The dual influence of the envelope on the thermal performance of conditioned and unconditioned buildings

Cities are progressively widening, incorporating rural and industrial zones and, at the same time, largest cities often need conversion of entire neighbourhoods. The transformation of large areas, through the introduction of energy-efficient buildings, quickly provides economic and social benefits. The current technologies for building energy-saving offer wide technical solutions range mainly developed for residential buildings. Nevertheless, the current literature lacks enough studies on envelope effectiveness in non-residential sectors, where indoor conditions are considerably different from residential. In this context, the paper aims at assessing the influence of five architectural characteristics on the thermal performances in a case study food-processing building. 576 building configurations are analyzed for six different intended use (0–24 °C) in conditioned and unconditioned scenarios. The performances of the different building configurations are expressed in terms of energy need (conditioned scenario) and thermal discomfort (unconditioned scenario). Results reveal that building thermal performance is connected to temperature ranges and the same building envelope characteristic can show positive or negative contribution according to the simulated scenario. Finally, for both scenarios, the most influential architectural characteristics have been identified and evaluated. Moreover, the paper proposes a methodology for building energy assessment for the transformation of existent industrial food-processing buildings in urban and suburban areas.