Energy-water-environment nexus underpinning future desalination sustainability

Energy-water-environment nexus is very important to attain COP21 goal, maintaining environment temperature increase below 2 °C, but unfortunately two third share of CO2 emission has already been used and the remaining will be exhausted by 2050. A number of technological developments in power and desalination sectors improved their efficiencies to save energy and carbon emission but still they are operating at 35% and 10% of their thermodynamic limits. Research in desalination processes contributing to fuel World population for their improved living standard and to reduce specific energy consumption and to protect environment. Recently developed highly efficient nature-inspired membranes (aquaporin & graphene) and trend in thermally driven cycle's hybridization could potentially lower then energy requirement for water purification. This paper presents a state of art review on energy, water and environment interconnection and future energy efficient desalination possibilities to save energy and protect environment

More carrot than stick: Encouraging computer programming in thermal design projects

Students will do almost anything to avoid using thermal-property tables. In this paper, Matlab-based thermal-property software is described as an enticement for students to do computer programming in the design of thermal systems. Downloaded shareware was used for steam properties in a steam-cycle project, and an air-property package was developed for use with a gas-turbine project. Although the use of computer programming required considerable effort by both instructor and students, most students did gain a better appreciation of the utility of writing computer programs as part of engineering design. Student evaluations of the course were not significantly affected compared to semesters in which computer programming was not encouraged

Mathematical Modeling of Multi-Effect Thermal Vapor Compression Desalination Processes

A mathematical model has been developed to predict the performance of any multi-effect desalination with thermal vapor compression (MED-TVC). The model consists of mass and energy balances, rate equations, correlations for film heat transfer coefficients for horizontal falling film evaporators, and correlations for physical and thermodynamic properties for saline water. The mathematical model has been coded using visual Basic and assigned the name MEDUAE. Computer simulations were executed, using the in-house developed program (MEDUAE) and the commercial software package Evapolund using design and plant operating data of 3 different MED-TVC desalination plants in UAE. The main objectives have been to calibrate and verify the general nature of the developed computer program, and to check some critical plant design values. The process variables that were used in all simulations include the saturation temperature of vapor streams leaving each effect, the flow rate of water produced (plant capacity), the concentration of brine rejected, the heat transfer area of evaporators at both clean and fouled conditions, and the overall heat transfer coefficients. The simulation results obtained from both MEDUAE and Evapolund are very similar, suggesting the reliability of the mathematical model and the in-house developed program. The results also revealed that, in designing this type of desalination plants, the process designers and plant contractors add a safety margin of about 10% to the heat transfer area of all evaporators to maintain the plant capacity at fouled conditions

Italian Offshore Platform and Depleted Reservoir Conversion in the Energy Transition Perspective

New hypotheses for reusing platforms reaching their end-of-life have been investigated in several works, discussing the potential conversions of these infrastructures from recreational tourism to fish farming. In this perspective paper, we discuss the conversion options that could be of interest in the context of the current energy transition, with reference to the off-shore Italian scenario. The study was developed in support of the development of a national strategy aimed at favoring a circular economy and the reuse of existing infrastructure for the implementation of the energy transition. Thus, the investigated options include the onboard production of renewable energy, hydrogen production from seawater through electrolyzers, CO2 capture and valorization, and platform reuse for underground fluid storage in depleted reservoirs once produced through platforms. Case histories are developed with reference to a typical, fictitious platform in the Adriatic Sea, Italy, to provide an engineering-based approach to these different conversion options. The coupling of the platform with the underground storage to set the optimal operational conditions is managed through the forecast of the reservoir performance, with advanced numerical models able to simulate the complexity of the phenomena occurring in the presence of coupled hydrodynamic, geomechanical, geochemical, thermal, and biological processes. The results of our study are very encouraging, because they reveal that no technical, environmental, or safety issues prevent the conversion of offshore platforms into valuable infrastructure, contributing to achieving the energy transition targets, as long as the selection of the conversion option to deploy is designed taking into account the system specificity and including the depleted reservoir to which it is connected when relevant. Socio-economic issues were not investigated, as they were out of the scope of the project

Critical Metals in the Path towards the Decarbonisation of the EU Energy Sector: Assessing Rare Metals as Supply-Chain Bottlenecks in Low-Carbon Energy Technologies

In order to tackle climate change, to increase energy supply security and to foster the sustainability and competitiveness of the European economy, the EU has made the transition to a low-carbon economy a central policy priority. This report builds on the first study conducted in 2011 (Critical Metals in Strategic Energy Technologies), where critical metals were identified which could become a bottleneck to the supply-chain of various low-carbon energy technologies. The first study concentrated on the six SET-Plan technologies, namely: wind, solar (both PV and CSP), CCS, nuclear fission, bioenergy and the electricity grid. Fourteen metals were identified to be a cause for concern. After taking into account market and geopolitical parameters, five metals were labelled ‘critical’, namely: tellurium, indium, gallium, neodymium and dysprosium. The potential supply chain constraints for these materials were most applicable to the deployment of wind and solar energy technologies. In the follow-up study reported here, other energy and low-carbon technologies are investigated that not only play an important role in the EU's path towards decarbonisation but also may compete for the same metals as identified in the six SET-Plan technologies. Eleven technologies are analysed including fuel cells, electricity storage, electric vehicles and lighting. As in the first report, sixty metals, i.e. metallic elements, metallic minerals and metalloids are considered; only iron, aluminium and radioactive elements were specifically excluded. Graphite was also included, reflecting its status as a critical raw material. Where possible, the study models the implications for materials demand as a result of the scenarios described in the EU Energy Roadmap 2050. Consequently, the results obtained in the first study are updated to reflect the data that has become available in the roadmap. This second study found that eight metals have a high criticality rating and are therefore classified as ‘critical’. These are the six rare earth elements (dysprosium, europium, terbium, yttrium, praseodymium and neodymium), and the two metals gallium and tellurium. Four metals (graphite, rhenium, indium and platinum) are found to have a medium-to-high rating and are classified as ‘near critical’, suggesting that the market conditions for these metals should be monitored in case the markets for these metals deteriorate thereby increasing the risk of supply chain bottlenecks. Metals demand in the electric vehicle, wind, solar and lighting sectors were identified to be of particular concern. As in the first report, ways of mitigating the supply-chain risks for the critical metals are considered. These fall into three categories; increasing primary supply, reuse/recycling and substitution In addition, a number of topics were identified as possibly meriting further research, but could not be considered within the immediate scope of this study. These include conducting further studies to look at raw materials requirements for hybrid and electric vehicles for a wider range of technology uptake and penetration scenarios; developing new and more detailed scenarios for the uptake and technology mix of options for stationary energy storage; undertaking similar studies in defence and aerospace; improving statistics on the contribution of recycling to world production for a number of metals; and investigating the contribution of greater traceability and transparency to reducing raw materials supply risk. Finally, it is important not to overstate the bottlenecks due to the risks of raw material shortages for key decarbonisation technologies. This is because there are still many years before the large uptake of some technologies and in the coming years, there are numerous options that will become available to mitigate the risks identified.JRC.F.6-Energy systems evaluatio

Conjunctive Management for Groundwater-Surface Water Resources: Numerical Modeling and Potential Assessment of Managed Aquifer Recharge (MAR) at Lower Rio Grande Valley in South Texas

Texas is well known to frequent floods and droughts, and yet has mounting concerns in very imbalanced water availability and water demands from growth in population and economical activities. Capturing and storing water is essential to long-term and climate-smart management of the “already-scarce” water resources. This study aimed to apply numerical modeling to evaluate potentials and impacts of Managed Aquifer Recharge (MAR) to regional groundwater systems in the Lower Rio Grande Valley. Using Visual MODFLOW Flex 3D package, different scenarios were simulated for groundwater flow patterns and storage capacities. Water injections tested ranged between 7.30x105 ft3 to 3.65x109 ft3 , which were comparable to existing ASR capacities in Texas. This study examined flow patterns and water table changes at one selected MAR site with injected water volume equivalent to 3~5% of flood water from Hurricane Hanna (major flood event in LRGV). Giving current assumptions and limited scenarios ran, study results showed that MAR injections had minimal impacts to regional coastal aquifers. LRGV are suitable for MAR using treated water or when there is surplus water, i.e., water from flooding as alternative mitigations. More studies such as data and simulations are needed to better plan and build water resilience

AI and OR in management of operations: history and trends

The last decade has seen a considerable growth in the use of Artificial Intelligence (AI) for operations management with the aim of finding solutions to problems that are increasing in complexity and scale. This paper begins by setting the context for the survey through a historical perspective of OR and AI. An extensive survey of applications of AI techniques for operations management, covering a total of over 1200 papers published from 1995 to 2004 is then presented. The survey utilizes Elsevier's ScienceDirect database as a source. Hence, the survey may not cover all the relevant journals but includes a sufficiently wide range of publications to make it representative of the research in the field. The papers are categorized into four areas of operations management: (a) design, (b) scheduling, (c) process planning and control and (d) quality, maintenance and fault diagnosis. Each of the four areas is categorized in terms of the AI techniques used: genetic algorithms, case-based reasoning, knowledge-based systems, fuzzy logic and hybrid techniques. The trends over the last decade are identified, discussed with respect to expected trends and directions for future work suggested