S08 - Session P5 - Pulsed Optimal ratio between yield and energy reduction

Authors: Sabine Wittmann *, Ivonne Jüttner, Heike Mempel

In the future indoor vertical farming will become a year-round supplier of high-quality raw plant materials and an important addition to conventional cultivation methods. As a result, interest in this innovative form of production has been increasing for years both in the media as well as among producers, manufacturers and suppliers, data analysts and investors worldwide. However, there are still challenges to establish indoor vertical farming as a profitable system, as the investment and running costs are particularly high. The greatest challenge for profitability is the high energy consumption, which is primarily required for lighting (approx. 50%) and air conditioning (approx. 30%). One possibility to reduce the electrical energy consumption is the use of pulse width modulated LEDs. However, the vast majority of the available studies did not quantify the specific effect of pulsed LEDs on the electrical energy consumption of an indoor farm in relation to LED lighting. Furthermore, there is only limited information available to identify a duty ratio that is as low as possible, with at least the same yield and quality. According to earlier simulations based on physiological measurements with several combinations of frequency and duty cycle a reduction of up to 30 % seems feasible. The plausibility of these findings and their applicability to a running system will be verified by further experiments on French beans. In addition to morphological and physiological differences and efficiency parameters, there is a special focus on yield and optical quality properties. The experiment will be carried out in the indoor vertical farm at the University of Applied Sciences Weihenstephan-Triesdorf.