Solar light distribution system for multilayer cultivation in a smart greenhouse

Abstract

There exists a strong need for developing an artificial cultivation environment for sustainable and low-initial investment solution in order to solve economic problem and to maximize energy efficiency of the existing plant factories. This research is to replace existing high density plant factory's artificial light source with natural light. This is especially necessary to reduce the initial investment of the light source installation as well as operation cost due to the power supply for increasing the production of crops. Maximizing the use of solar light also improves the quality of the plants grown just like those exposed to the natural environment. In order to provide qualitatively superior solar light to the multilayer plant facilities, collecting maximum, stable and direct sunlight without loss by tracing solar path and properly spreading it through careful control of the inflow during daytime is indispensable. We design and suggest a series of light shelf for a plant facility which induces the excessive direct sunlight to the deeper part of the facility while reducing the amount of upper side luminosity utilizing optical transfer effect. And it tracks the movement of the sun based on daily and annual solar path changes for maximizing the sunlight entering into the facility and supplies the natural light in the direction of a diffuse panel. In this investigation, through introducing a new generation roof-top mounted light shelf equipment, we developed an innovative way of effectively allocating sunlight inside even to the typically shaded zone of a multilayer plant facility, which is promising for maximization of energy saving and plant cultivation efficiency. To prove the effectiveness of our system's sunlight collection and distribution capability, the daylight environment of Daejeon is investigated and applied to our verification simulations.