Large shell structures for power generation technologies

Wilfried B. Krätzig, Reinhard Harte, Ralf Wörmann:

IASS – IACM 2008 • 6th Int. Conference on Computation of Shell and Spatial Structures 28 – 31 May 2008 • Cornell University, Ithaca, NY, USA

1. Natural draft cooling towers and solar updraft chimneys: Why large?

2. Natural draft cooling towers: Construction principles • loading and internal stress variables • shape optimization • instability and vibrations • damage and life-duration

3. Solar updraft power plant chimneys: Construction principles • shell strength versus ring stiffening • instability and vibrations

4. Conclusions

Actual cooling tower projects made of high-performance concrete in Germany

From high natural draft cooling towers to solar chimneys

Krätzig & Partner Ingenieurgesellschaft für Bautechnik mbHK & P 08/3-30

From natural draft cooling towers to solar chimneys

Solar GreenTower Competence Network®

W.W. Stinnes M.Sc.(Phys.), Haiger (Germany) und Pretoria (RSA)

Prof. Dr. R. Harte, U. Wuppertal + Krätzig & Partner, Bochum

Prof. Dr. Dr. E.h. W.B. Krätzig, Ruhr-University + Krätzig & Partner, Bochum

Prof. Dr. H.- J. Niemann, Ruhr-Universität und Niemann & Partner, Bochum

Prof. Dr. D.G. Kröger, University of Stellenbosch, RSA

Prof. Dr. T.W. von Backström, University of Stellenbosch (RSA)

Prof. Dr. G.P.A. van Zijl, University of Stellenbosch und T.U. Delft

Dr. V. Wittwer, ISE Fraunhofer Institut für Solare Energiesysteme, Freiburg

Prof. Dr. J. Meins, T.U. Braunschweig

further research institutes and industrial enterprises from different countries

Annual global solar radiation (kWh / m2)Yellow areas – more than 1950 kWh / m2

o Red areas – more than 2200 kWh / m2

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Krätzig & Partner Ingenieurgesellschaft für Bautechnik mbHK & P 08/3-45

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Sun

Collector Area CA Turbine

Ground Generator coupled to the turbine PCU

Solar Chimney SC

Schematic solar chimney power plant

Prototype solar chimney power plant Manzanares, Spain (1982), prototype project Prof. J. Schlaich

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Solar Chimney

32 Turbine openings Ø 31 mCollector roof

Krätzig & Partner Ingenieurgesellschaft für Bautechnik mbHK & P 08/3-31

Natural Hazard Resistant Design of the Green Tower

Krätzig & Partner Ingenieurgesellschaft für Bautechnik mbHK & P 08/3-33

GreenTower Project Namibia: Tower foot alternative

32 Additional StiffeningWalls d = 2.0m

32 TurbinesØ 31 m

Artist’s view of large solar chimney power plant

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Large shell structures for power generation technologies

Wilfried B. Krätzig, Reinhard Harte, Ralf Wörmann:

IASS – IACM 2008 • 6th Int. Conference on Computation of Shell and Spatial Structures 28 – 31 May 2008 • Cornell University, Ithaca, NY, USA

1. Natural draft cooling towers and solar updraft chimneys: Why large?

2. Natural draft cooling towers: Construction principles • loading and internal stress variables • shape optimization • instability and vibrations • damage and life-duration

3. Solar updraft power plant chimneys: Construction principles • shell strength versus ring stiffening • instability and vibrations

4. Conclusions

Krätzig & Partner Ingenieurgesellschaft für Bautechnik mbH BochumK & P 08/4-15

NDCT RWE Lignite Power Plant Neurath 2007

Krätzig & Partner Ingenieurgesellschaft für Bautechnik mbH BochumK & P 08/4-13

NDCT RWE Lignite Power Plant Neurath 2007

Krätzig & Partner Ingenieurgesellschaft für Bautechnik mbHK & P 08/3-29

Lignite power station Neurath in boundary wind tunnel

Krätzig & Partner Ingenieurgesellschaft für Bautechnik mbHK & P 08/3-29

Gust modeling in the wind tunnel

Krätzig & Partner Ingenieurgesellschaft für Bautechnik mbH BochumK & P 08/4-8

NDCT Vattenfall Lignite Power Plant Boxberg 2008

Krätzig & Partner Ingenieurgesellschaft für Bautechnik mbH BochumK & P 08/4-23

NDCT RWE Lignite Power Plant Neurath 2007

Large shell structures for power generation technologies

Wilfried B. Krätzig, Reinhard Harte, Ralf Wörmann:

IASS – IACM 2008 • 6th Int. Conference on Computation of Shell and Spatial Structures 28 – 31 May 2008 • Cornell University, Ithaca, NY, USA

1. Natural draft cooling towers and solar updraft chimneys: Why large?

2. Natural draft cooling towers: Construction principles • loading and internal stress variables • shape optimization • instability and vibrations • damage and life-duration

3. Solar updraft power plant chimneys: Construction principles • shell strength versus ring stiffening • instability and vibrations

4. Conclusions

Krätzig & Partner Ingenieurgesellschaft für Bautechnik mbHK & P 08/3-41

Small solar tower of 500m of height

Krätzig & Partner Ingenieurgesellschaft für Bautechnik mbHK & P 08/3-36

Meridional (n22w ) and in-plane shear (n12w ) forces, 500m tower

Krätzig & Partner Ingenieurgesellschaft für Bautechnik mbHK & P 08/3-37

Instability modes: 500m tower without stiffenings rings (G+W+S)

Krätzig & Partner Ingenieurgesellschaft für Bautechnik mbHK & P 08/3-38

Instability modes for 500m tower with 4 stiffenings rings (G+W+S)

Artist’s view of large solar chimney power plant

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cooling towers to solar chimneys

Krätzig & Partner Ingenieurgesellschaft für Bautechnik mbHK & P 08/3-30

From high natural draft cooling towers to solar chimneys

Maximum Electrical Power OutputFirst semester - 21st of each month

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• Plastic covered water tanks• Provide more uniform daily power output profile (static control)• Relatively shallow tanks• Covered with transparent plastic (no water evaporation)• Black inside bottom• Insulated outside bottom and sides (no heat losses to environment)

Regulating plant power output according to demand (cont.)

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Reference plant (Jun)Reference plant (Dec)1/2 Area water tanks (Jun)1/2 Area water tanks (Dec)3/4 Area water tanks (Jun)3/4 Area water tanks (Dec)Full Area water tanks (Jun)Full Area water tanks (Dec)

• Plastic covered water tanks• Partially covered collector area, constant tank depth• Significant static control• 2.4% (1/2 Area), 2.7% (3/4 Area), 2.6% (Full Area) reduction

in annual power output

Regulating plant power output according to demand (cont.)

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• Dynamic control• Base or peak power

generation facility• Inclusion of additional

collector roof• Inclusion of airflow

regulating mechanisms• Plant given ability to store

or release energy when needed

• Base load strategy• Keep power as

constant as possible• Peak load strategy

• Maximum power delivered between 07:00 and 12:00 and 17:00 and 22:00 (Eskom)

Regulating plant power output according to demand (cont.)

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• Double glazed secondary collector roof• Base load: excellent control• 7.9% increase in annual power output

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Reference plant (Jun)Reference plant (Dec)Plant with DG SR (Jun)Plant with DG SR (Dec)

Regulating plant power output according to demand (cont.)

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Reference plant (Jun)Reference plant (Dec)Plant with SR (Jun)Plant with SR (Dec)

• Secondary collector roof• Peak load: good control• 2% increase in annual power output

Regulating plant power output according to demand (cont.)

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Krätzig & Partner Ingenieurgesellschaft für Bautechnik mbHK & P 08/3-25

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200mNiederaußem

300mEiffelturm

800mBurj Dubai

1500mGreen Tower

Solar Chimney

32 Turbine openings Ø 31 mCollector roof

Krätzig & Partner Ingenieurgesellschaft für Bautechnik mbHK & P 08/3-31

Green Tower Project Namibia

Krätzig & Partner Ingenieurgesellschaft für Bautechnik mbHK & P 08/3-33

GreenTower Project Namibia: Tower foot alternative

32 Additional StiffeningWalls d = 2.0m

32 TurbinesØ 31 m

Krätzig & Partner Ingenieurgesellschaft für Bautechnik mbHK & P 08/3-32

1000m tower for a 200MW SCPP

Krätzig & Partner Ingenieurgesellschaft für Bautechnik mbHK & P 08/3-43

Solar Chimney Project Arabia: 1000m variant

Krätzig & Partner Ingenieurgesellschaft für Bautechnik mbHK & P 08/3-39

Instability modes of 1000m tower for G+W+S

Krätzig & Partner Ingenieurgesellschaft für Bautechnik mbHK & P 08/3-40

Vibration modes of 1000m tower

Krätzig & Partner Ingenieurgesellschaft für Bautechnik mbHK & P 08/3-46

Vibration modes 1, 2 and 3 of 750m tower

3rd vibration mode f3 = 0.50 Hz

1st vibration mode f1 = 0.17 Hz

2nd vibration mode f2 = 0.34 Hz

Krätzig & Partner Ingenieurgesellschaft für Bautechnik mbHK & P 08/3-47

Vibration modes 4, 5 and 6 of 750m tower

4th vibration mode f4 = 0.77 Hz

5th vibration mode f5 = 0.77 Hz

6th vibration mode f6 = 0.84 Hz

Large shell structures for power generation technologies

Wilfried B. Krätzig, Reinhard Harte, Ralf Wörmann:

IASS – IACM 2008 • 6th Int. Conference on Computation of Shell and Spatial Structures 28 – 31 May 2008 • Cornell University, Ithaca, NY, USA

1. Natural draft cooling towers and solar updraft chimneys: Why large?

2. Natural draft cooling towers: Construction principles • loading and internal stress variables • shape optimization • instability and vibrations • damage and life-duration

3. Solar updraft power plant chimneys: Construction principles • shell strength versus ring stiffening • instability and vibrations

4. Conclusions: When will SUPCs be improved structures like NDCTs?