An integrated approach for an historical buildings energy analysis in a smart cities perspective

Currently, the study of the energy performance of buildings is based on a simplified calculation that estimates the thermal loads using monthly or seasonal average outdoor temperatures. In addition, the employed software require technical data such as the specific heat capacity of materials, but at the same time they are not able to properly consider the thermal inertia of buildings. The more precise evaluation allows to assess the correct interventions for energy requalification under a smart cities perspective. This study was performed considering a stationary software (Aermec MC11300) and a dynamic software (TRNSYS). Three simulations considering transparent elements characterized by progressively improved properties of thermal transmittance and solar gain factor have been performed. It has been performed a comparison between the outputs of the two software in order to highlight the different ways of evaluating the energy contributions on thermal loads. Finally, the models were validated by means of an in-situ measurement campaign using a heat flow meter - in order to measure the thermal transmittance of the opaque walls -and a thermographic camera. This modus operandi allowed to appreciate how the use of a dynamic software is more appropriate to deal with the inertial properties of the structure to calculate in a more detailed way the annual thermal loads and to obtain more information on individual heating zones. © 2013 The Authors.