Browsing by Author "Na, Wook-Ho"

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    DYNAMIC NEURAL NETWORK MODELING OF THERMAL ENVIRONMENTS OF TWO ADJACENT SINGLE-SPAN GREENHOUSES WITH DIFFERENT THERMAL CURTAIN POSITIONS
    (2024) Akpenpuun, Timothy Denen; Ogunlowo, Qazeem Opeyemi; Na, Wook-Ho; Dutta, Prabhat; Rabiu, Anis; Adesanya, Misbaudeen Aderemi; Nariman, Mohammadreza; Zakir, Ezatullah; Kim, Hyeon-Tae; Lee, Hyun-Woo
    In order to produce marketable yield, scientific methodologies must be used to forecast the greenhouse microclimate, which is affected by the surrounding macroclimate and crop management techniques. The MATLAB tool NARX was used in this study to predict the strawberry yield, indoor air temperature, relative humidity, and vapor pressure deficit using input parameters such as indoor air temperature, relative humidity, solar radiation, indoor roof temperature, and indoor relative humidity. The data were normalized to improve the accuracy of the model, which was developed using the Levenberg–Marquardt backpropagation algorithm. The accuracy of the models was determined using various evaluation metrics, such as the coefficient of determination, mean square error, root mean square error, mean absolute deviation, and Nash–Sutcliffe efficiency coefficient. The results showed that the models had a high level of accuracy, with no significant difference between the experimental and predicted values. The VPD model was found to be the most important as it influences crop metabolic activities and its accuracy can be used as an indoor climate control parameter.
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    THERMAL PERFORMANCE AND ENERGY COST OF KOREAN MULTISPAN GREENHOUSE ENERGY-SAVING SCREENS
    (Energy, 2023) Rabiu, Anis; Adesanya, Misbaudeen Aderemi; Na, Wook-Ho; Ogunlowo, Qazeem Opeyemi; Akpenpuun, Timothy Denen; Kim, Hyeon Tae; Lee, Hyun-Woo
    Protected agricultural system such as a greenhouse cultivation is increasingly replacing traditional farming systems. Nonetheless, high energy demand in greenhouse farming requires innovative technologies through the use of climate screens to ensure sustainable production. Thus, this study developed a novel methodology for examining the energy retention capacity and economic effectiveness of greenhouse climate screen materials using their thermophysical, radiometric and aerodynamic properties in TRNSYS software. The TRNSYS model was developed to determine the energy consumption, which was validated using a multi-span Venlo-type experimental greenhouse (Yeoju, South Korea). Further analyses on energy saving capacity of different screens and the equivalent energy costs were performed. The results from this research showed that among the fifteen investigated screens, the ensemble screen (M3) saved 34.09 kWh.m􀀀 2 of annual energy, equivalent to 60 % of the heating energy demand, and energy cost of 4490.26 Korean won. m􀀀 2. Further, the results revealed that the climate screens with multi-layer, thermoreflective, low longwave transmissivity, impermeable and aluminized strips or surface characteristics and features have a considerable impact on reducing greenhouse energy use and desirable for high energy-saving. This research has demonstrated that the techniques and methods utilised can investigate all the types of covering and thermal screens used in greenhouse.