Fig. 25: Used kWh in the different chambers

A higher dry substance was involved with a higher sugar content. Sonata had a lower dry substance and a lower sugar content than Magnum.

4.4 Economics

4.4.1 Lighting hours

The number of lighting hours is contributing to high annual costs and needs therefore special consideration to consider decreasing lighting costs per kg marketable yield. The total hours of lighting during the growth period of strawberries were both simulated and measured with dataloggers.

The HPS chamber had a daily usage of 189 kWh (Fig. 25), while the LED chamber had with 106 kWh nearly 45 % less than the HPS chamber.

Fig. 25: Used kWh in the different chambers.

The simulated value was calculated according to the lighting hours written down. However, there it was not adjusted for automatic turn off, when incoming solar radiation was above a set-point (Tab. 6). Therefore, the simulated value was higher.