Adaptable and Ecological
Synthesis defines Natural HVAC as a system in which airflow is generated using the sun, wind, and thermal buoyancy as opposed to electric fans. Supply towers containing intake dampers on all four sides extend above the building. The damper in the windward direction opens to “catch” the wind. The incoming air is then cooled by a cooling coil located near the apex of the tower. The cool, dense air then travels down the tower and enters an underfloor plenum from which it is distributed to occupied spaces. During winter months, the process reverses and cool air is taken in near the base of the tower and heated, causing it to rise and enter the plenum.
A solar chimney is used to draw air from occupied spaces. The natural stack effect is further enhanced using waste heat from the quad-generation process. The use of the waste heat allows the system to move an additional 1,000 to 2,000 CFM.
Keys to a successful implementation included: an ultra-low pressure drop air pathway, a well-insulated air pathway to avoid excessive heat gain in low velocity (200 FPM) system, and an extra commissioning allowance in the budget.
This system was vital in creating an 8% net positive site, and could not have been created without the hard work, dedication, and collaboration of the entire team.