Ermittlung der optimalen CO2-Düngung mittels chemisch gebundener Kohlenstoffdioxid Medien für den Kultivierungsprozess innerhalb der MEPA (Mobile Entfaltbare Pflanzenanbaueinheit)

Abstract

In the context of this bachelor thesis the optimal CO2 fertilization by means of chemically bound carbon dioxide media for the cultivation process within the MEPA (Mobile Deployable Plant Cultivation Unit) is determined in a self-built test stand. In the future, the MEPA system is to be used in crisis areas and inhospitable regions to enable the cultivation of fresh fruit and vegetables. Several students at the DLR Bremen site are developing the MEPA for this purpose. By increasing the CO2 concentration in greenhouses it is possible to increase the biomass production of certain plants by up to 30%. For this reason, CO2 fertilization will also be used in the MEPA. There are several possibilities of CO2 fertilization, some of which are described in this bachelor thesis. Four of these possibilities were investigated in detail in a self-built experimental stand with regard to their CO2 release into the ambient air. The experimental stand was manufactured from an old server cabinet. Aluminum profiles were installed in these and high-pressure laminates were used for the front, top and rear sides. A through hatch was installed in the front of the experimental stand. On the rear six sensors were mounted in four sensor boxes in four bushings. These were two CO2 sensors, two temperature sensors and two sensors for relative humidity. LabVIEW 2012 software was used for data processing. The hardware consisted of a power supply, two modules with four channels each, and a chassis from National Instruments. A water pump was used to pump water through a hose into the experimental stand during the experiments. Before the tests were started, the experimental stand was checked for leaks. A sufficient tightness for the test was determined. Seven tests were carried out with four different media in powder form, which were then analyzed and discussed. The evaluation of the results showed that citric acid with sodium bicarbonate releases the most CO2 into the ambient air. In addition, the simple processing and rapid chemical reaction of the substrate mixture when in contact with water make it the optimum fertilizer for use in MEPA from the fertilizer options tested in this paper. Finally, a conclusion was drawn about the construction of the test stand and the test executions as well as an outlook for improvement possibilities and hints for future research activities.