Thermal analysis and climate control of experimental two level hydroponic growth cell

Abstract

The research focuses on providing optimal conditions for growth, energy efficiency, and sustainability, controlled and autonomous environment. A two-level hydroponic growth cell is proposed as an experimental facility to design of in-door multilayer plant production systems. The goal of the system is to serve as a practical and useful alternative to traditional field agriculture. The growth cell has of 1 m2 each level area and composites two rows of hydroponic growth elements. The cell is designed to carry out multiple functions essential to sustain plant growth that includes: Water circulation, nutrients delivery, environment sensing, ventilation, and artificial selective lighting. The series of repeated growth cycles have been successfully performed and compared against a conventional greenhouse facility using lettuce as a model crop. The factors such as inside temperature and humidity, leaf temperature, illumination under three different lighting types: White light, red-blue light, sunlight were monitored and maintained by a developed control system. Light distribution (photosynthetic active radiation) and yield (leaf size and fresh weight) were assessed. It is shown that sunlight is the more profitable type of lighting for lettuce crops even under warm outside environmental conditions. These results illustrate that the use of transparent covering materials offer great potential for energy save cultivation and should be considered for a plant-factory design.