Solar energy laboratory
On the roof of Satakunta University of Applied Sciences' new campus, you will find a solar electricity research system with more than 120 panels. System was built in the summer of 2017. There are more than ten different systems for studying the effects of installation angle, orientation and row spacing on energy supply among other things. The total power of the system is about 35kWpeak.
Batteries
In addition to the panels, the system has two battery packs to ensure the electricity feed to the laboratory of technology and to balance the consumption peaks.
The smaller of the batteries is the 9.6 kWh Lithium battery (LiFePO4), which is intended for use in the consumption range of detached houses. It is a complete commercial unit with a Kostal Piko BA inverter/charger at the center. The function of the inverter is to control all energy flows. A 7kW photovoltaic system with 26 panels is connected to this battery system.
The remaining systems are connected to a larger 72 kWh AGM battery. The battery contains 36 two-volt AGM batteries with a total voltage of 24V. Off the shelf components are used in the system and it can supply 24kW of power without interruption.
In the winter, six vertical panels that charge the large battery directly through its own controller (Victron Energy SmartSolar charge controller MPPT 250/100) enhance charging. The total power of the panels is 1620Wp.
Row spacing research
The row spacing research consists of five panel rows with a total of 35 panels. The two of the rows have panels horizontally and the remaining three rows have panels vertically. The distances between the rows vary to study the effect of shading.
The power of a single panel is 270Wp, that adds up to 1890Wp in single row. Each row of panels has its own small 1.5kW inverter (SMA Sunny Boy), so their individual output data can be easily stored.
Directional angle research
The directional angle research system includes 12 panels, each mounted at different mounting angles and facing different directions. Each panel has its own optimizer that finds the best power point. A central inverter (SolarEdge SE3000H) handles the connection to the mains. To determine the effects of incorrect installations, one panel is facing north and one is installed horizontally. The total power of the system is 3240Wp.
Solar Tracker and comparison panel
Both the tracker and the comparison panel are connected to the grid with their own microinverters (ABB Aurora Power One). The tracker moves in two directions and its logic calculates the position of the sun while turning the panel towards it. Energy production is compared to the production of the fixed comparison panel. The panels are Sanyo HIT 250Wp panels.
There is also another larger 4860kWp solar tracker installed to the parking lot in 2018. It has 18 panels and it operates in same principle as the small one. Its production is compared to other systems.
East-West research
The rest of the panels are part of east-west research. The systems test the effect of different connections and inverter types to the production. SMA Sunny Boy, SMA Sunny Tripower and Fronius Symo inverters are used. The East-West study has 47 pieces of 270Wp panels with a combined power of 12.7kWp.
Panels
The panels used in the systems are all similar SolarXon Amerisolar AS-6P brand for ease of comparison, only the small tracker and reference panel system has Sanyo HIT panels.
SolarXon Amerisolar AS-6P
| Max power | 270 Wp |
| Module efficiency | 16,3 % |
| Measures | 1640 x 992 x 40 mm |
| Weight | 18 kg |
Sanyo HIT 250 HD4E
| Max power | 250 Wp |
| Measures | 861 x 1610 x 35mm |
| Weight | 16,5 kg |
| Type | Mono and thin film |
Introduction of SAMK solar panels
