Near Zero Energy Historic Building. Tools and Criteria for an ecocompatible and ecoefficient conservation

To set conservation project in sustainable human development means to understand in-becoming reality, turning the static vision into a dynamic approach that considers life cycle as theoretical-methodological base, articulated in different and integrated steps. Historical architecture, in Mediterranean basin, assumes a type-morphological structure in coherence to microclimatic characters of site, defining the optimization of energetic relationships with surrounding natural environment. Interventions on historical building, therefore, cannot put aside from the articulation in subsystems of the components constitutive the object on which operate, individualizing: - environmental context, conditions of state defined by natural/artificial characters of site - settlement system, typological-morphological, physical-spatial and setting characters of the structures of built environment - building organism, organizational, distributive and conformed characters of architecture. The building – as fluid, adapted, sensitive interface, superficial border line that is able to define the relationships with environment and to model itself on environmental factors – finds in technological environmental design tools and criteria to make a dialog with climate and natural elements: sun, wind, light, water, vegetation are materials and sources of energy that the project makes to selectively interact with the context, in a continuous exchange of material and energy, determining an equilibrium of transformations. Transferability of bioclimatic approach (systems and technologies) to the "planning of the existing heritage" allows to re-construct the processes of "natural working" of the historical-architectural structures, valorising characters (orientation, radiation, shadowing, form and compactness, peculiarities of envelope and characteristics of materials) in the microclimatic local conditions, inside the landscape, to increase environmental efficiency. The objective of the compatibility among demands of protection, exploitation and fruition shapes the intervention “on the existing” as insertion of the new (low energetic systems and equipment for preservation and fruition) within the "ties" imposed by the historical envelope - system of constructive elements that separate indoor space from outdoor environment - that constitutes the principal vector of exchanges. The "third skin" of building, therefore, is set as priority operational field - through components and materials analysis - to control biophysic and bioclimatic factors that cause alteration and degrade of surfaces; to ensure captation, accumulation, distribution, protection, dispersion behaviours; to integrate devices and systems for indoor environmental comfort; to introduce green and water into in-between spaces; to adopt elevated ecological compatibility materials, finishes and treatments