Performances de cinq capteurs d'humidité relative de l'air

Three "second generation" and two "first generation" relative humidity (RH) sensors were installed in a 150 m² glasshouse with variable temp. and humidity and compared over a 12 month period. Readings were taken every 5 min and data was stored on the hard disk of a PC. The sensors were required to operate in extremely varied and severe climatic conditions. The "first generation" sensors proved unreliable at high temperatures or humidities. The "second generation" sensors performed very well with a few extremely rare malfunctions. The functioning error over a 12 month period, as a percentage of RH, was calculated for each sensor. The "second generation" sensors showed considerable errors of measurement at RH<30%, though this is unimportant for horticultural uses. The 3 sensors of this type were considered suited and reliable for RH measurement in a horticultural glasshouse. A list of manufacturers and distributors of relative humidity sensors is included. / Comparaison de cinq capteurs d'humidité relative de l'air dans une serre. Deux de ces capteurs sont de l'ancienne génération. Cette étude est réalisée suite à une demande des professionnels de l'horticulture et de l'ADEME.