Development of a method for condensation rate measurement on flat surfaces

Abstract

Condensation on greenhouse interior surfaces plays an important role in reducing indoor air humidity. There is no standard method to measure condensation rate in greenhouses or in any other buildings. In this study, a commercially available leaf wetness sensor was calibrated in an environment chamber under different room temperature and RH conditions, which included five temperatures of 18, 20, 22, 24, and 26 °C, and five RH levels of 40, 55, 65, 75, and 85%. The sensor surface temperature was maintained the same as the room temperature. Room temperature water was sprayed on the sensor surface, simulating condensate. The voltage output of the sensor changed due to varying amounts of condensate on the sensor surface. The amount of condensate on the sensor surface was divided into five groups from 0 to 0.5 g (or 0–0.015 g per square centimeter of sensor surface area) with an interval of 0.1 g. The statistical analysis showed that both sensor temperature and indoor RH had no significant effect on the sensor voltage output. The voltage output was solely determined by the amount of condensate mass on the sensor surface. A linear regression model was developed between the voltage output and the amount of condensate. This tool is considered as a breakthrough of technology for condensation rate measurement on greenhouse interiors surface, or on any other surfaces with condensation. Anyone can use this sensor and the development relationship for measuring condensation rate as the sensor is not pricy and the method is easy to use, thus the method should be widely used as a standard method. Keywords: Condensation sensor, Leaf wetness sensor, Greenhouse