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In the face of the ever-increasing pressure on climate change, recent decades witnessed booming interests in the integrated energy systems (IES) consisting of intermittent renewable energy and dispatchable power sources, such as reformed gas-fed solid oxide fuel cells (SOFC). However, optimization of system design and operation is challenging due to the system complexity, inevitable couplings, and various constraints. To this end, this paper proposes a comprehensive model to describe integrated energy systems with combined cooling, heating, and power (CCHP). Optimal economic performance is formulated as the objective function. Constraints are derived based on the safety and operation requirements. The problem is solved by developing a two-stage stochastic programming framework to achieve the optimized results in terms of both design and operation. The second stage concerns the operation scheduling given the operation plan and stochastic characteristics, based on which the first stage concerns the design planning to realize the prescribed CCHP capacity. Considering the computation complexity of the second stage, the stochastic characteristics are represented by selected scenarios. And to present the mutual influence of energy demands and climate conditions, the time sequence correlation among energy demands and renewable energy availability is considered in the clustering-based scenario selection technique. To solve the proposed two-stage framework, the real-coded genetic algorithm and mixed integer linear programming method are applied in the first and second stages, respectively. A case study in San Francisco is carried out to verify the effectiveness of the proposed method, providing some intuitive guidance for future IES operation and system planning. [ABSTRACT FROM AUTHOR]

This paper presents the design, theoretical modelling and experimental validation of a quad-stable energy harvester for harnessing ultra-low frequency random motions using a nonlinear pendulum and piezoelectric transduction. The multi-stable pendulum is created by the magnetic forces between magnets on the pendulum and a tip magnet on a piezoelectric cantilever beam. Two attractive and one repulsive magnetic forces in combination with the gravitational force of the pendulum create multiple stable positions for the pendulum. The multi-stable dynamics allow the pendulum to effectively convert low-frequency random kinetic motions from the host, e.g. human motion or wind turbine tower oscillation into the pendulum oscillation, enabling effective plucking of the piezoelectric beam with enhanced output power. A theoretical model, including the magnetic interaction, piezoelectric conversion and pendulum dynamics, is established to describe the electromechanical dynamics of the whole harvester. A prototype is fabricated and tested on a linear shaker at ultra-low frequencies (1–3 Hz) to showcase the capability of the harvester and to validate the theoretical results. Around 8 μ W Root-Mean-Square output power was obtained at 2.5 Hz and 0.8 g of excitation. Using the experimentally validated theoretical model, a parametric study was carried out to examine the influence of different structural and operating parameters, such as pendulum mass and length, magnetic coupling strength, excitation frequency and amplitude, on the output power and operating frequency range of the energy harvester. The operation frequency range and output power can be effectively adjusted by changing the above-mentioned parameters. The self-powered sensing capability is then illustrated by integrating the harvester with an off-the-shelf power management circuit and a 22 μ F storage capacitor. The capacitor was charged from 2.8 V to 4 V in 90 s, showing its capability of implementing battery-free wireless sensing for different Internet of Things (IoT) applications. • A multi-stable pendulum-based harvester is developed for low-frequency random motion. • A distributed-parameter theoretical model is built and experimentally validated. • Cross-well oscillation, bandwidth and output can be adjusted by different parameters. • The piezoelectric energy harvester shows a wide bandwidth between 1 Hz and 3 Hz. • A self-powered sensing solution is established using the developed energy harvester. [ABSTRACT FROM AUTHOR]

Accurately understanding the real situation of China’s carbon emissions at the provincial level is not only crucial for realizing carbon mitigation in China, but also of great importance for tackling climate change on a global scale. This paper uses detailed energy consumption data subdivided within each fuel type and sector-specific emission factors, to calculate both direct and indirect energy-related CO 2 emissions for China’s provinces, and offers provincially-targeted policy proposals on emission reductions. The results uncover large divergences in calculation of provincial CO 2 emissions between production-based and consumption-based accounting approaches. Considering the large amount of interprovincial CO 2 emission transfers embodied in secondary energy deployment, the consumption-based accounting performs better in reflecting the actual features and responsibilities of carbon emissions in the provinces of China. From the consumption perspective, Shandong, Hebei, Jiangsu, Inner Mongolia, Guangdong, Henan, Liaoning and Shanxi contributed to the majority of China’s carbon emission growth during the period of 1996–2013, while Xinjiang, Sichuan, Anhui, Tianjin and Hunan were playing an increasingly important role. These two groups of provinces should be regarded as the key regions for national emissions abatement. Meanwhile, the energy industry was the top sectoral contributor to CO 2 emissions growth in most provinces, while service and household sectors made increasingly significant impacts on driving up provincial emissions. Together with ongoing efforts in the energy sector, the mitigation of CO 2 emissions in service and household sectors deserves much more attention, especially in the transportation and urban household sectors. Furthermore, the temporal trends of carbon emissions in various provinces, as well as their factor and sectoral driving forces, varied greatly with each other. Therefore, each of the provinces should formulate emission reduction policies according to their own situation, and target the key driving factors and sectors of carbon emissions at the current stage or in the near future. [ABSTRACT FROM AUTHOR]

Many different approaches are needed to achieve reductions in GHG emissions from the transportation sector. Carbon emissions trading schemes (ETSs) are widely used in industry and are effective in reducing the overall social cost of emissions abatement. This article reports the development of a downstream ETS for the transportation sector and its application in Shenzhen, China. The ETS was devised as a mandatory cap-and-trade scheme and, as a first step, was applied to public transportation. An integrated cap was set on the total emissions from buses and taxis: an absolute cap for existing vehicles and a relative increment for new entrants. Allowances were allocated by grandfathering or benchmarking and a ‘reverse mechanism’ was established to encourage the transformation of urban transportation to a low-carbon system. Online fuel consumption monitoring was used to quantify the emissions from vehicles, and the operators were required to surrender enough allowances or credits to account for their verified annual emissions. The mechanisms for allowance trading and carbon offsets provided sufficient flexibility to make emissions abatement and the use of new-energy vehicles and environmentally friendly travel within Shenzhen's urban transportation system economically attractive. Policy relevance The transportation sector is becoming a major contributor to the growth in China's GHG emissions. Achieving large reductions in GHG emissions from the transportation sector is a great challenge and requires both technology and policy innovation. The tradable carbon permit is a popular concept in mitigating climate change, but the introduction of a cap-and-trade ETS into the transportation sector is a relatively innovative concept. Shenzhen has launched the first cap-and-trade ETS in a developing country and is currently exploring ways to mitigate carbon emissions by a downstream cap-and-trade ETS for the transportation sector. This article considers the main institutional arrangements and regulatory framework of Shenzhen's transportation carbon ETS. It not only refreshes the theoretical analysis and practical application of downstream cap-and-trade carbon emissions trading in urban transportation, but also provides developing countries with a cost-effective instrument to mitigate their rapid growth in traffic carbon emissions during urbanization. [ABSTRACT FROM AUTHOR]

Urban areas are the key drivers of energy usage and the associated carbon emissions. Due to the rapid economic development and urbanization process, China has faced increasing pressure on energy supply and carbon emission issues. It is urgent for China to change from the current coal-based high carbon intensity power supply structure. In this context, China has planned to utilize an undeveloped area in Shenzhen to become a low-carbon development demonstration project. The purpose of this paper is to propose the best combination of technology for electricity generation, involving a mix of renewable energy resources, to satisfy electrical needs and, at the same time, minimize carbon emissions from power generation in the low carbon demonstration area. The optimal renewable energy system configuration was determined based on the Hybrid Optimization Model for Electric Renewable model. The simulation results show that costs of energy for the three scenarios considered are $0.187/kW h, $0.128/kW h, and $0.150/kW h, respectively; annual carbon emissions for the three scenarios are 96 702 tons, 89 836 tons, and 78 065 tons, respectively. Given the economic advantage, scenario 2 is a suitable choice for the first phase of the international low carbon city (ILCC). With reinforced carbon emissions controls and a rising carbon allowance price, scenario 3 can be adopted in the second and third phase of the ILCC construction. [ABSTRACT FROM AUTHOR]

[Display omitted] • β-CD@CdS NRs were fabricated as building modules for photoelectrochemical miR-141 assay. • CHA-mediated the assembly of Cu 2 O NCs served as efficient dual-quenching tags. • Desirable analytical properties stemmed from the combination of CHA recycling and Cu 2 O NCs. • The biosensor achieved great prospect in analysis of human serum samples. MicroRNAs (miR) as newly identified biomarkers are closely associated with various cancers, and sensitive monitoring of abnormal miR is great importance in cancer diagnosis. In this work, a novel photoelectrochemical biosensor was developed to sensitively detect miR-141 by the competitive dual-quenching of catalytic hairpin assembly (CHA)-dependent Cu 2 O nanocubes (NCs) toward β-CD-functionalized CdS nanorods (β-CD@CdS NRs). The biosensing platform was constructed by the stepwise assembly of β-CD@CdS NRs and adamantane-labeled hairpin DNA probe 1 on ITO electrode. In the presence of miR-141, CHA recycling was triggered to immobilize the capture DNA-labeled Cu 2 O NCs with the aid of hairpin DNA probe 2. The assembly of Cu 2 O NCs could largely reduce the photocurrent response of CdS NRs based on the competitive consumption of light energy and electron donor. The designed biosensor showed a wide linear range (1.0 pM–100 nM) and a detection limit of 0.47 pM, as well as excellent selectivity and satisfactory stability. Based on the above outcomes, the proposed biosensing device was also applied to miR-141 analysis in human serum with the recoveries ranging from 95.9 % to 104.7 %, achieving a great prospect in clinical application. [ABSTRACT FROM AUTHOR]

Highlights: [•] The air-conditioning system of a datacenter in Beijing is tested. [•] COPsys is approaching to 9 for free cooling while about 3 for mechanical cooling. [•] Suggestions are proposed to improve the temperature distribution of cabinet. [•] An innovative LTD (large temperature difference) distribution system is proposed. [•] It is of significant improvement in energy efficiency for this new process. [ABSTRACT FROM AUTHOR]

Abstract: Reducing the energy consumption of air-conditioning systems is becoming increasingly important. This paper focuses on the air-conditioning system in Terminal 3 in Xi’an Xianyang International Airport, the first airport terminal to adopt radiant cooling in China. In the large spaces of this airport terminal, a temperature and humidity independent control (THIC) system has been adopted instead of a conventional nozzle air supply method, which significantly reduces the energy consumption of the air supply. The radiant floor is the main mechanism for indoor temperature control, while a liquid desiccant outdoor air processor combined with displacement ventilation is responsible for humidity control. Ice storage is adopted to reduce operating costs, and the supplied chilled water temperature can be as low as 3°C. This paper examines the performance of the THIC system in detail. The indoor environment is determined through measurements to be comfortable, and the on-site performances of key components in both the airport terminal and the cooling plant are investigated. The outdoor air processor supplies air of appropriate temperature and humidity ratio; two kinds of radiant floors are used for temperature control, both with measured cooling capacities of about 30–40W/m2; and the energy efficiency ratio (EER) of the cooling plant is 2.62. [Copyright &y& Elsevier]