from hyper-tech to cutting-edge technology

View of the hall dedicated to structural work during the Batimat @Oslo exhibition

The Batimat show, which was held from October 3 to 6, 2022 at Porte de Versailles in Paris, is intended to be the show for innovation, sustainable innovation. In the aisles given over to lobbies of all kinds, pitfalls and pretense obviously abound. To the point of creating a smokescreen in the face of the virtuous unexpected?

The month of October is, every other year, synonymous with Batimat, the trade fair for construction players. The opportunity for me to return to this major event through the reflection of a friend crossed in the aisles of the show. Arrived there by chance because totally foreign to the world of construction, this friend was so amazed, from one stand to another, everything seemed to him ” super technological », very far from the image he had of the world of construction.

I must admit that I have been walking the alleys of Batimat for more than 25 years, first as a civil engineering student, then as an architecture student and finally as a practitioner. So this technological enchantment has somewhat disappeared for me. However, each of the exhibitors is there to present their innovations and, in these times of RE 2020, everyone is going for their low-carbon innovation.

This debauchery of technology, sometimes extremely delicate to implement, gives food for thought when, at the same time, on construction sites, everyone knows how much architects have to do with a poorly or even unskilled workforce… What happens when all these hyper-sharp systems are not implemented with the millimeter accuracy of a laboratory?

In these times when it is also explained to us that the future is ‘low tech’, a return to the most primary, not to say primitive, construction techniques, it is permissible to wonder about this debauchery of technologies, these years of research and development, all this gray matter implemented if, finally, we must turn to vernacular construction.

From stand to stand, the message is the same: production compliance with RE2020. Each manufacturer has skilfully followed government guidelines to reduce the carbon footprint, so discussing aluminum joinery profiles with them to learn that theirs are all perfectly compliant. Everyone knows how aluminum is a highly polluting and energy-intensive process, but everyone can be reassured that the FDES were negotiated by representatives of the profession. Thus, the quantity of aluminum to be recycled being a maximum of 45% of the production of all the manufacturers, the latter have obtained their certification as virtuous producers…

At the same time, how could it be otherwise? If it is necessary to maximize the passive solar gains, large carpentry is required. However, the followers of ‘low tech’ have not yet shown how to make ‘low-tech’ joinery and, in this context, aluminum remains very useful and not necessarily more problematic than the steel whose manufacturers have they too negotiated wooden cross iron cross » that they recycled everything that could be recycled in order to obtain their famous FDES sesame, the absence of which could cripple any project using their products.

In reality, the discussions with the industrialists make it possible to better put into perspective the great mathematical discourses of carbon balance analysis sold by some as absolutely correct. In fact, each sector has negotiated its life cycle analysis with the authorities.

How to do otherwise. If, for example, the entire sector announces that the joinery produced is installed to last and, that to date, even by distributing it equitably among all profile producers, this raw material resulting from the recycling of the oldest joinery aluminum that we are beginning to dismantle can only represent 45% of production… Manufacturers cannot invent material to recycle and as the need for aluminum joinery remains, the balance must be a little ” embellished “.

Another example. Everyone knows that the wood industry has benefited from a recovery treatment based on the principle that the wood was produced in France in sustainably managed forests… even if everyone knows that the country does not produce enough wood… All this is quite normal so that the world of construction does not stop suddenly. However, all this has little to do with an absolute and clear mathematical calculation as they try to make us believe, but with, as always, a struggle for influence between industrialists to prevent their activity from being disadvantaged, if not crossed out with a stroke of the pen…

A tour of the aisles of heating manufacturers allows a completely different approach, each presenting its latest heat pump, relegating one or two gas boiler(s) that have become unsaleable to the back of the stand… But the discourse , once the commercial veneer has been crossed, is worrying to say the least. All manufacturers are unanimous on the fact that heat pumps are not a viable answer, but an imposed one! Indeed, the most common heat pumps called air-air or air-water, as the manufacturers themselves admit, work perfectly in mid-season but none can provide enough power in the event of extreme cold… is not even certain that they can guarantee the legal 19°!

But the government deposit is what it is… and the subsidies too… So after having rolled out gas boilers for the past fifteen years, here we are, rolling out heat pumps without this being a real answer. The difference: a coefficient of 10 on the purchase cost! When a gas boiler costs €1,500, its heat pump equivalent costs €15,000!

Are we really no longer capable of having efficient heating systems? If of course, first of all the water-to-water heat pumps. In other words, geothermal energy, either horizontal but you need large areas, which is no longer fashionable… or vertical, but the cost is even higher. As for considering the recovery of heat from a water table… So many administrative authorizations are needed… In other words: unthinkable!

In short, nothing joyful in this environment of thermal comfort…

However, looking carefully, an industrialist, not the least, in the middle of his heat pumps, offered another way, that of hydrogen! An original approach to say the least at a time when we are showered with glowing comments on this gas, as well as demonstrations of the complexity of producing it greenly. This manufacturer offers to produce it individually.

Thanks to a machine the size of a boiler, with photovoltaic panels for green electricity and connected to the water network, he proposes to produce his own hydrogen to be injected… into the gas boiler! And it works! Since 2019, there are buildings heated in this way in the Netherlands!

It may seem surprising to discover that with modest equipment, we know how to produce hydrogen to inject it into a boiler, while the government prefers to subsidize inoperative systems at great expense… Why such a strategy? Sustainable development ? Or the pressure from lobbies who will be able to continue to sell subscriptions and gas or electricity at great expense in the event of extreme cold? Or simply a lack of ambition and vision for the future?

This also raises questions about the relevance of the discourse on the difficulty of producing green hydrogen, which today leads to sending everyone to buy electric vehicles with a more than questionable carbon footprint! If with a device as big as a fridge and a few solar panels, everyone has the capacity to produce hydrogen to heat their homes, their hot water and recharge their cars, you don’t need to be a great cleric to understand that, for suppliers energy, there will be a shortfall!

On closer inspection, in fact, contrary to the image commonly conveyed by the construction industry, there was cutting-edge technology at Batimat.

Stephane Vedrenne
Urbanist architect

Find all the Chronicles of Stéphane Védrenne

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