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Heat prices for public buildings in Tianjin

Boyuan HAO,Zhe TIAN,Yan DING,Peng PENG

《能源前沿(英文)》 2016年 第10卷 第3期   页码 249-259 doi: 10.1007/s11708-016-0412-z

摘要: Energy-saving awareness of heat users and heating enterprises can be stimulated by implementing heat metering for public buildings and by establishing scientific and reasonable policies for heat prices in China. In this paper, a two-part heat price for public buildings in Tianjin is introduced, which divides the heat price into a basic part and a metering part. According to the statistical analysis of information collected from two pilot heating enterprises, the specific heat load for public buildings in Tianjin is calculated, and three candidate schemes of heat price are proposed. A simulation of heat cost is also conducted, and the benefits for both heat users and heating enterprises are balanced. Finally, the two-part heat price for public buildings in Tianjin is determined: the basic heat price is recommended to be 20 CNY/m , and the metering heat price is recommended to be 76.10 CNY/GJ. Such a price could be implemented in the initial stage of heat metering for public buildings in Tianjin.

关键词: heat metering     public buildings     two-part heat price     specific heat load    

Estimation of composite load model with aggregate induction motor dynamic load for an isolated hybrid

Nitin Kumar SAXENA,Ashwani Kumar SHARMA

《能源前沿(英文)》 2015年 第9卷 第4期   页码 472-485 doi: 10.1007/s11708-015-0373-7

摘要: It is well recognized that the voltage stability of a power system is affected by the load model and hence, to effectively analyze the reactive power compensation of an isolated hybrid wind-diesel based power system, the loads need to be considered along with the generators in a transient analysis. This paper gives a detailed mathematical modeling to compute the reactive power response with small voltage perturbation for composite load. The composite load is a combination of the static and dynamic load model. To develop this composite load model, the exponential load is used as a static load model and induction motors (IMs) are used as a dynamic load model. To analyze the dynamics of IM load, the fifth, third and first order model of IM are formulated and compared using differential equations solver in Matlab coding. Since the decentralized areas have many small consumers which may consist large numbers of IMs of small rating, it is not realistic to model either a single large rating unit or all small rating IMs together that are placed in the system. In place of using a single large rating IM, a group of motors are considered and then the aggregate model of IM is developed using the law of energy conservation. This aggregate model is used as a dynamic load model. For different simulation studies, especially in the area of voltage stability with reactive power compensation of an isolated hybrid power system, the transfer function of the composite load is required. The transfer function of the composite load is derived in this paper by successive derivation for the exponential model of static load and for the fifth and third order IM dynamic load model using state space model.

关键词: isolated hybrid power system (IHPS)     composite load model     static load     dynamic load     induction motor load model     aggregate load    

Absorption heat pump for waste heat reuse: current states and future development

Zhenyuan XU, Ruzhu WANG

《能源前沿(英文)》 2017年 第11卷 第4期   页码 414-436 doi: 10.1007/s11708-017-0507-1

摘要: Absorption heat pump attracts increasing attention due to its advantages in low grade thermal energy utilization. It can be applied for waste heat reuse to save energy consumption, reduce environment pollution, and bring considerable economic benefit. In this paper, three important aspects for absorption heat pump for waste heat reuse are reviewed. In the first part, different absorption heat pump cycles are classified and introduced. Absorption heat pumps for heat amplification and absorption heat transformer for temperature upgrading are included. Both basic single effect cycles and advanced cycles for better performance are introduced. In the second part, different working pairs, including the water based working pairs, ammonia based working pairs, alcohol based working pairs, and halogenated hydrocarbon based working pairs, for absorption heat pump are classified based on the refrigerant. In the third part, the applications of the absorption heat pump and absorption heat transformer for waste heat reuse in different industries are introduced. Based on the reviews in the three aspects, essential summary and future perspective are presented at last.

关键词: absorption     heat pump     heat transformer     waste heat     working pair    

Influence of sprinkler irrigation droplet diameter, application intensity and specific power on flower

Yisheng ZHANG, Delan ZHU

《农业科学与工程前沿(英文)》 2017年 第4卷 第2期   页码 165-171 doi: 10.15302/J-FASE-2017145

摘要: To determine the main parameters of droplet strike damage and avoid flower injury due to the unsuitable practices during sprinkler irrigation, an indoor experiment of irrigation droplet impact on cyclamen was conducted. The influences of different parameters such as droplet diameter, application intensity, specific power on flower strike damage was analyzed using Image Pro-Plus software to compute strike damage area and define damage level by sense-analysis. The results showed that a damage area of <1% represents a safe irrigation level, 1%–3% slight damage level, 3%–6% moderate damage level, and>6% heavy damage level. Equations of application intensity, specific power with sprinkler irrigation time and flower injury ratio were regressed against parameters which cause impact damages. The results indicated that specific power has a significant correlation with injury, and flower damage area increased as the increasing of the value of specific power for the same irrigation time. Application intensity was also correlated with injury when the droplet diameter was larger than 1 mm. When the duration of sprinkler irrigation was 1, 5 and 10 min, the threshold of impinging damage of application intensity was 25.30, 5.01 and 1.64 mm·h and the specific power was 0.467×10 , 9.340×10 and 3.110×10 W·m . These results provide a reference for determining the suitable values of sprinkler properties in operation design.

关键词: application intensity     damage     floriculture     flowers     specific power     sprinkler irrigation    

The combined effects of biomass and temperature on maximum specific ammonia oxidation rate in domestic

《环境科学与工程前沿(英文)》 2021年 第15卷 第6期 doi: 10.1007/s11783-021-1411-9

摘要:

• Actual SAORs was determined using MLVSS and temperature.

关键词: Specific ammonia oxidation rate     Sequencing batch reactor     Biomass     Temperature coefficient     Model simulation    

Effects of radiation and heat source/sink on unsteady MHD boundary layer flow and heat transfer over

Krishnendu Bhattacharyya

《化学科学与工程前沿(英文)》 2011年 第5卷 第3期   页码 376-384 doi: 10.1007/s11705-011-1121-0

摘要: In this paper, an investigation is made to study the effects of radiation and heat source/sink on the unsteady boundary layer flow and heat transfer past a shrinking sheet with suction/injection. The flow is permeated by an externally applied magnetic field normal to the plane of flow. The self-similar equations corresponding to the velocity and temperature fields are obtained, and then solved numerically by finite difference method using quasilinearization technique. The study reveals that the momentum boundary layer thickness increases with increasing unsteadiness and decreases with magnetic field. The thermal boundary layer thickness decreases with Prandtl number, radiation parameter and heat sink parameter, but it increases with heat source parameter. Moreover, increasing unsteadiness, magnetic field strength, radiation and heat sink strength boost the heat transfer.

关键词: MHD boundary layer     unsteady flow     heat transfer     thermal radiation     heat source/sink     shrinking sheet     suction/injection    

Calculation method of load distribution on pipe threaded connections under tension load

Shoujun CHEN, Lianxin GAO, Qi AN

《机械工程前沿(英文)》 2011年 第6卷 第2期   页码 241-248 doi: 10.1007/s11465-011-0219-x

摘要:

This paper presents a new calculation method that can calculate the load distribution on pipe threaded connections under tension load. On the basis of elastic mechanics, the new method was developed by analyzing each thread tooth, and a new deformation and covariant equation by making a mechanics analysis on each thread tooth was obtained. Compared with the traditional method proposed by the previous references, the new deformation and covariant equation could be used to describe the relation between the previous and the next thread tooth. By applying the new method on the sample of P-110S pipe threaded connection, the obtained results show that the load on thread tooth mainly concentrates on the four or five threads engaged and the middle teeth were not utilized well to bear the loads. The model offers a new way to calculate the loads carried on the thread teeth under tension load.

关键词: load distribution     calculation method     pipe threaded connections     tension load    

Heat-spreading analysis of a heat sink base embedded with a heat pipe

B. V. BORGMEYER, H. B. MA,

《能源前沿(英文)》 2010年 第4卷 第2期   页码 143-148 doi: 10.1007/s11708-010-0013-1

摘要: A simplified model predicting the heat transfer performance of a heat sink base with a high thermal conductivity was developed. Numerical analysis was performed using the commercial software FLUENT. The investigation indicates that for heat sink bases with a high effective thermal conductivity, such as the base embedded with a typical heat pipe, the entire heat sink can be modeled as a flat plate with a uniform temperature and an effective convection heat transfer coefficient. This simplified model can be used to determine the heat transfer performance of a heat sink embedded with a typical heat pipe or vapor chamber.

关键词: heat pipe     heat sink     microprocessor heat removal    

Application of entransy dissipation theory in heat convection

Mingtian XU, Jiangfeng GUO, Lin CHENG,

《能源前沿(英文)》 2009年 第3卷 第4期   页码 402-405 doi: 10.1007/s11708-009-0055-4

摘要: In the present work, formulas for calculating the rates of the local thermodynamic entransy dissipation in convective heat transfer in general, and the internal and external flows in particular, are established. Practically, these results may facilitate the application of entransy dissipation theory in thermal engineering. Theoretically they shed light on solving the contradiction of the minimum entropy production principle with balance equations in continuum mechanics.

关键词: entransy dissipation     heat convection     heat exchanger    

Comparison of optimal capacitor placement methods in radial distribution system with load growth andZIP load model

Veera Venkata Satya Naryana MURTY, Ashwani KUMAR

《能源前沿(英文)》 2013年 第7卷 第2期   页码 197-213 doi: 10.1007/s11708-013-0249-7

摘要: In this paper, a combined power loss sensitivity (PLS) index-based approach is proposed to determine the optimal location of the capacitors in the radial distribution system (RDS) based on the real and reactive combined loss sensitivity index, as capacitor placement not only reduces real power loss with voltage profile improvement but also reduces reactive power loss due to the reactive power compensation in the network. The results have been obtained with the existing methods of power loss index (PLI) and index vector (IV) method for comparison. Besides, the optimal placement has been obtained with the proposed method as well as existing methods and the total kVar support has been obtained. In addition, the results of net cost savings for the 10-, 34-, and 69-bus systems are obtained for comparison. Moreover, the results have been obtained for a large system of 85 buses to validate the results with combined sensitivity based approach. Furthermore, the load growth factor has been considered in the study which is essential for the planning and expansion of the existing systems, whereas the impact of the realistic load model as ZIP load model has been considered for the study of all the systems.

关键词: load growth     load models     reactive power compensation     radial distribution system     power loss index (PLI)     power loss sensitivity (PLS)     index vector (IV)    

比能法在渤海海峡隧道TBM 施工中的应用分析

高攀,邹翀

《中国工程科学》 2013年 第15卷 第12期   页码 73-79

摘要:

拟建的渤海海峡隧道采用隧道掘进机(TBM)施工极具挑战性,其中关键之一就是TBM的掘进速率预测问题。本文将渤海海峡隧道和澳大利亚Clem Jones 隧道进行工程类比,并介绍了比能法在Clem Jones 隧道的应用情况。在Clem Jones 隧道施工过程中,相关研究人员运用比能法对TBM的可掘性进行了分析及预测,从后期的掘进情况来看比能法的预测结果与实际施工吻合得较好。本文在Clem Jones 隧道和渤海海峡隧道对比分析的基础上,认为运用比能法预测TBM的可掘性同样适用于渤海海峡隧道的TBM施工。

关键词: TBM     比能     凿岩速率指数     掘进速率    

Experimental investigation of liquid metal alloy based mini-channel heat exchanger for high power electronic

Manli LUO, Jing LIU

《能源前沿(英文)》 2013年 第7卷 第4期   页码 479-486 doi: 10.1007/s11708-013-0277-3

摘要: There is currently a growing demand for developing efficient techniques for cooling integrated electronic devices with ever increasing heat generation power. To better tackle the high-density heat dissipation difficulty within the limited space, this paper is dedicated to clarify the heat transfer behaviors of the liquid metal flowing in mini-channel exchangers with different geometric configurations. A series of comparative experiments using liquid metal alloy Ga68%In20%Sn12% as coolant were conducted under prescribed mass flow rates in three kinds of heat exchangers with varied geometric sizes. Meanwhile, numerical simulations for the heat exchangers under the same working conditions were also performed which well interpreted the experimental measurements. The simulated heat sources were all cooled down by these three heat dissipation apparatuses and the exchanger with the smallest channel width was found to have the largest mean heat transfer coefficient at all conditions due to its much larger heat transfer area. Further, the present work has also developed a correlation equation for characterizing the Nusselt number depending on Peclet number, which is applicable to the low Peclet number case with constant heat flux in the hydrodynamically developed and thermally developing region in the rectangular channel. This study is expected to provide valuable reference for designing future liquid metal based mini-channel heat exchanger.

关键词: heat exchanger     liquid metal     mini-channel     heat dissipation     heat transfer coefficient    

Analysis of flow and heat transfer characteristics of porous heat-storage wall in greenhouse

OUYANG Li, LIU Wei

《能源前沿(英文)》 2008年 第2卷 第4期   页码 406-409 doi: 10.1007/s11708-008-0094-2

摘要: The flow and heat transfer characteristics of porous heat-storage wall in greenhouse are studied by using the one-dimensional steady energy two-equation model for saturated porous medium. The results show that the heat exchange between the air and the solid matrix of the porous heat-storage wall depends upon the inlet air velocity, the porosity and the permeability of porous medium, and the thermal conductivity of the solid matrix. Because the incidence of solar radiation on the porous heat-storage wall is not uniform, the new composite porous solar wall with different porosity is proposed to reduce the disadvantageous effect.

关键词: incidence     thermal conductivity     heat-storage     exchange     composite    

Major applications of heat pipe and its advances coupled with sorption system: a review

Yang YU, Guoliang AN, Liwei WANG

《能源前沿(英文)》 2019年 第13卷 第1期   页码 172-184 doi: 10.1007/s11708-019-0610-6

摘要: Heat pipe utilizes continuous phase change process within a small temperature drop to achieve high thermal conductivity. For decades, heat pipes coupled with novel emerging technologies and methods (using nanofluids and self-rewetting fluids) have been highly appreciated, along with which a number of advances have taken place. In addition to some typical applications of thermal control and heat recovery, the heat pipe technology combined with the sorption technology could efficiently improve the heat and mass transfer performance of sorption systems for heating, cooling and cogeneration. However, almost all existing studies on this combination or integration have not concentrated on the principle of the sorption technology with acting as the heat pipe technology for continuous heat transfer. This paper presents an overview of the emerging working fluids, the major applications of heat pipe, and the advances in heat pipe type sorption system. Besides, the ongoing and perspectives of the solid sorption heat pipe are presented, expecting to serve as useful guides for further investigations and new research potentials.

关键词: heat pipe     sorption system     heat transfer     solid sorption heat pipe    

A practical multi-lane factor model of bridges based on multi-truck presence considering lane load disparities

《结构与土木工程前沿(英文)》 2021年 第15卷 第4期   页码 877-894 doi: 10.1007/s11709-021-0756-2

摘要: Many bridge design specifications consider multi-lane factors (MLFs) a critical component of the traffic load model. Measured multi-lane traffic data generally exhibit significant lane disparities in traffic loads over multiple lanes. However, these disparities are not considered in current specifications. To address this drawback, a multi-coefficient MLF model was developed based on an improved probabilistic statistical approach that considers the presence of multiple trucks. The proposed MLF model and approach were calibrated and demonstrated through an example site. The model sensitivity analysis demonstrated the significant influence of lane disparity of truck traffic volume and truck weight distribution on the MLF. Using the proposed approach, the experimental site study yielded MLFs comparable with those directly calculated using traffic load effects. The exclusion of overloaded trucks caused the proposed approach, existing design specifications, and conventional approach of ignoring lane load disparity to generate comparable MLFs, while the MLFs based on the proposed approach were the most comprehensive. The inclusion of overloaded trucks caused the conventional approach and design specifications to overestimate the MLFs significantly. Finally, the benefits of the research results to bridge practitioners were discussed.

关键词: bridges     multi-lane factor     traffic load     lane load disparity     multi-truck presence     weigh-in-motion data    

标题 作者 时间 类型 操作

Heat prices for public buildings in Tianjin

Boyuan HAO,Zhe TIAN,Yan DING,Peng PENG

期刊论文

Estimation of composite load model with aggregate induction motor dynamic load for an isolated hybrid

Nitin Kumar SAXENA,Ashwani Kumar SHARMA

期刊论文

Absorption heat pump for waste heat reuse: current states and future development

Zhenyuan XU, Ruzhu WANG

期刊论文

Influence of sprinkler irrigation droplet diameter, application intensity and specific power on flower

Yisheng ZHANG, Delan ZHU

期刊论文

The combined effects of biomass and temperature on maximum specific ammonia oxidation rate in domestic

期刊论文

Effects of radiation and heat source/sink on unsteady MHD boundary layer flow and heat transfer over

Krishnendu Bhattacharyya

期刊论文

Calculation method of load distribution on pipe threaded connections under tension load

Shoujun CHEN, Lianxin GAO, Qi AN

期刊论文

Heat-spreading analysis of a heat sink base embedded with a heat pipe

B. V. BORGMEYER, H. B. MA,

期刊论文

Application of entransy dissipation theory in heat convection

Mingtian XU, Jiangfeng GUO, Lin CHENG,

期刊论文

Comparison of optimal capacitor placement methods in radial distribution system with load growth andZIP load model

Veera Venkata Satya Naryana MURTY, Ashwani KUMAR

期刊论文

比能法在渤海海峡隧道TBM 施工中的应用分析

高攀,邹翀

期刊论文

Experimental investigation of liquid metal alloy based mini-channel heat exchanger for high power electronic

Manli LUO, Jing LIU

期刊论文

Analysis of flow and heat transfer characteristics of porous heat-storage wall in greenhouse

OUYANG Li, LIU Wei

期刊论文

Major applications of heat pipe and its advances coupled with sorption system: a review

Yang YU, Guoliang AN, Liwei WANG

期刊论文

A practical multi-lane factor model of bridges based on multi-truck presence considering lane load disparities

期刊论文