Reverse Osmosis Desalination Unit Research Articles

Development of a modified gas turbine-based sustainable power generation and water treatment system; Economical/environmental considerations and data-driven optimization

Developing environmentally friendly solutions that optimize existing power plants while considering economic factors is crucial for ensuring sustainable energy production and mitigating environmental impact. This study promotes a gas turbine-based power plant design that prioritizes environmental concerns and underscores its versatility. The proposed setup is composed of various components, including a gas turbine, a Rankine cycle (RC), an organic Rankine cycle (ORC), a reverse osmosis (RO) desalination unit, a proton exchange membrane electrolyzer (PEME), and a hydrogen blending module. This system engenders the simultaneous generation of hydrogen, electrical power, and desalinated water. Additionally, the direct utilization of produced hydrogen in the proposed system offers improved technical performance and serves as an effective means to mitigate greenhouse gas emissions. A resilient programming code is formulated to systematically evaluate the system through the lenses of techno-economic and environmental considerations. Incorporating innovative modifications into the existing system resulted in an 8% cost reduction, a 1.2% decrease in carbon dioxide emissions, and a 5% enhancement in exergy efficiency. To attain optimal performance of the system, a data-driven and machine learning methodology is employed, wherein two distinct optimization scenarios are used to define the conditions that yield the utmost system performance. In the first scenario, the optimal values for cost, exergy efficiency, and normalized CO2 emissions have been computed as 39%, 5963 $/h, and 367.4 kg/MWh, respectively. In the subsequent scenario, the optimized system demonstrates the capability to generate a fresh water flow rate of 840.4 kg/s. Concurrently, the cost rate for the system equates to 7054.5 $/h.

Design and performance analysis of hydro and wind-based power and hydrogen generation system for sustainable development

Renewable energy sources have significance in combating global challenges. In this developed paper, the integration of the hydropower and wind turbine energy conversion system is designed and proposed. The foremost focus of this combined plant is to simultaneously generate clean power, hydrogen, and freshwater through a sustainable way. The developed innovative plant embraced a hydropower plant, wind turbines, a Proton Exchange Membrane unit, and a Reverse osmosis desalination unit. To determine the system performance, detailed thermodynamic performance modeling and sustainability index evaluation are fulfilled on the plant’s indicators. In light of this purpose, several parameters are used to conduct the irreversibility rate, energetic and exergetic efficiency, and other calculations. Along with the examination results, the electricity production rate is calculated as 81591 kW. Moreover, the developed combined system has 61.29 % energetic performance and 57.14 % exergetic performance. The sustainability index value is figured out as 2.33 for the entire system.

Optimal design of a solar-driven Kalina system for combined power and desalination purposes

This research study presents a thermodynamic simulation and exergy analysis of a solar-powered Kalina cycle that is integrated with a reverse osmosis desalination (RO) module and a thermoelectric generator (TEG) system. A parabolic through solar collector (PTSC) provides the required heat to drive designed plant. The thermodynamic simulation and exergy examination of the proposed system are carried out using the Engineering Equation Solver (EES). A parametric study of the presented plant to show the primary parameters impacts on the system operation is conducted. The system in this study generates 212.7 kW of electrical power and 44.46 m3/h. The total energy efficiency of the plant is 24.3 %. The inlet thermal energy from PTSC is 876.5 kW. In addition, the thermoelectric module generates 7.26 kW electrical power. Carried out analyses show that the recuperator has the most significant exergy destruction rate among all system components, with 303.2 kW. The unit responsible for the second major exergy destruction value associated with the RO unit, which accounts for 74.22 kW. To examine the influence of influences of parameters like direct normal irradiance (DNI), turbine inlet pressure, and mass flow rate of the Kalina cycle the system case study is presented. It can be observed that increasing DNI parameter from 750 W/m2 to 1000 W/m2 leads in a net output power increment from 279.1 kW to 372.1 kW and increasing fresh-water production from 41.64 m3/h to 48.09 m3/h. Moreover, the calculation shows that increasing DNI has a positive impact on the TEG unit output power too. Enhancing the inlet turbine pressure increases both net output power and fresh-water production by reverse osmosis unit while this increment diminishes the thermoelectric unit electrical output. It can be observed that increasing turbine inlet pressure from 110 kPa to 200 kPa, increases net output power and fresh-water production by about 6.08 % and 3.5 %, respectively.

Practical design of a small-scale PVRO desalination unit using longtime measured water quality reports: A case study for Khuzestan, Iran

This study aims to present a practical design of a small-scale photovoltaic-powered reverse osmosis desalination unit (PVRO) based on a local river’s 9-year measured water analysis reports for Buzi-ye Seyf village. After preprocessing the dataset, we used WAVE software to design the RO system, considering nine scenarios containing the most extreme possible situations regarding feed water total dissolved solids (TDS) and temperature. Next, considering negligible desalination electricity tariffs in Iran, the photovoltaic system was designed using PVSOL software with two targets: CO2 reduction and peak shaving in daytime peak hours during spring and summer. During these seasons' 184-day period, the PV system managed to meet the energy demand for 154 days, exporting 2332.86 kWh to the grid and importing only 136.8 kWh from the grid on days when energy fell short. It was found that in the feed water TDS of 3035 mg/L, every 10 degree elevation in the feed water temperature results in an 83.33 Wh/m3 reduction in the SEC and a 70.49 mg/L rise in the permeate water TDS. Analyzing the scenarios demonstrated that the influence of increasing TDS had a more significant effect on SEC compared to the reduction in temperature. In addition, the PV system was shown to successfully achieve the task of peak-shaving for the investigated period while preventing 15467 kg of CO2 emissions per year. Thus, the designed system provided a practical way of solving the drinkable water issue in Buzi-ye Seyf and areas with similar conditions.

Nonlinear optimal and multi-loop flatness-based control of induction motor-driven desalination units

In this article, the control problem for the induction-motor driven reverse osmosis in desalination units is solved with the use of (i) a nonlinear optimal control method (ii) a flatness-based control approach which is implemented in successive loops. To apply method (i) that is nonlinear optimal control, the dynamic model of the induction-motor driven reverse-osmosis desalination units undergoes approximate linearization at each sampling instant with the use of first-order Taylor series expansion and through the computation of the associated Jacobian matrices. The linearization point is defined by the present value of the system’s state vector and by the last sampled value of the control inputs vector. To compute the feedback gains of the optimal controller an algebraic Riccati equation is repetitively solved at each time-step of the control algorithm. The global stability properties of the nonlinear optimal control method are proven through Lyapunov analysis. To implement control method (ii), that is flatness-based control in successive loops, the state-space model of the induction-motor driven reverse-osmosis desalination unit is separated into three subsystems, which are connected in cascading loops. Each one of these subsystems can be viewed independently as a differentially flat system and control about it can be performed with inversion of its dynamics as in the case of input–output linearized flat systems. The state variables of the preceding (ith) subsystem become virtual control inputs for the subsequent (i+1th) subsystem. In turn, exogenous control inputs are applied to the first and third subsystem. The whole control method is implemented in three successive loops and its global stability properties are also proven through Lyapunov stability analysis. The proposed method achieves stabilization of the induction-motor-driven reverse osmosis desalination unit without the need of diffeomorphisms and complicated state-space model transformations.

Feasibility study and techno-economic optimization of an efficient renewable-based system for round-the-clock energy harvesting using machine learning approaches: A case study in Khaf city

A novel multi-generation solar-wind system is proposed in this study, uniting solar and wind renewable energy sources to enhance system reliability. The system incorporates hydrogen energy storage for continuous day and night energy harvesting, offering novel advancements in both reliability and uninterrupted energy supply. The system consists of parabolic through solar collectors (PTSCs), wind turbines (WTs), a steam Rankine cycle-thermoelectric generator (SRC-TEG), a reverse osmosis (RO) desalination unit, a proton exchange membrane (PEM) electrolyzer, hydrogen compression unit and a PEM fuel cell (PEMFC). During the day, the system produces power, fresh water and hydrogen, and at night, when the solar cycle is inactive, the system produces power using a fuel cell that consumes the hydrogen stored in the hydrogen tank. Also, the multi-generation system is fully evaluated from the point of view of energy, exergy and economy in both day and night modes. The proposed system is capable of generating 1624.7 kW of power during the day and 1290.4 kW of power at night. In addition, fresh water can be produced at a rate of 24.29 kg/s and hydrogen at a rate of 8.39 kg/h during the day. Moreover, meteorological data identifies Khaf city as highly suitable for harnessing solar and wind energy on an hourly and yearly basis. Furthermore, artificial neural network (ANN) and multi-objective optimization are used to optimize the system performance. In optimal conditions, the exergy round trip efficiency and overall cost rate of the proposed system are 42.75% and 158.93 $/h, respectively.

An adaptive power management approach for hybrid PV-wind desalination plant using recurrent neural networks

In hybrid Photovoltaic (PV)-wind desalination plants, power management is necessary because renewable energy sources such as PV and wind are highly variable. An optimal power management system also helps extend the equipment's life by preventing overloading or underloading of the system. This paper proposes a recurrent neural network (RNN) based power management for a desalination plant. In the proposed work, renewable energy sources like solar and wind are utilized to power the reverse osmosis (RO) desalination unit. The developed RNN model optimizes renewable energy sources while maintaining a stable function of the desalination process. The RNN power management module utilizes historical data to predict the power generation of the PV and wind sources and then adjusts the system's output to meet the power demand of the desalination plant while considering the limitations of the RO unit and the water profile requirements. The developed model was implemented in MATLAB tool, and the results are estimated. Simulation outcomes demonstrate that the developed model improves the hybrid system's performance in terms of resource and battery storage utilization and minimizes energy loss.

Performance of a solar hybrid desalination plant integrated with photovoltaic-thermal collectors for remote regions: Experimental and modeling investigation

Energy and freshwater are the most prioritized needs for any nation nowadays, especially for arid areas. Giving attention to renewable energy sources like solar energy is a must towards a cleaner environment and a world with no need of temporary sources like fossil fuels. Also, a solution to lower the power requirements and costs of desalination hybrid systems should be investigated to overcome the water problem. The present study aims to design and build a novel hybrid desalination plant working with the highest productivity and lowest power consumption. This was done by incorporating a reverse osmosis desalination unit with the conventional solar distiller. The photovoltaic/thermal collectors were utilized to produce electricity as well as a heating unit in addition to the evacuated tube solar collectors, to preheat the hybrid desalination plant feed water. The results presented that the use of photovoltaic/thermal panels and evacuated tube solar collectors as preheating units improved water recovery by 46% and reduced power consumption by 38.34% for the small reverse osmosis unit but the salt rejection decreased by 4%. Cooling the photovoltaic panel increased its electricity production by 24.1% on average. Moreover, the combination of the solar distiller with the reverse osmosis unit on the feed line represents the best configuration which improves the solar distiller’s productivity by 98.32% as compared to separate solar distillers. The cost of freshwater produced is 0.719 $/m3 which is cost competitive compared to previous solar desalination systems.

Feasibility Study of a Reverse Osmosis Desalination Unit Powered by Photovoltaic Panels for a Sustainable Water Supply in Algeria

In recent years, reverse osmosis water desalination has developed rapidly and has become the most competitive and widely used technology in the world. The number of desalination plants is increasing rapidly as freshwater needs increase. Various membrane technologies have been developed and improved, including nanofiltration (NF) and reverse osmosis (RO), whose desalination costs have been relatively reduced. Therefore, this work proposes an experimental study for a small desalination unit based on RO generated by renewable energy, which is mainly suitable for arid regions or desert areas that do not have electricity and water and can be applied for emergency treatment to meet strong freshwater resource needs. In this study, to meet the drinking water demand, a reverse osmosis desalination system is designed and evaluated in order to improve and optimize its operation. This system has a daily capacity of 2 m3. We used brackish groundwater, which has been characterized as reference water, to produce synthetic water for different salinities until seawater. The analysis is based on data obtained from experiments carried out in the standalone RO pilot designed for the production of fresh water. For this purpose, we conducted relevant experiments to examine the influence of applied pressure, salt concentration and temperature on the RO membrane performance. The effects of different factors that affect the energy consumption in the RO desalination process were analyzed, and those with significant influence were explored. The effectiveness of RO desalination coupled with a photovoltaic (PV) energy system is shown. We found the recovery rate for system operation to be 32%. An optimization study is presented for the operation of an autonomous RO desalination system powered by photovoltaic panels. The energy produced by the PV system was used to feed two pumps forthe production of drinking waterwithanRO membrane, under the conditions of the town of Bou-Ismail. As results, a 3 kWp PV system was installed based on the energy demand. The design data have shown that a 3 kWp PV system can power a 1.8 W RO load given the Bou-Ismail climate. Energy consumption in the case study under Bou-Ismail weather conditions were analyzed. The desalination of brackish water at a TDS value of 5 g/L requires an energy of about 1.5 kWh/m3. Using seawater at a TDS value of 35 g/L, this value increases to 5.6 kWh/m3. The results showed that the optimal recovery rate for system operation was determined to be 32% for a feedwater salinity of 35 g/L, and 80% for a feedwater salinity of 1 g/L.

Innovative desalination system driven by a solar micro gas turbine for off-grid applications

Past work by the authors has suggested that Solar micro Gas Turbines (SmGTs) can be used cost-effectively to produce electric power and heat for freshwater production through desalination, mainly in off-grid locations. This is further studied in this work, providing an exhaustive modelling procedure and methodology. Additionally, a comprehensive analysis of system performance under both design and part-load conditions is provided along with the complete set of characteristics of the components of the SmGT and the desalination unit. To this end, the SmGT is assessed first, incorporating innovative solutions that enable better off-design performance: Variable Inlet Guide Vanes (VIGVs) in the compressor and Variable Nozzle Guide Vanes (VNGVs) in the turbine. The implementation of these features brings significant advantages in part-load operation, leading to a considerable increase in solar-to-electric efficiency and rangeability, particularly under certain ambient conditions; in particular, using these features yields 5% higher efficiency at the minimum load of the original engine (without variable geometry) and, from this load setting downwards, 15% lower minimum stable load is enabled. Furthermore, a sensitivity analysis to control strategies and ambient conditions has been included, exploring their impact on system performance.The water treatment system is comprised of two elements. A Reverse Osmosis (RO) desalination unit is driven by the electric power produced by the SmGT. Considering the emphasis on flexibility and part-load operation enhancement addressed in this work, a moderate recovery rate is proposed for this unit. The RO unit produces brine with high salt concentration to be partially treated further in a Zero Liquid Discharge (ZLD) unit driven by the exhaust gases of the microturbine (at about 250–300 °C), where the sensible heat of this stream is harvested by the ZLD unit to “dry” and concentrate the effluent. Finally, the potential and the operational limitations of the ZLD system are discussed, complemented with results from an experimental proof of concept where the feasibility of the concept is verified.

Thermal modelling and analysis of a novel solar integrated waste-to-energy plant for sustainable society

Waste-to-energy incineration is an effective and sustainable solution to reduce produced waste and simultaneously generates electricity utilizing thermal energy. The waste-to-electrical efficiency of conventional incineration plants is limited to 20–25% due to the higher amount of moisture content in the feedstock and flue gas heat losses. In addition, tubes of the incineration boiler are subjected to corrosion problems at elevated temperatures. In the present research, a parabolic trough solar-integrated municipal solid waste power plant is proposed and thermodynamically evaluated for different useful outputs. The solar energy is harvested through parabolic trough collectors to reheat the working fluid of the incineration plant to increase the steam temperature before it is fed to the low-pressure turbine. Meanwhile, a single-effect absorption chiller is integrated to utilize the thermal energy of the trough collectors for cooling purposes. In addition, the thermal energy of flue gas is used to power an organic Rankine cycle that further drives a proton exchange membrane and reverse osmosis desalination unit for hydrogen and freshwater production, respectively. In this way, the steam temperature for reheating the low-pressure turbine is increased to further improve the performance of the proposed solar-integrated waste-to-energy plant without causing any corrosion problems to the incineration boiler. The integrated facility is thermodynamically analyzed based on a 560-tons/day incineration plant using the engineering equation solver (EES) software. The results indicate that the overall energy and exergy efficiencies of the proposed plant are 32.51% and 23.7%, respectively, while the coefficient of performance of the absorption chiller is 0.849. Moreover, it is concluded that the produced desalinated water and hydrogen rates are 23.96 kg/s and 0.000857 kg/s, respectively.

Techno-environmental assessment and machine learning-based optimization of a novel dual-source multi-generation energy system

The utilization of high-temperature hybrid energy systems has a vital and promising role in reducing environmental pollutants and coping with climate change. So, in the present research, a dual-source multigeneration energy system composed of a gas turbine, a supercritical carbon dioxide recompression Brayton cycle, an organic Rankine cycle, an absorption refrigeration system, and a reverse osmosis desalination unit is designed and analyzed from thermodynamic, environmental and economic perspectives. The system supplies power with a stable load to follow the changes in the demand side which is important for off-grid distributed energy systems. The dual-source operation of the system makes it possible to generate sustainable electricity leading to less utilization of fossil fuels in the gas turbine subsystem and reduction in environmental pollution, and furthermore, malfunctioning of a subsystem will not lead to the failure of the entire plant. Three multi-objective optimizations with different objective functions are accomplished using artificial neural network from data learning and genetic and Greywolf algorithms to obtain the best-operating conditions. Under the base conditions, for the total input energy of 699 MW to the entire system, the energy and exergy efficiencies, the unit exergy cost of products, the carbon dioxide emission index, and the payback period, respectively, were found to be 45 %, 54 %, 15.3 $/GJ, 112.2 kg/MWh, and 7.2 years. The net output power of the proposed system was calculated as 288.2 MW. A sensitivity analysis revealed that with a change in the pressure ratio of the supercritical carbon dioxide cycle, the net generated power and overall efficiency take maximum values of 293.9 MW while the unit exergy cost of products and carbon dioxide emission index take minimum values of 15.3 $/GJ and 110.1 kg/MWh, respectively. Furthermore, increasing the pressure ratio of the gas turbine leads to maximum values of 45 % and 54 % in overall energy and exergy efficiencies, respectively.

Energy behaviour and economic analysis of a photovoltaic-thermal (PV/T) collector coupled with a reverse osmosis (RO) desalination unit in Tunisian climatic conditions: a feasibility study.

Water scarcity affects about onebillion people in the world. Around two billion people could be living in water-stressed areas by 2050. For this reason, the desalination is always evolving due to the importance of the water resources found in the seas and brackish water. As these systems are generally energy intensive, the use of a renewable energy source is among the most appropriate solution. In this paper, both experimental and numerical investigations have been conducted to evaluate the performances and the economic viability of aphotovoltaic-thermal collector intended to supply a reverse osmosis (RO) unit. Experimental study is based on the input-output and dynamic system testing (DST)according to ISO 9459-5 standard method and computations use the energy and mass balances of the PV/T collector and the RO plant. Results of DST testing showed that the loss coefficient of the PV/T, the tank loss coefficient and the total tank heat capacity are 10.46 W.m-2.K-1, 1.596 W.K-1 and 388MJ.K-1, respectively. The ability to couple the RO technology to PV/T systems has been demonstrated. The complete system has been simulated for a water salinity of 10,000ppm and climatic data of Borj-Cedria (Tunisia) site (longitude 10° 25' 41″ E and latitude 36° 43' 04″ N). Numerical investigations showed that the electricity needs of a small off-grid desalination unit could be met by using a 6.48m2 PV/T panel surface area. In this case, the purified water produced has a salinity of 1500ppm and the flow rate is 24,000l/day. For a grid connected site, the produced and auxiliary powers are found to be equal to 54% and 21%, respectively. Moreover, the economic cost of adding a PV/T system into an existing RO unit has been evaluated and the results showed that the payback period is 6years.

Exergy-economic analysis and multi-objective optimization of a multi-generation system based on efficient waste heat recovery of combined wind turbine and compressed CO2 energy storage system

Due to the intermittent feature of renewable energies, their combination with energy storage systems seems efficient and profitable. In this regard, a wind turbine system is coupled with a compressed CO2 energy storage (CCES) system for multi-generation propose. This combination has not been done yet and seems very attractive and efficient with the present popularity of wind energy and energy storage systems. A fraction of the output power of the wind turbine is sent to the compressor and electric heater of the CCES layout in the charging and discharging period. In the CCES system, a thermoelectric generator (TEG 1), an absorption chiller, and a domestic hot water heat exchanger are used to waste energy elimination and the waste energy of the wind turbine is recovered by a trilateral cycle (TLC). The produced power of the TEG 1 and TLC is transmitted to a reverse osmosis desalination unit and an alkaline electrolyzer for freshwater and hydrogen production. Hence, the considered system is converted to a multi-product one. Energy, exergy, and exergy-economic (3E) studies are done on the whole layout through parametric analysis and multi-objective optimization. Exergy round trip efficiency and unit cost of products are obtained as 37.027% and 30.41 $/GJ in the optimization process. The considered system can produce 1960 kW of power, 336.1 kW of heating, 183.3 kW of cooling, 1.077 kg/s of freshwater, and 0.0138 kg/h of hydrogen in this case.

A transient simulation for a novel solar-geothermal cogeneration system with a selection of heat transfer fluids using thermodynamics analysis and ANN intelligent (AI) modeling

Today, due to the reduction of fossil resources and on the other hand the high environmental pollution of these resources, it is necessary to pay attention to alternative resources, including clean and available renewable resources. In this study, solar and geothermal energy sources are combined, generating electricity, cooling, freshwater, and hydrogen, along with selecting a suitable heat transfer fluid for parabolic trough solar collectors. This system consists of parabolic trough solar collectors, a steam Rankine cycle, a steam Rankine cycle with an organic Rankine cycle, a proton exchange membrane electrolyzer, and a reverse osmosis desalination unit. To analyze the performance of solar collectors, Therminol 59, Marlotherm SH, Syltherm 800, and Therminol VP1 heat transfer fluids are selected. Solar radiation intensity, solar collector mass flow rate, turbine and pump efficiency, evaporator pinch-point temperature, and organic Rankine cycle turbine inlet temperature were investigated as design parameters affecting system performance. Maximizing energy efficiency and reducing cost rate were selected as two objective functions and determined using a multi-objective sorting genetic algorithm (NSGA-II). The results showed that Therminol 59 has the highest energy efficiency and net power output compared to other heat transfer fluids. Also, the proposed system produces 1140 kW of electricity in the optimal state, and in the best state, it has an energy efficiency of 32.39% and a cost of 36.32 $/GJ.

Thermo-Economic Assessment of Photovoltaic/Thermal Pan-Els-Powered Reverse Osmosis Desalination Unit Combined with Preheating Using Geothermal Energy

Recently, the reverse osmosis (RO) process is widely used in the field of desalinating brackish water and seawater to produce freshwater, but the disadvantage of using this technology is the increase in the rates of electrical energy consumption necessary to manage these units. To reduce the rates of electrical energy consumption in RO desalination plants, geothermal energy and photovoltaic/thermal panels were used as preheating units to heat the feed water before entering RO desalination plants. The proposed system in this study consists of an RO desalination plant with an energy recovery device, photovoltaic/thermal panels, and a geothermal energy extraction unit. To evaluate the system performance, three incorporated models were studied and validated by previous experimental data. The results indicated that incorporating the geothermal energy and photovoltaic/thermal panels with the RO desalination plants has positive effects in terms of increasing productivity and reducing the rates of specific power consumption in RO desalination plants. The average saving in the specific power consumption for utilizing the thermal recovery system of PV panels and geothermal energy as preheating units reached 29.1% and 40.75% for the treatment of seawater and brackish water, respectively. Additionally, the economic feasibility showed the saving in the cost of freshwater produced from the RO desalination plants for incorporating both geothermal energy and photovoltaic panels with a thermal recovery system with reverse osmosis desalination plants of up to 39.6%.

Novel high-throughput screening platform identifies enzymes to tackle biofouling on reverse osmosis membranes

Biofouling is a ubiquitous problem in many industrial systems including reverse osmosis (RO) desalination units where the biofilm impedes the water flow. It is essential to develop novel cleaning methods that are non-damaging and environmentally friendly. The most promising cleaning agents are enzymes, which can selectively cleave the components that stabilize the biofilm. However, biofilm-degrading enzymes are often difficult to identify due to the unknown matrix composition and lack of effective screening methods. To overcome this, a flexible screening platform was developed to evaluate enzyme treatment on fouling removal directly on RO membranes. The developed platform was used to identify enzymes that could degrade biofilms on fouled RO membranes. The membrane biofilms were destabilized by a range of enzyme groups, most effectively by proteases, lipases, DNase, cellulolytic enzymes, and pectin-degrading enzymes. The most effective enzyme formulations could clean the membranes more effectively than conventional chemical cleaning agents, removing 45 % of the biofilm compared with 0 %–19 % for the chemicals (p ≤ 0.001), indicating that enzymes have the potential to replace or complement chemical cleaning. The screening platform thus proved a potent tool for systematically studying biofilms and could be applied to combat biofilms in many other applications.

Environmental/Economic assessment and multi-aspect optimization of a poly-generation system based on waste heat recovery of PEM fuel cells

In the present study, a novel poly-generation system is introduced and studied from energy, exergy, economic and exergy-economic standpoints. In the proposed configuration, the waste heat of proton exchange membrane (PEM) fuel cells is recuperated by an organic Rankine cycle (ORC). Also, an LNG subsystem is chosen as a heat sink medium for the ORC. In this study, the impact of system irreversibilities on the environment is considered as part of the exergoenvironmental analysis, which is a relatively new type of study. In the considered system, PEM fuel cells are responsible for output power while the output power of the ORC and LNG subsystem is transmitted to a trans-critical CO2 compression refrigeration subsystem and a reverse osmosis desalination unit for cooling and freshwater production. A sensitivity analysis is done to assess the effect of changes in PEM fuel cells temperature, PEM fuel cells pressure, current density, and condensation temperature of ORC on the output parameters. Considering the just-mentioned parameters as design variables, the results of two-objective optimization reveals that the exergy efficiency and net present value are calculated to be 22.67 % and 56.61 M$, correspondingly. At the optimum point, the proposed system can produce 1214 kW power, 1116 kW cooling, 161.1 kW heating, and 6 kg/s freshwater. Also, exergoenvironmental index and sustainability index were obtained as 0.5472 and 2.256 at the optimum point.

Exergoeconomic and optimization study of a solar and wind-driven plant employing machine learning approaches; a case study of Las Vegas city

High reliance on conventional fuels and existing freshwater resources is unviable in the long run. A multi-generation system primed with a parabolic trough solar collector and a wind turbine is introduced in parallel to the efforts to shift this dependency on alternative fuels. A thermoelectric generator was integrated with the steam Rankine cycle as a condenser for higher electricity generation. The steam Rankine cycle, a wind turbine, a reverse osmosis desalination unit, and a single-effect absorption chiller, and proton exchange membrane electrolyzer were employed for freshwater, cooling load, and hydrogen production. The performance of several thermal oils was analyzed based on the first and second laws of thermodynamics, and Syltherm 800 was chosen as the best option. The artificial neural network-based model was considered to remodel the thermodynamic issues in the second section. The multi-aspect grey wolf optimization approach was carried out to find the optimum conditions of the target functions. According to the results, solar part (901.4 kW) has the highest exergy destruction value. Consequently, in a case study that considered the conditions of Las Vegas city, 22.02 MWh power and 4.50 tons CO2 per year were achieved, which leads to an environmental cost of 107.8 $/year, equivalent to the cost of expansion of 218.2 m2 of farm or green zone.

Nuclear-Powered Reverse Osmosis Desalination Unit Performance Improvement Using Six Sigma and Desalination Economic Evaluation Model

Nuclear-Powered Reverse Osmosis Desalination Unit Performance Improvement Using Six Sigma and Desalination Economic Evaluation Model