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Energy efficiency of small buildings with smart cooling system in the summer

Yazdan DANESHVAR, Majid SABZEHPARVAR, Seyed Amir Hossein HASHEMI

《能源前沿（英文）》 2022年第16卷第4期页码 651-660 doi: 10.1007/s11708-020-0699-7

摘要： In this paper, a novel cooling control strategy as part of the smart energy system that can balance thermal comfort against building energy consumption by using the sensing and machine programming technology was investigated. For this goal, a general form of a building was coupled by the smart cooling system (SCS) and the consumption of energy with thermal comfort cooling of persons simulated by using the EnergyPlus software and compared with similar buildings without SCS. At the beginning of the research, using the data from a survey in a randomly selected group of hundreds and by analyzing and verifying the results of the specific relationship between the different groups of people in the statistical society, the body mass index (BMI) and their thermal comfort temperature were obtained, and the sample building was modeled using the EnergyPlus software. The result show that if an intelligent ventilation system that can calculate the thermal comfort temperature was used in accordance with the BMI of persons, it can save up to 35% of the cooling load of the building yearly.

关键词： smart home heating and cooling systems saving energy optimal consumption of energy

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Basic model study on efficiency evaluation in collaborative design work process

XIE Qiu, YANG Yu, LI Xiaoli, ZHAO Ningyu

《机械工程前沿（英文）》 2007年第2卷第3期页码 344-349 doi: 10.1007/s11465-007-0060-4

摘要： During the efficiency evaluation process of collaborative design work, because of the lack of efficiency evaluation models, a basic analytical model for collaborative design work efficiency evaluation is proposed in this paper. First, the characteristics of the networked collaborative design system work process were studied; then, in accordance with those characteristics, a basic analytical model is created. This model, which is built for centralized collaborative design work, includes an analytical frame, a process view model, a function view model and an information view model. Finally, the application process and steps of this basic analytical model are elaborated when used for efficiency evaluation through an experiment.

关键词： function system work evaluation process efficiency evaluation design work

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ROLE OF NITROGEN SENSING AND ITS INTEGRATIVE SIGNALING PATHWAYS IN SHAPING ROOT SYSTEM ARCHITECTURE

《农业科学与工程前沿（英文）》 2022年第9卷第3期页码 316-332 doi: 10.15302/J-FASE-2022441

摘要：

● The Green Revolution broadened the trade-off between yield and nitrogen-use efficiency.

关键词： Nitrogen root system architecture phytohormone crosstalk nitrogen-use efficiency breeding strategy

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Efficiency measurement for mixed two-stage nonhomogeneous network processes with shared extra intermediate

Qingxian AN, Xuyang LIU, Shijie DING

《工程管理前沿（英文）》 2020年第7卷第2期页码 259-274 doi: 10.1007/s42524-019-0080-x

摘要： Unreasonable allocation of shared resources reduces the system efficiency and is a considerable operational risk. Sub-processes with insufficient portion of shared resources could not help accomplish complicated tasks, and overstaffing and idle resources will occur in the sub-processes assigned with redundant shared resources. This unfair portion distribution may cause internal contradictions among sub-processes and even lead to the collapsing of the entire system. This study proposes a data-driven, mixed two-stage network data envelopment analysis model. This method aims to reasonably define the allocation portion of shared extra intermediate resources among several nonhomogeneous subsystems and measure the overall system performance. A data set of 58 international hotels is used to test the features of the proposed model.

关键词： shared resource allocation mixed two-stage system data envelopment analysis efficiency

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Characteristics and application of road absorbing solar energy

Zhihua ZHOU, Shan HU, Xiaoyan ZHANG, Jian ZUO

《能源前沿（英文）》 2013年第7卷第4期页码 525-534 doi: 10.1007/s11708-013-0278-2

摘要： If the heat of road surface can be stored in summer, the road surface temperature will be decreased to prevent permanent deformation of pavement. Besides, if the heat stored is released, it can supply heat for buildings or raise the road surface temperature for snow melting in winter. A road-solar energy system was built in this study, and the heat transfer mechanism and effect of the system were analyzed according to the monitored solar radiant heat, the solar energy absorbed by road and the heat stored by soil. The results showed that the road surface temperature was mainly affected by solar radiation, but the effect is hysteretic in nature. The temperature of the solar road surface was 3°C–6°C lower than that of the ordinary road surface. The temperature of the solar road along the vertical direction was 2°C–5°C lower than that of the ordinary road. The temperature difference increased as the distance to the heat transfer tubes decreased. The average solar collector efficiency of the system was 14.4%, and the average solar absorptivity of road surface was 36%.

关键词： solar energy road-solar energy system road surface temperature solar absorptivity of road surface solar collector efficiency of system

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Simulation and experiments on a solid sorption combined cooling and power system driven by the exhaust

Peng GAO, Liwei WANG, Ruzhu WANG, Yang YU

《能源前沿（英文）》 2017年第11卷第4期页码 516-526 doi: 10.1007/s11708-017-0511-5

摘要： A solid sorption combined cooling and power system driven by exhaust waste heat is proposed, which consists of a MnCl sorption bed, a CaCl sorption bed, an evaporator, a condenser, an expansion valve, and a scroll expander, and ammonia is chosen as the working fluid. First, the theoretical model of the system is established, and the partitioning calculation method is proposed for sorption beds. Next, the experimental system is established, and experimental results show that the refrigerating capacity at the refrigerating temperature of –10°C and the resorption time of 30 min is 1.95 kW, and the shaft power is 109.2 W. The system can provide approximately 60% of the power for the evaporator fan and the condenser fan. Finally, the performance of the system is compared with that of the solid sorption refrigeration system. The refrigerating capacity of two systems is almost the same at the same operational condition. Therefore, the power generation process does not influence the refrigeration process. The exergy efficiency of the two systems is 0.076 and 0.047, respectively. The feasibility of the system is determined, which proves that this system is especially suitable for the exhaust waste heat recovery.

关键词： solid sorption exhaust waste heat combined cooling and power system exergy efficiency

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A NEW APPROACH TO HOLISTIC NITROGEN MANAGEMENT IN CHINA

《农业科学与工程前沿（英文）》 2022年第9卷第3期页码 490-510 doi: 10.15302/J-FASE-2022453

摘要：

● Progress on nitrogen management in agriculture is overviewed in China.

关键词： 4R technology food chain N management N use efficiency soil-crop system sustainable management

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The effect of different agricultural management practices on irrigation efficiency, water use efficiency

La ZHUO, Arjen Y. HOEKSTRA

《农业科学与工程前沿（英文）》 2017年第4卷第2期页码 185-194 doi: 10.15302/J-FASE-2017149

摘要： This paper explores the effect of varying agricultural management practices on different water efficiency indicators: irrigation efficiency (IE), crop water use efficiency (WUE), and green and blue water footprint (WF). We take winter wheat in an experimental field in Northern China as a case study and consider a dry, average and wet year. We conducted 24 modeling experiments with the AquaCrop model, for all possible combinations of four irrigation techniques, two irrigation strategies and three mulching methods. Results show that deficit irrigation most effectively improved blue water use, by increasing IE (by 5%) and reducing blue WF (by 38%), however with an average 9% yield reduction. Organic or synthetic mulching practices improved WUE (by 4% and 10%, respectively) and reduced blue WF (by 8% and 17%, respectively), with the same yield level. Drip and subsurface drip irrigation improved IE and WUE, but drip irrigation had a relatively large blue WF. Improvements in one water efficiency indicator may cause a decline in another. In particular, WUE can be improved by more irrigation at the cost of the blue WF. Furthermore, increasing IE, for instance by installing drip irrigation, does not necessarily reduce the blue WF.

关键词： field management irrigation efficiency water footprint water productivity water use efficiency

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Experimental investigation and feasibility analysis of a thermophotovoltaic cogeneration system in high-temperature

Jianxiang WANG, Hong YE, Xi WU, Hujun WANG, Xiaojie XU

《能源前沿（英文）》 2013年第7卷第2期页码 146-154 doi: 10.1007/s11708-013-0253-y

摘要： The experimental - characteristics of a Si cell module in a thermophotovoltaic (TPV) system were investigated using SiC or Yb O radiator. The results demonstrate that the short-circuit current increases while the open-circuit voltage, along with the fill factor, decreases with the cell temperature when the radiator temperature increases from 1273 to 1573 K, leading to a suppressed increase of the output power of the system. The maximum output power density of the cell module is 0.05 W/cm when the temperature of the SiC radiator is 1573 K, while the electrical efficiency of the system is only 0.22%. The efficiency is 1.3% with a Yb O radiator at the same temperature, however, the maximum output power density drops to 0.03 W/cm . The values of the open-circuit voltage and the maximum output power obtained from the theoretical model conform to the experimental ones. But the theoretical short-circuit current is higher because of the existence of the contact resistance inside the cell module. In addition, the performance and cost of TPV cogeneration systems with the SiC or Yb O radiator using industrial high-temperature waste heat were analyzed. The system electrical efficiency could reach 3.1% with a Yb O radiator at 1573 K. The system cost and investment recovery period are 6732 EUR/kWel and 14 years, respectively.

关键词： thermophotovoltaic (TPV) industrial waste heat ytterbium oxide system efficiency

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Evaluating R&D efficiency of China’s listed lithium battery enterprises

《工程管理前沿（英文）》页码 473-485 doi: 10.1007/s42524-022-0213-5

摘要： Promoting the growth of the lithium battery sector has been a critical aspect of China’s energy policy in terms of achieving carbon neutrality. However, despite significant support on research and development (R&D) investments that have resulted in increasing size, the sector seems to be falling behind in technological areas. To guide future policies and understand proper ways of promoting R&D efficiency, we looked into the lithium battery industry of China. Specifically, data envelopment analysis (DEA) was used as the primary approach based on evidence from 22 listed lithium battery enterprises. The performance of the five leading players was compared with that of the industry as a whole. Results revealed little indication of a meaningful improvement in R&D efficiency throughout our sample from 2010 to 2019. However, during this period, a significant increase in R&D expenditure was witnessed. This finding was supported, as the results showed that the average technical efficiency of the 22 enterprises was 0.442, whereas the average pure technical efficiency was at 0.503, thus suggesting that they were suffering from decreasing returns to scale (DRS). In contrast, the performance of the five leading players seemed superior because their average efficiency scores were higher than the industry’s average. Moreover, they were experiencing increasing scale efficiency (IRS). We draw on these findings to suggest to policymakers that supporting technologically intensive sectors should be more than simply increasing investment scale; rather, it should also encompass assisting businesses in developing efficient managerial processes for R&D.

关键词： Data Envelopment Analysis R&D investment efficiency China’s listed lithium battery enterprises technical efficiency pure technical efficiency scale efficiency

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Improving the efficiency and effectiveness of global phosphorus use: focus on root and rhizosphere levelsin the agronomic system

null

《农业科学与工程前沿（英文）》 2019年第6卷第4期页码 357-365 doi: 10.15302/J-FASE-2019275

摘要：

Phosphorus (P) is essential for life and for efficient crop production, but global P use with limited recycling is inefficient in several sectors, including agronomy. Unfortunately, plant physiologists, agronomists, farmers and end users employ different measures for P use efficiency (PUE), which often masks their values at different scales. The term P use effectiveness, which also considers energetic and sustainability measures in addition to P balances, is also a valuable concept. Major physiological and genetic factors for plant P uptake and utilization have been identified, but there has been limited success in genetically improving PUE of modern crop cultivars. In maize, studies on root architectural and morphological traits appear promising. Rhizosphere processes assist in mobilizing and capturing sparingly soluble phosphate from rock phosphate. Combinations of phosphate-solubilizing microorganisms with ammonium-based nitrogen fertilizer, as well as strategies of fertilizer placement near the roots of target crops, can moderately enhance PUE. The desired concentration of P in the products differs, depending on the final use of the crop products as feed, food or for energy conversion, which should be considered during crop production.

关键词： acquisition efficiency plant growth promoting rhizobacteria phosphate use efficiency utilization efficiency

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Optimization and performance prediction of a new near-zero emission coal utilization system with combined

GUAN Jian, WANG Qinhui, LI Xiaomin, LUO Zhongyang, CEN Kefa

《能源前沿（英文）》 2007年第1卷第1期页码 113-119 doi: 10.1007/s11708-007-0013-y

摘要： In accordance with the new near-zero emission coal utilization system with combined gasification and combustion, which is based on the CO acceptor gasification process, the product gas composition of the gasifier and the combustor was calculated by means of thermodynamic equilibrium calculation software FactSage 5.2. Based on these calculations, the whole system efficiency calculation method that complies with the mass and energy conservation principle was established. To enhance the system efficiency, the system pressure and the gasifier carbon conversion ratio were optimized. The results indicate that the system efficiency increases with increasing pressure and gasifier carbon conversion ratio. After taking into consideration the influence of the pressure and carbon conversion ratio on the performance of the system, the gasifier and the combustor were synthetically studied. The optimum system pressure and carbon conversion ratio were obtained as 2.5 MPa and 0.7, respectively. The system efficiency could reach around 62.1% when operated in these two optimum parameters. If the advanced ion transport membrane (ITM) air separation technology is used, there would be an increase of another 1.3%.

关键词： influence efficiency calculation optimum software FactSage transport

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Optimization of power and efficiency for an irreversible Diesel heat engine

Shiyan ZHENG, Guoxing LIN

《能源前沿（英文）》 2010年第4卷第4期页码 560-565 doi: 10.1007/s11708-010-0018-9

摘要： A cyclic model of an irreversible Diesel heat engine is presented, in which the heat loss between the working fluid and the ambient during combustion, the irreversibility inside the cyclic working fluid resulting from friction, eddies flow, and other irreversible effects are taken into account. By using the thermodynamic analysis and optimal control theory methods, the analytical expressions of power output and efficiency of the Diesel heat engine are derived. Variations of the main performance parameters with the pressure ratio of the cycle are analyzed and calculated. The optimum operating region of the heat engine is determined. Moreover, the optimum criterion of some important parameters, such as the power output, efficiency, pressure ratio, and temperatures of the working fluid at the related state points are illustrated and discussed. The conclusions obtained in the present paper may provide some theoretical guidance for the optimal parameter design of a class of internal-combustion engines.

关键词： Diesel heat engine irreversibility power output efficiency parameter optimization

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Methods and applications of DEA cross-efficiency: Review and future perspectives

Jie WU, Jiasen SUN, Liang LIANG

《工程管理前沿（英文）》 2021年第8卷第2期页码 199-211 doi: 10.1007/s42524-020-0133-1

摘要： The field of engineering management usually involves evaluation issues, such as program selection, team performance evaluation, technology selection, and supplier evaluation. The traditional self-evaluation data envelopment analysis (DEA) method usually exaggerates the effects of several inputs or outputs of the evaluated decision-making unit (DMU), resulting in unrealistic results. To address this problem, scholars have proposed the cross-efficiency evaluation (CREE) method. Compared with the DEA method, CREE can rank DMUs more completely by using reasonable weights. With the extensive application of this technique, several problems, such as non-unique weights and non-Pareto optimal results, have arisen in CREE methods. Therefore, the improvement of CREE has attracted the attention of many scholars. This paper reviews the theory and applications of CREE, including the non-uniqueness problem, the aggregation of cross-efficiency data, and applications in engineering management. It also discusses the directions for future research on CREE.

关键词： cross-efficiency evaluation efficiency secondary goal model aggregation review