Development of a low-cost movable hot box for a preliminary definition of the thermal conductance of building envelopes. (August 2020) - Barbaresi, Alberto
Abstract: In the recent years, very promising envelop solutions are available for energy-efficient buildings. Particular interest is risen by the use of innovative natural or bio-based materials. Even if, in some cases, they are wastes coming from industrial or agricultural processes, they can be effectively applied as by-product for the creation of new more sustainable insulation panels and composite materials. In this context, the thermal characterization of a new building material, actually needs of very expensive equipment, with fixed installation, requiring expensive usage and periodic calibration and maintenance. Development of alternative methodologies to determine thermal properties, even in a preliminary way, seems important in order to reduce the costs and to make the tests accessible to wider number of researchers. This paper describes the development and the validation test of a low-cost movable hot box suitable for a preliminary assessment of the thermal conductance of wall elements and insulation panels with dimensions about 1 m × 1 m. The prototype of the hot box has been realized and then tested in the conductance range 0.5–10 W/(m 2 K) by adopting two commercial panels used in the building sector. The availability of a low-cost, low-size and moveable equipment allowing a quickly and preliminary assessment of the thermal characteristics of a by-product is useful to understand if the material has suitable properties for future re-use. All this allows the reduction of laboratory time and costs needed for the thermal characterization tests. Highlights: The paper describes a new hot box for thermal conductance characterization. The reduced dimensions and temperature cycles make it remarkably cost-effective. It can provide reliable preliminary results with cost-effective tests and reduced time. It is useful to test materials in different configurations or when supply is expensive.