Eco-friendly strategy for CO 2 enrichment performance in commercial greenhouses based on the CO 2 spatial distribution and photosynthesis

CO 2 enrichment is an essential environmental control technology due to its significantly enhancing effect on crop production capacity. Despite being a key energy consumer in protected agriculture (i.e. greenhouse systems), CO 2 enrichment remains at a low energy use efficiency level, highlighting the need for developing more energy-efficiency strategies for CO 2 enrichment. Therefore, this study employed the computational fluid dynamics (CFD) simulation method to replicate the CO 2 diffusion process resulting from CO 2 enrichment in three commercial strawberry greenhouses with varying geometric characteristics. Based on the CFD-simulated CO 2 concentration distributions, the leaf photosynthetic rate was calculated using a mathematical model group. The CO 2 enrichment efficiency was then analysed by calculating the ratio of increased photosynthesis across the cultivation area to the amount of energy (in CO 2 equivalent) used. The efficiency peaked when the average CO 2 concentration was approximately 500 μmol mol −1 , thereby providing guidance for determining the target concentration of CO 2 enrichment in production. Although this study is limited as the CFD simulation only considered a typical short-period CO 2 enrichment event, future research will provide a broader analysis by considering changes throughout the day.