Helena M. Ramos

• Professor
• Full Professor at University of Lisbon

Integrating renewable energy sources into the power system is essential for rapid and cost-effective decarbonization. This study evaluates the potential of a wind farm by analyzing three turbine models – VESTAS, GAMESA, and W2E – with power capacities from 2.5 MW to 8 MW. The analysis focuses on Region III, characterized by wind speeds below 7.5 m/...

This study explores the advantages of combining variable renewable energy sources like solar and wind with a pumped storage hydroelectric (PSH) system for grid integration. The hybrid modeling systems considered in this study consist of four distinct schemes and seasons to ensure their adaptability to real-world conditions. Each scheme is defined b...

The calculation of peak discharge in non-instrumented basins requires including morphometric parameters, which in turn depend on the map type used. This study analyses the impact of and variation in peak discharges of the Caño Ricaurte basin, Colombia, based on three types of maps at different resolution scales. The reference map used was the map m...

: There has been an ever-increasing demand for energy from the past decades. Renewable energy technologies play a major role in satisfying the energy demand as well as in a decreased CO2 emissions. Solar and Wind energies are the major upcoming technologies in renewable energies. Decentralized power production is a system where the energy productio...

During the Digital Decade, the European Union (EU) is facing two important challenges: the green (and energy) transition and the digital transition, which are interconnected with one another. These transitions are of high relevance in several aspects of our life, e.g., in the industry, energy sector, transports, environmental management and our dai...

The outlet angle and shape of impeller blades are important parameters in centrifugal pump design. There is a lack of detailed studies related to double curvature impellers in centrifugal pumps in the current literature; therefore, an experimental and numerical analysis of double curvature impellers was performed. Six impellers were made and then a...

In hydraulic engineering, some researchers have developed different mathematical and numerical tools for a better understanding of the physical interaction between water flow in pipes with trapped air during emptying processes, where they have made contributions on the use of simple and complex models in different application cases. In this article...

The calculation of base flow rates in rivers is complex since hydrogeological and hydrological studies should be performed. The estimation of base flow rates in storm hydrograph associated to various return periods is even more challenging compared to other events. This research provides a novel methodology to compute base flow rates in gaged river...

Addressing climate change and energy crises is considered one of the world's greatest energy challenges. The presence of proven and reliable energy storage is fundamental to addressing climate change, which is needed to support intermittent renewable energy for a rapid transition of the energy sector from conventional fossil fuels to decarbonized e...

This research aims to evaluate and put into practise the design of a small hydropower plant on a stream at São Vicente, in Madeira Island, supported by internet of things (IoT). The photogrammetry technique is also used with a comprehensive digital transformation, in which new concepts, methods and models, such as machine learning (ML), and big dat...

Over the past few years, there has been significant interest in the importance of reversible hydro-pumping systems due to their favorable flexibility and economic and environmental characteristics. When designing reversible lines, it is crucial to consider dynamic effects and corresponding extreme pressures that may occur during normal and emergenc...

This study examines the impact of sub-atmospheric pressures in water pipelines during emptying manoeuvres with air admitted. Previous research has looked at this issue but has not studied it in detail. This research presents a two-dimensional model using the OpenFOAM software to analyse different emptying manoeuvres in a single pipeline with entrap...

The estimation of thermodynamic behavior during filling processes with entrapped air in water pipelines is a complex task as it requires solving a system of algebraic-differential equations. A lot of different numerical methods have been used for this purpose in literature including the rigid water column (RWC) model. The main advantage of the RWC...

Urbanization and population growth have been responsible for a significant increase in consumption of water and energy at a global scale. A careful management of water resource and infrastructures is crucial for Energy Transition, as well as for achieving a sustainable efficiency of these systems. High pressure values along with the ageing of the s...

One of the main factors contributing to water scarcity is water loss in water distribution systems, which mainly arises from a lack of adequate knowledge in the design process, optimization of water availability, and poor maintenance/management of the system. Thus, from the perspective of sustainable and integrated management of water resources, it...

The use of these new interaction tool implies the improvement of the awareness of the whole system and it lies in improving the sustainability and efficiency of the water systems with the integration of measurements. The research proposed a methodology, which enables improvement in the accuracy and reliability of data and it increases the performan...

Water conveyance systems are notorious for incurring considerable energy expenditures, either as losses of gravitational potential energy or as increased electricity consumption. Entrapped air pockets, originating from ineffective or nonexistent air management schemes, are common and often significant contributors to these energy costs. This work s...

A filling operation generates continuous changes over the shape of an air–water interface, which can be captured using a 3D CFD model. This research analyses the influence of different hydro-pneumatic tank pressures and air pocket sizes as initial conditions for studying rapid filling operations in a 7.6 m long PVC pipeline with an irregular profil...

This research proposes a methodology with multi-objective optimization for the placement of Pumps operating As Turbines (PATs), energizing street lighting, devices for monitoring the water network, and charging stations for small electric vehicles such as bikes and scooters. This methodology helps to find the most profitable project for benefiting...

The open source and freely available fluid flow solver named caffa3d was adapted to simulate the performance of a medium-scale Hydrostatic Pressure Machine (HPM) with straight radial blades, which had been previously tested in a laboratory facility. A fully detailed explanation of the code caffa3d is not intended to be included in this paper, but s...

Air valves operate as protection devices in pipelines during drainage processes in order to mitigate vacuum pressures and control the transient flows. Currently, different authors have proposed one-dimensional models to predict the behaviour of orifices during filling and draining events, which offer good numerical results. However, the three-dimen...

Micro hydropower (MHP) provides a viable renewable energy solution from which individuals, organisations and communities can also derive social value and benefits. Desk studies and literature reviews show limited studies that (a) quantify the social impact of MHPs in water networks and (b), establish evaluation methods for such analysis. To date, m...

The risks associated with unsteady two-phase flows in pressurized pipe systems must be considered both in system design and operation. To this end, this paper summarizes experimental tests and numerical analyses that highlight key aspects of unsteady two-phase flows in water pipelines. The essential dynamics of air–water interactions in unvented li...

Air is present in pressurized water systems for a variety of reasons, including incomplete removal during filling, air entrainment at intakes or entrances, air admission during draining operations, or air exchanges due to transient events such as power failure or pipe burst. Each of these sources or events creates specific design and operational ch...

A review of different energy components is detailed, as a baseline of fundamentals for the new integrated energy concept idealization. This innovative solution is a Hybrid for Renewable Energy Network (Hy4REN) based on well-studied elements to produce the best final solution. This proposal has the objective of improving energy system sustainability...

Hydraulic turbines for energy recovery in wastewater treatment plants, with relatively large discharges values and small head jumps, are usually screw Archimedes or Kaplan types. In the specific case of a small head jump (about 3 m) underlying a rectangular weir in the major Palermo (Italy) water treatment plant, a traditional Kaplan solution is co...

The recovery of excess energy in water supply networks has been a topic of paramount importance in recent literature. In pressurized systems, a pump used in inverse mode (Pump As Turbine, PAT) demonstrated to be a very economical and reliable solution, compared to traditional energy production devices (EPDs). Due to the large variability of flow ra...

Nowadays, in the management of water distribution networks (WDNs), particular attention is paid to digital transition and the improvement of the energy efficiency of these systems. New technologies have been developed in the recent years and their implementation can be crucial to achieve a sustainable level of water networks, namely, in water and e...

The sizing of air valves during the air expulsion phase in rapid filling processes is crucial for design purposes. Mathematical models have been developed to simulate the behaviour of air valves during filling processes for air expulsion, utilising 1D and 2D schemes. These transient events involve the presence of two fluids with different propertie...

Water distribution networks have high values of energy consumption from the source to the distribution. The use of pumps working as turbines is an innovative technology for leverage the energy excess in consumption nodes. The research proposes a new methodology, which couples the energy generation with other energy-consumption systems. The main goa...

The use of pump working as turbine (PAT) instead of the traditional pressure regulation systems could allow for a recovery of the excess hydraulic energy to reduce the energy footprint of the water supply industry and at the same time control the water losses by an effective reduction in pressure induced by the turbine head drop. This research aims...

Water distribution networks need to improve system efficiency. Hydropower is a clean and renewable energy that has been among the key solutions to environmental issues for many decades. As the turbine is the core of hydropower plants, high attention is paid to creating new design solutions and increasing the performance of turbines in order to enha...

Urban drainage systems are in transition from functioning simply as a transport system to becoming an important element of urban flood protection measures providing considerable influence on urban infrastructure sustainability. Rapid urbanization combined with the implications of climate change is one of the major emerging challenges. The increased...

To listen-see this webinar please use this link: https://water-4.sciforum.net/ The complete webinar was recorded and published online in Youtube channel.

The use of pumps working as turbines (PATs) is a sustainable technical measure that contributes to the improvement of energy efficiency in water systems. However, its performance analysis in off-grid recovery systems is a complex task that must consider both hydraulic (PAT) and electrical machines (typically a self-excited induction generator-SEIG). A...

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Chlorine demand as a disinfectant for water utility impacts on unintended energy consumption from electrolysis manufacture; thus, diminishing the chlorine consumption also reduces the environmental impact and energy consumption. Problems of disinfectant distribution and uniformity in Water Distribution Networks (WDN) are associated with the exponen...

Most renewable energy (RE) studies focus on technology readiness, environmental benefits and/or cost savings. The market permeation, viability and adoption of RE technologies such as micro hydropower (MHP), however, require the alignment of other interrelated factors, such as the socio-technical, institutional and political dimensions. This is part...

Water management and energy recovery can improve a system’s sustainability and efficiency in a cost-effective solution. This research assesses the renewable energy sources used in the water sector, as well as the related water sector performance indicators within Portuguese water management systems. A deep analysis of 432 water entities in Portugal...

Sustainability and efficiency in irrigation are essential in the management of the water–energy–food nexus to reach the Sustainable Development Goals in 2030. In irrigation systems, the reduction of energy consumption is required to improve the system efficiency and consequently the sustainability indicators of the water network. The use of pumps w...

Studies have shown micro-hydropower (MHP) opportunities for energy recovery and CO2 reductions in the water sector. This paper conducts a large-scale assessment of this potential using a dataset amassed across six EU countries (Ireland, Northern Ireland, Scotland, Wales, Spain, and Portugal) for the drinking water, irrigation, and wastewater sector...

p>Os sistemas de abastecimento, distribuição e drenagem do setor da água são um dos principais tipos de sistemas hidráulicos artificiais com potencial para a instalação de micro-hídricas. Apesar de existirem algumas aplicações de mini-hidroeletricidade nas condutas de adução, as redes de distribuição de águas urbanas e de rega continuam a ser pouco...

Current and future smart cities are moving towards the zero-net energy use concept. To this end, the built environment should also be designed for efficient energy use and play a significant role in the production of such energy. At present, this is achieved by focusing on energy demand in buildings and to the renewable trade-off related to smart p...

Environmental hydraulics research includes the different domains of hydrodynamics, such as the investigation and implementation of the physical and experimental applications, and research into the quantity, quality, modelling and simulation of the attributes associated with flowing water. This topic is studied both from a technical and environmenta...

A elevada intermitência das fontes de energia renováveis condiciona a produção de energia elétrica, que continua a depender muito dos combustíveis fósseis. Uma vez que existe complementaridade por parte das fontes de energia renováveis, a sua integração conjunta é, sem dúvida, a melhor solução para reduzir esta dependência. Aliado a este facto, pod...

The use of pumps working as turbines (PATs) is a sustainable technical measure that contributes to the improvement of energy efficiency in water systems. However, its performance analysis in off-grid recovery systems is a complex task that must consider both hydraulic (PAT) and electrical machines (typically a self-excited induction generator-SEIG)...

This study presents a technique based on a multi-criteria evaluation, for a sustainable technical solution based on renewable sources integration. It explores the combined production of hydro, solar and wind, for the best challenge of energy storage flexibility, reliability and sustainability. Mathematical simulations of hybrid solutions are develo...

The Hydrostatic Pressure Machine (HPM) is a novel energy converter for micro and pico hydropower that becomes very suitable for installation in channels with very low head, where conventional hydraulic turbines are inadequate or too expensive. Although this technology has been studied through several experimental tests and also by numerical simulat...

New challenges in water systems include different approaches from analysis of failures and risk assessment to system efficiency improvements and new innovative designs. In water distribution networks (WDNs), the risk function is a measure of its vulnerability level and security loss. Analyses of transient flows which are associated with the most da...

Energy and climate change are thoroughly linked since fossil energy generation highly affects the environment, and climate change influences the renewable energy generation capacity. Hence, this study gives a new contribution to the energy generation in water infrastructures by means of an inline pumped-storage hydro (IPSH) solution. The selection...

The capability of two different OpenFOAM® solvers, namely interFoam and twoPhaseEulerFoam, in reproducing the behavior of a free water jet was investigated. Numerical simulations were performed in order to obtain the velocity and air concentration profiles along the jet. The turbulence intensity was also analyzed. The obtained results were compared...

A crescente crise energética e o consumo excessivo de recursos levantam a preocupação de encontrar novas fontes alternativas de energia, viabilizando novos métodos de produção e/ou tornando mais eficientes os que já existem. Pretende-se investigar a viabilidade do aproveitamento de energia em excesso em sistemas de abastecimento de água, de drenage...

The optimal and sustainable management of water distribution systems still represent an arduous task. In many instances, especially in aging water net-works, pressure management is imperative for reducing breakages and leakages. Therefore, optimal District Metered Areas represent an effective solution to decreasing the overall energy input without...

In recent years, interest has increased in new renewable energy solutions for climate change mitigation and increasing the efficiency and sustainability of water systems. Hydropower still has the biggest share due to its compatibility, reliability and flexibility. This study presents one such technology recently examined at Instituto Superior Técni...

The use of pumps working as turbines (PATs) to improve the energy efficiency of water networks has been studied in the last years. This recovery system is justified due to a low investment contrasting with the capacity to take advantage in certain points with low and medium recoverable heads. Analyses of water systems using simulation software and/...

Water supply systems are one of the main hydraulic systems with significant potential for installation of micro-hydropower solutions. Although there are already some mini-hydropower applications in the water sector, there is still a huge potential that continue to be under-exploited. Micro-hydro systems can be used as promising new source of renewa...

Water management towards smart cities is an issue increasingly appreciated under financial and environmental sustainability focus in any water sector. The main objective of this research is to disclose the technological breakthroughs associated with water and energy use. A methodology is proposed and applied in a case study to analyze the benefits...

The filling process in water pipelines produces pressure surges caused by the compression of air pockets. In this sense, air valves should be appropriately designed to expel sufficient air to avoid pipeline failure. Recent studies concerning filling maneuvers have been addressed without considering the behavior of air valves. This work shows a math...

Water distribution networks and irrigation systems consume high energy quantities that need to be recovered if the water managers want to meet sustainable systems. A sustainability optimization is proposed in this research in order to replace the energy consumption in a golf-course system by renewable solutions joining energy recovery, sustainable...

The occurrence of sub-atmospheric pressure in the drainage of pipelines containing an air pocket has been known as a major cause of several serious problems. Accordingly, some system malfunction and pipe buckling events have been reported in the literature. This case has been studied experimentally and numerically in the current research considerin...

Water supply systems are one of the main hydraulic systems with significant potential for the installation of micro-hydropower devices. Although there are already some mini-hydropower applications in water supply systems, it is still a huge potential that continues to be under-exploited. The arrangement based on an axial turbine, such as an inline...

The rapid deployment of renewable energy technologies continues, yet the environmental impacts associated with their construction is accepted without sustainable design considerations. This life cycle assessment study quantifies the embodied burdens in the construction phase of eleven micro-hydropower installations, ranging from 70–100 kW in size....

Pumps as Turbines (PATs) are standard water pumps utilized as hydraulic turbines by reversing the flow direction across them. The off-the-shelf availability of water pumps and their reduced purchase price with respect to conventional hydro turbines makes them an ideal technology for exploiting large portions of uncapped hydro potential that is tech...

Micro-hydro systems can be used as a promising new source of renewable energy generation, requiring a low investment cost of hydraulic, mechanical, and electrical equipment. The improvement of the water management associated with the use of pumps working as turbines (PATs) is a real advantage when the availability of these machines is considered fo...

Inconsistences regarding flow measurements in real hydraulic circuits have been detected. Intensive studies stated that these errors are mostly associated to flowmeters, and the low accuracy is connected to the perturbations induced by the system layout. In order to verify the source of this problem, and assess the hypotheses drawn by operator expe...

The estimation of unsteady parameters in two-phase condition is crucial for the safety and reliability of the hydraulic systems. There are plenty of one-dimensional (1D) simulation tools for unsteady flow estimation being some of them able to present good results in monophasic flows, while almost all of them are not suitable for two-phase flows. In...

Filling and emptying operations should be planned by engineers in operational stages to prevent a system failure depending on reaching extreme low pressure values. In this sense, a compression of an air pocket produces pressure surges, while an expansion generates troughs of subatmospheric pressure. A sensitivity analysis of main hydraulic and ther...

The prediction of the pressure inside the air pocket in water pipelines has been the topic for a lot of research works. Several aspects in this field have been discussed, such as the filling and the emptying procedures. The emptying process can affect the safety and the efficiency of water systems. Current research presents an analysis of the empty...

REDAWN project will foster the adoption of hydropower energy recovery technology in built water networks in the Atlantic Area (AA). REDAWN will develop an adequate institutional, social and technological environment to foster greater resource efficiency in water networks. Pumps working as turbines (PAT) and other converters (wheels) became attracti...

PATs are a viable and low-cost solution suitable for implementation in water networks. The basic economic parameters, the time value of money, methods of economic evaluation and the effects of the lifetime cycle are presented. The determination of analytical formulas to predict the PAT purchase price is shown. The installation of a PAT as a replace...

Users, researchers and engineers require a fundamental knowledge of reverse pump theory. In this chapter first, a complete description of all PAT components is given. Then, the theory of small reverse pumps is described, based on the results of theoretical analyses, experiments and numerical simulations. PAT characteristic and efficiency curves are...

The main rules for the selection of the regulation mode of a PAT based on the operating conditions are presented, as measured at the point of the network where the power plant will be located. The variability of operating conditions in water supply networks is discussed and the influence of the daily demand variation of the flow rate and available...

A number of existing hydropower plants are described, which have a power generation capacity ranging between a few kW and a hundred kW, thus proving the extreme flexibility of PAT technology. Several different designs are shown, with the best solution depending on the power plant data and on the problem constraints. In addition, the layout of some...

A PAT normally has a lower efficiency than a conventional turbine applied at the same site. In the long term, a higher efficiency is important for users in that more energy is produced. A pump’s geometry can be modified to improve its efficiency in turbine mode. Several methods of PAT geometry modification are presented for the improvement of PAT e...

The importance of pressure control in water transmission systems with the identification of flow energy dissipation points is presented. The numerical methods used to analyze the behavior of the hydraulic system, the control valve maneuvers, and the over-speed effect associated with the dynamic behavior of the PAT are discussed. The dynamic control...

Information about the different components of a PAT and an overall description of civil engineering design are presented. The electromechanical transmission arrangements realized to avoid dissipative effects and to guarantee the best operating conditions are defined and additional aspects associated with installation procedures and operation and ma...

A simple methodology for PAT selection starting from the performance of the pump in direct mode is given, based on a number of studies on PAT behavior present in expert literature. The expected errors in terms of head and PAT efficiency between the results of this methodology and the experimental data are also discussed, and the possibility of intr...