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Plastic debris has been a consistent issue in the global environment, and plastic waste recycling is the most promising option to avoid further accumulation. The waste quality serves as a crucial restriction for recycling planning and requires proper definition. This work aims to extend the previously developed data-driven approach to quantifying the recyclability clusters of plastic waste to consider polymer heterogeneity in the evaluation. Heterogeneity estimation is conducted by identifying the compatibility between polymers based on their surface tension. The applicability of the polymers mix (targeted and non-targeted polymers) can then be decided based on the Q-value approach. The method identifies the quality class of the plastic mixture based solely on the compatibility of the polymer, where the quality trend varies for each identified compatibility class. This gives insights into the suitability of mixing different polymers type prior to recycling. The recycling potential/circularity of the plastic waste can then be identified based on the Plastic Pinch Analysis, which outputs the ideal maximum external plastic demands with a certain threshold grade of the plastic (Pinch Quality). A case study is shown using three types of polymers: Polyethylene Terephthalate (PET), Polyethylene (PE) and Polypropylene (PP), to showcase the polymers heterogeneity evaluation. The results show that around 32.4 % of disposed PP waste could potentially be mixed with PE to have a compatible mixture. However, it is also crucial to check the properties of the mixed polymers to fulfil the demands of site requirements prior to recycling. [ABSTRACT FROM AUTHOR]

The opportunistic maintenance (OM) approach allows exploiting the stoppage for performing additional maintenance actions alongside those planned, to save cost and time. This study aims to propose a graphical approach to identify the optimal maintenance grouping strategies in an operating process. The failure of a specific component is predicted by using the statistically-derived probability distribution function that reflects its time-variant failure behaviours. The periodic maintenance schedule is first derived, and the system failure likelihood is predicted within each time interval. The failure of one of the component creates an opportunity to reschedule maintenance activities, which can be carried out while replacing the failed components. The expected cost to mitigate the failures ('Sinks') can be reduced by the expected maintenance reschedule cost savings ('Sources') based on the derived schedule previously. In this work, Pinch Analysis is used as a targeting tool to determine the maximum cost savings and expected cost required to handle unexpected plant shutdown. The methodology is presented and demonstrated with a case study, featuring the component replacement for a hydrogen compressor in an oil refinery. The results show that about 35% of the expected failure cost would need to be invested for opportunistic maintenance at the earlier time, minimising the risk of failure, while the remaining 65%can be saved. The extra savings at the end of the period also suggest the maintenance grouping can be further reduced. The limitations and potential future development of the framework are discussed as well. [ABSTRACT FROM AUTHOR]

Waste recovery and disposal are one of the biggest management challenges. An adequate waste management design is critical in contributing to the development of a sustainable circular economy. There is a need for a systematic and preferably graphical approach to assessing the emissions associated with waste treatment processes followed by strategies for mitigation. This study aims to propose a graphical approach in identifying the appropriate waste management system (WMS) with lower emissions. The proposed graphbased approach termed as Extended-Waste Management Pinch Analysis (E-WAMPA) is an extension to the existing WAMPA. It is distinguishable by three major issues a) Emission intensity of WMS (Net GHG per capita) and stagewise algorithm aims for regional waste management planning are introduced, b) the emissions of recycling are not assumed as zero c) The demonstration is based on the defined targets, projection and power grid mix of EU. A generic methodology of E-WAMPA is presented and followed by the European Union- 28 member states (EU-28) case study to elucidate the application. The considered waste type is the municipal solid waste (MSW), and the assessed emission is GHG. E-WAMPA is capable of suggesting the strategies in fulfilling the targeted emission reduction of a region (e.g. 10% reduction) and meeting the individual treatment targets. One of the possible strategies is demonstrated on adjusting the WMS of Malta, Greece, Cyprus and Romania. The way forward of E-WAMPA have been discussed as well. [ABSTRACT FROM AUTHOR]

Abstract The emergence of Pinch Analysis from more than four decades ago opened a new area of intense research development that has even accelerated in recent years. Initially, Pinch Analysis (PA) provided a systematic thermodynamic-based approach to address the need for large energy savings around the 1970s oil crises. Since inception, the Pinch Methodology (PM) has flourished considerably, finding meaningful application to a wide range of industrial, regional, and global challenges well beyond heat – it's most well-known and first application. This review represents an attempt to identify and substantiate future directions of research for the most significant implementations of Pinch Methodology. Reported applications in the literature range from Heat Integration, Total Site and Water Integration through to Emergy and even Financial Investment Planning; cutting across multiple engineering fields – Mechanical, Chemical, Process, Power, and Environmental Engineering – as well as entering the research domains of Management and Finance. Key findings of this review include: (1) the need for more awareness within the engineering and science research communities of the latest and continuing developments of the Pinch Methodology; (2) a need for complete tool sets covering targeting through to engineering design for many of the Pinch Methodology applications; and, (3) the full benefits of Pinch Methodology can only be achieved in developing design solutions with an appreciation for the most recent developments. Highlights • Pinch Analysis – more than 40 yr – systematic thermodynamic-based energy savings. • Extended – including water, power, hydrogen, supply chains, emissions, Total Sites. • Reviewed recent developments and suggested directions for future developments. • Future steps: exploiting the synergy, extend locally integrated regions. • As well as exergy, emergy, supply chains, targeting emissions and effluents. [ABSTRACT FROM AUTHOR]

• Quality-oriented recycling of plastic waste is proposed. • Data-driven Plastic Pinch Analysis to evaluate plastic waste recycling potential. • Machine learning approaches to define quality grades of plastic polymers. • The study showed maximum recyclability is 38% for PET, 100% for PE and 92% for PP. • Environmental impacts of recycling and treatment technologies are compared. The worldwide plastic waste accumulation has posed probably irreversible harm to the environment, and the main dilemma for this global issue is: How to define the waste quality grading system to maximise plastic recyclability? This work reports a machine learning approach to evaluating the recyclability of plastic waste by categorising the quality trends of the contained polymers with auxiliary materials. The result reveals the hierarchical resource quality grades predictors that restrict the mapping of the waste sources to the demands. The Pinch Analysis framework is then applied using the quality clusters to maximise plastic recyclability. The method identifies a Pinch Point – the ideal waste quality level that limits the plastic recycling rate in the system. The novel concept is applied to a problem with different polymer types and properties. The results show the maximum recycling rate for the case study to be 38 % for PET, 100 % for PE and 92 % for PP based on the optimal number of clusters identified. Trends of environmental impacts with different plastic recyclability and footprints of recycled plastic are also compared. [Display omitted] [ABSTRACT FROM AUTHOR]

Pressure drop is an important consideration in Total Site Heat Integration (TSHI). This is due to the typically large distances between the different plants and the flow across plant elevations and equipment, including heat exchangers. Failure to consider pressure drop during utility targeting and heat exchanger network (HEN) synthesis may, at best, lead to optimistic energy targets, and at worst, an inoperable system if the pumps or compressors cannot overcome the actual pressure drop. Most studies have addressed the pressure drop factor in terms of pumping cost, forbidden matches or allowable pressure drop constraints in the optimisation of HEN. This study looks at the implication of pressure drop in the context of a Total Site. The graphical Pinch-based TSHI methodology is extended to consider the pressure drop factor during the minimum energy requirement (MER) targeting stage. The improved methodology provides a more realistic estimation of the MER targets and valuable insights for the implementation of the TSHI design. In the case study, when pressure drop in the steam distribution networks is considered, the heating and cooling duties increase by 14.5% and 4.5%. [ABSTRACT FROM AUTHOR]

Pinch Analysis (PA) has been one of the most established methods since the 1970's for the design of a maximum heat recovery network. It has been one of the vital tools for maximising heat recovery in a process plant and for minimising the impact of rising energy cost as well as the environmental emissions. By combining the thermodynamic insights into the process heat recovery bottleneck with the HEN capital and operating cost tradeoffs, the PA has become an energy-saving tool widely used in the industry. However, further studies are needed to incorporate the safety aspect into HEN design using PA. Not fully considering the potential process hazards when selecting matches of hot and cold streams in a HEN can introduce process operation risk and consequently necessitate high investment in materials of constructions for heat exchangers. This work presents a new method for HEN design that incorporates the inherent safety index during the selection of heat exchanger matches in order to reduce the potential hazards of the optimal HEN design. Application of the extended PA on a case study shows that inclusion of the inherent safety feature has managed to localise the area of hazards, reduce the requirement for special materials of construction, and ultimately reduce the HEN capital cost by 10%. [ABSTRACT FROM AUTHOR]

This work aims to extend the previous Pinch Analysis framework to the industrial site material recycling network with site headers synthesis from single quality to multiple qualities. The analysis provides guided resources management strategy in any eco-industrial park to reduce the reliance on raw resources that are extracted from the environment. The Pinch Point(s) are first identified for the overall network using the Material Recovery Pinch Diagram for all the qualities. The guideline for the cross-plant material sources transfer is then built upon the concept of the Pinch Point(s) for all the qualities to minimise the cross-plant source transfer or a number of connections. An iterative header targeting framework is then proposed to determine the flowrates and the qualities of the headers. Two case studies, which have single and multiple qualities Total Site water recycling network, are used to demonstrate the proposed framework, comparing results obtained using direct integration and centralised headers. The single quality case results in 4.1% lower fresh resource intake compared to without cross-transfer, while the multiple qualities case could have 5.3% lower fresh resources for two and three plants scenarios. This framework provides a proper analysis of the problem, which allows users to gain insights on the effective cross-plant source transfer schemes with headers constraint by resource qualities. • Resources quality is the driving force for sustainable recycling of resources. • Guided strategies are proposed for minimal cross-plant source transfer with multiple qualities. • Real or 'pseudo' Pinch Points identification for multiple qualities are provided. • Iterative headers/mains parameters optimisation framework is provided. [ABSTRACT FROM AUTHOR]

Highlights: [•] Heat Integration (HI) has been an initial part of Process Integration (PI) for more 40 years now. [•] HI development has accelerated over the years. [•] The main two approaches are based on Pinch Analysis (PA) and Mathematical Programming (MP). [•] The paper overviews the developed and also pros and cons of both approaches. [•] HI has been contributing to sustainability—better utilisation and savings of energy and reducing emissions. [ABSTRACT FROM AUTHOR]

Hybrid energy systems have been widely used for residential and industrial purposes. In this system, the total energy requirement of each unit can be met with heat and electricity. Pinch Analysis becomes a widely used tool for Process Integration, and using Pinch Analysis for Heat Integration is well-established. However, for the combined heat and power system, the theory and the corresponding tool deserve some more development. This paper extended the Pinch Analysis concept and proposed a Heat and Power Pinch Analysis to target the amount of heat that should be recovered from the hybrid energy system. Heat and Power Composite Curve (HPCC) is developed to visualise the total energy and the separated heat and power (electricity) requirement of a hybrid energy system in a working time period. The amount of outsourced electricity that should be purchased, and stored electricity at the startup period, and the extra electricity generated by the system at the end of the working period can be demonstrated. A case is studied to illustrate the steps of using this tool, two scenarios are discussed, and the targets are shown. • A novel extension of Pinch Analysis for the hybrid heating and power system. • Targeting the required heat and power to meet the total energy demand. • A novel Heat and Power Composite Curve (HPCC) to visualise the targeting. • A case is studied to demonstrate the new tool. [ABSTRACT FROM AUTHOR]

• A graphical Water Scarcity Pinch Analysis (WSPA) is proposed. • Factors considered: the shortage of water quantity and insufficient water quality. • Water Scarcity Composite Curves identify the water quality and quantity targets. • A strategy for reduction and elimination of water scarcity. • Using water quality cascading and upgrading. Water quality problems contribute significantly to water scarcity. This study aims to redefine water scarcity caused by water quality degradation together with water quantity shortage and propose a Water Scarcity Pinch Analysis (WSPA) to quantify the regional water scarcity. WSPA is proposed based on the well-applied method of Water Pinch Analysis. The quality of water sources and demands is specified by setting water quality categories, based on which the staircase Grand Composite Curve (GCC) is constructed. After applying the water quality cascade, the GCC provides the water quantity-quality target, which is the net deficit volume (m3) of water with certain water quality (categories). The water quantity-quality target is defined as the regional water scarcity. Water quality upgrading is applied to maximise the water use efficiency for different purposes by mixing water sources with different qualities. Three case studies are set to illustrate the implementation of the proposed method and investigate the performance of the proposed WSPA. The results show that WSPA identifies both the water quantity scarcity and scarcity caused by insufficient water quality or the water quality mismatch between the sources and demands. Conclusions and novel contributions are i) WSPA enables accounting for water quality together with quantity in water scarcity assessment and provides both quantity and quality targets for minimising regional water scarcity; ii) Applying the WSPA to a macro level elevates the ratio-based water scarcity assessment from single determination to insight-based assessment that can guide the regional water resource management; iii) water quality cascade and water quality upgrade with water dilution can improve water use efficiency and reduce regional water scarcity. [ABSTRACT FROM AUTHOR]

Heat exchanger network (HEN) retrofit is a vital task in the process design to improve energy savings. Various types of heat exchangers such as shell and tube, double-pipe, compact plate, and spiral tube have their working temperature ranges and costs. Selecting suitable types of heat exchangers according to their temperature ranges and costs is a crucial aspect of industrial implementation. However, considering the type of heat exchangers in the HEN retrofit process is rarely seen in previous publications. This issue can be solved by the proposed Shifted Retrofit Thermodynamic Grid Diagram with the Shifted Temperature Range of Heat Exchangers (SRTGD-STR). The temperature ranges of six widely used heat exchanger types are coupled in the grid diagram. This diagram enables the visualisation of identifying the potential retrofit plan of HEN with heat-exchanger type selection. The retrofit design aims to minimise utility cost and capital cost. An illustrative example and a case study are presented to show the effectiveness of the method. [ABSTRACT FROM AUTHOR]

The energy and power sectors are critical sectors, especially as energy demands rise every year. Increasing energy demand will lead to an increase in fuel consumption and CO2 emissions. Improving the thermal efficiency of conventional power systems is one way to reduce fuel consumption and carbon emissions. The previous study has developed a new methodology called Trigeneration System Cascade Analysis (TriGenSCA) to optimise the sizing of power, heating, and cooling in a trigeneration system for a Total Site system. However, the method only considered a single period on heating and cooling demands. In industrial applications, there are also batches, apart from continuous plants. The multi-period is added in the analysis to meet the time constraints in batch plants. This paper proposes the development of an optimal trigeneration system based on the Pinch Analysis (PA) methodology by minimizing cooling, heating, and power requirements, taking into account energy variations in the total site energy system. The procedure involves seven steps, which include data extraction, identification of time slices, Problem Table Algorithm, Multiple Utility Problem Table Algorithm, Total Site Problem Table Algorithm, TriGenSCA, and Trigeneration Storage Cascade Table (TriGenSCT). An illustrative case study is constructed by considering the trigeneration Pressurized Water Reactor Nuclear Power Plant (PWR NPP) and four industrial plants in a Total Site system. Based on the case study, the base fuel of the trigeneration PWR NPP requires 14 t of Uranium-235 to an average demand load of 93 GWh/d. The results of trigeneration PWR NPP with and without the integration of the Total Site system is compared and proven that trigeneration PWR NPP with integration is a suitable technology that can save up to 0.2% of the equivalent annual cost and 1.4% of energy compared to trigeneration PWR NPP without integration. [ABSTRACT FROM AUTHOR]

To date, research on heat pumps (HP) has mainly focused on vapour compression heat pumps (VCHP), transcritical heat pumps (TCHP), absorption heat pumps, and their heat integration with processes. Few studies have considered the Joule cycle heat pump (JCHP), which raises several questions. What are the characteristics and specifics of these different heat pumps? How are they different when they integrate with the processes? For different processes, which heat pump is more appropriate? To address these questions, the performance and integration of different types of heat pumps with various processes have been studied through Pinch Methodology. The results show that different heat pumps have their own optimal application range. The new JCHP is suitable for processes in which the temperature changes of source and sink are both massive. The VCHP is more suitable for the source and sink temperatures, which are near-constant. The TCHP is more suitable for sources with small temperature changes and sinks with large temperature changes. This study develops an approach that provides guidance for the selection of heat pumps by applying Process Integration to various combinations of heat pump types and processes. It is shown that the correct choice of heat pump type for each application is of utmost importance, as the Coefficient of Performance can be improved by up to an order of magnitude. By recovering and upgrading process waste heat, heat pumps can save 15–78% of the hot utility depending on the specific process. [ABSTRACT FROM AUTHOR]

Research and development on integrated energy systems such as cogeneration and trigeneration to improve the efficiency of thermal energy as well as fuel utilisation have been a key focus of attention by researchers. Total Site Utility Integration is an established methodology for the synergy and integration of utility recovery among multiple processes. However, Total Site Cooling, Heating and Power (TSCHP) integration methods involving trigeneration systems for industrial plants have been much less emphasised. This paper proposes a novel methodology for developing an insight-based numerical Pinch Analysis technique to simultaneously target the minimum cooling, heating and power requirements for a total site energy system. It enables the design of an integrated centralised trigeneration system involving several industrial sites generating the same utilities. The new method is called the Trigeneration System Cascade Analysis (TriGenSCA). The procedure for TriGenSCA involves data extraction, constructions of a Problem Table Algorithm (PTA), Multiple Utility Problem Table Algorithm (MU PTA), Total Site Problem Table Algorithm (TS PTA) and estimation of energy sources by a trigeneration system followed by construction of TriGenSCA, Trigeneration Storage Cascade Table (TriGenSCT) and construction of a Total Site Utility Distribution (TSUD) Table. The TriGenSCA tool is vital for users to determine the optimal size of utilities for generating power, heating and cooling in a trigeneration power plant. Based on the case study, the base fuel source for power, heating and cooling is nuclear energy with a demand load of 72 GWh/d supplied by 10.8 t of Uranium-235. Comparison between conventional PWR producing power, heating and cooling seperately, and trigeneration PWR system with and without integration have been made. The results prove that PWR as a trigeneration system is the most cost-effective, enabling 28% and 17% energy savings as compared to conventional PWR producing power, heating and cooling separately. [ABSTRACT FROM AUTHOR]

The design of heat exchanger networks (HEN) in the process industry has largely focused on minimisation of operating and capital costs using techniques such as pinch analysis or mathematical modelling. Aspects of operability and flexibility, including issues of disturbances affecting downstream processes during the operation of highly integrated HEN, still need development. This work presents a methodology to manage temperature disturbances in a HEN design to achieve maximum heat recovery, considering the impact of supply temperature fluctuations on utility consumption, heat exchanger sizing, bypass placement and economic performance. Key observations have been made and new heuristics are proposed to guide heat exchanger sizing to consider disturbances and bypass placement for cases above and below the HEN pinch point. Application of the methodology on two case studies shows that the impact of supply temperature fluctuations on downstream heat exchangers can be reduced through instant propagation of the disturbances to heaters or coolers. Where possible, the disturbances have been capitalised upon for additional heat recovery using the pinch analysis plus-minus principle as a guide. Results of the case study show that the HEN with maximum HE area yields economic savings of up to 15% per year relative to the HEN with a nominal HE area. [ABSTRACT FROM AUTHOR]

Circular Economy is a well-known concept to mitigate global resource depletion issues. The sustainability of a system is closely related to its environmental performance, which is directly linked to energy consumption. This work provides a circularity assessment tool by determining the minimum system energy requirements, according to the Energy Quality Factor, as it indicates the useful energy that can be extracted from material and energy flows. The proposed tool is Energy Quality Pinch Analysis which identifies the minimum energy requirements for a circular system and shows the system's sustainability. The analysis considers cascades of the energy used and released by recycling and symbiosis processes, evaluating the minimal external energy flows: high-quality energy input and waste energy output. The method is applied to case studies, including Total Site Heat and Power Integration, chemical energy reuse in wastewater systems, and Municipal Solid Waste management. Practical energy conversion technologies in each study are proposed as well. The results of the case studies indicate that the degree of energy recovery rate can be as high as 60% for the case of the utility system and higher for the cases of wastewater and municipal waste treatment, providing potentially valuable guidance to system designers. [Display omitted] • Energy use of industrial and urban networks closely correlates with footprints. • Energy Quality Pinch Analysis is used as the targeting tool for symbiosis networks. • The proposed modelling framework can handle problems from different domains. • Case studies on utility systems, wastewater treatment and solid waste treatment. • Energy recovery ranges from 60% (utility system) to 100% (wastewater reuse). [ABSTRACT FROM AUTHOR]

Carbon emission neutralisation is the future target in many countries. Many sectors including the breeding industry, are contributing to achieve this target. Carbon emissions can be reduced by adjusting breeding and dietary structures. This study develops a Food-Carbon Emission Pinch Analysis tool for diet configuration optimisation to target possible greenhouse gas reduction. Several scenarios with different aims are considered to adjust the diet configuration in China and Zhejiang province. Results show that from the perspective of nutrition, replacing meat with equal protein mass of fish is more reasonable. 8.42 kg fish consumption should be increased, and 10.16 kg poultry and livestock meat consumption should be reduced annual per capita to reduce 10% food-carbon emission in Zhejiang province. For China as a whole, 9.88 Mt of poultry and livestock meat consumption should be reduced to achieve the 10% reduction target. If the reduced meat consumption is fully borne by the domestic breeding industry, the income of the domestic breeding industry would be reduced by 202,724 M CNY. It is recommended to reduce meat consumption by reducing meat imports and to increase the breeding and consumption of low-carbon fish rather than shellfish because of its extremely low carbon emission factor. [ABSTRACT FROM AUTHOR]

Water stress is becoming a major concern worldwide because of the lack of fresh resources to meet growing water demand in the face of climate change. Resources recycling is a viable option, but the main dilemma is to define a proper water quality grading system. This paper proposes a hybrid framework combining Machine Learning (ML) with Process Integration (PI) tools for assessing the regional water scarcity and recycling potential. The procedure involves defining the quality of water resources using supervised or unsupervised ML. Supervised ML (Classification) is employed when the data samples' origins or quality levels are known. The data can be sampled from an existing recycling system. The unsupervised ML (Clustering) method is used when quality levels are unknown. Data dimensionality reduction or expansion methods are used on the dataset to yield better classification or clustering outcomes. Once the hierarchical quality classes/clusters are revealed, the PI approach of Pinch Analysis is applied with the defined quality categories for planning water exchange systems (e.g., urban water networks or industrial parks). The method not only identifies the quality bottleneck of the system but also reveals the fresh resources deficit or excess of system supplies based on the defined quality clusters. This novel concept is demonstrated with case studies featuring different water sources and scenarios. Results show that the hybrid approach can categorise the water sources effectively, and depending on the number of defined clusters/categories, the water recycling potential can be different (e.g. with 5 clusters, the recyclability rate is 44%, while with 2 clusters, the recyclability rate can increase to 78% for the case study). The framework could serve as a guideline for regional authorities to manage the water resources according to their own water resources and properties database. [ABSTRACT FROM AUTHOR]

This paper proposes a novel method combining Pinch Methodology and waste hydrogen recovery, aiming to minimise fresh hydrogen consumption and waste hydrogen discharge. The method of multiple-level resource Pinch Analysis is extended to the level of Total Site Hydrogen Integration by considering fresh hydrogen sources with various quality. Waste hydrogen after Total Site Integration is further regenerated. The technical feasibility and economy of the various purification approaches are considered, demonstrated with a case study of a refinery hydrogen network in a petrochemical industrial park. The results showed that fresh hydrogen usage and waste hydrogen discharge could be reduced by 21.3% and 67.6%. The hydrogen recovery ratio is 95.2%. It has significant economic benefits and a short payback period for Total Site Hydrogen Integration with waste hydrogen purification. The proposed method facilitates the reuse of waste hydrogen before the purification process that incurs an additional environmental footprint. In line with the Circular Economy principles, hydrogen resource is retained in the system as long as possible before discharge. [Display omitted] • Integration and recovery of hydrogen in networks at Process and Total Site context. • Consideration of fresh hydrogen sources at different quality levels. • Hydrogen Pinch Analysis is extended to Total Site scope and multiple-level fresh sources. • Sustainable waste hydrogen recovery design by techno-economic performance. • The case study reduced fresh hydrogen and waste hydrogen by 21.3% and 67.6%. [ABSTRACT FROM AUTHOR]

Abstract: The paper deals with an extension of Total Site Integration to Locally Integrated Energy Sectors producing more realistic utility and heat recovery targets. Process Heat Integration (based on Pinch Analysis) aims to minimise the amount of energy mostly used in industrial processes. It is still an open question how to solve the Total Site targeting problem when different values for the minimum allowed temperature differences (ΔT min) are specified for each process on the site. A single uniform ΔT min for all processes integrated in a Total Site, as practiced to date, cannot be generally optimal. Such an assumption may be too simplifying and lead to inadequate results due to imprecise estimation of the overall Total Site heat recovery targets. The modified Total Site targeting procedure, proposed in this paper, allows obtaining more realistic heat recovery targets for Total Sites. It is illustrated with a case study for Locally Integrated Energy Sectors, also providing a comparison with the traditional targeting procedure and the advantages offered by the modified one. [Copyright &y& Elsevier]

• Total site material integration with headers to minimise fresh resource intake. • Minimise source transfer with various cross-plant source transfer schemes. • Headers/mains parameters targeting approach with graphical interface is proposed. • The algorithm solves the mixed integer non-linear site headers design problem. • The fresh resource intake is 4.1% lower compared to without cross-plant transfer. Proper resources recycle or reuse planning helps the industrial sites to reduce reliance on raw resources. There are a lot of previous researches that had applied the Pinch Analysis on the resources recycling problem. However, there is not much work completed on targeting the materials headers or mains from the sources of the plants. This work extends the Material Recovery Pinch Diagram to provide an insightful yet straightforward approach to targeting the material headers/mains with minimum fresh resource consumption (e.g. water, hydrogen or CO 2) with single quality. The flowrates and the concentration of the exchanged streams in the material headers, as well as the minimum number of headers, can be targeted using a Pinch-based strategy, which can be applied at either process or Total Site scale. This study also proposes a novel algorithm to minimise the cross-plant material source transfer for the Total Site material network with header/mains design while ensuring the overall minimum fresh resource target is satisfied. A Source Transfer Diagram is proposed to identify optimal reuse opportunities of the purged sources from individual plants. A case study is used to demonstrate the proposed framework, comparing results obtained using direct integration and centralised headers. The benefits of this framework are two-fold. It provides the minimum resource consumption rates for the overall network, and it also enables the network and mains/header design through graphical visualisation, which is a non-linear problem. The graphical interface allows users to explore different source mixing options from individual plants while ensuring the number of headers, resource consumptions, and cross-plant source transfer are minimal. [ABSTRACT FROM AUTHOR]

The paper presents an extension of Pinch Analysis and namely, Total Site Process Integration. It benefits from up to date developments and introduction of Total EcoSite Integration for urban and industrial symbiosis. An important development is Pinch Analysis for Solid Waste Integration which is a crucial step for the symbiosis in a circular economy. As the potential EcoSites are usually extensive and cover various units, a methodology based on clusters has been used. The solution has been supported by graphical tools using the analogy with already implemented extensions of Pinch Analysis. The results of a demonstration case study revealed the potential of the novel approach. The identified integrated design increased the energy recovered from the solid waste by 11.39 MWh/d and diverted 2 t/d of the waste from the landfill, benefiting both the urban and industrial site. The proposed approach is also capable of minimising the requirement of energy-intensive thermal drying for waste whenever the process allowed, subsequently offer a solution with lower environmental footprint and cost. For future work, a even more comprehensive case study can be conducted by considering the other forms of the waste, recovery process and drying approaches. Image 1 • Total EcoSite Integration is proposed for symbiosis in Circular Economy. • A Pinch Analysis based method for Solid Waste Integration is newly introduced. • The integrated design increases the heat recovered from the solid waste by 20%. • About 2 t/d of solid waste is diverted through Industrial and Urban Symbiosis. • Required hot utility in the industrial process (960 MW) and drying is minimised. [ABSTRACT FROM AUTHOR]

Assessments of hotspot analysis and process optimisation followed by improved design are essential to achieve cleaner production. Cleaner production also involves complex interactions with economic and social performance. It plays a substantial role in sustainable development. This contribution presents an overview of cleaner production achievements and selection of relevant recent work dealing with optimisation tools and process design as published in the Special Issue on Process Integration and Intensification for Sustainable Evolution via Resource and Emission Reduction. The cleaner production tools including Pinch Analysis, Process Graph, Artificial Intelligence and computer-aided modelling, are reviewed. The roles of waste streams as secondary resources process design in cleaner production and circular economy is also discussed. The highlights of the recent development contribute to the field of study by drawing out the attention for potential future research. [ABSTRACT FROM AUTHOR]

Hybrid power systems are becoming more popular nowadays as they provide a good transition towards renewable energy systems integration while still maintaining power sources from fossil fuels. Uncertainties based on seasonal changes, weather patterns and demand fluctuations have been considered. Disasters such as earthquake, tornado and hurricane are becoming more frequent and unpredictable as climate change is affecting major parts of the world. Safety and resilience are two important aspects that need to be taken into consideration in designing power systems due to the increase in extreme weather and natural disasters. Safety precautions are taken into consideration to withstand major damage and ensure the power system can continue to run smoothly with no or little interruption to the power supply. Previous studies focused on optimizing the cost and efficiency of the system based on season change, weather and demand fluctuations. The purpose of this research is to develop a novel methodology to design a hybrid power system considering resilience and safety aspects. This research primarily focuses on the use of Decision Matrix Risk Assessment Technique (DMRA) and Power Cascade Table (PCT) to evaluate the impact of disasters towards the power systems with and without safety consideration. The results of the case study have shown that the implementation of safety can reduce the total cost by up to USD209.3 M when catastrophic events occur. [ABSTRACT FROM AUTHOR]

Water is extensively used in industry for processes such as washing, stripping, extraction, heating and cooling. Growing world population, rising price of freshwater and stricter environmental regulations have motivated efforts for efficient water management and utilisation in industry. Even though research on Water Integration at Total Site have been well-documented, there are still a few critical issues that need to be adequately addressed. Complex water exchange networks that have typically resulted from superstructure optimisation at Total Site can be costly and less favourable for practical implementation. In this paper, the concept of one-way centralised water reuse header (CWRH) is applied for Water Integration at Total Site for a simpler and easy-to-manage inter-plant water reuse and exchange. Process plants are assumed located along the centralised water reuse header, and water is exchanged along the one-way pipeline. The CWRH system can be operated by a third-party, allowing the operator to protect users’ proprietary information and confidential data. Total Site Centralised Water Integration (TS-CWI) is developed to target the minimum freshwater requirement and wastewater generation across Total Site. The methodology is illustrated using a case study comprising of five plants located along two centralised water reuse headers. Results demonstrate that the Total Site freshwater requirement and wastewater generation are reduced by 72.3%, (from 2,540 t/h to 702.4 t/h) and that the TS-CWI resulted in a much simpler Total Site Water Network that led to significant reductions in piping and pumping costs. [ABSTRACT FROM AUTHOR]

The difference in electricity pricing based on the time of power use has led to load shifting from peak to off-peak hours in hybrid power systems (HPS). Apart from optimising electricity cost, shifting of the load may also change the capacity of storage in the system. Power Pinch Analysis has been recently applied to guide load shifting aiming to minimise the cost of electricity, considering the peak and off-peak electricity pricing. The HPS was assumed to be ideal with 100% efficiency, which is not achievable in actual operational condition. This work extends the study by scrutinising the effects of peak-off-peak load shifting on the capacity of storage in HPS. The effects of energy losses due to the inefficiency during power conversion, transfer and storage in the HPS are considered in developing shifting heuristics to ensure optimal storage size is achieved. Implementation of the proposed load shifting strategy on a case study demonstrates that a reduction of up to 30% in the storage size can be achieved, which led to a minimum storage cost. The distribution of peak hours' demand to off-peak hours also successfully provide significant savings in the electricity bill. [ABSTRACT FROM AUTHOR]

Total Site (TS) analysis for incorporating short-term or daily energy variation has been introduced in the previous studies as an extension of the Time Slice Model for the Heat Integration of batch processes. However, the energy supply and demand fluctuation could also be affected by changing customer demands due to seasonal climate variations, economic downturn, maintenance, plant turn-around, plant operability issues and raw material availability. This paper extended the cascade energy targeting methodology for TSHI incorporating long- and short-term heat energy supply and demand variation problem. The methodology aims to estimate the energy requirements of the TS system considering seasonal energy storage system as a feasibility study for energy efficiency project. A newly extended algebraic tool, known as Seasonal Total Site Heat Storage Cascade (Seasonal TS-HSC), is introduced in the methodology for modelling the energy flow between process units and storage facilities. The general tool could be used for different storage systems. This proposed tool includes the estimation of energy losses through self-discharge, charge and discharge process based on the energy storage system performance. The methodology is illustrated by a case study, which integrates batch processes, community buildings and space heating system. Implementation of the developed methodology on the case study resulted in 93.4% (low-pressure steam - LPS) and 38.2% (hot water - HW) heating requirement reduction via seasonal energy storage system application at two utility levels. The result shows the energy requirement reduction, which contributes to profitability margin improvement, greenhouse gas emission reduction potential and regional sustainability enhancement, through seasonal energy storage system in the industrial energy system. [ABSTRACT FROM AUTHOR]

Carbon dioxide emissions coming from industrial, transport, service and business activities as well as methane and nitrogen oxides from agriculture are major greenhouse gases with high global warming potentials. Modelling tools for the optimal management and reduction of greenhouse gas emissions, in particular, carbon dioxide, have received growing attention. Concurrently, complementary graphical and visualisation tools for carbon dioxide targeting, design and planning based on Pinch Analysis have evolved in line with the developments of other Process Integration tools. The application of Pinch Analysis includes the conservation of resources including heat, mass, water, gas, materials, property, solid, and more recently, power. This paper provides a comprehensive review of the development of Process Integration insight-based graphical, algebraic and numerical tools for carbon dioxide emission reduction. The key focus of the review is on methodologies that are capable of making explicit assessment on, and quantify the impact of the use of the PI tool on CO 2 reduction, covering works from 2007 (when it was initially introduced) until year 2016. The review has been categorised into supply side energy and emission planning as well as demand side and end-of-pipe energy and emission management. The aim of the review is to provide researchers, industrial planners, policy-makers and energy managers awareness of the appropriate insight-based graphical, algebraic and visualisation Process Integration tools that are available for use for carbon dioxide emissions planning and reduction. Applications of such tools is expected to enhance their conceptual understanding of the problems and ultimately help them make better decisions during the planning and management of greenhouse gas emissions. [ABSTRACT FROM AUTHOR]

The development of Process Integration has paved the way for many generic application avenues for the efficient management of energy and resources. However, there is a need to develop a framework to guide industrial site planners to most efficiently exploit and benefit from the suite of Pinch Analysis tools in an integrated manner towards systematically planning a low CO 2 emissions, while strongly promoting cleaner production alternatives. This work presents an attempt to develop a systematic framework for low CO 2 industrial site planning, using an integrated set of Pinch Analysis related tools with algebraic algorithms established to complement the graphical representation. The proposed framework consists of four main stages. The first stage involves the baseline study of resources. The second stage involves Total Site Heat Integration to maximise heat recovery among multiple units, while simultaneously targeting for cogeneration potential. The third stage involves application of Power Pinch Analysis to optimise power allocation and integration of hybrid renewable energy system. CO 2 Emissions Pinch Analysis is applied in the final stage to achieve the minimum CO 2 targets via implementation of a CO 2 emissions management hierarchy (CMH) to systematically explore options to maximise CO 2 reductions. Application of this systematic framework to an illustrative industrial site case study resulted in an overall reduction of 56.7% in heat, 74.3% in power, and 99.8% in CO 2 emissions. This proposed tool for low CO 2 industrial site planning is available for designers, planners and industrial site owners to optimise integrated energy and CO 2 emissions for Total Sites, starting from the individual process units, and ready to be extended to Locally Integrated Energy Systems. [ABSTRACT FROM AUTHOR]

There has been growing interest in developing Locally Integrated Energy Sectors (LIES) as a Process (Heat) Integration approach for synergising the industrial thermal energy systems that include renewable energy resources with urban (i.e. civic, residential, business and service complexes). The aim is to enhance the regional energy efficiency and minimise greenhouse gas (including carbon) emissions. However, a comprehensive planning and design framework is crucial at the onset of its development, which is accounting for supply and demand sides, but there have been limited works directed to this scope to date. For the development of such framework, this paper reviews the energy consumption targeting methodologies via Total Site Heat Integration for estimating and designing the capacity of the utility have been reviewed in this work, inclusive of both insight-based Pinch Analysis and mathematical modelling approaches. As a final outcome of the review, suggestions are provided for investigating key factors for integration of industrial, residential, commercial, institutional and service energy systems, maximising the integration and reuse of waste and low potential heat, including renewables to boost sustainability aspects. The review of methodologies for energy system integration is followed by identification of research directions that deserve future attention, refinement and development. [ABSTRACT FROM AUTHOR]

A nuclear reactor can generate a large amount of high-temperature waste heat, which can be recovered to produce simultaneous electricity, heating and cooling, known as a trigeneration system. Trigeneration System Cascade Analysis is a methodology based on Pinch Analysis to optimise a centralised trigeneration system in various energy ratings in demands. However, the previous study does not consider a complete life cycle costing in the Trigeneration System Cascade Analysis. The methodology consists of three main parts, which are data extraction, development of Trigeneration System Cascade Analysis, and calculations of the life cycle costing. In this analysis, a centralised Pressurised Water Reactor, which is the most commonly used nuclear reactor in the world, is applied in a trigeneration mode in three different industrial plants. Based on the results of the case study, an optimal Pressurised Water Reactor trigeneration system is obtained where the total thermal energy required is 1,102.25 MW or translated into 26.5 GWh/d. The Equivalent Annual Cost for the case study, on the other hand, showed the centralised Pressurised Water Reactor trigeneration system requires 1.89 × 1011 USD/y for maintaining, operating, constructing, and disposing of the overall Pressurised Water Reactor trigeneration system. The maintenance cost is the highest percentage which constitutes 51.3% of the overall cost. Comparisons between normal conditions, and planned and unplanned shutdowns are also conducted, and the results show that Equivalent Annual Costs of planned and unplanned shutdowns required an additional 1.4 MUSD and 0.5 MUSD to support the deficit energy during shutdowns. The implementation of the full life cycle costing during the normal conditions planned and unplanned shutdowns of the Pressurized Water Reactor trigeneration system gives a proper projection of the cash flows that can create an economic model that reflects all the project realisation conditions. [ABSTRACT FROM AUTHOR]

Valorisation of organic waste can lead to cleaner production in the energy sector. One factor affecting the decision for organic waste valorisation to value-added products through biological processes is the carbon-to-nitrogen (C/N) ratio. All biological processes have preferential C/N ratios for optimum performance, while organic waste comes with a wide range of C/N ratios. The mismatch of the C/N ratio between the supply stream (organic waste) and the demand stream (biological process) can lead to suboptimal process performance and affect resource allocation. In this study, a new graphical C/N ratio Pinch Analysis approach was proposed by plotting cumulative carbon mass flowrate versus the cumulative nitrogen mass flowrate as x- and y-axes for the supply and demand sides. A series of graphical Supply Composite Curve (SCC) shifting, namely SCC right-shifting, SCC end-shifting, SCC detaching, and SCC down-shifting, were developed explicitly tackling different supply stream conditions in the hypothetical case studies while satisfying the demand streams with the aid of external supply. The external supply was determined by filling the gaps formed after the SCC was shifted to the right of the Demand Composite Curve (DCC). Specific heuristics were established to assess the range of C/N ratio for the external supply that is eligible and preferred to satisfy the demand streams. Stepwise procedures for mass flowrate allocation to mix the supply and match the demand were introduced. In this study, the demands for Case Study 1 were satisfied by 59.15% OWLA with 40.83% ES 3. For Case Study 2, the demands were satisfied by 76.19% OWLA with 23.81% ES 1. For Case Study 3, the demands were satisfied by 91.54% OWLA with 8.46% ES 1. The integration of the C/N ratio element in the Pinch-based Analysis of SCC shifting and exploring new optimisation scope can act as an advising tool for any individual, party, or organisation to optimally valorise the organic waste found within a local region. • Valorise organic waste via Pinch Analysis focusing on the carbon-to-nitrogen ratio. • Introduction of heuristics to determine the eligible and preferred external supply. • Stepwise procedures for mass flowrate allocation from supply to demand. • Majority of the demand mass flowrates satisfied by organic waste locally available. • Developed methodology applicable to any bioprocesses by valorising organic wastes. [ABSTRACT FROM AUTHOR]

Heat Pinch Analysis retrofit projects are typically performed by evaluating and maximising the heat recovery potentials within the individual process units. Once the potential improvements from the individual units have been assessed, the Total Site (TS) Heat Integration analysis is performed. Such approach may steer designers away from the promising retrofit opportunities and to lead towards suboptimal heat exchanger networks (HEN). This paper presents an effective retrofit framework for a TS system to determine the most cost-effective retrofit options and maximise the potential savings. Instead of performing the typical unit-wise process retrofit, the strategy is to determine the baseline total site consumption and benchmark targets, and to identify retrofit options from the TS context. This TS retrofit framework has been tested on a case study involving a petrochemical plant comprising of multiple process sections. The results of the analysis show that significant energy savings can be realised when both direct and indirect heat recovery retrofit options are evaluated. Further energy savings can be achieved via the Plus–Minus Principle that helps pinpoint the correct locations of heat surpluses and deficits and lead to the appropriate TS retrofit solution. As a conclusion, energy retrofit projects should be approached from the TS context, followed by the unit-wise retrofit (i.e., retrofit of the individual process sections). [ABSTRACT FROM AUTHOR]

Abstract: Analysis of steam and water losses in the Total Site (TS) utility system is critical in process industry. Makeup water plays an important role in maintaining the water balance in the steam and condensate systems. Total Site Heat Integration (TSHI) offers a solution to increase energy savings as well as energy efficiency and consequently, to promote sustainability. However, so far most studies on TSHI have not considered the water sensible heat in TS targeting; e.g. for Boiler Feed Water (BFW) preheating and steam superheating during steam generation. In this work, an extended methodology is developed to target the minimum utility requirements in a steam system that considers the water sensible heat. The Extended Total Site Problem Table Algorithm (TS-PTA) is proposed as a systematic numerical tool to consider the sensible heat while targeting the Total Site utility requirements. The Extended Site Composite Curves (ESCC) are developed as a visualisation tool for the Extended TS-PTA. Illustrative and industrial case studies are used to verify the methodology. The results demonstrate the significance of considering the sensible heat of water on the TS utility targets. [Copyright &y& Elsevier]

Abstract: Total Site Heat Integration (TSHI) is a technique of exchanging heat among multiple processes via a centralised utility system. An analysis of the integrated multiple processes, also known as the Total Site (TS) system sensitivity, is needed to characterise the effects of a plant maintenance shutdown, to determine the operational changes needed for the utility production and to plan mitigation actions. This paper presents an improved Total Site Sensitivity Table (TSST) to be used as a systematic tool for this purpose. The TSST can be used to consider various ‘what if’ scenarios. This tool can be used to determine the optimum size of a utility generation system, to design the backup generators and piping needed in the system and to assess the external utilities that might need to be bought and stored. The methodology is demonstrated by using an Illustrated Case Study consisting of three processes. During the TS normal operation, the Total Site Problem Table Algorithm (TS-PTA) shows that the system requires 1065kW of High Pressure Steam and 645.5kW of Medium Pressure Steam as the heating utility, while for the cooling utility, 553.5kW of Low Pressure Steam and 3085kW of cooling water are required. The results of the modified TSST proposed that a boiler and a cooling tower with the system design requiring a maximum capacity of 2.172MW of steam and 4.1865MW of cooling water are needed to ensure an operational flexibility between the three integrated processes. [Copyright &y& Elsevier]

• Extension of single contaminant Material Pinch Analysis to multi-contaminants. • Pre-targeting procedure to determine the source prioritisation for a specific sink. • Reaching all contaminants limits of sinks is the optimal source allocation strategy. • Sequential sink targeting directly determines the source allocation network design. • Graphical results obtained are consistent with results from mathematical approach. An extended targeting and synthesis procedure using the Pinch approach has been developed for material resource conservation networks with multiple contaminants (e.g. water recycling network with multiple constraints). The Sink and Source Composite Curves (CC) are constructed for each contaminant (load vs flowrate). In this work, a 'polygon' rule is introduced for the CCs representation that illustrates the feasibility of the source mixing. The Source CCs for all the contaminants have to be shifted at least until a 'polygon' is formed around the vertices of the Sink CCs, with lines represent the edges of the Source and Sink CCs. The framework first identifies a freshwater target for each sink with Pinch Analysis based on the pre-determined source arrangement. A condition for further reduction of the freshwater is then checked with the proposed algorithm. Pinch Analysis of each sink sequentially enables the freshwater target and the optimal network design with allocated sources flowrates to be determined. [ABSTRACT FROM AUTHOR]

Abstract: Pinch Analysis is a well-established methodology of Process Integration for designing optimal networks for recovery and conservation of resources such as heat, mass, water, carbon, gas, properties and solid materials for more than four decades. However its application to power systems analysis still needs development. This paper extends the Pinch Analysis concept used in Process Integration to determine the minimum electricity targets for systems comprising hybrid renewable energy sources. PoPA (Power Pinch Analysis) tools described in this paper include graphical techniques to determine the minimum target for outsourced electricity and the amount of excess electricity for storage during start up and normal operations. The PoPA tools can be used by energy managers, electrical and power engineers and decision makers involved in the design of hybrid power systems. [Copyright &y& Elsevier]

Severe environmental issues such as excessive energy and water resources consumption and massive carbon emissions are becoming progressively prominent. Energy, water and carbon emissions are also intrinsically linked and have become the critical indicators for sustainable development. Nexus analysis between the three resources has been increasingly emphasised, mainly using mathematical programming approaches. Applications of insight-based approach for nexus study, however, have been directed very few attentions. This paper presents a new framework for the optimal design of integrated energy-water systems based on Pinch Analysis considering the energy-water-carbon emissions nexus. The framework consists of a series of Pinch Analysis methods, specifically Power Cascade Table (PCT), Water Cascade Table (WCT) and Energy Planning Pinch Diagram (EPPD), to obtain the minimum targets for each resource. The established targets provide valuable insights to assess the whole integrated system following any design modifications on certain resource networks. The framework was tested on a small-scale industrial plant case study, where adjustments on the system design were performed to achieve 20% CO 2 gas discharge reduction target. The final integrated design gave minimal impacts of up to 12% changes on the energy system, while the water system deviates by less than 1% from the initial design. The outputs from the framework can assist designers in the planning of their integrated energy-water systems while meeting the environmental requirements. [ABSTRACT FROM AUTHOR]

A novel energy targeting framework is proposed to analyse an urban-industrial symbiosis (UIS) system by incorporating Heat Integration, Power Integration, heat storage, power storage, renewable energy sources, and waste heat cogeneration. A trigeneration power plant is incorporated into the framework to connect the multi-energy microgrid. The trigeneration system provides high operational flexibility of the UIS through the manipulation of system outputs. This framework can handle multiple heating and cooling grids, which have different temperatures. An illustrative case study is also developed to demonstrate the proposed Pinch-based multi-energy targeting framework. The energy requirement of the heating-cooling-power microgrid in the UIS is successfully targeted. With the flexible trigeneration load estimated based on the thermal energy requirement of the UIS, the case study shows 34% of energy-saving opportunities and a payback period within a year. The case study suggests that the constant load operation can reduce the design capacity of the trigeneration system; however, the energy loss in the energy storage increases the utility cost and causes the system less attractive. • The feasibility evaluation of CCHP microgrid in urban-industrial symbiosis. • Integrating industry and urban with renewable energy, heat, and battery systems. • Minimum requirements in microgrids for heating, cooling and electricity are targeted. • Trigeneration satisfies the requirement of a multi-energy microgrid in the UIS. • The constant and flexible trigeneration load operations are considered. [ABSTRACT FROM AUTHOR]

• Multi-contaminant resource targeting via Pinch Analysis. • Assignment of sinks to proper contaminant cascade based on limiting contaminant. • Pre-targeting steps are proposed to pre-process sources and sinks. • Sources are prioritised so that all impurity constraints are active for contradicting sources. • Sequential Pinch Analysis for various contaminants are proposed. This work presents a systematic resource targeting procedure in the domain of multiple contaminants water recycling/reuse network. A resource-allocation model was developed and modified to determine the model characteristics, to obtain the optimal solution. By inferring from the formulations, it is recognised that each water sink is constrained by a certain contaminant. This plays a vital role in determining the assignment of sinks to the proper contaminants cascade, classifying them to below or above the Pinch Region, and the source allocation strategy. Multiple Targeting Pinch Diagrams with Source and Sink Composite Curves then should be plotted for each contaminant. Each contaminant is assigned a specific separate Pinch Plot and analysed sequentially until the demands of all sinks are fulfilled. The credibility of the novel approach is demonstrated by several industrial case studies encompassing problems with a fresh and impure resource. The method provides insights into the problem while providing the minimum resource target. [ABSTRACT FROM AUTHOR]

Heat exchanger network (HEN), which is designed to achieve the maximum energy recovery (MER) involves the integration and interactions of multiple process streams. In a plant, the system operation may experience various disturbances such as changes in supply temperature and flowrates. Small disturbances on one stream can affect other connecting streams. To manage these disturbances, the process to process and utility heat exchangers with bypass streams installation are typically overdesigned, leading to higher capital investment. This study presents the cost optimisation of flexible MER HEN design which considers the fluctuation probability using Break-Even Analysis (BEA). Stream data is extracted for the Pinch study and assessment for flexibility and MER was performed. The MER heat exchanger maximum size (MER-HEM) able to handle the most critical supply temperature fluctuations while minimising the utility consumption is calculated. However, the overdesign factor can affect the total annualised cost (TAC) at a certain probability of fluctuation occurrence. Besides that, the fluctuations experienced by the stream can result in the utility increasing or decreasing. Therefore, the MER heat exchanger original size (MER-HEO) is favoured when the fluctuation resulted in the utility cost increasing. The BEA is performed to determine the probability that results in high savings of the TAC and developed an optimal HEN design of MER-HEM or MER-HEO. The break-even point (BEP) from BEA indicate the exact fluctuation probability at which the TAC of MER-HEM and MER-HEO is the same. A case study with fluctuation probability over one-year operation is used to demonstrate the methodology. Application of the proposed methodology on the case study shows that the optimum size of heat exchanger can be determined and the additional savings of TAC can be achieved. • A new tool for MER HEN design with impact of the probability fluctuations. • The tool enables the selection of optimal heat exchanger size and total annual cost. • Trade-offs between MER, heat exchanger size, utility requirement and total annual cost. [ABSTRACT FROM AUTHOR]

The hybrid power system (HPS) that integrates diesel/biodiesel plant with renewable energy (RE) technologies has become increasingly popular to alleviate greenhouse gases emissions issue of the sole diesel/biodiesel power system. Integrated diesel-RE power system offers cleaner power supply while minimising cost of diesel fuel and diesel system maintenance. The use of Power Pinch Analysis (PoPA) method for the integration of diesel plants and RE systems into HPS with the objective to minimise fuel requirement and operational time of diesel generator has been presented. This work aims to achieve the same objective via probability theory utilisation, to simplify the PoPA procedure involving the matching of various routes for power flows. The extended technique called the Probability-Power Pinch Analysis (P-PoPA) can give accurate results as those established from the PoPA method within a shorter analysis time because it replaces the tedious manual matching step with correction factors. All probable routes of power from RE and diesel generators to demands are considered in computing the correction factors, in order to target the minimum diesel power in the integrated system. The result of a Case Study demonstrates that 19% saving in diesel fuel consumption can be realised if the present diesel station is supported with renewable solar power in an HPS. The result of the P-PoPA method is accurate with a very minor deviation to that from the conventional PoPA technique. [ABSTRACT FROM AUTHOR]