Bifacial Outdoor Rotor Tester- BIFROT

Transcription

1 Bifacial Outdoor Rotor Tester- BIFROT Markus Klenk, Miyazaki, bifi PV 2016

2 BIFROT-Motivation There is still considerable uncertainty about the actual benefit due to bifaciality Bifacial module yield is dependent on multiple factors Available measurement data often from stand-alone modules Field data from existing, real installations Rare Assignability to systems with differing set-up? Other ground albedo? Simulations are semi-quantitative at best, if available at all Yield of installations can not be predicted with sufficient accuracy Potential investors are deterred and rely on conventional monofacial lay-out General issue: Bankability Installer, planner : What are the optimized installation conditions?

3 BIFROT-Motivation / Examples Impact of mounting conditions Optimum tilt angle dependent on Module elevation Albedo / ground Latitude (system layout, e.g. vertical) Oslo Simulation issues Limited accuracy - Example PVSyst, E/W, 1 module, vertical PVSyst: Bifacial not considered Vertical bifi: constructed Low simple situation Elevation variation no effect Cairo U. A. Yusufoglu, Analysis of the Annual Performance of Bifacial Modules and Optimization Methods, IEEE J. Photovoltaics, vol. 5, no. 1, pp , 2015

4 BIFROT-Motivation / Examples Impact of mounting conditions in array Direct shading Indirect (reduced albedo) Extreme: Vertical mounting Varied distance, albedo, width Benefit of bifacial?

5 BIFROT-Goals Provide more general data than test field with fixed conditions Variable conditions (tilt, albedo, height, distance, ) Real world conditions; array instead of single module Systematic compilation of data in long-term measurements Increase bankability by generation of reliable data at system level Reveal optimized installation conditions Verify simulation tools and improve calculations Analyze specific properties of bifacial modules / systems Angular sensitivity, intensity distribution at rear,

6 BIFROT Set-Up Array instead of single module test rig Real world conditions as in actual bifacial PV system Variable parameters (albedo, height, distance, width - manually) Continuously varying tilt angle (automated) Focus on central module(s) => Expansion of 3x3 to 3x4 array

7 BIFROT Set-Up Continuous tilt variation - all rows 1 cycle in 60 seconds 0 to stops during each cycle 12 IV-curves of central module(s) Tracking of ambient data Other positions may also be used Continuous long-term measurement Remote control

8 BIFROT Set-Up

9 BIFROT Set-Up Currently installed 9 pcs. Megacell 280 Wp BiSoN-Cells ISC Constance Mounting for 60 cell standard Framed or frameless Dimensions: Some flexibility

10 Measurement Equipment Pyranometer (tilt & Reference cell (tilt & Wind (direction, speed) Temperature (amb. & mod.) Rear side sensors (later) Camera (clouds or system monitoring)

11 Measurement Example: Daily Summary Central module(s): 12 IV-curves / minute Summary daily / Ambience data

12 Measurement Example: Insolation Example: Comparison of different insolation conditions Differing insolation and influence of tilt angle Relative intensities: 0 tilt 100% intensity Tilt angles: 0, 10, 15, 18, 21, 25, 30, 35, 40, 45, 60, 90 sunny partly cloudy covered

13 Measurement Example: Data Analysis Long-term measurement result in huge amount of data Condensing data is challenging task Example: Mapping of yield vs. tilt and horizontal global irradiance for one day [1] F. Baumgartner et. al. 22nd EUPVSEC, 3-7 September 2007, Milano, Session 4DO.4.6

14 Measurement of General Properties Analysis of general properties Example: Intensity rear Small cells around rim Non-uniform intensity!

15 Miniaturized Test Rig / Basic Idea BIFROT: Long term measurements Reveal yield; Compile data for simulation Manual adjustment (height, dist., albedo) slow Miniaturized rig - more flexible solution? Param. varied quickly nearly identical conditions Multiple cheap rigs vary at identical conditions!!! Multiple cheap rigs directly compare locations!!!

16 Miniaturized Test Rig / Correspondence

17 Miniaturized Test Rig / Correspondence

18 Miniaturized Test Rig / Correspondence

19 Miniaturized Test Rig / Correspondence Prerequisite: Is there a clear correspondence BIFROT miniaturized rig The miniaturized rig shows a surprisingly good suitability to predict the output and the yield of real installations with bifacial modules! To be checked: Temperature dependence of Rseries FF correction factor?

20 Miniaturized Test Rig Flexible Pre-Test of Concepts Idea: Test reflectors with different shapes Does reflector shape have an effect on power generation? May be useful to suppress soiling of flat reflector (ground) Test of six reflector types black, flat 0 white, flat 0 white, flat 15 white, flat 30 white, parabolic 15 white, parabolic 30 Long-term test to reveal yield or Quick scan of differing set-ups at virtually identical lighting conditions

21 Miniaturized Test Rig Flexible Pre-Test of Concepts Here: Quick change of reflectors at virtually unchanged lighting conditions Snapshot for specific conditions (noon) no statement about yield yet + height + distance Obvious -> delta black to white / delta lowest at best monofacial orientation Low / steep tilt angles -> incr. albedo impact Flat white reflector -> good for low tilt angles / curved reflectors -> superior at 60 Vertical -> reduced effect of reflector shape

22 Summary and Outlook BIFROT: Superior to a test field with fixed conditions Variable parameters at real world conditions Systematic analysis of general properties (e.g. intensity distribution at rear) Ongoing: Long-term measurements to enable Reliable statements about bifacial device yield in real installation Bankability, Data for potential investors, Reveal optimized installation conditions, Test and improvement of simulations Miniaturized device: Surprising correspondence to BIFROT results More flexible: Measure different set-ups at virtually unchanged conditions Use more than one: Direct comparison of set-ups at identical conditions Use more than one: Direct comparison of set-ups at different locations