دانلود رایگان مقاله عملکرد هیگروترمال یک ساختمان کاه بیل

Abstract

This paper focuses on the assessment of the hygrothermal performance of a straw bale house in the Picardie, a region of France. The house was built using a wooden load bearing frame filled with straw bales. Laboratory and in situ tests were carried out in this study. In the first part, the thermal conductivity of straw bales was measured in relation to the orientation of the straw fibers. The thermal resistance of a wall built in the laboratory, respecting the real construction parameters, was assessed. The obtained U-value was compared to those of different walls used in civil field engineering. The second part of this paper continues with an assessment of the hygrothermal performance of a real straw bale house. Temperature and relative humidity measurements were recorded during more than one year, using sensors that were placed in indoors and outdoors, and at various depths of the walls and floors. Finally, this paper is completed by a dynamic thermal simulation of the house, based on experimental laboratory investigations. During winter the simulated heating requirements are estimated at 59 kW h/m2. Moreover, the simulation under summer conditions shows the major influence of the building envelope on the thermal comfort. Thus, straw bale walls seems to provide significant thermal inertia in summer.

5. Conclusion

This study provides an in situ analysis of the hygrothermal performance of a straw bale house built in Picardie (France). The experimental study was completed by laboratory investigations. The measurement of thermal conductivity of straw bales (as function of the orientation of the straw fibers), as well as the assessment of thermal resistance of a straw bale wall similar to those constructed for the real house showed the insulation power of this bio-based material. In situ measurements of temperatures and relative humidity showed the hygrothermal performance of the building envelope. The temperature and humidity profiles, recorded at various depths of walls (north- and south-facing), revealed that there was no condensation risk in the straw bale walls. In addition, the influence of the limeplaster coating on the protection of straw against mold appearing at a high moisture content was highlighted. The indoor temperature and relative humidity recorded showed that the material can provide excellent living conditions which have been confirmed by the occupants. A dynamic simulation of the thermal behavior of the straw bale building, based on experimental results measured in laboratory, has been carried out. The numerical results confirmed that using straw bale material can ensure a good thermal performance and a high thermal comfort.