DE202020004997U1 - Layer package for the reflection of radiant heat - Google Patents

Abstract

Layer package for the thermal protection of rooms with dominant radiant heat input and without heat-effective convection processes in buildings or vehicles and ships on the external components such as walls, floors or ceilings consisting from the outside inwards from Requirements such as fire, moisture, noise, weather, aesthetics met, b) optionally an adjacent anti-condensate insulation [10] c) in front of this usually two-layer, heat-reflecting foils separated by grid elements [4], [7] [ 6], [9] with the respective air gap [5], [8], d) a visual, protective or functional cladding as a thermal barrier.

Description

The insulation measures specified for buildings in Germany do not meet the expectations placed on them. In a focus article [focus20], the verdict is relentless and the talk is of “the energy transition becomes a billion-dollar grave”. What began around 30 years ago with the development of the passive house standard no longer meets today's requirements and leads to disadvantages, which, however, are hardly reported. With increasingly thick insulation layers, the hoped-for effect cannot occur for mathematical-physical reasons [Meier09, Meier10]. For 30 years, however, insulation practice has manifested itself in such a way that, apart from improved system technology, there is apparently no other way than thick insulation. In [Beuth15], reference is made to the maximum achievable insulation effect, according to which "in the foreseeable future the heat transfer coefficient (U-value) of the components will not ^{drop below 0.08 to 0.10 W / m 2} K as standard ...". In fact, with reflection of the radiant heat for the entire building envelope, the equivalent heat transfer value below 0.06 W / (m ² K) can be achieved.

• Was reflektiert ist, braucht nicht gedämmt zu werden.

In [Horn 12, 13, 17, 18] and other information brochures, reference is made to further developments that reflection offers an efficient and resilient solution that is now imposed by society as a whole and above all by environmental requirements. Working principle:

• What is reflected does not need to be insulated.

In simple terms: reflection does not need a defined minimum thickness. Reflection only takes place on the surface of a material, which can be “wafer-thin”, and it needs a diathermic layer of air. A vacuum is not necessary. Rather, strength and other properties of the carrier material, such as thin foils, play an essential role.

Just the following examples for reflection: It is used very deliberately in many technical and life areas, such as the emergency blanket for accident victims. Also in nature - ant species with reflective “silverback” in the Sahara. The [ARD18] reported about the cave accident of the children's soccer group, how divers protected them against heat loss with heat protection foil. In construction, this is not the case for various reasons and with a few exceptions. In the meantime, over 100 buildings with the insulation-reflection system have been energetically renovated. There is no property in which the insulation fails or other disadvantages arise when the necessary and suitable materials and space are used correctly.

If the reflection system is pointed out in the case of a new building or renovation project, an invisible barrier is immediately in the room, which means that reflective layers can work without problems like the dew point in a layer structure. If a technical discussion is successful and interest increases, the question arises in almost all cases: Can you not combine the at least four layers (2x film and 2x air) and thus reduce the installation effort? The answer or a practicable solution to it has so far been a) not yet provided once, b) there was no corresponding emphasis or such a necessity, and c) from many perspectives it was / is not wanted in Germany at all. A practical test in a southern German company with prefabrication of wall elements did not bring the desired success.

For the construction industry, it is also important to note: the circumstances have not been bad enough to favor new ideas, and creativity is required for a mostly long process. A sweeping idea is then a sudden idea. The supposed and “visible” discovery process is only reduced to the last perceptible, conscious period of time.

It therefore took a period of several years. The realized objects were not erected within a few days and had to be used for at least one to two full years before the first data was available or findings such as advantages and weak points became apparent. And it took over 100 buildings with only heat input through radiation, including around 8 objects for which the system specifications were not implemented and / or adhered to as specified, in order to gain experience. In addition, there are social events that are difficult to grasp, such as environmental protection and the corona pandemic or impulse-like developments such as thin-walled fiber or carbon concrete. A broader reference base had an inhibiting effect: Angled buildings were more difficult to refurbish in terms of energy efficiency in order to tame thin, “lobed” film and poorly “tangible” air in a thin layer system. In the new building, on the other hand, as much as possible should be prefabricated in order to shorten the construction process and make it safer. Even the film turned out to be idiosyncratic with predominantly excellent properties. Although it lies smoothly on a floor surface, hanging freely in the air it shows its latent internal tensions from the manufacturing process. Theoretically, a reflection of radiant heat is already possible with an air gap of only 0.1 mm, but in practice the two foils could still touch each other at points, even with an air layer around 20 mm thick, if the spacers between them are too far apart. Ultimately, spacers with a large spacing grid should transmit as little heat as possible and transfer loads in the floor. As a guide, minimally heat-conducting spacers should only touch 1% of the film surface. For example, the spacing grid, the greater edge deflection and, in the case of flooring layers, the thickness of the load-bearing top layer influence each other diametrically.

1. 1) Weitere Minimierung der Gesamtdicke und damit Ressourcenschonung/Raumgewinn
2. 2) Vorfertigungs- und montagefreundliche Elementherstellung
3. 3) Vermeiden des Luftflusses vor der raumseitigen Deckschicht und zwischen den Schichten
4. 4) Robustheit zum Übertragen von Kräften
5. 5) Maximale Weiterverwendung von Restmaterial
6. 6) Optimierung mit anderen Deckschichten

If the geometry has been set and the effect has been ensured, further requirements must be met:

1. 1) Further minimization of the overall thickness and thus resource conservation / gain in space
2. 2) Prefabrication and assembly-friendly element production
3. 3) Avoidance of air flow in front of the room-side cover layer and between the layers
4. 4) Robustness for transmitting forces
5. 5) Maximum further use of residual material
6. 6) Optimization with other top layers

These 6 requirements have not been met or only insufficiently met by previous practice and must therefore be included in a new solution. In addition to the dominant effect of radiant heat - over 90% of all heat transports are based exclusively on radiant heat - the physical processes can be described a little and simply.

Physical background

It turns out that the understanding of the process of moisture and heat input into and through building materials is not sufficiently covered in the literature and in building physics.

As is well known, we assume that heat is transported in three ways: ( 1 ) Heat conduction, ( 2 ) Convection and ( 3 ) Radiation. In building physics ( 1 ) and ( 2 ) only partially considered, which in itself leads to large discrepancies in thermal insulation proofs between the calculation and the practical result. ( 3 ) is hardly or incorrectly considered. From the author's point of view, the ( 4th ) Mass-bound energy transport of water vapor fully charged with energy plays an essential role, which has an optical effect (mold formation) and can at least approximately also be determined by calculation.

Water molecules are condensed water vapor without the heat of condensation that has already been released. The usual view is that water vapor only condenses when the saturation concentration of 100% air humidity is reached and the air can no longer absorb any more water vapor. How can it be that in a dry room, on a slightly cooler wall, water droplets fall out at only around 80% room humidity, and consequently mold forms? This can be explained with surface materials or even just with "impurities" that act like a catalyst: a sufficient number, invisible, punctiform area-wide, with excellent or even self-reinforcing condensation [Wiki18]. 627 Wh are released for every 1 kg of water vapor. This evaporation heat or enthalpy is absorbed by a cooler wall surface, the wall heats up minimally and the heat is dissipated into the cooler wall material. At the same time, the wall soaks up the water droplets, it becomes a little more humid, which further increases the thermal conductivity and dissipates the heat even better. On the other hand, some of this moisture evaporates away from the wall into the room air or runs down the glass pane as condensation. At the same time, this creates evaporative cooling with heat extraction from the nearby room air and also from the wall surface. The now cooler layer of air on the wall is heavier than the neighboring, surrounding room air and sinks to the bottom. The air that is slightly dehumidified on the wall is convectively replaced by warm, moist room air flowing in from above. The process can take place again.

Previous considerations assume that only the water vapor diffuses from warm to cold, i.e. from inside to outside, according to the falling water vapor pressure. It transforms into water where the wall material is correspondingly cooler. This point is generally referred to as the dew point. This designation is misleading as it is not a point, but an unsteady area. As described above, heat is released at "this point", which warms up the wall mass locally and the colder "point area" migrates slightly outwards, releases the heat there and then moves inwards again. Who knows or who cares? It would be best if this process does not take place at all and we can change that with a new heating strategy.

1. a) Die Wandoberfläche ist sehr rein und kann nicht als Katalysator störend mitwirken.
2. b) Die Luftbewegung im Raum wird unterbunden und führt keine neue Wärme nach.
3. c) Die Wandoberfläche ist wärmer als die Raumluft und kann aus der Raumluft keine Wärme mehr aufnehmen.

This process must be interrupted or prevented entirely. This can be done as follows:

1. a) The wall surface is very clean and cannot act as a disruptive catalyst.
2. b) The air movement in the room is prevented and does not bring in any new heat.
3. c) The wall surface is warmer than the room air and can no longer absorb any heat from the room air.

To a): So far, no suitable material has been known or found whose surface does not act as a catalyst. Regardless of this, warm room air sliding past would continue to give off its heat to the wall.

Regarding b): The air movement must be prevented to such an extent that it does not reach the wall surfaces in a space-consuming manner. Local, limited-looking hot air columns such as above the head are unproblematic. Conversely, convection heating - including underfloor heating and certain forms of radiant heat tapes on ceilings - is the biggest culprit. Only radiant heat from surfaces emitting heat with a maximum of 26 ° C allows the air to lie calmly in lounges.

Regarding c): This state can only be achieved with radiant heat, without any expansive columns of warm air. This means that the room air temperature can remain below the temperature of all surfaces and objects in the room almost at will. A surface temperature of 23 ° C and a room air temperature of at least 15 ° C have proven to be favorable, although this can be deviated from for a short time, as with ventilation (burst ventilation due to hygiene). In principle, the temperature control surfaces can be arranged as desired, but better on the most suitable surfaces. The arrangement is therefore arbitrary because the radiant heat propagates in the room at the speed of light and very quickly leads to the adjustment of surfaces / objects of different temperatures.

The brief description of these four processes is important because the combination of b) and c) forms the basis for further finding a solution. The properties of the wall surfaces with their catalytic effect of a) thus play no role. This does not only apply to walls, but to all enveloping surfaces of the building. The essential element is the two reflective surfaces as a thermal barrier. Their training must meet the partly contradicting requirements - as shown above.

Solution of the given task

In the general layer structure is shown.

Compared to the previous design with the two reflective surfaces and the point-like spacers arranged as far apart as possible, each with a thickness of at least about 10 mm, a flat grid is used as in geotechnical engineering.

• - Material: harter Kunststoff, minimal Wärme leitend, formstabil
• - Maschenweite vorzugsweise ca. 40 mm; verhindert Folienkontakt und minimiert weitgehend Kontakt von Folie zu Netzstäben, welcher nur hauchdünn und linienförmig ist.
• - Maschenform: beliebig von rund-dreieckig-rechteckig/quadratisch-vieleckig, ähnlich wie Bienenwaben,
• - Netzstäbe [1]: Ø ca. 2 bis 5 mm, Querschnitt rund bis oval, auch eckig möglich, herstellungsabhängig
• - Knotenpunkte [2]: Sie bilden leichte Erhöhungen und erlauben Berührungsflächen von vorzugweise nur 1 mm² bis ausnahmsweise maximal 4 mm².
• - Sie übertragen je nach Einsatzbedingung punktuell die Materialeigenlasten und Verkehrslasten beim Fußboden und bei Decken.

The grid has the following properties:

• - Material: hard plastic, minimally heat conducting, dimensionally stable
• - Mesh size preferably approx. 40 mm; prevents film contact and largely minimizes contact between film and net rods, which is only wafer-thin and linear.
• - Mesh shape: any of round-triangular-rectangular / square-polygonal, similar to honeycombs,
• - Net rods [1]: Ø approx. 2 to 5 mm, cross-section round to oval, also angular possible, depending on the manufacture
• - Nodes [2]: They form slight elevations and allow contact areas of preferably only 1 mm ² to, exceptionally, a maximum of 4 mm ² .
• - Depending on the application, they transfer the intrinsic material loads and traffic loads on floors and ceilings selectively.

With these materials, the 6 requirements mentioned in point 2 can be largely met:

1) Minimizing the overall thickness

The two grids work with the two foils like the usual insulation, only much slimmer and much more efficient. It is also around half as thick as the previous Erifolsystem ^{® [Erifol15].} If the four layers are connected to one another (loops) or glued at the edge, it is sufficiently dimensionally stable as a layer package with a maximum thickness of around 10 mm, is light and easy to assemble.

2) Prefabrication and assembly-friendly element production

With the cover on the room side [ 3 ] a disc forms. These panes can be easily mounted with tongue and groove and secured to the wall with dowels. These pane elements can be prefabricated or can be produced on the construction site according to the assembly process with, for example, OSB panels and thus meet the requirements of the Construction Products Regulation of [EU13].

3) Avoidance of air flow in front of the room-side cover layer and between the layers

If the building is airtight - checked with an airtightness test - the outer reflective film [ 9 ] simply lie on the inside on the outside, gluing is not necessary. A small and almost impossible to prevent air gap between the film [ 9 ] and optional condensate insulation [ 10 ] or external component [ 11 ] is advantageous for summer heat protection, because the outside of the outer reflective film lower than the glossy inside, but still sufficiently well reflected. Overall, sensitive or susceptible external components can be sealed beforehand and connected to the layer package before the installation of the layer package. Overall, it serves to ensure the building's tightness, even if the insulation does not represent the building's tightness level, but can support it.

4) Robustness for transmitting forces

The two grids can be offset. When under load (if at all) they push their way through to the maximum and selectively down to the intersecting net bars. They are prevented or deformed slightly by an extremely resilient and tear-resistant reflective film. The bars form an additional barrier against any air flowing through.

With an additional cladding such as plasterboard on the walls, the pane effect can be increased and / or the haptic properties can be improved.

In the case of the floor, the rest of the floor construction can be carried out on top of it and traffic loads can no longer be transferred with spacers further away, but evenly via the grids.

5) Re-use of residual material

In the previous Erifol ^® system, each layer was installed one after the other. That was quite easy, but still tedious and there were several off-cuts. Depending on their shape and size, these were largely and painstakingly reused. With the current layer package, there is also waste, but it can be laid out next to one another more quickly, especially in the floor area, so that the remainder is hardly significant.

6) Combine with other top layers

The room-side cover [ 3 ] can meet the normal functional requirements of the room, but it can also take on other functions, such as fire or noise protection, depending on the requirements. On the room side of the ceiling, wall and floor, between the grilles [ 1 ], [ 4th ] and cladding [ 3 ] add temperature control elements that warm up the surface on the room side in the living rooms to a maximum of 26 ° C and thus prevent fully effective convection processes on the interior surface. The size of the temperature control surfaces required for this is calculated separately so that all components and furnishings can be heated to 23 ° C. The cladding on the ceiling can advantageously also be a thin sub-span ceiling, which facilitates the passage of heat. In the case of very thin load-bearing walls such as those made of fiber concrete (textile, carbon C ³ ), there may be a gap between the outer reflective film 9 ] and the wall [ 10 ] to arrange an insulation layer due to "penetrating" cold of a maximum of 20 mm or to integrate it into the system structure.

Legend for the layer structure

Scale approx. 4: 1

1 Lattice bar (cut) Ø approx. 1 to 3 mm, round ... oval ... square 2 Thickening due to crossed bars approx. 2 to 4 mm 3 room-side cover depending on the function ~ 3 - 15 mm thick 4th inner bar visible at the back 5 inner air gap ~ 1 - 3 mm 6th inner reflective film close to the outer grille 7th Outside bar visible at the back 8th outer air gap ~ 1 - 3 mm 9 outer reflective film loosely attached to the outer component 10 Anti-condensation insulation optional 11 External component depending on the function wall, ceiling, etc.

short version

The invention includes an arrangement of reflective layers and spacer grids for thermal insulation of external elements such as walls, floors and ceilings. An outer layer is made of a highly reflective, thin, tear-resistant material [ 9 ] directly onto the outer element to be insulated from the inside [ 10 , 11 ] appropriate. A grid is placed on top as a spacer [ 7th ]. Usually this is followed by a second thin reflective layer [ 6th ], again with grille [ 4th ]. The conclusion is an inner shell [ 3 ] - an interior lining or base layer (floor). The inner shell can be made of different materials Material such as wood, plasterboard, stretch ceiling are made. The grids consist of largely rigid and thin grid strands that are fixed to one another and are thickened at the nodes and can transfer forces through them.

literature

ARD18 ARD news broadcast 04.07.2018, 8 p.m. report on cave accident in Thailand Beuth15 Beuth Hochschule Berlin, ifeu 2015, Prognos p. 31 Erifol15 Erifol brand, 30 2015 101 757 EU13 EU Construction Products Regulation of July 1st, 2013. REGULATION (EU) No. 305/2011 OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 9 March 2011 laying down harmonized conditions for the marketing of construction products and repealing Council Directive 89/106 / EEC focus20 https://www.focus.de/finanzen/news/konjektiven/klimaschutz-absurd-umsonstgedaemmtenergiewende-wird-im-gebaeude-bereich-zum-millionen-grab_id_12490652.html Horn12 Horn Wolfgang. Heat transport and insulation through Lu..po.Therm material. IB Horn, June 22nd, 2012 Horn13 Horn, Wolfgang: Thermal insulation with flexible reflection material. Utility model 08/21/2013 Horn17 Horn, Wolfgang: Anti-condensation insulation for thin and / or highly thermally conductive external components. Utility model 07/28/2017 Horn18 Horn, Wolfgang, Hinz Volker: DE 10 2018 005 814 A1 , 2019.01.31 Meier09 Meier, Claus: Build properly. Physics in Twilight - Problems and Solutions. 7th edition 2009, expert verlag Meier10 Meier, Claus: Radiation heating phenomenon, expert verlag, 2nd edition 2010 Wiki18 Wikipedia 2018: "Nucleation or nucleation is the first sub-process that initiates a first-order phase transition ..."

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102018005814 A1 [0031]

Claims (7)

Layer package for the thermal protection of rooms with dominant radiant heat input and without heat-effective convection processes in buildings or vehicles and ships on the external components such as walls, floors or ceilings, consisting from the outside to the inside a) External component [11] made of any heat-conducting material layers that have a static-constructive effect and meet requirements such as fire, moisture, sound, weather, aesthetics, b) optionally an adjacent anti-condensate insulation [10] c) In front of this, usually two-layer, heat-reflecting foils [6], [9] separated by grid elements [4], [7] with respective air gaps [5], [8], d) a visual, protective or functional cladding as a thermal barrier. Layer structure according to Claim 1 , characterized in that the grids are preferably made of dimensionally stable materials and shapes with low or only moderate heat conduction with thermal conductivity values of approx. λ = 0.2 W / (mK) and can also be composite materials. Layer structure according to Claim 2 , characterized in that the shape of the bars are preferably round or flattened and the bars can have any shape, preferably square by crossed bars as in a network, which are up to twice as thick at the nodes [2]. Layer structure according to Claim 2 , characterized in that the thicker crossing points [2] can only be pressed minimally into the highly resilient reflective foils [6], [9] and thus a minimal air gap of ~ 1 to 2 mm is formed between the bars and the reflective foil an air flow in the air layer [5], [8] is obstructed and, on the other hand, a thermal conduction is interrupted. Layer structure according to Claim 1 , characterized in that optionally between the room-side cover [3] and the inner grid [4] a) a water-guided temperature control grid according to the Tichelmann principle or b) a carbon film for electrical temperature control is installed. Layer structure according to Claim 1 , characterized in that a) the grid elements and foils are connected to one another or linked by means of loops or gluing at points, b) this grid-foil package - placed on the building site on the covering layers (floor) or leaning against (wall) or attached ( Ceiling) or - be placed in molds at the factory and locked in place for assembly with cover layers. Layer structure according to Claim 1 , characterized in that the sequence of layers a) to d) is reversed accordingly and the latter transfer static loads as on the roof ceiling in the cold roof or are weather-resistant.

Images