Mans optimises greenhouse with sensors

In September 2012, Gerbera grower Kees Mans in Brakel commissioned his new greenhouse. The greenhouse is 3.1 hectares and equipped with an installation for the New Cultivation (TNC). Boxes for external air (AHUs) have been installed, there are hoses under the crop and there is a double screen.

In the context of the ‘Klimaat monitoring (Climate monitoring)’ project from the Kas als Energiebron (Greenhouse as an Energy Source) the AgriSensys system was installed. This system consists of a set of wireless sensors, with which temperature, humidity and CO2-concentration can be monitored and a base station that sends the data to the Wireless Value server through an internet connection. Through this internet application their temperature and humidity differences can be depicted. The research is supervised by Climeco.

Fewer chinks

Mans says: “The New Cultivation is really a learning process. We are working hard gaining experience with the new system. Setting up all installations requires much more time than we initially thought. This spring we installed a set of sensors and found very surprising things. We were convinced that thanks to the overpressure we would have a homogeneous greenhouse climate. However, this appeared to not be entirely the case.”

At the Gerbera nursery there are four departments with a measuring box in the middle of each. The grower: “It appears that these measuring boxes provide insufficient information. With the sensors we were able to conclude that at some points there are still cold spots, mainly at the side of the facade. Hot air in the middle of the greenhouse pulls moisture upwards because of a chink in the screen. Here the air cools against the deck and there is a flow of air. This cold air then falls back down the facade. Sometimes there were temperature differences of more than two degrees Celsius. In the Gerbera nursery this is really not acceptable. With some changes in the New Cultivation system it is possible to minimise the number of places that a moisture chink in the screen cloth is necessary. Due to this it is possible to largely eliminate this inequality without the need for additional heating. In this way, we save even more energy.”

And not only that: “Fewer cold spots on the facade means that we have overall better quality, less crown rot and less Botrytis. Initially the sensors were installed for testing purposes, but I am now considering purchasing a set myself so as to continuously monitor what is happening in the greenhouse.”