A few years ago representatives from the Palestinian Department of Education made a tour in Belgium, in search for new school concepts. We had the opportunity to guide them through our passive school in Bocholt, which is conceived as a multi-purpose school. After school hours, part of the playing ground and school buildings can be used by the community.
In 2014 the Palestinian Ministry of Education and Higher Education (MEHE) invited us for an enclosed, international architecture competition for a new high school for girls in Bakhri, Hebron. The project will be achieved with the expertise and financial support of the Belgian Development Agency (BTC). lava architecten formed a joint venture with a local partner, ARAB Engineers. The competition design was made by lava, but the further development will be done completely by ARAB Engineers, with lava acting as an extern consultant.
The terms of reference specified three ambitions: the school had to be child friendly, eco-sustainable and incorporate a sports hall and an environmental lab, which could operate independently as well. We tried to answer the particular conditions of climate, topography and politics with local solutions and customs, where the human capital can thrive.
The site is characterized by retaining walls made of stone, creating terraces, following the natural height lines. We add some new retaining walls, and preserve the most flat area as a common sports and playground. The classrooms are divided over the three terraces, grouped according to age, from young to older. Each terrace has a green border. This creates natural buffers between the different age groups, ensures the presence of greenery on site, and allows delayed water infiltration. The green borders also create a safety zone for the height difference between the terraces.
A new connection for pedestrians is created between the existing road and the new road. This new axis is not only a connecting route between the two public roads, but also accommodates the internal circulation of the school itself. On top of this connection, 4 ‘towers’ are placed with common functions for pupils of all ages, like the library, the laboratory and environmental lab. The also define the internal and external circulation. The internal circulation administers the classrooms. The external circulation on top is a more public route which administers functions such as administration, the environmental lab and the sports hall.
The towers are connected by an outdoor and indoor staircase, one on top of the other. This enables to access all school functions both from the outside and from the inside. Several smaller outdoor staircases connect the different terraces, creating informal passageways for the children. This way, the age groups can be kept apart or connected when needed.
The complex is accessible through 2 gates: one at the top (sports hall) and one at the bottom. The car parking and bicycle parking are located at the upper entrance. The sports hall, the outside sports grounds and the environmental lab are accessible when the school is closed.
Local climate is very hot in summer and very cold during winter time. Furthermore, schools have no forced heating nor cooling system in Palestine. We had to search for clever solutions. The extended arched hallways are fitted with roll down sunscreens which have a double function. During hot days the screens provide shade for the classrooms. At night or after school hours, the shades can be pulled down to lock up the school building.
Placing the classrooms underground is an effective way to create high thermal inertia. In addition to this, all walls are insulated with 20cm of insulation and all windows are double glazed. During the warmer months these measures help keep the air cool. During the coldest months they insulate the building from the cold.
Persian wind catchers are used to provide natural ventilation in the hallways and classrooms on windy days. The concept of the Persian wind catcher can be extended with two sustainable measures: we can add the principle of a solar chimney and even a passive down-draft cooltower. A solar chimney had got the advantage that on hot windless days it can provide ventilation where otherwise there would be none with only a Persian wind catcher.
The difference in height between the lowest part and the top part of our 'environmental lab tower' is 21m. These two parts are connected by the internal staircase, which is completely open, thus creating s sort of diagonal 'chimney'.
Natural ventilation can be created by providing vents in the upper level of a building to allow warm air to rise by convection and escape to the outside. At the same time cooler air can be drawn in through vents at the lower level.
Trees may be planted on that side of the building to provide shade for cooler outside air. To further maximize the cooling effect, the incoming air is led through the hallways next to the classrooms, which are digged into the rocky slope. The use of the solar chimney benefits natural ventilation and passive cooling strategies, thus reducing energy use, CO2-emissions and pollution in general.
We can even go one step further. Underneath the sports hall, a vast water tank is provided. By spraying the water over the incoming air, a downdraft of cool air is created, which will cool down the inside temperature, which is a form of adiabatic cooling.