Characterising the Solar Resource with a Temporal Direct Normal...
Transcript of Characterising the Solar Resource with a Temporal Direct Normal...
Characterising the Solar Resource with a Temporal Direct Normal Irradiance
Topograph
Preyen Perumall, Jean Pitot and Mike BrooksGroup for Solar Energy Thermodynamics (GSET)
Mechanical EngineeringUniversity of KwaZulu-Natal
2nd Annual STERG SolarPACES SymposiumStellenbosch University
July 2014
GSET © 20141
Overview:
1. Solar furnaces
2. GSET solar furnace requirements
3. Assembling solar measurement data
4. Temporal Direct Normal Irradiance Topograph (TDT)
5. Applications of the TDT
Characterising the Solar Resource with a Temporal Direct Normal Irradiance Topograph
GSET © 2014Group for Solar Energy Thermodynamics 2
GSET © 2014
Characterising the Solar Resource with a Temporal Direct Normal Irradiance Topograph
• Solar furnaces concentrate solar energy to deliver high thermal fluxes onto a target area
• Harness direct normal irradiance (DNI)
• High temperature materials testing, evaluating CSP receiver technology, photochemistry experiments and solar fuels
Paul Scherrer Institute Solar Furnace
3Group for Solar Energy Thermodynamics
Characterising the Solar Resource with a Temporal Direct Normal Irradiance Topograph
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• GSET to perform CSP equipment testing
• 5-10 kW total power output requirement
• 2.5 – 3 MW/m2 peak flux
• Maintaining control over flux at the target area is a challenge
• Characterise the available solar resource for Durban
4Group for Solar Energy Thermodynamics
• Collating DNI measurements for Durban and Stellenbosch
• SAURAN data
• Visual inspection method is used to extract clear-sky days
• Interested in seasonal and daily characteristics of clear-sky days only.
Characterising the Solar Resource with a Temporal Direct Normal Irradiance Topograph
GSET © 20145Group for Solar Energy Thermodynamics
Characterising the Solar Resource with a Temporal Direct Normal Irradiance Topograph
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Durban’s TDT
Stellenbosch’s TDT
DN
I(W
/m2)
Superimposed TDT
6Group for Solar Energy Thermodynamics
Stellenbosch
Durban
• Comparing the TDT to less complex radiative model approximations of DNI
• Cross-section analyses of the TDT to setup an operational envelope
• TDT as an input to optical model of the solar furnace
Characterising the Solar Resource with a Temporal Direct Normal Irradiance Topograph
GSET © 2014
DN
I(W
/m2)
7Group for Solar Energy Thermodynamics
Durban TDT
(Measured)
ASHRAE
Hottel
Fu Rich
Kumar
𝐷𝑁𝐼 = 𝐸0. 𝑇𝑏𝑚𝑓
Bulk atmospheric transmittance
Characterising the Solar Resource with a Temporal Direct Normal Irradiance Topograph
GSET © 2014
Durban
8:00AM
Stell.
8:00AM
Durban
10:00AM
Stell.
10:00AM
8Group for Solar Energy Thermodynamics
January December
Characterising the Solar Resource with a Temporal Direct Normal Irradiance Topograph
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Durban
Day 20
Stell
Day 20
Durban
Day 175
Stell
Day 175
9Group for Solar Energy Thermodynamics
Future Work
• Expanding total number of clear-sky days used in generating the TDT.
• Improve the clear-sky detection method.
Conclusion
• The TDT is a time-based, empirically derived map of DNI with a high temporal resolution of 1 minute.
• Aid in the design and site suitability analyses for installation of CSP technologies.
Characterising the Solar Resource with a Temporal Direct Normal Irradiance Topograph
GSET © 201410Group for Solar Energy Thermodynamics
Characterising the Solar Resource with a Temporal Direct Normal Irradiance Topograph
GSET © 2014
Acknowledgments
• Eskom Tertiary Education Support Programme (TESP)
• Stellenbosch University – Solar Thermal Energy Research
Group (STERG)
• National Research Foundation (NRF)
11Group for Solar Energy Thermodynamics