The worldwide lowest specific energy consumption measured in a seawater desalination plant – Real integration and opportunities of improvement

An energy recovery device with variable damping for the Wave-Adaptive vehicle vibration control

Pumps as turbines (PATs) are widely applied in micro-hydropower stations and chemical industries as economical and efficient energy recovery devices. This study used numerical simulations and entropy dissipation theory to investigate the influence of four draft tube diffusion angles (β0, β1, β2, and β3) on the hydraulic performance and energy losses of a double-suction centrifugal PAT. The results show that the diffusion angle exhibits a complex nonlinear effect on head, efficiency, and shaft power across different flow rates. Under low-flow conditions (0.6Qd), β2 reduces efficiency by 9.27%, whereas under high-flow conditions (1.4Qd), β3 improves efficiency by 1.01%. Entropy analysis reveals that total entropy generation follows an approximately parabolic trend with flow rate, reaching its minimum near the design condition. Among the schemes, β1 and β3 effectively reduce total entropy generation, with β3 achieving a 5.51% reduction under high-flow conditions. The impeller is identified as the dominant source of energy loss (approximately 53% of entropy production), followed by the draft chamber (approximately 30%). Further analysis indicates that entropy generation in the draft chamber primarily arises from turbulent dissipation and wall friction and is highly sensitive to the diffusion angle. Under high-flow conditions, β3 reduces draft chamber entropy production by 7.44%, whereas under low-flow conditions, larger diffusion angles increase entropy production. Thus, optimizing the diffusion angle not only improves impeller flow conditions but also effectively reduces system energy losses, particularly under high-flow and off-design operating conditions. This work provides theoretical insights and engineering guidance for the optimized design of PAT draft tubes.

Current insights and future outlooks of energy-efficient desalination plants: A comprehensive bibliometric analysis

膜分离技术越来越广泛地应用在环保水处理和物料分离行业，能量回收是其重要的节能措施。目前，能量回收装置在反渗透海水淡化领域应用最为广泛，由于海水淡化工艺多采用一段膜装置，正位移式能量回收装置的节能效果更具有优势。而在环保及物料分离领域常见的多段膜系统中，能量回收装置的应用较少，应用方式的选择和节能效果的评价依据尚不完善。文章对能量回收装置的分类、原理、技术特点及其使用工艺进行了介绍，并通过盐湖资源利用领域应用案例的深入分析，对比了常规系统、正位移系统和离心式系统三种不同系统的能耗，探讨了在多段膜系统中不同形式能量回收装置选择的依据，为能量回收装置在多段系统中的广泛应用提供支撑。

Energy recovery in brackish water reverse osmosis: Modeling, integration, and cost-saving analysis

Arid zones, such as the MENA regions and the Sahara countries, are experiencing significant water stress. To address this global challenge, desalination technologies provide a crucial solution, particularly the reverse osmosis (RO) technique, which is widely used to treat Seawater or Brackish water. Mauritania is among the countries facing a scarcity of potable water resources and relies on desalination technologies to meet its water demand. In this work, a numerical and experimental study was carried out on the functional and productive parameters of the Nouadhibou desalination plant in Mauritania using MATLAB/Simulink (R2016a). The study considered two operating scenarios: with and without the energy recovery unit. The objective of this paper is to perform an analytical study of the operating procedures of the Nouadhibou RO desalination plant by varying several parameters, such as the pressure exchanger, and the feed water mixing ratio in the pressure exchanger unit, etc., in order to determine the system’s optimal operating point. This paper analyzes the system’s performance under different conditions, including recovery rate, feed water temperature, and PEX splitter ratio. In Case No. 1 (without a pressure recovery unit), and with a recovery rate of 20%, doubling the plant’s productivity from 400 to 800 m3/d requires 400 kW of power. In contrast, in Case No. 2 (with a pressure recovery unit), achieving the same productivity requires only 100 kW, with a 75% of energy saving. When the desalination plant operates at a productivity of 400 m3/d@40%, the SPC decreases from 6 kWh/m3 (Case No. 1) to 2.7 kWh/m3 (Case No. 2), resulting in a 55% specific power consumption saving. The results also indicate that power consumption increases with both feed water temperature and PEX splitter ratio, while variations in these parameters have a negligible effect on permeate salinity.

With the global freshwater scarcity, Seawater desalination particularly through reverse osmosis (RO), is a solution to address the problem. Nowadays, seawater desalination is used in various countries, like The United Arab Emirates (UAE), Africa and China, etc. However, despite its huge benefits, the technology is also accompanied by adverse environmental effects, like brine discharge which can lead to localized changes in salinity and subsequently affect the water quality and biodiversity of the area. Huge energy consumption is another issue, as most seawater desalination plants need the electrical energy to control the high-pressure pump which means the enormous energy requirement. Noise pollution, CO₂ emissions, biofouling and invasive species also impact on marine ecosystems. These effects can be minimized by innovative solution, such as improving RO membrane, zero liquid discharge technology, renewable energy technologies, energy recovery devices and continuous environmental monitoring and regulation. This paper investigates ecological consequences in seawater desalination processes, highlights the potential adverse effects, and discusses the mitigation measures.

This study presents a novel sustainable approach to desalination by integrating tidal energy with reverse osmosis (RO) technology, enhanced by Kenics static mixers (KSM) to improve mass transfer. A three-dimensional computational fluid dynamics (CFD) model analyzes the optimized ROKSM configuration, featuring three rows of KSM at a 30° twist angle, achieving a 1.6-fold increase in the Sherwood number (from 8.5 to 13.6 at Re = 300) and a 23% increase in water flux (from 13 to 16 L/m²h) by reducing concentration polarization. However, this comes with a 4.7-fold increase in pressure drop, partially mitigated by Energy Recovery Devices (ERDs), resulting in a net specific energy consumption of 2.2–2.5 kWh/m³. Tidal energy from global sites (600–1700 kW) provides feed pressures of 17–80 bar, with energy storage and pressure regulation ensuring stable RO operation despite tidal fluctuations. Techno-economic analysis indicates a potential levelized cost of water (LCOW) reduction of 15–20% (to 0.45–0.65 $/m³) under realistic conditions, though challenges in intermittency and costs require further validation. The integrated approach, validated with less than 5% error against experimental data, demonstrates significant potential for sustainable freshwater production, offering a scalable solution for coastal regions worldwide.

Seawater desalination: A review of technologies, environmental impacts, and future perspectives

Abstract Reverse osmosis (RO) is the most widely used membrane-based desalination technology. However, it still requires a significant amount of energy to produce fresh water. The highly concentrated rejected solution of the RO process is typically wasted. The idea is to use it for pressure-retarded osmosis (PRO). A SWRO–PRO hybrid system could potentially further reduce the specific energy consumption (SEC) of the system. In this paper, we are modelling the membrane unit for both RO and PRO in detail. The mathematical model describes the important flow quantities along the flow direction of the membrane. For a realistic approximation, we include internal concentration polarization (ICP) and external concentration polarization (ECP) effects. Together with a model for a modern energy recovery device (ERD), we are able to implement and simulate a complete SWRO–PRO hybrid system. Finally, we optimize the operating pressures of a conventional RO system and the operating conditions of a hybrid system.

Low grade thermal energy generated during the operation of personal computers is often directly emitted in the form of heat dissipation, resulting in significant energy waste. Thermoelectric Generator (TEG) is an ideal solution for PC waste heat recovery due to their simple structure, lack of mechanical parts, and suitability for low-temperature differential environments. Inspired by the waste heat recovery scheme of the data center, this paper designs a set of PC waste heat recovery device based on thermoelectric conversion. This study used the method of combining experimental test and theoretical analysis. By building the PC waste heat recovery experimental platform, the temperature data and TEG power generation performance parameters of the CPUs were collected, and verified and analyzed with statistical data. The PC waste heat recovery system designed in this study can generate 7.98 kWh per year per unit; If applied to 1% of Chinese PCs (about 2.225 million units), the annual emission reduction can be equivalent to the carbon sequestration effect of planting 450000 trees. The experimental results provide a feasible technical scheme for the recovery of low-grade thermal energy.

Application of feed seawater overflush in three-cylinder valve-controlled energy recovery device

Liquid flow and mixing investigation inside rotary energy recovery device: A numerical study

Numerical investigation on a quaternary-driven rotary energy recovery device for desalination system: Performance evaluation and theoretical validation

A comprehensive modeling approach for intricate bearing flows within a rotary energy recovery device

The first goal of this study is to examine the performance of a semi-empirical model used for calculating specific energy consumption (SEC) in reverse osmosis desalination. We have introduced a simulation tool (SECSM) to compare this semi-empirical model (SECSEM) and the SECSM. It's worth noting that the simulation model is open source and can be easily integrated easily with other software tools. For this comparison, we explored a temperature range T (10°C - 22°C - 35°C), recovery rate R from 30% to 65%, and a pump efficiency range of γ_HPP ~78% to 98%. An increase in these parameters leads to a decrease in SEC (both SECSEM and SECSM) for systems without energy recovery devices (ERD). However, the introduction of an ERD results in a variable change in SECSEM. Under specific conditions of 35°C, a pump efficiency of 98%, and an R of 65%, the SECSEM reaches its minimum values. In the case of the two-stage unit (TS), the SECSEM and SECSM models converge to the same value of 0.28 KWh/m³. Meanwhile, for the single-stage unit (SS), the values are 0.4 KWh/m³ and 0.39 KWh/m³, respectively. Regarding the unit equipped with the BW 400 34 and SW HF 085 31 membranes, in both SS and TS configurations, the energy consumption for both models converge towards the values 0.71 KWh/m³, 0.70 KWh/m³, and 0.95 KWh/m³, 0.94 KWh/m³ respectively. In the second part of this paper, a comparative study to validate this semi-empirical model without ERD against experimental data was conducted. The SECSEM showed values very close to the experimental results. The findings are discussed below.

This study aims to investigate the braking process in automotive Anti-lock Braking Systems, with a particular focus on the relationship between brake disk temperature variation and pyroelectric energy recovery. We developed a detailed numerical simulation model that considers the wheel dynamics, thermal behavior of the brake disk, and the energy generation mechanism of pyroelectric materials. The model is based on the Pacejka “Magic Formula” and incorporates nonlinear factors in slip ratio, ground braking force, brake disk temperature variation, and pyroelectric voltage generation, simulating the braking process at different vehicle speeds. Through simulation analysis, we demonstrate the dynamic changes in brake disk temperature and pyroelectric energy under various speeds, and we explore the impact of vehicle speed on energy recovery efficiency. The results show that as the vehicle speed increases from 25 to 35 m/s, the amount of pyroelectric energy recovered increases from 0.0021 to 0.0061 J, while the brake disk temperature rises from 181.56 to 359.58 °C. This indicates that at higher vehicle speeds, the rapid increase in brake disk temperature enhances the energy conversion efficiency of pyroelectric materials. By introducing nonlinear parameter adjustments, our model more accurately describes the dynamic behavior and energy recovery characteristics during the braking process, particularly at high speeds and extreme conditions. The findings of this study suggest that pyroelectric energy recovery systems have significant potential in the field of automotive braking energy recovery, with energy recovery efficiency notably improving as vehicle speed increases. These insights provide strong theoretical support and experimental evidence for the future design of vehicle energy recovery systems and highlight the direction for system optimization, such as the further improvement of brake disk material properties and energy recovery devices.

In the last decades, marine environment monitoring has gained significant attention as it plays a fundamental role in ecosystem health and anthropogenic impact evaluation. This study presents the development of a sea wave energy recovery device based on piezoceramic harvesting, designed to contribute to the energy self-sufficiency of an environmental monitoring buoy. The system consists of a flexible S-shaped arm anchored to the buoy structure; the buoyancy system at the free end converts wave-induced motion into mechanical stress, deforming the opposite side of the arm, where piezoceramic patches are installed to generate electrical power. An extensive experimental campaign was conducted to perform the electromechanical characterization of the device and to analyze the manufacturing quality of the arm, produced by stereolithographic additive manufacturing. The results demonstrate the ability to harvest kinetic energy across a range of wave frequencies and amplitudes. Under the best conditions, a maximum transfer electric power of 220.2 ± 3.7 µW was reached.

Current energy harvesting devices in the field of human lower limb energy recovery have the problems of low energy recovery efficiency and large mass and volume. To solve these problems, this article proposes a multijoint synergistic energy recovery device based on the concept of synergistic energy recovery, with the aim of allowing one energy harvester to collect negative work from multiple joints simultaneously. The recovery efficiency of the harvester is improved by increasing the energy recovery source. The mechanism achieves synergistic recovery of negative work in multiple joints of the human lower limb. The mechanical structure consists of a four‐bar mechanism, limit switches, a planetary gear system, and a differential mechanism to complete the energy capture and coupling. Multiple energy streams are superimposed in an orderly manner without loss. The experimental results demonstrate the efficient output of this harvester in collecting and coupling energy in the negative work zone of the knee and hip joints. This integrated multijoint energy harvester achieves an output voltage of 118 V under normal human walking conditions. The device achieves a power output of 3.21 W and a power density of 7.32 W kg−1 at 2 Hz.