Prediction of the Energy Consumption for Indoor Strawberry Cultivation in a Tropical Climate

Abstract

This article addresses the lack of information for predicting the energy consumption of strawberry plantations inside plant factories located in tropical climate regions. This study aims to investigate the energy consumption of the cultivation of strawberries in the controlled environment room and to develop a TRNSYS computer model for the controlled environment room. Experiments were conducted in a 25 m3 controlled environment room. There are 180 strawberry trees inside the room. Light Emitting Diode (LED) grow light substitutes for natural sunlight. An air conditioner was used to regulate the indoor air condition. A computer model was developed using TRNSYS (TRaNsientSYStem simulation tool) and was validated using the collected data. There are three main components of the room heat load: transmission, lighting, and evapotranspiration. The lighting heat load shares more than 96% of the total heat load — the evapotranspiration load increases when the LED turns on. However, the lighting consumes only about 36% of total electricity consumption, while the air conditioner consumes 64%. Most of the electricity is used during the runner stage. Electricity consumption can be saved by 40% if the runners are grown outside the plant factory. Therefore, the high heat load is a feature in the plant factory. In this study, the lighting heat load is the most significant parameter. The strawberry light intensity requirement is the high lighting heat load. Consequently, the electricity for the air conditioner becomes high since the air conditioner removes the generated heat from the high light intensity. Therefore, the air conditioner electricity consumption is enormous in this study. Moreover, the required lighting intensity, photoperiod, and low air temperature factors affect electricity consumption. Therefore, the results from this study could provide strategies for energy cost reduction and plantation management for plant factories cultivation.