Carbon efficiency evaluation method for urban energy system with multiple energy complementary

Urban energy systems(UESs)play a pivotal role in the consumption of clean energy and the promotion of energy cascade utilization.In the context of the construction and operation strategy of UESs with multiple complementary energy resources,a comprehensive assessment of the energy efficiency is of paramount importance.First,a multi-dimensional evaluation system with four primary indexes of energy utilization,environmental protection,system operation,and economic efficiency and 21 secondary indexes is constructed to comprehensively portray the UES.Considering that the evaluation system may contain a large number of indexes and that there is overlapping information among them,an energy efficiency evaluation method based on data processing,dimensionality reduction,integration of combined weights,and gray correlation analysis is proposed.This method can effectively reduce the number of calculations and improve the accuracy of energy efficiency assessments.Third,a demonstration project for a UES in China is presented.The energy efficiency of each scenario is assessed using six operational scenarios.The results show that Scenario 5,in which parks operate independently and investors build shared energy-storage equipment,has the best results and is best suited for green and low-carbon development.The results of the comparative assessment methods show that the proposed method provides a good energy efficiency assessment.This study provides a reference for the optimal planning,construction,and operation of UESs with multiple energy sources.

A Geodesign Method of Human-Energy-Water Interactive Systems for Urban Infrastructure Design： 10KM2 Near-Zero District Project in Shanghai

The grand challenges of climate change demand a new paradigm of urban design that takes the perfor- mance of urban systems into account, such as energy and water efficiency. Traditional urban design methods focus on the form-making process and lack performance dimensions. Geodesign is an emerging approach that emphasizes the links between systems thinking, digital technology, and geographic con- text. This paper presents the research results of the first phase of a larger research collaboration and pro- poses an extended geodesign method for a district-scale urban design to integrate systems of renewable energy production, energy consumption, and storm water management, as well as a measurement of human experiences in cities. The method incorporates geographic information system （GIS）, parametric modeling techniques, and multidisciplinary design optimization （MDO） tools that enable collaborative design decision-making. The method is tested and refined in a test case with the objective of designing a near-zero-energy urban district. Our final method has three characteristics. （1） Integrated geodesign and parametric design： It uses a parametric design approach to generate focal-scale district prototypes by means of a custom procedural algorithm, and applies geodesign to evaluate the performances of design proposals. （2） A focus on design flow： It elaborates how to define problems, what information is selected, and what criteria are used in making design decisions. （3） Multi-objective optimization： The test case produces indicators from performance modeling and derives principles through a multi-objective computational experiment to inform how the design can be improved. This paper concludes with issues and next steps in modeling urban design and infrastructure systems based on MDO tools.

Field Test of Energy Storage System on Urban Transit System

The energy storage system charges the energy generated during braking and discharges it again when a vehicle accelerates on urban transit system. The energy storage system is considered to be one of the useful devices for energy storing and recycling. The energy storage system was developed and installed on the test track of Gyeongsan LRT in Korea. This paper presents the test plan and how much energy is saved by the energy storage system through the field test. When the energy storage system is on/off, the energy saving rate is obtained.

ENERGY ASSESSMENT OF URBAN BUILDINGS BASED ON GEOGRAPHIC INFORMATION SYSTEM

Urban building energy analysis has attracted more attention as the population living in cities increases as does the associated energy consumption in urban environments.This paper proposes a systematic bottom-up method to conduct energy analysis and assess energy saving potentials by combining dynamic engineering-based energy models,machine learning models,and global sensitivity analysis within the GIS(Geographic Information System)environment for large-scale urban buildings.This method includes five steps:database construction of building parameters,automation of creating building models at the GIS environment,construction of machine learning models for building energy assessment,sensitivity analysis for choosing energy saving measures,and GIS visual evaluation of energy saving schemes.Campus buildings in Tianjin(China)are used as a case study to demonstrate the application of the method proposed in this research.The results indicate that the method proposed here can provide reliable and fast analysis to evaluate the energy performance of urban buildings and determine effective energy saving measures to reduce energy consumption of urban buildings.Moreover,the GIS-based analysis is very useful to both create energy models of buildings and display energy analysis results for urban buildings.

Contrasting Characteristics of the Surface Energy Balance between the Urban and Rural Areas of Beijing

A direct comparison of urban and rural surface energy balances, as well as a variety of other variables including incoming shortwave/longwave radiation and aerosol optical depth, is conducted for the Beijing metropolitan area. The results indicate that, overall, the urban area receives a smaller amount of incoming shortwave radiation but a larger amount of incoming longwave radiation. However, comparisons in the aerosol optical depth and cloud fraction at the two locations suggest that neither aerosol optical depth nor cloud fraction alone can explain the difference in the incoming shortwave radiation. The urban–rural differences in the incoming longwave radiation are unlikely to be caused by the presence of more abundant greenhouse gases over the urban area, as suggested by some previous studies, given that water vapor is the most dominant greenhouse gas and precipitable water is found to be less in urban areas. The higher incoming longwave radiation observed over the urban area is mostly likely due to the higher temperatures of the ambient air. The urban area is also found to always produce higher sensible heat fluxes and lower latent heat fluxes in the growing season. Furthermore, the urban area is associated with a larger amount of available energy（the sum of sensible and latent heat fluxes） than the rural area, except in May and October when evapotranspiration in the rural area significantly exceeds that in the urban area. This study provides observational evidence of urban–rural contrasts in relevant energy-balance components that plausibly arise from urban–rural differences in atmospheric and land-surface conditions.

Sustainable urbanization: energy and environment in the Chongqing Municipality, China

Chongqing is the largest municipality under the Chinese Central Government (MCG) in terms of administrative area and population and is now the most important economic and cultural center of the upper Yangtze River and Three Gorges area. The Three Gorges Dam project, one of the largest world infrastructure projects, causes a great deal of immigration to Chongqing and results in the rapid urbanization of the city, and it has brought in a great deal of environmental impact, which is a global concerned issue. This paper introduces the city profile of Chongqing municipality and its urbanization impact on energy and environment. The demand and the trend of energy consumption in built environment (building and transport) have been analysed. The living environment of Chongqing residents and the local energy efficient policy have been introduced. Finally the authors discuss the key issues of the sustainable urban development of Chongqing.

DEVELOPMENT OF THE ENERGY MANAGEMENT STRATEGY FOR PARALLEL HYBRID ELECTRIC URBAN BUSES

A novel parallel hybrid electrical urban bus （PHEUB） configuration consisting of an extra one-way clutch and an automatic mechanical transmission （AMT） is taken as the study subject. An energy management strategy combining a logic threshold approach and an instantaneous optimization algorithm is proposed for the investigated PHEUB. The objective of the energy management strategy is to achieve acceptable vehicle performance and drivability requirements while simultaneously maximizing the engine fuel consumption and maintaining the battery state of charge in its operation range at all times. Under the environment of Matlab/Simulink, a computer simulation model for the PHEUB is constructed by using the model building method combining theoretical analysis and bench test data. Simulation and experiment results for China Typical Bus Driving Schedule at Urban District （CTBDS_UD） are obtained, and the results indicate that the proposed control strategy not only controls the hybrid system efficiently but also improves the fuel economy significantly.

Energy management and coordination control of microgrid in elevated station of urban rail transit

The rapid development of urban rail transit brings convenience to the public,but its huge energy consumption problem cannot be ignored.A microgrid composed of photovoltaic power generation unit,regenerative braking energy feedback unit and battery energy storage unit is proposed,which provides green power for the station.In order to suppress the fluctuation of photovoltaic power generation and the intermittence of regenerative braking feedback energy,the energy management mode of microgrid is designed according to the illumination situation,braking energy feedback situation,battery state of charge and so on.In addition,a coordination control method based on virtual synchronous generator(VSG)is proposed to realize smooth switching among modes.Finally,the proposed energy management and coordination control method for elevated station microgrid is verified by Matlab/Simulink.The results show that the elevated station microgrid can operate safely and reliably under various energy management modes and realize smooth switching among modes.

Calculation and decomposition of regional household energy consumption in China:based on perspectives of urbanization and residents' consumption

Demographic urbanization caused great changes in scale of residents' consumption and residents' lifestyle and then impacted changes of regional household energy consumption. This paper expanded Logarithmic Mean Decomposition Index method through introducing variables of urbanization and residential consumption into the model. It also analyzed the influences of six factors as energy structure, energy intensity, population scale, urbanization, residential consumption, and consumption inhibit on regional household energy consumption. Results showed that in 2003-2012, impact of urbanization on regional household energy consumption of Chinese three areas was significantly higher than population size. The "population gathered in eastern region" phenomenon caused eastern region getting the largest population scale effect. Driving force of residential consumption on regional household energy consumption was much higher than the other five effects. Due to the comparative advantage of residential consumption compared with government consumption, investment, and net export, the decrease of consumption ratio promoted the growth of regional household energy consumption. Energy intensity in Chinese three regions kept reducing in 2003-2012. The progress of energy utilization technology slowed the growth of regional household energy consumption, and energy intensity effect was most significant in the central region.

Study on Braking Energy Regeneration System for City Bus

Braking of the urban vehicles of public service wastes a large number of engine energy in the condition of starting and stopping frequently. Aiming at the problem, an electro-mechanical braking energy regeneration system was proposed which adopted a high-speed flywheel and a battery to recover the braking energy and achieve the secondary traction for the auxiliary start function. The system strategy was designed and the braking simulation was processed to validate its feasibility. The experiment results show that the system can effectively recover the braking energy, improve the starting performance of the city bus and it can be applied to the engineering.

Energy Planning: Brazilian Potential of Generation of Electric Power from Urban Solid Wastes—Under “<i>Waste Production Liturgy</i>” Point of View

The use of Urban Solid Waste (USW) as sources of energy has acquired rising importance in current discussions of alternative energy supplies, in particular in Brazil. This paper brings to these discussions an examination of the concept of solid wastes, including their historic origins and formation, taking their social, economic and cultural characteristics into account, including point view of waste production liturgy. Consequently, a spendthrift society slanted towards the decreasing marginal utility of assets must make efficient use of its USW in order to reduce excessive output. Besides that, this document presents the Brazilian potential of urban solid waste to produce electric power.

Developing web-based urban energy environmental database

Unbalanced energy consumption distribution caused by the concentration of facilities and population topples the natural energy equilibrium of a city and causes environmental problems such as urban tropical night,heat island phenomenon,global warming deterioration.Therefore,to secure eco-friendliness and sustainability of a city,it is necessary to introduce measures to alleviate the unequal distribution phenomenon of urban energy consumption from the city planning stage.For this purpose,the first step is to understand the current energy environment.The urban energy environment is affected by many factors in addition to gathering of buildings.Therefore,there is a limit to fully understanding advanced urban energy environment with only simple statistical urban information management technique.Research on methods of analyzing urban energy environment through simulation of recent urban scale is underway.There is not enough discussion about basic informaion databases for environmental analysis simulation of urban energy.This study presents a method using GIS(geographic information system) and web-based environmental information database as a way to improve the simulation accuracy.First,environmental information factors used for urban simulation were derived,and a web-based environmental information database targeting Daegu metropolitan city of Korea was built.Then,the urban energy environment was analyzed on a trial basis by linking the database with GIS.

Evaluating the Nexus between Housing and Energy Sectors: The Comparison of Urban, Peri-Urban and Rural Housing Areas in Zhuhai, China

China has developed several housing policy reforms and has, in recent years, progressed further on developing policies to promote green strategies and energy-saving plans. The urban housing has much benefited from such reforms and plans, while rural housing has experienced minimal change in the past few decades. As a result, this study aims to identify and explore these differences, challenges, and implications that exist between three areas of urban, peri-urban, and rural in a particular case study in China. For this study, selected residential areas in the City of Zhuhai and its peri-urban and rural areas are selected as case studies. A questionnaire survey is conducted to analyze energy and housing conditions across the more prosperous urban, the dynamic and transitory peri-urban, and the less prosperous rural areas. The case studies are analyzed as comparative examples in a hot and humid sub-tropical area of Southern China. The study compares energy and housing conditions and argues potential possibilities and challenges for the future development of housing policy reforms that are the result of current housing development patterns and green strategy situation in China.

The Influence of Urbanization on Cooling Energy Consumption in Xi＇an

Based on data of daily air temperature during 1951-2013,long-term variation characteristics of cooling degree days（ CDD） in Xi＇an and Chang＇an in summer were analyzed by using CDD to evaluate cooling energy consumption and 26 ℃ as the basic temperature of CDD. The results indicated that the changing trends of CDD in Xi＇an and Chang＇an were basically identical within a year,and the demand for cooling refrigeration was large mainly from June to August,especially in July. The maximum of urban-rural difference of CDD between Xi＇an and Chang＇an appeared in June.In order to achieve the same temperature,energy needed by the urban area was 5-7 ℃·d more than the suburb from June to August. Temperature and the cooling energy consumption were closely related,and the correlation degree increased with the rise of temperature. The effects of temperature increase of 1 ℃ on cooling energy consumption rate in Xi＇an were more obvious than that in Chang＇an. In both Xi＇an and Chang＇an,the effects of temperature increase of 1 ℃ on cooling energy consumption rate in July and August were greater than that in May,June and September.Evaluation models of cooling energy consumption in summer in Xi＇an and Chang＇an were built using temperature anomaly and CDD variability and can be applied to business systems.

The Relationship between Urbanization and Domestic Energy Consumption:An Empirical Study of Shandong Province,China

The rapid development of urbanization has led to a rapid increase in total energy consumption.The proportion of domestic energy consumption to total energy consumption has gradually increased and has become the major driving force for energy consumption.With the pressure from urbanization and domestic energy consumption,it is necessary to study the impact of urbanization on domestic energy consumption of the regional level and to explore the function paths of these two factors.The findings are helpful to realize sustainable development based on the actual situation analysis,horizontal survey data and statistical yearbook panel data.The current situation and changing trends in domestic energy consumption of Shandong Province are systematically examined through field investigation and survey questionnaire.The time-series econometric model is applied to analyze the relationship between urbanization rate and total domestic energy consumption.The research results show that the total domestic energy consumption and urbanization rate of Shandong are generally increasing.The urbanization rate development and domestic energy consumption have a long-term stable and balanced relationship.An increase in urbanization rate can cause an increase in domestic energy consumption.There is a slight difference between the average total energy consumption levels of urban and rural residents,but their energy consumption structures differ a lot.These findings provide basic data support and reference for local governments to formulate energy-conservation and emission-reduction policies.

New Strategy and Kinetic Energy Regeneration for the Developmen of China’s Urban Agglomeration

The rapid development of modern urban agglomerations has reshaped the territory of China’s economic geography and reconstructed the spatial forms of Chinese cities and regions.Since the reform and opening-up,China’s urban agglomerations have experienced three stages,i.e.spontaneous cultivation,rapid growth,and the super leading role of planning.The gian development area composed of super urban agglomerations is becoming an emerging geographic unit that improves the urban development quality promotes regional integration processes and participates in global industria competition and innovative resource allocations in China.While encountering challenges such as insufficient innovation kinetic energy and implementation difficulties of cross-regional coordination mechanisms,it has also ushered in new opportunities brought about by the shift of the global urban network system focus,the accelerated formation of high-speed rail urban belts,the rise of innovative geographic unit communities,etc.As entering the new era,centering on the high-quality development requirements of urbanization and urban agglomerations,China should establish a new mechanism for more effective coordinated regional development,build an urban pattern of coordinated development of large,medium and small cities and towns with urban agglomerations as the main body,comprehensively enhance the competitiveness of urban agglomerations and regions,and take a steady and innovation-driven road to modernization.

Toward a sustainable future:Examining the interconnectedness among Foreign Direct Investment(FDI),urbanization,trade openness,economic growth,and energy usage in Australia

The energy demand in Australia is increasing with the industrialization and rapid economic growth.This study analyzed the relationships among the economic growth,Foreign Direct Investment(FDI),trade openness,urbanization,and energy usage in Australia based on the data from World Development Indicators(WDI)from 1972 to 2021.The results indicates that there is a cointegration among economic growth,FDI,trade openness,urbanization,and energy usage,which was traced through the autoregressivedistributed lag(ARDL).The Zivot-Andrews unit root test reveals that energy usage,economic growth,FDI,urbanization,and trade openness show significant structural breaks in 1993,1996,1982,2008,and 1994,respectively.The ARDL model shows that economic growth has a positive and significant effect on energy usage in the long-run(0.814)and short-run(0.809).Moreover,the results also show that FDI(0.028)and trade openness(0.043)have positive impacts on energy usage in the long-run.However,urbanization shows a negative and significant influence on energy usage in the long-run(–0.965).Then,the research demonstrates a unidirectional causation between energy usage and trade openness,with energy usage significantly causing trade openness.The current study endorses energy consumption policies and investment strategies for a paradigm shifting from a reliance on fossil fuels as the primary energy source to renewable energy sources.These findings have profound implications for sustainable energy usage.

Conflict between Population and Urbanization Factors： Impact of Urban Heat Island on Energy Consumption Balance

High density of buildings and population in urban areas increases urban temperature, generally known as the urban heat island. Raised temperature, especially in SUlIuner, alms city centers into unwelcome hot areas, with direct effects on electricity demand and energy consttrnption for cooling buildings and increases the production of carbon dioxide and other pollutants. Therefore, by considering that the energy consumption in the world has been faced with intense crisis, it becomes increasingly important to study the effects of urban heat island on energy constunption in order to improve people＇s environment and decrease energy use in cities. This paper, therefore, is focused on urbanization and population size factors to understand tile influence way of these factors on formation of UHI and energy consumption balance. To achieve this aim, this paper explores literally the conceptual framework of confliction between population and urban structure, which produce UHI intensity and affected energy consumption balance. It is then discussed how these two factors can be affected and give implication to the city, and then, focuses on whether actions should be taken for balancing adaptation and mitigation UHI effects. It will be concluded by making the recommendations for preventive action and provide quality of life.

Data Center as a Key Player of a District Electric Power and Heat Network System： A Comparison in Urban and Suburb Regions

A DC （data center） demands air-conditioning power as large as the 1/3-1/2 of total electricity consumption. Thus, energy saving of cooling power of DC yields considerable effect on both economic and environmental views. PV （Photovoltaic） and absorption refrigerator with CGS （cogeneration systems） or gas boiler are possible power saving options. The waste warm air from DC would be utilized for greenhouse heating when DC and greenhouse locate near in the suburbs. In this study, the authors develop an energy network model to assess the potential contribution of DC as a major electric power and chilled air consumer as well as the warm air supplier in a district to the energy efficiency improvement. The evaporation heat of LNG （liquefied natural gas） utilization is also considered as well as PV, CGS. This model is applied to the cases of the urban area in Tokyo which involves athletic center, shops and hospital and the suburbs including greenhouse and then compared.

The Research on Energy Saving Technology Management of Urban Rail Transit

This paper summarizes the encrgy consumption of rail transit and the current situation of energy saving. Then it puts forward a number of policy support measures on the technology management from several aspects, such as the raft line, traction power supply, energy-saving mode and so on The related research helps urban rail transit enterprises save energy consumption, reduce costs to improve their market competitiveness, as well as to promote the enterprises to fulfill social responsibility and carry out the sustainable development idea.