A Preliminary Check of the Refurbishing Large Office Buildings to a Zero Energy Condition

Abstract

The sustainability in the building industry is currently a trend of the governmental policies in the EU and the USA. In the EU, the target for 2020 is to achieve net-zero energy buildings (NZEB) for the new constructions, as enforced by the 2010 recast Energy Performance Building Directive. On the other hand, it is necessary to make decisions about the technologies to include in buildings when undergoing a major renovation. The aim of this paper is to help to define guidelines about the feasibility of achieving a near-zero energy condition on the existing building stock using the Axiomatic Design theory. Applying this design process to a set of existing office buildings, it is possible to evaluate the energy use of renovated buildings. In the context of this study, the renovation focuses on the reduction of internal loads, isolating the facade and applying new efficient systems in each building. Following the decoupled design matrix of such renovation, it is possible to obtain the fuzzy functions of the energy use. In reality, these functions are the fuzzy sum of contributions to the energy use of the design parameters applied according to the design matrix. The membership function of the energy use allows in turn determining the information content of each type of building, for a design limit of 100 kW·h/(m2· a) of primary energy use. It is found that a renovated building using a photovoltaic system area of about 20% of the floor area of the building allows achieving null information content, or in other words a 100% probability of success.