CO2 Controller for Plant Growth Chambers

A new technology for controlling the partial pressure of CO₂ (pCO₂) in a plant growth chamber (PGC) has been demonstrated. CO₂ is gathered from the source atmosphere across a membrane gas exchanger and stored in an alkanolamine solution. The CO₂ loading of the alkanolamine reservoir is monitored using specific conductance and controlled by the exposure time and temperature. The PGC pCO₂ is maintained using a second membrane exchanger through which the alkanolamine circulates, absorbing or releasing CO₂ to maintain equilibrium. The equilibrium pCO₂ is determined by the CO₂ loading and the temperature. Constant PGC feed pCO₂ levels of roughly 1000 ppm have been maintained using sources with pCO₂ both above and below this value.