For more information: http://nvactropicalgreenhouse.weebly.com Natural Ventilation Augmented Cooling Greenhouse. An alternative approach to cooling and ventilation in hot climate greenhouses. Patented in USA, Canada and Australia. Designed and developed by Lucas McCartney, a PhD candidate and Dr. Mark Lefsrud, an Associate Professor, both at McGill University, Macdonald Campus, Department of Bioresource Engineering.