If you look at the project credits for any notable sustainable building these days, chances are you will come across Transsolar. Founded in Germany, the company is active worldwide, bringing its brand of climate engineering — or KlimaEngineering — to public and institutional works. Recent high-profile credits include Winnipeg’s Leaf, by KPMB Architects with Architecture49, and Toronto’s own Limberlost Place, by Moriyama Teshima Architects and Acton Ostry Architects; as well as globally notable projects like the CERN Science Gateway in Geneva by Renzo Piano Building Workshop and Brodbeck Roulet Architectes. These architecture firms bring on Transsolar to help them derive solutions for making their projects as sustainable as possible.

Tommaso Bitossi, an Italian-born and -educated architect and Associate Partner at the firm, describes its ethos as one of innovation driven by a passive design–first approach, which he terms “sufficiency before efficiency.”

“The core meaning of ‘sufficiency before efficiency’ is looking at how efficiency, in the past, has failed us. In other words, our computers now are much more efficient than in 1995. However, now we have two laptops per person, one iPad, one smartphone, etc. So… our carbon emissions didn’t change. Perhaps they increased! Or, our servers are now cooled very efficiently, but, with the advent of AI, we are exponentially increasing our need for data storage and computational power. Again, did efficiency save us?

“Sufficiency will save us, together with efficiency.”

The firm looks at a problem dynamically, performing sophisticated simulations on its custom software that models the very physics of a building design and its site conditions – thermal, energy, daylight, etc. These studies are used to prove a concept and understand the “sensitivity of certain variables,” and then to make design decisions. “What is the energy of the building if I do this or that?” Bitossi explains. “We rarely use simulations to ‘predict’… because real life can be very different, mostly due to unpredictable user behaviour.”

In the lead-up to AZURE’s Human/Nature conference — taking place in Toronto on October 24-25 — where Bitossi is a keynote speaker, here are a few highlights from the firm’s portfolio:

Villa Viva Haus, Hamburg, by Me Di Um Architekten

At this “social guest house,” run by Heimathafen Hotels and the non-profit organization Viva con Agua, which advocates for universal access to clean drinking water, the designers at me di um Architekten and Transsolar made the mechanics of the building legible to patrons — and to Viva con Agua’s staffers, who also have their HQ here. The key move was to create a buffer storage tank for water heating and place it in the atrium — so that it is a visible feature of the design, the intention being to communicate the inner workings of the eco-efficient architecture.

“Residential needs a lot of hot water (for showering) year-round, and high-temperature water is not easy to efficiently generate with an all-electric heat pump,” Bitossi explains. “So, here we generate it with solar thermal panels and store it. Together with the design team, we decided to celebrate this technological moment and use it to raise awareness — and to show a design philosophy where a mechanical system can be part of the design. 

“We could have hidden the buffer storage tank underground, but hiding mechanical systems creates a lot of embodied carbon; it requires excavation, concrete, water proofing, et cetera. Or, we could have built a wall around it, again increasing the project’s embodied carbon. So, we decided to expose it. It looks beautiful to me, and people always ask ‘what is that?’… And that’s how they learn.”

CERN Science Gateway, Geneva, by Renzo Piano Building Workshop in collaboration with Brodbeck Roulet Architectes

In seeking to make the wonders of science engaging to the greater public, the European Organization for Nuclear Research commissioned RPBW to design this welcoming facility. The firm devised a campus of four pavilions and two tubular structures that are inspired by CERN’s Large Hadron Collider. Transsolar came onboard to make the auditorium experience as comfortable as possible for visitors of all ages.

“In this project, we applied a well-known principle, though it is still state-of-the-art for auditoriums. In auditoriums, you need a lot of air because you have a lot of people and this air typically requires much heating and cooling. In an all-air system, you can supply this air from the top, which is not efficient, or from the bottom, which is very efficient. If you supply from the bottom (where your feet are), you need to do so at a very low velocity. 

“So the innovation is how to apply a known principle (displacement ventilation) in a way that is pretty unconventional. We needed flexibility, so we said, Let’s just perforate the entire floor. When you have a lot of floor area, you end up with a lot of area where the air can slowly move through. Usually, you apply that principle with off-the-shelf diffusers, and you have a manufacturer certifying how they perform. But when you perforate a floor, there is no manufacturer certifying that. So we had to do our homework, run CFD studies, to prove that it would have worked acoustically and also thermally.”

The Leaf, Winnipeg, by KPMB Architects with Architecture49

With its spiral roof in ETFE, The Leaf is a marvellous structure that promotes the health of the plant life flourishing within it as well as the broader mandate of the the Assiniboine Park Conservatory.

“This is a project that’s very dear to me. The hypothesis: a high-performance roof that allows the visitor to connect to the outside as if it weren’t there. To have that visual connection, you need a very thin structure, and historically the only way to have a thin structure is to work with single glazing, which is very inefficient, especially in a cold climate like Winnipeg. To have efficiency, you need a double glazing, if not triple. But then your structure becomes much more visible, and you ruin the visitor experience – suddenly it feels like you’re inside a conservatory and not a subtropical forest. Not to mention, double and triple glazing would bring in less natural daylight, which is essential for the plants to grow.

“ETFE performs much better than single glazing and the structure is super thin – you get a lot of daylight. Here the compromise is between energy and user experience. In order to boost the energy efficiency of the biomes, we used ‘roots heating’: we have pipes of warm water (like in a radiant floor) that pass through the roots. This lets us keep the air in the biome at lower temperatures while still allowing the plants to grow, because their roots are warm. In summer, the biomes are completely naturally ventilated.”

Limberlost Place by Moriyama Teshima Architects and Acton Ostry Architects

This much-anticipated tall timber building in Toronto – designed to house the architecture department, and more, at the George Brown Waterfront Campus – is finally almost complete. Setting a significant precedent for how to employ CLT throughout a building design, the project (formerly known as The Arbour) has already earned many accolades. One of its standout features is a climate-response facade with integrated ventilation, which encourages the flow of natural air and daylight into the student spaces.

“This project is designed to work in 100 per cent natural ventilation mode, without any fan assist whatsoever. And it has a lot of classrooms (which requires a lot of air). Of course, there are periods where the building reverts to mechanical model (when it’s too cold or hot/humid outside). So it is a building that can work in mixed-mode ventilation.

“The façade is key: It’s motorized. We control the air flow through the opening and closing of the windows. This is the scariest part for a mechanical engineer! MEPs pressurize the building by mechanical means (aka fans). When there are no fans, you need to control the airflow by opening and closing the windows – like you do in a car, or at home. And since this is a public building, this happens through a centralized brain (the BAS) and the windows control the airflow at different levels.”

Photo of The Leaf, top of article, by Ema Peter.