Development of a low-cost movable hot box for a preliminary definition of the thermal conductance of building envelopes

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/(m2 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.