Energy analysis and HVAC system sizing of a mixed industrial and office Nearly Zero-Energy building

The need to have a more eco-sustainable world has steered our daily practices towards more conscious and rational energy uses. Among these activities, the construction of buildings with nearly zero energy need and the renovation of the existing ones can certainly have a large impact from an energy standpoint. In this direction, the "Energy Performance Building Directions" (EPBD) of 2010 defines the concept of a nearly zero-energy building (NZEB), although the requirements to qualify as NZEB remain ambiguous. In Italy, the NZEB concept is strongly related to a major use of renewable energy sources to cover the energy demand of the buildings. In this regard, non-residential buildings represent an important challenge, especially when old industrial structures, built when energy efficiency was not a primary issue, need to be converted to other uses and comply with the NZEB requirements. This work refers to a building of this kind, a disused industrial structure from 1959 in Corso Orbassano in Turin. SIGIT, a manufacturer of plastic and rubber components, has planned to redevelop the building and turn it into its directional and operative headquarter, the Innovation Square Center (ISC). The structural and aesthetic renovation has been entrusted to the architectural firm SeArch, while the design of the new HVAC plant has been assigned to Ferplant s.r.l. In order to preserve the original concrete structure while complying with the normative requirements, interventions on the envelope of the building are limited to the change of doors and windows, and on the addition of insulation coatings on walls, floors and ceiling. Given this, the HVAC system has to be designed in the most efficient way to guarantee the compliance with the requirements for NZEB. This work addresses this issue and analyses the optimal sizing of the plant by resorting to both a semi-static evaluation using the software Edilclima and a dynamic simulation carried out with the program DesignBuilder. The results of the two models, in terms of power and energy consumption, are then compared to understand the factors that could potentially cause a dissimilarity in the values of the calculated energy needs. In addition, to better understand how to achieve energy efficiency, in a further analysis two different air-conditioning configurations in one important space of the building are evaluated. In addition to Edilclima and DesignBuilder, other software packages are used: -??SketchUp, to draw the 3D model of the building to be used in DesignBuilder, and Open Studio plug-in to define thermal zones; -??THERM 7.6, to model two-dimensional heat-transfer effects in a building component where thermal bridges are of concern. The thesis was carried out at Ferplant s.r.l offices, based in Chivasso (TO).