Patent Application
20250043571
The present disclosure refers to the sector of construction elements and in particular concerns a self-supporting element for the construction of structures, characterized by low thermal transmittance.
The present disclosure also relates to a method of manufacturing said self-supporting element.
Energy transition represents a global challenge that every country is called to face in order to safeguard the earth's ecosystem.
This process is now essential due to the uncontrolled rise of greenhouse gas emissions, linked to all sectors, by way of example and not as a limitation, residential, industrial and tertiary.
In particular, the residential sector is configured as one of the most energy-consuming and therefore responsible for a substantial portion of the total pollutants and climate-altering substances emitted into the atmosphere. This consumption is largely linked to the inefficient energy design of the building stock.
One of the main causes of energy inefficiencies is the poor design of the building envelope, responsible for substantial heat losses/returns, and consequently increased thermal loads. These loads, to be balanced by appropriate air conditioning systems, are therefore likely to lead to considerable energy consumption.
Today, electricity production on a global scale still relies to a large extent on the exploitation of fossil fuels, and thus non-renewable sources. For this reason, the inefficiency of each element of the building complex can be a non-negligible cause of pollution and climate change.
In this context, there are currently measures aimed at the redevelopment of buildings, in particular of buildings for residential use, which in most cases see as the leading intervention the installation of thermal coats, which are insulation layers aimed at increasing the thermal resistance of the opaque envelope.
On the contrary, for new constructions, a thermal analysis of the building is planned during the design step, aimed at complying with the regulations and minimum requirements in force in relation to energy performance. Despite this, various studies have highlighted the criticalities of current construction techniques. The current critical issues include first and foremost the costs of materials and labor, underlining the need to revisit and reform the processes leading to the construction of a building.
The publicly accessible DM 26/6/2015 provides an example of a regulatory requirement for the construction of buildings in Italy; the details of this DM are therefore not reported here.
Having said this, one can understand the reasons why there is currently great interest in researching new techniques for the design and construction of the building envelope. In this scenario, “Additive Manufacturing”, i.e. the set of techniques for the production of objects starting from computerized 3D models, plays a leading role.
Increasingly stringent regulations pose constraints that represent a challenge also for innovative production techniques such as 3D printing. In detail, among the most complex there is the improvement of thermal performance, which translates into the reduction of thermal transmittance U, representing the indicator of the thermal power exchanged per surface unit and temperature difference, below fixed limit values as the climatic zone varies.
The solutions for reducing the thermal power transmitted through molded walls have so far been inspired by those currently used to improve the performance of the building envelope.
Patent application US2009/0193749A1 relates to a structural element made of fiber-reinforced cementitious material, having a configuration capable of conferring considerable resistance, while being of limited weight. This structural element is presented as a monolithic panel, comprising a pair of frontal components, a pair of side components, a pair of terminal components and a plurality of connection components extending diagonally within the panel between the two frontal components. The connecting components are planar, rectangular-shaped components that may have triangular-shaped notches in order to make the panel lighter. This structural element is obtained by pouring a liquid mixture of fiber-reinforced concrete around a matrix in light insulating material, which, once poured, is left in place in order to make the structure acoustically and thermally insulating.
The scientific article “Mix design and fresh properties for high-performance printing concrete” by TT Le, S. A. Austin, S. Lim, R. A. Buswell, A. G. F. Gibb, T. Thorpe, published in Materials and Structures (2012), Kluwer Academic Publishers, volume 45, pages 1221-1232, concerns a fiber-reinforced cement mixture with workability and extrudability characteristics that make the mixture particularly suitable for use in additive printing processes. A bench made by molding this mixture is also described, the mixture being otherwise usable to make further architectural components, for example cladding and wall panels.
Further documents belonging to the state of the art are the patent application EP3421201A1 and the U.S. Pat. No. 5,644,887.
The purpose of the present disclosure is to describe an element for the construction of structures which allows solving the drawbacks of the known art.
The purpose of the present disclosure is to describe a method for manufacturing the element for the construction of structures capable of overcoming the drawbacks of the known art.
It is a further object of the present invention to describe a self-supporting element for the construction of structures which, while maintaining adequate structural strength, achieves a significant reduction of thermal transmittance, particularly when subjected to a temperature gradient in the direction of its thickness.
It is a further object of the present invention to describe a self-supporting element which has a structure suitable to mitigate the heat transmission through it, said heat transmission being due to conduction and/or convection and/or radiation.
It is a further object of the present invention to obtain an optimization in the energy efficiency of structures such as residential buildings, by means of a simple and economical method for the construction of self-supporting elements, this construction method being moreover flexible so that it can be adapted to different regulatory contexts.
These and further objects are achieved by the element for the construction of structures and by the method for manufacturing said element, which will be described hereinafter in their salient aspects. These aspects can be combined with each other, just as the features in the following claims can be combined with any of the following aspects included in the description.
The invention will now be described in some embodiments with reference to the accompanying Figures. A brief description of the Figures is provided below.
With reference to
The element 1 is configured to be modularly employed together with other elements 1 to create structures including, but not limited to, buildings for residential use. In particular, the element 1, which will be described hereinafter, can be juxtaposed, placed side by side or superimposed on one or more further elements 1, considered individually or in a plurality. In particular, by means of a plurality of elements 1 it is possible to define a wall or a covering of a wall of a structure, in particular of a building. This wall can conveniently comprise a traditional reinforced concrete and/or brick structure.
It is also noted that the element 1 is self-supporting, which means that said element 1 does not require any additional external elements to maintain its shape.
In order to facilitate the understanding of the structure of the invention, the description of the element 1 will refer to a first axis X, a second axis Y orthogonal to the first axis X and a third axis Z, orthogonal both to the first axis X and to the second axis Y. The element 1 is preferably configured to be oriented in such a way that the first axis X represents a vertical axis.
The element 1 is configured to be manufactured by 3D printing or, equivalently, by additive manufacturing.
Additive manufacturing offers countless advantages over traditional manufacturing techniques. The ability to make the complexity of the shapes a value (currently a limitation) and to ensure the uniformity of the materials (leaving their properties unchanged at each point), the reduction in the number of production steps and the lowering of costs are among the privileges of this technology.
In particular, the teachings set forth in the European Patent EP3487673B1 and in the Italian Patent IT102019000006300 may be used for the realisation of element 1, teachings which are incorporated herein for reference.
In detail, as it will become clear from the detailed description that follows, the advantage obtained from the application of a layer of insulation placed externally to element 1 has been studied. The insertion of loose material within the air cavities formed between the layers of cement mortar has been investigated. In detail, these cavities tend to be filled with the aim of creating barriers to heat transfer. Advantageously, the element 1 described herein is specifically configured and designed to be made in a single process through a single material.
The element 1 described herein contributes to improved thermal performances by acting on the geometric configuration of its inner layers.
In the course of the present description, reference will be made to thermal transmittance values. According to the UNI EN ISO 6946 standard, the thermal transmittance U [W/m2K] is given by the reciprocal of the sum of the specific thermal resistances [m2K/W]. In detail, this sum consists of four terms: the internal laminar resistance Rsi and external laminar resistance Rse, the resistance of the non-homogeneous layers Rnh and the resistance referred to the layers of homogeneous material Rh. The internal laminar resistance Rsi and external laminar resistance Rse are equal to the reciprocal of the convective conductance of the air, the resistance referred to the layers of homogeneous material Rh is equal to the ratio between the thickness of the material and its thermal conductivity, while the resistance of the non-homogeneous layers Rnh can be obtained by simulating the behavior of the fluid. The transmittance therefore varies considerably depending on the environmental conditions, which are taken into account by evaluating the internal laminar resistances Rsi and external laminar resistance Rse. These internal laminar resistances Rsi and external laminar resistance Rse are to be evaluated in accordance with what is reported in the UNI EN ISO 6946 standard. If, on the other hand, the heat transfer relative to the wall alone is to be analysed, it is necessary to refer to the thermal conductance C. For non-homogeneous elements, such as for example those with non-uniform thermal properties such as, by way of example and not as a limitation, air cavities, reference must be made to the thermal conductance C of the layer, expressed in W/m2K. The conductance values are reported in the appropriate reference standards including UNI EN ISO 6946 or can be obtained by means of laboratory tests or numerical simulations with finite elements.
Through the conductance C it is therefore possible to disengage from considering the interaction between element 1 and the external conditions (variable depending on the location) and to take into account only the thermal performance of element 1. The values obtained for the conductance C and the transmittance U of element 1, in a particular embodiment characterized by the presence of low-emissivity paints and thermal-insulating paints, are equal to 0.355 W/m2K and 0.335 W/m2K respectively. More generally, the element 1 is configured and specifically adapted to have a thermal conductance C substantially equal to or less than 0.48 W/m2K, more preferably equal to or less than 0.43 W/m2K and even more preferably equal to or less than 0.38 W/m2K and/or to have a thermal transmittance T substantially equal to or less than 0.45 W/m2K, more preferably equal to or less than 0.4 W/m2K and even more preferably equal to or less than 0.35 W/m2 K.
In a specific and non-limiting embodiment, the thermal conductance C differs from the thermal transmittance U due to the liminal air resistances (internal and external). In particular, in this embodiment, the value of the thermal conductance C is slightly higher than that of the thermal transmittance U. By way of non-limiting examples, the Applicant has devised three specific embodiments for the element 1 described herein, wherein U=0.45 W/m2K and C=0.48 W/m2K, or wherein U=0.4 W/m2K and C=0.43 W/m2K, or wherein U=0.35 W/m2K and C=0.38 W/m2K.
The element 1 comprises a first side wall 2 (or first panel 2) and a second side wall 3 (or second panel 3). In the non-limiting embodiment of
The element 1 comprises at least one dividing partition 5 interposed between the first and second side walls 2, 3. The dividing partition 5 has a particular curved profile configured to improve the thermal performance of the element 1, in particular in relation to the thermal convection of the element 1. The curved profile of the dividing partition 5 determines that the distance, measured along the second axis Y, which separates the first and/or second side walls 2, 3 with respect to the dividing partition 5 varies according to the portion of the area of the dividing partition 5 considered.
As can be observed from
In more detail, the specific and non-limiting embodiment of the element 1 of
Although a substantially smooth external face 2e of the first side wall 2 is observed in
Each of the two dividing partitions 5 comprises a first intermediate wall 5a and a second intermediate wall 5b; each of the first and second intermediate walls 5a, 5b comprises a first face and a second face. The second face is substantially opposite to the first face. According to the present invention, the first face is the one oriented towards the left, while the second face is the one oriented towards the right.
Each of the two dividing partitions 5 comprises an upper end portion and a lower end portion. The upper end portion and the lower end portion are substantially aligned along the first axis X.
In a preferred but non-limiting embodiment, the first and the second intermediate walls 5a, 5b are substantially in contact with each other in correspondence of the upper end portion and are substantially separated along the lower end portion. An intermediate portion is present between the upper end portion and the lower end portion; also in this intermediate portion the first and the second intermediate side walls 5a, 5b are separated from each other.
In correspondence of the lower end portion and in correspondence of the intermediate portion there is an air volume 4 between the first and the second intermediate walls 5a, 5b. Within the scope of the present invention, embodiments can also be contemplated wherein the volume defined between the first and the second intermediate walls 5a, 5b is made airtight by means of specific measures. In this case, gases having lower thermal conductivity values than air can be injected into the volume defined between the first and the second intermediate wall 5a, or a vacuum can be created, so that a pressure lower than the atmospheric pressure exists within the volume defined between the first and the second intermediate walls 5a, 5b.
In the non-limiting embodiment of
Preferably, but not limitedly, the curved profile is a profile with sinusoids substantially specular with respect to each other and more generally it is a curved profile without angular points. In particular, computer tools were used to define the optimal curved profile assumed by the first and the second intermediate walls 5a, 5b. These computer tools provide, in one embodiment, the use of genetic algorithms particularly effective in the management of curved profiles without angular points for fluid dynamics analysis.
Furthermore, the maximum inclination of the curved profile with respect to the vertical plane is such that it does not exceed a maximum inclination beyond which the realization of the dividing partition 5 by 3D printing would become critical, said maximum inclination depending on the viscosity of the cement mortar used.
The particular sinusoidal profile conformation of the first and of the second intermediate walls is such that in correspondence of the intermediate portion, the first and the second intermediate walls 5a, 5b each have a convexity facing outwards of the dividing partition 5. In correspondence of the lower end portion, the first and the second intermediate walls 5a, 5b can each have a flexure that identifies a concavity when viewed from the outside of the dividing partition 5.
In
Although the embodiment of the invention illustrated in
In order to ensure the portability of the element 1, a perimeter frame (not shown in the Figures) can be applied to it, which can possibly be removed prior to the installation of the element 1.
In detail, the external face 2e of the first side wall 2 has a layer of thermal-insulating material 6. In particular, said layer of thermal-insulating material 6 comprises thermal-insulating paint. Preferably, but not limitedly, the thermal-insulating paint comprises glassy material, and even more preferably it comprises hollow glass microspheres. The purpose of the thermal-insulating material, in particular of the thermal-insulating paint, is to reduce the heat conduction of the first side wall 2 towards the outside of the element 1.
The inner face 2i of the first side wall 2 has a layer of low-emissivity material 7. In particular, said layer of low-emissivity material 7 comprises low-emissivity paint. Preferably, but not limitedly, the low-emissivity paint comprises an aluminum-based material. The purpose of the low-emissivity material, in particular of the low-emissivity paint, is to reduce the heat radiation of the first side wall 2 towards the inside of the element 1. The layer of low-emissivity material 7 can be present in alternative to the layer of thermal-insulating material 6, or together with the layer of thermal-insulating material 6 as in the case of
In the dividing partition 5 on the left, the first face of the first intermediate wall 5a has a layer of low-emissivity material 7. In particular, this layer of low-emissivity material 7 comprises low-emissivity paint. Preferably, but not limitedly, the low-emissivity paint comprises an aluminum-based material. The purpose of the low-emissivity material, in particular of the low-emissivity paint, is to reduce the heat radiation of the first intermediate wall 5a towards the internal face 2i of the first side wall 2.
In the dividing partition 5 on the left, the second face of the first intermediate wall 5a has a layer of thermal-insulating material 6, preferably comprising thermal-insulating paint. Preferably, but not limitedly, the thermal-insulating paint comprises glassy material, and even more preferably it comprises hollow glass microspheres. The purpose of the thermal-insulating material, in particular of the thermal-insulating paint, is to reduce the heat conduction of the first intermediate wall 5a towards the air volume 4 and towards the second intermediate wall 5b of the dividing partition 5 on the left.
On the first intermediate wall 5a of the dividing partition 5 on the left, the layer of thermal-insulating material 6 and the layer of low-emissivity material 7 can be either both or alternatively present.
In the dividing partition 5 on the left, the first face and the second face of the second intermediate wall 5b each have a layer of thermal-insulating material 6, preferably comprising thermal-insulating paint. Preferably, but not limitedly, the thermal-insulating paint comprises glassy material, and even more preferably it comprises hollow glass microspheres. The purpose of the thermal-insulating material, in particular of the thermal-insulating paint, is to reduce the heat conduction of the second intermediate wall 5b. The layer of thermal-insulating material 6 can be present on both faces of the second intermediate wall 5b or on only one between the first and second faces of the second intermediate wall 5b.
In the dividing partition 5 on the right, the first face and the second face of the first intermediate wall 5a each have a layer of thermal-insulating material 6, preferably comprising thermal-insulating paint. Preferably, but not limitedly, the thermal-insulating paint comprises glassy material, and even more preferably it comprises hollow glass microspheres. The purpose of the thermal-insulating material, in particular of the thermal-insulating paint, is to reduce the heat conduction of the first intermediate wall 5a. The layer of thermal-insulating material 6 can be present on both faces of the first intermediate wall 5a or on only one between the first or second face of the first intermediate wall 5a.
In the dividing partition 5 on the right, the first face of the second intermediate wall 5b has a layer of thermal-insulating material 6, preferably comprising thermal-insulating paint. Preferably, but not limitedly, the thermal-insulating paint comprises glassy material, and even more preferably it comprises hollow glass microspheres. The purpose of the thermal-insulating material, in particular of the thermal-insulating paint, is to reduce the heat conduction of the first intermediate wall 5a towards the air volume 4 and towards the first intermediate wall 5a of the dividing partition 5 on the right.
In the dividing partition 5 on the right, the second face of the second intermediate wall 5b has a layer of low-emissivity material 7. In particular, this layer of low-emissivity material 7 comprises low-emissivity paint. Preferably, but not limitedly, the low-emissivity paint comprises an aluminum-based material. The purpose of the low-emissivity material, in particular of the low-emissivity paint, is to reduce the heat radiation of the second intermediate wall 5b towards the inner face 3i of the second side wall 3.
On the second intermediate wall 5b of the dividing partition 5 on the right, the layer of thermal-insulating material 6 and the layer of low-emissivity material 7 can be either both or alternatively present.
The internal face 3i of the second side wall 3 has a layer of low-emissivity material 7. In particular, this layer of low-emissivity material 7 comprises low-emissivity paint. Preferably, but not limitedly, the low-emissivity paint comprises an aluminum-based material. The purpose of the low-emissivity material, in particular of the low-emissivity paint, is to reduce the heat radiation of the second side wall 3 towards the inside of the element 1.
Finally, the external face 3e of the second side wall 3 has a layer of thermal-insulating material 6. In particular, this layer of thermal-insulating material 6 comprises thermal-insulating paint. Preferably, but not limitedly, the thermal-insulating paint comprises glassy material, and even more preferably it comprises hollow glass microspheres. The purpose of the thermal-insulating material, in particular of the thermal-insulating paint, is to reduce the heat conduction of the second side wall 3 towards the outside of the element 1.
The layer of low-emissivity material 7 can be present as an alternative to the layer of thermal-insulating material 6, or together with the layer of thermal-insulating material 6, as in the case of
Should the element 1 have a further and third dividing partition 5 interposed between the first and the second dividing partition 5 on the left and on the right respectively, the first and the second intermediate walls 5a, 5b of said third dividing partition 5 could each have a layer of thermal-insulating material 6 on the first and/or second face, or be devoid of additional layers.
The application of low-emissivity and thermal-insulating paints can include the execution of painting steps after the construction of the structural components of element 1. The application of paints can involve faces of the first side wall 2 and/or of the second side wall 3 and/or of the dividing partitions 5 in their entirety, or alternatively only portions of these faces.
In order to provide sufficient structural strength to the invention, each of the first and the second side walls 2a, 2b and of the first and the second intermediate walls 5a, 5b of the dividing partition 5 is made of cementitious material or more generally of any mortar having extrudability and/or 3D printability properties. In particular, said cementitious material comprises cement mortar.
In a preferred embodiment, the mortar comprises a cementitious composition which reproduces the teachings of the European patent EP3487673B1 in the name of the Applicant Etesias Srl, in particular the teachings referred to in paragraphs [0032] to [0045].
Profitably, the cement composition comprises:
The cementitious composition may also comprise further elements, in particular those in the following list:
More precisely, the weight ratio between water and cement is between 0.3 and 0.45 or the water/cement equivalent ratio is between 0.29 and 0.49; the expression cement equivalent means that part of the cement is replaced by type II additions according to the UNI EN 206-1:2006 standard in a percentage between 1% and 3% by weight with respect to the total weight of the composition.
In order to ensure surface homogeneity, the maximum diameter of the at least one inert aggregate is less than 13.5 mm, preferably less than 13 mm, more preferably less than 12.5 mm.
The Applicant observes that among the types of cement that can be used in the cementitious composition, the cement is preferably selected from a group of cements belonging to types I, II, III, IV, V, established by the EN 197-1 standard. This standard is implemented at a national level by the UNI EN 197/1 standard; preferably the cement is selected from those belonging to types I, II, III, IV and V and having resistance classes 42.5R and 52.5R according to the UNI EN 197/1 standard; more preferably, the cement is selected from those belonging to the CEM II/AL (or A-LL) 42.5R and CEM II/AL (or A-LL) 52.5R classes; even more preferably, the cement is selected from those belonging to the CEM II/AL (or A-LL) 42.5R class according to the UNI EN 197/1 standard. This ensures compliance with the standards and optimal resistance of the manufactured product.
When present, the inert aggregate is preferably selected from fine aggregates, fillers and mixtures thereof. The filler is selected from quartz sand, silica sand and limestone filler. The inert aggregate comprises a mixture of sand and quartz sand and/or limestone filler.
When present, the polymeric fiber preferably comprises at least one of: a polyolefin fiber, preferably polypropylene (PP); a polyvinyl alcohol (PVA) fiber; a polyester fiber; an aliphatic polyamide fiber (Nylon).
When present, the superplasticizing agent can be selected from optionally modified polymers polycarboxylic polyethers, naphthalenesulfonic, polyphosphonic, acrylic, propylene glycols and mixtures thereof. Preferably, the superplasticizing agent is a modified polycarboxylic polyether polymer.
In a further embodiment, the cement mortar comprises cement (by way of example and not as a limitation, Portland Clinker) and a stone aggregate, preferably fine-grained. This stone aggregate, in a non-limiting way, may include in particular sand and/or blast-furnace slag and/or shale and/or limestone and/or fly ash. Depending on the composition chosen, the cement mortar can comprise between about 3 kg of cement per dm3 of stone aggregate to about 6 kg per dm3 of stone aggregate.
In particular, it can therefore be asserted that, on the whole, the materials for making element 1 are the following:
In a preferred but non-limiting embodiment, the mortar is produced starting from a dry premixed powder consisting of selected sands with the addition of water. The compound (obtained by respecting appropriate proportions, in particular preferably those proposed above) has mechanical properties that are useful for self-supporting during a 3D printing step.
In an initial step (block 1000,
Account is also taken of a limit value Ulim of thermal transmittance U that the element 1 must have due to the constructional constraints and/or the environmental conditions of application. This limit value Ulim of thermal transmittance is a maximum limit value. The assessment of the thermal transmittance of element 1 corresponds to block 1002 of
On the basis of the geometric and constructional constraints and on the basis of the limit value Ulim of thermal transmittance, the internal geometry (block 1003) is modelled.
Once the basic internal modelling has been defined, if the thermal transmittance U is lower than the limit value Ulim (block 1004, output Yes) there is no need to adopt further details on element 1; the process therefore ends (block 1009,
Otherwise, if the thermal transmittance U is greater than Ulim (block 1004, output No), first of all an application (block 1005,
In detail, the thermal-insulating material can be applied on at least one between the first and the second side walls 2, 3, in particular on at least one external face 2e, 3e of at least one between the first and the second side walls 2, 3 and/or at least on the internal faces of the first and/or second wall 5a, 5b of the dividing partition.
With specific reference to the embodiment of the element 1 illustrated in
At this point, the process includes a new check (block 1006,
The application of the layer 7 of low-emissivity material takes place on at least one between the first and the second side walls 2, 3, and in particular on an internal face 2i, 3i of at least one between the first and the second side walls 2, 3. In the specific embodiment of
Once the above application has been completed, a new check is carried out (block 1008,
Preferably, but not limitedly, the low-emissivity paint and/or the thermal-insulating paint is applied by using an airbrush, or in any case, more generally, by using a spray technique.
It is noted, in particular, that before the installation of the element 1 it is preferable to wait for a predetermined time to allow the previously sprayed paint to dry. This drying time, preferably longer than ten minutes, is generally defined by the paint manufacturer, on the basis of the characteristics and/or composition and/or according to the characteristics (at least porosity and/or type) of the material on which said paint is sprayed.
In any case, it is noted that before proceeding with the spraying of the paint on the cement mortar it is preferable to wait a predetermined time for said cement mortar to reach a predetermined level of drying.
As can be seen in the diagram of
As illustrated in
The simulations performed then revealed that the thermal flux [W/m2] established within element 1 with a temperature differential ΔT=10° C. along the first axis X has an average value substantially equal to (or less than) 3.35 W/m2. This is a significantly lower thermal flux value than the one that would be obtained with reference structures without internal cavities, showing a high efficiency of the element 1 according to the invention in reducing thermal transmission.
The prototyping of the 3D model of element 1 is done using CAD software. The geometry thus created is imported into a software for thermo-fluid dynamics simulation (CFD), through which the thermal performance of element 1 is evaluated by defining appropriate boundary conditions.
An experimental evaluation was carried out in the thermal analysis laboratory of insulating materials (IMATlab) of the Federico II University of Naples, using the NETZSCH Guarded Hot Plate (GHP) 456 Titan® instrumentation, through which a thermal conductivity value of the material (k) of 1.05 W/mK was obtained.
The non-limiting prototype of the element 1 examined during the experimental evaluation involves the application of two low-emissivity paint layers for the mitigation of thermal radiation phenomena. In detail, this paint guarantees a reduction in the emissivity of the cavity walls with consequent reduction of the thermal power transferred by radiation.
Low-emissivity paints capable of ensuring an emissivity value of 0.2 in the infrared band are currently on the market.
Since the thermal power released by a surface is proportional to its emissivity, the adoption of these paints (based on aluminum powders) by virtue of the reduced emissivity leads to a reduction of the overall thermal radiation emitted by the element 1.
The geometry optimization step is preparatory to the construction of the prototype. In detail, the optimization process consists in parameterizing the model according to the geometric constraints set during the design step. Each geometric variable can assume discrete values within a suitably defined range in relation to the identified geometric constraints.
The main geometric variables that influence the objective function to be minimized, represented by the thermal transmittance U, are the overall thickness along the second axis Y of the element 1 and the thickness of each of the layers of cement mortar making up the first and the second side walls 2, 3 and the first and second side walls 5a, 5b of each of the dividing partitions 5 present in the element 1.
It has been experimentally verified how the stability of the cement mortar in the deposition step is influenced by this parameter. In detail, the greatest stability is achieved if a 0.04 m diameter nozzle is used to carry out the aforementioned 3D printing. In general, optimal diameters for the 3D printing of said cement mortar are substantially between 0.03 m and 0.05 m, more preferably between 0.035 m and 0.045 m.
In a preferred and non-limiting embodiment, the maximum extension along the first axis X and along the third axis Z of the element 1 is 3 m; along the second axis Y, said maximum extension is preferably equal to 0.6 m. Although there are no theoretical limits of the minimum extension of the element 1 along the first axis X and along the third axis Z, in one embodiment the minimum extension of the element 1 along the second axis Y is 0.4 m. Preferably, but not limitedly, the maximum overhang is equal to 15°. Furthermore, in a non-limiting embodiment, each of the walls made of cementitious material has a thickness, measured along the second axis Y, substantially comprised between 4 and 6 cm.
The advantages of the element 1, object of the present disclosure, are clear in the light of the preceding description. Said element 1 is designed to optimize the energy efficiency of structures, in particular residential buildings, and is simply and economically made by means of 3D printing. The element 1 adopts a particular structural conformation which simultaneously optimizes a reduction in thermal conduction, thermal convection and thermal radiation. The element 1 can also be economically produced on a large scale and can be adapted through the use of low-emissivity and thermal-insulating paints to different regulations in relation to the climatic context of the structure. In particular, the reduction of conduction, convection and radiation is achieved by means of a high-strength element 1.
The element 1 described herein is also compatible to be placed side by side, optionally juxtaposed, to at least one other element 1, or to more than one element 1, along the direction indicated by the axis Y to further reduce thermal transmission.
The invention is not limited to the embodiments illustrated in the Figures. For this reason, the reference signs in the claims should not be understood in a limiting way. In fact, the reference signs are provided for the sole purpose of increasing the intelligibility of the claims.
Finally, it is clear that additions, modifications or variants, which are obvious to a person skilled in the art, may be applied to the element and method described herein, without thereby falling outside the scope of protection provided by the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102021000028745 | Nov 2021 | IT | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2022/060826 | 11/10/2022 | WO |
