For almost 25 years, FCI’s constant power thermal flow meter technology has been the defacto, proven solution for moist gas applications such as WWT digester gas and other biogas. FCI’s constant power technology provides two key differences when compared to constant ΔT technology: 1) constant power is measuring a change in temperature which is slower to change and provides a natural dampening effect for moisture, and 2) the temperature difference at the sensors is 30°C to 50°C which creates a better drying effect on the sensors... Additionally, for moist, dirty gas applications, FCI flow elements provide open, equal mass sensors that will better shed the moisture and are most accessible for occasional cleaning (Figure 1).