Rapp, Christoph

Zeiselmair, Andreas

English

Hydraulic Engineering Repository

Article, Published VersionRapp, Christoph; Zeiselmair, AndreasEducational concept supporting a renewable energiestraning school in africaHydrolinkVerfügbar unter/Available at: https://hdl.handle.net/20.500.11970/109252Vorgeschlagene Zitierweise/Suggested citation:Rapp, Christoph; Zeiselmair, Andreas (2014): Educational concept supporting a renewableenergies traning school in africa. In: Hydrolink 2014/4. Madrid: International Association forHydro-Environment Engineering and Research (IAHR). S. 110-113. https://iahr.oss-accelerate.aliyuncs.com/library/HydroLink/HydroLink2014_04_Vertical_Slot_Fishway.pdf.Standardnutzungsbedingungen/Terms of Use:Die Dokumente in HENRY stehen unter der Creative Commons Lizenz CC BY 4.0, sofern keine abweichendenNutzungsbedingungen getroffen wurden. Damit ist sowohl die kommerzielle Nutzung als auch das Teilen, dieWeiterbearbeitung und Speicherung erlaubt. Das Verwenden und das Bearbeiten stehen unter der Bedingung derNamensnennung. Im Einzelfall kann eine restriktivere Lizenz gelten; dann gelten abweichend von den obigenNutzungsbedingungen die in der dort genannten Lizenz gewährten Nutzungsrechte.Documents in HENRY are made available under the Creative Commons License CC BY 4.0, if no other license isapplicable. Under CC BY 4.0 commercial use and sharing, remixing, transforming, and building upon the materialof the work is permitted. In some cases a different, more restrictive license may apply; if applicable the terms ofthe restrictive license will be binding.110 hydrolink number 4/2014After briefly describing the educational conceptand the university collaborations the design of asmall hydro power plant for the power supply ofa vocational training school for renewableenergies is being presented. Educational ConceptA discovery starts with an observation. The bestproof for this thesis is the endlessly cited story ofthe apple falling down on Isaac Newton’s head.Newton, it is said, started thinking of why suchthings happen, eventually deriving mechanics.Tracing the train of thought even further back itwas Plato who deduced the anamnesis. Hestated that the immortal soul already knowseverything but forgets upon its birth. Humanshave to recall their notion through externaltriggers – percipience. Indeed, without evertaking notice of the stars mankind would neverhave derived the heliocentric system and theorbits.Hence, education in natural sciences shouldalways start with the observation, or the sensingin general, of the phenomenon. Through thenotion of what is going on one comprehendsand deduces interrelated theory. The findingshave to be thoroughly questioned and finallyapplied to certain problems (Rapp, 2012). Thisgoes along with a permanent comparison ofexperiments and theory.The approach has been implemented inhydraulics education at TUM. The followingexample stands for more than fifty simplehydraulic experiments developed for thisteaching purpose. The fundamental deductionof the equations is not neglected.Observe - A sluice gate is mounted onto acarriage with roller skates and placed onto aflume (see Figure 1). The carriage is fixed with asimple spring scale. When the water cycle ofthe flume is being started one can see that thecarriage moves downstream as the flow rateand water level increase. While the sluice gatemoves downstream the spring scale extends.However, at a steady state the sluice gate doesnot move any further. One can assume that theforces acting on the sluice gate are in balancewith the reacting force.Comprehend - Why has the carriage got to beheld? The flow must apply a horizontal forceonto the gate and the spring reacts with arestoring force in the opposite direction. Ideally,the force resulting from hydrostatic pressurehas been explained before through variousexamples like in (Rapp, 2012) so that everyoneis aware that the hydrostatic pressure increaseslinearly with depth. The outflux of momentumcan be experienced by the students holdingtheir hands in the flume upstream anddownstream from the sluice gate. While doingA depictive teaching concept for hydraulics and hydraulic engineering has been developed atTechnische Universität München (TUM). The concept’s principle is the process of perception.Itsfinal step is the application of the learnt subjects. In the framework of an initiative for internationalknowledge exchange founded at TUM the implementation of the gathered knowledge has beencarried out in several hands-on projects in developing countries. There, universities and local peoplehave been involved. EDUCATIONAL CONCEPT SUPPORTING A RENEWABLEENERGIES TRAINING SCHOOLIN AFRICABY CHRISTOPH RAPP AND ANDREAS ZEISELMAIR EDUCATIONFigure 1 - A sluice gate is mounted onto a carriage with roller skates and placed onto a flume111hydrolink number 4/2014almost 600 million people without access toelectricity in total plus approximately the samenumber in Developing Asia; in Latin Americathere are still 24 million people without power(IEA, 2013). Since energy is the precondition forsocio-economic progress as it forms the basisof education, basic social and health servicesas well as economic growth, this fact heavilyreduces chances of local development. On theother hand the above mentioned regions havean enormous potential for small hydro powerplants. In Western and Middle Africa the instal-lation/potential ratio is 11% and 23% respec-tively, whereas Western Europe reaches 87%(Liu, et al., 2013).One of the integrated projects that werefollowed in the framework of the initiative is thedesign of the electricity supply for a vocationaltraining school for renewable energies at thenorthern foothill of Foumban, Cameroon (Rapp,et al., 2012a). The project’s scope is diverse.Firstly, the generated electricity shall supply theschool and its workshops with electricity.Secondly, people living close to the plannedplant who do not have access to the power gridshall be connected to satisfy their basic needs.Thirdly, a curriculum for renewable power gener-ation with theoretical and practical lessons shallbe created for the vocational school. And finallythe plant is meant to serve as an example forthe course. For these reasons an easy butdepictive layout is aimed for. The overallparadigm is an ecofriendly design. The feasi-bility of various renewable energy systems hasbeen assessed during a field trip. The highregional hydro power potential which is aconsequence of the reliable and extensiverainfall and the topography, the relatively lowcosts and the ecological friendliness havemade it first choice.Such projects can only succeed if futureassociates, residents and local authorities areinvolved from the beginning on. The peoplehave to identify themselves with the propositionand they have to be involved. Moreover,decisive concerns are legal and administrativeissues and yet knowledge of place. Additionally,the mutual exchange implies benefits andprecious experiences for both sides.Collaboration has been set up with ADEID, aBafoussam based non-profit organization. The proposed site is located in the proximity ofthe school plot where a small weir (max heightapprox. 1.5 m) already exists (see Figure 2). Inthe concept a 100 m long penstock with agross head of 8.5 m will feed a crossflowso one can even distinguish between sub- andsupercritical flow by watching the waves propa-gating. Deduce - In theory the forces acting on astructure can be determined with themomentum equation (1), of which LudwigPrandtl said (Prandtl, 1944):“The value of these momentum equations isthat they reveal conditions at the boundariesonly, so that one can reason phenomena thatare not comprehended in detail.”A volume fixed in space is being cut free and allforces acting onto that volume to keep it inplace and in shape are being marked on theflume’s wall. The volume has to be held againstgravity for instance or the flow has to bedeflected somehow. The forces can be derivedthrough the Cauchy equation. Question - In the present example the flume has got a width                 , an upstream flowdepth                    and a downstream flow depth. With a dischargethe spring force results               .(2)The spring scale shows a value of approx. 22 N,which complies in a reasonable manner with thecalculated restoring force; however, thequestion of the discrepancy pops up. Theanswer can be found in the experiment itselfagain. The carriage is not placed on the flumefriction free and also, in a lesser manner, thefriction losses of the flow have to be mentionedas well. The questioning of the deduction should becontinued with appropriate examples, e. g. therestoring force of a nozzle exposed to a flow.Apply - The application of the findings to newproblems is an essential part of the learningprocess.Apart from the application to certain assign-ments the practice of the comprehensiveknowledge within a concrete project ismandatory. To do so several hands on studentprojects have been done at TUM in collabo-ration with institutions in developing countries.One of these projects is being elaborated in thefollowing. Knowledge exchange – hydro powerprojectDeveloping countries face the challenge toprovide rural areas with electricity. According toofficial sources the rural electrification rate inSub-Saharan Africa is only 18.3% which impliesIAHRChristoph Rapp studied civilengineering at Technische UniversitätMünchen (TUM) and specialized inhydraulics and hydraulic engineering.He became research associate,developed a new educationalconcept, did fundamental and appliedresearch and founded the Associationfor International KnowledgeExchange. In 2009 he became head ofTUM’s hydromechanics laboratorythat he completely rebuilt. Hecurrently works for an energy supplierand is managing director of a hydropower company.Andreas Zeiselmair studiedgeography and environmentalengineering where he specialized inrenewable energies and hydraulics atTUM . He worked as an assistant atthe chair for hydromechanics and wasproject manager of small hydro powerprojects in Cameroon and Ecuador.He is co-founder of the social entre-preneurship initiative mobile hydrothat aims to empower people throughlow-cost hydropower. 113hydrolink number 4/2014IAHRturbine to generate about 15 kW (approx..120.000 kWh/a). A hydrological approach hasbeen developed to cope with the scarce dataavailable.Turbine - Various reasons have contributed tothe distinct decision for a crossflow turbine.They are robust, relatively unsophisticated, easyto maintain locally and, most importantly, theyare designed and optimized for these siteparameters.  Furthermore, crossflow turbinesdeal with comparatively low velocities whereforethey are not prone to sediment-inducedabrasion and cavitation. Constructional tasks - The weir capturingapprox. 10.000 m³ leaks at several spots (seeFig. 2) what makes an entire overhaulmandatory. An intake structure, the penstock onthe left embankment and a small power housewill be erected.Ecological and social impacts of the plant -Special emphasis has been placed on theecological and social impact and animprovement of the current situation. Thedimensions of the weir will stay untouched toexclude negative effects on flora, fauna andflood security. Endemic fish species likecyprinids and catfish will be prevented fromentering the penstock and the turbine by a finerack at the intake structure. What electricity means to people living in ruralAfrica can best be examined in WilliamKamkwamba’s book (Kamkwamba & Mealer,2009). The Malawi uneducated brilliant engineerhas brought electricity to his village by means ofa self-designed wind turbine made from scrap.Electrical power is the foundation of devel-opment and therefore the hydro power plant forthe supply of a vocational training center onrenewable energies is being regarded as a locallighthouse project.ConclusionIn this contribution an educational concept for aninternational knowledge exchange project hasbeen presented. The application of theorythrough a concrete hydro power project for thebenefit of the local population has been shown.Unfortunately, administrative decision for thehydro power plant has not been approved yet.Mutual support, knowledge exchange andcollaboration are the keywords of theAssociation’s projects conducted for instance in Jordan, Ecuador (see Fig. 3 and 4),Mozambique and Tanzania. For more information see: www.knowledgExchange.orgReferencesKamkwamba, W. & Mealer, B., 2009. The Boy Who Harnessed TheWind. s.l.:HarperCollins.Liu, H., Masera, D., Esser, L. & eds., 2013. World Small HydropowerDevelopment Report 2013, Vienna; Hangzhou: United NationsIndustrial Development Organization (UNIDO); International Centeron Small Hydro Power (ICSHP). Available from www.small-hydroworld.org.Prandtl, L., 1944. Führer durch die Strömungslehre. 9 ed.Braunschweig: Vieweg.Rapp, C., 2012. Forschung und Lehre im Hydromechanik-Labor derTechnischen Universität München. 2. überarbeitete und erweiterteAuflage ed. München: Fachgebiet Hydromechanik, TUM.Rapp, C., Zeiselmair, A., Lando, E. & Moungnutou, M., 2012a.Knowledge exchange and application of hydro power in developingcountries. Mauritius, Small Developing Island Renewable EnergyKnowledge and Technology Transfer Network.Williams, A. & Simpson, R., 2009. Pico hydro - Reducing technical risksfor rural electrification. Renewable Energy, pp. 1986-1991.Figure 2 - View onto the existing weir from downstream and overhaul measuresFigure 4 - Tibi, Ecuadorian Indigena carrying ashowcase model of a water wheel that illustratesthe functional principle of hydropowerFigure 3 - German and Cameroonian student surveying the site

Educational concept supporting a renewable energies traning school in africa

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Educational concept supporting a renewable energies traning school in africa

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