Toward Sustainable Agriculture: The Design of Environmentally Friendly, Economical, and Modular Vertical Farming Systems

The increasing population and continuous urbanization make food security a key consideration in sustainable development. Efficient farming strategies with low environmental footprints are thus increasingly required to meet food demands. This study presents a design for environmentally friendly, economical, and modular vertical farming systems, in which vegetables are cultivated in a carbon dioxide (CO₂)-enriched atmosphere enabled by direct air capture (DAC) and subjected to artificial light exposure. We established a vertical farming setup and conducted experiments to identify productive cultivation strategies by regulating lighting, CO₂ concentration, biochar application, and plant species. Additionally, a self-developed DAC rotary adsorber was utilized to achieve stable and efficient CO₂ enrichment. Compared with the control group, the fresh weight of the vegetables in the experimental groups increased by up to 57.5%. Furthermore, we performed a comprehensive evaluation of the design and demonstrated that integrating photovoltaic-thermal (PVT) and DAC units increased the system’s net present value (NPV) by 157% compared with a conventional design without these units. Importantly, we found it possible to maintain the low carbon footprint of the system (0.468 kg-CO2 equivalent (CO₂eq)∙kg⁻¹-vegetable) in the production process. Parametric studies and an application analysis on a global scale reveal the wide adaptability of this strategy to diverse conditions. These findings, together with the modular characteristics of vertical farming systems, highlight the promising potential of this design to increase food security and foster sustainable agriculture.