CO2 enrichment.

Feeding photosynthesis its raw material

Photosynthesis runs on carbon dioxide, and a healthy, actively growing crop consumes it faster than the air inside a closed greenhouse can replenish. On a bright morning with the vents shut to retain heat, CO₂ levels inside can fall below the outdoor atmospheric concentration, and at that point the light and warmth are wasted because the crop has run short of its raw material. CO₂ enrichment solves this directly: by dosing carbon dioxide back into the greenhouse air, concentrations are lifted to levels where photosynthesis — and therefore growth and yield — measurably increases. For many crops it is one of the most cost-effective yield levers available.

The source of that CO₂ is itself a design decision with real economic weight. Where a combined heat and power (CHP) unit is installed, its cleaned exhaust gases are rich in CO₂ and can be captured and delivered to the crop — turning a by-product of generating heat and electricity into a valuable input, the essence of the Dutch approach of making every stream do more than one job. Alternatively, liquid CO₂ is bought in, stored and vaporised on demand: simpler and cleaner, but a direct running cost rather than a recovered by-product.

The real subtlety is that enrichment and ventilation pull in opposite directions. The crop needs high CO₂, but it also needs cooling, and the moment the vents open to release heat, the enriched air — and the money spent creating it — escapes with it. The climate computer therefore weighs dosing against ventilation losses hour by hour, enriching hardest when the greenhouse is closed and light is plentiful, and easing off when the vents must open, so CO₂ is spent where it does the most good rather than blown out of an open window.

Getting that balance right — the source, the delivery system and the control strategy — is what turns CO₂ from a cost into a return. DutchGreenhouses® designs the enrichment system and integrates it with the heating, CHP and climate-control strategy so photosynthesis is fed efficiently across the whole day. Get in touch to design CO₂ enrichment for your greenhouse.