Villa Castelli - Heating / Cooling / Ventilation

Heating and Cooling A heat pump with a geothermal source (3 probes, 80 m deep each) provides heating and cooling as well as domestic hot water. A storage tank allows for buffering demand peaks and integrating waste heat from the kitchen stove. The electricity for the heat pump is generated to a major degree by the PV modules integrated into the roof. This is possible since the heating demand has first been reduced considerably through the insulation of the whole envelope, a ventilation system with heat recovery and the passive use of solar energy through windows (covering 30% of the demand). Ventilation Mechanical ventilation system with heat recovery centralized at each floor, with suspended ceiling. It guarantees a pollen-free, healthy indoor environment and improve the comfort indoor for the users. It controls the air humidity in the rooms, given that the building is lying in a zone closed to the lake. A set of CO2 sensors regulates automatically the air exchanges, and the heat exchanger allows a further reduction of the building energy demands. The mechanical ventilation system is centralized at each floor, in order to guarantee the independency of each flat. Thus, three centralized comfort ventilation units with 480m³/h per unit and a heat recovery of 87% (according to the passive house certificate) were installed.

Heating and Cooling The heat pump itself with the geothermal system does not affect neither the building materials nor aesthetics, as they are not visible from the outside. The PV-system is integrated in the roofing and not visible from outside. Before the heritage authorities approved the PV system, several prototypes were developed for a roof-integrated and preferably invisible installation. The heritage authorities opted for the double-curled aluminium sheet covering of the roof - which is quite common for buildings of this age in a similar way - with integrated mono-crystalline PV modules, folded plates with integrated photovoltaic cells, of about 11 kWp. A sailboat outfitter supplied the extra-thin PV modules. Ventilation - Compatibility with conservation: Integrating the distribution ducts in the ceiling allows to hide them, nevertheless adequate floor-to-ceiling heights are required. - Moisture safety: With ventilation systems high indoor humidity which might induce condensation within the construction at any weak point is avoided. - Energy improvement: A central system for controlled ventilation with heat recovery ensures not only that the necessary exchange of air takes place automatically but also that the incoming air from outdoors is warmed by cooling the exhaust air (the “Air-to-Air Heat Exchanger” recovers up to 85 percent of the heat from outgoing air).