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I like it, but how much power does it use?

* Author: Miguel Ángel Menéndez *

You often listen to customers at dealerships asking what a vehicle’s fuel consumption is. However, this does not happen in the real estate sector. On very few occasions have I come across this question during potential customer visits to the estate agent’s.

But it seems that we are approaching a new paradigm, as Directive 2010/31/EU of the European Parliament on energy efficiency of buildings is going to change our perception of what we considered an efficient building up to now.

I believe that the global energy and climatic context will bring about a significant increase in energy efficiency that will put the oil crisis of the 1970s into perspective. Thus, and taking into account that the tertiary sector accounts for around one third of total energy consumption in our country, of which more than 50% corresponds to office buildings, I would like to take advantage of this post to explain how Iberdrola Inmobiliaria is carrying out the Porta Firal project in Barcelona.

Porta Firal is the most ambitious private development tertiary project undertaken in the city of Barcelona and will provide space for four office buildings. Our first building under construction, T3 Tower, has a final energy consumption of 31.2 kWh/m2 year, 70% less than a reference building, and its level of emissions has been reduced to 16.1 kg CO2/m2 year, nearly 75% less than a standard building. These improvements have enabled us to achieve high energy efficiency Certificate A under Royal Decree 47/2007.

How have we accomplished this? Firstly, through MIYABI (energy efficiency in construction), a public company set up by the Regional Government of Navarre we have partnered with in order to model the building using two computing tools: Energy Plus, developed by the U.S. Department of Energy, which is capable of simulating full life cycles of a building considering all the variables which are relevant to its energy performance, and Calener GT, the official program for energy certifications.

In order to meet the demand for the building’s air conditioning and hot water we chose an Ecoenergies system. Once the equipment for the building was determined, we performed an energy simulation. The result obtained for final consumption was that nearly 65% corresponded to lighting and 22% and 13% to ventilation and air conditioning, respectively. This data differs from the figures for a standard building, which shows that 28% corresponds to lighting, 30% to air conditioning and 20% to heating.

We thus identified a clear need for increasing efficiency in lighting, a problem that combined with the handicap of having to meet the requirements set out in the Technical Code, which for a building with these characteristics required the installation of 35.1 kWp in photovoltaic solar panels. We had to locate then on the roof at a height of more than 92 metres, with a very limited surface area and, taking into account that this type of installations are currently not cost-effective, we embarked on negotiations and analyses with the Barcelona Energy Agency.

We approached the problem in two ways: façade treatment and equipment efficiency. The results were conclusive: for the same investment cost, the installation of the photovoltaic solar panels would have generated 79,830 kWh/year of electric power, whereas the measures taken in this project for increasing the efficiency values and improving the optical parameters of the window glazing achieve a reduction of 517,284 kWh/year, representing a saving in final energy of 437,454 kWh/year on the photovoltaic solar installation.

Iberdrola Inmobiliaria decided to implement this type of buildings in order to support the technological and sustainable commitment of the parent company, Iberdrola. Thus, thanks to the promotion of sustainable construction and energy efficiency, the Porta Firal project, which has received maximum energy efficiency certification, will become a reality in 2013.

Author: Miguel Ángel Menéndez

Bio: Architect and Executive MBA from Esade. I started out in the construction sector with my father, carrying out indoor installations. With him I learned that each project needs to be tackled as a challenge and that despite the difficulties you may find along the way, perseverance and faith in a job well done always yield results. Once I completed my studies, which I combined with work, and after years of sacrifice, I was lucky enough to participate as project manager in emblematic projects with great architects like Rafael Moneo, Richard Rogers and Arata Isozaki. It is a privilege to be part of the Iberdrola family and be able to take part in the most important project of its real estate subsidiary.

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