A visualization of the physical and thermal interactions between solar farms and the atmospheric boundary layer
Brooke Stanislawski
Mechanical Engineering
Wind Energy & Turbulence Lab
CS 6635: Spring 2019
CS 6635 Final Project Objectives
To develop and showcase visualization techniques of large-eddy simulation (LES) data of atmospheric boundary layer (ABL) flow through simplified solar farms.
To answer research questions about the momentum and thermal impacts of solar farms.
Background and Motivation
Research Background and Objectives
To increase efficiency of solar farms by reducing the temperature of solar panels through convective cooling.
Background: Large-eddy simulations
To solve for momentum: filtered incompressible Navier-Stokes equation
To solve for temperature: advection-diffusion equation
Produce large amounts of 3-D vector-field turbulence and scalar-field temperature data typically exceeding 20 GB
Background: LES Parameters
Tpv_sfc= 300 K
Tgrnd_sfc= 290 K
Tair= 280 K
1 km
Quantity | Units | Symbol | Value |
Domain Size | m | Lx x Ly x Lz | 6280 x 6280 x 1000 |
Number of gridpoints | - | Nx x Ny x Nz | 64 x 64 x 64 |
Grid spacing | m | dx x dy x dz | 10 x 10 x 1.5 |
Total Real Time | hrs | t | 3.09 |
Number of Timesteps | - | nt | 500,000 |
Background: LES Data
Output variables in binary:
Calculated variables
Post-processing takes place in Matlab: 4-D arrays (nx * ny * nz * nt)
Converted to ParaView compatible format with Matlab function vtkwrite()
Results and Discussion
Validation
Do the value ranges of the physical variables appear reasonable everywhere in the domain?
The value ranges of both velocity magnitude and temperature appear reasonable, while heat flux
requires further inspection.
Validation
Maximum temperatures appear on solar panel surface as expected, while maximum and
minimum heat flux appears nonphysical.
Momentum Impact
How does the flow respond to the presence of the solar modules?
Tools used:
Momentum Impact
Visualizations reveal lateral re-circulation developing in between rows, a behavior
that is difficult to capture with 2-D plots.
Heat and Momentum
Transfer Interactions
How is heat from the solar panels transferred throughout the domain?
Flow carries the heat upward on the sides of the solar panels, similar to the turbulent
behavior of wingtip vortices on an airplane wing.
Heat and Momentum Transfer Interactions
Critical heat transfer captured as heated air from above the second row soars upward due to turbulence.
Flow and temperature evolution in time
How does the air temperature respond to the heat source from the solar panels?
Average air temperature increases asymptotically from 280 K to 291.5 K
as a result of heat transfer from the solar panels.
Hot spots
Where are the hot and cold spots on a solar panel and how do these change with time and turbulence?
The outer edges of the solar panels remain cooler due to the turbulence generated at these edges.
Conclusions
Significantly improved visualization of complex 3-D simulation results:
Findings in support of, and in addition to, the hypotheses of the research project:
References
1] O. Dupre, R. Vaillon, and M. A. Green,Thermal Behavior of Photovoltaic Devices. Springer International Publishing, 2017.
[2] M. Chamecki, C. Meneveau, and M. B. Parlange, “A hybrid spectral/finite-volume algorithm for large-eddy simulation of scalars in the atmospheric boundary layer,”Boundary-Layer Meteorology, vol.128, no. 3, pp. 473–484, 2008.
[3] C. Hansen and C. Johnson,The Visualization Handbook. Elsevier,2005.
[4] U. Ayachit,The ParaView Guide: A Parallel Visualization Application.USA: Kitware, Inc., 2015.
Thank You
Validation
Validation reveals insights into model’s performance and limitations.
Momentum Impact
Where are the highest and lowest velocities?
Highest velocities observed after and aloft of the last row while lowest velocities appear
near the forward edge of the first row.
Thermal Impact
Where is the maximum heat flux iso-surface and what is the heat flux maximum value?
High heat flux is observed on the edges and on the second row of solar panels,
following the vertical motions.