Departement Megan iese en Megatron iese
Department o f Mechanica l and Mechatronic Eng ineer ing
Design of a Pump
Microhydro System
Departement Megan iese en Megatron iese Ingen ieurswese
Department o f Mechanica l and Mechatronic Eng ineer ing
Design of a Pump-As-Turbine
Microhydro System for an Abalone
Farm
BH Teuteberg
March, 2010
Ingen ieurswese
Department o f Mechanica l and Mechatronic Eng ineer ing
Turbine
for an Abalone
Design of a Pump-As-Turbine
Microhydro System for an Abalone
Farm
Final Report for Mechanical Project 878
BH Teuteberg
Supervisor: Prof W van Niekerk
Department of Mechanical and Mechatronic Engineering
Stellenbosch University
March, 2010
i
I, Bernhard Hein Teuteberg, declare that I have not accepted outside help
regarding the project, either from fellow students or from anybody else.
___________________
Bernhard Hein Teuteberg
___________________
Prof. W. Van Niekerk
ii
ABSTRACT
This document details the design process of a 97 kW microhydro system for
Roman Bay Sea Farm in Gansbaai in the Western Cape Province of South Africa.
It contains a literature study of microhydro power, with a focus on the use of
Pump-as-Turbine technology and direct-drive systems. The literature study leads
to several possible concepts for the project, which are then evaluated and the
most suitable design is found to be a reverse running pump that powers a
different pump through a direct drive system. Experimental data from KSB is
used to test the accuracy of various correlations that can be used to generate
turbine-mode operation curves from pump curves. The final design parameters
for the complete system are then determined, and presented along with a cost-
benefit analysis.
OPSOMMING
Hierdie verslag dokumenteer die ontwerpsproses van n 97 kW mikro hidro
stelsel vir Roman Bay Sea Farm in Gansbaai in die Wes Kaap van Suid Afrika. Dit
bevat n literatuurstudie van mikro hidrokrag, met n fokus op Pomp-as-Turbine
en direk-gekoppelde stelsels. Die literatuurstudie lei tot n aantal moontlike
konsepte vir die projek wat dan evalueer word sodat die mees gepasde ontwerp
gekies kan word. Dit word gevind dat n pomp wat verkeerd om hardloop en n
ander pomp direk van krag voorsien die mees gepasde ontwerp is.
Eksperimentele data van KSB word gebruik om die akkuraatheid van verskeie
korrelasies te toets wat gebruik kan word om turbine-mode gedrag van pomp
kurwes te bepaal. Die finale parameters van die hele stelsel word dan bepaal en
word dan saam met n koste-analise aangebied.
iii
CONTENTS
Page
Abstract .................................................................................................................... ii
Opsomming .............................................................................................................. ii
List of Figures .......................................................................................................... iv
List of Tables ............................................................................................................ v
List of Symbols ........................................................................................................ vi
List of Subscripts and Acronyms ............................................................................. vi
1. Introduction .................................................................................................... 1
2. Literature study .............................................................................................. 3
2.1 Microhydro systems ........................................................................... 3
2.2 Water filtering .................................................................................... 3
2.3 Penstock ............................................................................................. 4
2.4 Turbine ................................................................................................ 5
2.4.1 Typical turbines .................................................................. 5
2.4.2 Pump-as-Turbine (PAT) ...................................................... 7
2.5 Power ................................................................................................ 13
2.5.1 Generator ......................................................................... 13
2.5.2 Linked PAT and pump ...................................................... 15
3. Computer simulation .................................................................................... 18
4. Current setup and future expansion at Roman Bay ..................................... 23
4.1 Pump models and average flow rate ............................................... 23
4.2 Outflow ............................................................................................. 24
4.3 Future expansion .............................................................................. 24
4.4 Proposed site to investigate ............................................................. 25
5. Concept evaluation ...................................................................................... 26
6. System design ............................................................................................... 34
6.1 Turbine selection .............................................................................. 34
6.2 Driven pump section ........................................................................ 37
6.3 Specification of remaining components ........................................... 37
7. Project costs ................................................................................................. 41
8. Summary....................................................................................................... 44
9. References .................................................................................................... 45
Appendix A: Fluid property determination ........................................................... 48
Appendix B: Turbine cost prediction formulas ...................................................... 49
Appendix C: BUTU method for predicting PAT performance from pump
performance data ......................................................................................... 50
Appendix D: Performance factor diagrams from the method of Chapallaz et al.
(1992) ........................................................................................................... 51
Appendix F: Pump and Turbine mode curves of various KSB centrifugal pumps . 54
iv
LIST OF FIGURES
Figure 1: Slanted box cleaning system (Cunningham & Woofenden, 2007) and
Leaf mulcher (Aronson, 2008) ................................................................................. 4
Figure 2: Rough guide to turbine type operating ranges (adapted from Chapallaz
et al. 1992) ............................................................................................................... 5
Figure 3: Types of impulse turbines (Western North Carolina Renewable Energy
Initiative, 2007) ........................................................................................................ 6
Figure 4: Low Head turbines .................................................................................... 6
Figure 5: Turbine Operation vs. Pump Operation Characteristic curves
(Baumgarten & Guder, 2005) .................................................................................. 7
Figure 6: Choice of pumps for PAT applications (adapted from Chapallaz et al,
1992) ........................................................................................................................ 8
Figure 7: "C-2C" Three phase induction motor connection .................................. 14
Figure 8: Linked shaft PAT/pump system in Java, Indonesia (Baumgarten &
Guder, 2005) .......................................................................................................... 16
Figure 9: Assembled linked shaft PAT/pump system Indonesia (Baumgarten &
Guder, 2005) .......................................................................................................... 17
Figure 10: Inlet loss coefficients ............................................................................ 21
Figure 11: Screenshot of the simulation program ................................................. 22
Figure 12: Map of Roman Bay showing important areas ...................................... 23
Figure 13: Outlet water flow .................................................................................. 24
Figure 14: Outlet water channel ............................................................................ 25
Figure 15: Overview of design decisions to be made ............................................ 28
Figure 16: The four different concepts considered for this project ...................... 29
Figure 17: Concept design of system ..................................................................... 34
Figure 18: Correlation results versus experimental results ........................
