Advanced MED process for most economical sea water desalination

The feasibility of heavy battery electric trucks

The efficacy of seawater desalination has a profound impact in terms of reducing the water demand-supply gap especially in dry and arid countries. In UAE, 90% of the country’s water supply relies solely on desalinated water where a high share of the desalination plant’s output is aimed towards water supply for residential buildings. The hospitality sector consumes 50% more than the global average. The purpose of this paper is to determine the technical and economic viability for the integration of a concentrated photovoltaic thermal (CPV/T) system with a hybrid reverse osmosis (RO) and multi effect desalination (MED) plant. The system was designed to meet the water demand of a luxurious beach resort located in Fujairah. The resort accommodates about 110 occupancies per day. The estimated water consumption is 51m3/hr. The proposed system was analyzed with the aid of numerical simulation and reverse engineering calculations. The capacity of the CPV/T module, which represents the electrical and thermal energy output supplied to the RO and MED plant was determined using TRNSYS software. The results showed an efficient solar system providing electricity of 3500 kWh/year and thermal energy of 14,100 kWh/year, that is required to meet the water consumption of the hotel. In addition, the proposed system proved to be economically feasible, achieving a payback period of 3.6 years under an average lifetime of 20 years.

Water is one of the most stressed resources on the planet. The limited availability of fresh water and the high cost of transportation have led to an increased interest in water desalination technologies. The two main categories of desalination techniques are membrane desalination and thermal desalination. Membrane technologies include pressure driven and electrical driven membranes. On the other hand, thermal desalination includes: multi-effect desalination (MED), multi-stage flash (MSF) desalination, and mechanical vapor compression desalination. Multi-effect desalination plants are usually made of a series of evaporators (also known as effects). In each effect, hot steam flows inside the tubes and evaporates the seawater that falls on the outside of the tubes. The vapor formed at each effect flows to the next effect and acts as the heating medium for the falling seawater. The prevailing flow mode of the falling seawater (i.e. droplet, jet, or sheet) influences heat and mass transfer as well as dry out in the evaporators of Multi-Effect Desalination (MED) plants. The objective of this paper is to predict and discuss the prevailing falling film flow modes in the evaporators of MED plants, under different operating conditions. The paper demonstrates the transitional Reynolds numbers between the main falling film modes for seawater. This closes a gap in the literature where there is a dearth of mode transition data for seawater. The effect of fluid properties and tube geometry on the transitions is discussed in details. The accuracy of the predicted transitional Reynolds numbers is evaluated via uncertainty quantification techniques.

Fresh water production is one of the main concerns in the new century. Population grows fast and potable water resources are decreased. In the other hand energy crises would also be another issue that must be well addressed by the politicians and also scientists. Developing desalination plant with using renewable energy (particularly solar energy) is one of the important options to overcome these concerns. Thus many researchers have been working on different desalination plants to find the best conditions and to realize the most efficient performances for different cycles. Different approaches have been used to achieve the most efficient conditions or to find the optimum operation and design conditions. Some of the researchers used parametric study approach while many other adopted different conventional optimization algorithms for these tasks. The algorithms such as gradient based algorithm, genetic algorithm, search and pattern algorithm and neural network method have been used in the field of desalination. For instance; Ophir and Lokiec (2005) described the design principles of a MED plant and various energy considerations that result in an economical MED process and plant. Kamali and Mohebbinia (2007) showed that parametric study as one of the optimization methods on thermo-hydraulic data strongly helps to increase GOR value inside MED-TVC systems. Shamel and Chung (2006) used parametric study to find the optimum condition of a Reverse Osmosis (RO) system for sea water desalination. Metaiche et al (2008) developed optimization software, Desaltop, for RO system for water desalination. They used genetic algorithm to find suitable operating parameters and also to find appropriate type of membrane. Al-Shayji (1998) used neural network method for optimization of large-scale commercial desalination plants. Djebedjian et al. (2008) used genetic algorithm for optimization of a reverse osmosis desalination system. Mussati et al. (2003) used an evolutionary algorithm for the optimization of Multi Stage Flash (MSF) system. Finding the optimum conditions is a major challenge on the desalination plant studies. The plant performance depends on several different variables and constraints that need exhausting efforts to find the optimum conditions. This chapter introduces Design of Experiment (DOE) method as a statistical tool for optimization of desalination systems. Thus two different desalination plants; Multi-Effect Desalination (MED) system and solar desalination using humidification–dehumidification cycle (SDHD) have been considered to show the ability of DOE method for optimizing such systems. These both desalination plants could use the low graded heating energy sources

This article presents thermodynamic analyses on the integration of transcritical CO2 cooling systems with multi‐effect desalination (MED) systems. The study reveals improvements in energy efficiency, water production capacity, and cost‐effectiveness achieved through this integration. The two‐module system achieved 55.38% lower energy consumption and 24.6% more freshwater production compared to the single‐module system. Annual operating costs were also reduced by 10%. These results were obtained through a combination of energy and exergy analyses, employing thermodynamic modeling to assess system interactions and performance enhancements. Waste heat from the CO2 cycle was utilized for steam generation in the MED process, enhancing thermal synergy. These findings indicate that integrating transcritical CO2 systems with MED is widely applicable in water‐scarce regions. Future studies should investigate performance under various climatic conditions, potential for large‐scale deployment, and integration with renewable energy sources. This work contributes to sustainable water and energy management through innovative system design and heat recovery mechanisms.

Integration of several in-house heat stations containing of multiple boilers of different capacity and energy carriers can be economical profitable. This study contains further analyze and development of previous work by Riise and Sørensen [1-3]. Boiler start-up costs effect of the overall energy cost has been investigated and found to have an impact of boiler configurations in a system based on lowest specific running energy cost. A study of operational hours of boilers indicates if boilers can be dismounted form the integrated system. It is also performed simulations for lowest energy consumption instead lowest energy cost. Finally a heat pump model is introduced and analyzed. Introduction of the heat pump reduces the total energy cost even if the heat sink is increased with a fourth building.

scarcity. Underground water is mostly saline and other sources are small seasonal rivers and dams that collect rain water for sprawling population. Desalination plants can alleviate this problem to an extent. This paper examines various desalination plants, provides detailed technical discussion of Passive Vacuum Flash Type Solar Thermal technology and compares it with Concentrating Solar Desalination technology. Comprehensive levelised cost of water calculations are laid out for conventional Reverse Osmosis (RO) plant, Photovoltaic (PV) RO plant, conventional thermal Multi Effect Desalination (MED) plant and solar thermal MED plant. PVRO with cost of PKR 0.39 per gallon is the most suitable option.

Commercial lithium-ion (Li-ion) batteries built with Ni- and Co-based intercalation-type cathodes suffer from low specific energy, high toxicity and high cost. Conversion-type cathodes offer an opportunity to overcome such limitations.

In recent years, energy storage and conversion have become key areas of research to address social and environmental issues, as well as practical applications, such as increasing the storage capacity of portable electronic storage devices. However, current commercial lithium-ion batteries suffer from low specific energy and high cost and toxicity. Conversion-type cathode materials are promising candidates for next-generation Li metal and Li-ion batteries (LIBs). Metal fluoride materials have shown tremendous chemical tailorability and exhibit excellent energy density in LIBs. Batteries based on such electrodes can compete with other envisaged alternatives, such as Li-air and Li-S systems. However, conversion reactions are typically multiphase redox reactions with mass transport phenomena and nucleation and growth processes of new phases along with interfacial reactions. Therefore, these reactions involve nonequilibrium reaction pathways and significant overpotentials during the charge-discharge process. In this review, we summarize the key challenges facing metal fluoride cathode materials and general strategies to overcome them in cells. Different synthesis methods of metal fluorides are also presented and discussed in the context of their application as cathode materials in Li and LIBs. Finally, the current challenges and future opportunities of metal fluorides as electrode materials are emphasized. With continuous rapid improvements in the electrochemical performance of metal fluorides, it is believed that these materials will be used extensively for energy storage in Li batteries in the future.

The article is devoted to the study of the processes of movement and separation of components in a seed mixture under the conditions of a vibro-pneumatic layer. The problem of competitiveness of grain production is highlighted through the use of seeds with high sowing qualities. The conducted research focuses on methods of improving the quality of seeds, in particular on their separation in a vibro-pneumatic environment according to physical and mechanical properties and seed density. The authors indicate a close relationship between sowing qualities and seed density. The study shows that modern technical means, such as vibropneumoseparators, have limited efficiency due to low specific load and high energy costs. However, the authors suggested improving the efficiency of seed separation in the vibro-pneumopulse layer of the grain medium, which can lead to the creation of competitive combined vibro-pneumoseparators for separating seeds by density. Graphical dependences of the main parameters of separation of seed mixtures were obtained. The main elements for CFD modeling are substantiated and the design and kinematic parameters of the working surface of the vibration-pneumopulse separator are established. The created mathematical models make it possible to predict the speed of movement of components with a small density in the vibro-pneumopulse grain layer, taking into account various factors. Based on the research results, a modernized vibro-pneumopulse separator was developed and manufactured, which increases the specific load on the sieve and reduces energy costs during seed separation. According to experimental data, an increase in air flow speed from 0.6 to 1.4 m/s helps to increase the efficiency of separating wheat seeds, reaching 70%, while the loss of high-quality seeds to other fractions does not exceed 3% (with a permissible 10%).

Quantitative techno-economic comparison of a photovoltaic/wind hybrid power system with different energy storage technologies for electrification of three remote areas in Cameroon using Cuckoo search algorithm

The aim of the present study is to manufacture and evaluate batch butter churning machine for butter and buttermilk production from sweet or fermented cream. The new butter making machine consists of five main parts: power source, transmission system, collection cream vessel and cooling unit. The cooling unit consists of five parts: evaporator, expansion valve, condenser, fan, receiver tank, and compressor. Laboratory experiments were conducted to optimize cream loading ratio, churning time and churning temperature. While the churn machine performance was evaluated in terms of butter and buttermilk amounts,buttermilk fat percentage, churn efficiency, specific energy and operational cost of butter churn. The experimental results reveal that the churning machine is recommended to be used to give the highest butter production of 21.20 kg/h with lower specific energy and operational cost of 23.11 kW.h/Mg and 188.21 L.E/Mg, respectively at cream loading ratio of 45 kg/h, churning temperature of 6° C and churning time of 15 min under constant fan speed of 600 rpm.

The aim of the present study is to construct and evaluate a centrifugal milk separator for cream and skim milk production. The milk separator consists of five main parts: power source, transmission system, collection milk vessel, centrifugal separation unit and production collectors. The centrifugal separation unit consists of three parts: housing, separated discs with totally number of 40 conical discs collect and fix in the housing together and stuck base, which fastening the conical discs and the housing together through a stud and Hex. Hd. Nut. Laboratory experiments were conducted to optimize milk feeding rate, separation rotating speed and raw milk temperature degree. While the separator performance was evaluated in terms of cream and skim milk amounts,skim milk fat percentage, separation efficiency, specific energy and operational cost of milk separation. The experimental results reveal that the milk separator is recommended to be used under the following conditions to give the highest cream amount of 35 kg/h with lower specific energy and operational cost of 25.14 kW.h/Mg and 228.60 L.E/Mg, respectively: - Milk feeding rate to the conical separating unit of 400 kg/h. - Separation rotating speed of 8000 rpm. - Temperature degree for the raw milk of 37° C.

In multi-effect desalination (MED) plants, the evaporators are usually of horizontal falling film type. For this kind of evaporators, high heat transfer coefficient can be achieved over low temperature difference and low spray density/liquid load. The current operating temperature range of MED plants is from 65 to 40 °C and researchers are trying to widen this range (85–5 °C), in order to enhance desalted water productivity. In this study, review of heat transfer coefficient correlations for falling films was carried out. The heat transfer coefficient prediction by different studies was compared with respect to film Reynolds number and working temperature. It was found that the empirical correlations by Fujita and Tsutsui, and Danilova et al. were better in evaluating heat transfer coefficient for MED application. It was concluded that increasing the top brine temperature (TBT) of MED evaporator is more beneficial than decreasing the lower temperature. The estimated heat transfer coefficient at 5 °C was 30–65% was less than that of heat transfer coefficient at 85 °C.KeywordsFalling filmHeat transfer coefficientHorizontal tubeMED

This work suggests a solution for preventing/eliminating the predicted Sea Level Rise (SLR) by seawater desalination and storage through a large number of desalination plants distributed worldwide; it also comprises that the desalinated seawater can resolve the global water scarcity by complete coverage for global water demand. Sea level rise can be prevented by desalinating the additional water accumulated into oceans annually for human consumption, while the excess amount of water can be stored in dams and lakes. It is predicted that SLR can be prevented by desalination plants. The chosen desalination plants for the study were Multi-Effect Desalination (MED) and Reverse Osmosis (RO) plants that are powered by renewable energy using wind and solar technologies. It is observed that the two main goals of the study are fulfilled when preventing an SLR between 1.0 m and 1.3 m by 2100 through seawater desalination, as the amount of desalinated water within that range can cover the global water demand while being economically viable.