A complex autonomous inventory coupled system is considered. It can take, for example, the form of a network of chemical or biochemical reactors, where the inventory interactions perform the recycling of by-products b...A complex autonomous inventory coupled system is considered. It can take, for example, the form of a network of chemical or biochemical reactors, where the inventory interactions perform the recycling of by-products between the subsystems. Because of the flexible subsystems interactions, each of them can be operated with their own periods utilizing advantageously their dynamic properties. A multifrequency second-order test generalizing the p-test for single systems is described. It can be used to decide which kind of the operation (the static one, the periodic one or the multiperiodic one) will intensify the productivity of a complex system. An illustrative example of the multiperiodic optimization of a complex chemical production system is presented.展开更多
Coal dependence and inefficient decentralized heating have significantly increased China’s energy consumption for winter heating,increasing air pollution and exacerbating the greenhouse effect.In 2017,China implement...Coal dependence and inefficient decentralized heating have significantly increased China’s energy consumption for winter heating,increasing air pollution and exacerbating the greenhouse effect.In 2017,China implemented the Pilot Policy on Clean Winter Heating in Northern China,aiming to achieve high central heating coverage and cleaner energy consumption.Studying the effects of this policy can help promote its implementation and serve as a reference for effective adjustment of the contents in the future.However,few studies have investigated this policy and its carbon reduction effects,and most focus on the provincial or city levels.Therefore,this paper considers the policy’s influence on air pollution and carbon emissions at the county level to provide a precise and comprehensive assessment of the policy effects.We use panel data from 1290 counties in 15 provinces in Northern China from 2014 to 2021,applying a multiperiod difference-in-differences model to quantify the impact of the policy on carbon emissions and air quality in the pilot area.We then conduct a series of tests to demonstrate the robustness of the results and analyze the mechanisms of the policy effects from two perspectives,namely,central heating and natural gas use,through a mediating effect model.Finally,we examine the heterogeneity of policy effects between counties based on geographic location and per capita income levels of rural residents through a moderating effect model.The results reveal that the policy significantly reduces air pollution and carbon emissions in the pilot area by increasing the central heating area and natural gas use.Compared with the central and western regions in the north and areas with low-income rural residents,the policy effects in the eastern regions in the north and areas with high-income rural residents are more pronounced.展开更多
This study highlights the changing priorities of China’s paired assistance throughout the past decades,as well as its theoretical implications and economic growth effects for recipient regions.Using panel data from 3...This study highlights the changing priorities of China’s paired assistance throughout the past decades,as well as its theoretical implications and economic growth effects for recipient regions.Using panel data from 32 prefecture-level cities from 1990 to 2020,this study uses the multiperiod difference-in-differences approach to examine how paired assistance has contributed to economic growth in Xizang Autonomous Region and Xinjiang Uygur Autonomous Region.The findings indicate that,first,the implementation of the paired assistance policy has boosted economic growth in Xizang and Xinjiang.Second,paired assistance has stimulated economic growth in recipient communities by improving infrastructure.Third,paired assistance has contributed to economic growth in recipient communities by providing improved public services such as education and healthcare.Improvements to public services have a relatively smaller indirect effect in short term than infrastructure development on economic growth.Yet both education and healthcare are crucial to people’s quality of life in recipient communities.This paper has refined and broadened research on the effects of paired assistance,providing preference for future policymaking.展开更多
The current portfolio model for property-liability insurance company is only single period that can not meet the practical demands of portfolio management, and the purpose of this paper is to develop a multiperiod mod...The current portfolio model for property-liability insurance company is only single period that can not meet the practical demands of portfolio management, and the purpose of this paper is to develop a multiperiod model for its portfolio problem. The model is a multistage stochastic programming which considers transaction costs, cash flow between time periods, and the matching of asset and liability; it does not depend on the assumption for normality of return distribution. Additionally, an investment constraint is added. The numerical example manifests that the multiperiod model can more effectively assist the property-liability insurer to determine the optimal composition of insurance and investment portfolio and outperforms the single period one.展开更多
Dealing with uncertainty is one of practical issues in design and operation of heat exchanger networks(HENs),arising the problem of flexible HEN synthesis.This paper addresses the state-of-the-art methods for flexible...Dealing with uncertainty is one of practical issues in design and operation of heat exchanger networks(HENs),arising the problem of flexible HEN synthesis.This paper addresses the state-of-the-art methods for flexible HEN synthesis based on sensitivity analysis,resilience analysis,flexibility analysis and multiperiod synthesis techniques as well.Each of these methods is summarized by presenting their general procedures and recent developments on modeling,solving strategies and applications.Some current topics related to flexible process synthesis have been briefly presented to provide several future research possibilities.展开更多
The cumulative expression of multistage deformation is complex multiperiod fractures,which are commonly seen in tectonic zones.The Middle Triassic Leikoupo Formation in the western Sichuan Basin Depression,China,is a ...The cumulative expression of multistage deformation is complex multiperiod fractures,which are commonly seen in tectonic zones.The Middle Triassic Leikoupo Formation in the western Sichuan Basin Depression,China,is a typical marine carbonate reservoir with natural fractures caused mainly by tectonic movements.According to outcrops,drill cores,image logging,and fluid inclusions,the fracture characteristics,types of natural fractures,and interactions of fractures are determined.In total,419 natural fractures in 493.2 m of cores from 7 wells are investigated,which are mainly shear and tensile fractures with a small number of weathering generated fractures.Meanwhile,the results of the stable isotope analysis of δ13C and δ18O,as well as the flow fluid inclusion data,reveal four tectonic periods of fractures with different occurrences.Based on the history of regional tectonic evolution,indicating one period of weathering fractures ascribable to stratal uplift and three periods of structural fractures related to the sequential tectonic movements of the Longmenshan fault belt.By analyzing the interaction relationships of fractures,three types of fracture interaction relationships are observed:cutting,restraining,and overlapping.The four stages fractures are chronologically assigned to(1)the early Indosinian N-S trending compression,(2)the late Indosinian NW-SE compression,(3)the middle Yanshanian NE-SE compression,and(4)the early Himalayan E-W compression.The influence of natural fractures on gas migration and well production in marine carbonates is discussed,and indicates that tectonic fractures could provide seepage channels for gas migration and accumulation from near or distant hydrocarbon source rocks into the Middle Triassic Leikoupo Formation.This study utilizes a pragmatic approach for understanding the fracture genesis mechanism in oil and gas field with multiperiod fractures.展开更多
Cooling water systems(CWSs)are extensively utilized in various industries to eliminate the excess heat and converse energy.Studies on CWSs mainly concentrated on finding the optimal cooler network structure.In additio...Cooling water systems(CWSs)are extensively utilized in various industries to eliminate the excess heat and converse energy.Studies on CWSs mainly concentrated on finding the optimal cooler network structure.In addition,some works also considered the optimal design under varied operation conditions.However,in these works,once the optimal design of the cooler's network is determined,its arrangement remains fixed and cannot be adapted to accommodate diverse operating conditions.In this work,a flexible topology network concept is proposed to make the adjustment of network structure possible under different operation conditions.The CWS with integrated air cooler and flexible topology network has better overall performance,represented by a mixed integer nonlinear programming(MINLP)model that require advanced tools such as GAMS software.Case studies revealed that the proposed methodology can realize better energy-saving performance,and improve the economic performance under varied operation conditions.The impact of critical flexible nodes on system configuration and economy is achieved by sensitivity analysis.展开更多
Cross-border e-commerce(CBEC)significantly stimulates foreign trade development and the flow of goods and services.This study,using Chinese city-level data and a multiperiod difference-in-differences model based on CB...Cross-border e-commerce(CBEC)significantly stimulates foreign trade development and the flow of goods and services.This study,using Chinese city-level data and a multiperiod difference-in-differences model based on CBEC comprehensive pilot zones,explores the impact of CBEC reform on urban service industry entrepreneurship.The results show that CBEC reform increased entrepreneurial activity,and this is confirmed by robustness tests.The mechanisms driving this efect include the attraction of foreign direct investment,improved information infrastructure,and talent development.Regional analysis reveals stronger effects in central,western,and noncoastal cities,and industry analysis highlights public and consumer services.Spatial heterogeneity shows that the reform's impact diminished with distance from pilot zones,with potential inhibitory efects in remote areas.This study demonstrates how CBEC reform can stimulate entrepreneurship and foster economicgrowth.展开更多
Cross-regional allocation is necessary for the rational utilization and optimal allocation of resources.It is also the key to effective and sustainable disaster relief.Existing research,however,generally centers on em...Cross-regional allocation is necessary for the rational utilization and optimal allocation of resources.It is also the key to effective and sustainable disaster relief.Existing research,however,generally centers on emergency resource allocation only within territories or regions.This article proposes a multiperiod allocation optimization model for emergency resources based on regional selfrescue and cross-regional collaborative rescue efforts.The model targets the shortest delivery time and lowest allocation costs as its efficiency goals and the maximum coverage rate of resource allocation in the disaster-affected locations as its equity goal.An objective weighting fuzzy algorithm based on two-dimensional Euclidean distance is designed to solve the proposed model.A case study based on the Wenchuan Earthquake of 12 May 2008 was conducted to validate the proposed model.The results indicate that our proposed model allows for optimal,multiperiod cross-regional resource allocation by combining interterritorial and nearby allocation principles.Cross-regional relief makes resource allocation more equitable,minimizes dissatisfaction,and prevents losses.Different decision preferences appear to significantly affect the choice of resource allocation scheme employed,which provides flexibility for decision making in different emergencies.展开更多
Consider a sequence of markets for goods and securities at successive dates, each market is a hybrid of plan and market, no one of which is complete in Arrow\|Debreu sense. Pseudo\|equilibrium and equilibrium of s...Consider a sequence of markets for goods and securities at successive dates, each market is a hybrid of plan and market, no one of which is complete in Arrow\|Debreu sense. Pseudo\|equilibrium and equilibrium of such an economic model are introduced and the existence of which is demonstrated.展开更多
This study aims to solve the problem of multiproduct multiperiod integrated transportation and inventory optimization for online retailers.A carbon cap constraint and multitype of capacitated trucks are simultaneously...This study aims to solve the problem of multiproduct multiperiod integrated transportation and inventory optimization for online retailers.A carbon cap constraint and multitype of capacitated trucks are simultaneously incorporated into the proposed mixed-integer program.A simulated annealing(SA)algorithm is designed.CPLEX 12.9.0 is used to solve the submodel obtained from the neighbourhood search and is also used to get the optimal solutions for instances.Experimental results show that the simulated annealing algorithm can find satisfactory solutions within a reasonable time.When the problem size increases,the growth of the computational time of the SA algorithm is significantly smaller than that of the CPLEX.A sensitivity analysis for the carbon cap is also conducted.The results indicate that if the carbon cap is gradually tightened,the total cost increases first with a gentle slope,and then with a remarkable slope,same as for the total number of trucks used;the total carbon emissions first decrease with a gentle slope,and then decline with a significant slope.When the carbon cap is strict,only a few different types of trucks will be considered.The percentage changes of the total cost increase and the total carbon emission reduction are also compared.When the allowed carbon emissions are gradually reduced,situation of a higher amount of carbon emission reduction and a lower amount of cost increase can be achieved.Additionally,using multiple types of trucks in the integrated optimization of transportation and inventory decisions can achieve greater cost savings with lower increments of carbon emission.展开更多
In times of increasing global warming,enormous efforts are required to rapidly reduce greenhouse gas(GHG)emissions.Due to the EU’s target of climate neutrality by 2050 and the even more ambitious goal of becoming cli...In times of increasing global warming,enormous efforts are required to rapidly reduce greenhouse gas(GHG)emissions.Due to the EU’s target of climate neutrality by 2050 and the even more ambitious goal of becoming climate-neutral in Germany by 2045,it is necessary to systematically increase energy efficiency and decarbonize the industrial heat sector.The methods of heat integration can be used to exploit existing potentials for waste heat utilization and to integrate renewable technologies for heating and cooling.By using a non-stationary,multiperiod approach,additional energy savings can be achieved by integrating a thermal energy storage(TES)that enables heat transportation over time.This paper presents a simultaneous approach for thermal energy storage integration into multiperiod heat integration problems.The approach can be used to minimize energy demand,costs and CO 2 emissions and is demonstrated in two case studies.In case study 1,it is shown that the presented approach is capable of integrating a TES properly into a simple multiperiod heat integration problem with two periods.In case study 2,a simplified example from a cosmetics manufactory is investigated.The total utility demand can be reduced by up to 44.3%due to TES integration and the energetic optimal storage size can be determined as 125 m 3.The savings are strongly dependent on the constellation of heat flows between the periods,on the temperature levels and on the storage size.Significant reductions of energy demand,costs and CO 2 emissions can be achieved with TES being properly integrated into a suitable operating environment.展开更多
Traditional open circulating cooling water systems use a lot of water and electricity to remove waste heat.In coastal areas,closed seawater circulating cooling water systems have been used as an alternative to improve...Traditional open circulating cooling water systems use a lot of water and electricity to remove waste heat.In coastal areas,closed seawater circulating cooling water systems have been used as an alternative to improve cooling efficiency.However,a comprehensive comparison of the design and advantages of the two types of cooling systems is lacking.Also,the best way to match and optimize the seawater system with the circulating water system in the closed seawater circulating cooling water system has not been fully explored.In this paper,a closed seawater cooling system under multiperiod is constructed,taking into account monthly changes in environmental factors.The mixed integer nonlinear programming model is solved by using GAMS software to evaluate and compare the economics and operability of the two cooling schemes.Meanwhile,the matching relationship of the internal subsystems of the closed seawater circulating cooling water system after coupling the air coolers is studied in depth,and the cooling load is allocated reasonably.The cases show that seawater cooling saves 9.22%of circulating water and reduces the total cost by 8.93%compared with cooling tower.The cost of the closed seawater cooling system can be reduced by 24.37%after coupling air coolers,and there is a direct corresponding matching relationship between circulating water and seawater.展开更多
文摘A complex autonomous inventory coupled system is considered. It can take, for example, the form of a network of chemical or biochemical reactors, where the inventory interactions perform the recycling of by-products between the subsystems. Because of the flexible subsystems interactions, each of them can be operated with their own periods utilizing advantageously their dynamic properties. A multifrequency second-order test generalizing the p-test for single systems is described. It can be used to decide which kind of the operation (the static one, the periodic one or the multiperiodic one) will intensify the productivity of a complex system. An illustrative example of the multiperiodic optimization of a complex chemical production system is presented.
基金supported by the National Social Science Fund of China[Grant No.21BGL181]to Yan Chen.
文摘Coal dependence and inefficient decentralized heating have significantly increased China’s energy consumption for winter heating,increasing air pollution and exacerbating the greenhouse effect.In 2017,China implemented the Pilot Policy on Clean Winter Heating in Northern China,aiming to achieve high central heating coverage and cleaner energy consumption.Studying the effects of this policy can help promote its implementation and serve as a reference for effective adjustment of the contents in the future.However,few studies have investigated this policy and its carbon reduction effects,and most focus on the provincial or city levels.Therefore,this paper considers the policy’s influence on air pollution and carbon emissions at the county level to provide a precise and comprehensive assessment of the policy effects.We use panel data from 1290 counties in 15 provinces in Northern China from 2014 to 2021,applying a multiperiod difference-in-differences model to quantify the impact of the policy on carbon emissions and air quality in the pilot area.We then conduct a series of tests to demonstrate the robustness of the results and analyze the mechanisms of the policy effects from two perspectives,namely,central heating and natural gas use,through a mediating effect model.Finally,we examine the heterogeneity of policy effects between counties based on geographic location and per capita income levels of rural residents through a moderating effect model.The results reveal that the policy significantly reduces air pollution and carbon emissions in the pilot area by increasing the central heating area and natural gas use.Compared with the central and western regions in the north and areas with low-income rural residents,the policy effects in the eastern regions in the north and areas with high-income rural residents are more pronounced.
基金supported by the Major Project of the National Social Science Fund of China (NSSFC)“Economic Development for Ethnic Minorities under Socialism with Chinese Characteristics and International Comparison”(Grant No. 19ZDA173)the NSSFC Project “Study on the Implementation and Development of Educational Assistance to Xizang and Xinjiang under the Horizon of the Community of the Chinese Nation”(Grant No. CMA220323)the Elite Innovation Team of Pu’er University “Innovation Team for the Prosperity of Border Regions and Common Modernization of Ethnic Minority Regions”(Grant No. 2023PEXYCXTD002)
文摘This study highlights the changing priorities of China’s paired assistance throughout the past decades,as well as its theoretical implications and economic growth effects for recipient regions.Using panel data from 32 prefecture-level cities from 1990 to 2020,this study uses the multiperiod difference-in-differences approach to examine how paired assistance has contributed to economic growth in Xizang Autonomous Region and Xinjiang Uygur Autonomous Region.The findings indicate that,first,the implementation of the paired assistance policy has boosted economic growth in Xizang and Xinjiang.Second,paired assistance has stimulated economic growth in recipient communities by improving infrastructure.Third,paired assistance has contributed to economic growth in recipient communities by providing improved public services such as education and healthcare.Improvements to public services have a relatively smaller indirect effect in short term than infrastructure development on economic growth.Yet both education and healthcare are crucial to people’s quality of life in recipient communities.This paper has refined and broadened research on the effects of paired assistance,providing preference for future policymaking.
文摘The current portfolio model for property-liability insurance company is only single period that can not meet the practical demands of portfolio management, and the purpose of this paper is to develop a multiperiod model for its portfolio problem. The model is a multistage stochastic programming which considers transaction costs, cash flow between time periods, and the matching of asset and liability; it does not depend on the assumption for normality of return distribution. Additionally, an investment constraint is added. The numerical example manifests that the multiperiod model can more effectively assist the property-liability insurer to determine the optimal composition of insurance and investment portfolio and outperforms the single period one.
基金Supported by the National Natural Science Foundation of China(21676211,21878240,21808179)China’s Post-doctoral Science Fund(2018M633518)+1 种基金Key Research and Development Program of Shaanxi Province(2018GY-072)the Fundamental Research Funds for the Central Universities(1191329819)
文摘Dealing with uncertainty is one of practical issues in design and operation of heat exchanger networks(HENs),arising the problem of flexible HEN synthesis.This paper addresses the state-of-the-art methods for flexible HEN synthesis based on sensitivity analysis,resilience analysis,flexibility analysis and multiperiod synthesis techniques as well.Each of these methods is summarized by presenting their general procedures and recent developments on modeling,solving strategies and applications.Some current topics related to flexible process synthesis have been briefly presented to provide several future research possibilities.
基金The first,second,and fifth authors acknowledge the financial support provided by the National Natural Science Foundation of China(41672133)The second author also acknowledges the National Natural Science Foundation of China(4207021285).
文摘The cumulative expression of multistage deformation is complex multiperiod fractures,which are commonly seen in tectonic zones.The Middle Triassic Leikoupo Formation in the western Sichuan Basin Depression,China,is a typical marine carbonate reservoir with natural fractures caused mainly by tectonic movements.According to outcrops,drill cores,image logging,and fluid inclusions,the fracture characteristics,types of natural fractures,and interactions of fractures are determined.In total,419 natural fractures in 493.2 m of cores from 7 wells are investigated,which are mainly shear and tensile fractures with a small number of weathering generated fractures.Meanwhile,the results of the stable isotope analysis of δ13C and δ18O,as well as the flow fluid inclusion data,reveal four tectonic periods of fractures with different occurrences.Based on the history of regional tectonic evolution,indicating one period of weathering fractures ascribable to stratal uplift and three periods of structural fractures related to the sequential tectonic movements of the Longmenshan fault belt.By analyzing the interaction relationships of fractures,three types of fracture interaction relationships are observed:cutting,restraining,and overlapping.The four stages fractures are chronologically assigned to(1)the early Indosinian N-S trending compression,(2)the late Indosinian NW-SE compression,(3)the middle Yanshanian NE-SE compression,and(4)the early Himalayan E-W compression.The influence of natural fractures on gas migration and well production in marine carbonates is discussed,and indicates that tectonic fractures could provide seepage channels for gas migration and accumulation from near or distant hydrocarbon source rocks into the Middle Triassic Leikoupo Formation.This study utilizes a pragmatic approach for understanding the fracture genesis mechanism in oil and gas field with multiperiod fractures.
基金Financial support from the National Natural Science Foundation of China under Grant(Nos.22022816 and 22078358)
文摘Cooling water systems(CWSs)are extensively utilized in various industries to eliminate the excess heat and converse energy.Studies on CWSs mainly concentrated on finding the optimal cooler network structure.In addition,some works also considered the optimal design under varied operation conditions.However,in these works,once the optimal design of the cooler's network is determined,its arrangement remains fixed and cannot be adapted to accommodate diverse operating conditions.In this work,a flexible topology network concept is proposed to make the adjustment of network structure possible under different operation conditions.The CWS with integrated air cooler and flexible topology network has better overall performance,represented by a mixed integer nonlinear programming(MINLP)model that require advanced tools such as GAMS software.Case studies revealed that the proposed methodology can realize better energy-saving performance,and improve the economic performance under varied operation conditions.The impact of critical flexible nodes on system configuration and economy is achieved by sensitivity analysis.
基金support from the National Natural Science Foundation of China (No.72341014).
文摘Cross-border e-commerce(CBEC)significantly stimulates foreign trade development and the flow of goods and services.This study,using Chinese city-level data and a multiperiod difference-in-differences model based on CBEC comprehensive pilot zones,explores the impact of CBEC reform on urban service industry entrepreneurship.The results show that CBEC reform increased entrepreneurial activity,and this is confirmed by robustness tests.The mechanisms driving this efect include the attraction of foreign direct investment,improved information infrastructure,and talent development.Regional analysis reveals stronger effects in central,western,and noncoastal cities,and industry analysis highlights public and consumer services.Spatial heterogeneity shows that the reform's impact diminished with distance from pilot zones,with potential inhibitory efects in remote areas.This study demonstrates how CBEC reform can stimulate entrepreneurship and foster economicgrowth.
基金supported by the Postdoctoral Science Foundation of China Grant Nos.2020M670363,2020T130340the National Natural Science Foundation of China Grant Nos.71790611,71774042the Humanities and Social Sciences of the Ministry of Education of China Grant No.20YJC630243。
文摘Cross-regional allocation is necessary for the rational utilization and optimal allocation of resources.It is also the key to effective and sustainable disaster relief.Existing research,however,generally centers on emergency resource allocation only within territories or regions.This article proposes a multiperiod allocation optimization model for emergency resources based on regional selfrescue and cross-regional collaborative rescue efforts.The model targets the shortest delivery time and lowest allocation costs as its efficiency goals and the maximum coverage rate of resource allocation in the disaster-affected locations as its equity goal.An objective weighting fuzzy algorithm based on two-dimensional Euclidean distance is designed to solve the proposed model.A case study based on the Wenchuan Earthquake of 12 May 2008 was conducted to validate the proposed model.The results indicate that our proposed model allows for optimal,multiperiod cross-regional resource allocation by combining interterritorial and nearby allocation principles.Cross-regional relief makes resource allocation more equitable,minimizes dissatisfaction,and prevents losses.Different decision preferences appear to significantly affect the choice of resource allocation scheme employed,which provides flexibility for decision making in different emergencies.
文摘Consider a sequence of markets for goods and securities at successive dates, each market is a hybrid of plan and market, no one of which is complete in Arrow\|Debreu sense. Pseudo\|equilibrium and equilibrium of such an economic model are introduced and the existence of which is demonstrated.
文摘This study aims to solve the problem of multiproduct multiperiod integrated transportation and inventory optimization for online retailers.A carbon cap constraint and multitype of capacitated trucks are simultaneously incorporated into the proposed mixed-integer program.A simulated annealing(SA)algorithm is designed.CPLEX 12.9.0 is used to solve the submodel obtained from the neighbourhood search and is also used to get the optimal solutions for instances.Experimental results show that the simulated annealing algorithm can find satisfactory solutions within a reasonable time.When the problem size increases,the growth of the computational time of the SA algorithm is significantly smaller than that of the CPLEX.A sensitivity analysis for the carbon cap is also conducted.The results indicate that if the carbon cap is gradually tightened,the total cost increases first with a gentle slope,and then with a remarkable slope,same as for the total number of trucks used;the total carbon emissions first decrease with a gentle slope,and then decline with a significant slope.When the carbon cap is strict,only a few different types of trucks will be considered.The percentage changes of the total cost increase and the total carbon emission reduction are also compared.When the allowed carbon emissions are gradually reduced,situation of a higher amount of carbon emission reduction and a lower amount of cost increase can be achieved.Additionally,using multiple types of trucks in the integrated optimization of transportation and inventory decisions can achieve greater cost savings with lower increments of carbon emission.
文摘In times of increasing global warming,enormous efforts are required to rapidly reduce greenhouse gas(GHG)emissions.Due to the EU’s target of climate neutrality by 2050 and the even more ambitious goal of becoming climate-neutral in Germany by 2045,it is necessary to systematically increase energy efficiency and decarbonize the industrial heat sector.The methods of heat integration can be used to exploit existing potentials for waste heat utilization and to integrate renewable technologies for heating and cooling.By using a non-stationary,multiperiod approach,additional energy savings can be achieved by integrating a thermal energy storage(TES)that enables heat transportation over time.This paper presents a simultaneous approach for thermal energy storage integration into multiperiod heat integration problems.The approach can be used to minimize energy demand,costs and CO 2 emissions and is demonstrated in two case studies.In case study 1,it is shown that the presented approach is capable of integrating a TES properly into a simple multiperiod heat integration problem with two periods.In case study 2,a simplified example from a cosmetics manufactory is investigated.The total utility demand can be reduced by up to 44.3%due to TES integration and the energetic optimal storage size can be determined as 125 m 3.The savings are strongly dependent on the constellation of heat flows between the periods,on the temperature levels and on the storage size.Significant reductions of energy demand,costs and CO 2 emissions can be achieved with TES being properly integrated into a suitable operating environment.
基金support from the National Natural Science Foundation of China under Grant(Grant Nos.22393954 and 22078358)is gratefully acknowledged.
文摘Traditional open circulating cooling water systems use a lot of water and electricity to remove waste heat.In coastal areas,closed seawater circulating cooling water systems have been used as an alternative to improve cooling efficiency.However,a comprehensive comparison of the design and advantages of the two types of cooling systems is lacking.Also,the best way to match and optimize the seawater system with the circulating water system in the closed seawater circulating cooling water system has not been fully explored.In this paper,a closed seawater cooling system under multiperiod is constructed,taking into account monthly changes in environmental factors.The mixed integer nonlinear programming model is solved by using GAMS software to evaluate and compare the economics and operability of the two cooling schemes.Meanwhile,the matching relationship of the internal subsystems of the closed seawater circulating cooling water system after coupling the air coolers is studied in depth,and the cooling load is allocated reasonably.The cases show that seawater cooling saves 9.22%of circulating water and reduces the total cost by 8.93%compared with cooling tower.The cost of the closed seawater cooling system can be reduced by 24.37%after coupling air coolers,and there is a direct corresponding matching relationship between circulating water and seawater.
