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The removal of water from mines was one of the key issues that former miners had to deal with. Roman colonists brought new technology to the Iberian Peninsula that addressed this problem. However, they did not invent this technology because it had already been applied to the growth of other endeavours in the Hellenistic society throughout the Eastern Mediterranean. In the mine, the Archimedes screw, waterwheels, bucket pulleys, and Ctesibius pumps were the primary drainage systems. In this essay, the primary characteristics, and modes of operation of machines are examined. Without leaving out the most significant finds made in the southwest of the Iberian Peninsula, one of the regions with the longest history of mining exploitation. To serve as a foundation for future research in this field, this work compares the primary mining mechanisms in ancient Huelva on a qualitative and quantitative level by the implementation of a TOPSIS methodology, a multi-criteria decision analysis method. [ABSTRACT FROM AUTHOR]

For hundreds of years, water mills have supported the local economies of Piedmont by contributing to the production of flour, textile fibres, timber, and metal agricultural tools. Since the beginning of the last century, and in particular after the 1950s, many artefacts have been abandoned. Nonetheless, hundreds of mills are still present in southern Piedmont, both in the plains and in the mountains, sometimes in an excellent state of conservation. This work presents a hammer forge, the La Pianca mill in Busca, Cuneo, Italy, as a significant, detailed case study. The socio-economic context in which exists is analysed, its history is reconstructed, and the functioning of the machinery, including the water wheels, the motion transmission systems, and the various utilities consisting of tilt hammers, grinding wheels, and drills, is analysed in detail. Beyond the historical interest, concerning both the territory and the architecture, as well as the machines and mechanisms, this work aims to make a contribution to the prefiguration of effective scenarios for the reconversion of similar productive artefacts. [ABSTRACT FROM AUTHOR]

The world is increasingly shifting toward low-head hydropower as a sustainable form of renewable energy in response to the negative socioeconomic impacts of large hydroelectric plants. In this context, the article presents a novel design involving retrofitting the gates of existing dam structures with Dethridge waterwheel technology. This innovative solution installs the wheel under the gate to harvest the untapped potential energy resulting from the head difference at these already-existing facilities while simultaneously reducing the need for costly civil work and preventing new installations in freshwater systems. The El-Reah El-Tawfiqy barrage in Egypt served as the model case study for evaluating the implementation of the proposed design. According to the results, the plant's levelized cost is 29 USD/MWh, less expensive than traditional hydropower projects and achieves grid parity. With an estimated 140 MWh of electricity produced annually, the project is expected to cut around 1460 tons of CO 2 equivalent over its 25-year lifespan. This study includes several novelties, including modifying hydraulic structure gates for pico power generation. Additionally, a thorough numerical analysis was performed to estimate the output power instead of relying on theoretical approaches for the economic viability study. These results can guide policymakers and stakeholders in implementing affordable and sustainable renewable energy solutions. [Display omitted] [ABSTRACT FROM AUTHOR]

Water wheels used for power generation are applied to tailwater and ultra-low head sites. In this research, the VOF method and the standard k-ε turbulence model are utilized to predict the performance and transient flow fields of water wheels. The numerical results show a reasonable agreement with the experimental data. This work aims at improving the performance and increasing the internal fluid stability of the water wheel, based on the entropy production approach to research the detailed distribution of energy loss in the water wheel for power generation under the clearance effects between blades and hub. Under the same rotational speed, it is indicated that by setting appropriate clearance, the performance of the water wheel can be elevated by 8.7%, targeted elimination of vortical flow, improving flow adaptability, attenuating to a great extent of the backwater phenomenon, and reducing the fatigue damage of the hub and blade. Further, the interaction mechanism of vorticity–pressure which will induce irreversible energy loss of the water wheel under different clearance effects is investigated. Therefore, this research indicates that the entropy method can provide a theoretical reference and engineering guidance for the targeted optimization of water wheels. [ABSTRACT FROM AUTHOR]

Roman mines faced numerous problems that caused work to be discontinued and sites abandoned. One such problem is groundwater resulting from digging near rivers or sees or leakages from the top of the mine. The Romans initially tackled this problem using the primitive means – current since the earliest times – of digging canals to redirect the flow of groundwater and then raising it using buckets and ropes. Later they introduced mechanical machines like Archimedes’ screw, which they soon replaced with the more modern waterwheel. An Alexandrian invention dating from the Ptolemaic era, the waterwheel had spread across the Mediterranean where it was used for agricultural work until the Roman era when its design was developed for use in a variety of fields including mining. Hundreds of waterwheels were used to lift water out of Roman mines.This paper raises a number of questions regarding how the waterwheel was used in mines, how giant machinery was transported into the mine, what was the mechanism for operating them once they were inside, were they similar to agricultural waterwheels (which relied on either water pressure or human and/or animal power), and when and why the Romans started using them.In the absence of primary sources dealing with the topic, research relies on various theories proposed following excavations in which mines were discovered at various points in history. The writer outlines the history of these discoveries and undertakes a comparative study of the theories proposed in order to reach the most plausible explanation. The paper follows the following scheme:1-Introducing and describing the waterwheel as defined by the Roman engineer Vitruvius;2-Surveying the discoveries and presenting the theories that were proposed at the time they were made over the centuries; and3-Surveying modern discoveries and comparing them to older ones.

A large-scale two-dimensional computational fluid dynamics study is conducted in order to maximise the power output and smoothness of power delivery of a free-stream water wheel, a low-impact hydropower device. Based on models and methods developed in previous research, the study uses a genetic algorithm to optimise the geometry of a wheel with a given radius and depth, maximising two objective functions simultaneously. After convergence and suitable post-processing, a single optimal design is identified, featuring eight shortened blades that become fully immersed at the nadir point. The design results in a 71% reduction in blade material and a 113% increase in the work ratio while improving the hydraulic power by 8% compared to the previous best design. These characteristics are applied retroactively to a broad family of designs, resulting in significant improvements in performance. Analysis of the resulting designs indicates that when either the hydraulic power coefficient, rotor power coefficient, or work ratio is considered, free-stream water wheels with fully immersed blades, whose power mechanisms are shown to rely on lift, as well as drag, outperform all other designs studied so far. [ABSTRACT FROM AUTHOR]

Small hydropower plants (installed power below 10 MW) are generally considered less impacting than larger plants, and this has stimulated their rapid spread, with a developing potential that is not exhausted yet. However, since they can cause environmental impacts, especially in case of cascade installations, there is the need to operate them in a more sustainable way, e.g. considering ecosystem needs and by developing low-impacting technologies. In this paper, an assessment was conducted to estimate how the environmental flow and the plant spatial density affect the small hydropower potential (considering run-of-river schemes, diversion type, DROR) in the European Union. The potential of DROR is 79 TWh/y under the strictest environmental constraints considered, and 1,710 TWh/y under the laxest constraints. The potential of low-impacting micro technologies (< 100 kW) was also assessed, showing that the economic potential of hydrokinetic turbines in rivers is 1.2 TWh/y, that of water wheels in old mills is 1.6 TWh/y, and the hydropower potential of water and wastewater networks is 3.1 TWh/y, at an average investment cost of 5,000 €/kW. [ABSTRACT FROM AUTHOR]

For hundreds of years, water mills have supported the local economies of Piedmont by contributing to the production of flour, textile fibres, timber, and metal agricultural tools. Since the beginning of the last century, and in particular after the 1950s, many artefacts have been abandoned. Nonetheless, hundreds of mills are still present in southern Piedmont, both in the plains and in the mountains, sometimes in an excellent state of conservation. This work presents a hammer forge, the La Pianca mill in Busca, Cuneo, Italy, as a significant, detailed case study. The socio-economic context in which exists is analysed, its history is reconstructed, and the functioning of the machinery, including the water wheels, the motion transmission systems, and the various utilities consisting of tilt hammers, grinding wheels, and drills, is analysed in detail. Beyond the historical interest, concerning both the territory and the architecture, as well as the machines and mechanisms, this work aims to make a contribution to the prefiguration of effective scenarios for the reconversion of similar productive artefacts.

The performance of controlled hybrid renewable hydro matrix wheels/ wind in micro grid application during the variations of water speed and load is described and investigated. This hybrid contained three wheels and three wind turbines modeled in MATLAB Simulink. This presented hybrid model consists of a water wheel and a generator in the main channel, wind turbine drives an induction generator, battery, variable static load, DC link, and control unit. Appropriate controllers are used to maintain the DC-link voltage constant at its desired value with variations of load, water and wind speed. The obtained simulated result shows that the studied hybrid system with the proposed controller and the storage system have a better performance of load voltage and current waveform compared with the case of not using an energy storage unit and the case of without a controller under the water, wind speed and load variations.

The development of a low-power (1–10 kW) hydraulic motor for mobile micropower stations and pumps is considered; it is based on the energy of water moving under gravity in a river or other water body. A prototype motor is tested. [ABSTRACT FROM AUTHOR]

A new type of wave power generation system was proposed by using bending plate type generator installed in a vertical slit type breakwater. The system has some advantage compared with other systems; namely, (i) no occupation of the sea surface, (ii) maintenance facility, and (iii) high energy efficiency by using accelerated flow from the slit of breakwater. The generator has a quite simple structure composed of a rectangular plate or cloth connected to a wheel and axle via a string set in the water chamber. When the wave drag bends the plate or cloth, a tension appears in the string and it rotates the wheel connected to a generator. In this report, the maximum output obtained in 1/12 scale model experiment was examined by changing the size of the bending plate. In addition, we also examined the float type power generation mechanism using the water level change in the water chamber and evaluated the output when combined with the bending plate. The experimental results showed that the output of the proposed system per unit sea area is superior to those of the other types of generators

In this study, the internal structure of a Heumgyeonggak-nu (欽敬閣漏) was designed, and the power transmission mechanism was analyzed. Heumgyeonggak-nu is an automated water clock from the Joseon Dynasty that was installed within Heumgyeonggak (欽敬閣), and it was manufactured in the 20th year of the reign of King Sejong (1438). As descriptions of Heumgyeonggak-nu in ancient literature have mostly focused on its external shape, the study of its internal mechanism has been difficult. A detailed analysis of the literature record on Heumgyeonggak-nu (e.g., The Annals of the Joseon Dynasty) indicates that Heumgyeonggaknu had a three-stage water clock, included a waterfall or tilting vessel (欹器) using the overflowed water, and displayed the time using a ball. In this study, the Cheonhyeong apparatus, water wheel, scoop, and various mechanism wheels were designed so that 16 fixed-type scoops could operate at a constant speed for the water wheel with a diameter of 100 cm. As the scoop can contain 1.25 l of water and the water wheel rotates 61 times a day, a total of 1,220 l of water is required. Also, the power gear wheel was designed as a 366-tooth gear, which supported the operation of the time signal gear wheel. To implement the movement of stars on the celestial sphere, the rotation ratio of the celestial gear wheel to the diurnal motion gear ring was set to 366:365. In addition, to operate the sun movement apparatus on the ecliptic, a gear device was installed on the South Pole axis. It is expected that the results of this study can be used for the manufacture and restoration of the operation model of Heumgyeonggak-nu.

Abstract Utilizing the kinetic energy of a flowing river for irrigation could be tracked back to Hellenistic and Roman periods. In modern days, hydroelectric plants are built for harvesting the kinetic energy of the flowing river. However, a large investment is required in the hydroelectric plants for maximizing the power output. Here we present a low-cost and scalable TENG (triboelectric nanogenerators) based energy harvesting water wheel (ww-TENG). The water wheel works in a sliding freestanding TENG mode which generates power from the charges flow induced by contact electrification and electrostatic induction. A conformal fluorine coated carbon paper (f-CP) was employed to form the alternate electrodes. The deposited fluorine layer provides the benefits of high affinity to attract electrons as well as hydrophobicity for water repelling. The carbon paper offers a high electrical conductivity and rough structure to form a superhydrophobic property. These features enables a large charge induction and fast water/TENG separation for maximizing the power output of the energy harvesting water wheel. A lab-scale water wheel (diameter 10 cm and width 2.5 cm) is fabricated and a maximum 5.3 μW output power was measured under 50 MΩ resistance at a linear flow velocity of 2.6 m/s. The ww-TENG was employed for charging a 10 μF capacitor to 16 V and lighting up a commercial LED light bulb. As a comparison, an electromagnetic generator (EMG) could only charge the capacitor to 2.7 V with the same period of time. The EMG obtains a high power output at low load resistance case (< 100 kΩ) while the ww-TENG generates high power when the load resistance is large (> 10 MΩ). The present ww-TENG shows great potential for harvesting the kinetic energy from flowing river and targets for the applications with large load resistance like electrostatic systems. Graphical abstract A sliding freestanding mode TENG based energy harvesting water wheel is presented with a fluorine coated carbon paper electrode. fx1 Highlights • A sliding freestanding mode TENG based energy harvesting water wheel is proposed. • Fluorine coated carbon paper enables fast separation between water and TENG. • The proposed ww-TENG could be used to light up a commercial LED bulb. [ABSTRACT FROM AUTHOR]

Heumgyeonggaknu (欽敬閣漏) is powered by a water-hammering-type water wheel. The technique that maintains the constant speed of the water wheel is assumed to be the one used in the Cheonhyeong (天衡) apparatus in Shui Yun Yi Xiang Tai (水運儀象臺) made by the Northern Song (北宋) dynasty in the 11th century. We investigated the history of the development and characteristics of the Cheonhyeong apparatus, and we analyzed ways to transmit the power of Heumgyeonggaknu. In addition, we carried out a conceptual design to systematically examine the power control system. Based on the conceptual design, we built a model for a water wheel control system that could be used in experiments by drawing a 3D model and a basic design.

Abstract Nowadays, due to the need for clean energy and sustainable electricity production, hydropower plays a central role in satisfying the energy demand. Particularly, use of low head micro hydropower plants is spreading worldwide, due to their low payback periods and good environmental sustainability. Gravity water wheels are micro hydropower converters typically used in sites with heads less than 6 m and discharges of a few cubic meters per second. Although water wheels were scientifically investigated as far back as the eighteenth century, they were largely ignored throughout the twentieth century, and only in the last two decades has there been a renewed interest in their use among the scientific community. In this paper a review on gravity water wheels is presented, distinguishing between undershot, breastshot and overshot water wheels. Water wheels technology is discussed focusing on geometric and hydraulic design; data and engineering equations found in historic books of the nineteenth century are also presented. Water wheels' performance is described examining experimental results, and modern theoretical models for efficiency estimation are presented. Finally, results achieved through experiments and numerical simulations were discussed with the aim of optimizing the performance of gravity water wheels. The results showed that maximum efficiency of overshot and undershot water wheels was around 85%, while that of breastshot water wheels ranged from 75% to 80%, depending on inflow configuration. Maximum efficiency of modern water wheels can be maintained at such high values over a wider range of flow rates and hydraulic conditions with respect to older installations. Hence well designed water wheels can be considered as efficient and cost-effective micro hydropower converters. Highlights • Water wheels are cost-effective hydropower converters, especially in rural areas. • Water wheels are low head hydropower machines with 85% maximum efficiency. • Modern results should be used for their design to support old empirical equations. • Their performance can be optimized and their operation made more flexible. [ABSTRACT FROM AUTHOR]

In this paper, an analysis of the performance and flow fields of water wheel turbines for tidal energy extraction is carried out using experimental and numerical methods. The purpose of this work is to develop a water turbine suitable for sites, where fast and shallow surface flows are available, such as rivers or tidal currents. For both methods, the water wheel turbine is tested over a range of tip speed ratios with a differing number of rotor blades, ranging between three and twelve. The results indicate that the numerical simulation shows agreement with the experiment in most cases. Also, the water wheel turbine operates effectively at a range of small tip-speed ratios, where the highest turbine efficiency is produced. Under the same working conditions, the turbines using between six and nine blades generate a greater efficiency and cause lesser reverse flows than others when submerged in water. In contrast, the 3-bladed turbine is the least efficient design as it produces the lowest amount of energy and causes intense vibrations and noises. These noises are a result of a collision between the incoming flow of the channel and the wheel blades during the experimentation, especially at high load conditions. By adding more blades, the torque generated is improved considerably; however, the upstream and downstream depths of the turbine, in this case, are also elevated significantly. Furthermore, in the inlet region, the 3-bladed and 6-bladed turbines have a smaller shock loss and a lower resistance to the main flow from the inlet than the others. Meanwhile, it is found that the flow in the outlet region on the turbines with between nine and twelve blades is in the opposite direction to the wheel's rotation, significantly obstructing the main flow from the inlet. [ABSTRACT FROM AUTHOR]

Since ancient times and for hundreds of years, grain mills, hammers, sawmills, spinning mills, and hemp rollers have been powered by water wheels. In the nineteenth century there were hundreds of thousands of mills in all of Europe. It is an enormous historical and cultural heritage of inestimable value, which is for the most part, abandoned today. Recently, there is a renewed interest in their reuse, both for their widespread diffusion in the territory and for the excellent environmental integration and intrinsic sustainability. Even when, for economic reasons, their recovery for the original tasks is not suitable, the conversion into mini plants for the production of electricity can be advantageous. In the paper, analyzing some typical examples of the old water mill of the Piemonte region, in North-West of Italy, the mechanical architecture of old water mill, from water wheels to millstones, is described and the functional details of various mechanisms are provided. In fact, by knowing only the specifics of the ancient mills, it is possible to enhance their potential and restore them from the perspective of a renewed high quality production, or reconvert them in mini-plants for the production of electricity.

Water wheels can be efficient hydropower converters at low heads and low discharges. The paper presents the results of a study of a breastshot water wheel in a laboratory experimental channel. The obtained data show that breastshot water wheels can reach a maximum efficiency of about 75%, at a rotational velocity which is about 60% of the runaway velocity. The maximum efficiency is constant over a wide range of flow rates. A dimensional analysis is then carried out and a simple relationship for estimating the maximum mechanical power output of geometrically similar wheels is determined, relating the Newton number (dimensionless maximum power output) to the Reynolds number (function of the hydraulic conditions and channel geometry). [ABSTRACT FROM AUTHOR]