About 20% of energy consumption around the world is used for maintaining a comfortable indoor climate. Developing materials that respond to diurnal humidity/temperature changes would be highly promising for energy-saving buildings. In this work, we report on “Transpiring Wood” by laser-drilling microscopic holes perpendicular to fiber direction and incorporating a hygroscopic salt (calcium chloride) (Figure 1) [1]. The resulting wood composite displays superior water absorption capacity and high moisture exchange rate. By exchanging moisture with the surrounding air, Transpiring Wood is able to efficiently regulate indoor humidity and temperature for living comfort. The reduction of temperature fluctuations can lead to an indirect energy saving of about 10% for cooling and in the range of 4-27% for heating, depending on the climate conditions. We proved that the hygrothermal performance of Transpiring Wood can be used for passive indoor climate regulation in various climate types. Moreover, our Transpiring Wood showed low environmental impact due to sustainable raw materials and green fabrication processes. These findings open the avenue to produce energy-efficient building material with sustainability, moisture capacity, moisture exchange rate, and mechanical integrity.
Keywords: hygrothermal effect, moisture buffer effect, thermal energy storage, passive regulation system, energy-efficient building materials, life cycle assessment
Authors
Yong Ding
Wood Materials Science, Institute for Building Materials, ETH Zürich, Switzerland
WoodTec Group, Cellulose & Wood Materials, Empa, Switzerland
Christopher H. Dreimol
Wood Materials Science, Institute for Building Materials, ETH Zürich, Switzerland
WoodTec Group, Cellulose & Wood Materials, Empa, Switzerland
Kunkun Tu
Wood Materials Science, Institute for Building Materials, ETH Zürich, Switzerland
WoodTec Group, Cellulose & Wood Materials, Empa, Switzerland
Tobias Keplinger
Wood Materials Science, Institute for Building Materials, ETH Zürich, Switzerland
WoodTec Group, Cellulose & Wood Materials, Empa, Switzerland
Guido Panzarasa
Wood Materials Science, Institute for Building Materials, ETH Zürich, Switzerland
WoodTec Group, Cellulose & Wood Materials, Empa, Switzerland
Ingo Burgert
Wood Materials Science, Institute for Building Materials, ETH Zürich, Switzerland
WoodTec Group, Cellulose & Wood Materials, Empa, Switzerland
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