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Abstract The industrial exhaust flue gas contains tremendous waste heat that cannot be efficiently recovered by conventional condensing heat exchanger. This paper proposes a novel full-open absorption heat pump for the total heat recovery of flue gas. The recovered heat is used for district heating. By applying direct-contact heat and mass transfer without solid transfer interfaces, the novel system can save considerable metallic tube or plate materials and therefore the initial investment can be reduced substantially. A prototype full-open absorption heat pump is developed and tested, achieving the COP (coefficient of performance) of 1.621 and the exit flue gas dew point of 36.2 °C at most. A detailed theoretical model in Eulerian–Lagrangian formulation is established, involving in conjugate heat and mass transfer and particle dynamics. The numerical simulation agrees well with the experiment results. On the basis of the validated model, three critical parameters, including excess air coefficient of the burner, moisture content of the objective flue gas and return water temperature of the district heating network, are selected to study their effects on system performances. As a controlled variable, especially, the excess air coefficient plays an important role by influencing the regeneration of the liquid absorbent in the generator. The full-open absorption heat pump outperforms the condensing heat exchanger by 19.7–178.1% in heat recovery capacity as the return water temperature increases from 40 to 55 °C.

The DC distribution system is an important development direction of the distribution system, which can improve the reliability and the quality of the power supply, and support the new energy, the energy storage, the electric vehicles, and the flexible access of AC and DC loads to grid. To realize the demonstration application of the DC distribution technology, China’s first demonstration project of the medium voltage DC distribution network will be built in Zhuhai, Guangdong Province to support the construction of the city energy internet. First, this paper analyzes the demand of the DC distribution network project, and puts forward the construction content and construction target. Then, it designs and analyzes the electrical connection mode, system operation mode, and startup and shutdown mode of the DC distribution network, and proposes the overall project construction plan. Finally, it conducts the specific project design and analysis, which mainly include the selection of equipment such as inverters, DC transformers and DC circuit breakers, the design and analysis of the DC control and protection system, the design and analysis of the over-voltage protection and the configuration scheme of the lightning arrester, and analysis of the system transient characteristics. The design and analysis of the engineering program is a combination of China’s distribution network engineering practice and technical characteristics, which lays a solid foundation for the advancement of the DC power distribution technology in China, and has reference value and demonstration effect for the design and construction of other projects.

Abstract The automotive operating protocols is a comprehensive expression of a country or a region’s road, climatic environment and driving habits. It is the foundation of energy consumption, test method and limit method for automobile products. It has direct impact on R & D, production and government access management of enterprises. For fuel cells vehicles, the lifetime is one of the main factors restricting their commercialization. Furthermore, the lifetime evaluation methods and its standard specifications of vehicular proton exchange membrane fuel cell are the critical factors to its technological development, but there is no authoritative recognized life evaluation method and test protocols so far. A logical fuel cell durability test protocol is the fundamental for developing the fuel cell life evaluation methods. A review on the state-of-art in the world for fuel cell accelerated test protocols was given, the research circumstances of different universities and research institutions in China, America, the European Union, Japan and so on are analyzed and summarized in detail. Then the essential characteristics and applicable environments of a comprehensive and effective durability test protocol are summarized based on the analysis and demonstration of the existing durability test protocols in literature. The work in this paper focuses on the research of durability test protocols of the fuel cell stack for the first time. The final conclusion will provide theoretical basis for establishing fuel cell durability test specifications and proposing life evaluation methods, and make a contribution to the long life research of vehicular fuel cells.

Abstract The civil nuclear energy deployment in China is important for future “Nuclear Renaissance” of China and worldwide. Compared to the other nations that developed their nuclear power energy system in last century, China can take advantage of the research and mistakes made by those states with regards to the back-end of the nuclear fuel cycle (NFC). The spent fuel accumulated by decades of operations of civil nuclear power is today a big burden for the nuclear industry. China must carefully plan the NFC for a sustainable development of the nuclear energy with special consideration to closing the fuel cycle. The present paper addresses the NFC option and implication of a LWR reactors scenario development and of a fast reactor park developed after 2035 and 2050, and covers the historical development of nuclear energy in China (i.e. from the first criticality of the first reactor) to the year 2100. The paper studies the partition and transmutation strategy with the use of accelerator driven system (ADS) to burn the MA to understand the ADS impact on the NFC and to estimate the number and the necessary deploying schedule of the ADS reactors to limit the minor actinides stock build up. The code INFCIS developed by the International Atomic Energy Agency (IAEA) is used in the present study.

Abstract Motor vehicle emissions contribute significantly to air pollution in Beijing. Therefore, a number of measures have been taken to control emissions from motor vehicles, including the elimination of high-polluting old vehicles and driving restrictions. We compared the pollution reduction effects and implementation costs of these two policies. The results showed that an average annual investment of about 1.7 billion RMB was invested in a policy of eliminating old vehicles in Beijing, resulting in annual emissions reductions of about 22,600 tons of CO, 1330.2 tons of NOx, 2197 tons of HC, 78.6 tons of PM2.5, and 81.3 tons of PM10. Meanwhile, a driving restrictions policy resulted in an annual loss by consumers of more than 17.84 billion RMB and annual emissions reductions of just 12,000 tons of CO, 845 tons of NOx, 1356 tons of hydrocarbons HC, 53 tons of PM2.5, and 57 tons of PM10. A policy of eliminating old cars is more cost-effective than a driving restrictions policy, policy formulation should take into account the cost-effectiveness of policies.

Abstract Traditional life cycle assessment (LCA) methods are used to conduct building environmental impact assessment (EIA) with little consideration of influential factors that vary in time and of variation in occupancy behaviors. Because the life cycle of a building is quite long, such details have significant influence on the accuracy of evaluation results. To fill in this gap and extend the LCA system, this paper developed a dynamic assessment framework based on LCA principles after reviewing the research progress of DLCA (dynamic LCA). The new framework identified four dynamic building properties (i.e., technological progress, variation in occupancy behavior, dynamic characteristic factors, and dynamic weighting factors) and considered them in corresponding assessment steps to realize real-time EIA. In addition, residential occupancy profiles were described at personal level, family level, and social level; and three potential quantification methods were introduced to explore the relationship between occupancy profiles and household energy consumption. The DLCA framework expands the connotation of the LCA system from a dynamic perspective, making it possible to present time-varying EIs of buildings over their long life cycle and guide occupancy behavior in time. This framework has the potential to be base for developing a useful tool for conducting forecast evaluation and promoting sustainability.

Abstract Effective low carbon transport policy-making needs to first understand what are the factors influencing residents’ modal choice and how it can be intervened. This study uses a discrete choice model to analyse the factors influencing residents’ mode choice in Beijing. A questionnaire survey was conducted in 2015, with sample data containing 865 respondents and 1704 trips collected. The results suggest that residents’ mode choice is closely related to their characteristics. Moreover, our study has linked residents’ mode choice with travel carbon emissions and estimated the emissions reduction potential of those policy measures aiming to improve public transport. For commuting and education trips, public transport improvements can reduce carbon emissions by 12.3~16.6% on average, but for other trip purposes, the reduction is only 2.9~6.8%. As commuting and education trips account for the largest proportion of urban residents’ daily travels, it suggests that policy should primarily focus on the improvement of public transport and its particular support for major commuting routes.

Abstract China as a whole is undergoing rapid industrial structure change, but this process is proceeding in a particularly unequal manner across regions. Understanding these changes and their associated impacts on CO2 emissions in these regions is a vital step toward appropriately targeted policy making. In this paper, we conduct both regional analysis throughout the nation and case studies focused on nine typical regions in order to identify regional patterns of industrial structure change and CO2 emissions. Results indicate that structural change in primary, secondary, and tertiary sectors was highly correlated, but structural change by industrial sector did not correspond well, with the stage of economic development. The disparity in regional industrial structure impacts regional CO2 emissions substantially. First, industrial structure changes involving a shift from agriculture, mining, and light manufacturing to resource-related heavy manufacturing in many regions led to a rapid increase in CO2 emissions at the national level. Second, production structure change, especially in construction and services sectors, is an important source of CO2 emission growth in regions. Some developed regions with vastly improved input efficiency in resource-related heavy manufacturing demonstrate the immense potential for reducing CO2 emissions in regions lagging in input efficiency. Third, regions with a more developed industrial structure avoided local CO2 emissions by importing carbon-intensive products while exporting less carbon-intensive but higher-value-added products in the machinery and equipment and service sectors. Several policy implications are also discussed based on the main findings of this study.

Abstract Urban built environment regulations can effectively mitigate traffic CO2 emissions. Thus, it is critical to quantify the elasticities of altering built environment configurations. To address this issue, we have built nationwide spatial autoregressive models to differentiate between localized and spillover effects across 325 Chinese cities in the years of 2005 and 2015. Our results indicate that a 1% increase in built-up areas’ size, compactness, and isolation is associated with increases of 0.35%, −0.14%, and 0.13%, respectively, in adjacent traffic CO2 emissions. The underlying reason is that the spatial configurations of built environment do not only systemically affect the probability, frequency, speed, and distance of intracity motorised travels, but also have impacts on the intercity transboundary mobility of motor vehicles. In addition, the built-up areas’ compactness effect has an antagonistic relation with the per capita GDP effect. Thus, our findings provide evidence that the built environment configuration-related measures can benefit traffic CO2 emission reductions in adjacent cities. It is therefore necessary for policymakers to make a traffic CO2 mitigation strategy at the city agglomeration level.