Variability and modularity for envelope retrofitting strategies: a comparative evaluation of the energy performance for multiple design and technical solutions

Energy efficiency in housing is more than a technical problem, since the quality of dwellings deeply influences the identity of a city or neighbourhood. Nowadays a greater attention is given to energy conservation, efficiency in buildings and sustainable design, which also result in the increasing need for technological solutions able to generate energy-efficient improvement in the existing building stock. The energy building retrofitting strategy here proposed aims at tackling the problem of energy retrofitting, by a combination of innovative instruments and tools. The methodology framework is based on the comparative analysis on the performance of multiple envelope solutions that have been tested and combined in different building types in the case study of a large urban district, the Corticella neighbourhood in the north of Bologna. This on going experimental project involves social participation of dwellers in the retrofitting activities; the Architecture Department of Bologna University is working together with the Department of Sociology and Building Physics to set up a direct and active cooperation looking for socio-sustainable solution that can also determine an effective improvement in the energy performance of the buildings’ envelopes. Several design options have been studied for the existing buildings, proposing a structure for expansion and adds-on to be added in different time and space, according to the different users’ needs or requirements, exploring the potential links between technologies and urban dwellers in particular contexts of use [1]. The “Abacus” of possible technologies represents a potential innovative tool collecting all the different design options and determining, for each option, the evaluation in terms of energy performance improvement, cost estimations, cost-benefit analysis, social preferences’ indicators. Keeping into account the high degree of variability of the different contexts and buildings asking for energy renovation, it is suggested to apply a different, integrated approach; the here proposed design research study suggests a multiple and modular system allowing customised and tailored solutions, which would ensure a higher level of adaptability, durability and efficiency. Notably, some of Europe’s leading innovation Nations have included user-driven innovation as a way of providing innovative products and services that correspond better to user needs [2]. Thus, the proposed methodology intends to incorporate in the design process specificities of both building type and users’ needs, searching for the solution that best fit within the specific social and environmental context (tailored retrofitting), by neglecting the use of universal and over imposed solutions and accepting the variability and indeterminacy of flexibility and adaptability, in a longer term retrofitting scenarios.