Evaluation of Annual Cultivation Schedules via Energy Management Indices in Solar-light Plant Factories

Abstract

　To improve the annual profitability of solar-light plant factories that utilize heat pumps for year-round cultivation, it is effective to analyze and research the optimization of the annual cultivation schedule by utilizing cooling during summer nights. In this study, we developed a method to quantify and evaluate annual energy conservation, the compatibility between energy conservation and productivity improvement, and profitability when the start of cultivation is changed arbitrarily, utilizing energy management indices. Compared with the current cropping system, over-summer tomato cultivation started in December or February, improved the annual energy efficiency, increased the annual saleable yield, and increased the annual profit by 27 % when started in December.