Numerical Analysis of Ventilation Efficiency of a Korean Venlo-Type Greenhouse with Continuous Roof Vents

Abstract

A Venlo-type greenhouse with a continuous roof vent (CR-Venlo greenhouse) was proposed by the Ministry of Agriculture, Food and Rural Affairs, South Korea (2019) for natural ventilation even during summers. It is ventilated through the buoyancy effect of the heated air using the high eave elevation. However, the CR-Venlo greenhouse was not distributed domestically, and its ventilation efficiency was not quantitatively evaluated. We aimed to analyze the natural ventilation efficiency of the greenhouse according to the eave height, using computational-fluid-dynamics. The simulation model was analyzed for hot summer conditions. The target greenhouse is ventilated only through the roof vent with all roof windows open; therefore, the air introduced through the roof window is easily exhausted. To evaluate the efficiency of ventilation, the external air entering through the roof window was calculated and evaluated. The amount of incoming air varied greatly with the location of the span and average temperature of the greenhouse; The temperature of the crop zone decreased lognormally with increasing height of the eave. Moreover, the ventilation efficiency of CR-Venlo greenhouse could be increased by improving the ventilation structure such as a shape, position or combination of roof window.

Advances in methodologies to assess wind actions in plastic-covered greenhouses

“…The various boundary parameters of the computational model (such as wind speed, outside and inside temperature, atmospheric pressure, air density, gravitational acceleration, viscosity coefficient, internal crop, and characteristics) have provided studies not only for structural effects, but also for ambiance in greenhouses. The CFD used to evaluate the efficiency of natural ventilation due to the height of Venlo-type multi-span greenhouses designed for tomato cultivation, contributed to the work to improve ventilation elements (Park et al, 2022).…”

Analysis of the Effect of Exhaust Configuration and Shape Parameters of Ventilation Windows on Microclimate in Round Arch Solar Greenhouse

“…Many scholars have analyzed the effects of natural ventilation on air flow and heat distribution in passive greenhouses located in tropical and subtropical countries by numerical simulation [28][29][30][31]. Park and Lee et al [32,33] used CFD method to simulate the natural ventilation of the greenhouse in the coastal area of South Korea, and evaluated the ventilation efficiency and ventilation volume. Santolini et al [34] used the CFD method to study the wind-driven ventilation in Italian greenhouses, focusing on the influence of the net on the airflow distribution in the greenhouse.…”