Design choices and thermal simulations of a new test cell facility

The paper presents a new test cell facility, named Box Office and under development at the Ecole Spéciale des Travaux Publics (ESTP Paris) for the analysis and characterization of the thermo-physical properties of building envelope components under real climate conditions. The facility will allow to obtain reliable estimates of thermal performance indicators of transparent and opaque building elements. Particular care has been taken in the design phase in order to minimize or to monitor all sources of uncertainty, such as (i) conductive heat losses through the test cell envelope, (ii) time lag of response to transient outdoor conditions, (iii) levels of airtightness and of resistance to vapour or water penetration. Highly variable solar conditions can seriously affect both the correct functioning of outdoor test facilities and the indoor climate conditions in the cell. For this reason, the thermal behaviour of the Box Office was simulated in Matlab environment, implementing a lumped-parameter model, and results are used for refining the design choices and selecting the most promising operative conditions and control strategies. The output of test cell experiments will be beneficial to various target groups, such as designers and manufacturers (to boost the research and development of new products), research centres (to fully understand and model the physical phenomena occurring in a controlled space facing real outdoor conditions) and potential clients, who ask for economically affordable solutions guaranteeing high levels of Indoor Environmental Quality.