Energy analysis and efficiency assessment of reverse osmosis desalination process

Systematic Analysis Reveals Thermal Separations Are Not Necessarily Most Energy Intensive

Aim. The work aimed to develop and test an integrated multi-level model using the Northwestern Federal District (NWFD) as an example, confirming the stimulating effect of energy efficiency improvements on the region’s socioeconomic development rates. Objectives. The work seeks to conduct a quantitative analysis of energy efficiency in the regional economy using the proposed integrated multi-level model and identify challenges in improving it in the NWFD regions; calculate an integrated energy efficiency index; and develop a typology of regions and clusters based on energy efficiency. Methods. The methodological background is based on the scientific principles of modeling theory, regional development theory, and economic system management, presented in the works of prominent Russian and international scientists. These were applied for the development of an integrated multi-level energy efficiency assessment model that integrates economic, environmental, and social parameters. This model provides a comprehensive approach to energy efficiency assessment and is used to develop strategies aimed at minimizing negative environmental impacts and improving the quality of life of the population. The author of this article applied economic modeling and integrated assessment methods, as well as regression, cluster, and index analysis. Results. Testing the proposed integrated multi-level model using the NWFD regions as an example enabled to conduct a study of energy efficiency in the regional economy, identify challenges in improving it across regions, as well as substantiate indicators for calculating and defining an integrated energy efficiency index. Based on this index, a typology and cluster groups of the NWFD regions were developed. This methodological framework, which provides a comprehensive approach to analyzing and assessing energy efficiency in regional economic systems, takes into account the unique socioeconomic and natural conditions of each region. Conclusions. The territorially differentiated approach underlying the proposed modeling is aimed at creating a tool that ensures the relevance of energy situation assessments in each region, thereby facilitating the development of targeted strategies to improve energy efficiency and quality of life in the NWFD regions. The study confirms the need for an integrated approach to energy efficiency analysis and assessment, which combined economic and mathematical modeling, systems analysis, and a territorially differentiated approach. This enables the development of strategic measures that help adapt to changing conditions and ensure the long-term socioeconomic development of the NWFD and other regions of Russia.

This paper present energy and exergy analysis of the main marine steam turbine, which is used for the commercial LNG (Liquefied Natural Gas) carrier propulsion, at four different loads. Energy analysis is performed by using four different methods. The presented analysis allows distinguishing advantages and disadvantages of all observed energy analysis methods and its comparison to exergy analysis of the same steam turbine. Each analysis is based on the measurement results obtained in main turbine exploitation conditions. Main turbine is composed of two cylinders – High Pressure Cylinder (HPC) and Low Pressure Cylinder (LPC). At low turbine loads, the dominant power producer is HPC, while at middle and high loads the dominant power producer is LPC. Energy analysis Method 1 which is based on the same principles as exergy analysis, should be avoided if the majority of turbine losses are not known. Other observed energy analysis methods can be applied in the analysis of any steam turbine, with a note that increase in ideal (isentropic) steam expansion process divisions will result with an increase in energy losses and with a decrease in energy efficiency. Energy analysis Method 2 which consist of only one ideal (isentropic) steam expansion process, for the whole turbine and at all observed loads, results with the lowest energy losses (in the range between 639.98 kW and 6434.17 kW) as well as with the highest energy efficiency (in a range between 53.70% and 79.40%) in comparison to other applicable energy analysis methods. For the observed loads, whole main turbine exergy destruction is in range from 608.64 kW to 5922.86 kW, while the exergy efficiency range of the whole turbine is between 54.94% and 80.73%. Exergy analysis and all three applicable energy analysis methods show that increase in the main turbine load results with simultaneous increase in turbine losses and efficiencies (both energy and exergy).

The article is devoted to consideration of issues related to assessing the energy efficiency of a coal mining enterprise. Coal mining enterprises are characterized by a large volume of energy intensive ore mining operations. The article presents possible ways of energy saving in the mining industry. During the research, a system of energy efficiency indicators for coal mining enterprises is presented. Materials and methods. The article proposes a system of indicators for coal enterprises based on existing methods and approaches to assessing energy efficiency. Energy consumption dependence graphs, benchmarking, and pinch analysis are considered as a starting point. Results. The study presents a system of energy efficiency indicators for coal mining enterprises. The proposed system has several levels. The existing methods and approaches for assessing this important indicator for industrial enterprises in the coal industry as a whole are considered. The author’s approach to formalizing the system of energy efficiency indicators for coal mining enterprises is proposed. The significance of energy audit as a key assessment measure is indicated and its stages are highlighted. The influencing factors determining energy costs and their reduction for a coal mining enterprise are systematized, barriers preventing the practical implementation of energy saving measures are analyzed. Discussion. The proposed metrics system provides a comprehensive framework for assessing the energy efficiency of coal mining enterprises at various levels. Its flexibility allows it to be applied to the analysis of individual equipment units, production processes, and overall enterprise performance. Its multi-level approach provides a detailed understanding of energy consumption, which allows for informed decision-making to optimize operations. At the equipment level, the metrics system evaluates the energy consumption and efficiency of individual machines and devices. At the production process level, the metrics system analyzes the energy consumption and efficiency of various stages of coal mining. At the enterprise level, the metrics system provides a comprehensive assessment of overall energy efficiency. It takes into account energy consumption at all levels and allows enterprises to compare their performance with each other and with industry benchmarks. Conclusion. Energy efficiency assessment of a coal mining enterprise allows to understand how and where energy is used, where its use can be improved, and how to reduce its costs. To conduct an energy efficiency assessment, the article proposes a system of indicators, highlighting the features of an energy audit. The main advantage of the proposed system of indicators is that it covers a wide range of energy consumption indicators, which are carefully selected and located at different levels of detail. In general, a balanced approach to the level of detail and generalization in the system of indicators provides flexibility in adapting indicators to specific research questions and helps to interpret the results in the context of structural differences between energy systems. Resume. Overall, the proposed metrics system offers a comprehensive approach to analyzing the energy efficiency of coal mining enterprises, covering all levels of operations. Its use allows enterprises to improve energy efficiency, reduce operating costs, and contribute to a more sustainable coal mining industry. Suggestions for practical applications and directions for future research. The use and implementation of the developed system at a coal mining company allows it to improve energy efficiency, reduce operating costs and contribute to a more sustainable coal mining industry.

For ambulatory children with cerebral palsy, the assessment of walking energy efficiency is utilized to determine functional changes following surgical, pharmacologic, or orthotic interventions. While the assessment of energy efficiency is considered a useful outcome tool, minimal information exists about the changes in energy efficiency over one year in children with cerebral palsy at different gross motor function classification system (GMFCS) levels and whether the patterns of change are similar to their able-bodied peers. The purpose of this study was to determine whether energy efficiency variables change similarly over one year in children with cerebral palsy by GMFCS level and whether they differ from their age-matched peers. Forty-five able-bodied children and 34 children with cerebral palsy, GMFCS levels I-III participated in the study. Energy efficiency variables were measured at baseline and at 12 months using a Cosmed K4b2. All subjects walked at their self-selected velocity for testing around a 33 m track. Baseline velocity and net non-dimensional cost (NNcost) differed by GMFCS level and between the able-bodied peers and all GMFCS levels. Children in GMFCS level III had the highest cost and the slowest velocity. When controlling for age and baseline values, significant differences in the magnitude of change were seen in velocity between children in GMFCS level III and children in GMFCS level I and II and their able-bodied peers. In comparison to their able-bodied peers, all GMFCS levels had an increase in NNcost over one year when controlling for age and baseline NNcost, with the difference in magnitude increasing by GMFCS level. Consistent with the literature, children with cerebral palsy had an increase in NNcost over one year in comparison to their able-bodied peers, which increased with GMFCS level. This finding demonstrates that when evaluating the change in walking energy efficiency with maturation and therapeutic intervention, comparisons should be made by GMFCS level.

Energy-efficient resin wafer electrodeionization for impaired water reclamation

In light of the water and energy crises around the world in general and Libya in particular, and the constant endeavor to provide visions and solutions to resolve these crises. This study is one of the efforts to contribute to this topic, as the study aims to increase the efficiency of a desalination plant that operates with gas turbines. The study aims to increase the efficiency of the total plant (the desalination plant that operates with turbines) by using part of the exhaust gas resulting from operating the turbines in the presence of a combined cycle. The study also aims to clarify how this can be applied to raise the efficiency of the total station, taking into account achieving the highest efficiency, the lowest cost rate, and the lowest environmental pollution rate while maintaining the default for the station. This was done through different methodologies, as the descriptive method was used. To describe the variables and data, the quantitative and scientific methodology in collecting data, determining the applied framework, and the comparison methodology in comparing the results. The analysis methodology was also used to analyze and evaluate the results. The results indicated that the best way to raise the station's overall efficiency is to use the combined cycle with a higher percentage of exhaust gas. The obtained efficiency is 34.5%, with a total cost of 20% and an emissions rate of 35%, while maintaining the plant's life span as 35% of the exhaust gas was used. Keywords: desalination plant; Gas turbines; exhaustive Gas; combined cycle; efficiency; pollution rate; life Span.

The desalination technology of choice today is reverse osmosis (RO). In this process saline water is forced using mechanical pressure across a membrane that can selectively pass water and reject almost all ions and most neutral molecules. Reverse osmosis proved to be robust and most energy efficient technology that can be exploited for a wide range of water sources. Nevertheless water desalination is still an energy intensive process. Theoretical calculations show that the minimum required energy for seawater desalination is about 1 kW hr m-3, whereas the most energy optimized plants require 2-4 kWh m-3, suggesting that there is much room for improving the membranes performance and energy efficiency (Shannon et al. 2008). Despite the numerous improvements the RO membranes have gone through over the last 5 decades, they are still inferior to cell membranes both in terms of permeability and, especially, selectivity. The fast and selective water transport in biological membranes is achieved by means of aquaporins, specialized trance-membrane proteins. The osmotic water permeability of aquaporins was shown to be in the range of 6×10-14 11×10-14 cm3 sec-1 channel-1 for AQP1 (Saparov et al. 2001) and their ion rejection exceeds by far the ion rejection of the most advanced commercial membranes. Estimates show that a biomimetic lipid bilayer with incorporated aquaporins with a lipids to protein ratio (LPR) of 50, would yield a membrane with a hydraulic permeability of ~9 – 16.5 L m-2 hr-1 bar-1 whereas the permeability of seawater RO membrane does not exceed 2 L m-2 hr-1 bar-1 (Kaufman, Berman & Freger 2010). Biological membranes are also known to reject small molecules, such as urea or boric acid, which are poorly removed by commercial membranes (Borgnia et al. 1999). The combination of ultra-selectivity with extremely high water permeability makes biomimetic membranes highly attractive for water purification applications. It is important to emphasize that water transport through biological membranes, usually existing as microscopic free-standing self-supporting structures, is usually driven by electrochemical potential gradients, i.e. osmotic pressure or electric field (Tanaka, Sackmann 2005). However, for practical membrane applications, such as water purification, the use of hydraulic pressure as a driving force and planar membranes of macroscopic dimensions, the common configuration in membrane technology, will be far more preferable. However, the preparation of such biomimetic membranes poses a number of challenging questions, such as: how can one prepare a large and defect-free biomimetic planar membrane? can they be made to withstand hydraulic pressures? how can aquaporins be incorporated in such membranes? will aquaporins keep their activity under a hydraulic pressure gradient?

Optimizing solarized desalination unit through the implementation of 4-step MED method using energy, exergy, economic and environmental analysis

Sustainable, inexhaustible, economical, and clean energy has become a vital prerequisite to replace fossil fuel sources for power production. In such a context, countries like Pakistan, which are heavily skewed towards fossil fuel-fired plants, are diverting attention to install more and more indigenous renewable energy sources projects such as solar-photovoltaic and wind turbine power plants. In order to harness the maximum energy of wind turbines, it is crucial to factually and precisely assess system performance, which is traditionally inferred by energy analysis (first law analysis). Nevertheless, this analysis only computes the nominal power generation output and ignores the effect of meteorological variables that can lead to some serious errors during the energy planning phase. Consequently, this case study presents both the energy and exergy analysis of a wind farm located in Gharo town of Thatta District along the coastline of the Indus Delta. Energy analysis is carried out to quantify energy efficiency, while exergy analysis computes exergy efficiency by taking into account the effect of pressure, temperature, and wind speed. Comparisons of both efficiencies are provided, and the result substantiates that exergy efficiency turns out to be lower than energy efficiency. However, exergy is a more viable index due to the inclusion of exergy destruction, and in comparison to the energy indicator, it presents the actual performance of a thermodynamic system. The monthly energy and exergy efficiency of the general electric wind turbines are maximum in July having values of 0.5 and 0.41, respectively.

With the increase in the world population and industrialization, the use of water resources for industry and domestic needs is also increasing. At the same time, the impact of the water sector on climate change is increasing due to emissions of greenhouse gases associated with the energy processes of water production, transportation and purification. Given that efforts aimed at mitigating the consequences of climate change are not enough today, it is very important to develop new ambitious strategies for sustainable development and decarbonization. The purpose of the work is a mathematical study of the air humidification-dehumidification cycle to obtain fresh water and the search for optimal parameters that will ensure the maximum efficiency of the desalination process. The principle of operation was considered and a mathematical model of the thermal water desalination system with air heating at the entrance to the humidifier in the solar heater was developed. A comprehensive thermodynamic analysis of the proposed scheme was made. The temperatures of air and salt water at the outlet of the heat exchangers were determined. The main energy parameters of the system were calculated with the help of balance equations. Graphical dependences of energy indicators on the operating parameters of the installation were constructed and analyzed. The change in performance and energy efficiency as a function of temperature and air velocity at the inlet to the humidifier is shown. The effect of air and salt water consumption on the energy efficiency and geometric dimensions of the humidifier was revealed. A comparison of the efficiency of open water desalination schemes with heating of air and water at the entrance to the humidifier is given. It was established that, under the same conditions, water heating provides higher energy parameters than air heating. The expediency of simultaneous heating of water and air at the entrance to the humidifier to further increase the efficiency of thermal desalination using the air humidification-dehumidification cycle was noted.

Li, Z. and Liu, Y., 2019. An improved model for marine energy price and efficiency assessment. In: Gong, D.; Zhu, H., and Liu, R. (eds.), Selected Topics in Coastal Research: Engineering, Industry, Economy, and Sustainable Development. Journal of Coastal Research, Special Issue No. 94, pp. 640–647. Coconut Creek (Florida), ISSN 0749-0208.It's generally known that ocean stores abundant energy resources for the development and growth of human beings. Nowadays, the sustainable development of marine economy calls for precisely speculation of marine energy prices and efficiency. However, the traditional methods of measuring energy price and efficiency, for instance, the EROI (energy return on investment) model unable to define system boundaries and to calculate labor and physical costs, be it tidal energy or marine biomass energy. Thus, these methods may ignore as much as 50% of input energy consumption. Energy efficiency could be calculated by the ratio of average energy input cost to the average useable energy output cost while energy price could be measured by the ratio of the monetary input to the output. The principle above could be viewed as a check for energy return on investment as well as an elimination for a redundant process analysis. The results give us a chance to innovate traditional energy efficiency model by social and environmental factors which could be depicted through monetary terms. The precise estimation of marine energy efficiency could also help us make appropriate policies to combat global warming.

Surfaces with efficient photothermal conversion have great value in both science and industry. In this study, large-area hierarchical microstructures and nanostructures with high light absorptance over a wide spectrum range from ultraviolet to the near-infrared region were fabricated on copper surfaces by a low-cost green nanosecond laser system. By optimizing the morphology of laser-induced surface structures, the average light absorptance in the wavelength range of 220–800 nm and 220–2500 nm can be as high as 98.9% and 91.9%, respectively. Moreover, the laser-processed surfaces demonstrated a photothermal conversion efficiency of more than 52% under 15 sun illuminations. The authors also showed that the desalination efficiency was greatly improved when the prepared surfaces were used as the solar energy harvesting surfaces in the solar energy driven desalination system.Surfaces with efficient photothermal conversion have great value in both science and industry. In this study, large-area hierarchical microstructures and nanostructures with high light absorptance over a wide spectrum range from ultraviolet to the near-infrared region were fabricated on copper surfaces by a low-cost green nanosecond laser system. By optimizing the morphology of laser-induced surface structures, the average light absorptance in the wavelength range of 220–800 nm and 220–2500 nm can be as high as 98.9% and 91.9%, respectively. Moreover, the laser-processed surfaces demonstrated a photothermal conversion efficiency of more than 52% under 15 sun illuminations. The authors also showed that the desalination efficiency was greatly improved when the prepared surfaces were used as the solar energy harvesting surfaces in the solar energy driven desalination system.

Energy is most precious thing, so it can be used most efficiency way. Most types of energy now a day's use in form of electricity, which is mainly generated in steam power plant and rest of source are wind, hydro and solar. The heart of steam power plant is boiler and to maximize efficiency of power plant, there is need to increase efficiency of boiler. The boiler efficiency can be evaluated by direct and indirect method, in direct method the energy gain by working fluid is compared with energy content of fuel while in case indirect method various losses compared to the energy input. Present work is concern on energy analysis and efficiency assessment of water tube boiler for sugar industry. By using catalyst what kind of effect on exhaust gas, combustion quality, environment friendliness, economy and up to what extent efficiency increase. By increasing boiler efficiency one can save fuel input to power plant and also earn carbon point and can increase profit to plant. From considering overall analysis and results it is concluded that, the pre boiler efficiency measured by O2 gas analyzer remains same as defined value without using solid combustion catalyst. It also shows that the efficiency of the pre-boiler leads to increase of the order of 2.82%, 2.86%, 2.35% and 2.4% related to four different observed boilers with use of solid combustion catalyst, which is more supportive and required for the reduction of cost. The overall 2.61% improvement in the boiler efficiency as well as 3.3% reduction in baggase consumption. The overall saving of rupees 41, 19,000 with this efficiency is done after using the catalyst.

Design and techno-economic evaluation of multi-stage membrane processes for helium recovery from natural gas