Although passive solar heating and solar energy in general are major subjects of “sustainable architectural design”, orientation towards the sun, which is an inseparable issue related with them does not seem to take part much in discussions about sustainability. I want to discuss the reasons why orientation of buildings can be unpopular or somehow forgotten.
Generally, the orientation of living spaces to south-southeast (of course on the northern hemisphere) is a well known issue. It is also well known that the orientation of any building block, on the east-west axis, which means longer side towards the south where the sun rays are less inclined and shorter sides to the east or west where the sun rays are more inclined. Another well known point is that the afternoon sun from the west is very negative in terms of cooling buildings and spaces, especially in hot climates. Also horizontal sun breakers or eaves designed according to differences of inclination in summer and winter are essential in sun control when dealing with southern transparency. When a linear block is oriented towards south, this also means that it is oriented to north on the other side. In temperate climates, south-southeast or southeast orientations are preferred as the other facade would also get some direct sunlight from the northwest. Southeast can also be more favorable in colder climates to provide more radiation in the morning hours. In hotter climates, southern transparency may be more limited, where north becomes more preferable for living spaces, calculating good proportions for courtyards to create better “cool air pool” solutions. Not to get into more detail about variations of climatic conditions, I want to stop here and concentrate on the temperate zone in my discussions.
As far as we know, the idea of orientation of buildings towards south is first apparent in the teachings of Mies van der Rohe in the Bauhaus. Various examples from Bauhaus studios show examples of houses where living rooms are directly exposed to sunlight from south and southeast and exposure to west is intentionally limited.
Student work from Mies studio in Bauhaus, Haus eines musikfreundes Josef Pohl 1933
We can note here that the city planning before modernism is very formalistic to be concerned with sunlight. In the traditional architecture there was no opportunity to choose the general orientation of buildings because the urban morphology has taken shape in more complex procedures. Coincidentally there may be towns with south exposure, which somehow become famous with their good climate and nice view of moonlight.
While Bauhaus was practicing the first ideas of sustainable site planning, not very far, in France Le Corbusier had started from a very formalistic approach. His first high rise cross plan housing blocks were supposed to allow airplanes to pass in between. Although Le Corbusier had a very interesting urban development project for Zlin in former Czechoslovakia where all the building blocks were placed in north-south exposures, he later changed his mind to place his linear blocks in the opposite direction. Because he insisted on double loaded apartments for the sake of economy, he decided to divide the sunlight for the two facades. But he did not give up the few apartments at each floor with south orientation. He somehow created a confusion where anything goes except north. Contrary to his great mastery of colors and forms, which he thought architecture as a play of them, his functional planning was not always logical, even sometimes contradictory.
Another approach can also be mentioned as the north exposure philosophy, departing from the various problems caused by direct sunlight. The diffused light from the north would be ideal, as in a sculptor’s studio. This idea was also widely utilized in northern countries, where huge glazed facades were faced towards the north without any good insulation.
After education in Bauhaus was interrupted by the Nazi regime and the World War II, this idea of orientation towards south seems to be almost forgotten. Idea of sothern orientations seems to remain a marginal attitude conducted by some of Mies’s students like David Haid and Alfred Caldwell at IIT and may be a few other places. Le Corbusier’s ideas seems to have higher international recognition, as especially seen in the works of Niemeyer. However the idea of arranging new settlements with linear blocks, following Hilberseimer seems to create some examples at the risk of being monotonous. Where all the blocks had the same orientation, there was an obvious problem of monotony implying totalitarianism. Probably it became easier to combine the two different orientations in one project to end up with seemingly a brighter solution to depart from totalitarianism, as in Parisian suburbs, as well as in the Eastern Block. It is said that the Yugoslavian experience facilitating the ability of constructing more blocks from a single position of a tower crane was also supportive of a different orientation policy.
Paris banlieus, HLM housing in Cité d’Orgemont, Épinay-sur-Seine
At this point i want to speak about my very personal observations from various plattenbau (as they are called in Germany to define the most disturbing urban problem) related with the north-south exposed linear blocks are well maintained, keeping their economical values in various places of the world, including Istanbul. On the other hand the east-west oriented blocks seem to create various problems as of heating in winter, as well as excessive heat gain in summer, generally ending up with the difficulty of sun control.
In 1963 a very interesting book was published to gain worldwide recognition named “Design with Climate” by Victor Olgyay. This book, in a short time became the bible of 70’s architecture, we can say, focusing on environmental concerns. Olgyay’s book, in a very direct and open way, explained the disadvantages of west-east exposures and the advantages of south orientation with the very basic idea of sun control with an eave, describing the inclination of sun rays in summer and winter. Everything becomes very clear once again, this time in a more scientific way, to define the principles of the passive solar house.
70’s was also the years of energy crisis, where the inefficient glass architecture with a confused mind was surely an aspect of this. I am thinking that the architecture world confronted this crisis with a very interesting movement called post-modernism, which re-introduced the square windows again, together with Le Corbusier’s longitudinal window.
After Olgyay we know more about the correct orientation of buildings but can we say these principles have been applied to architecture in an effective way? I think the answer is no and the reason seems to be the problems related with the conditions of the site. What can an architect do if the site forces the architect to west exposure? For most of the architects to deal with the orientation of buildings would be too idealistic. Of course an awareness is raising with the sustainability and green building culture. I would like to note the name of the Australian master Glenn Murcutt here, who is I think one of the exceptional architects, very sensitive to orientation and sun control.
This fact about the site conditions will bring us to another level of urban design or physical planning, if a city can be planned to create a more environmentally sensitive, sustainable architecture in terms of orientation towards the sun? This is of course more possible in planned new settlements.
When we compare new capital cities we can observe different attitudes towards orientation. Ankara’s new plan by Hermann Jansen, a follower of the garden city movement in the 30s, was confronted with a long axis in the north south direction, the road to Çankaya, later to be named the Atatürk Boulevard. Jansen’s stadtebau school from Germany, was quite unaware of the idea of orientation of buildings. Ankara’s new buildings suffered from exposure to west, with Jansen’s planning using parallel streets to this main axis. The new plan for Brasilia was totally disregarding the problem of orientation, with the formalist “bird wings” scheme by Niemeyer, probably who was following Le Corbusier’s confusions. The much socially criticized planning for the Capitol of Chandigarh surprisingly displays a different attitude to orientation. The Secretariat is oriented in southeast-northwest directions. Le Corbusier’s squareish Roman grid offers possibilities of a southeast oriented architecture. However the arrangement of blocks in the housing areas show an awkward distribution of southeast and southwest orientations, as seen in the model.
The most relevant scheme concerning solar orientation seems to be the brilliant planning of Doxiadis for Islamabad. Doxiadis’s planning which seems to have certain influences from Le Corbusier, as in the water collecting basins, has a linear structure with an interesting idea of growth. I think we can easily call Islamabad a green city, where quite a variety of green areas with different scales are provided, on the edge of the green Margalla hills. May be more important than this, speed traffic is very successfully isolated from the city quarters with wide green stripes.
Plan for Islamabad, Doxiadis
Doxiadis’s well articulated blocks with a careful hierarchy of social spaces, give opportunities for a southeast-northwest exposed architecture in the great majority of the lots, avoiding the problem of monotony in the planned housing areas. Of course lot sizes and building regulations require more detailed examination.
Can we assert that Islamabad has the potential to be a model for a sustainable city? Let’s hope that this city with her brilliant linear plan can create a sustainable development somehow able to stay low rise and green in general.