Computational Fluid Dynamics-based Simulation and Analysis of Air Conditioning System Application in Watercress Mini Plant Factory

Abstract The projected population of Indonesia to reach of around 320 million people in 2045 is worried to threaten the growth of various plants. The threat occurs due to various human activities that result in reduced land for growing plants and climate change. Plants are needed by humans as a source of food, medicine, and other valuable products. Plant Factory (PF) is a place for indoor plant production with climatic conditions that can be adjusted according to needs and is used as an effort to increase plant production on limited land. The Mini Plant Factory (MPF) is a small-scale of PF. This study concerns to simulate the MPF model in order to understand better the distribution of air temperature and velocity in it. Computational Fluid Dynamics (CFD)-based simulations were carried out in the bright period (plants carry out photosynthesis) and dark period (plants carry out transpiration). Transient simulations conducted to determine the duration of the AC compressor turns on and off in a day operation. The duration is used to calculate the operating costs of the MPF. The investment costs and income are also calculated to estimate the payback period of MPF. The air temperature around the planting rack is kept close to 21°C in the bright period and 19°C in the dark period. Within 24 hours, the AC compressor is on for 9.2 hours and off for 14.8 hours. The investment cost incurred to make MPF on an existing building is IDR 22,961,471.00. MPF can generate income of IDR 11,673,851.00 annually. The payback period of MPF project in this study was around two years.