Bioclimatic Architectural Design: the architect s contribution to energy saving

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1 Bioclimatic Architectural Design: the architect s contribution to energy saving One of the greatest challenges of our time is to save energy, especially in the building sector, which is responsible for 40% of total energy consumption in the European Union. And yet in Greece, which has particularly high levels of sunshine (from 2,200 to 3,100 hours per year for various regions of the country), one can see glass high-rise office buildings with no protection from sunlight and overheating. Or residential buildings that have inadequately shaded outdoor spaces (porches, patios) or that are oriented towards the north, having their "back" turned to the beneficial southern light. It is most certain that the sight of all those unsuitable for our climate -and therefore inefficient- buildings would have puzzled the experiential architectscraftsmen of our country in the previous centuries. They had not graduated from any university, still they knew how to build buildings adapted to the microclimate of the area and to the needs of their users. First one to apply this was the ancient Greek philosopher Socrates, who gave instructions about the construction of his Solar House, back in 470 BC. Modern architects that apply the principles of bioclimatic architectural design in their studies, attend to recall this wisdom found in buildings all around Greece; houses in Athens (featuring inner courtyards and sun porches), chateaus in Mani, mansions in Macedonia (featuring enclosed balconies) and cave houses in Santorini. Socrates Solar House - contemporary illustration Source: G.P. Labba, Architect academic House at the Athenian Agora of the 5th century BC. Source: I. Travlos, Urban Evolution of Athens, Athens 2005 Sun porch at a house in Athens, Greece Source: A. Konstantinidis, Old Athenian houses (1950) The Bioclimatic Architectural Design borrows several elements derived from the traditional architecture, formed by years of empirical knowledge. Thus, modern architects need to design according to the local climate and not against it, just like traditional craftsmen have done for centuries before him. Bioclimatic Architectural Design seeks appropriate solutions in order to achieve a balance between: The design of the type of the building s envelope and its construction.

2 The climate and location of the building s plot. The needs and life style of its residents. Bioclimatic Architectural Design (whether it is referring to a building or a whole neighborhood) depends on local climate. Its purpose is to adapt the building and its outdoor space to the climatic and environmental conditions of the plot s region rather than trying to adapt the environment to the building. Furthermore, it uses all these parameters (such as solar and other environmentally friendly energy sources) for the building s benefit and, at the same time, also protects the building of their adverse effects. Bioclimatic Architectural Design referring to a building aims to: 1. achieve thermal protection of the building (thermal insulation, airtightness) 2. take advantage of solar energy in winter time (allocation and orientation of the building, proper construction of building s envelope, correct sizing and arrangement of spaces and exterior doors/windows) 3. protect from sun & heat in summer time (natural / artificial shading and careful planning of deciduous & evergreen vegetation in the building s surrounding area) Insolation during summer and winter solstice, source: ARCHITECT-LAB, Nasia Roditi 4. protect from the wind in winter time (allocation of building s volumes, vegetation in the building s surrounding area) 5. take advantage of the wind in summer time (natural night ventilation to remove the heat stored in the building during the day, correct sizing and direction of exterior doors/windows)

3 Natural ventilation using small high windows, source: ARCHITECT-LAB, Nasia Roditi 6. the proper use of the building materials characteristics (thermal mass, reflectivity, absorbency, etc.) 7. the adequate natural lighting (distribution of light inside the building, control of solar radiation) 8. the overall improvement of the microclimate around the building, which also has a great influence on the interior thermal comfort During the previous centuries, the only heating source to be found in a building was the sun and fireplaces (with the exception of the Palace in Knossos - Crete, where a floor heating system operated already since 1700 BC!). The only cooling system available was natural ventilation and vegetation on the outdoor spaces. People knew how to adjust their needs and their buildings to the climatic conditions of the building s site and also used local materials. With absolutely no additional construction costs, since it was only a matter of proper design, they managed to have free energy for the heating and cooling of the building. Cave houses in Santorini Cyclades, Greece source: travelstyle.gr The chateaus in Vatheia, Mani Peloponnese, Greece source: tresorhotels.com Enclosed balconies in a mansion in Kastoria Macedonia, Greece source: kastoria.gr

4 Over the years, building methods have changed; stone masonry evolved into reinforced concrete or metal frame. New technologies and new materials give us unlimited design options for the external envelope of the building. In addition to that, modern windows, thermal insulation materials or sophisticated electromechanical systems for heating and cooling protect the building from the local climate s adverse effects. During the last century, our needs and life style have changed too. A nice view and ample natural light indoors is not negotiable any more, even when building in plots with adverse climatic conditions (e.g. a panoramic sea view may be accompanied by strong winter winds). Furthermore, the rise in number of residents in cities leads to tight housing complexes that alter the local climatic conditions. At the same time the increased use of "hard" materials in buildings and public spaces (e.g. concrete, asphalt) further complicate this situation (overheating in summer, containment of the beneficial summer winds and floods in winter). Bioclimatic architectural design principles of a study of a Passive House private residence in Loutraki - Greece source: ARCHITECT-LAB, Nasia Roditi

5 Trying ever so hard to improve our living conditions (which we deteriorate ourselves!) we use energy sources with an expiration date; such as oil, natural gas and other fossil fuels. Fortunately, the exploitation of renewable energy sources has been constantly evolving in recent years (solar - photovoltaic, wind - wind generators), but still only to meet our energy needs that are artificially inflated. Is it not time to set a target to reduce our energy needs by means of designing bioclimatic buildings and cities, rather than looking for ways to increase the energy production? Indicative section of preliminary study of a bioclimatic school in Crete, Source: ARCHITECT-LAB, Nasia Roditi Without major restrictions on our desires and needs as users and residents of buildings, we can reduce their energy consumption in a smart way; using the principles of Bioclimatic Architectural design. Let s "Return to our roots" then! This is the architect s contribution in energy saving, completely free of charge! Athanasia (Nasia) Roditi Architect Engineer NTUA Πηγές: 1. Iro Benessaia, Architect Engineer DPLG, Bioclimatic Energy design Course, Athens 2011, Technical Chamber of Greece 2. Α. Mantzarakis, Β. Katsoulis, Duration of daylight hours in the Greek area, 11/2005, 7th PanHellenic (International) Conference of Meteorology, Climatology and Atmospheric Physics /31/EU Directive of the European Parliament and the Council of May on the energy performance of buildings