The Invisco Tornado hybrid rooftop ventilator is the highest performance rooftop in the world. Kurt Shafer here to tell you how I know it is the best. I learned about a company, CSR Edmonds, in Australia, that sells a long line of hybrid rooftops they call ECOPOWER. These rooftops are motorized versions of their other very popular gravity rooftops, their line they call Hurricanes. The value of their design cannot be overstated. They approached the challenge of rain drops with an entirely different view than anyone anywhere else in the world.
Their engineers used vertical turbine blades under a domed top to deflect rain drops. The result is a cleaner path for air than that offered by any other rain hat. The result is shown graphically in this efficiency comparison between Invisco and 2 other American sources, Greenheck and LorenCook – this performance data shows clearly that it is easier to push air up using this rain hat.
Here is a picture of the Australian ECOPOWER fan with a small motor under the turbine next to the Invisco Tornado fan with a large motor and blade to move as much air as possible. The center fan is not my invention. The right one is.
AEI engineers used the Australian ECOPOWER EP900 (900= 900 mm = 36 inches diameter throat) on the roof of the 4 story Molecular Engineering building at the University of Washington in Seattle. Their purpose was to use the very good gravity air flow early in the day saving powered air flow for later as the internal temperature built up faster. They put automatic window openers on most of the windows on the ground floor of the 4 story building so they opened when the building became occupied in the morning to allow cool morning air to come in using the gravity air flow. This eliminated the need for air conditioning. As the interior warmed up under body heat the need for more cool air exceeded the capacity of the gravity air flow so the motors in the hybrid rooftops were energized to increase the flow to offset the building temperature. The result of their work was the achievement of meeting LEED5 air qulity..
LEED v5 is the next-generation [Leadership in Energy and Environmental Design] rating system from the USGBC, designed as a comprehensive framework to guide buildings toward a decarbonized, resilient, and equitable future. It focuses on measurable, long-term performance across three key impact areas: decarbonization, quality of life, and ecological restoration
Why the Tornado is perfect for this application – infinitely variable speed
Most buildings are in locations with far hotter average temperatures so the ECOPOWER design might not perform as well as the more powerful Tornado. The Tornado’s air flow power is variable from zero to full speed and the Electronically Commutated Motor draws almost no power at low speed and increases the power nearly perfectly linearly as the speed goes up. This new performance feature was not incorporated in the early days of the ECOPOWER.
The result is a line of rooftops ranging in size from 10 inches diameter throat up to 36 inches that, when powered, pull from a few hundred CFM up to 14,000. And the air flow at higher static pressures is impressive 11,578 CFM at 0.2 static pressure.