Evaluation of plant canopy microclimates with realistic plants in plant factories with artificial light using a computational fluid dynamics model

Airflow parameters play a vital role in regulating the microclimate of the plant canopy and significantly affect plant development and growth in plant factories with artificial light (PFALs). A computational fluid dynamics (CFD) model with a realistic soybean canopy was developed to predict the distribution of radiation (W m−2), leaf temperature (°C), air velocity (m s−1), air temperature (°C), and relative humidity (%) within a plant canopy. The accuracy of the CFD model was confirmed by comparing mean absolute percentage errors of these variables which were 9.9 %, 1.4 %, 11.4 %, 0.8 %, and 1.8 %, respectively. The validated CFD model was used to simulate the lamp temperature and microclimate distribution of the soybean canopy under different inflow parameter levels on a cultivation shelf. The results revealed that the microclimate was primarily influenced by lamp radiation rather than convective heat when the inflow velocity was below 0.57 m s−1. Inflow velocity, air temperature, and relative humidity exerted more significant effects on air velocity, air temperature, and relative humidity, respectively, than the other variables in the plant canopy. The increase of inflow velocity significantly improved the uniformity of air velocity, temperature, and relative humidity in the plant canopy. However, note that this study investigated the lamp temperature and microclimate distribution in plant canopies under different airflow parameters using the CFD model without coupling plant transpiration to the surrounding climate. This provides valuable insights into the control of the plant canopy microclimate in general and more particularly on the shelves of PFALs.