Power Air Conditioning is Out
Power Air Conditioning is Out
According to the usual formulas for art institutions found in technical literature, the Kunsthaus should have been conventionally air conditioned for an anticipated 25 million Austrian schillings. 25,000 cubic meters of air would have been blown into each of the four exhibition floors. The analysis was based on conventional approaches to ventilation, the “power air conditioning” customary in such cases. In view of the significantly more favorable overall cost of air-conditioning, Peter Zumthor implemented a re-planning of the air conditioning concept by Meierhans and Partner. The company was tasked with ensuring that all issues could be solved with half the investment costs and only a fraction of the energy and operating costs.
The New Basic Principles
Using these requirements and guaranteed values, the planning was based on the following principles of modern air conditioning engineering:
1. Active mass coupling and component heating / component cooling:
not the air, but the building’s mass is thermally controlled and ensures the desired indoor climate.
High quality insulation ensures the decoupling of external influences.
Circulating heating and cooling water controls the temperature of the building’s mass.
2. Basic ventilation and space coupling:
Air is only employed to air the spaces. During peak loads, the unused air present in the building is also taken into account as thermally driven natural ventilation. Humidification and dehumidification are limited by minimizing the in-flow of external air.
Basic ventilation (air conditioned): 750 m3/h and floor.
3. Decoupling sources of disruption:
The exhibition spaces with their light-filled ceilings are conceived as two-zone models. In the upper zones, the more disruptive, dry heat sources of daylight and artificial light are the major influence. In the lower, climatically sensitive areas, the less problematic heat sources, that is visitors, are more easily controllable. Humans possess the practical property of not only heating but also humidifying the air: they interfere negligibly with the relative room air humidity.
4. Mass coupling and earth coupling:
While the "downsizing" of conventional climatic technology is based on these first three principles, we were able to make use of the benefits of the location of Kunsthaus Bregenz in the fourth principle, the earth coupling: the constructional diaphragm wall around the basement stands 25 m deep on solid rock. It is surrounded by ground water flowing from the nearby Pfänder uplands into Lake Constance. Regional construction has been using this property as a source of heat for heat pumps for decades. Diaphragm walls and foundation piles are covered with plastic pipes conveying water, being used for environmentally friendly, renewable energy production. The Kunsthaus uses it for cooling.
Cooling cycle using earth coupling, heating cycle using a gas boiler
The building’s double layered glazing, its flexible external sun protection, and its very good external insulation offer the best conditions for future air conditioning concepts: buildings of this type effectively no longer need to be heated, but are cooled more or less all year round. However, this is no longer done with cooled air and with 6-degree water from a cooler, but with building component cooling and with virtually room temperature water, which cools naturally within the diaphragm wall.