Patent Publication Number: US-2022220797-A1

Title: Dynamic facade system for controlling shading

Description:
The present invention relates to a dynamic facade system for controlling shading. 
     One of the most recent and important research pathways for architecture and construction engineering has been controlling the internal environment of buildings in order to reach a certain level of comfort for the user. Various factors, such as temperature, lighting and humidity, are included in this picture. 
     Control is usually obtained through traditional systems that consume a significant amount of power. Within the context of green buildings aiming for zero emissions, this is no longer sustainable and therefore new paradigms are required. 
     Two main requirements have been identified for the application selected. 
     The system should respect the environment, i.e., from a technical viewpoint, it should require (almost) zero energy to be operated. This would allow the building&#39;s emissions to be limited and its energy efficiency to be increased. 
     The other fundamental requirement is the controllability by the user: the system should be able to respond to user input in order to comply with their needs. This is essential to reach an acceptable individual level of comfort, the conditions of which can differ, depending on the contingent situation, from those programmed. 
     It is immediately clear that these two main requirements are deeply conflicting: the zero-energy paradigm would require a totally passive system, which self-regulates as a function of a given external input and does not respond to the user&#39;s wishes or needs, while controllability entails an active feedback, which naturally requires energy. This opposition is indeed a major obstacle for the practical implementation of intelligent passive facades. 
     The object of the present invention is to provide a dynamic facade system for controlling shading that requires very little energy in order to be operated. 
     Another object is to obtain an adequate level of comfort in different environmental conditions. 
     A further object is to obtain a good level of controllability by the user. 
     In accordance with the present invention, these and other objects still are achieved by a dynamic facade system for controlling shading, characterized in that said facade system comprises a block composed of an outer glass panel, an intermediate framework inside which a series of steel cables are fixed, and an inner framework that incorporates an inner glass panel; said outer glass panel, said intermediate framework and said inner framework being joined to one another: said system comprises modules fixed on said cables; said modules comprise a first outer structure; said first outer structure comprises a frame and at least one first wing; said at least one first wing is movably connected to said frame by means of a first hinge; characterized in that said first hinge is made with a shape memory element with passive configuration. 
     Further features of the invention are described in the dependent claims. 
     The advantages of this solution with respect to prior art solutions are several. 
     With the present solution, an intelligent dynamic facade is obtained, which integrates a solar shading system configured as structures with variable geometry and with shape memory. In the system proposed, sensitivity to sunlight and autonomous drive are combined with the essential features of user controllability and interaction. 
     Drawing its inspiration from nature, just as sunflowers turn their petals in response to sunlight, the designed shading system dynamically adapts its wings to the incoming radiation, regulating their folding/opening configuration. 
     This mechanism is possible due to the use of shape memory materials that possess the unique feature of memorising shapes that can be recovered through the application of external stimuli. 
     The shape memory polymer layer allows completely autonomous passive control of the internal conditions and zero energy drive. Moreover, the integration of an opaque internal layer activated by shape memory alloys (SMA), ensures the possible implementation of the resulting structure in real buildings, balancing comfort, wellbeing and performance (adaptive comfort) and allowing personal control of the living and working environments. 
     The invention allows an increase in the building&#39;s performance both in energy terms and in terms of comfort: while the outer structure allows autonomous regulation with zero energy impact, a further inner structure allows the adaptive user comfort paradigm to be applied. 
     Finally, its modularity allows maintenance costs to be reduced, while also facilitating accessibility. 
     The inner structure acts in parallel and as a complementary and opposing layer with the outer structure. 
     The outer structure makes it possible to obtain a device that is driven automatically based on the external environmental conditions, without the need for any interaction by the user. 
    
    
     
       The features and the advantages of the present invention will be apparent from the detailed description of a practical embodiment thereof, illustrated by way of non-limiting example in the accompanying drawings, wherein: 
         FIG. 1  schematically shows a module of a dynamic facade system for controlling shading, in accordance with the present invention; 
         FIG. 2  schematically shows a drive system of an inner structure of a module of a dynamic facade system for controlling shading, in three different positions, in accordance with the present invention; 
         FIG. 3  schematically shows an electrical circuit of shape memory springs used as hinges of an inner structure of a module of a dynamic facade system for controlling shading, in accordance with the present invention; 
         FIG. 4  schematically shows the possible positions of a module of a dynamic facade system for controlling shading, in accordance with the present invention; 
         FIG. 5  schematically shows a system for containing a plurality of modules of a dynamic facade system for controlling shading, in accordance with the present invention. 
     
    
    
     With reference to the accompanying figures, a dynamic facade system for controlling shading, in accordance with a preferred embodiment of the present invention, is composed of a plurality of modules  10  that comprise a square framework  11  that is used to support an outer structure  12  and an inner structure  13 . 
     The outer structure  12  comprises a frame-shaped square base  15 . The base  15  can be made of plastic materials, wood or metal alloys. 
     A triangular-shaped wing  16  is hinged to each side of the base  15 . The dimension of the wing  16  is such that by moving the four wings  16  toward one another, this forms a pyramid, with a closing angle, for example, of 60°, for aesthetic purposes, although other inclinations are possible. 
     The wings  16  are hinged to the base  15  by means of flexible sheets that form a hinge  20 . Possible other plastic or metal hinges that are free to move can be used to reinforce the connection between the parts. 
     The wings  16  are preferably made of a translucent (partially transparent) plastic material, such as polycarbonate sheets, to prevent excessive darkening of the interiors when they are closed; however, other types of materials and opacities, such as perforated metal or plastic material, can be used, according to need. 
     The hinges  20  composed of flexible rectangular sheets are made with a shape memory element with passive configuration, such as a shape memory polymer (SMP), for example the membrane called Nafion™ N1110. 
     The modules  10  are positioned on the building facade, so that the SMP hinges  20  are illuminated by sunlight and hence heated by it or in any case placed in an environment whose temperature varies as the solar radiation varies. 
     The SMP hinges  20  have been previously trained to allow passage between two configurations, depending on the temperature. Completely open, with an inclination of approximately 90°, relative to the base plane, for low temperatures, i.e. low radiation. Completely closed, with a slope of 60°, at high temperatures, as a consequence of direct solar radiation. 
     The transition temperature of the SMP should be in the range 40-70° C., or more preferably 50-60° C., which represent the normal temperatures reached in facades in daily operating conditions. 
     In an embodiment, the base  15  is a square having a side of around 33 cm. The triangular wings  16  have a height of around 33 cm. 
     The SMP hinges  20 , preferably one per wing  16 , have a dimension, for example, of 100×60 mm. 
     The inner structure  13  is composed of four wings  21  which if placed side-by-side, i.e., in the closed position, form a square with same dimensions as the square framework  11 . 
     The wings  21  are made of an opaque material (through which light radiation cannot pass), for example a black acrylic material such as PMMA, to block sunlight when closed. 
     The wings  21  are fixed to the square framework  11  by means of two hinges  22  per side, formed of springs  23  and  24  produced with an actuator made of shape memory alloy (SMA), for example 0.5 mm wires made of a NiTi alloy. 
     Each hinge  22  is produced by two opposed and adjacent springs  23  and  24 . The spring  23  is wound in one direction and the spring  24  is wound in the opposite direction. 
     The springs  23  and  24  are connected to the wings  21  extending them. In this way a constant tension is created, producing a moment that will be present in both. 
     However, in this case the total moment is approximately zero due to balancing and the wing is held in a position of constant equilibrium that, with reference to the resulting positioning, corresponds to the closed position ( FIG. 2 a   ) where the inner structure prevents the solar radiation from entering. 
     The springs of the shape memory alloy hinges  22  behave as simple resistors and can be driven by electricity or alternatively by controlled temperature changes. 
     The material heats up, exceeds the activation temperature and returns to a previously memorised shape. 
     Therefore, two electrical wires are connected to each spring, one per end, which carry a current generated respectively by a generator  25  and  26  controlled by means of a respective switch  27  and  28 . 
     By operating the switch  27 , the passage of current heats the spring  23  and consequently the wing  21  is positioned in the open position of  FIG. 2   b.    
     By operating the switch  28 , the passage of current heats the spring  24  and consequently the wing  21  is positioned in the retracted position of  FIG. 2   c.    
     To return it once again to the closed position of  FIG. 2 a   , the opposite switch to the one previously operated is operated. 
     The combination of the outer structure  12 , passive, and of the inner structure  13 , activated by the user, allow different operating combinations of the module  10 . Other combinations between the parts are possible based on the purpose of the building, by making slight changes to the configuration of both the passive and controlled drives. 
     Outer structure  12  closed and inner structure  13  open internally, situation of  FIG. 4 a   , which allows the passage of light filtered by the outer structure  12 . 
     Outer structure  12  open and inner structure  13  open internally, situation of  FIG. 4 b   , which allows the passage of light. 
     Outer structure  12  open and inner structure  13  closed, situation of  FIG. 4 c   , which does not allow the passage of light. 
     Outer structure  12  open and inner structure  13  open externally, situation of  FIG. 4 d   , which allows the passage of light. 
     To create a facade by means of the modules  10  a prefabricated block  30  has been produced. 
     The block  30  is composed of an outer glass panel  31 , an intermediate framework  32  inside which a series of steel cables are fixed, preferably arranged vertically, and an inner framework  34  that incorporates an inner glass panel  35 . These are all joined to one another to form a ventilated cavity as the intermediate framework has upper  37  and lower  36  ventilation holes. 
     The side walls of the modules  10  are fixed on the cables  33 . 
     As the block  30  is a natural ventilation system, the air circulates by means of two mechanisms. 
     The wind that flows over the facade generates differences in pressure between the lower ventilation holes  36  and the upper ventilation holes  37 , which brings about movement of the air inside. 
     The air flowing in through the holes  36  is heated by the sun, becoming less dense and thermally floating, rises and is expelled through the upper holes  37 . 
     The block  30  can be made with different outer shapes, such as square, triangular, etc. Other coupling systems of the modules  10  can be used in place of the cables  33 , such as another steel or acrylic substructure. 
     The block  30  can be ventilated in a forced manner, or be completely sealed if the temperatures reached inside allow its operation. 
     To create a facade, in place of the blocks  30  other methods can be used, such as fixing the modules  10  directly to transparent walls, if necessary, avoiding retracted positioning of the inner structure  13 , as in the situations of  FIGS. 4 a    and  4   b.    
     In an alternative and simpler embodiment, the module  10  can be composed solely of the outer structure  12  and hence operate at zero energy consumption. 
     In the embodiment shown, both the outer structure and the inner structure comprise four triangular-shaped wings. These wings can also have other shapes and their number can differ, also differing in number between the outer structure and the inner structure, according to needs. 
     A single wing, or two, four or eight wings can be used, having respective shapes to allow complete closing of the module. In this case, the orientation of the sun&#39;s rays must be taken into account as the number or shape could influence the shade on the contiguous modules. 
     The square module envisaged can also have different geometrical shapes and different dimensions. 
     The hinges  22  are produced, in the example described, with an actuator made of shape memory alloy, but other actuators, such as electric actuators, can be used. 
     Operation of the invention is evident to the person skilled in the art from the description and in particular is as follows. 
     When the facade produced in accordance with the present invention is assembled, the sun&#39;s rays will directly influence opening and partial or complete closing of the wings  16  of the outer structure  12  depending on the features of the hinges  20  and on their temperature. 
     The user will normally maintain the wings  21  in neutral position, but can further regulate the amount of light reached inside the building by controlling operation of the hinges  22  electrically.