Analysis of Natural Ventilation Rates of Venlo-type Greenhouse Built on Reclaimed Lands using CFD

Abstract

Recently, the Korean government announced a new development plan for a large-scale greenhouse complex in reclaimed lands. Wind environments of reclaimed land are entirely different from those of inland. Many standard books for ventilation design didn't include qualitative standard for natural ventilation. In this study, natural ventilation rates were analyzed to suggest standard for ventilation design of venlo type greenhouse built on reclaimed land. CFD (Computational Fluid Dynamics) simulation models were designed according to the number of spans, wind conditions and vent openings. The wind profile at a reclaimed land was designed using ESDU (Engineering Sciences Data Unit) code. Using the designed CFD simulation model, ventilation rates were computed using mass flow rate and tracer gas decay method. Additionally computed natural ventilation rates were evaluated by comparing with ventilation requirements. As a result of this study, ventilation rates were decreased with increasing of the number of spans. Ventilation rates were linearly increased with increasing of wind speed. When the wind speed was 1.0 m·s -1 , only side vent was open and wind direction was 45°, homogeneity of ventilation rate at 0∼1 m height is the worst. Finally, chart for computing natural ventilation rate was suggested. The chart was expected to be used for establishing standard of ventilation design.

Research on the Microclimate of Protected Agriculture Structures Using Numerical Simulation Tools: A Technical and Bibliometric Analysis as a Contribution to the Sustainability of Under-Cover Cropping in Tropical and Subtropical Countries

“…On the other hand, recent studies have recommended the octagonal-type greenhouse because they have better ventilation rates and better temperature distribution compared to greenhouses equipped with side and roof ventilation [137]. Likewise, with respect to geometry, it is increasingly common to find studies that recommend increasing the height of structures in order to improve the efficiency of the natural ventilation phenomenon [148].…”

“…Simplified method 62 [19,32,[37][38][39]46,49,76,78,83,91,95,99,100,106,[108][109][110][111][113][114][115][116][120][121][122][123]126,129,131,133,136,[141][142][143][144][145][146][147][148][149]151,[153][154][155][156][159][160][161][163][164]…”

Ventilation Operating Standard for Improving Internal Environment in Pig House Grafting Working Conditions Using CFD

“…The CFD model was designed with a combination of regular tetrahedrons, triangularshaped tetrahedrons, grids, regular hexahedrons, and square-shaped hex-dominant grids to represent the complex shapes found in the pigpen following the previous validated modeling approaches [20][21][22]. Dense meshes were used for aerodynamically important areas of the pigpen, such as inlets, outlets, or regions near complex structures, to enhance model accuracy [39][40][41][42][43][44]. The calculation area was subdivided into smaller sections for analyzing the ventilation efficiency and thermal conditions.…”

CFD Model Verification and Aerodynamic Analysis in Large-Scaled Venlo Greenhouse for Tomato Cultivation

“…To increase the stability of the flow in the upper part of the greenhouse in the model, it is necessary to secure sufficient height. At the same time, by setting the ceiling as symmetrical, it was more flexible and able to maintain linearity than setting it as a wall [6,8]. The Venlo-type greenhouse has a floor area of 2 ha, and tomatoes were assumed as a porous media and reflected in the design (Figure 4).…”

“…Under the unfavorable climate conditions, it is necessary to establish large-scale protected agricultural facilities to meet the increasing population pressure on food production systems. The Korean government recently initiated a project to develop large-scale greenhouse complexes on reclaimed land aimed at cultivating and exporting high-quality horticultural products year-round [6]. Additionally, research has been conducted on atmospheric conditions and greenhouse construction on Korean reclaimed lands [7,8].…”