Total site heat integration(TSHI) provides more opportunities for energy saving in industry clusters. Some design methods including direct integration using process streams and indirect integration using intermediate-...Total site heat integration(TSHI) provides more opportunities for energy saving in industry clusters. Some design methods including direct integration using process streams and indirect integration using intermediate-fluid circuits, i.e., steam, dowtherms and hot water, have been proposed during last few decades. Indirect heat integration is preferred when the heat sources and sinks are separated in independent plants with rather long distance. This improves energy efficiency by adaption of intermediate fluid circle which acts as a utility provider for plants in a symbiotic network. However, there are some significant factors ignored in conventional TSHI, i.e. the investment of pipeline, cost of pumping and heat loss. These factors simultaneously determine the possibility and performance of heat integration. This work presents a new methodology for indirect heat integration in low temperature range using hot water circuit as intermediate-fluid medium. The new methodology enables the targeting of indirect heat integration across plants considering the factors mentioned earlier. An MINLP model with economic objective is established and solved. The optimization results give the mass flow rate of intermediate-fluid, diameter of pipeline, the temperature of the circuits and the matches of heat exchanger networks(HENS) automatically. Finally, the application of this proposed methodology is illustrated with a case study.展开更多
This paper presents a description and analysis of the most important models to predict each of the Road User Costs components （Vehicle Operating Costs, Accident Costs and Value of Time） and proposes a model for esti...This paper presents a description and analysis of the most important models to predict each of the Road User Costs components （Vehicle Operating Costs, Accident Costs and Value of Time） and proposes a model for estimating RUC components suitable for the Portuguese road network. These results are part of a research which aimed to obtain a Road User Cost Model to be used as a tool in road management systems. This model is different from other models by the fact that it includes a simple formulation that allows calibration and calculation of cost parameters, for any year, in a simple and fast way, providing trustworthy results. The required data is already available in Portuguese institutions, allowing periodic revision of cost parameters to insure accuracy.展开更多
A SN （structural number） can be calculated for a road pavement from the properties and thicknesses of the surface, basecourse, sub-base and subgrade. Historically, the cost of collecting structural data has been ver...A SN （structural number） can be calculated for a road pavement from the properties and thicknesses of the surface, basecourse, sub-base and subgrade. Historically, the cost of collecting structural data has been very high. Data was initially collected using Benkelman Beams and now by FWD （falling weight deflectometer）. The structural strength of pavements weakens over time due to environmental and traffic loading factors but due to a lack of data, no structural deterioration curve for pavements has been implemented in a PMS （pavement management system）. IRI （international roughness index） is a measure of the road longitudinal profile and has been used as a proxy for a pavement’s structural integrity. This paper offers two conceptual methods to develop PSDC （pavement structural deterioration curves）. Firstly, structural data are grouped in sets by design ESA （equivalent standard axles）. An ISN （“initial” SN）, SNI （intermediate SN） and a TSN （terminal SN）, are used to develop the curves. Using FWD data, the ISN is the SN after the pavement is rehabilitated （Financial Accounting “Modern Equivalent”）. Intermediate SNIs, are SNs other than the ISN and TSN. The TSN was defined as the SN of the pavement when it was approved for pavement rehabilitation. The second method is to use TSD （traffic speed deflectometer） data. The road network already divided into road blocks, is grouped by traffic loading. For each traffic loading group, road blocks that have had a recent pavement rehabilitation, are used to calculate the ISN and those planned for pavement rehabilitation to calculate the TSN. The remaining SNs are used to complete the age-based or if available, historical traffic loading-based SNIs.展开更多
This paper proposes a simple low cost SIR （sustainability index for roads） that can be easily implemented by any local government that has a flexible pavement road network. The SIR includes the three pillars of sust...This paper proposes a simple low cost SIR （sustainability index for roads） that can be easily implemented by any local government that has a flexible pavement road network. The SIR includes the three pillars of sustainability, economic, social and environmental. The economic pillar is development from a new perspective of pavement deterioration from the Snowy Mountains Engineering Corporation＇s Pavement Management System. The new perspective is easily seen when the deterioration is plotted in three dimensions. This new exponential curve provides an equation for the return on investment in a road network, in terms of a future pavement condition index versus the annual rehabilitation budget. The environmental pillar will be developed by determining which road rehabilitation treatments cause the most environmental damage and recreating the new curve with these treatments being incrementally removed. The resulting curves will provide the annual cost of minimizing environmental damage and the loss of pavement condition index for minimizing environmental damage. The social pillar is, consultation with the community on what pavement condition index they are willing to fund, that is, balancing annual cost, environmental damage and desired pavement condition. This more efficient reporting conforms with the USA Government Accounting Standards Board requirements but not necessarily with the International Financial Reporting Standards. This new SIR reduces the current financial reporting requirement for local govemments in Queensland, Australia and can greatly improve comparability of financial reporting, where local governments calibrate the pavement deterioration factors in their Pavement Management Systems and use the newly developed regional rulebase.展开更多
Systematic approach to the maintenance of rural road network is a very important issue from the viewpoint of public costs. Most countries developed custom PMS （pavement management systems） based on deterministic or ...Systematic approach to the maintenance of rural road network is a very important issue from the viewpoint of public costs. Most countries developed custom PMS （pavement management systems） based on deterministic or probabilistic approach. The main goal is to ensure safety and continuity of road traffic on road network with low intensity and lower technical requirements. Article presents PMS used for Slovakia rural road network based on road construction diagnostics, traffic volume, climate factors and evaluation of maintenance works economics effectives by using of software tools like HDM-4 developed by World Bank. Local road administrators of rural road networks often lack the software equipment, most PMS, however effective, are often cumbersome, demanding in regard to energy, know-how and software equipment. The majority of local road administrators of rural road networks thus resort to non-effective reactive maintenance strategies. This article describes an easy to use method, based on predetermined maintenance repair and rehabilitation standards. A simple method, based on road user cost, is introduced that administrator can use to prepare a list of road section eligible for repair according to their repair priority.展开更多
基金Supported by the National Basic Research Program of China(2012CB720500)the National Natural Science Foundation of China(21476256)
文摘Total site heat integration(TSHI) provides more opportunities for energy saving in industry clusters. Some design methods including direct integration using process streams and indirect integration using intermediate-fluid circuits, i.e., steam, dowtherms and hot water, have been proposed during last few decades. Indirect heat integration is preferred when the heat sources and sinks are separated in independent plants with rather long distance. This improves energy efficiency by adaption of intermediate fluid circle which acts as a utility provider for plants in a symbiotic network. However, there are some significant factors ignored in conventional TSHI, i.e. the investment of pipeline, cost of pumping and heat loss. These factors simultaneously determine the possibility and performance of heat integration. This work presents a new methodology for indirect heat integration in low temperature range using hot water circuit as intermediate-fluid medium. The new methodology enables the targeting of indirect heat integration across plants considering the factors mentioned earlier. An MINLP model with economic objective is established and solved. The optimization results give the mass flow rate of intermediate-fluid, diameter of pipeline, the temperature of the circuits and the matches of heat exchanger networks(HENS) automatically. Finally, the application of this proposed methodology is illustrated with a case study.
文摘This paper presents a description and analysis of the most important models to predict each of the Road User Costs components （Vehicle Operating Costs, Accident Costs and Value of Time） and proposes a model for estimating RUC components suitable for the Portuguese road network. These results are part of a research which aimed to obtain a Road User Cost Model to be used as a tool in road management systems. This model is different from other models by the fact that it includes a simple formulation that allows calibration and calculation of cost parameters, for any year, in a simple and fast way, providing trustworthy results. The required data is already available in Portuguese institutions, allowing periodic revision of cost parameters to insure accuracy.
文摘A SN （structural number） can be calculated for a road pavement from the properties and thicknesses of the surface, basecourse, sub-base and subgrade. Historically, the cost of collecting structural data has been very high. Data was initially collected using Benkelman Beams and now by FWD （falling weight deflectometer）. The structural strength of pavements weakens over time due to environmental and traffic loading factors but due to a lack of data, no structural deterioration curve for pavements has been implemented in a PMS （pavement management system）. IRI （international roughness index） is a measure of the road longitudinal profile and has been used as a proxy for a pavement’s structural integrity. This paper offers two conceptual methods to develop PSDC （pavement structural deterioration curves）. Firstly, structural data are grouped in sets by design ESA （equivalent standard axles）. An ISN （“initial” SN）, SNI （intermediate SN） and a TSN （terminal SN）, are used to develop the curves. Using FWD data, the ISN is the SN after the pavement is rehabilitated （Financial Accounting “Modern Equivalent”）. Intermediate SNIs, are SNs other than the ISN and TSN. The TSN was defined as the SN of the pavement when it was approved for pavement rehabilitation. The second method is to use TSD （traffic speed deflectometer） data. The road network already divided into road blocks, is grouped by traffic loading. For each traffic loading group, road blocks that have had a recent pavement rehabilitation, are used to calculate the ISN and those planned for pavement rehabilitation to calculate the TSN. The remaining SNs are used to complete the age-based or if available, historical traffic loading-based SNIs.
文摘This paper proposes a simple low cost SIR （sustainability index for roads） that can be easily implemented by any local government that has a flexible pavement road network. The SIR includes the three pillars of sustainability, economic, social and environmental. The economic pillar is development from a new perspective of pavement deterioration from the Snowy Mountains Engineering Corporation＇s Pavement Management System. The new perspective is easily seen when the deterioration is plotted in three dimensions. This new exponential curve provides an equation for the return on investment in a road network, in terms of a future pavement condition index versus the annual rehabilitation budget. The environmental pillar will be developed by determining which road rehabilitation treatments cause the most environmental damage and recreating the new curve with these treatments being incrementally removed. The resulting curves will provide the annual cost of minimizing environmental damage and the loss of pavement condition index for minimizing environmental damage. The social pillar is, consultation with the community on what pavement condition index they are willing to fund, that is, balancing annual cost, environmental damage and desired pavement condition. This more efficient reporting conforms with the USA Government Accounting Standards Board requirements but not necessarily with the International Financial Reporting Standards. This new SIR reduces the current financial reporting requirement for local govemments in Queensland, Australia and can greatly improve comparability of financial reporting, where local governments calibrate the pavement deterioration factors in their Pavement Management Systems and use the newly developed regional rulebase.
文摘Systematic approach to the maintenance of rural road network is a very important issue from the viewpoint of public costs. Most countries developed custom PMS （pavement management systems） based on deterministic or probabilistic approach. The main goal is to ensure safety and continuity of road traffic on road network with low intensity and lower technical requirements. Article presents PMS used for Slovakia rural road network based on road construction diagnostics, traffic volume, climate factors and evaluation of maintenance works economics effectives by using of software tools like HDM-4 developed by World Bank. Local road administrators of rural road networks often lack the software equipment, most PMS, however effective, are often cumbersome, demanding in regard to energy, know-how and software equipment. The majority of local road administrators of rural road networks thus resort to non-effective reactive maintenance strategies. This article describes an easy to use method, based on predetermined maintenance repair and rehabilitation standards. A simple method, based on road user cost, is introduced that administrator can use to prepare a list of road section eligible for repair according to their repair priority.
