WADI SABBARA
E N V I R O N M E N T A L S T R A T E G I E S H A N D B O O K
KarmBuild Author: Hassan Elghayesh Š 2017 all rights reserved Layout: Hassan Elghayesh Drawings: Hassan Elghayesh Fonts: Swis721 BLK BT Century Gothic
STRATEGY
The idea is to rely on passive strategies to help improve the experience of staying in Wadi Sabbara. The main problem as observed from the research would be in summer; as temperatures rise, overheating would be the main problem. Early morning glare would pose another problem. Taking into consideration that direct seaviews are to the East means that there will have to be a compromise between decreasing heat gains “closing up” and offering glazed surfaces to the view “opening up”. Strong winds can be used to relieve the building of it’s high temperature gained from sun radiation. Wind draft + evaporative cooling effect can prove a good strategy for dealing with the environment of Wadi Sabbara. These strategies cab help define a strong architectural caracther for the development. Each strategy is not meant to work on its own. Hybrid strategies can emerge and be elaborated upon.
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88° Fig. 1 graph_monthly, average temperatures in wadi sabbara
41° temperature in °C
month
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Fig. 2 isometric_study of sun movement during summer and winter with overlay of wind movement
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115°
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65°
245° NE - prevailing winter winds
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N 0°
295°
N - prevailing summer winds www.suncalc.net www.esrl.noaa.gov/gmd/grad/solcalc/azel www.windfinder.com/windstatistics/marsa_alam
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Fig. 3 isometric_stack effect through stairwell
WSE.001
Fig. 4 section_stack effect through rooms and stairwell.
Stack effect can be a very valid strategy to enhance air circulation through the building. The pressure difference between outside and inside creates a difference in pressures that will cause air to circulate through the building. There must be a direct vertical connection in order for the air to circulate uninterrupted. The connection can be created with the sole purpose of air circulation. It can also be attached to an already existing uninterrupted vertical element within the building “the stairwell�. Rooms adjacent to the stairwell must have openings opening to it. This strategy cannot work within an air tight building and must be coupled with other strategies in order to reach full potential.
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wall section_60 cm solid coral stone
WSE.002
15 cm Coral Stone
60 cm Coral Stone
Fig. 5
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15 cm Coral Stone
10 cm Red Brick
10 cm Air Gap
10 cm Red Brick
60 cm Coral Stone
wall section_60 cm coral stone with air gap
15 cm Coral Stone
Fig. 6
Thermal heat capacity is a very important aspect of deciding on building envelope. Coral stone is the material most available on site, The downside is that stone has a relatively high thermal conductivity. To work against this downside, we can adopt two different strategies. First (fig. 5) would be increasing the width of the wall, this is already needed structurally in a stone building. The wall will, thus, possess a very high thermal capacity. There is a possibility for the building to collect heat in the morning and dispatch into the building at night or vice versa. Another approach (fig. 6) could be to create an air gap in between two stone walls in order to increase the overall thermal resistance of the wall per surface area. This can be coupled with other ventilation techniques to insure the air does not get trapped in a loop of convection that would actually increase heat gain rather than decrease it. Further simulations should clarify which solution should be used on which wall. 0.60 0.60
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Fig. 7
WSE.003
plan_air circulation through building
Through cross ventilation, favorable winds can be encouraged to circulate through the house. A constant air stream can be ensured if openings, whether windows or doors, are aligned along the wind direction. The focus should not only be on exterior walls but also on interior wall openings, openings can be added on top of doors or doors can have vents to keep the air flow uninterrupted. Notice that the cross ventilation can be further enhanced by having smaller openings for air to enter and larger openings for air to escape. On our site this means; North East facades should have small openings while South West should have larger openings to strengthen the air flow.
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WSE.004
Fig. 8 isometric_wind catchers can act as strong architectural elements
Fig. 9 section_air flow through windcatcher
Wind catchers have been employed as an environmental strategy in hot temperate zones for a long time. Whether in an urban or rural condition the strategy has shown great results in improving air draft through the building, lowering the temperature to reach the comfort zone for the user. Wind catchers usually work hand in hand with other air circulation strategies such as WSE.001, WSE.003, WSE.005 and WSE.011. The wind tower itself is an architectural element that has strong qualities and can be used to give a strong character for the development. Downsides are; the strategy would need a lot of interaction on the user’s side in order to stay relevant, also, the building would lose air tightness needed to operate mechanical air conditioning or ventilation.
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WSE.005
Fig. 10 section_stack effect through double height
Double height spaces can be integrated within a building to create a stack effect similar to the strategy in WSE.001. The double height spaces fall high within the hierarchy of spaces and can be used for the main living space within the building. The space will have a much cooler temperature as hot air rises to the top part of the space. A lower marble floor can enhance the cooling effect of the space. When openings from adjacent rooms open up to the double height space; the space can act as a hot air escape for the whole house.
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WSE.006a
Fig. 11 plan_air flow through courtyard building
Courtyard buildings as a typology can be very helpful in lowering the temperature all through the house. They can also enhance the social quality of the house if it doubles as a communal space for outdoor activities and gathrings. With a fountain added, The humidity and air draft will lower temperatures significantly. The main problem would be the increased surface area as opposed to a closed building as elaboreted upon in WSE.010. A bigger surface area exposed to the outside means more heat gain for the building. Yet, the cooling effect of the courtyard can counter the problems arising from bigger external surface areas.
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WSE.006b
Another option would be to create a fully shaded courtyard, a semi open wooded pergola is a compromise between total openness that jeaopardizes the courtyard’s function as a cooling generator. Yet, this affects the concept of an open sky courtyard with its special spatial experience. The shaded pergola acts as an additive element as opposed to an element that feels more integrated. The change of material can be interesting and will add another layer of complexity to the building technique.
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WSE.007
Fig. 12 isometric_evaporation tower as an architectural element
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Evaporation towers are a strategy that needs much interaction from the user. Much like WSE.004, The towers help catch air from the outside into the building. A dampening mechanism makes air humid as it falls to cool the spaces. The water tanks can be controlled with simply controlled with floating valves. Yet, it is expected the system might need a lot of maintenance. The air draft + humidity are the best combination for dealing with overheating that will occur in the summer months, taking into consideration that summer is the month with the strongest winds. Towers will give a very distinctive architectural character to the buildings. A play on the rhythm of the towers can be reached between adjacent buildings.
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section_air flow through courtyard building
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WSE.008 Fig. 14
Fig. 15
plan+elevation_overhead and side shading protects glazed surfaces fromB direct sunglight
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section detail_overhead and side shading elements protect glazed surfaces from direct sunglight
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B B-B
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A-A
B-B
To decrease direct radiation on glazed surfaces, the windows are flushed with the interior surface of the walls. Thus, it will be set back by 60 cm. Sun breakers will extrude from the building around glazed openings in order to protect from sunlight at different times in the day while opening up to the view. This solution can be used to overcome the problem described earlier at the eastern facades that have sea view but may suffer from early morning glare. The shading elements will be plastered in the same material as the walls and become a part of the building rather than a foreign element, a defining element of the architecture.
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WSE.009a Fig. 16 isometric_vertical shading elements option (a)
Another strategy to deal with the problem of sea view on the eastern facade would require using large vertical shading elements. The large glazed surface us a must to offer maximum view, the eastern sun is low and angled in the early morning. By using slender vertical elements an acceptable compromise can be reached between view and too much direct sunlight. The strategy can be a defining architectural element adding rhythm to the facade from the outside and a unique natural light experience for the inside. Downside for this proposal would be the louvers extending from outside to inside can act as heat bridges.
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Fig. 17 plan_vertical louvres break the sun while offering a wide view to the outside
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WSE.009b Fig. 18 isometric_vertical shading elements option (b), creates a buffer zone
Fig. 19 plan_a buffer corridor is created between vertical elements and glazed opening.
WSE.09b is a play on the earlier model for vertical shading elements. In this case, the vertical elements are rotated and given a 2 meter distance from the glazed wall. The distance allows for views to the sea that are rhythmic, in this case maximum view is sacrificed in order to offer better protection from the sun. An outdoor space that is protected from the sun can also be created. This option can be combined with horizontal shading.
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WSE.010
Fig. 20 diagram_building proportions, 100 m2 area vs. perimeter
This strategy is one of the first decisions to be made, along with orientation. The ratio of surface area exposed to the outside can be decisive in solving environmental issues. A circle will offer the most enclosed floor area to outside exposure, thus, lowering the amount of heat gained from exterior walls. This can be good in the case of trying to solve the building as an air tight space controlled with air conditioning. The more rectangular the building gets the more heat it will gain from the outside. Courtyards will significantly increase the surface area exposed to the outside. Yet, as mentioned in WSE.006, a courtyard with good ventilation would not be a problem. The decision is to be made between less heat gain and more heat gain but with a wind cooling effect.
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WSE.011
Fig. 20 section_cross ventilation with water surface
For the high end residential units that contain pools. The pools must be used in conjungtion with WSE.003’s strategy of cross ventilation to lower the temperature within the unit. Humidity and air circulation are the strongest strategy aginast high temperatures. A pool within the unit plot has very strong potential in offering a unique spatial experience that is luxurious but at the same time environmentally relevant.
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WSE.012a
Fig. 21 elevation_horizontal louvres on southern facade
Fig. 20 section_cross ventilation with water surface
Dealing with the southern facade will differ from the eastern facade; in the southern facade the sun is at a very high angle at summer, the 60 cm setback within the wall is sufficient to deal with the direct sunlight. The biggest problem on the south would be the sun radiation hitting the walls. This is solved through WSE.002 through the wall sections. The louvres on the southern facade are horizontal, slightly at an angle equal to 40 degrees. This way summer sun is kept from directly falling on the glass while in winter it can penetrate it at a low angle bringing warmth to the inside.
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WSE.012b
Dealing with the southern facade will differ from the eastern facade; in the southern facade the sun is at a very high angle at summer, the 60 cm setback within the wall is sufficient to deal with the direct sunlight. The biggest problem on the south would be the sun radiation hitting the walls. Thus, planting on the southern facade can be a good opportunity to “beautify� the unit, a contrast of built and planted a moment of tension. The strategy could be also used to hide plumbing and HVAC ducts. The most important function would be to offer relief from direct sunlight on the walls.
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WSE.013
Fig. 21 section_building next to the contour
This strategy builds upon the observations in WSE.010 regarding surface areas exposed to the outside. It also makes use of the site topography. The strategy is mainly for the units adjacent to the steep contours of the valley. By building the unit right next to the contour, we can help protect it from the sunlight, Also, The wall will not be subject to influence by outside temperatures but rather by the relatively cold stone on the sides of the contours. If an architectural resolution can be reached on leaving the stone bare, it can offer a unique spatial experience, that will define the units as special.
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