Direct and Indirect Water Supply: An Energy Assessment

Gómez, Elena; Cabrera, Enrique; Balaguer, M.; Soriano, Javier

doi:10.1016/j.proeng.2015.08.941

Cited by 21 publications

(18 citation statements)

References 6 publications

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“…In fact, direct pumping becomes advantageous as long as the pumping head can be reduced, and its convenience increases as such a reduction increases. A similar behavior can be observed by the analysis of the efficiency indices proposed by Gómez et al [34] and Cabrera et al [35].…”

Section: Discussionsupporting

confidence: 84%

“…Moreover, in Table 2, "direct scenario cutoff" represents the value of Δ until which direct pumping is the most convenient scenario. [34,35] introduced some efficiency indices of ideal (η ai ) and real (η ar ) systems. These indices are presented in Equations (17) and (18).…”

Section: Energy Indices Under Differing Boundary Conditionsmentioning

confidence: 99%

“…The authors of [34,35] defined these indices to give an overview of the energy efficiency of the supply system and the whole distribution. Applying these to the current case study, for the indirect pumping scenario, η ai is equal to 0.37, whereas η ar is equal to 0.24 with energy recovery (η ar,1.2 ) and 0.22 otherwise (η ar,1.2 ).…”

Section: Energy Indices Under Differing Boundary Conditionsmentioning

confidence: 99%

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A Comparison of Energy Recovery by PATs against Direct Variable Speed Pumping in Water Distribution Networks

Morani

Carravetta

Giudice

et al. 2018

Fluids

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Water systems are usually considered low efficiency systems, due to the large amount of energy that is lost by water leakage and dissipated by pressure reducing valves to control the leakage itself. In water distribution networks, water is often pumped from the source to an elevated tank or reservoir and then supplied to the users. A large energy recovery can be realized by the installation of energy production devices (EPDs) to exploit the excess of pressure that would be dissipated by regulation valves. The feasibility of such a sustainable strategy depends on the potential of energy savings and the amount of energy embedded in water streams, assessed by means of efficiency measures. Alternatively, energy savings can be pursued if the water is directly pumped to the network, bypassing the elevated reservoir. This study focuses on the comparison of two solutions to supply a real network, assessed as a case study. The first solution consists of water pumping to a reservoir, located upstream of the network; the excess of energy is saved by the employment of a pump as turbine (PAT). The second scenario is characterized by a smaller pressure head since a direct variable speed pumping is performed, bypassing the reservoir. The comparison has been carried out in terms of required energy, assessed by means of a new energy index and two literature efficiency indices. Furthermore, differing design conditions have been analyzed by varying the pumping head of both the scenarios, corresponding to different distances and elevation of the water source.

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Section: Discussionsupporting

confidence: 84%

Section: Energy Indices Under Differing Boundary Conditionsmentioning

confidence: 99%

Section: Energy Indices Under Differing Boundary Conditionsmentioning

confidence: 99%

See 1 more Smart Citation

A Comparison of Energy Recovery by PATs against Direct Variable Speed Pumping in Water Distribution Networks

Morani

Carravetta

Giudice

et al. 2018

Fluids

View full text Add to dashboard Cite

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“…Water pressurized networks were designed without considering tanks in the optimization process, but researchers and practitioners have made an effort to integrate them and optimize their size [45][46][47][48] in real-world operation projects. Tanks are of paramount importance in WPNs [45] because of their use as water storage (filled during the day while it empties, releasing the volume at night) for daily use and in emergencies, but they present inconveniences regarding higher water age and higher energy consumption [49], and some approaches have considered the effect of tanks in the indirect water supply [50]. Recent works highlight batteries as an environmental alternative [51][52][53] in many types of standalone PV systems [54], to concentrate the solar energy to a higher power, and to solve irregularities in the solar irradiation [55].…”

Section: Introductionmentioning

confidence: 99%

Standalone Photovoltaic Direct Pumping in Urban Water Pressurized Networks with Energy Storage in Tanks or Batteries

2020

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Photovoltaic energy production is nowadays one of the hottest topics in the water industry as this green energy source is becoming more and more workable in countries like Spain, with high values of irradiance. In water pressurized systems supplying urban areas, they distribute energy consumption in pumps throughout the day, and it is not possible to supply electromechanical devices without energy storages such as batteries. Additionally, it is not possible to manage energy demand for water consumption. Researchers and practitioners have proven batteries to be reliable energy storage systems, and are undertaking many efforts to increase their performance, capacity, and useful life. Water pressurized networks incorporate tanks as devices used for accumulating water during low consumption hours while releasing it in peak hours. The compensation tanks work here as a mass and energy source in water pressurized networks supplied with photovoltaic arrays (not electricity grids). This work intends to compare which of these two energy storage systems are better and how to choose between them considering that these two systems involve running the network as a standalone pumping system without being connected to electricity grids. This work also calculates the intermediate results, considering both photovoltaic arrays and electricity grids for supplying electricity to pumping systems. We then analyzed these three cases in a synthetic network (used in earlier research) considering the effect of irradiation and water consumption, as we did not state which should be the most unfavorable month given that higher irradiance coincides with higher water consumption (i.e., during summer). Results show that there is no universal solution as energy consumption depends on the network features and that energy production depends very much on latitude. We based the portfolio of alternatives on investments for purchasing different equipment at present (batteries, pipelines, etc.) based on economic criteria so that the payback period is the indicator used for finding the best alternative, which is the one with the lowest value.

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“…Water-related energy and related greenhouse gas emissions are important issues in future cities (Kenway, McMahon, Elmer, Conrad & Rosenblum, 2013). Water energy nexus is an issue of increasing importance (Gómez, Cabrera, Balaguer & Soriano, 2015). Resource attributes of water and energy along with the large infrastructure systems conventionally used to source, transport, and distribute them, plus the recovery of waste, make water and energy core resources to take into consideration for urban planning in a nexus framework (Scott, Crootof & Kelly-Richards, 2016).…”

Section: Introductionmentioning

confidence: 99%

The incorporation of the study into water consumption in energy audits in schools

Sánchez-Torija

Gómez-Rubiera

Frutos

2017

rdlc

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The approach of energy audits usually disregards the study of water as it considers that the supply does not involve energy consumption within the building. This paper aims to make visible both the energy footprint involved in ensuring safe water for human consumption and the collection and treatment of waste water. Furthermore, a methodology for conducting an energy audit is shown for the study of water consumption and applies it to a school to verify whether the measures proposed to reduce the consumption of water and the energy associated to it are viable. A school is chosen for three reasons. It is medium sized so the results can be extrapolated to other buildings. It presents a relevant water consumption due to the number of users, but without it being as high as a swimming pool might be. Finally it does not have a water heating system (there are no showers in the gym) so it only studies the energy consumption associated with drinking water without incorporating the effects of energy consumption for water heating.Key words: Water, energy audit, energy efficiency, sustainability, school. ResumenEl planteamiento de las auditorías energéticas al uso habitualmente prescinde del estudio del agua al considerar que dicho suministro no conlleva un consumo de energía dentro del edificio. El presente trabajo pretende visibilizar la huella energética que supone disponer de agua apta para el consumo humano así como la recogida y tratamiento de las aguas una vez han sido usadas. Adicionalmente se muestra una metodología para la realización de la auditoría energética en cuanto al estudio del consumo de agua se refiere y se aplica a un centro docente para verificar si las medidas que se proponen para reducir el consumo de agua y de energía asociado al mismo son viables. Se escoge un centro docente para el estudio por tres motivos: tiene un tamaño medio por lo que sus resultados son extrapolables a otros edificios; presenta un consumo de agua significativo debido al número de usuarios, pero sin resultar tan elevado como pudiera ser una piscina; finalmente, no dispone de instalación de calentamiento de agua (no hay duchas en el polideportivo) por lo que se puede estudiar exclusivamente el consumo de energía asociado al consumo de agua sin incorporar los efectos del consumo energético para calentar el agua.

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Direct and Indirect Water Supply: An Energy Assessment

Cited by 21 publications

References 6 publications

A Comparison of Energy Recovery by PATs against Direct Variable Speed Pumping in Water Distribution Networks

A Comparison of Energy Recovery by PATs against Direct Variable Speed Pumping in Water Distribution Networks

Standalone Photovoltaic Direct Pumping in Urban Water Pressurized Networks with Energy Storage in Tanks or Batteries

The incorporation of the study into water consumption in energy audits in schools

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