DESCRIPTION

Field of application of the invention

[001] The present invention can be applied in the technical field of room air conditioning and it concerns a method for controlling the temperature of an indoor environment.

State of the art

[002] It is known that a large number of air conditioning systems are available, which are suited to promote temperature regulation within an environment in such a way as to also reduce energy consumption.

[003] In particular, these types of systems are capable of regulating the temperature within small rooms, generally used in domestic or civil contexts, or within relatively large rooms such as, for example, the spaces used in industrial contexts.

[004] In most of these systems, energy optimization is achieved through careful selection of the materials used in the components that make up the system, as well as through careful design of the heat flows and physical quantities involved in the system as a whole.

[005] However, while significantly reducing overall energy consumption, the high degree of optimization that has been achieved for air conditioning systems does not make it possible to maximize the energy savings associated with the air conditioning of a room.

[006] In other words, in order to control the temperature within a room, for example by keeping it constant at a reference value set by the user, these systems require more energy than that theoretically obtained as a result of the project data.

[007] In terms of energy, the difference between the minimum value, corresponding to the project data, and the actual value of the energy absorbed by the system after its installation is determined by the inevitable heat losses intrinsic to the environment and to the particular system configuration used in that specific application.

[008] These losses are difficult to estimate in advance, but their presence can considerably modify the thermal efficiency of the system.

[009] In the attempt to improve this aspect, methods and devices have been developed which are suited to promote the conditioning of the temperature present within an environment and are able to at least partially compensate for the intrinsic losses associated with a particular application.

[0010] In particular, such systems make it possible to maintain a substantially constant comfort index within the environment; it should be clarified that the expression "comfort index" means the overall thermal sensation perceived by the user within the environment. [0011] In addition to the indoor temperature, the comfort index also takes into account other factors that are intrinsic to the environment such as humidity, air quality, leakage compensation etc.

[0012] Document JPH0886489 describes an air conditioning system configured to rapidly provide a feeling of high comfort by means of a method suited to regulate the indoor heat exchange temperature according to a substantially neutral comfort index calculated starting from a reference indoor temperature.

More specifically, the comfort index is calculated using a prescribed formula that varies according to some input parameters, such as: the ventilation angle used, the amount of ventilated air, the outside air temperature, the indoor humidity and temperature, and the heat exchange temperature.

The system comprises a plurality of sensors suited to detect certain parameters such as, for example, the temperature of the internal and external air, and can calculate a value of the internal heat exchange temperature under stable conditions using the temperature value set by the user and associated with the intake and the external environment.

Said system also comprises an electronic control unit suited to regulate the frequency with which the compressor is started and the fan rotation speed in such a way as to regulate the supply of hot/cold air into the environment for the purpose of maintaining a constant exchange temperature.

[0013] The main drawback of this solution is represented by the fact that this system makes it possible to compensate only partially for the heat losses associated with the environment and in any case does not optimize energy efficiency.

[0014] In particular, this system lacks the flexibility that is necessary to dynamically and precisely compensate for the energy losses inherent to the environment and the components used in the system.

[0015] Furthermore, the system described above takes into account a limited number of quantities associated with the external environment, and this represents a further limitation in approximating the losses associated with the environment. The documents US 2015/134124, US 2016/201933, US 2017/211837 and US 2018/058710 describe methods and/or systems for controlling the temperature of an indoor environment; however, all of the methods and/or systems described in these documents have the same drawbacks already illustrated in the preceding paragraphs. Presentation of the invention

[0016] The present invention intends to overcome the aforementioned technical drawbacks by providing a particularly efficient and highly performing method for controlling the temperature of an indoor environment.

[0017] More specifically, the main object of the present invention is to provide a method for controlling the temperature of an indoor environment that is suited to minimize the energy losses associated with the conditioning of that environment.

[0018] A further object of the present invention is to provide a method for controlling the temperature of an indoor environment that can minimize energy losses when a system intended to promote the heating of that environment is installed.

[0019] A further object of the present invention is to provide a method for controlling the temperature of an indoor environment that can minimize energy losses even when a system intended to promote the cooling of that environment is installed.

[0020] A further object of the present invention is to provide a method for controlling the temperature of an indoor environment that consists of a sequence of steps which are particularly simple to carry out.

[0021] A further object of the present invention is to provide a method for controlling the temperature of an indoor environment that can be easily applied to any type of heating/cooling system available on the market.

[0022] These objects, together with others which are illustrated in greater detail below, are achieved by a method for controlling the temperature of an indoor environment of the type according to claim 1.

Other objects that are better described below are achieved by a method for controlling the temperature of an indoor environment according to the dependent claims.

Brief description of the drawings [0023] The advantages and characteristics of the present invention will clearly explained in the following detailed description of some preferred but not limiting configurations of a method for controlling the temperature of an indoor environment with particular reference to the following drawings: - Figure 1-a shows a first diagram of the temperature trend as a function of time when heat is introduced into the environment;

- Figure 1-b shows a second diagram of the temperature trend as a function of time when the system is substantially at the equilibrium;

- Figure 2 shows a second diagram of the temperature trend as a function of time when heat is removed from the environment.

Detailed description of the invention

[0024] It is the object of the present invention to provide a method for controlling the temperature of an indoor environment A.

[0025] In particular, said method can be used to control the temperature T inside the environment A in the case where there is the need to heat or cool the same environment. [0026] In fact, it can be easily inferred from the following description that the method that is the subject of the present invention can be used at the same time to promote the heating of an indoor environment A as well as the cooling or conditioning of said environment.

[0027] The expression "indoor environment" as used in this context is intended to refer to an environment within a building, delimited by a plurality of walls, by a floor and by a ceiling.

[0028] The method comprises a first step a) of preparing a device D suited to introduce a predetermined quantity of heat Q into the environment (so as to heat it) or to extract a predetermined quantity of heat Q from the environment A (so as to cool it).

[0029] In the context of the present invention, the expression "quantity of heat" is used as a synonym for thermal energy, that is, energy supplied to an environment A in order to heat it or thermal energy removed from the same environment in order to cool it (normally also defined using the expression “negative heat”).

[0030] Conveniently, the air conditioning device D may be suited to promote the heating/cooling of the environment A through the forced circulation of a carrier fluid within a circuit associated with the environment itself.

[0031] For example, the device D can be constituted by a boiler suited to circulate water within a closed circuit.

[0032] Alternatively, the air conditioning device D can be selected from among the group comprising the devices configured to promote the chilling/cooling of an environment A without requiring the circulation of a carrier fluid. [0033] Said category of devices includes electric stoves, heat pumps, pellet stoves, etc. [0034] The method furthermore comprises a step b) of setting a reference temperature TR.

[0035] In particular, the reference temperature TR may be associated with a precise reference point PR selected within the volume contained in the indoor environment A where the following method is applied.

[0036] Conveniently, the reference temperature TR can be set in a "fictitious" manner, that is, it can be the result of a mathematical average of a plurality of reference temperatures associated with respective reference points located within the indoor environment.

[0037] The method also includes a step c) of monitoring over time the curve described by the temperature T suited to be measured at the reference point PR.

[0038] In general, this monitoring activity can be carried out by means of a thermostat suited to measure the temperature at the reference point and of a processing unit operatively connected to said thermostat.

[0039] The processing unit can be provided with a memory suited to store the trend of the temperature T associated with the reference point PR over time by storing strings of numerical data.

[0040] As better illustrated in Figure 1-a, the trend of the temperature T monitored at the reference point Tc over time may show a wave-like movement around the reference temperature Tc between a predetermined minimum value T _mm and a predetermined maximum value T _max .

[0041] This behavior is justified by the fact that the heating/cooling system associated with said environment A has a certain thermal inertia when the temperature T is lower or higher than the reference value Tc.

[0042] The term "system" is used to refer to a set of elements resulting from the combination of the air conditioning device D, any heat distribution or extraction circuit (for example, pipes, radiators, etc.), and the physical characteristics of the environment A (size and thickness of the walls, volume, thermal insulation, exposure to the sun, etc.). [0043] The combination of these elements determines a thermal inertia of the system; the expression "thermal inertia" refers to the response of the system in terms of temperature and heat when the following two conditions occur (alternately, that is, disjointedly): i) when the air conditioning device D is on and ii) when the air conditioning device D is off.

[0044] In terms of temperature, the inertia of the system results in a particular shape of the curve monitored during step e).

[0045] Said curve will therefore have minimum values T _m m, maximum values T _ma x and slopes of the various half waves expressing the correlation between the shape of said curve and the thermal characteristics associated with the system.

[0046] Conveniently, the method comprises a step d) of measurement of the minimum value T _min and/or the maximum value T _max associated with the curve of the temperature T monitored during step c).

[0047] As better illustrated in Figure 1-a, the minimum temperature value T _min is lower than the reference temperature value TR because the curve is affected by the thermal inertia offered by the system when the air conditioning device D is deactivated.

[0048] Conveniently, the step d) of measurement of the minimum value T _min and/or the maximum value T _max of the temperature T can be performed by the processing unit. [0049] The method also includes a step e) of calculation of a first heat differential Di and a second heat differential D _å .

[0050] The first heat differential Di is defined by the subtraction between the value of the reference temperature TR (representing the minuend) and the value of the minimum point T _min of the temperature curve T measured in step d) (representing the subtrahend). [0051] The second heat differential D _å is defined by the subtraction between the value of the maximum point T _max of the temperature curve T measured in step d) of the reference temperature TR (representing the subtrahend) and the value.

[0052] Also in this case, the calculation of the first heat differential Di and of the second heat differential D _å can be performed by the processing unit.

[0053] The value of the first heat differential Di remains substantially constant during the execution of step c) of monitoring of the temperature T.

[0054] This heat differential Di, in fact, represents the inertia of the system when passing from a condition of substantial comfort (in which the temperature is substantially equal to the reference temperature TR) to a condition of maximum temperature drop represented by the minimum value T _min . [0055] The temperature cannot drop below the minimum value T _mm , since at this point the temperature curve T starts to rise due to the activation of the air conditioning device D.

[0056] In other words, when the temperature falls below the reference temperature TR, the air conditioning device D is activated but its real effect on the environment begins to be perceived as soon as the temperature T reaches the minimum value T _mm .

[0057] This situation is linked to the thermal inertia developed by the system when the temperature T is below the reference temperature TR: in order to obtain variations in temperature at the reference point PR, in fact, it is necessary to wait for the air conditioning device D to compensate for the losses related to this inertia by inverting the trend of the curve of the temperature T that has been falling until that moment (thus giving origin to a minimum point T _min ).

[0058] In general, the inertia developed by the system below the reference temperature TR remains substantially constant over time, which is why the value of the first heat differential Di is substantially constant during all the activation/deactivation cycles of the air conditioning device D.

[0059] As in the temperature control methods already used in the art, also the present method includes a step f) of activation of the air conditioning device D when the instantaneous temperature T measured in step c) is lower than the reference value TR. [0060] The method includes also a step g) of deactivation of said device D when the instantaneous temperature T measured in the environment A in step c) is higher than the reference value TR.

[0061] The method furthermore comprises a step h) of repetition of step f) of activation of the device and step g) of deactivation of the device D for a predetermined number of cycles.

[0062] In the present context, the expression "temperature cycle" is intended as referring to a complete excursion of the temperature curve which therefore begins and ends at the reference value TR and moves along a first half wave (where the temperature values are all below the reference temperature TR) and then along a second half wave (where the temperature values are all above the reference temperature TR).

[0063] The total number of cycles defined by the execution of step h) may vary, depending on the case, from a few units (for example, when the environment A is small and/or has limited heat losses) to a few tens (when the environment A is particularly large or has considerable heat losses).

[0064] Conveniently, during the execution of the repetition step h), the quantity of heat Q introduced into/extracted from the environment during the step f) of activation of the device is progressively reduced until reaching a predetermined minimum value Q _m m. [0065] In particular, the quantity of heat Q introduced into/removed from the environment A during each cycle of the temperature T encountered in step h) is smaller than the quantity of heat Q' introduced into/removed from the environment A during the previous cycle (encountered during the same step h)). It can therefore be stated that Q' > Q. [0066] The quantity of heat Q introduced into/extracted from the environment A can be controlled by the processing unit by controlling the activation/deactivation time of the air conditioning device D.

[0067] Alternatively, the quantity of heat Q introduced into/extracted from the environment A can be controlled by varying the flow rate and/or the temperature associated with a carrier fluid associated with the air conditioning device D.

[0068] As explained above, during the execution of step e) of the present method, a second heat differential D _å can be calculated.

[0069] In this case, the maximum point T _max associated with each cycle of the temperature T monitored during step c) is determined.

[0070] The maximum point T _max of a given cycle may be different from the maximum point T _max ’ determined in the preceding or subsequent cycle, because the value associated with that point depends on the quantity of heat Q introduced/ extracted by the air conditioning device D during step f) of activation associated with those cycles.

[0071] As is known, said quantity of heat Q may vary depending on the customer’s requirements or other factors associated with the environment.

[0072] However, the second heat differential D _å is defined as the subtraction between the maximum value of the temperature T _max of each cycle measured in step d) (representing the minuend) and the value of the reference temperature TR (representing the subtrahend).

[0073] By means of the processing unit, it will then be possible to perform a step i) of comparison between the first heat differential Di calculated in step e) and the second heat differential D _å calculated in step i). [0074] When the value of the second differential D _å is higher than the value of the first differential Di (i.e. D _å > Di), it is possible to determine a positive result of the comparison made in step i)

[0075] Advantageously, the execution of step h) is conditional on the outcome of the comparison made during step i).

[0076] In particular, step h) will only be performed when the outcome of that comparison is positive.

[0077] As already described above, during the execution of step h), the air conditioning device D is activated and deactivated (steps f) and g)) in such a way as to introduce/remove a progressively decreasing quantity of heat Q into/from the environment A.

[0078] Therefore, the introduction into/extraction from the environment A of a quantity of heat Q which progressively decreases over time is only possible if the comparison made in step i) is positive, that is, only when the value of the second heat differential D _å exceeds the value of the first heat differential Di.

[0079] As is better described below, the object of the present method is to minimize the second heat differential D _å by making it substantially equal to the first heat differential Di. [0080] For this purpose, the method includes a step I) of calculation of the second heat differential D _å during each cycle of activation/deactivation of the air conditioning device D included in step h). The calculation of the second heat differential D _å is therefore "dynamic", meaning that it is performed during each cycle of activation/deactivation of the device D repeated in step h).

[0081] In other words, thanks to step I), it is possible to determine the second heat differential D _å for each cycle of the temperature T belonging to step h).

[0082] Even the comparison step i) is performed dynamically when a new value of the second heat differential D _å is calculated.

[0083] In this way, the processing unit can calculate the new quantity of thermal energy Q to be introduced into/extracted from the environment A (which will obviously be lower than that calculated for the previous cycle).

[0084] The progressive reduction of the quantity of heat Q introduced into/extracted from the environment does not necessarily follow a linear trend but may also follow a different decreasing curve that may be regular or irregular. [0085] Advantageously, the minimum value Q _mm of energy introduced into/extracted from the environment and representing the ideal limit to which the present method tends will be chosen (or calculated) in such a way as to determine a second heat differential D _å substantially equal to the first heat differential Di.

[0086] From the point of view of temperature, the curve comprising a maximum point T _max and a minimum point T _min deviating from the reference value TR by the same differential D is the one which makes it possible to perfectly compensate for the inertia of the system while minimizing the thermal energy Q introduced/extracted by the air conditioning device D.

[0087] When the curve follows the trend shown in Figure 1-b, the system is substantially at the equilibrium in terms of temperature and the quantity of heat Q required of the air conditioning device D to maintain this condition of balance is as small as possible. [0088] As already described above, the minimum point T _mm of the temperature T (located below the reference temperature TR in the lower half wave) is substantially determined by the thermal inertia of the system and cannot be brought closer to the value of the reference temperature TR.

[0089] Consequently, also the maximum value T _max of the temperature T (located above the reference temperature TR in the upper half wave) is affected by the characteristics of the system and is bound to the minimum point T _min through the inertia of the latter. [0090] This constraint does not make it possible to further reduce the maximum value T _max of the temperature T in the temperature curve associated with each cycle.

[0091] Step h) makes it possible to stabilize the system by setting a condition of substantial thermal equilibrium.

[0092] The method may comprise a step m) of repetition of step f) of activation and step g) of deactivation of the air conditioning device D so as to introduce/remove the minimum quantity of heat Q _mm at each cycle.

[0093] In practical terms, step m) represents a step in which the system is maintained in the condition of equilibrium.

[0094] During step m), therefore, the temperature curve T monitored in step c) has a substantially sinusoidal trend where the minimum point T _min and the maximum point T _max are substantially the same and equal to the reference value TR minus the first heat differential Di or plus the second heat differential D _å . [0095] A sinusoidal temperature curve T is in fact associated with the condition of thermal and energy equilibrium of the system, and with respect to said trends this particular shape of the curve allows the overall efficiency of the system to be maximized while minimizing heat losses.

[0096] As already explained above, the condition of energy and thermal equilibrium reached in the repetition step h) and the subsequent maintenance step m) makes it possible to compensate for the thermal hysteresis of the system.

[0097] However, the hysteresis of the system also depends on factors which are not directly related to the elements making up the system, but which may be associated with the climatic and atmospheric conditions present outside the environment A or, again, with biological parameters associated with one or more users present inside the environment A.

[0098] For example, the climatic conditions that may affect the thermal inertia of the environment A may be related to solar radiation, wind intensity, external temperature, humidity levels, atmospheric pressure etc.

[0099] Furthermore, the biological parameters associated with a user that may affect the thermal inertia of the system (at least that perceived by the user) may be related to body temperature, heart rate, blood pressure etc.

[00100] The variation of environmental/biological parameters can lead to a modification of the thermal inertia associated with the system, and this is shown by an alteration of the minimum temperature T _mm and the maximum temperature T _max measured in the temperature curve T monitored during the execution of step c).

[00101] In other words, the variation of these parameters may result in an alteration of the equilibrium point of the system; in this case, it will be possible to repeat the method steps indicated above so as to restore the thermal balance of the system itself by introducing a new optimal minimum heat quantity Q _mm calculated by the processing unit. [00102] Advantageously, the processing unit can be configured to record the atmospheric and biological parameters external to the system (by means of suitable sensors) in such a way as to obtain a univocal association between the optimal minimum heat quantity Q _mm , calculated so as to achieve the thermal balance of the system, and the climatic and/or atmospheric and/or biological parameters associated with the same system at the time when said optimal heat quantity Q _mm was calculated. [00103] In this way, the processing unit can define a univocal relationship between the conditions external to the environment and the optimal minimum heat quantity Q _mm required by the latter to achieve a condition of thermal and energy equilibrium.

[00104] In the case where in the future the conditions inside the environment A should be the same as the external conditions, the parameter-heat correlation stored in the processing unit will make it possible to immediately obtain the value of the optimal minimum heat quantity Q _mm with no need to perform again the steps of the method described above.

[00105] The application of the method described in the preceding paragraphs refers to the case in which it is necessary to introduce a certain quantity of heat Q in the environment A in order to maintain a reference temperature TR (heating of the room). [00106] In the case where the present method is applied for the purpose of cooling the environment A, that is, a certain quantity of heat Q must be extracted from the environment A in order to maintain a reference temperature TR, the steps and concepts illustrated above remain valid even if it is necessary to consider the curve shown in Figure 2.

[00107] In this case, in fact, the heat differential Di represents the inertia of the system when passing from a condition of substantial comfort (in which the temperature is substantially equal to the reference temperature TR) to a condition of maximum temperature increase, represented by the value T _max .

[00108] Therefore, the concepts expressed in paragraphs [0054] - [0067] remain valid, it being understood that, considering the diagram shown in Figure 2, the differential Di now indicates values of the temperature curve which are higher than the reference temperature TR.

[00109] Furthermore, in the case of Figure 2, the heat differential D _å is suited to determine the minimum point T _min associated with each cycle of the temperature T monitored during step c).

[00110] The second heat differential D _å is defined as the subtraction between the reference temperature TR and the minimum value of the temperature T _mm of each cycle monitored during step d).

[00111] Even in the case where the method is applied to cool an environment A, the explanation provided above shows that both the first heat differential Di and the second heat differential D _å are positive numbers (that is, numbers greater than zero). [00112] For this reason, the technical details described in paragraphs [0068] - [00104] remain valid for the implementation of the present method independently of whether the air conditioning device D is suited to promote the heating of the environment A through the introduction of a quantity of heat Q or the cooling of the environment A through the extraction of a predetermined quantity of heat Q.

[00113] The present invention can be carried out in other variants, all within the scope of the inventive features claimed and described herein; these technical features may be replaced by different technically equivalent elements, while the materials used, the shapes and dimensions of the invention may be any, provided that they are compatible with its use.

[00114] The reference numbers and signs included in the claims and in the description have only the purpose of making the text clearer and should not be considered as elements limiting the technical scope of the objects or processes they identify.