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

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