The paper presents experimental measurements and numerical simulation of thermal environment in naturally ventilated room by a fresh air valve. For the aim of Computer Fluid Dynamics (CFD) simulations, a model room was created. The fresh air valve is located in an occupied space, at the external wall. It has a major effect on mixing indoor and outdoor air, temperature profiles, thermal condition and indoor air quality of the rooms during the heating period. To determine the thermal condition of a naturally ventilated building, PN-EN 15251:2012 standard was used. According to the standard, using PMV/PPD is suitable for evaluating the thermal environment. In the naturally ventilated buildings, the following criteria are very important for local thermal discomfort: draught, radiant temperature asymmetry and vertical air temperature differences. To compare the simulation results, real air temperatures were measured by the thermocouples in a day room having the same geometry. A series of simulations has been carried out to determine the profiles of temperature and velocity of indoor air. Obtained results prove correlation with calculations of profiles of indoor air temperature, estimated using the thermocouples.
Hemp-lime composite is a thermal insulating material used as a filling in timber frame construction walls. It is a material based on the wooden part of industrial hemp stalk (hemp shives) and lime binder. In practice, different wall thicknesses, composites with different thermal properties and various configurations of timber structure are used. These factors affect the temperature distribution in the wall. In the thermally weaker areas of walls, there is a greater risk of condensation and mould growth. This issue is important while designing walls based on organic materials. The paper presents the two-dimensional (2D) heat-transfer analysis based on the finite-element method, using THERM software. Several variants of external walls were adopted for the analysis. Thermal parameters of hemp-lime composites used in the analysis were obtained from our own research. The results of the analysis were presented as the values of the thermal transmittance coefficient and linear thermal transmittance equivalent to timber construction. The temperature distribution for an exemplary wall was also shown graphically in the form of isotherms and colour-flooded isotherms.
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