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Modern Environmental Science and Engineering (ISSN 2333-2581) August 2018, Volume 4, No. 8, pp. 702-711 Doi: 10.15341/mese(2333-2581)/08.04.2018/002 Academic Star Publishing Company, 2018 www.academicstar.us

Design of Microturbines Kaplan and Turgo for Systems: Challenges and Adaptations

Teresa Maria Reyna, Santiago Reyna, María Lábaque, César Riha, Belén Irazusta, and Agustín Fragueiro Faculty of Exact, Physical and Natural Sciences, National University of Cordoba, Argentina

Abstract: The mini-hydraulic systems can be used in all cases where a watercourse is available, even if small, with a fall of even a few meters. The introduction of hydroelectric mini-systems has a reduced impact since the majority use of the watercourse, which may be vital for the provision of isolated areas, is not modified. Mini-hydraulics is the term that is used for hydroelectric plants of less than 10 MW. Hydroelectric mini-plants are simple, environmentally friendly and useful for near-installation applications. They require a few components: turbine group — generator — and a regulatory system. In order to accelerate the implementation of alternative systems in rural areas, and to make this a standard practice, it is necessary to develop equipment adapted to the conditions of the area; and adapt them for their progressive production in local industries. There is an unmet demand for reliable equipment that can supply small amounts of at low cost. In this context, three projects with the aim of to designing micro turbines have been developed at the National University of Córdoba with the objective of establishing the feasibility of construction and development with local technology.

Key words: microturbines, microgeneration systems, , micro hydroelectric

[1]. Development needs a socially and physically 1. Introduction balanced environment, but the consequences of climate As defined by the National Oceanographic and change are not making it possible. Thus, the Atmospheric and Administration (NOAA), climate consequences of in the economies, in change consists of long-term fluctuations in the population and in the are indicators that temperature, precipitation, wind, and all other aspects if the current trajectory is maintained, the negative of the Earth’s climate. The United National Framework consequences will probably increase [2]. Convention on Climate Change describes the The Intergovernmental Panel on Climate Change [3] phenomenon as a change of climate global atmosphere, in its Special Report on Renewable Energy Sources and and that is, in addition to natural climate variability, Climate Change Mitigation (SRREN) analyzes observable over comparable time periods. estimates on the installation of renewables in various Climate change and energy are two sides of the same scenarios, considering that in most of the 164 cases coin: much of the (GHG) emissions analyzed there will be a significant increase in the come from the energy sector in its various forms deployment of renewable energy in the horizons of (including transport). That is why the solution to the 2030 and 2050. In this case, more than half of the problem involves a fundamental change in the energy scenarios assume that renewable will system, which will largely only be possible with a represent a production of more than 17% of total greater participation of renewables in the by 2030, increasing to more than 27% in 2050. In fact, the most optimistic scenarios raise the Corresponding author: Teresa Maria Reyna, Dr.; research areas/interests: renewable energy. E-mail: previous figures to 43% in 2030 and 77% in 2050. [email protected].

Design of Microturbines Kaplan and Turgo for Microgeneration Systems: Challenges and Adaptations 703

The causes of climate change are found in current also be affected. However, there are adaptation options. production and consumption patterns. The further we Significant cuts in GHG emissions can be achieved go in the fight against CC (climate change), the more through various measures from the energy sector. we will have to on the economic and social These include reducing emissions from the extraction elements. Likewise, it happens with the effects of CC, and conversion of fossil , switching to less carbon the deeper they are, the more they will affect society fuels (for example, from to gas), improving energy and the economy. However, the impacts of climate efficiency in transmission and distribution, the change in our region are already expected, which is increasing use of energy renewable energies and the why it is essential to make progress in the adaptation generation of nuclear energy, the introduction of process that reduces the risk of the most vulnerable carbon capture and storage (CCS), and the reduction of population and at the same time admits the reduction of final energy demand. There is a growing awareness of poverty and inequality levels. The regional projections, the environmental effects of the current system of under different scenarios, indicate that it is necessary to economic development, such as climate change, acid profoundly modify the forms of production, or the hole in the ozone layer. distribution and consumption in order to move towards Changing the behavior of the big emitters of carbon economic systems that generate less CO2 emissions. As is one of the keys to success in addressing climate can be inferred, placing the economies of the region on change because fewer than 20 countries are responsible the path of low emissions requires facing a difficult for 80% of the world´s carbon emissions. Changing the transformation in the industrial sectors, especially behavior of the emitters has been fraught with those that consume the most energy. problems [4]. To adapt to such an important increase in the role of Modern societies, which sustain their growth in an renewables, especially in the sector, energy based mainly on obtaining energy systems must evolve considerably. In the long term, through fossil fuels, are increasingly inclined towards integration efforts could include investment in the adoption of measures that protect our planet. This is infrastructures, modification of institutional reflected in current national policies and international frameworks and planning, and capacity to forecast the agreements and treaties that include as a priority growth of these energy sources. The development of objective a that does not electric vehicles, the increase in electric cooling and compromise the natural resources of future generations heating, the flexibility in demand (smart meters), the [5]. storage of energy, among other phenomena, can be Much of the technology that dies and will underpin associated with this trend [1]. sustainability is based on science that is still evolving. A new field, sustainability science, is preparing the 2. Electric Energy and Climate Change foundations for technological development that Climate change presents increasing challenges for parallel the general intent of sustainability. Some of the the production and transmission of energy. The endeavors include work on: resilience, progressive increase in temperature, the increasing industrial ecology, earth system complexity, number and severity of extreme weather events and the yield-enhancing, land-saving , change in precipitation patterns will affect the nature-society interactions, renewable energy systems production and supply of energy. and biomimicry, to name but a few [6]. The supply of fossil fuels, and the generation and The promotion of renewable energy technologies transmission of thermal and hydroelectric energy, will offers a double advantage: energy diversification and

704 Design of Microturbines Kaplan and Turgo for Microgeneration Systems: Challenges and Adaptations the hope of development for many poor and isolated may require additional political support and imply communities that are not connected to the grids of higher costs [8]. transport and electrical distribution. The supply of Mitigation policies can create under-exploited energy to isolated communities is conceived as support sectors of activities linked to , such as energy for their productive, domestic and commercial efficiency, renewable energies, water reuse and uses of activities. Consequently, it is considered as a strategic water of different quality according to their destination. component within a framework for development work 3. [7]. In Córdoba, a few years ago, the power available in Hydroelectricity is a mature technology. Hydraulic the is lower than the peak electricity turbines have global efficiencies of around 90%, at demand. In turn, the rural population is 11.3% of the their highest efficiency point. This distinguishes them population of the Province and 6% is in isolated areas. from other sources of energy. 30% of the rural population is considered not to be What is new about hydroelectricity has to do with connected to the electricity distribution system. That is where to apply it, on which scale, and how to solve the why, in particular, the development and study of problem the generation matrix, that is, how it is linked certain energies in principle with high potential in the to other alternative energy systems. province are of interest: mini and micro However, its evolution has not come to an end; but hydroelectricity, wind energy, , instead it is being adapted to the needs for clean energy, energy and hydrogen as energetic vector, inherently since the sites available require more compacted associated with the use of these energies as a common turbines and works with smaller impact [8]. denominator. Experimental small-scale micro-hydraulic The development of renewable energies is the development is not common since hydroelectric foreseeable consequence of a look at the energy issue generation is considered an unprofitable activity. As a from the perspective of sustainability. Within this result, lower efficiencies are obtained relative to those paradigm, researchers and those responsible for energy obtained in comparison with larger plants. The and the environment play a fundamental role in alternatives of decentralized generation and small generating its dissemination and bringing technology powers are not yet used in a meaningful way to meet closer to the population. The promotion of renewable these demands. energy technologies offers a double advantage: energy 4. Hydraulic Turbomachines diversification and the hope of development for poor and isolated communities that are not connected to the The theoretical analysis of the turbomachines is grids of transport and electrical distribution. The carried out assuming negligible the effect of friction supply of energy to isolated communities is conceived load loss and considering an incompressible fluid. as support to productive, domestic and commercial For a turbomachine, if the velocity of the fluid is activities and is considered as a strategic component decomposed so that the velocity u1 is the absolute within a framework of work for development. velocity of the vane at the inlet or outlet, ci, the absolute

Expanding the use of renewable energy in the of the fluid, wi, the relative velocity of the fluid with electricity mix could lead to an increase in the respect to the vane, cim, the meridional component of challenges associated with the integration of power the absolute velocity of the fluid, ciu, the peripheral generation facilities within the network. There are component of the absolute velocity of the fluid, αi, the technical options to meet these challenges, but they angle formed by the two velocities ci and ui and βi the

Design of Microturbines Kaplan and Turgo for Microgeneration Systems: Challenges and Adaptations 705

angle formed by wi with -ui. These three speeds c1, u1 and w1 are related according to the mechanics of the relative movement according to Eq. (1): =− wcu111 (1) Given the second form of the Euler Eq. (2). uu22−−− ww 2222 cc H =+12 2 112 + (2) u 222ggg

The dynamic height that the fluid gives to the impeller is the third term of the previous equation, that Fig. 1 Turbine impulse vs reactions. is to say: cc22− the turbines, the Pelton, Turgo and cross-flow turbines ± 12 (3) will have a GR = 0, while the Francis and Kaplan 2g turbines will have a GR> 0. while In impulse turbine the steam flows through the uu22−− ww 22 nozzle and strikes on the moving blades. In reaction 12+ 2 1 (4) turbine steam first flows through the guide mechanism 22gg and then flows through the moving blades. is the pressure or static height of the impeller. Energy change is verified by a mutual action (action 22− The term ()/2uu12 gconstitutes the static and reaction) between the walls of the blades and the charge due to the centrifugal action or inertial reaction fluid [11]. of the fluid produced by the normal acceleration At any point in the trajectory of a particle you can created with the drag of the fluid by the blades in their draw the axes r, according to the radius, u, according to rotation around the axis of the machine [9]. the tangent and a, according to the axis of the machine: The degree of reaction of a turbine refers to the way In the radial machine, the axial speed is zero in all the impeller works and is the relation between the the points of the impeller (Rarely found among hydraulic turbines). pressure energy Hp and the total energy Hu, defined according to the equation In the axial machine, the radial velocity is zero at all points, thus: u1 = u2 H GR = p (5) In the radioaxial machine, the speed has the three Hu components (Francis) In Pelton turbines, the flow is merely tangential. If the degree of reaction is 0, that is 0, the machine is called action or impulse. Pelton turbines are used on medium to high head If GR > 0, the turbine is reactive by having a sites with heads from 20 up to pressure component in its energy. hundreds of metres. Power outputs can range from a There are two basic steam turbine types, impulse few kW up to tens of MW’s on the largest utility-scale turbines and reaction turbines, whose blades are Pelton systems. Because the operating head is high, the designed control the speed, direction and pressure of flow rate tends to be low, ranging from 5 litres/second the steam as is passes through the turbine (see Fig. 1) on the smallest systems up to 1 m3/s on larger systems. [10]. According to the classification given to each of The relatively low operating flow rate is not a problem

706 Design of Microturbines Kaplan and Turgo for Microgeneration Systems: Challenges and Adaptations because the terrain required to achieve the heads must be hilly or even mountainous, and these are typically high-up in a catchment so the catchment area, and hence flow rate, is small. According to the estimated characteristics of the jump and flow and the power needed, it is possible to identify the type of turbine and the most suitable size (see Table 1 [12]) for use in micro hydroelectric uses. In the case of micro-systems there are models that apply to the conditions of the place or to the possibilities that exist for its installation. The differences between the machines are linked to the best Fig. 2 Turbine application chart. use that can be made of the energetic potential of water to generate . During the year 2010-2012 we worked on the Each type of turbine can only operate with flows development of a Michael Banki turbine, which was between the nominal (for which performance is the designed and built entirely in Cordoba workshops in a maximum) and the technical minimum, below which it 1:1 scale. This machine is currently installed in the is not stable [13]. Hydraulic Laboratory of the Faculty of Exact, Physical The choice of a type of turbines will depend on the and Natural Sciences of the National University of estimated characteristics of jump and flow of the area Córdoba, and has encouraged the interest of many of location and the power that is needed. The Fig. 2 [14] professionals and students who for the first time have shows a diagram that shows the recommended regions contact with a micro turbine. for different types of hydraulic turbines based on these For the construction of the different elements of the physical characteristics of water courses. turbine, a series of tools, such as bending machines, shaping machine, milling machines, numerical control 3. Methodology lathe, etc. were used. All the pieces that are in contact To accelerate the application of alternative systems in with water (rotor injector set) were subjected to a hot rural areas, and to make this a normal practice, it is zinc surface treatment to extend their life span. Both necessary to develop adequate equipment, adapt them the rotor and the injector were made of SAE 1020 steel. for progressive production in local industries, and The development of the Michael Banki turbine project establish a financing system in collaboration with local has generated an important impulse in the theme of the banks to assist to potential users and owners. There is an use of renewable energies in our City and has unmet demand for robust and reliable equipment that encouraged the development of linked local research can supply small amounts of energy at low cost [8]. groups to improve the technological development of this energy generation area. Table 1 Classification of hydroelectric power plants During the 2014-2015 period, a second project was according to their power. Micro also financed by the Secretariat of Science and Region Institution Mini central Small central central Technology of the National University of Córdoba 101-2000 2000-10000 Word ONUDI1 < 100 kW kW kW (SECYT), where the engineering of a Latin OLADE2 < 50 kW 51-500 kW 500-5000 kW was developed, developing machine engineering. From America 1. United Nations Organization for Industrial Development. the projects and developments carried out, practical 2. Latin American Energy Organization. information can be obtained of its simplicity, operation

Design of Microturbines Kaplan and Turgo for Microgeneration Systems: Challenges and Adaptations 707 and maintenance; allowing to incorporate renewable allows to work in channels that have intermediate energies within the possibilities for the solution of jumps but with low flow rates, in order to offer the problems of this type. In particular, there are currently local market a new alternative to the different graduates from the graduate and postgraduate areas conditions of each location. who worked during the development of both projects Within this framework, in addition, progress is being and now enter the labor market with information and made in the transfer of technology in the area of familiarity with the type of machines developed [15]. renewable energies. Work is currently being done with But the development of two types of microturbines the secondary school Instituto Técnico Cristo Obrero at the local level continues to limit its use to specific de Carlos Paz in the construction of the Kaplan turbine cases. The development of different machines allows to in order to incorporate the subject into the middle level expand the spectrum of application opportunities for of education. In addition, an agreement has been signed which it is necessary to incorporate other types of between the Faculty of Exact, Physical and Natural machines. As a next step towards the diffusion of these Sciences in collaboration with said school to continue turbines, a Turgo-type turbine was developed that working jointly.

Fig. 3 Michel Banki turbine built in the year 2012.

Fig. 4 Images of the machining of the Kaplan Turbine at the Cristo Obrero School, 2017.

708 Design of Microturbines Kaplan and Turgo for Microgeneration Systems: Challenges and Adaptations

which facilitates its performance and increases the 4. Micro Turbine Axial speed of the fluid (water), these characteristics make The Kaplan micro turbine is a machine classified as these turbines are built with very small impeller a reaction, inlet and axial flow turbine. It is used mainly diameters. for small hydroelectric uses and also has the advantage Choosing not to use aerodynamic blades but curved of being simple design, which makes it attractive for a blades of constant thickness came to meet one of the small scale use. This type of micro turbines can be main requisites of the possible use of propellers for installed on small leveling in rural areas. micro-turbines, which is to be able to produce them in The impeller is composed of a few blades, which local workshops. This choice, regarding the blades, give it the shape of a ship’s propeller; when they are produce a lower lift coefficient and higher resistance, fixed, it is called a turbine propeller, whereas if they are so that together the efficiency is less. It does not fully adjustable, they are called Kaplan turbines; In both utilize the energy exchange from the fluid to impinge cases, the turbines operate with a single direction of on the vanes, either. But the losses are not important if rotation; they are therefore irreversible turbines. they are compared with the ease of manufacture and Its main features are: maintenance [8]. • Reduced dimensions. 5. Turbine Turgo • Relatively high speeds. • High performance with variable load. The Turgo , is another impulse type • Remarkable capacity for overloads water turbine design in which a jet of water strikes the The machine that was developed seeks to produce at turbines blades. The turbo turbine design is similar to least one megawatt. The flow rate considered is 0.1 the Pelton Turbine wheel but this time the water jet m3/s and a net height of 5 m. With these values, from the nozzle strikes a series of curved or angled considering a yield of approximately 60%, we obtain a blades instead of cups or buckets from the side at a useful power of approximately 3 kW. shallow angle of about 20° instead of tangentially so In these machines the profile of the blades has that the water hits the angled blade from one side and hydrodynamic characteristics with little curvature, exits on the other.

Fig. 5 Figure of the axial turbine.

Design of Microturbines Kaplan and Turgo for Microgeneration Systems: Challenges and Adaptations 709

It is a motor turbomachine action, free jet, radial longitudinal plane that contains the axis, as occurs in a flow. It has several advantages over the Pelton turbine. This modification will bring with it a and the Pelton turbine in certain applications. The variation in the angles of entrance of the fluid, impeller is cheaper to make than to Pelton, it does not considered optimal. need a hermetic casing like the Francis, it has a higher The absolute speed of water input in the injector for specific speed and can handle a greater flow for the an action machine is given by: same diameter as a Pelton turbine. CK= *2** gH (6) The distributor consists of an injector 1 C of the type that projects a jet of water inclined with Where Kc is the velocity coefficient at the exit of the respect to the axis of the Rodete, in an angle of 15° to injector due to losses therein, it ranges between 0.97 22.5°. and 0.99 (0.976 is adopted). As the flow of the water through the turbines wheel The dimensioning of the spoons is the most enters at one angle and exits at another, the flow of the important part of the turbine. Its construction must be incoming jet of water is not hindered by the exiting able to withstand the maximum thrust caused by the jet waste water, as is the case with Pelton turbines, when the turbine is stopped, and the maximum allowing for a higher flow rate. centrifugal force when the impeller is packed. Also due to this higher flow rate, a Turbo turbine can Due to the structural conditions of the machine the have a much smaller diameter than an equivalent turbine was designed with 16 spoons with a step of Pelton for the same amount of power output allowing 22.5°. them to rotate at higher speeds. However, the Turgo The Fig. 6 [16] shows the plane of the turbine. wheel is less efficient than the . 6. Conclusions The impeller resembles Pelton half impeller, as if it were divided by a plane that passes through the edges The development of renewable energies is the of the spoons and is perpendicular to the axis. foreseeable consequence of a look at the energy issue Next, the main elements that make up the projected from the perspective of sustainability. The promotion Micro Turbine are described and the steps to follow for of renewable energy technologies offers a double correct sizing are: advantage: energy diversification and the hope of • Calculation of usable power. development for poor and isolated communities that • Euler equation and speed triangle. are not connected to the grids of transport and electrical • Injector Project. distribution. • Blades of the Rodete. The advantage of the micro hydroelectric plants • Turgo Turbine Project distributed over the territory is not so much the energy For the calculation of the power, the performance of contribution that can be given to the national electricity the hydroelectric uses in this scale of 60% was need, but the value of the use of the water resource at considered. In the case of the study, it was 1.53 kW, so the local level, taking into account that hydroelectric it is a central micro. energy is a type of hydroelectric power. Renewable Due to the particular characteristics of the Turgo energy with minimal environmental impact if the water Turbine, in the hydraulic design of it, the principle of force is used without damaging it. maximum use of energy (in relation to the ratio of The projects that framed the studies presented in this speeds) must be modified. This is due to the fact that work on generation sought to apply simple the water does not enter completely parallel to the technologies of clean hydroelectric energy without

710 Design of Microturbines Kaplan and Turgo for Microgeneration Systems: Challenges and Adaptations

Fig. 6 Figure of turbine Turgo. damming, low cost that allowed its construction and should be a stimulus to continue. installation to apply to various isolated communities The developed project sought to apply simple and that was incorporated into society through of the technologies of hydroelectric clean energy without link with the new generations. The interest is to damming, low cost that allowed its construction and develop each of the machines to see the complexity of installation to apply it to isolated communities. each one and to carry out the construction and later the As a result of the study, two types of turbine were installation to allow decentralized electricity supply developed: a Kaplan turbine and a Turgo. The that would allow replicating it in other communities development of the Kaplan turbine project was that due to their characteristics cannot or is very complete, reaching its current construction at the Cristo expensive to link to national interconnected system and Obrero School and, on the other hand, the design of a whose diffusion can be supported both by the private Turgo turbine which is complete at project level and public sectors. waiting to be mechanized when the school ends with The link developed with a secondary technical the previous one. school allows professionals and researchers to transmit The interest of these projects seeks to collaborate their knowledge to society and generate technological with policies that avoid the emigration of isolated areas, developments at local levels. In addition, it shows that given that Córdoba and other provinces currently suffer the challenge posed is a path that deserves to be from internal immigration from rural areas to urban traveled and that the passion shown by the students areas. One of the reasons for this is the lack of access to

Design of Microturbines Kaplan and Turgo for Microgeneration Systems: Challenges and Adaptations 711 the electrical system which does not allow them access [5] Cambridge Institute for Sustainability Leadership (CISL), IPCC Climate Science Business Briefings: Based on the to technology, communication and education that IPCC Fifth Assessment Report (AR5), 2017, available exists in the cities. online at: http://www.cisl.cam.ac.uk/ipcc. [6] Keen Meg, Brown Valerie A. and Dyball Rob, Social List of Simbols Learning in Environmental Management: Towards A Sustainable Future, Earthscan, 2005, p. 270. u absolute speed of the blade at the entrance or at 1 [7] T. Reyna, S. Reyna, M. Lábaque, C. Riha and E. the exit Giménez, Aplicaciones de Usos de Energías Renovables: ci absolute speed of fluid Microturbinas de Generación Hidroeléctrica, in: XXV Congreso Latinoamericano de Hidráulica S. J., Costa wi relative velocity of fluid with respect to the vane Rica, 9 al 12 de septiembre de 2012. c meridional component of the absolute velocity of im [8] T. Reyna, S. Reyna, M. Lábaque, C. Riha and F. Groso, the fluid Applications of small scale renewable energy, Journal of ciu peripheral component of the absolute velocity of Business and Economics (2016). the fluid [9] M. Polo Encinas, Turbomáquinas Hidráulicas, México, α LIMUSA, 1976. i angle formed by the two speeds ci and ui [10] Electropedia, Battery and energy technologies, available βi angle formed wi with -ui online at: http://www.mpoweruk.com/steam_turbines.htm. Kc speed coefficient at the exit of the injector [11] C. Mataix, Turbomáquinas Hidráulicas: Turbinas d nozzle outlet diameter hidráulicas, bombas, ventiladores (1st ed.), Universidad Pontificia Comillas, 2009. d0 diameter of the jet [12] T. Reyna, M. Lábaque, S. Reyna, C. Riha and B. Irazusta, Diseño de Microturbinas Kaplan y Turgo para Sistemas References de Microgeneración. Desafíos y Adaptaciones, in: XXVI [1] X. Labandeira, P. Linares and K. Würzburg, Energías Congreso Nacional Del Agua Córdoba, Argentina, 2017. Renovables y Cambio Climático – Econmics for Energy. [13] J. Fernández Mosconi, O. Audisio and A. Marchegiani, WP 06/2012, 2012, Consultado Noviembre de 2016. Pequeñas Centrales Hidráulicas. Apuntes de clase, [2] NU.CEPAL, Sustainable Development in Universidad Nacional del Comahue, Facultad de and the Caribbean: Follow-up to the United Nations Ingeniería, Neuquén, Argentina, 2003. Development Agenda beyond 2015 and to Rio+20, Ed. [14] Available online at: https://en.wikipedia.org/wiki/ ECLAC, 2013, p. 139. Water_turbine. [3] IPCC (Intergovernmental Panel on Climate Change), [15] T. Reyna, M. Lábaque, S. Reyna, C. Riha and B. Irazusta, Special Report on Renewable Energy Sources and Energía mini y micro hidráulica: aporte contra el Cambio Climate Change Mitigation, 2011. Climático, JIA2017. [4] Ch. Kibert, L. Thiele, A. Peterson and M. Monroe, The [16] T. Reyna, M. Lábaque, A. Fragueiro, F. Fulginiti, B. Ethics of Sustainability, 2009, available online at: Irazusta and C. Riha, Informe SECyT, Universidad https://www.researchgate.net/file.PostFileLoader.html?id Nacional de Córdoba, 2017. =574ae7fadc332dae991230cd&assetKey=AS%3A36706 6331795458%401464526841856.