MICROCLIMATE CONTROL IN GREENHOUSES BASED ON PHYTOMONITORING DATA AND MOLLIER PHASE DIAGRAM

At present, there are only a few aids available for estimating the physiological and economical efficiency of the greenhouse climate, which concerns the set-up of optimal air temperature and humidity conditions. By using phytomonitoring technology, climatic conditions could be evaluated with the help of information’s from the plant itself. Firstly, a diagrammatic method of the representation of the connection between temperature and humidity is necessary to measure climatic conditions. Secondly, information about the optimal setup is required. For this a method to describe optimal ranges of microclimate for increasing light use efficiency inside the plant canopy was developed based on Mollier-h,x-Diagram. The next step was the development of an enthalpy balance model for prediction of condition point changes inside the phase diagram for water vapour. For this measured and calculated changes of air condition are compared. In an experimental production greenhouse for tomatoes (Lycopersicon esculentum), measurements were obtained with a phytomonitoring system that selected data from the microclimate and plants. Synchronous the influence of technical equipment like ventilation, heating and fog system on the microclimate was examined using mollier phase diagram. In result a good agreement between measured and calculated course of state of the air condition based on enthalpy balances was found. With this a tool for high precision control of temperature and humidity as very important growing factors inside the plant canopy is available.