Efficient horticulture requires more than lighting and fertilizers alone. Plants need additional CO2 for vigorous growth. Horticulture greenhouses produce their own CO2 in the process of burning natural gas for heating and lighting. TNO has developed a buffer to allow the CO2 produced at night to be used in the daytime, using little energy, based on a natural equilibrium process.
When using assimilation lighting, crops need extra CO2 in the daytime for improved plant and fruit growth. Instead of buying CO2 from a supplier, horticulture greenhouses can use the CO2 produced by the combined heat and power (CHP) installation at night. TNO has developed a temporary store, or buffer, for this purpose. The process stores CO2 in a zeolite framework. When no CO2 is needed, hollow chambers in the framework trap CO2 molecules from the flue gasses as they pass through. When extra CO2 is needed, the trapped molecules are released from the zeolite by passing dry ambient air through the framework. The trapping and later releasing of CO2 using zeolites exploits a natural equilibrium process. TNO and various partners ran a demonstration project to show how energy-efficient, sustainable and inexpensive this CO2 dosing method is. The next step is to scale the process up.