Zehnder Carma dual-flow ventilation units in a Passivhaus-certified gymnasium

Innovative, sustainable and passive sports equipment for the future eco-district of Val-de-Vesle

Project display

Designed by the Reims-based firm Haïku Architecture, this project is a multi-purpose sports facility intended to meet the needs of future users: the local sports association and the schools in the area.

The program consists of:

• a reception hall serving as a foyer and clubhouse,
• a large multi-purpose hall: a multi-sports field dedicated to local associations and schools,
• a small multipurpose room: a room intended for dance activities, sophrology...

The building will be one of the focal points of the future eco-district to be developed to the south and west of the site selected for the project. The building's main facade and entrance face southwest, towards the heart of the village. This facility will become a key element in the Val-de-Vesle area. The 45-space parking lot is located next to the train station. It meets the needs of building users and also serves as a park-and-ride facility for travelers, encouraging active transportation.

The southwest-facing entrance façade is protected by a canopy that shelters the wooden cladding, visitors, and bicycles. A forecourt, lined with benches, offers a welcoming and convivial space open to the heart of the village.
 

A bioclimatic, low-carbon and passive design

To meet the client's specifications, Haïku Architecture designed the project using bioclimatic principles, with a highly compact form to minimize heat loss. On the east and west gable ends, storage areas act as thermal buffers, enhancing the efficiency of the main hall's envelope. The building is oriented north-south, creating a long façade with significant solar gain. The south façade is welcoming and sunny, with a forecourt facing the heart of the village. This main façade is protected from inclement weather and summer sun by a wide canopy.

The building is certified passive and meets the objectives of the PassivHaus standard:

• a heating requirement of less than 15 kWh of useful energy per m² of energy reference surface per year;
• a total primary energy consumption of less than 120 kWh per m² of energy reference surface per year;
• an air permeability of the envelope measured under 50 Pascals of pressure difference less than or equal to 0,6 per hour.

For an indoor temperature of 20°C, the building's annual heating requirements will be 11.755 kWh/year, representing an average heating cost of approximately €2.350/year (average price per kWh: €0.20 including VAT) for a surface area of ​​1.240 m². These annual heating requirements for an indoor temperature of 16°C (common in gymnasiums) will then be estimated at 3.93 kWh/m².year, or 4.873 kWh/year (heating consumption cost < €1.000/year).

For comparison, an unrenovated 1970s gymnasium in operation has a heating operating cost of between €30.000 and €35.000 for an indoor temperature of +16°C; an indoor overheating frequency (> 25°C) of less than 10% of the hours of the year.

The project is also designed with a low-carbon approach, favoring bio-based and recyclable materials:

• The structure is made of a timber frame.
• The insulation is mostly bio-based, made of wood fiber.
• the cladding in raw Douglas fir siding.

The 780 m2 green roof is equipped with 90 photovoltaic panels covering approximately 40% of the electrical needs, in line with a positive energy building approach. Solar electricity powers technical equipment, including ventilation systems, with surplus energy used for lighting.
 

High-performance Zehnder ventilation at the heart of the passive project

In such a demanding building, indoor air quality and the control of energy losses are major issues.

“The construction of a passive building can only be done with a high-performance dual-flow ventilation system, meeting the Passivhaus criteria through equipment certification that ensures the efficiency of the air handling unit heat exchangers, which is taken into account in the PHPP calculations. The higher the heat exchanger efficiency, the better we ensure the success of the project,” explains Mr. Sauvage, Thermal Design Office BETS.

"It is therefore important and essential to assess the results by prioritizing dual-flow AHUs with high recovery efficiency and also with virtuous and efficient electricity consumption. In addition, we ensure the acoustic comfort of the selected equipment ," he adds.

In this project, the selection of dual-flow air handling units was carried out by the thermal design office according to the following criteria:

exchanger efficiency,
• electricity consumption,
• acoustic level,
• Up-to-date Passiv'Haus certificate.

Thus, the multi-activity hall in Val de Vesle is equipped with three Zehnder Carma dual-flow air handling units, manufactured in France and adapted to passive buildings.

They ensure optimal ventilation while effectively limiting heating needs thanks to their high-efficiency heat recovery system:

• Two Zehnder Carma 9048 air handling units (air flow up to 6000 m3/h) are installed at each end of the large 800 m2 hall to treat the interior of the sports venue,
• 1 Zehnder Carma 9016 central unit (air flow up to 1800 m3/h) in the changing room area.

Certified by the Passive House Institute (PHI), which guarantees a heat recovery rate of 86%, and by EUROVENT, the thermal performance of these units, equipped with a very high-efficiency plate heat exchanger, was a decisive selection criterion for engineering firms. The units ensure efficient and continuous filtration of fresh air using F7 filters and filtration of return air using M5 filters.

Delivered without integrated controls, the air handling units (AHUs) are paired with a complete controller including meters and sensors for regular performance measurement. The implemented control protocol allows for centralized and remote management via a building management system (BMS), in line with the client's desire to precisely control energy consumption and user comfort.

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