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Interaction between Building Envelope Pressure Loading and Indoor Air Distribution
Start Date 05/01/2007
End Date 04/30/2008
Primary Partner: Syracuse University
Primary Contact: Dang, Thong - Director/Professor
Other Project Contacts: Khalifa, H. Ezzat - Co-Principal Investigator
Project Type: CARTI II
Technical Description:
Today's green buildings are designed to interact symbiotically with the outdoor environment. These high performance buildings utilize sustainable technologies such as renewable energy, energy-efficient designs, and natural ventilation. Natural ventilation is sensitive to outside temperature and wind, as is the distribution of contaminants within the building and occupant exposure to them. This proposal concerns the dynamic interactions of natural ventilation with indoor air quality. Several strategies of manipulating the aerodynamic loading around the building envelope (or local static pressure difference between outdoor and indoor) are proposed to control the local air infiltration, the redistribution of indoor contaminants, and the prevention of outdoor contaminants infiltration into the indoors (e.g., into a building near a freeway at rush hour). The manipulation of the aerodynamic loading can be achieved via flow blowing/suction in the presence of a wind or other devices depending on the geometry of the building (e.g., cylinder shape versus block shape). The source of the blown/sucked air around the building envelope is the result of air intake/exhaust from the building, along with wind energy harvesting (or mechanical ventilation in the absence of wind) for HVAC and air filtering equipments.
Expected Outcomes:
The proposed system is designed to provide a comfortable and healthy indoor environment while minimizing energy consumption.
Accomplishments:
Using 2D CFD simulations, it is shown that the air distribution inside a naturally-ventilated building can be modified drastically by
(1) deploying one or two flow-resistance devices at different positions along the perimeter of the building, and
(2) adjusting the magnitude of the flow resistance on these devices. For example, at a fixed wind direction, it is possible to reverse the pressure loading around the building, hence inverting the direction of cross ventilation.
To evaluate the effectiveness of the proposed concept in controlling IEQ, the network flow software CONTAM was used to simulate the indoor environment inside an elliptical-shaped building with a very simple floor plan consisting of 8 zones (or rooms) connected by a common walkway.
The results of running the network flow software, using the CFD envelope pressure loading results as input, show that except for the rooms near the stagnation-point region, the distribution of air intake or exhaust in each zone can be controlled at will.
Finally, 3D CFD simulations show that it is possible to manipulate the pressure distribution around the buildings by installing as few as one flow-resistance device every 5-10 floors. We are also working on a concept at the multidisciplinary level by addressing its practical implementation.
Benefits:
Employing methods and technologies that utilize natural airflows and building aerodynamics will provide healthy and inexpensive ventilation to public spaces and work areas.
For more information: http://www.ecs.syr.edu/Faculty/dang/main.htm
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