The research focuses on timber frame structures and their weakness regarding their summer behaviour. Timber frame structures, which represent the established standard of the preassembled wooden made houses of small and medium size, perfectly fit to cold weathers with heating requirements during most part of the year. It is demonstrated that they reach the same thermal characteristic, Uvalue transmittance, with the tiniest thickness of boundary wall. Nowadays, the real technical challenge for these wooden structures lies in hot weather conditions and during summer time. As in the last decades the attention has been focused on the reduction of the heating energy needs in steady-state conditions, the envelope dynamic behaviour has been neglected because it is not crucial in the winter period. At the present time, wooden structures in the Mediterranean area suffer the comparison with heavy brick and concrete buildings. The lower thermal capacity decreases the thermal inertia, speeds the dynamic response and therefore seems to be the main cause of the worsening of the indoor comfort. The direct solution which is the increase of the internal mass up to achieving the required levels will lead to an unavoidable growth of the whole structure mass and thence to a decay of its seismic behaviour. Briefly, the answer to one issue will spoil the main characteristic of the timber structures. The need to find such a solution came up to evidence as the Med in Italy group was chosen to participate to the Solar Decathlon Europe 2012 and both Free University of Bolzano-Bozen and Fraunhofer Italia Research were asked for the energy performance consultancy. According to the main purpose of design strategies, the improvement of thermal capacity across envelope elements has been deeply investigated. The main strategy included an increased mass across walls respecting the lightness of structures typical of wood technologies. Therefore some alternative strategies has been investigated starting from a uniform mass distribution. The use of sand as thermal mass represented a big challenge to analyse different mass typologies.

Timber frame wall with enhanced energy performance - The Solar Decathlon Europe experience

Girasoli , Maria Teresa;
2012

Abstract

The research focuses on timber frame structures and their weakness regarding their summer behaviour. Timber frame structures, which represent the established standard of the preassembled wooden made houses of small and medium size, perfectly fit to cold weathers with heating requirements during most part of the year. It is demonstrated that they reach the same thermal characteristic, Uvalue transmittance, with the tiniest thickness of boundary wall. Nowadays, the real technical challenge for these wooden structures lies in hot weather conditions and during summer time. As in the last decades the attention has been focused on the reduction of the heating energy needs in steady-state conditions, the envelope dynamic behaviour has been neglected because it is not crucial in the winter period. At the present time, wooden structures in the Mediterranean area suffer the comparison with heavy brick and concrete buildings. The lower thermal capacity decreases the thermal inertia, speeds the dynamic response and therefore seems to be the main cause of the worsening of the indoor comfort. The direct solution which is the increase of the internal mass up to achieving the required levels will lead to an unavoidable growth of the whole structure mass and thence to a decay of its seismic behaviour. Briefly, the answer to one issue will spoil the main characteristic of the timber structures. The need to find such a solution came up to evidence as the Med in Italy group was chosen to participate to the Solar Decathlon Europe 2012 and both Free University of Bolzano-Bozen and Fraunhofer Italia Research were asked for the energy performance consultancy. According to the main purpose of design strategies, the improvement of thermal capacity across envelope elements has been deeply investigated. The main strategy included an increased mass across walls respecting the lightness of structures typical of wood technologies. Therefore some alternative strategies has been investigated starting from a uniform mass distribution. The use of sand as thermal mass represented a big challenge to analyse different mass typologies.
2012
9789517585415
thermal characteristics, summer conditions, timber structure, hotbox test
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11392/1678478
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