Using Computational Fluid Dynamics to Evaluate High Tunnel Roof Vent Designs

Freestanding high tunnels are cost-effective, plastic film-covered growing structures that use very little to no modern environmental control technology. Natural ventilation is used temperature and humidity. Typically, openings created along the sides by manually rolling up a section of film cover. While common on greenhouses, roof vents not typically part tunnel designs in United States. This paper focuses during summer, when maximizing air exchange rate results low differential between inside outside temperatures. Computational fluid dynamics (CFD) simulations were evaluate effects several vent flow through temperature. The CFD models developed validated using data collected at Pennsylvania State University High Tunnel Research Education Facility (Rock Springs, PA, USA). Five simulated commercial software package was augmented with radiation crop architecture model. A root mean square error 0.87 °C found measured temperatures (n = 144). increase mass-based rates 20% 78%. However, they did lower more than 0.1 compared traditional design roll-up side only. Additional research needed whether other parameters weather conditions warrants vents, especially for humidity combination wind speed conditions.