating plan, thereby making use of the identified heaters, the configuration of the heaters, and the thermostat program. Additionally, an energy advice may be provided in 60, after which the process may end at 70. Naturally, the process may also be provided in a repetitive loop, e.g. to continue carrying out the heating plan in 50, or to continue a repetition of the steps 30, 40 and 50 so as 15 to continue or repeat to determine a desired temperature profile in 30, make a heating plan in 40 and carry out the heating plan in 50. Further, the step 25 or the steps 20 and 25 may be repeated periodically so as to check if any changes have been made to the system or if the learned parameters as to energy consumption, contribution of the heaters to the temperature distribution in the room require any amendments (e.g. because of a rearrangement of furniture, 20 additional insulation, closing or opening of curtains, blinds etc).

A more detailed description of the identification 20 is provided with reference to fig. 2. After starting the identification at 210, input and output ports of the thermostatic control unit which runs the process are identified at 220, so that the process learns which inputs and outputs are available to receive information and/or to provide control signals. Thereto, use may 25 be made of a thermostat configuration stored in a memory 220A. Then, via the ports, an identification request may be broadcasted in 230 to the heaters (and optionally other parts of the system). Thereto, parts of the heating system, such as the thermostatic control unit, heaters, etc may be interconnected via a suitable communication system, such as a wireless communication network (e.g. wireless local area network WLAN), a wired communication 30 network, such as Ethernet, CAN bus, USB bus, etc. Having received a response to the identification request, heaters may be selected one by one, and a user at 250 being prompted via a display or other means known per se to enter data concerning the selected heater, such as its position, size, energy source, means of temperature and/or power control, etc. When the required data has been provided, the heaters can be registered at 260 and corresponding data 7 is stored in memory 80, after which the identification ends at 270, and the process returns to the configuration 25 in fig. 1.

A more detailed description of the configuration 25 of the heaters is provided with reference to fig. 3. After starting the configuration at 310, a spatial resolution temperature 5 measurement is performed with the spatial resolution temperature sensor. Thereby, a reference temperature measurement is performed at 320 so as to provide a reference spatial temperature distribution (whereby preferably all heaters are switched off or idle, so as to be able to detect an effect of each of the heaters on the temperature distribution in the room adequately). Then, a loop is followed, the loop comprising steps 330 - 385. In each successive iteration, a following 10 heater is switched on (340), and an effect of the operation of that heater on the temperature and the temperature distribution in the room is measured (350). Thereby, a stationary behavior, e.g. the temperature after a warming up time may be detected to measure an effect of the operation of the heater in question on the stationary temperature distribution in the room, and/or a dynamic behavior, including e.g. a (e.g. local, position dependent) temperature 15 increase or decrease rate. If a change in the temperature and/or temperature distribution is not detected (360), the steps 340 and 350 are repeated for a following heater. Thereto, a counter may be increased in step 330. If in 360 however a change in the temperature and/or temperature distribution is detected, the steps 370, 375, 380 and 385 are followed. In step 370, a location of a heater is determined based on the temperature distribution within the room 20 where heaters are assumed to be located in the midst of the most rapidly increasing temperatures, as illustrated in table 1, where heaters will be assumed to be placed in the areas where the temperature has reached for example 21 degrees. Notably, in cases where the surface of the heater is visible, this measured temperature will be significantly higher than areas just outside, indicating the presence of a heater. In 375 a measurement of the additional 25 energy consumption caused by the operation of the heater in question is performed.

Characteristics of the heater in question, as derived from the energy consumption and the effect on the temperature & distribution thereof in the room, are stored in 380 in a memory 90. If a further heater is provided (385), a further iteration is performed. Otherwise, the configuration ends at 390, after which the process in fig. 1 proceeds to step 30 30 A more detailed description of the configuration 30 of the thermostat program is provided with reference to fig. 4. After starting this configuration at 410, an entry by a user of an operating mode is detected in 420. The user mode may be entered in a way known per se, e.g. by means of a menu driven user interface, a switch, buttons, or may even be (factory preset or preset at installation). Three different modes are envisaged: 8 - the user to enter temperature data over a time period and/or in a time schedule and for different parts of the room (430); - the required temperature for different parts of the room being determined automatically be the system, as will be explained in more detail below (440); and 5 - the required temperature for different parts of the room being determined by the system from historical data (450).

In the first mode, the user may enter the mentioned data in step 432. In the third mode, a date/time information may be fetched (452), followed by a selection of a suitable historic pattern (454). This may be based on a self-learning mechanism, in which a simplified 10 representation may be used for the present day of the week, based on historic temperature settings and historic location presence in the room. The (sub) process then ends at 460, after which it returns to the main process in accordance with fig. .

The steps 40 and 50 will now be explained in more detail with reference to fig. 5. In fig. 5, the setting up and carrying out of the heating plan starts at 610, after which a spatial 15 temperature distribution in the room is detected at 620 making use of the spatial distribution temperature sensor. A result of the detection is stored in below table 1.

Table 1

Room scan, temperature [C]

2ÖI 2Ï1 2ÖI Ï9| W

20 20 20 19 19"

19 19 19 19 W

19 19 19 19 Ï9" 19 19 20 20 20 19 19 20 21 2Ö"

Table 1 provides a schematic view (e.g. a top view) of the room, whereby a temperature per part of the room is stored. In this example, it can be observed that somewhat higher temperatures are detected in the parts of the room mapped in the table in the upper left and 20 lower right parts. Returning now to the flow diagram in fig. 5, as a next step a scan of the room is made in 630 to detect a presence in the room. The scan can be made with any of the sensors and/or sensing methods as described elsewhere in this document. In this example, an occupancy for a time period of 5 minutes is detected, e.g. by a repetitive measurement within such time period. A result of the scan is stored in table 2, from which is appears in this example 25 that presence is detected in the part of the room mapped to the lower right part of the table.

9

Table 2

RoomScan: occupancy (5 min) Ö1 51 Ö| Ö1 o’ Ö Ö Ö Ö o’ Ö Ö Ö Ö o’ Ö Ö Ö Ö o’ ö ö ï ï o’ ö Ö ï Ö Ö

Then, in 640 a comparison is made between the measured temperatures, and a desired temperature in a part of the room where presence has been detected. Thereto, use is made of the data stored in tables 1 and 2. Furthermore, a desired temperature profile is determined from the measured presence (i.e. occupancy) in the room. Thereto, as depicted in the example of 5 table 3, a temperature in e.g. a part of the room where the occupancy is detected, is set to a desired value, while no preference is provided for the temperature in the remainder of the room. Table 3

Room Plan Temperature [C]

No preference 2Ï 2Ï 2Ï" 2Ï 21 2Ï" 2Ï 21 2Ï" 10

Using the data of tables 1,2 and 3, in 640 the difference is now determined between measured temperature and the desired temperature, the results thereof being stored in table 4. Table 4

Temperature Difference [C]

ï ï T

ï ö T

As a nex step, in 650 a plan is made in order to achieve the desired temperature in the part where presence is detected. Thereto, Table 5 provides information on the positioning of 5 the heating elements in the room.

Table 5 Room heaters ÏDÏ

Table 5 may be obtained from the information stored in database DB2 as explained above. In the example shown here, it will be understood that heater ID1 is located in the area where the occupancy was detected, hence the resulting heating plan will involve operation of heater ID1, as schematically depicted in table. 6.

Table 6

Heating Plan [time, C] time heater- Target- In-room location

Element Temperature ï ÏDÏ 2ÏC x1,y2 2 ÏDÏ 2ÏC x1, y2 3 ÏDÏ 2ÏC x1, y2 11 4 ÏD1 20 C x1, y2 x

Then, the plan is executed in step 660, after which the process may end. Alternatively, the process may repeat for example the steps 620 - 660 in a loop.

In fig. 6, a flow diagram is depicted of a process to obtain an energy advice. After the process in started in 510, a spatial temperature distribution in the room is detected in 520 5 making use of the spatial distribution temperature sensor. Objects, such as walls, floor, ceiling, heating elements are indentified in 530, thereby making use of stored heat coefficient characteristics of typical building construction materials. This determination of the construction material is made possible by analyzing how rapidly the construction material of an object changes temperature when the heating is turned on or off. Typically, for instance glass surface 10 will adapt the inside temperature more rapidly than plaster walls, that in turn will adapt to the inside temperature faster than brick walls..

The measurement at 520 may be repeated during heating and/or cooling down, whereby a temperature change over time is determined in 540 per object. For each object, the temperature and change over time is compared to reference values for that object, so as to 15 determine an efficiency of the objects in 550. For instance, for a surface that has been identified as a brick wall in 530, there are standard constraints for the heat coefficient without insulation, and standard constraints for brick walls with insulation. Thereto, use is made of the data in database 4, allowing to determine if for instance that brick wall is insulated or not. An advice can now be provided in 560 to the user after which the process ends.

20 A schematic example of a thermostat is depicted in fig. 7. Fig. 7 shows a thermostat having a housing 5, a display unit 3 , such as an alphanumeric or graphic LCD display, a spatial resolution temperature sensor comprising in this embodiment a plurality of infrared sensitive photo diodes, e.g. having a sensitivity in a wavelength range in the 8 to 25 micrometer band, allowing to detect objects at room temperature that emit radiation mostly concentrated within 25 that bandwith. Detectors having other sensitivity wavelength ranges may be applied too. In this embodiment, an infrared transmissive window 2 may cover the infrared diodes. The window may be planar however may also act as an optical lens and thereto be provided with one or more convex or concave parts. In this example, a data entry device is provided in the form of a rotatable/push button 4, to enable a user to select a desired setting by rotating the knob (a 30 corresponding value being e.g. displayed by the display 3) while a selected value is effectuated by e.g. pressing the button 4. A communication interface (schematically indicated in fig. 7 by 6) 12 may be provided to the thermostat, e.g. a wireless network interface such as a wireless local area network, a wired local area network or any other suitable data communication infrastructure or data connection. In an embodiment, use may be made of the Zigbee protocol which may provide as advantage that the thermostat will be able to communicate with a 5 plurarity of devices, without the need to install a wired communications network through the home or office location. A Zigbee embodiment adds a dimension to the invention as there can be several reference points within the room where for instance the temperature can be measured, and compared to the temperature as calculated by the thermostat. Such a network of Zigbee chips by itself would not allow to measure how the temperature is spread throughout 10 the room, because the Zigbee chips themselves have no detection mechanism where they are placed within the room. A central definition on where these Zigbee devices should be placed within the room, may be applied, the central definition being for instance stored in the thermostat. One could use such Zigbee chips for instance to include several additional rooms in the analysis, and thereby determine if there are effects in nearby rooms when heating the 15 central room. Using the Zigbee protocol or other wired or wireless communication protocol and interface, the thermostat may communicate with e.g. a processing unit which controls the steps of the process in accordance with the invention as described above with reference to figs. 1 - 6. Such a processing unit may for example comprise a microcontroller, microprocessor or other suitable programmable device, and may form a separate control unit or be part of e.g. a 20 building automation system. Instead of such a processing unit being remote from the thermostat, it is also possible that such processing unit is comprised in the thermostat (e.g. in a low cost, compact embodiment to reduce installation and hardware costs). By means of the communication interface, and/or the communication network with which it interfaces, communication may also be performed (by the thermostat and/or by the processing unit) with 25 other items, such as the heaters, energy consumption meters, etc. Existing electric heaters may for example be provided with a connection to the communication network by means of a mains plug adapter which interconnects between a mains wall socket and a mains plug of the heater. The mains plug adapter may be arranged to switch on/off the heater by connecting or disconnecting it from the mains voltage, and may be provided with power measurement means 30 (e.g. a current measurement) to measure a power consumption of the heater. Furthermore, such mains plug adapter may be provided with a communication interface for communication with the processing unit and/or thermostat. Heaters of a central heating system may be collectively controlled by controlling a central (e.g. gas fired) heater, and/or may each be 13 individually controlled. Individual control of heaters of a central heating system may be performed by installation of remotely controllable valves.

It will be understood that the principles disclosed in this document can not only be applied to a single room. Hence, in the context of this document, the term room is to be 5 understood as to comprise any space of a building, such as a hall, office, a plurality of rooms etc. Also, it will be understood that the principles are not only applicable to heating, but may also be used for controlling a cooling of a room. Hence, where in this example the term heater is applied, it should be interpreted as also comprising a cooling device.

Claims (11)

A method for controlling a temperature in a room's departure, comprising: performing a thermal measurement in the room with a spatial resolution temperature sensor, 5. determining a spatial temperature distribution from the thermal measurement, and operating at least two heat transfer devices that are arranged spatially separately in the room, taking into account the determined spatial temperature distribution. The method of claim 1, comprising: determining a contribution from one of the heat transfer devices, by activating one of the heat transfer devices, and measuring an effect of the activation on the spatial temperature distribution. 3. Method according to claim 2, further comprising: measuring an energy consumption by the activated heat transfer device, and determining an efficiency of the activated heat transfer device from the effect of the activation on the spatial temperature distribution and the measured energy consumption. A method according to any of the following claims, further comprising: measuring an occupancy of the room, preferably by at least one of infrared measurement, ultrasound measurement. 25 5. Method as claimed in claim 4, comprising: determining a desired temperature profile, preferably from the measured occupancy in the room, and wherein the operation of the at least two heat transfer devices is carried out in accordance with the temperature profile. -15 - A method according to any one of the preceding claims, wherein a temperature control plan for controlling the temperature of the room is determined from one or more of: the determined contribution from each of the heat transfer devices; 5. the determined efficiency of each of the heat transfer devices; the measured occupation; and a desired temperature profile, and wherein the at least two heat transfer devices are operated in accordance with the plan. 10 The method of claim 6, wherein the temperature control plan is determined for one following minimum energy consumption and maximum temperature profile. A method according to any one of the preceding claims, further comprising: distinguishing in the measured temperature distribution of different elements of the building based on building configuration data, comparing for the different elements of the measured spatial temperature distribution with nominal thermal data for each element, and deriving an energy efficiency qualification from the comparison. 20 The method of claim 8, wherein a temperature variation over time of at least one of the elements is compared with a nominal variation over time for that element. 10. Thermostatic control unit, comprising: a spatial resolution temperature sensor, an output for operating at least two heat transfer devices, and a processing unit for processing data obtained from the spatial resolution temperature sensor, and controlling the output, the processing unit comprises a memory comprising program instructions which enable the thermostatic control unit to carry out the method according to one of the preceding claims. The thermostatic control unit according to claim 10, wherein the spatial resolution temperature sensor comprises a matrix of infrared detectors, each of which can be directed to a portion of the room to measure a temperature in the respective part of the room.