High-resolution spatial and electrical modeling for efficient BIPV system design

Transcription

1 High-resolution spatial and electrical modeling for efficient BIPV system design Johannes Hofer, Arno Schlueter Architecture & Building Systems, Institute of Technology in Architecture, ETH Zurich 6th PV Performance Modeling and Monitoring Workshop Fraunhofer Institute for Solar Energy Systems ISE October 24 and 25, 2016 Freiburg Germany

2 Opportunities for BIPV and thin-film PV Growing opportunity for PV in buildings due to energy regulation (EU NZEB, MuKEn) Increasing efficiency and reduced cost of thin-film PV (CIGS, CdTe, OPV, etc.) Lightweight and flexible, partial transparency, different colors New integration possibilities (buildings, transport, consumer electronics, etc.) Low cost production and installation Source: Source: 2

3 BIPV Applications SwissTech convention center Adrian Smith + Gordon Gill Architecture 3

4 NEST HiLo Project HiLo building to be constructed in 2017 at NEST (EMPA, Switzerland) Leightweight integrated roof and floor Thin-film PV applications (curved roof modules, adaptive solar facade) Further information: 4

5 Challenges and Objective Challenges Non-uniform irradiance (due to partial shading or curvature) generates imbalance between PV cells and modules Performance of thin-film modules in partial shading and under curvature not well known No adequate design and planning tools Objectives Creating a modeling framework coupling high-resolution geometry, irradiance, electrical simualtion Compare and validate with experimental analysis Apply in context of NEST HiLo project 5

6 Modelling Workflow Weather data Electrical design Building parameters CAD model (Rhinoceros 3D/Grasshopper) PV geometry Module positioning Irradiance model (RADIANCE/DIVA) Shading calculation Module irradiance Electrical model (Matlab/Python) IV characteristics Power generation PV system parameters 6

7 Geometric Model and Shading Analysis Parametric model (Rhino/Grasshopper) to simulate PV modules on roof and facade Triangulation method for layout of PV strips Parameters: module dimension, module distance, strip orientation, etc. PV modules on the roof PV modules on the facade J. Hofer et al., Energy Science and Engineering, 4, 2, , 2016 A. Groenewolt et al., Int J Energy Environ Eng,

8 Irradiance Analysis Cumulative sky approach (Radiance): matrix of sky patch values using the Perez all-weather model and hourly weather data High resolution sky using the Reinhart sky patch subdivision Backward ray tracing to calculate irradiance on geometry Irradiance model with sub-cell resolution (same as the electrical model) Sun directions 8

9 PV Electrical Model Modules Cells split in sub-cells, simulated with one diode model Reverse breakdown Bypass diodes PV system Series-parallel interconnection of modules Distributed electronics (power optimizer or microinverter) J. Hofer et al., European Solar Energy Conference, Munich, Germany,

10 PV Module Layout Electrical layout parameters Cell dimension Cell arrangement and interconnection Module bypass diodes Designs investigated Commercial CIGS modules Modules defined by industrial partner J. Hofer et al., European Solar Energy Conference, Munich, Germany,

11 Performance in Partial Shading Measurement of I-V curves in various partial shading conditions Module design and shading pattern strongly affect power loss Lateral shading Longitudinal shading shaded lateral shaded not shaded not shaded longitudinal J. Hofer et al., European Solar Energy Conference, Munich, Germany,

12 Performance in Partial Shading Comparison of model vs. experiment (module 1) Further comparison model/experiment for other module designs and interconnected modules J. Hofer et al., European Solar Energy Conference, Munich, Germany,

13 Design of PV as Shading Element Parametric 3D design of different adaptive shading system configurations Horizontal louvers (1-axis) Vertical louvers (1-axis) Diamond pattern (2-axis) Calculate electric performance and optimize system design Module arrangement and spacing Cell orientation String interconnection Bypass diode integration Facade cover ratio (FCR) = module area / facade area J. Hofer et al., Energy Science and Engineering, 4, 2, ,

14 Design of PV as Shading Element Applied in context of Adaptive Solar Façade (ASF) project PV cell orientation and placement of bypass diodes strongly affect energy yield P. Jayathissa et al., European Solar Energy Conference, Munich, Germany, 2016 J. Hofer et al., Energy Science and Engineering, 4, 2, ,

15 Performance of Curved PV Modules Simulation of irradiance and power output of curved modules (design 1) Flat horizontal module for comparison J. Hofer et al., European Solar Energy Conference, Munich, Germany,

16 Performance of Curved PV Modules Flat horizontal: efficiency mainly determined by temperature Curved: mismatch of irradiance between cells leads to efficiency loss J. Hofer et al., European Solar Energy Conference, Munich, Germany,

17 Performance of Curved PV Modules Experimental measurements using digitally fabricated prototype with same predefined geomtery Very similar dependence of efficiency observed (for this module design) J. Hofer et al., European Solar Energy Conference, Munich, Germany, 2016

18 Application to HiLo Building J. Hofer et al., European Solar Energy Conference, Munich, Germany,

19 PV Module Layout Irradiance and electricity yield vs. orientation J. Hofer et al., European Solar Energy Conference, Munich, Germany,

20 PV System Electrical Design Simulate irradiance distribution between cells and modules Optimize electrical layout Power optimizers to balance mismatch J. Hofer et al., European Solar Energy Conference, Munich, Germany,

21 Conclusions Summary Framework for modeling of PV modules in non-uniform irradiance PV module and system layout strongly influences the performance Can be used for efficient system design Outlook Identify PV module designs less sensitive in partial shading / curvature Measurements with a full scale ASF and a section of actual HiLo roof Evaluate module level electronics to balance mismatch 21

22 Acknowledgement NEST HiLo team Industrial partner Sponsors w w w. f l i s o m. c o m Contact: hofer@arch.ethz.ch Architecture& Building Systems: 22