The challenge in terms of sustainability:
The building concept by the Dutch architect Jon Kristinsson was intended to prove that sustainable construction – as well as the juxtaposition of people and plants – has potential for urban development of the future, and that sustainability can be effectively implemented to protect the environment.
The initial situation:
Villa Flora was created for Floriade 2012, the World Horticultural Expo, held in Venlo (Netherlands). The complex consists primarily of glass, steel, concrete, and wood, and has a modular design with the result that these long-life elements can be later used for other buildings (the cradle-to-cradle principle). The building ensemble consists of a giant greenhouse with exhibition floor space, and an attached office building. Despite the extensive glazing of the structure, the building was designed to be climate-neutral and cost-effective.
The resulting combination of a greenhouse and an office building is a pioneering achievement from the energetic standpoint and is CO2-neutral. To heat and cool the building, an underground long-term heat-storage system with two dual-well systems goes into action, in combination with HVAC systems from DencoHappel und GEA Refrigeration Technologies. The building ensemble is cooled in summer by pumping cold water out of one well in the upstream well system. Via fan coil units (see Fig. 2: the Flex-Geko® units installed in the glasshouse section), the cooling water absorbs heat from the building and stores the heat in the second underground well. Until the following winter, this water will flow about onehundred-fifty meters to the second well system, from which it is removed for heating purposes. Since the water is not yet hot enough for heating, a heat pump raises its temperature to a usable level. The relatively high temperature in the well means that the heat pump can operate with extremely great efficiency: at Villa Flora, the coefficient of performance (COP) of the compressor is 7 ... 11. This means that one kilowatt-hour of electric power can create eleven kilowatt-hours of heat. An additional reason for the outstanding efficiency of the heat pump is the refrigerant used: ammonia (NH3). This natural refrigerant has no ozone-depletion potential and is highly energy-efficient.
CAIR® air handling units assure hygienic air-exchange. In the office rooms, air is supplied through outlets in the raised floors, which also serve for underfloor heating and ceiling cooling. Phase-change materials (PCM) provide internal temperature compensation in the air handling units.
The electric power for Villa Flora – and for operations of its heat pump – comes from solar panels. In addition, elevators generate power as they move downward. The remaining needed power comes from green sources.
The sustainable strengths:
Villa Flora is not only CO2-neutral: its surplus heat production is also sufficient to cover the heating requirements of “The Innovators,” the neighboring building. As a result of systematic application of energy-saving technology in Villa Flora, and of its overall positive energy balance, its utilities and incidental expenses (often called the second rent) are low.