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Using Computational Fluid Dynamics (CFD) Simulations to Achieve Optimal Air Distribution in Cannabis Facilities for Quality Growth of Plants
Kathryn Anne Lee, Amulya Surapaneni, Mehran Salehi, John Gregory Williams
Harris, United States of America
With increased legalization, cannabis cultivators are calling for improved indoor environmental conditions to produce high yields (Humphreys, 2017.). Cannabis growers prefer indoor grow facilities over outdoor for environmental control and security. Cannabis plants have varying sensitivities to temperature, air velocity, humidity, and lighting levels in different stages of their growth. It is important to maintain uniform environmental conditions in grow rooms and eliminate the possibility of damaging microclimates under plant canopies that may cause mold formation (“Vapor Pressure Deficit and HVAC System Design.” n.d.). A good air distribution design helps in maintaining uniform temperature, mixing of CO2, and removing the moisture around the leaves for the vital growth of cannabis plants. Even though there are some contradictory guidelines about good air distribution layout in cannabis grow rooms (Daugherty & Bonnville, 2020.), ("How to Ensure Proper Airflow at Your Indoor Cannabis Cultivation Facility", 2020.) there is no scientific study to back up these guidelines. These guidelines include the arrangement of inlets, outlets, supplemental fans, and grow lights in the grow room. This paper introduces a study to evaluate the aforementioned guidelines by testing variations in air distribution layouts for a flowering room in Las Vegas using CFD simulations. A base case air distribution layout is varied through 12 design iterations. The optimal air distribution layout to achieve desired indoor environmental conditions for a flowering room are proposed.
The findings of the study will benefit growers and designers considering that there is little to no previous relevant scientific research.
CFD- Trained ANN Model for Approximating Near-occupant Condition for Real-time Simulation
YUN Zhang, James Lo, Gabriel Grajewski
Drexel University, United States of America
Occupant thermal comfort is a critical parameter for efficient HVAC system design evaluation as well as the occupant-based dynamic control modeling. While the current design often assume the condition space is well-mixed, this assumption is insufficient to understand near-occupant conditions. The CFD simulation is a powerful tool to solve such problems by simulating the airflow field and associated parameters like relative humidity, air temperature, and air velocity, yet and CFD airflow simulation is time consuming which prevents its use in control systems and simulations in real-time. In this study, we present a real-time energy simulation combined with an real-time near-occupant condition model. This model is an Artificial Neural Network (ANN) model constructed and trained on CFD simulation results of an open office . The ANN model takes supply air, and wall surfaces temperature from the energy simulation as inputs and approximates conditions near occupants for assessment of occupant comfort. This work demonstrate the potential of using CFD results to train machine learning model and trained model’s efficacy in its performance in speed and accuracy.
21st Century CFD Prediction of Flow Regimes and Ventilation in 15th Century BC Tombs of the Valley of Kings
Cairo University, Egypt
Airflow characteristics in ventilated and air-conditioned spaces play an important role to attain comfort and hygiene conditions. This paper utilizes a 3D Computational Fluid Dynamics (CFD) model to assess the airflow characteristics in ventilated and air-conditioned archeological tombs of Egyptian Kings in the Valley of the Kings in Luxor, Egypt . It is found that the optimum airside design system can be attained, if the airflow is directed to pass all the enclosure areas before the extraction with careful selection of near wall velocities to avoid any wear or aberration of the tomb-wall paintings. The mode of evaluation should assess the airflow characteristics in any tomb passage according to its position in the enclosure and the thermal pattern and air quality. The airside design and internal obstacles are the focus of the present work. The free air supply and mechanically extracted ducted air play an important role in the main flow pattern and the creation of main recirculation zones. The internal obstacles can offend the airflow pattern by different ways, such as, by increasing the recirculation zones or by deflecting the main airflow pattern.