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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    

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    

Advancing performance assessment of a spectral beam splitting hybrid PV/T system with water-based SiO

《能源前沿(英文)》 doi: 10.1007/s11708-024-0933-11

摘要: Spectral beam split is attracting more attention thanks to the efficient use of whole spectrum solar energy and the cogenerative supply for electricity and heat. Nanofluids can selectively absorb and deliver specific solar spectra, making various nanofluids ideal for potential use in hybrid photovoltaic/thermal (PV/T) systems for solar spectrum separation. Clarifying the effects of design parameters is extremely beneficial for optimal frequency divider design and system performance enhancement. The water-based SiO2 nanofluid with excellent thermal and absorption properties was proposed as the spectral beam splitter in the present study, to improve the efficiency of a hybrid PV/T system. Moreover, a dual optical path method was applied to get its spectral transimissivity and analyze the impact of its concentration and optical path on its optical properties. Furthermore, a PV and photothermal model of the presented system was built to investigate the system performance. The result indicates that the transimissivity of the nanofluids to solar radiation gradually decreases with increasing SiO2 nanofluid concentration and optical path. The higher nanofluid concentration leads to a lower electrical conversion efficiency, a higher thermal conversion efficiency, and an overall system efficiency. Considering the overall efficiency and economic cost, the optimal SiO2 nanofluid concentration is 0.10 wt.% (wt.%, mass fraction). Increasing the optical path (from 0 to 30 mm) results in a 60.43% reduction in electrical conversion efficiency and a 50.84% increase in overall system efficiency. However, the overall system efficiency rises sharply as the optical path increases in the 0–10 mm range, and then slowly at the optical path of 10–30 mm. Additionally, the overall system efficiency increases first and then drops upon increasing the focusing ratio. The maximum efficiency is 51.93% at the focusing ratio of 3.

关键词: full-spectrum solar energy     photovoltaic/thermal (PV/T) system     water-based nanofluid     system efficiency    

Advancing performance assessment of a spectral beam splitting hybrid PV/T system with water-based SiO

《能源前沿(英文)》 doi: 10.1007/s11708-024-0935-7

摘要: Spectral beam split is attracting more attention thanks to the efficient use of whole spectrum solar energy and the cogenerative supply for electricity and heat. Nanofluids can selectively absorb and deliver specific solar spectra, making various nanofluids ideal for potential use in hybrid photovoltaic/thermal (PV/T) systems for solar spectrum separation. Clarifying the effects of design parameters is extremely beneficial for optimal frequency divider design and system performance enhancement. The water-based SiO2 nanofluid with excellent thermal and absorption properties was proposed as the spectral beam splitter in the present study, to improve the efficiency of a hybrid PV/T system. Moreover, a dual optical path method was applied to get its spectral transimissivity and analyze the impact of its concentration and optical path on its optical properties. Furthermore, a PV and photothermal model of the presented system was built to investigate the system performance. The result indicates that the transimissivity of the nanofluids to solar radiation gradually decreases with increasing SiO2 nanofluid concentration and optical path. The higher nanofluid concentration leads to a lower electrical conversion efficiency, a higher thermal conversion efficiency, and an overall system efficiency. Considering the overall efficiency and economic cost, the optimal SiO2 nanofluid concentration is 0.10 wt.% (wt.%, mass fraction). Increasing the optical path (from 0 to 30 mm) results in a 60.43% reduction in electrical conversion efficiency and a 50.84% increase in overall system efficiency. However, the overall system efficiency rises sharply as the optical path increases in the 0–10 mm range, and then slowly at the optical path of 10–30 mm. Additionally, the overall system efficiency increases first and then drops upon increasing the focusing ratio. The maximum efficiency is 51.93% at the focusing ratio of 3.

关键词: full-spectrum solar energy     photovoltaic/thermal (PV/T) system     water-based nanofluid     system efficiency    

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    

Advances in catalysts and reaction systems for electro/photocatalytic ammonia production

《化学科学与工程前沿(英文)》 doi: 10.1007/s11705-024-2463-8

摘要: Ammonia is a vital component in the fertilizer and chemical industries, as well as serving as a significant carrier of renewable hydrogen energy. Compared with the industry’s principal technique, the Haber-Bosch method, for ammonia synthesis, electro/photocatalytic ammonia synthesis is increasingly recognized as a viable and eco-friendly alternative. This method enables distributed small-scale deployment and can be powered by sustainable renewable energy sources. However, the efficiency of electro/photocatalytic nitrogen reduction reaction is hindered by the challenges in activating the N≡N bond and nitrogen’s low solubility, thereby limiting its large-scale industrial applications. In this review, recent advancements in electro/photocatalytic nitrogen reduction are summarized, encompassing the complex reaction mechanisms, as well as the effective strategies for developing electro/photocatalytic catalysts and advanced reaction systems. Furthermore, the energy efficiency and economic analysis of electro/photocatalytic nitrogen fixation are deeply discussed. Finally, some unsolved challenges and potential opportunities are discussed for the future development of electro/photocatalytic ammonia synthesis.

关键词: ammonia synthesis     electro/photocatalysis     nitrogen fixation     reaction system     economic and efficiency analysis    

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    

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    

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    

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    

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    

基于实际RIS功耗模型的RIS辅助多小区通信系统能量效率优化 Research Article

许丹宁,韩瑜,李潇,王静赫,金石

《信息与电子工程前沿(英文)》 2023年 第24卷 第12期   页码 1717-1727 doi: 10.1631/FITEE.2300136

摘要: 可重构智能超表面(RIS)是一种被广泛认可能够辅助基站与边缘用户之间通信的潜在技术。本文基于实际的RIS功耗模型,研究了RIS辅助多小区通信系统的能量效率。为了最大化系统的能量效率,提出一种交替优化算法,该算法联合优化了基站处的发射波束成形向量和RIS相移矩阵。首先,通过求解转换后的加权最小均方误差问题,对发射波束成形向量进行优化。随后,为解决RIS单元功耗与其离散相移之间的离散关系所导致的计算困难问题,使用一个连续函数来近似它们的关系。利用这种近似关系,采用优化最小化(MM)算法来优化连续的RIS相移,然后将得到的相移量化为离散相移。仿真结果表明,该算法有效提升了系统的能量效率。

关键词: 可重构智能超表面;能量效率;多小区通信系统    

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    

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    

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    

标题 作者 时间 类型 操作

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

Yazdan DANESHVAR, Majid SABZEHPARVAR, Seyed Amir Hossein HASHEMI

期刊论文

Basic model study on efficiency evaluation in collaborative design work process

XIE Qiu, YANG Yu, LI Xiaoli, ZHAO Ningyu

期刊论文

Advancing performance assessment of a spectral beam splitting hybrid PV/T system with water-based SiO

期刊论文

Advancing performance assessment of a spectral beam splitting hybrid PV/T system with water-based SiO

期刊论文

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

期刊论文

Advances in catalysts and reaction systems for electro/photocatalytic ammonia production

期刊论文

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

Qingxian AN, Xuyang LIU, Shijie DING

期刊论文

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

Peng GAO, Liwei WANG, Ruzhu WANG, Yang YU

期刊论文

Characteristics and application of road absorbing solar energy

Zhihua ZHOU, Shan HU, Xiaoyan ZHANG, Jian ZUO

期刊论文

A NEW APPROACH TO HOLISTIC NITROGEN MANAGEMENT IN CHINA

期刊论文

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

La ZHUO, Arjen Y. HOEKSTRA

期刊论文

基于实际RIS功耗模型的RIS辅助多小区通信系统能量效率优化

许丹宁,韩瑜,李潇,王静赫,金石

期刊论文

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

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

期刊论文

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

null

期刊论文

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

期刊论文