Fátima Maria Gomes Jardim - Universidade do Minho

Proposal for Rehabilitation Building Energy Housing
Abstract
The waste of energy is one of the factors of greatest impact on the environmental imbalance
that the planet is facing. Currently, in Portugal the buildings’sector consumes approximately 31%
of the final energy used in the country, standing as the most important sector, immediately after
transportation. Of this amount the household is responsible for about 18% of the consumption,
contributing significantly to the emission of greenhouse gases. The energy consumption depends
on many variables, but we can say that the principal component results from the everyday use of
the buildings. Overall, the consumption comes from two conditions: intensive installations (heating
and cooling, lighting, equipment, etc.) and an extremely dissipative behavior of the buildings
(buildings without insulation or without thermal inertia).
The housing Portuguese currently outstrips the 5.5 million dwellings, so the potential savings
in this sector is very significant. This work was the study of energy rehabilitation of existing
buildings by reducing energy consumption through measures to enhance the thermal
environment. In fact although there is no requirement for owners to carry out works, with a view to
improving the energy performance, this work demonstrates that there are objective advantages
that can make that decision quite favorable. One of the arguments will be the most decisive
evidence that the initial investment is recovered over a relatively short time, considering the
lifespan of buildings.
To understand the importance of rehabilitation energy two case studies were used as
representative of current construction, housing, practiced in Portugal in recent decades. The
methodology addresses the work of characterization of the energy performance of existing and
accurate diagnosis of the deficiencies presented by proposing solutions for thermal rehabilitation
and energy, knowing if they reduce energy consumption to the point of becoming economically
and environmentally sustainable. Adopted the methodology used in the current simplified RCCTE.
We considered variations of reinforcement and insulation thickness to perform simulations at
fractions considered more demanding. Thus, it is possible to investigate the interdependence of
various parameters and establish benchmarks. The results showed that through the
implementation of rehabilitation measures, we can achieve remarkable savings of energy
consumed for heating. The study notes that investment in upgrading energy efficiency building
should be done case by case basis, through a rigorous assessment of energy consumption of
each fraction. Finally we developed a financial model that provides the weather forecast for return
on investment, along with analysis of the benefit cost ratio to realize the return on investment
compared to the total savings in energy consumption.
Keywords: Efficiency, Rehabilitation, Thermal, Sustainability
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