3RD INTERNATIONAL CONGRESS ON TECHNOLOGY - ENGINEERING & SCIENCE - Kuala Lumpur - Malaysia (2017-02-09)

Study On Light Source Energy For Numerical Simulation In Plant Factory

Currently, awareness is increasing of the destabilizing effects of abnormal weather on crop production, the decrease in the number of agricultural businesses, and food safety. Therefore, the focus is on plant factories that allow for stable crop production and efficient and safe vegetable production. Plants produced artificially in factories are more expensive than those produced in open air. To lower production costs, the cultivation environment needs to be appropriately controlled, and the growth rate of plants needs to be improved. The following environmental factors are associated with growth: air temperature, humidity, wind speed, CO2 concentration, light strength, and nutrients components. Productivity decreases due to inconsistency in cultivation quality caused by the effect of inconsistent environmental factors in these factories. To optimize the cultivation environment in these factories, it is important to first evaluate the air temperature, humidity, wind speed and CO2 concentration distribution with a numerical simulation in order to optimize air-conditioning. In fully artificial light type plant factory that uses a lighting device in place of sunlight, there is little cooling load caused by ventilation or wall heat transmission, and as 80% or more of the cooling load comes from heat generated by the lighting device. Therefore, the lighting device has a significant effect on the air conditioning load. Further, it is considered that the photosynthetic rate is also effected by the lighting within the cultivation room. In this paper, in order to comprehend the effect of the latest lighting device on air conditioning load, lighting experiments using Hf fluorescent lamps and LED are performed, and it is investigated the distribution rate to the light in electrical energy from each lighting device. In order to study the effect of lighting devices on air conditioning load in plant factories, lighting experiments were performed, and by incorporating those results into the air conditioning simulation with plant activity, the following result was obtained. (1) From the lighting experiment, the distribution rate ω of electrical energy to light was 0.52 for Hf and 0.56 for LED, and a certain difference was seen. (2) By removing ballasts and internal circuits, there was a reduction in lighting load of 6% for Hf and 15% for LED. So by placing ballasts or internal circuits outside the cultivation room, the air conditioning load can be reduced.
Atsumasa Yoshida, Koji Moriuchi, Yasushi Ueda, Shinichi Kinoshita