1ST POSITIVE - ENERGY SWIMMING POOL IN FRANCE

ALICE MILLIAT SWIMMING POOL IN BOURGOIN JALLIEU

The Alice Milliat swimming pool serves the community and replaces a local Tournesol swimming pool. Located in the heart of the city, it is intended to improve accessibility for larger sections of the conglomeration’s population. The goal is to make the most of this new facility to give it truly intermunicipal status by expanding its public and activity capacity. The new facility designed by Atelier PO&PO architects aims to be a flagship in terms of energy transition and to obtain the BEPOS (positive-energy building) label – a first in France and apparently in Europe.

The Bourgoin aquatic facility focuses on teaching people to swim and diversified sports activities for the public and clubs. With a capacity of 450 users, it includes a single 8-lane pool equipped with a movable floor to manage shared activities as well as a paddling pool (no specific outdoor activities). The objective was to create a quality building in terms of comfort, sanitation, construction materials and operation.

The indoor pool is equipped with a thermal cover for closing hours. This device limits water evaporation while the pool is unused (minus 60%), by itself generating 30% savings on the project’s heating needs. The pool is insulated on all sides adjoined by technical rooms, contributing to a 13% reduction in total heat consumption. The building is ventilated through the intake of fresh air, with flow rates reduced by 60% when unused, and by natural ventilation in mid-season.

The building’s thermal envelope is highly efficient: the evenness of the natural lighting is ensured by large north-facing saw-tooth roofs equipped with triple glazing, and special attention is paid to the treatment of all thermal bridges. In addition, the building is connected to the city’s heating network, 80% of the heat coming from renewable energy sources that include an over 600 m² photovoltaic installation that meets more than a third of its electricity needs.

The facility is an expression of programmatic and functional rigour. This includes a single competition pool with no outdoor pools, wellness area or water attractions. The principles of modularity and prioritized versatility yield a pool with a movable floor and eight lanes, stands with retractable barriers, a high-performance building envelope, bioclimatology, considerable natural lighting, a thermal cover, pool insulation and technical rooms, and potential for natural ventilation.

Efficient devices have been installed, such as fans for high heat-recovery efficiency and low consumption, a heated floor in the wet rooms, and reduced air flow in unoccupied areas. Renewable and recovered energy contributes to a large degree to the heating network, 700 m² of photovoltaic panels cover the roof, and heat is recovered from the pool water and grey water.

Cross section

Longitudinal section

First positive-energy swimming pool in France

“True” BEPOS certification was unattainable for this project, even if 80% of the heat used comes from renewable energy sources and even if 100% of the roof is covered with photovoltaic panels. Yet, the challenge was to demonstrate the pool’s energy performance by means of dynamic thermal simulations and a calculation of water and “physical” energy consumption.

The ideal energy performance goal is around 2,200 kWhep/m²/year. The pool’s total heat consumption is 644 MWhef/ year, i.e. 1,227 kWhef/(m²pool.year). The breakdown of heat consumption is given below:

Heating and hot water consumption

Air handling and static heating

Pool water heating

Fresh water heating

Waste water

DHW for showers

Source : Etamine

Total electricity consumption of the pool is 328 MWhef/year, i.e. 626 kWhef/(m²pool.year). In primary energy terms, this consumption goes up to 1,614 kWhep/(m²pool.year). The breakdown of electricity consumption is given below:

Pool equipment

Air handling

Lighting

Auxiliary equipment

Miscellaneous

Source : Etamine

The commissioning of further equipment will permit the monitoring of numerous indicators in order to analyse and identify possible variations, such as the under-metering of energy and water and the sanitary quality of the air and water.