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China's Hot Summer and Cold Winter zone, with a 550 million population, accounts for 45% of China's building energy consumption; as such, building retrofits could offer substantial energy savings. This paper presents results from a dynamic thermal modeling study of a typical urban multistory residential building under three types of air conditioning (A/C) operating schedules. Seven energy-saving retrofit measures (external wall insulation, roof insulation, double-glazing, air infiltration control, window shading, communal staircase design, and energy-efficient A/C) were evaluated, and the retrofit strategy with the highest annual energy savings and lowest thermal discomfort was identified. This retrofit strategy was subsequently evaluated for other flats (apartments) with different orientations and positions in the typical building. The annual space-conditioning energy could be reduced by 59%–68%, depending on the flat location, orientation and A/C operating schedule. The findings were then scaled up to estimate the potential energy savings in the city of Chongqing. More than 320 multistory residential buildings were represented by 12 archetypes. Space-conditioning energy consumption was reduced by up to 58% (18.8 TWh). This work provides evidence of the potential energy savings of city-scale retrofit that could aid China in reducing building energy consumption and achieving net-zero carbon emissions by 2050. It was possible to explore a wide range of refurbishment options for China's highly energy-consuming Hot Summer and Cold Winter zone with hot, humid summers and mild, chilly winters using dynamic thermal models. The simulation models developed in this paper revealed that double-glazing with air infiltration control is the most effective retrofit measure for middle-floor flats, but for top-floor flats, roof insulation is the most effective; south-facing flats consume more high energy consumption than north-facing flats. Furthermore, high-rise buildings consume less energy than low-rise buildings per square meter, and one-bedroom flats consume more energy than three-bedroom flats per square meter. This study also demonstrated the procedure to develop thermal comfort evaluation methods, A/C operating schedules, and construction parameters from literature in this climate zone when there were no standards or databases available. Findings offer a tangible, clear retrofit strategy that considers different A/C operating schedules, flat locations, and building archetypes. It can assist decision-making by practitioners and homeowners aiming to upgrade the building stock of this climate zone which covers 3.4 billion m2 with a 550 million population to reduce energy consumption and improve occupant comfort. [ABSTRACT FROM AUTHOR]

Reducing energy consumption is becoming a more and more essential consideration for low carbon manufacturing. In this paper, an operation scheduling approach is proposed for a multi-hydraulic press system to explore the potential on energy saving at system level. In the multi-hydraulic press system, a drive is composed of several motor-pumps and supplies energy to each press according to a given schedule. The scheduling formulation is developed based on power models of the forming process on an individual press. At single press level, models of energy conversion units, including asynchronous motors, piston pumps, hydraulic cylinders, valves and pipes are built by identifying their energy dissipation characteristics. Based on the established model of a single press and scheduling formulation, the energy consumption model and makespan at multi-press level are obtained. In order to balance makespan and energy consumption, the duration of each operation is adjusted by optimizing the configuration of the drive and the schedule of operations. To demonstrate the applicability of the proposed approach, a case study on a four presses system is presented. The results show that this approach is effective in identifying schedules to reduce makespan and total energy consumption during forming processes. [ABSTRACT FROM AUTHOR]

Residential buildings are mostly sensitive to climatic conditions; building envelopes work as the interface between indoor and outdoor environments, preventing heat gain in the summer and heat loss in the winter. Proper use of energy storage technologies may reduce greatly the energy needs in residential dwellings while delivering better indoor environment quality. This paper provides a brief review of several energy storage technologies, both active and passive, for residential building applications. Particular attention is paid to the usage of phase change materials (PCMs), which have been studied for a few decades with a recent growing interest. Modeling methods of PCM-embedded wall systems are reviewed comparatively and a new simulation program is developed that can simulate the thermal and energy performance of PCM-embedded walls and buildings in a more stable and fast manner. The paper also presents a case study that integrates PCM with the traditional kang heating system for the residential dwellings in northeastern rural China. Both technical and economic performances of the solution are explored. [ABSTRACT FROM AUTHOR]

Abstract: The continuing growth of China''s electricity sector will affect global environmental and economic sustainability due to its impacts on greenhouse gas emissions and global resource depletion. In 2005, the generation of electricity in China resulted in the emissions of 2290 million metric tonnes of carbon dioxide (approximately 53% of the nation''s total) and required 779 million metric tonnes of coal (approximately 50% of China''s total coal consumption). These figures are expected to increase with China''s economic growth. In order to gauge the range in which fuel consumption and CO2 emissions could grow a scenario-based conceptual model has been developed by the authors (published in (vol.) of this journal). The application and analysis of this shows that under a business as usual (BAU) scenario, electricity generation could contribute upwards of 56% of China''s energy related greenhouse gas emissions by 2020. Meanwhile, consumption of coal will also increase, growing to nearly 60% of total national demand by 2020. However, variations in a number of key drivers could produce significant deviation from the BAU scenario. With accelerated economic output, even with greater technological advances and greater potential to bring natural gas on stream, carbon dioxide emissions would rise 10% above the BAU. Alternatively, in a scenario where China''s economy grows at a tempered pace, less investment would be available for advanced technologies, developing natural gas infrastructure, or nuclear energy. In this scenario, reduced economic growth and electricity demand would thereby be countered by reduced efficiency and a higher contribution of coal. [Copyright &y& Elsevier]

Abstract: China has attracted worldwide attention due to the global economic and environmental effects of its rapid economic growth over the last 20 years, with particular attention given to the country''s accelerating energy consumption and resulting greenhouse gas emissions. China''s electricity sector is particularly important for both of these issues as it accounts for nearly half of its greenhouse gas emissions and even greater proportions of the country''s demands for primary fuel resources. In order to better understand how these issues may progress in an economy changing as fast as China''s, this paper develops a framework that can be used to help model the electricity sector''s future development. The framework builds upon key technological and socio-economic drivers, including those affecting electricity demand (e.g., economic growth, structure, energy efficiency, urbanization, and change in per capita income) and electricity supply (e.g., deregulation, initiatives to promote natural gas, nuclear and renewable energy, air pollution regulations, price developments for coal and natural gas, and changes in generation technology). The framework serves as a foundation for a scenario exercise on the greenhouse gas and fuel consumption impacts of different developmental paths for China''s electricity sector. These scenarios and their implications for emissions and fuel consumption are presented in a subsequent article. [Copyright &y& Elsevier]