Hi, I am the engineer who designed Vaportrol™ technology. (@jane passed this to me) The short answer is no. There is no reservoir. The system maintains Vapor Pressure by regulating moisture loss and not over drying. We don’t use humidifiers or dehumidifiers. This is totally new technology in the industry.
Vapor pressure is the measurement of water vapor pressure. The more water there is in a volume air, the higher the Vapor Pressure. The pressure is typically measured in millibars (mb). You can use Pounds per Square Inch (PSI) but the values are really low. For example, if our Dry/Cure box is set to 70F and 50% RH the vapor pressure in the box will be ~ 18.0mb, if you convert it to PSI, it would be ~0.26 psi.
A wet bud’s vapor pressure can be measured with a scale of Water Activity (aw). The more water that is in the bud, the higher the vapor pressure of the bud. The difference between the vapor pressure in the box, as compared to the vapor pressure of the bud, determines the rate that the water will leave the bud, which translates into the time it takes to dry the bud.
Letting the water come out of the bud at just the right rate is key to really well dried buds. Once you are in the cure phase, you want the vapor pressure in the box to match the vapor pressure of the bud. You want to slow, if not stop the drying process, to allow the awesome flavors and characteristics to develop.