Structural engineering suggestion for
VAKUUM wall modules
Because of the insoluble environmental problems in cement production and the mining of building sand, completely new approaches must be taken in the construction sector
In the operating principle of a thermos flask*, coffee, for example, remains hot until the next day - thanks to two wafer-thin, silvery glasses and a rough vacuum. The different wavelengths created here find a thermophysical barrier that is much slower.
The thin "MLI films" used in space travel under vacuum also replace the storage mass and all insulating materials commonly used in our buildings. In space, these films actually protect against much higher temperature differences than those found on earth.
Here on earth, a vacuum enclosed in modules and reflective foils enable optimal building insulation.
Before the building description follows, I would like to mention the advantages of this construction method:
# The greatest advantage, however, comes with the global reduction in CO², which can and will take place as a result of the paradigm shift that is taking place in the construction industry - because building sand will simply be too expensive in the future!
To the state of the art:
Similarly conceived products are already on the market.
These "VIP Panels" cost, through the complex processes of their Production, per m² up to 100.- €!
They are not leak-proof in the long term or their vacuum cannot be readjusted - and above all - they do not provide a static function.
Statically stable vacuum modules are not yet evident on the market, but "VIG windows" are already available in vacuum design.
This licence-free approach published here is therefore "state of the art".
How are these components manufactured?
The module frames support tempered glass, sheet or OSB panels on both sides.
The OSBs (or sheets) have 20 my thick aluminium foils glued to their visible surfaces with Zapon varnish (which can be painted in the desired colour). On the room side, wallpaper can also make painting unnecessary.
Between the panels are squared timber uprights, arranged in rows, with maximum dryness. The uprights are glued together along two blunt edges. Their two sharp edges, on the other hand, lie against the two OSBs. This minimal contact between the longitudinal edges means that no significant thermal transfer occurs.
The module frame is made of 16 mm thick plywood with interlocking at its four corners. The OSB's are each framed by the frame rebate running all the way round and elastomerically bonded to it. The result is permanently gas-tight sandwich elements.
Only the module joints have insulating strips that are visible on the outside.
Squared timber uprights
They are delivered from the factory with half negative pressure.
Cables and other installations are laid in separate shafts between the module joints.
After construction, a rotary vane pump is used to create an atmospheric height-dependent vacuum of about 95 % in each module field. The suction valves are located on the living space side and allow for readjustment of the air diffusion that will occur over the years.
If the facade surfaces are covered with PV-foil, this results in a completely energy self-sufficient building, whose excess electricity can also serve the charging station for e-mobility!
A corresponding number of transparent acrylic spacers are inserted between window panes or full-surface glass elements, distributed over their surface. These surfaces can also be readjusted via valves. An excess of UV radiation could be reflected by UV/IR foils; or sun blinds placed outside regulate the desired temperature by auto-sensors.
With a solar-thermally supported heat pump heating system and fresh air via heat exchanger, an economical indoor climate is ensured all year round.
>> All in all, sustainable building and living is possible! <<
What does one m² of vacuum wall cost approximately?
2 m² Kronoply-OSB, 12 mm 46,- €
2 m² aluminium foil 2,- €
17 lm squared timber + 2 lm plywood + elastomer ~ 30,- €
Working time of prefabrication per m² ~ 22,- €
- " - at the building site in about 20.- €
= in total about 120,- € *
* This estimate is based on series production, excluding pricing at the expected profit.
The decision of the building owners is therefore likely to be made more and more often in favour of this type of construction; solid construction costs about twice to several times as much per m² (not counting the product life cycle with demolition costs)!
Market surveillance for construction products is the responsibility of the respective authorities; building physics institutes are responsible for the corresponding certification in the areas of insulation, fire protection, sound insulation and structural integrity.
Source: IPCC / Cement production emits more CO² than air traffic and shipping together.
With the costs for building sand, which will certainly continue to rise, a change in our construction engineering practice is inevitable. A change from cement, sand, polystyrene and reinforcing steel - to wood and
Vacuum-integrated glass as well as on applied PV-foils is sustainable, future-proof and desirable.
Vacuum wall modules are foreseeable energy and resource savers in the construction phase as well as in the utilisation phase! Their recycling also requires only little effort.
Furthermore, there is an urgent need to reduce the CO²-polluting cement production and the ecological consequences of over-exploitation of building sand. The food chain of maritime life begins with micro-diversity, which is mainly based on sandy seabeds!
* The vacuum vessel was used by the chemist James Dewar in calorimetric experiments as early as 1874.  These vessels, now known as Dewar vessels, were made of metal.  Only later were they made from glass flasks placed inside one another. To reduce heat radiation, Dewar mirrored the inner surfaces of the glass vessels (Wikipedia).
In admiration of his inventive achievement, it fell to me to design their extension towards thermal construction elements.
= = = = =
With a technically similar approach, sunlit, solid exterior walls are able to heat the rooms behind them with stored thermal radiation from free solar energy.
These walls are clad on the outside with glass and on the inside with sheet metal, plywood or OSB's on vertical, spacing rear-ventilation laths. They form the basis for vacuum-controlled heat storage and can be retrofitted to almost any building.
During the day - at normal pressure - the wall mass behind the glass heats up. In the evening, the outer façade is heated by means of automatic
Control to the vacuum insulation which was upright to the inside of the room during the day.
Now a continuous heat radiation, distributed over the night, is emitted into the rooms behind.
On hot days, an externally placed, sensor-regulated sun blind prevents the storage wall from overheating or undesired heating.
# Both constructional approaches could be implemented by medium-sized craft businesses.
I cannot give any values for scalability, R+D etc., because I am not familiar with business administration, for example.
> In the sense of fulfilling our SDGs ! <
Copyright 2008, Graz, Austria - updated, Vienna, October 2019 - Michael Thalhammer
Buildings can become a global CO2 sink - with the building material wood instead of cement and steel
01/28/2020 - A material revolution that replaces cement and steel with wood in urban development can have a double benefit for climate stabilization. This is now shown by a study by an international team of scientists. First, it can avoid greenhouse gas emissions from cement and steel production. Second, it can turn buildings into a carbon sink, since the timber stores the CO2 previously absorbed from the air by the trees and stored in their trunks. Although the required amount of wood is theoretically available, such an expansion would require very careful sustainable forest management, the authors emphasize. Buildings can become a global CO2 sink - with the building material wood instead of cement and steel High-rise construction with wood.
Photo: naturallywood.com - KK Law
"Urbanization and population growth will create tremendous demand for the construction of new residential and commercial buildings - therefore, if we don't act, cement and steel production will remain a major source of greenhouse gases," says lead study author Galina Churkina, who both belongs to the Yale School of Forestry and Environmental Studies in the USA and the Potsdam Institute for Climate Impact Research in Germany (PIK). "However, these risks for the global climate system can be transformed into an effective means of containing climate change if we increase the use of engineered wood in the global construction sector. Our analysis shows that this potential can be realized under two conditions First: The harvested forests are managed sustainably. Second: The wood from the demolition of buildings is reused.
" Four scenarios of wood use as a contribution to climate stabilization The scientists calculated four scenarios for the next thirty years. Assuming "business as usual", only 0.5 percent of new buildings will be built with wood by 2050. This proportion could rise to 10 percent or 50 percent if mass wood production increases accordingly. If countries with a current low level of industrialization manage the transition, even 90 percent wood is conceivable in construction, explain the researchers. This could result in storing between 10 million tons of carbon per year in the lowest scenario and nearly 700 million tons in the highest scenario. In addition, the construction of wooden buildings permanently reduces the cumulative emissions of greenhouse gases from steel and cement production by at least half. This may not seem so much compared to the current amount of around 11,000 million tons of global carbon emissions worldwide per year (for better comparability, these figures are here in carbon, not in CO2). But switching to wood would make a difference in meeting the climate stabilization goals of the Paris Agreement.
Assuming that concrete and steel will continue to be used for construction and that the floor area per person will increase in line with the current trend, the cumulative emissions from mineral building materials could reach up to a fifth of the CO2 emissions budget by 2050 - a budget that should not be exceeded if we want to keep warming well below 2 ° C, as the governments promised in the Paris Agreement.
It is important that the countries of the world need CO2 sinks in order to reduce their greenhouse gas emissions to net zero by the middle of the century. Only with these can they offset the remaining emissions that are difficult to avoid, especially those from agriculture. Buildings could be such a sink - if they are made of wood. A five-story residential building made of glued laminated timber can store up to 180 kilograms of carbon per square meter, which is three times more than the aboveground biomass of natural forests with a high carbon density.
Nevertheless, even in the 90 percent wood scenario, the carbon accumulated in wooden cities over thirty years would be less than a tenth of the total amount of carbon stored above ground in forests worldwide. "It is crucial to protect forests from unsustainable deforestation" "If the use of construction timber is to be increased significantly, the protection of forests against unsustainable deforestation and a multitude of other threats is crucial," emphasizes co-author Christopher Reyer from PIK. "However, our vision for sustainable management and regulation could actually improve the situation of forests worldwide, since a higher value would then be assigned to them," emphasizes Christopher Reyer from PIK.
The scientists summarize several document chains, from official statistics on wood harvests to complex simulation models, and on this basis determine that theoretically the currently unused potential of the global wood harvest would cover the needs of the 10 percent wood scenario. It could even meet the needs of the 50 and 90 percent wood scenarios if the floor area per person in buildings worldwide did not increase but instead stayed at the current average. "There is a great deal of uncertainty here, as well as a strong need for political measures to upgrade forests and their products, but in general it looks promising," says Reyer. "In addition, plantations would be required to meet the demand, including the cultivation of fast-growing bamboo by small landowners in tropical and subtropical regions." If the use of round wood as fuel were also reduced - around half of the round wood is currently burned, which also leads to emissions - more of it could be made available for building with processed wood-based materials. In addition, reusing wood after buildings are demolished can increase the amount of wood available. The technology of trees - "to build us a safe home on earth" Wood as a building material has a number of interesting characteristics that are described in the analysis. For example, large lumber, when used correctly, is comparatively fire resistant - its inner core is protected by the charring of its outer layer when it burns, making it difficult for a fire to destroy the supporting structure. This is in contrast to the widespread assumption that wooden buildings are flammable. Many national building codes already recognize these properties. "Trees offer us a technology of unparalleled perfection," says Hans Joachim Schellnhuber, co-author of the study and emeritus director of PIK. "They take CO2 from our atmosphere and convert it into oxygen to breathe and into carbon in the tree trunk that we can use. I can't think of a safer way to store carbon. Humankind has used wood for buildings for many centuries, but now it works in the face of the challenge of climate stabilization by a whole new order of magnitude. If we process the wood into modern building materials and manage the harvest and construction wisely, we humans can build a safe home on earth " Article: Galina Churkina, Alan Organschi, Christopher P. O. Reyer, Andrew Ruff, Kira Vinke, Zhu Liu, Barbara K. Reck, T. E. Graedel, Hans Joachim Schellnhuber (2020): Buildings as a global carbon sink. Nature Sustainability [DOI: 10.1038 / s41893-019-0462-4] Web link to the article: https://www.nature.com/articles/s41893-019-0462-4 Source: Potsdam Institute for Climate and Impact Research