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Hydro Power
Published in Sergio C. Capareda, Introduction to Renewable Energy Conversions, 2019
There are three types of water wheels: the overshot, the undershot, and the breast wheel. These are horizontal-axis water wheels used in earlier periods when simple rotating mechanical devices needed actuators. In overshot water wheels, the water is directed on top of the water-turning device. An undershot wheel has water directed to the bottom of the water-powering device. Breast wheels have water directed to the middle of the rotating device. Tub wheels are vertical-axis water wheels, with the impellers usually placed along the path of the river or stream. The rotating shaft protrudes vertically so that mechanical devices may be attached for whatever purpose. In the past, water wheels were used to power households for mechanical and rotating actions needed, such as for grain milling and grinding. Older sawmills in the United States also utilized water wheels for processing some agricultural products.
The Advent of Steam and Mechanical Engineering
Published in Ervan Garrison, A History of Engineering and Technology Artful Methods, 2018
Steam engines, the William Engine, coupled to generators operated under the formula, R = 60f/p, where R = rpm, f = frequency, and p = the number of poles of the generator. Using a steam turbine, a single pole generator running at 3000 rpm could replace a 300 rpm, 10-pole generator of the Williams type. In water-powered turbines, the horsepower available at any time is proportional to 1/19th the product of the head times the flow. Water-power systems, where stream flow is low in summer, became prohibitively expensive were large-storage reservoirs were required. Interconnection of steam plants with water plants allowed for the economical use of both steam power for “base load” (at or near capacity) with water power for “peak loads.” By 1921, interconnection was a standard practice. Water power supply peaked at 43% of 84 billion KW-hours in 1928. Steam-generators have been supplying the bulk of electricity ever since. Water wheels are 90% efficient where steam turbine plants waste 50–70% of the heat value of the fuel.
Chapter 2 The Water - Energy nexus
Published in Arcot Ganesh Pradeep Narrain, Low Head Hydropower For Local Energy Solutions, 2018
Hydropower is one of the oldest energy sources. In ancient times, water wheels were used to lift water or grind grain. In an early reference to water mills, the Greek poet Antipater describes the use of the machines to grind grain, thereby eliminating the need of young women to grind grain by hand. The earliest description of a water wheel is by the Roman engineer Vitruvius in the first century B.C. These water wheels were situated in or around settlements, providing a local power supply in the form of mechanical energy. The decline of hydropower began with the Industrial Revolution. Coal continued to be the primary energy carrier. The invention of the generator and of electricity enabled energy distribution. Coal became the primary energy source and a linking of power suppliers and consumers was enabled through a distribution network or electricity grid. The sheer size and number of coal power plants and the possibility to build them where energy was required gave this technology an edge over hydropower. The invention of the combustion engine fired by mineral oil increased overall power generation and enabled mobility. These decades of rapid advancement in industrialisation were accompanied by emissions resulting from the combustion of fossil fuels.
Optimization of undershot water wheels in very low and variable flow rate applications
Published in Journal of Hydraulic Research, 2020
Emanuele Quaranta, Gerald Müller
Gravity water wheels use the weight of water to generate power, i.e. the gravitational potential energy of the flow, and partially the kinetic energy of the flow. They are typically used in sites with heads between 0.5 m and 6 m (in some cases up to 8 m), with power output ranging from few kW to some tens of kW. Maximum hydraulic efficiencies of water wheels range between 70% and 90% (Müller & Kauppert, 2004). In particular, undershot water wheels are used in very low head applications, e.g. between 0.5 and 1.5 m, and maximum flow rates per metre width of about 800–1200 l s−1 (Quaranta & Müller, 2018). Two main types of undershot water wheels can be identified: the Zuppinger (Fig. 1) and the Sagebien wheel (Fig. 2). The Sagebien wheel has flat blades, with inclination chosen to minimize the inflow power losses, i.e. power losses when the blade enters into the upstream flow. The Zuppinger undershot water wheel has curved blades, designed to minimize the outflow power losses downstream of the wheel (Quaranta & Müller, 2018). Undershot water wheels generate power output that generally is below 30 kW, although the authors are aware of a Sagebien wheel 6 m wide that produces 110 kW (database in Quaranta & Revelli, 2018). However, their performance is still not completely optimized as for traditional turbines (e.g. Bozhinova, Kisliakov, Müller, Hecht, & Schneider, 2013; Müller & Kauppert, 2004; Quaranta & Müller, 2018).
Trends in an increased dependence towards hydropower energy utilization—a short review
Published in Cogent Engineering, 2019
Girma T. Chala, M. I. N. Ma’Arof, Rakesh Sharma
The main technologies used in a hydropower facility constitute dammed reservoir, running river, pumped storage, stream technology and new technology gravitational vortex [8]. In this regard, the research in Europe mainly focuses on the main elements of electromechanical equipments such as turbines, pumps and generators. Basically, there are two types of turbines: impulse and reaction turbines. There are three types of impulse turbines: Turgo, Pelton and cross flow turbines. However, most reaction turbines are of axial flow turbine (Kaplan turbine) type. Reaction turbines have better performance in low head and high flow sites compared to impulse turbines (Yaakob, Ahmed, Elbatran, & Shabara, 2014). The water flows via channel or penstock to a waterwheel or turbine where it strikes the bucket of the wheel, causing the shaft of the waterwheel or turbine to rotate. When generating electricity, the rotating shaft, which is connected to an alternator or generator, converts the motion of the shaft into electrical energy. World bank (WB: 2009) reported that hydropower would have important contribution to the efforts of the development and cooperation of region in scarce water resources (Vassoney, Mochet, & Comoglio, 2017). The inherent technical, economic, and environmental benefits of hydroelectric power make it an important contributor to the future world energy mix, particularly in the developing countries.
Mechanization in building construction projects: assessment and views from the practitioners
Published in Production Planning & Control, 2020
Bon-Gang Hwang, Ming Shan, Jaime J. M. Ong, Pramesh Krishnankutty
Mechanization has a long history which can be traced back to the Roman Period. At that time, the most representative mechanized equipment was water wheels, a device that was powered by flowing or falling water (Lienhard 2003). Mechanization did not receive a striking development until the early 1700 s, when the Industrial Revolution occurred. Along with the increasing use of steam engine at that point, a large number of metal parts were required by factories of different industries, which led to the invention of many machine tools in the late 1700 s until the mid-1800s (Cowan 2018). In the 1840 s, self-acting machine tools were developed, which displaced hand dexterity and allowed one unskilled worker to tend several machines simultaneously (Lazonick 1979). In the mid to late 1900s, hydraulic and pneumatic devices (e.g. pile drivers and steam hammers) were developed and were used to power various mechanical actions (Gannon 2014). After 1900, factories were electrified and electric motors and controls were used to perform mechanical operations which were more complicated (David 1990). The step beyond mechanization is automation, which becomes popular in 1940s worldwide (Robinson 2014). Automation mainly refers to the use of various control systems for operating equipment with minimal or reduced human intervention (Kapliński et al. 2002). It is normally achieved by various means including mechanical, hydraulic, pneumatic, electrical, electronic and computers, usually in combination. Automation can bring substantial benefits. It can lead to a leaner operation process that requires less energy and material consumption. It can also produce improvements in quality, accuracy and precision (Bock 2015; Robinson 2014).