FIELD OF THE INVENTION

The present invention relates to techniques for constructing adaptive walls which change the thermal-physical properties thereof as a function of the indoor comfort conditions required and outdoor environmental conditions, resulting in a significant energy saving.

KNOWN PRIOR ART

As for the knowledge of the inventors, there is no similar suggestion on the construction scene, given that no varying thermal transmittance system is yet available, with the exception of apparatuses which include walls with modifiable air gaps, but the effect of which on the overall varying thermal insulation properties is limited and difficult to control.

Document W02017/15100 A1 describes a system for adjusting the temperature of a building which comprises (see Figure 10) a wall facing an inner portion of the building, an insulating wall which partially covers the wall, an outer shell which delimits the building from the outside, a first duct and a second duct, in which the first duct is placed between the insulating wall and the outer shell, and/or in which the second duct is placed between the insulating part and the part facing an inner portion of the building. Therefore, with this solution, the two series of pipes are positioned at the two faces of the insulating wall, i.e., straddling the insulating wall.

By way of example, if on occasion of the summertime behavior of the walls, the circulation of the fluid is promoted at night by bringing heat from the inner portion of the building to the outside, there is a dual negative effect with respect to the pipes installed at the ends of the insulating wall. The first is that a reduced heat drop can be counted on considering that the solid part of the wall facing the inner portion of the building does not participate in controlling the system. The second is associated with the intrinsic transitory properties of the application. The cooling of the inner surface in contact with the environment occurs with an even significant delay, considering the mass of the wall facing the inner portion of the building which is not touched by the pipes, thus decreasing the heat that the wall can disperse as a whole outwards, as is known from the theory of the temperature step set on a surface [Carslaw and Jager, “Conduction of heat in solids”, Oxford, 1959, pp. 58-60]. Document GB 242650A instead describes a heat exchanger panel comprising an insulating layer (see Figure 11 ) mounted adjacently to a solid wall of a building. The heat exchanger panel comprises ducts which are connected by means of a fluid circuit to solar panels located on the roof. The heat exchanger panel can be part of an air conditioning system for a building consisting of a combination of a radiant heating or cooling system to best keep the desired temperature in the building. The system can comprise solar panels and radiant cooling plates.

Also in this case, the two series of pipes are positioned at the two faces of the insulating wall.

Thereby, the temperatures involved are the outdoor temperature and/or the temperature of the indoor environment (if there is no direct correlation with the temperature of the circulating fluid due to the interposition of the solid layer of the building wall) or the temperature of the solid layer of the building wall (if there is no direct correlation with the temperature of the indoor environment).

SUMMARY OF THE INVENTION

The present invention relates to techniques for constructing walls with a dynamic thermal behavior, i.e., walls for buildings which are capable of varying the thermal insulation capability thereof as a function of the temperatures inside and outside the buildings. Such a property is obtained through the embedding, in any horizontal, vertical or oblique wall made of any material, of pipes made of plastic, metal material, or other materials usually used for transporting liquids, in which a heat transfer fluid flows, moved by a thrust member such as a pump, for example, and the function of which consists in transporting the heat in the direction of the thickness of the wall, from the inside to the outside, and vice versa.

The problem that the invention aims to solve is that of constructing adaptive walls which change the thermal-physical properties thereof as a function of the indoor comfort conditions required and outdoor environmental conditions thereof, with negligible energy consumption, and in any case considerably less than the energy saving achieved. The control of the system is associated with two temperature sensors, one located in the outdoor environment and one located indoors: the differential value thereof guides the switching ON and switching OFF of the thrust member or pump.

If, in the wintertime, the walls generally are more performing the greater the thermal insulation capability thereof, the physics of the building are more complex in the shoulder and summer seasons. The solar radiation in the late fall and early days of spring can heat the outer surfaces of the walls and the heat can be immediately transported into the buildings, thus providing environmental heat.

In the summer, the outdoor temperature is lower than the indoor thermal wellbeing setpoint temperature for a non-negligible number of hours in the day (especially the nighttime hours). The transmission of heat (from the inside to the outside) in such periods is facilitated by the device, which in fact significantly reduces the thermal insulation of the wall.

When the thrust member (pump) is switched OFF, the wall thermally behaves as a conventional wall. The object of the present invention is achieved by virtue of an adaptive wall comprising, embedded in the wall, a duct which extends more into the innermost layer of the inner wall and into the outermost layer of the outer wall. Inside the duct, a heat transfer fluid which usually is stationary in the resting condition is present, and is free to move and circulate in the duct by virtue of a thrust member. The thrust member is adapted to move the fluid from the resting condition to cause it to flow inside the duct. A first indoor surface temperature probe and a second outdoor surface temperature probe are provided in the wall, which are positioned embedded in the innermost layer of the inner wall and in the outermost layer of the outer wall, respectively, to measure the indoor and outdoor temperature. The adaptive wall further includes a control unit which acquires the data measured by the first and second temperature probes, compares them and controls the thrust member to leave the heat transfer fluid stationary or cause it to flow according to the results of such a comparison of the indoor temperature with the outdoor temperature.

In embodiments, the wall is made of any material and the two layers where the pipe forming the duct is embedded are made of a material with high thermal conductivity. In various embodiments, the material with high thermal conductivity is selected from plasterboard, cement, and other construction materials having similar thermal conductivities.

Moreover, the adaptive wall preferably comprises an outer wall, an intermediate wall, which in turn can comprise one or more layers, and an inner wall.

In various embodiments, the indoor temperature probe is positioned in the middle of the wall, away from heat bridges and away from heat sources, and is embedded in the inner wall.

Similarly, the outdoor temperature probe is positioned in the middle of the wall, possibly at the indoor temperature probe, it also away from heat bridges and protected from rain, and is embedded in the outer wall. Preferably, the pipes forming the duct provide for a part of the trajectory to be in the vicinity of the outer wall and a part of the trajectory to be close to the inner wall. Preferably, but not necessarily, the pipes forming the duct have a coil-shaped trajectory or a round trip extension.

In certain embodiments, the adaptive wall is divided into several parts, each crossed by an independent trajectory of duct, and there is a thrust member for each part of the wall.

Alternatively, there is a single thrust member associated with a system of manifolds with the control of each trajectory on the valve of the manifold.

In certain variants, it is possible to provide for the control unit to also operate with Proportional-Integral-Derivative adjustment mode which optimizes the switching ON or OFF times of the thrust member as a function of the heat transfer in the desired direction.

In various embodiments, the thrust member is selected from a pump with a fixed number of rpm, a pump with three rotation speeds, or a member provided with an inverter which allows the typical curve thereof to be continuously varied.

Preferably, the pipes forming the duct are made of a material selected from plastic, copper, iron.

The heat transfer fluid is selected from pure water and water with the addition of other substances, such as additives, for example, in particular glycol which inhibits freezing.

The additive has varying percentages between 10% and 40% according to the climate zone in which the device is installed. The temperature probes (Tpi, Tpe) are thermocouple probes, in particular T-type probes with constantan copper junction.

The duct has a continuous-exchange path in which the pipe alternates inner segments contained in the inner wall with outer segments contained in the outer wall (PE), in which connection segments are present between the inner segments and the outer segments.

In certain embodiments, the duct has a spiral path from the periphery to the center and from the center to the periphery, both in the inner wall and in the outer wall.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the invention will become apparent from the following description provided by way of a non-limiting example, with the aid of the figures shown in the accompanying drawings, in which:

- Figure 1 shows an example of perspective view of a wall according to the invention,

- Figures 2 show implementing details of the wall in Figure 1 ,

- Figure 3 shows a flow chart of the operating algorithm of the wall,

- Figure 4 shows an example of an embodiment,

- Figure 5 shows an example of an embodiment with multiple walls,

- Figures 6, 7, and 8 show certain alternative embodiments,

- Figure 9 shows possible arrangements of the suggested solution on various vertical and horizontal walls,

- Figures 10 and 11 relate to the prior art and show the differences with respect to the solution suggested herein.

The parts according to the present description have been depicted in the drawings, where appropriate, with conventional symbols, showing only those specific details which are pertinent to understanding the embodiments of the present invention, so as not to highlight details which will be immediately apparent to those skilled in the art, with reference to the description provided below.

DETAILED DESCRIPTION OF THE INVENTION

The solution provided below is based on techniques for constructing adaptive walls which vary the thermal-physical properties thereof as a function of the indoor comfort conditions required and the outdoor environment conditions. The technology is very simple, it involving a duct crossed by a fluid and a small pump connected to a control system which allows the operation thereof when required. The fluid flowing in the duct can simply be water, but a mixture of water with added glycol is more advisable to prevent the fluid from freezing during the wintertime.

The installation consists in installing a series of pipes in the walls in order to cover the walls, and can be performed by a plumber; the electronic part requires connecting the temperature probes with the pump and with the control unit.

The areas of main application are all newly built buildings and all buildings for which it is possible to intervene on the inner and outer side of the shell.

The operating logic is now described referring to Figure 2, where all the components forming the solution suggested herein can be identified.

The solution includes the employment of a duct or a pipe 1 embedded in the wall, which puts the innermost layer SI of the wall in thermal communication with the outermost layer SE thereof.

Wall P as a whole can be made any material so long as the two layers where pipe 1 forming the duct is embedded - i.e., the outermost layer SE and the innermost layer SI - are made of a material with high thermal conductivity such as plasterboard or cement, for example. In particular, wall P comprises an outer wall PE, an intermediate wall PM, which can also be formed by one or more layers, and an inner wall PI.

Inside duct or pipe 1 , a fluid 2 which usually is in the resting condition is present, and can be caused to flow in pipe 1 by virtue of a movement pump 5. The movement pump 5 pushes fluid 2 and causes it to flow in pipe 1. Two surface temperature probes 3 are also provided, an inner one Tpi and an outer one Tpe, to be positioned, by embedding them, in the innermost layer SI of the wall, i.e., in the inner wall Pi, and in the outermost layer SE of the wall, i.e., in the outer wall PE, of wall P, respectively.

In preferred embodiments, probe Tpi is to be positioned in the environment, in the middle of the wall, away from heat bridges (for example, fixtures, balconies, windows or sills) and away from heat sources (radiators, fireplaces, heaters, convector heaters); the embedding in a few millimeters in the inner wall PI ensures the effectiveness thereof.

Similarly, also probe Tpe is to be positioned outside the building, in the middle of the outer wall PE, possibly at probe Tpi, away from heat bridges and protected from rain; the embedding in a few millimeters in the outer wall PE ensures the effectiveness thereof.

Moreover, the adaptive wall (P) faces an indoor environment in which the indoor temperature (Tpi) is measurable and faces an outdoor environment in which the outdoor temperature (Tpe) is measurable.

To be clear, "faces/facing" means there are no other layers or walls interposed between the inner wall and the indoor environment and between the outer wall and the outdoor environment.

Accordingly, the indoor Tpi and outdoor Tpe surface temperature probes 3 which are embedded in the innermost layer SI of the wall, i.e., in the inner wall Pi, and in the outermost layer SE of the wall, i.e., in the outer wall PE, of wall P, respectively, measure the actual temperatures of the indoor environment and outdoor environment.

Thereby, the system input temperatures are exactly the indoor temperature of the inner wall and the outdoor temperature of the outer wall, there being no intermediate layers between the inner wall and the indoor environment and between the outer wall and the outdoor environment.

Thereby, the efficiency of the solution is maximum. Moreover, the suggested solution is particularly effective because the pipes completely bypass all the components of the walls on which they are installed, thus generating a quick response to the transitory variations of the environmental characteristics. Moreover, with the suggested solution, the input temperatures of the suggested system are exactly the indoor temperature of the inner wall and the outdoor temperature of the outer wall.

Contrarily, in the known solutions, the effect of the pipes stops before the solid layer, thus leaving unaltered the thermal inertia of the latter and considerably slowing down the response and efficiency of the whole system to the thermal stresses of the surrounding environment which can also vary in the space of minutes.

Moreover, the solution suggested herein is applicable to any existing wall, or alternatively can be integrated in new walls, without design constraints to the stratigraphy.

This results in an advantage in terms of efficiency and application opportunities, given that it is no constraint to the (new or existing) walls on which said solution is to be applied.

A control unit 4 which acquires the data measured by the two temperature probes Tpi and Tpe and which accordingly controls the switching ON and switching OFF of the movement pump 5, is also provided.

With reference to the block diagram in Figure 3, there is a need to differentiate the operation in the hot summertime from that in the cold wintertime.

At a step 10, the Tpi and T pe temperature probes 3 measure the indoor temperature Ta and the outdoor temperature Tb, respectively.

At a step 20, the control unit 4 reads the temperatures Ta and Tb measured by the Tpi and Tpe temperature probes 3. In the case of wintertime, at a step 30, the control unit 4 compares the two temperatures Ta and Tb measured by the probes Tpi and Tpe. At a step 35, if the outdoor temperature Tb measured by probe Tpe is lower than or equal to the indoor temperature Ta measured by probe Tpi, the movement pump 5 is kept switched OFF. At a step 40, if the outdoor temperature Tb measured by probe Tpe is higher than the indoor temperature Ta measured by probe Tpi, the movement pump 5 is switched ON to cause fluid 2 to flow in pipe 1 forming the duct. The control returns to step 20 both from step 35 and from step 40, for example every 5 minutes, to define the new condition that evolved over time.

At a step 50, related to summertime, the control unit 4 compares the two measured temperatures Ta and Tb measured by the probes Tpi and Tpe. At a step 55, if the outdoor temperature Tb measured by probe Tpe is lower than the indoor temperature Ta measured by probe Tpi, the movement pump 5 is switched ON to cause fluid 2 to flow in pipe 1. At a step 60, if the outdoor temperature Tb measured by probe Tpe is higher than or equal to the indoor temperature Ta measured by probe Tpi, the movement pump 5 is kept switched OFF. The control returns to step 20 both from step 55 and from step 60, for example every 5 minutes, to define the new condition that evolved over time. In the cold wintertime, as long as temperature Tb of the outer wall PE remains lower than that of the inner wall Pi, pump 5 is inactive and wall P behaves as a conventional insulating wall in terms of thermal insulation. When the two temperatures are inverted, i.e., when temperature Tb of the outer wall PE becomes higher than the inner temperature Ta for any reason (the arrival of solar radiation, increase in the air temperature in hot climates and away from minimum winter temperatures), pump 5 is activated because there is every interest to transfer the heat from the outside to the inside. The switch ON input for pump 5 is given by the control unit 4 following the reading of the indoor temperature Ta measured by probe Tpi and outdoor temperature Tb measured by probe Tpe. With pump 5 operating, fluid 2 flows in pipe 1 and becomes the heat carrier from outdoors to indoors.

The operating principle is exactly the same in summertime operation, with the exception of the switching ON mode of pump 5, which is only activated when the temperature Tb of the outer wall PE is lower than the temperature Ta of the inner wall PI since the heat is to be transported from the inside to the outside in the hot season.

The diameter of the pipes 1 can take any value and the path of the pipes themselves can go in any direction so long as there is a part of the trajectory which is in the vicinity of the outer wall PE and a part of the trajectory which is close to the inner wall PI.

An example of first trajectory is shown in Figure 2, while a second type of trajectory, different from the first one, is indicated in Figure 4.

The closed path of pipe 1 can be applied to a portion of wall, a whole fagade or to the shell of a building. If the walls of a building are divided into several parts, each crossed by an independent loop, a thrust member or pump 5 can be used for each subdivision, as shown in Figure 2, or a single pump 5a and a system of manifolds CC with the control of each loop on the valve V of manifold CC (as in the manifold systems of domestic heating, Figure 5) can be used. The control unit 4 can also operate with PID-type adjustment mode (Proportional- Integral-Derivative) or other types which in any case optimize the switching ON or OFF times of pump 5 or 5a as a function of he set goal, i.e., the heat transfer in the desired direction. The optimization of the control system lies in the application of functionalities aiming to quantify the inertia phenomena which are intrinsic to the structure. In other words, not only is there the need to set a threshold for switching ON and switching OFF pump 5, 5a on the difference in temperature Ta and Tb measured by the indoor Tpi and outdoor Tpe probes, but also to analyze the trend of such a difference over time so as to predict the possible change in status of the pump. Through the evolution over time of the input signals, the PID system attempts to switch ON or OFF the operating pump in a predictive manner with respect to the simple threshold condition so as to optimize the desired heat transfer.

The thrust member or pump 5 can vary in nature: a pump with a fixed number of rpm or with three rotation speeds, or it can be provided with an inverter which allows the typical curve thereof to be continuously varied.

In any case, any existing pump on the market is involved such as those for displacing the heat transfer fluid in radiant floor systems, for example.

The pipes 1 can be made of any material (plastic, copper, iron, etc.).

Pipes made of metal material (for example, steel or copper) have increased thermal conductivity and therefore make the overall suggested system more efficient. Pipes made of plastic material (for example, polyethylene or PVC) are less conductive but more lightweight and affordable.

The heat transfer fluid 2 can be water or any other substance. In the areas in which outdoor temperatures below 0°C are expected, there is a need for an additive (for example, glycol), which inhibits the freezing thereof, with varying percentages between 10% and 40% according to the climate zone in which the device is installed. The flow rate of fluid 2 reaches any value and the higher the value, the more effective the system will be, in any case while attempting to compromise between benefits obtained and energy spent for the pumping.

The temperature sensors can be of any type, so long as they are adapted to measure the values expected for each specific application. Increased accuracy of the thermistors is not required for the application at issue, rather the accuracy characterizing thermocouple type probes is sufficient. Various types of thermocouple probes exist, which are sensitive within a given temperature range. T-type probes (constantan copper junction) have a measuring range generally comprised between -200 and 200°C, a range which largely comprises the temperatures related to the phenomenon associated with the invention.

The first results of the walls analyzed through calculation codes (simulations at the finished elements) show a possible variation of the thermal transmittance of the suggested walls from 0.23 to 2.50 W/m ² K.

The simplicity of the technical solution also makes success in terms of effectiveness likely on actual test walls, which will be the object of future experimental tests.

In addition to the configurations described in Figures 2 (coil-shaped) and 4 (round trip extension), each possible path of the pipes 1 in the walls P and between one wall and the next, falls within the scope of the present invention.

By way of example, Figure 6 shows an example of (continuous-exchange) path, in which pipe 1 alternates flowing stretches in the inner wall PI with stretches in the outer wall PE.

Figure 7 shows an example of (spiral) path, in which pipe 1 , in each wall PI and PE, follows a spiral path from the periphery to the center and from the center to the periphery.

Figure 8 shows a system in which the pipes 1 have a varying center distance; such a configuration is particularly useful if the heat exchange is to be accentuated in certain areas of the walls P. Figure 9 shows certain possible arrangements of the adaptive wall P according to the present invention, and in particular, for vertical or horizontal (or inclined) walls. Moreover, various embodiments are provided, in which the intermediate wall PM includes one or more different layers comprising solid layers or insulating layers. Obviously, without prejudice to the principle of the invention, the construction details and the embodiments can widely vary with respect to the above description merely given by way of example, without however departing from the scope of the present invention.