PLEA2006 - The 23rd Conference on Passive and Low Energy Architecture, Geneva, Switzerland, 6-8 September 2006
6. FINAL COMMENTS
Figure 7 : Ventilated sky lights.
Figure 8 : Sky light operation
Figure 9: Main atrium space finished by June
Sustainable tropical architecture leads with many factors, which encourages strategic but simple solutions. In this case the budget allowed to the project has a direct and mandatory relation to the commercial success. In many cases the commercial building promoter decides to use air conditioning systems, even if natural cooling systems are suitable as an initial and operative cost structure. This is a result of a cultural expectancy. In the Villavicencio commercial mall (see fig 10), the shop owners and the promoter tacked the decision to use natural cooling systems as a result of economical reasons and low expectancies regarding the customers profile. Many technical specifications require to be reviewed in order to make possible and adequate cost structures. As an example, aluminium sky light blinds (imported) were changed to steel home made blinds. The roof insulation was defined initially as expanded polyethylene. The local available roof using mineral wool was finally decided even if the thermal conductivity is less increased. Finally, it is important to comment that high tech cooling strategies, in many times are not the best alternative under the developing countries context. Consequently, naturally cooling techniques could be effective and economically achieved if some criterion are regarded:
The use of a combined horizontal/vertical air flow pattern is strongly encouraged.
If a light weight building (suitable for hot humid climates) is not possible, and a massive building is designed. Roofs and walls must be carefully designed as double ventilated envelope. This promotes radiant heat release and lower insulation costs.
Complexity in the general plan, as a result of architectural needs, could be managed if the space´s thermal balance is divided separately in “typical thermal areas”. This because, heat transfer patterns changes depending on the level floor, volume, area or occupancy pattern (corridor, café terrace, service areas etc).
Shading devices are encouraged using simple solutions as Venetian blinds, or cantilevered sun grids. Is not recommended for sun control the use of complex volumes. In this case facades and openings could be placed at the same plane, in order to allow incoming breezes to come into the building. This is illustrated by the figure 11 and figure 12.