ES2455415A1 - Ceramic coating system with evapotranspiration cooling (Machine-translation by Google Translate, not legally binding) - Google Patents

Abstract

The object of the invention is an exterior cladding system for buildings and constructions by means of pieces of porous ceramic material or the like called "facade-botijo". The system can be applied as direct cladding or as an external sheet in "ventilated faºade" solutions. Compared to traditional solutions of "passive" coatings in buildings, the system incorporates the possibility of causing a cooling in its surface thanks to the evapotranspiration induced by the contribution of water through a network of alveoli inside the pieces. Its main application is the thermal control of the envelope in warm climates and the cooling capacity of the air in the interior spaces of buildings. (Machine-translation by Google Translate, not legally binding)

Description

Ceramic coating system with evapotranspiration cooling

Object of the invention
The object of the invention is framed in the area of architecture, construction, the ceramic sector, bioclimatic architecture, eco-construction, biomphmesis and energy efficiency of buildings. It is an exterior cladding system for building and construction enclosures by cladding pieces of porous ceramic material or similar characteristics, with surface cooling capacity by evapotranspiration, also known as "botijo effect". It is especially suitable for locations with hot and dry climates where there is a high energy demand for the cooling of buildings or is intended to mitigate the "heat island" effect in an urban environment.

State of the art

Building cladding solutions using natural and artificial stone plates, ceramics and stoneware are common construction techniques
contemporary and widely spread throughout the world. According to the current state of the art; H. Schmitl, A. Heene. "Treaty of construction". 7th extended edition. Ed. Gustavo Gilí. Barcelona 2002. Page 231-236, according to their form of placement, we find two ways of alternative placement of the plates on the facades: by direct fixation (using a continuous layer of mortar or similar), or with indirect fixation, by executing a camera air enters the plates and the building, using a technique called "ventilated facade".

The constructive solutions of discontinuous coatings using façade plates provided by the Spanish building regulations include a wide range of possible construction solutions, which are defined in the following sections of the Catalog of Construction Elements; Ministry of Development. "Catalog of Constructive Elements" CEC. Document recognized for the Technical Building Code. March.2010 version. www.codigotecnico.org., CEC .:

•

4.2.6 Factory with discontinuous coating, without chamber or with non-ventilated air chamber, insulation inside.

•

4.2.7 Factory with discontinuous coating, with ventilated air chamber, interior insulation

•

4.2.8. Factory with discontinuous coating, with ventilated air chamber, exterior insulation.

•

4.2.10 Ventilated light facade.

Conventional facades and envelopes of buildings, such as those provided for in the CEC, traditionally maintain a passive character or behavior against the regulation of the interior temperature of buildings. Its insulation remains constant over time, and the heat flux occurs, essentially, depending on the thermal jump between both sides.

Evapotranspiration is a phenomenon that is defined as the loss of moisture from a surface or soil, which is produced by direct evaporation along with the loss of water by vegetation transpiration. This phenomenon has been taken into account as a bioclimatic technical potential for building conditioning, giving rise to constructive solutions such as the green roofs and the recently developed vegetable facades. The evapotranspiration of the vegetation cover of the building thus acts as an effective regulator of temperature and humidity on the surface and even of the immediate surroundings of the buildings.

Among the multiple scientific references located on these applications of plant facades or "vertical nature"; Terapia Urbana, Spin-off of the University of Seville, has specialized in the development of plant facade solutions. ht! p: /lwww.terapiaurbana.es/. We can highlight the one described in the article "Thermal behavior of a natural cladding system on facade walls ':' CY Cheng, Ken KS Cheung, LM Chu," Thermal performance of a vegetated cladding system on facade walls ", Building and Envíronment, Volume 45, Issue 8, August 2010, Pages 1779-1787, ISSN 03601323,10.1 016 / j.buildenv.201 0.02.005 (ht! P: /lwww.sciencedirec! .Com / science / articlel pi / S0360132310000545) In it It stands out as a practical conclusion that "the lining of vegetation reduces the internal temperature and the delay in the transfer of solar heat, which therefore reduces the energy consumption in air conditioning compared to an exterior enclosure of the bare concrete building". Similarly, it follows that the cooling effect is closely associated with the area covered by living plants and the moisture of the crop support.

However, the solutions of roofs and plant facades have significant investment costs, and especially maintenance costs, since their correct functioning depends precisely on the life of the plant species incorporated into the enclosure, as described in the referenced bibliography.

Ceramic, as a construction material used in coatings, has an interesting property such as the partial absorption of moisture through its surface (when it does not have waterproof, glazed, etc. finishes). This has traditionally been used as an environmental conditioning resource, whose most immediate example is the custom of watering the (ceramic) floor of the courtyards in Andalusia to cool the environment during the summer. Another example of taking advantage of this property of ceramics is found in the physical principle called "botijo effect"; In the wikipedia article on the term "botijo" you can find the mathematical expression that describes the physical process of the thermodynamic operation of the botijo: hUp: lles.wikipedia.org/wiki/Botijo#F.C3.ADsica.2C_qu.C3.ADmica -y_matem.C3.A 1 tica_del_botijo. There are several ceramic-based products on the market for use as exterior discontinuous cladding in buildings, either as tiles for direct application or by plates for placement as a ventilated facade. According to the catalog of ceramic materials of HYSPALlT: "Discontinuous coatings of ceramic elements are thin plates made of clays and / or other inorganic raw materials generally used as floor and facade cladding, molded by extrusion, by pressing or other procedures at room temperature, then dried and then cooked at temperatures sufficient to develop the necessary properties. " According to this publication, within the ceramic materials applicable on facades, depending on their absorption to water, the so-called "terracotta" are placed above 6%. This type of material will be the one that interests us from the point of view of the invention, being the one with the greatest capacity for water absorption (L. Vega Catalán et al "Catalog of Ceramic Solutions for compliance with the Technical Building Code" HYSPALlT and IETcc. 2008. Pages 38-40)

An interesting example of the application of artificially dampened ceramics as a passive environmental control technique was the one used in the construction of the Pavilion of Spain in the international exhibition of Zaragoza 2008. The architect Patxi Mangado, with the advice of the National Center for Renewable Energies (CENER ), he projected a "forest" of columns formed by extruded cylindrical ceramic pieces through whose interior the water circulated and, when evaporating on its surface, cooled the space of the porch of the building.

Published patents of interest:

ES8606940 A1, ADIABATIC COOLING PROCESS FOR THE CONDITIONING OF SPECIALLY LARGE BUILDINGS ES1063712 U (16.11.2006), BIOCLlMATIC PREFABRICATED BASEMENT WALL FOR BUILDING CN101654937 (A), COOLlNTRUCTING PERFORMANCE AND BUILDING METROCHOURDING, BUILDING METROPEDING, BUILDINGS MODULE VENTILATION OUTERWALL JP2008231717 (A), COOLlNG STRUCTURE OF EXTERIOR WALL JP2008163654 (A), COOLlNG UNIT AND COOLlNG STRUCTURE OF WALL SURFACE OR ROOF SURFACE USING IT JP2003328462 (A), STRUCTURE WINDOW COURAGE (A), WALL SURFACE COOLlNG TILE AND WALL SURFACE STRUCTURE JP2005037007 (A), BUILDING COOLlNG SYSTEM CN102220788 (A), METHOD OF BUILDING STRUCTURE USING ATOMIZED COOLlNG EXTERNAL WALL DE102008013196 (A1), COOLLESES FOLESD (AS), BUOLDES FOLKESAC (A) WATER STORAGE MEDIUM WITH BRUSH-LlKE, CAPILLARY EVAPORATION SURFACE COMBINES JP2009121059 (A), METHOD AND STRUCTURE FOR COOLlNG BUILD ING JP2007271121 (A), HOT ENVIRONMENT REDUCING DEVICE JP9279707 (A), COOLlNG WALL

Several documents have been found describing coating systems with evaporation cooling, referred to in the previous list, highlighting the documents "STRUCTURE OF COOLlNG WALL -JP2003328462" and "BUILDING COOLlNG SYSTEM -JP2005037007" that use porous ceramic materials and the "METHOD OF BUILDING STRUCTURE USING ATOMIZED COOLlNG EXTERNAL WALL-CN102220788 (A) ", which provides cooling by means of ceramic modules with atomized water injection with induction of an upward air flow inside. As well as two systems or 'solutions of stone or ceramic coverings that perform cooling functions by artificially induced surface evaporation: "WALL SURFACE COOLlNG TILE AND WALL SURFACE STRUCTURE -JP2009079469 (A)" and "EXTERNAL FACING MATERIAL WITH EVAPORATIVE COOLlNG FUNCTION JP2011157735 ) "

Description of the figures

Figure 1.-Psychrometric diagram indicating the processes of transformation of the air in the air chamber, and the outside air, in summer conditions, where:

B-Air on saturated moisture surface (Te, Hs = 100%)

B'-Air in the chamber (T s, He ·)

AB-Adiabatic saturation of outdoor air

AB'-Sensitive cooling of the air in the chamber

-

t.T = Thermal jump by cooling

Figure 2. Process of surface cooling by evapotranspiration. Horizontal section type by socket (1) of proposed ceramic piece, descriptive of the process of water supply through the inner walls of the socket (2), the saturation of the piece of porous material (3), the moisture outflow to the surface and its surface evaporation (4) and the water-impermeable finish or layer of the inner face (5).

Figures 3 and 4. Schemes of possible joints between pieces of different courses. Solutions for the continuity of the downward flow of water (1) by means of bushings (Fig. 3) or tongue and groove (Fig. 4). Plant and vertical section along the axis of the alveoli. The measure "R" or free space between courses will be 6 ± 2mm. In Fig. 3, the overlap between the bushing or connecting piece (6) and the ceramic piece "S" will be between 5 and 20 mm, including a sealing element (7) between the workpiece and the bushing. In Fig. 4 the depths "P" and "M" of depth and projection of the tongue and groove will be between 5 and 1 O mm, avoiding that after assembly there is
a direct contact between pieces.

Figure 5.-Generic schemes (horizontal sections) of the profile of the ceramic pieces "type" proposed. Representation of the type section of the pieces with inner diameter "D" socket, depth of "H", material thickness "T". Three design proposals are presented (corrugated, edged and in honeycomb), with two alternatives of finishing: smooth face inside, suitable for direct mounting, and fluted finish on both sides for indirect mounting. The number of cells per piece represented in approximate, always being greater

or same as one. The general dimensions of the pieces (height, width and edge "C") -, the number of contained cells and the distance between them are variable. The profile or design of the vertical longitudinal edge for adjustment between parts is indicative.

Description of the invention The invention consists of a novel coating solution for buildings

or constructions by means of a cladding of ceramic pieces or other porous material similar to which a controlled humidity contribution is made thanks to a system of internal cells or channels through which water is circulated by gravity. When the water absorbed by the pieces evaporates on its outer surface, a superficial cooling occurs that helps reduce the surface temperature of the enclosure, and therefore, inside the building.

The solution consists of traditional building elements and materials. For its operation or activation of cooling, it only requires a certain amount of water for evaporation, which may come from rainwater recovery or recycling systems within the same building, thus reducing the demand for drinking water for its operation.

The system can be applied to the enclosures of buildings and constructions as direct cladding, by means of fixing techniques applicable to others

placated stone or ceramic. Likewise, the system can be arranged in an indirect assembly as an outer sheet in ventilated facade construction solutions.

The cooling of the surface can be used to reduce the outside temperature of the enclosure, and therefore, the heat gain per transmission.

Likewise, applied as an exterior cladding or sheet in "ventilated façade" solutions, it can be used as a cooling technique for the chamber air in the trasdos, which, in turn, can be used as ventilation air for the interior spaces of the building, passively cooled, natural and free.

As an alternative to the "vegetal facades" or "nature", it dispenses with the technical inconveniences associated with the maintenance of the species and the substrate, although it retains the main advantage such as a hygrothermal regulation on its surface thanks to its surface wetting system.

Compared to traditional ventilated façade systems, at a similar material cost, it offers the ability to act on the building's climate control, and its surface temperature can vary thanks to controlled evaporation, and even cool the chamber air for contribution as pre-cooled ventilation air, without cooling energy consumption.

The invention consists of a coating or finishing system for buildings or constructions formed by a cladding of special ceramic pieces that have continuous longitudinal alveoli or canaliculi that are mounted by means of mechanical type anchors or chemical adhesives to an independent structural support.

Water is circulated inside the alveoli from a supply system in its upper level, which flows by gravity adhered to the interior walls and saturating the entire surface of the ceramic pieces with moisture.

The pieces are connected to each other by means of watertight flexible bushings, connecting lugs or similar parts so that the continuity of the alveoli is guaranteed, and therefore, the water supply to all the pieces along the facade section.

At the base of the facade there is a collection of water from the possible drip that occurs when the flow of water provided by the humidification system of the pieces is greater than the ability to instantly evaporate the surface of the facade, and by Therefore, the pieces become saturated with moisture and excess water is expelled from the inside of the alveoli. However, the humidification system will be regulated to balance the water supply with the evaporation rate at all times in order to minimize the excess water evacuated by the alveoli.

The design of the ceramic pieces is intended to favor the evaporation of water on the outer surface. To this end, it has a vertical stretch finish, with protrusions between 7 and 30 mm, so that the perimeter developed doubles approximately the length of the piece, and therefore, the evaporation surface compared to a piece with flat faces .

The pieces also have alveoli or canaliculi with a free interior section between 10 and 20 mm, and a wall thickness "T" between 5 and 1 O mm to favor a homogeneous water absorption in the whole of the piece and optimize evaporation of water and material consumption.

The manufacturing material of the cladding pieces can be of ceramic or concrete type, although its main characteristic, apart from its mechanical properties, will be its ability to absorb water or porosity.

Among the suitable materials to consider, clays are proposed for those used in the manufacture of pottery and handicraft pots (vessels, pots, etc.), since it is precisely the phenomenon of evaporative surface cooling that occurs in the botijo that inspires the Design of this cooling finish for buildings.

The water absorption E (%) will be above 6%. In places with a risk of frost, values close to this limit will be adopted.

The exterior surface finish of the pieces must be free of treatments, films or finishing paints that close the pores of the ceramic, thus preventing the evaporation of the water provided from inside the pieces.

The inner face of the pieces must have a waterproof finish, either by surface finishing treatments, primers, glazing, etc., of the piece itself, or by the provision of a continuous barrier against water, such as an auxiliary metal support on which to fix the pieces (for example, corrugated galvanized or folded "pegasus" type). The objective of this requirement is to avoid the contribution of moisture towards the inner layers of the building enclosure, or, where appropriate, towards the air chamber.

The water supply to the set is produced by a specific water supply installation consisting of pipes, valves, pumps, tanks and automatic control devices that regulate the operation of the system according to the environmental variables of the interior space, the weather, the radiation solar incident on the facades and the degree of humidity of the facade.

The water supply is done continuously from the top of the enclosure by means of a series of micro-diffusers or irrigation nozzles introduced or connected to each socket.

These nozzles or micro-diffusers are supplied from a branch or collector that will run over the roof or contour of the roof of the building or construction along the entire ceramic facade. The supply manifold and the nozzles will be regulated to match the outflows in each socket, so that there is a homogeneous supply of water to the surface of each facade cloth, depending on its height, sun exposure, wind , etc. The collector or collectors of water supply of the façade or set of ceramic facades in the building or construction will have a sufficient supply of water under pressure.

In order to minimize the consumption of drinking water, it is proposed to use rainwater filtered from impurities, or where appropriate, decalcified drinking water, since this reduces the contribution of salts to the ceramics that could end up saturating the capillary network of the material, thus reducing the surface evaporation capacity, and the appearance of pathologies due to saline deposits (efflorescence, etc.).

As mentioned above, a collection of water must be provided at the base of the facade by means of a gutter or gutter on the pavement under the facade. The leftover water thus collected, like that from the rainwater incident on the facades, can be reused to replenish the reservoir from which to supply the supply network proposed for the system.

Functioning.

The surface cooling capacity of this facade system is especially indicated for buildings or constructions in hot climates, where the summer regime prevails, and the design of the facades prevails the massif in front of the surface of holes or windows. The system would be activated during periods of maximum sunshine and outside temperature to optimize its operation. The rest of the time, during the night period or cold seasons will remain deactivated.

The effect of surface evaporation benefits on the one hand inside the building by lowering its surface temperature, but it also affects the environment of the constructions, since the contribution of additional humidity contributes to lowering the temperature around it, and thus reducing the "heat island" effect.

Application.

The described finishing system can be incorporated into the building enclosure in two ways:

The first one or "direct fixation" consists of a solution of direct fixation to the facade, either by mechanical anchors or even epoxy-type adhesives, to the outer sheet of the enclosure factory, as would be done with a conventional solution of Direct cladding with stone pieces, ceramic tiles, etc. In this case the cooling of the surface by evaporation, when the environmental conditions demand it, would lower the temperature of the outer face. The cooling is thus transmitted directly by "transmission" to the inner layers of the enclosure, which would reduce the heat gain through the facade in summer conditions.

The second mounting option would be that of "indirect fixation", consisting of the use of a substructure or auxiliary support to which it is fixed by means of mechanical anchors or even adhesives of expoxidic type, in turn fixed to the inner layers of the building enclosure or construction, creating a ventilated air chamber between both elements (as established in OS HS 1, of the Technical Building Code, a ventilated air chamber has a thickness

2: 3 cm and S 10 cm, a system for collecting and evacuating water and ventilation openings with a width> 5 mm distributed 50% between the top and bottom of a cloth between floors. A continuous air chamber of approximately 3 to 10 cm thick can be arranged between the ceramic pieces and the inner sheet of the enclosure. In the base and the coronation of the facade, adjustable openings are arranged by means of grilles or gates in its upper and lower part to regulate the entry and flow of air inside the chamber. Finally, they are arranged in the inner sheet of the enclosure towards air intakes towards the different spaces or mechanical ventilation systems of the building.

Thanks to the cooling process by the surface evaporation of the outer sheet, the air contained in the chamber, upon reaching thermal equilibrium, will be cooled from the dry temperature of the outer environment to the wet bulb temperature at which the outer sheet will be, but without increasing its moisture content, by means of a "sensitive cooling" psychrometric process (Process AB 'in FIG. 1).

The air thus cooled can be passed into the building through the intake openings of the chamber as ventilation or renewal air, but pre-cooled naturally and free of charge (-b.T in the figure).

This technique can reduce or even cancel the ventilation load in summer since the air supplied from the outside, and cooled through the chamber, reaches the interior at a temperature close to that of comfort in the summer regime, which is especially interesting in tertiary buildings with important ventilation requirements.

If sufficiently wide air chambers are available, from 10 cm thick, convection phenomena begin to appear inside the chamber. During the operation of the surface cooling of the façade, the air cooled in the chamber would be located at the bottom of it, having a higher density. This is especially interesting in the application of this system as a coating for bioclimatic elements such as the ventilation towers used for passive environmental conditioning of the interior of buildings. The ceramic coating would serve to enhance the effect of falling and cooling the air on the breeze pick-up towers or ventilation towers. Figure 1.

Embodiment of the invention

The ceramic facade system with evaporation cooling has been successfully used in an example of the construction of a low-cost self-sufficient housing.

The system was used, in particular, as a coating for the exterior walls of chimneys or ventilation towers. Through this technique the duct or air intake channel of each tower, located on the north facade of the house, was coated. The 30 x 90 x 30 cm floor covering and about

400 cm high, in the central hours of the day, managed to lower the air inlet temperature through each tower from 28 ° to 22 ° C.

For the design of the pieces, a honeycomb toothed profile was used, with alveoli of a free internal diameter of about 12 mm, and a thickness between 6 and 10 5 mm. The raw material was white clay used in pottery, being prepared by the technique of "colage",

The type of assembly used in this case was of the type "indirect fixation", using a support of galvanized sheet folded type "pegasus", to which ceramic pieces were mechanically fixed with a finish coinciding with

10 that of the metal support, to allow its coupling and fitting.

The pieces were fixed to the support by means of two self-drilling screws and head with a washer sealed to the metal support that formed the drawer or vertical air intake duct of the ventilation chimney. To interconnect the alveoli between pieces, PEX pipe bushings were used

15 of 12mm sealed with single-component adhesive putty type "Sikaflex" at the base of the alveoli of each piece, and simply embedded in the upper mouth of the corresponding socket of the lower part.

The water supply was made through a plastic pipe network and an upper collector in each tower with a terminal comb with micro-diffusers of

20 irrigation that were introduced in each socket. At the base of the wall, a gutter was arranged for the collection of the excess water, evacuated to the water purification and reuse system of the prototype. The contribution was made through a branch of the building's irrigation system, which was programmed to activate intermittently during the central hours of the day.

Claims (6)

one.

2.

3.

Four.

Ceramic coating system with cooling by
evapotranspiration or "botijo effect" characterized by being formed by
a) a cladding of ceramic pieces saturated with alveoli longitudinal and fixed by chemical or mechanical anchors to an independent structural support, b) a water supply system that circulates water by gravity through the inner walls of the alveoli and, c) horizontal joints or joints between parts by means of watertight flexible bushings or similar pieces that vertically interconnect the alveoli of different pieces with each other along the façade, one of water collection at the base of the facade section by means of a gutter and optionally, an air chamber between the cladding and the inner leaf of the building enclosure. Ceramic facade system according to claim characterized in that the ceramic pieces have an outer surface of vertical grooves with protrusions, in the form of a fret, with a thickness between 5 and 15 mm, so that the perimeter developed approximately duplicates the length of the piece, and Alveoli with a free inner section between 10 and 20 mm free inner diameter to favor the evaporation of water and the maximum use of the material. Ceramic facade system according to previous claims characterized in that the ceramic pieces that compose it are formed by ceramic type material, with a water absorption, greater than 10% and a surface finish on the outer face without treatments, films or paintings that close the Ceramic pores and prevent evaporation of the water provided to the piece through the alveoli. Ceramic facade system according to previous claims characterized in that the ceramic pieces that comprise it have their inner face waterproofed, or they are fixed to a continuous auxiliary waterproof support preferably metallic.

5.

System from facade ceramics according claims previous

characterized by having a water supply facility

at the top of the facade using micro-diffusers or nozzles

irrigation

in each socket, and by its bottom pickup and reuse in he

   5

system, formed by pipes, valves, deposits, bombs Y

control elements, which

automatically activate in function of

weather conditions,

of solar radiation incident on the facade and

the degree of humidity of the ceramic.

10

6. System from facade ceramics according claims previous

characterized

by provide, optionally from a camera from air

continuous between 3 and 10 cm thick between the pieces

ceramics and the inner sheet of the enclosure, openings adjustable by

grilles or gates at the top and bottom and air intakes towards

fifteen

The interior space of the building.

7.

Ceramic facade system according to claim 6, characterized in that

the interior finish of the piece and the possible continuous auxiliary support of

Metallic type are striated to maximize the exchange surface

twenty

thermal with the chamber air.