•Review of methods used for heat integration of Organic Rankine Cycle.•Integration of Organic Rankine Cycle with industrial waste heat.•Influence of working fluid selection, architecture and low ...temperature waste heat.•Problems in integration with continuous and batch industrial processes.
Production systems represent a significant source of waste heat. The waste heat cannot be reused often. Many optimization methods can give a solution for waste heat recovery. However, the results do not depend only on the method. The low-temperature waste heat makes difficulties for its recovery within the processes. Organic Rankine Cycle units can be used for low-temperature heat transformation into electricity. Linking the Organic Rankine Cycle within the heat integrated system is not simple. This depends on the influence of a few important factors. The process parameters of the working medium, the physical and chemical characteristics of the working fluid, the continuity of heat supply, and the temperature level of waste heat are necessary conditions that must be included in optimization. The optimization method should determine the optimal operating point of the Organic Rankine Cycle. The displacement of the operating point leads to decrease in the effective transformation of heat into electricity. These problems are analyzed through a review of the methods and approaches used for the integration of Organic Rankine Cycle in thermal process systems. These include Pinch technology, Non-Linear Programming, Multiple Integer Linear Programming, Genetic Algorithm, Artificial Neural Network and many different approaches for polygeneration systems. All methods were compared and systematized in a general scheme for integration of an Organic Rankine Cycle with low-temperature industrial waste heat supply. This work also includes experience in implemented and designed projects of an integrated Organic Rankine Cycle.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Following the 2015 Paris Agreement and other agreements which have been signed after, sustainable energy development is becoming the major goal in many countries. EU have set the targets to reduce ...the annual greenhouse gas emission by 40% in 2030 and 80% for 2050 compared with 1990 levels. For achieving this ambitious energy policy, three major technological changes are available: energy savings on the demand side, efficiency improvements in the energy production, and replacement of fossil fuels by various sources of renewable energy. Also, for realization cited three major technological changes the support of the multi-disciplinary scientific knowledge is needed. Therefore, from the beginning of the 21st century, since 2002, a series of Sustainable Development of Energy, Water and Environment Systems (SDEWES) Conferences were founded. This paper presents an overview of published researches in special issues of leading journals dedicated to the series SDEWES Conferences, including also the papers in current special issue. The focus is on five main fields: (1) energy policy and analysis of smart energy systems; (2) energy savings in the building sector; (3) co/polygeneration - integrated heating, cooling and electricity systems and district heating; (4) biomass for energy; and (5) measurement of energo-environmental sustainability of processes and systems. Researchers are focused on the development of methods, policies and technologies for both efficient production of energy, mainly from renewable sources, and consumption in industry, buildings and transport. Undoubtedly, the researches presented in the papers in this special issue as well as in previous ones, dedicated to SDEWES conferences, will contribute to the promotion of sustainable development and thus to the achievement of the goals of the Paris Agreement.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Today, coal is responsible for 40% of annual CO2 emissions. At the same time, global warming causes climate changes accompanied with catastrophic meteorological phenomena all over the world. After ...the 2015 Paris Agriment many countries set ambitious energy policy to reduce the annual greenhouse gas emission. The 2021 UN Climate Change Conference, COP26 - Glasgow, ended with the adoption of a less stringent resolution than some anticipated: countries only agreed to “phase down” rather than “phase out” coal. Is possible the realization of the Paris Agreement after COP-26? For achieving this ambitious targets in such conditions, the support of the multi-disciplinary scientific knowledge is needed. Since 2002 a series of SDEWES Conferences were founded. This paper presents an overview of published researches in special issues of leading journals dedicated to the series SDEWES Conferences, including also the papers in current special issue presented on Conferences held in 2020: 2nd LA SDEWES Conference - Buenos Aires, 1st AP SDEWES Conference - Gold Coast, 4th SEE SDEWES Conference - Sarajevo and 15th SDEWES Conference - Cologne. The focus is on five main fields: (1) energy system analysis; (2) energy savings in the building sector; (3) district heating; (4) electrification of transport and (5) water-energy nexus. Undoubtedly, the researches presented in this special issue as well as in previous ones, will contribute to the achievement of the goals of the Paris Agreement in difficult conditions after COP26.
•Sustainability concept of energy, water and environment systems becomes an unavoidable issue.•SDEWES Conferences are one of the most relevant in the world in its field.•RES, DH and EV represents a promising strategies to achieve a carbon neutral society.•The zero CO2 buildings (green buildings) can help in solution of climate crisis.•Water-energy nexus is important due to increasing energy demands and decreasing freshwater.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Ever since 2002, when the first Conference on Sustainable Development of Energy, Water and Environment Systems (SDEWES) was held in Dubrovnik, the SDEWES conferences series has been providing a forum ...for world-wide scientists and those interested in learning about the sustainability of development, to present research progress and to discuss the state of the art, the future directions and priorities in the various areas of sustainable development. One of the main issues of the coming decades is to improve efficiencies by integrating various energy systems, using excess from one, as resource in another in the correct moment. Integrating electricity, heating, cooling, transport, water, buildings, waste, wastewater, industry, forestry and agriculture systems will be pivotal towards sustainable development. SDEWES has maintained high publishing standard as 2408 SDEWES papers were published in special issues of leading scientific journals including “Energy - The International Journal”. In 2022, the 17th SDEWES Conference was held during November 6–10 in Paphos, Cyprus, the 5th SEE Conference took place in May 22–26, 2022 in Vlorë, Albania, the 3rd Latin American Conference was held through a virtual platform during July 24–28, 2022. The Energy journal has continued its cooperation with SDEWES launching a special issue dedicated to the 2022 Conferences. The special issue includes papers which traditionally cover a range of energy issues - higher renewables penetration and various technologies and fuels assessments at energy supply side, as well as, energy efficiency in various sectors, buildings, district heating, electric vehicles and demand modelling at energy demand side.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Design methods and concepts that can increase the energy conversion efficiency of marine and river current turbines are of great importance for the development and wider utilization of this emerging ...renewable energy technology. This work is aimed to improve hydrodynamic performances of the hydrokinetic turbines to get as close as possible to the theoretical energy conversion efficiency limitation of 59.3%, known as the Lanchester–Betz–Joukowsky limit. The winglets are integrated at the turbine blade tips to reduce the effect of the tip vortex. The winglet design concept is adopted from the jet aircraft and adjusted to the hydrokinetic turbine application. The numerical investigation of the winglets impact on the hydrodynamic performances was performed using computational fluid dynamic (CFD). The results indicate that winglets subdue the strength of tip vortices, which is reflected through the increase in the power extracted. It has been confirmed that winglet height has a great influence on the power coefficient increase, which for higher winglets reaches the value above 50%. The analysis of the wake regions behind turbines pointed out that the turbines with winglets form stronger vortices in the far wake zone which may influence the back-flow turbine installed in row array.
•Increase of maximum power coefficient up to 13% at design tip speed ratio.•Energy extraction improvements are achieved with higher winglets.•Blade tip losses reduction are obtained by diffusing tip vortices.•The detailed analysis of the flow around hydrokinetic turbines with winglets is performed.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Although several problems related to biofouling of marine current turbines (MCTs) are reported in the literature, the most important one is related to long-term operational performance and ...maintenance costs. Nevertheless, studies related to the impact of biofouling on MCT performance are rather scarce. In this study, the impact of biofilm on MCT performance is investigated using the Computational Fluid Dynamics (CFD) approach. Biofilm is modelled using previously developed roughness functions implemented in a wall function solver. A verification study is performed to determine sufficient grid spacings and to calculate numerical uncertainty. The validation study is conducted by comparing the obtained results with experimental and numerical ones from the literature. Full-scale CFD simulations are performed for six fouling conditions with varying biofilm height and percentage of surface coverage at eight tip speed ratios (TSRs). The obtained results highlight the significant impact of biofilm on MCT performance reflected in a decrease in the power coefficient, which for the optimal TSR is equal to −10.7% for the R1 fouling condition. Finally, a detailed analysis of the flow around MCTs fouled with biofilm is conducted and the reasons for the detrimental impact of biofilm on MCT performance are discussed.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Horizontal axis turbines are commonly used for harnessing renewable hydrokinetic energy, contained in marine and river currents. In order to encourage the expansion of electricity generation using ...micro-hydrokinetic turbines, several design improvements are investigated. Firstly, optimization-based design of rotor blade is used to get as close as possible to the efficiency limit of 59.3% (known as Betz limit), that counts for bare turbine rotors, placed in the free flow. Additional diffuser elements are further added to examine the potential to overcome the theoretical efficiency limit by accelerating water at the axial direction. Various diffuser geometrical configurations are investigated using the computational fluid dynamics (CFD) to obtain insight into hydrodynamics of augmented micro-hydrokinetic turbines. Moreover, the turbines are compared from the energy conversion efficiency point of view. The highest maximum power coefficient increase of 81% is obtained with brimmed (flanged) diffuser. Diffusers with foil-shaped cross-sections have also been analyzed but power augmentation is not significantly greater than in the case of simple cross-section designs of the same dimensions. The power coefficients’ comparison indicate that considerable power augmentation is achievable using brimmed diffuser with higher value of length-to-diameter ratio. However, the impact of diffuser length increase on the power coefficient enhancement becomes weaker as the length-to-diameter ratio reaches a value of 1.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The environmental impact of the energy sector and the security and economics of energy supply and utilisation have been raising increasing concerns, stimulating the search for innovative solutions ...for a sustainable use of resources. This article provides an overview of published research in this area, with a focus on papers contributed in special issues of leading journals dedicated to the series of Conferences on Sustainable Development of Energy, Water and Environment Systems (SDEWES), including the articles in the current special issue. Based on this review, research trends are identified and achievements supporting the energy transition are highlighted. The studies that focused on regional or urban energy planning have aimed at (a) increasing penetration of renewable energy sources, (b) optimizing the mix of centralized and distributed technologies (c) introducing additional flexibility in the power sector and (d) identifying solutions for sustainable heating. Conversely, researches focused on single plants or users have targeted the development of technologies for efficient energy use in industry and buildings, with emphasis on multi-generation and waste heat utilisation. The review highlights that future scenarios based on sustainable energy systems are viable, although their implementation will require further efforts by researchers and investors and active involvement of consumers.
•Research trends on energy transition and the associated technologies are reviewed.•Literature review examined the Special Issues of journals dedicated to SDEWES Conferences.•Challenges posed by increased share of renewables are solvable by cost-efficient solutions.•Power-to-heat and district heating are key-technologies for sustainable energy supply.•Energy saving in the building and industrial sectors contributes to sustainability of energy sector.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
In the Republic of Croatia there is some medium temperature geothermal fields (between 100 and 180 °C) by means of which it is possible to produce electricity. However, only recently concrete ...initiatives for the construction of geothermal power plants have been started. In previous papers, the possible cycles for geothermal fields in the Republic of Croatia are proposed: ORC (Organic Rankine Cycle) and Kalina cycle. Also for the most prospective geothermal fields, energy and exergy analysis for the proposed cycles are performed, on the basis of which the most suitable cycle is proposed. It is ORC which in all cases has better both the thermal efficiency (the First Law efficiency) and the exergy efficiency (the Second Law efficiency). With aim to further improving of geothermal energy utilization in this paper the replacement of a basic ORC with a dual-pressure ORC is analysed. A dual-pressure cycle reduces the thermodynamic losses incurred in the geothermal water-working fluid heat exchangers of the basic ORC, which arise through the heat transfer process across a large temperature difference. The dual-pressure cycle maintains a closer match between the geothermal water cooling curve and the working fluid heating/boiling curve and these losses can be reduced. Now, on the example of the most prospective geothermal field, Velika Ciglena (175 °C), energy and exergy analysis for the proposed the dual-pressure cycle are performed. As a conclusion, in case of Geothermal Power Plant Velika Ciglena, a dual-pressure ORC has slightly lower thermal efficiency (13.96% vs. 14.1%) but considerably higher both exergy efficiency (65% vs. 52%) and net power (6371 kW vs. 5270 kW).
•In Croatia there are several medium temperature geothermal sources (100–180 °C).•Electricity production is possible in binary plants with ORC (Organic Rankine Cycle) or with the Kalina cycle.•In all cases ORC has better thermodynamic characteristics than Kalina cycle.•The replacement of a basic ORC with a dual-pressure ORC is analysed.•A dual-pressure ORC achieves higher net power.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
PDF
