Category: projects

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Active facade – to protect, collect and redirect

WarmteWinWoning_JanssendeJongBouw

In October 2013 the first ‘WarmteWinWoning’ (free translation: heat-gain-dwelling) has been completed in the Netherlands. A so called ‘WarmteWinMuur’ (heat-gain-facade) has been applied which consists of a prefabricated concrete wall with integrated glycol filled piping. Heat from solar radiation and by convection from the outdoor air is collected by the glycol in the facade and led to a heat pump (1). The heat pump compresses the glycol and the emanating heat is extracted, hereby lowering the temperature of the glycol by approximately 4 degrees. The cooled glycol then is transported to a concrete, thermal buffer underneath the ground floor where it is stored and/or sent back into the wall where it will be reheated (2).  The heat gained through compression is transferred to a low temperature floor heating system (3) and is used to heat water in a boiler that supplies hot tap water (4). The system is controlled by a smart thermostat that ensures a comfortable indoor climate. Because the system responds slow to changes, the temperature is held constant both day and night. According to the developers, for optimal functioning the size of the active facade should be at least 20% of the gross floor area of the dwelling.

The concept has been developed since 2003 when it was tested in a holiday home. In 2008 it has been applied in a daycare centre. Both projects are designed with concrete walls. To make the concept suitable for Dutch housing, where customers prefer the look of brick facades instead of concrete, a prefabricated concrete wall with brick cladding has been developed. In collaboration with Eindhoven University of Technology the wall has been optimized. Because of the temperature changes in the wall, extra dense brick tiles have been firmly attached to the concrete to avoid damage in case of thermal stress. The developers claim that the dwellings can be built in 7 (!) weeks and that the energy bill, when in use, can be up to 45% lower than the bill of a dwelling with a conventional installation concept. More info at Janssen de Jong Bouw.

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Home for life: an intelligent new species

home for life edited

One of the most interesting requests I received while working in building physics has been to evaluate the energy efficiency of the project ‘Home for Life’ according to Dutch energy standards. This dwelling is an example of the active house strategy: the dwelling is energy efficient (even produces more than it needs), creates a comfortable living environment and relates to the local context. A combination of sensors that register heat, CO2 and humidity in all rooms, an outdoor weather station and an intelligent control system ensure a comfortable indoor climate. To optimize energy efficiency a hybrid ventilation system has been applied: the house is naturally ventilated during summer and mechanically, with incorporated heat recovery, during winter. During summer this means saving energy that otherwise would be needed to operate fans. Some more extraordinary measures: when the indoor temperature exceeds the programmed values, windows in both facade and roof automatically open to create a ‘chimney effect‘ which helps reduce the temperature. And automatically controlled solar shades not only exclude excessive heat during hot (summer) days, but are also used to insulate the facade during cold nights to keep heat inside. When focussing on energy efficiency in buildings, designers generally aim to maximize the insulation of  the skin by minimizing the total amount of window area (the weakest link). The quality and amount of daylight within the ‘Home for Life’ however is impressive: over twice as much window area is implemented compared to a standard dwelling. The intelligent building concept manages to enable an exceptionally bright indoor atmosphere  while maintaining a high level of comfort within the dwelling. More info at Active House.