Cycle analysis using exhaust heat of SOFC and turbine combined cycle by absorption chiller

The power generating efficiency of solid oxide fuel cell (SOFC) and gas turbine combined cycle is fairly high. However, the exhaust gas temperature of the combined cycle is still high, about 300^°C. Thus, it should be recovered for energy saving, for example, by absorption chiller. The energy demand for refrigeration cooling is recently increasing year by year in Japan. We propose here a cogeneration system by series connection of SOFC, gas turbine and LiBr absorption chiller to convert the exhaust heat to the cooling heat. As a result of cycle analysis of the combined system with 500‐kW‐class SOFC, the bottoming single‐effect absorption chiller can produce a refrigerating capacity of about 120 kW, and the double‐effect absorption chiller can produce a little higher refrigerating capacity of about 130 kW without any additional fuel. But the double‐effect absorption chiller became more expensive and complex than the single‐effect chiller. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 167(1): 49– 55, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20578     

以总能系统观点与用热终端高效化为特征的大中型火电机组联产供热系统新模式

以总能系统观点为指导,本文把联产供热系统视为由六个子系统组成,提出了各子系统火用效率的计算方法和这些效率对供热煤耗和成本的影响,并在此基础上提出了能适用于大中型火电机组的热电联产供热系统的新模式。新模式以用热终端高效化为特征,带动提高一系列子系统的火用效率,并把行之有效的,但一般是小规模孤立使用的现代化节能技术与节能设备,大规模地有机地与热电联产系统融为一体,扩大热网水的降温幅度,对热网水低品位能量进行梯级利用,形成采暖节能与增供电力相互促进相得益彰的机制,使联产供热的煤耗和供热成本大幅度地降低。文中结合世界技术现状和我国经济发展阶段分析了新模式的现实可行性。     

Energy Conservation in Urban Areas

This article outlines the energy conservation measures in the civilian sector from a few different viewpoint regarding energy conservation in cities. First, the energy consumption trends in the business and residential sectors are discussed, focusing the importance of energy conservation measures in applications such as home heating, water heating and specific power demand. Second, as a measure to reduce energy demand itself, energy conservation by way of applying heat insulating materials to buildings and changing the life style of residents is considered. And from the viewpoint of improving the energy system efficiency, additionally discussed here are the measures to improve the efficiency of each energy equipment such as air‐conditioners and co‐generation equipment, and the characteristics of District heating and cooling systems such as the local energy infrastructures. Lastly, from the knowledge obtained through model analyses by the authors, a scheme is recommended that would be one of the most efficient city‐energy schemes where the energy systems including heat pumps, co‐generators or equipment using solar power are utilized for their best‐suited applications for business and residential customers. Copyright © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Characteristics and economic evaluation of a CO2‐capturing solar thermal hybrid power generation system with heat storage

For wide use of a power plant utilizing solar energy, improvement of its economics is important. Both the economics and characteristics of a CO₂‐capturing solar thermal hybrid power generation system are evaluated in this paper. Since a relatively low temperature steam of 220 °C is produced by using solar thermal energy and is utilized as the working fluid of a gas turbine, the solar collector can attain high heat collecting efficiency. The net fuel‐to‐electricity conversion efficiency of the hybrid system is estimated to be higher than 60% on the lower‐heating‐value‐ basis. It has been estimated that the gross income and the period of depreciation of the proposed system are 34.8 × 10⁵ yen/year and 8.89 years, respectively, and that the system is economically feasible, under the assumptions of a solar collector area of 10 ha, a maximum net power output of 4 MW, and a heat storage capacity of 2000 m³. The amount of fuel saving and reduction of CO₂ emission of our system, compared to a conventional natural gas firing plant, are also estimated in the paper. © 1999 Scripta Technica, Electr Eng Jpn, 126(4): 21–29, 1999     

Open‐cycle OTEC systems with freshwater product: Effects of noncondensable gases on performance of condenser

An open‐cycle ocean thermal energy conversion (OC‐OTEC) system is one of the energy conversion methods used to generate electricity from ocean thermal energy. For the OC‐OTEC system, steam evaporated from the surface seawater due to flash evaporation drives the turbine. At that time, dissolved gas such as air is introduced into the low‐pressure system (OC‐OTEC system) as the noncondensable gas, which degrades the performance of condensation heat transfer. In this paper, a small‐scale OC‐OTEC experimental unit experimentally investigates the effect of noncondensable gas on the heat transfer performance in a condenser. The experimental results are discussed in comparison with theoretical estimation by the Sparrow–in method. It is shown that the condensation is occupied by heat and mass transfer near a condensation surface and that the condensation efficiency is affected by exhaust quantity of noncondensable gas at a relatively high concentration ratio of condensable gas. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 154(1): 29–35, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20179     

某大型公共建筑分布式能源系统集成与优化运行研究

以某大型公共建筑分布式能源系统为例,根据其冷、热、电负荷特性,对基于燃气轮机和燃气内燃机2种类型的分布式能源系统的经济效益评估进行分析,提出了“燃气冷热电三联供系统加电制冷机组加燃气锅炉加蓄能系统”的整体设计方案。选择冷热电三联供系统的配置,分析其系统集成与优化运行控制策略,并将其与燃气直燃型一体化机组进行经济性和节能性对比,结果表明其平均能源综合利用效率为82．5％,供热经济性优势明显,但投资回收效果不理想。     

考虑㶲损失的三联供系统容量配置与运行模式研究

节能减排一直是世界各国持续关注的热点问题,综合能源三联供系统因其具有更高的一次能源利用率而被广泛应用。针对综合能源三联供系统的容量配置和运行模式规划问题,提出考虑(火用)损失的综合性能指标作为优化的目标函数,从高效、低碳、经济三个方面进行综合优化。以燃气轮机的容量和运行模式为设计变量,建立综合能源三联供系统容量配置与运行模式研究模型。将此方法应用到某宾馆建筑的联供系统进行分析,研究结果为：燃气轮机的最佳容量为200 kW,热电结合是最优的运行模式。在该模式下综合能源三联供系统较传统供能系统(火用)损失率降低3.5%,年综合碳排量减少593.7 t,年经济成本节约29.8万元。该方法能够全面、客观地分析某容量、某种运行模式下的系统性能,为解决联供系统的运行规划问题提供参考。     

吸附式制冷热泵及其在冷热电联供系统应用的能源利用分析

从能源利用率的角度 ,用当量热力系数及能源利用系数分析比较了吸附式空调热泵构成的冷热电联供系统。采用吸附制冷热泵的三联供系统以提高能源利用率是可行的 ,但在系统的构成上 ,吸附热力系统必须采用高效机组     

CO2 reduction effect of the utilization of waste heat and solar heat in a city gas system

We evaluated total energy consumption and CO₂ emissions in the phases of a city gas utilization system from obtaining raw materials to consuming the product. Assuming monthly and hourly demand figures for electricity, heat for space heating, and hot water in a typical hospital, we explore the optimal size and operation of a city gas system that minimizes the life cycle CO₂ emissions or total cost. The cost‐effectiveness of conventional cogeneration, a solar heating system, and hybrid cogeneration utilizing solar heat is compared. We formulate a problem of mixed integer programming that includes integral parameters that express the state of system devices such as the on/off condition of switches. As a result of optimization, the hybrid cogeneration can reduce annual CO₂ emissions by 43% compared with the system without cogeneration. The sensitivity of CO₂ reduction and cost to the scale of the CGS is also analyzed. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 149(1): 22–32, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10369     

小热电的评价及热电厂经济指标的探讨

依据我国的能源政策,阐述了小热电机组与小火电机组的区别;分析了热电联产的优越性;论述了热电联产在节能降耗,环境保护及电网调峰中产生的社会效益和经济效益,并结合我国的实际,对热电厂的考核指标进行了探讨,对改善小热电的建设与运行提出了建议。     

具有独立冷却系统的电容器真浸设备

缩短电容器真浸工艺时间及节能降耗是行业内每个厂家追求的目标。介绍一种电容器内冷式真浸设备结构、连接方式及采取的具体措施。电容器内冷式真浸设备的显著特点是具有真空干燥加热和真空快速降温相互独立的两个系统,成功地解决了真空与降温,＂传质过程＂和＂传热过程＂之间的矛盾。电容器内冷式真浸设备良好的降温功能大大缩短了降温时间,继而保证真空阶段维持正常的加热温度,最终达到缩短时间,节能降耗,保证质量的双赢效果,是电容器制造行业一种可以推广应用的新技术。     

Proposal and evaluation of a gas engine and gas turbine hybrid cogeneration system in which cascaded heat is highly utilized

A high‐efficiency cogeneration system (CGS) is proposed for utilizing high‐temperature exhaust gas (HTEG) from a gas engine (GE). In the proposed system, for making use of heat energy of HTEG, H₂O turbine (HTb) is incorporated and steam produced by utilizing HTEG is used as working fluid of HTb. HTb exhaust gas is also utilized for increasing power output and for satisfying heat demand in the proposed system. Both of the thermodynamic characteristics of the proposed system and a gas engine CGS (GE‐CGS) constructed by using the original GE are estimated. Energy saving characteristics and CO₂ reduction effects of the proposed CGS and the GE‐CGS are also investigated. It was estimated that the net generated power of the proposed CGS has been increased 25.5% and net power generation efficiency 6.7%, compared with the original GE‐CGS. It was also shown that the proposed CGS could save 27.0% of energy consumption and reduce 1137 t‐CO₂/y, 1.41 times larger than those of GE‐CGS, when a case study was set and investigated. Improvements of performance by increasing turbine inlet temperature were also investigated. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 166(3): 37– 45, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20708     

燃气轮机冷热电联产系统与蓄能变工况特性

利用单轴恒速燃气轮机典型变工况计算方法和余热锅炉考虑换热系数的变工况计算方法，对冷热电联产系统的变工况进行了分析：高负荷时联产系统有明显的节能优势；但随负荷的降低，优势不断减少；在负荷降低到一定程度之后已经不如参照系统性能。为改善系统全工况性能，可将联产系统与蓄能技术有机结合。依靠对某建筑典型夏、冬季全天冷、热负荷供应进行分析，可以看到蓄能的使用使联产系统的节能率在较高基础上进一步得到提高。     

Development of NbTi superconducting strands and cables for the field winding of a 200‐MW‐class high‐energy‐density superconducting generator

The NbTi superconducting strands and cables for the field winding of the 200‐MW‐class high‐energy‐density‐type superconducting generator are developed. They are composed of Cu/Cu‐10wt%Ni/Nb‐46.5wt%Ti superconducting strands and the 10‐kA (at 5 T)‐class 9‐strand compacted cables. The diameter of strands is 1.33 mm, and the 9‐strand compacted cables are 2.4 mm thick and 6.0 mm wide. In order to produce high‐current‐density NbTi strands, we made strands under controlled aging heat treatments, the total and final strains, and the strains between heat treatments, by using large‐scale extruder. Moreover, in order to produce high‐stability and low‐AC‐loss NbTi strands and cables, the matrix ratio of strands and the cross sections of strands are optimized. The current density of NbTi filaments for the four‐time‐aging manufactured 1.33‐mm‐diameter strands was J_C=3150 A/mm² at 5 T, 1150 A/mm² at 8 T. The critical current of the 9‐strand compacted cable is 10.7 kA at 5 T. The AC losses of the final compacted cables are less than 100 kW/m³ at 5 T, 5 T/s, that is, decreased to less than half of the target of the AC loss value (< at 5 T, 5 T/s). Compared with the strand (Cu ratio 1.77), the minimum quench energy (MQE) of the strand (Cu ratio>2) increased about 40% at the operation mode current of the superconducting generator. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 156(3): 24– 31, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20266     

波导手机维修精选

无按键灯故障通常分两种情况：一种是单个按键灯不亮；另一种是所有按键灯均不亮。     

园区型综合能源系统节能效果及优化运行分析

随着综合能源系统在国内的快速发展,对综合能源系统际运行后的节能效果评价日趋重要。分析了园区型综合能源系统节能效果及其优化运行手段,该园区型综合能源系统包括光伏发电系统、地源热泵系统、太阳能空调系统、蓄热式电锅炉系统及太阳能热水系统等。建立了各子系统的节能效益计算模型,根据各子系统的运行历史数据,对各子系统的计算结果进行了分析。结果表明：太阳能光伏发电系统节能收益主要来自第二、第三季度,应在此期间注意光伏组件的维护保养,保证节能效益最大化;地源热泵系统夏季节能效果并不显著,在夏季可与传统机组协同供冷;园区冬季供热是由地源热泵系统、蓄热式电锅炉系统和太阳能空调系统综合提供,节能效果显著,是园区节能收益的主要来源。     

火电厂湿冷与空冷系统水泵风机的节能改造

简述了火电湿冷系统循环水泵的存在问题、技改措施及节能效果。详述了火电厂间接空冷系统循环水泵及其在系统中的连接特点、能耗情况、出现问题及改进措施，以及火电厂直接空冷系统的风机群体的能耗情况、运行方式、节能措施等。     

The heat supply system for a self-contained dwelling house on the basis of a heat pump and wind power installation

Matters concerned with setting up environmentally clean supply of heat to dwelling houses in the resort zone of the Russian Black Sea coast on the basis of air-water type heat pumps powered from wind power installations are discussed. The investigations were carried out as applied to the system supplying heat for an individual dwelling house with an area of around 300 m² situated in the Tuapse city. The design heat load of the building’s heating system is around 8.3 kW. The Viessmann Vitocal 300 AW pump is chosen as the main source of heat supply, and a 4-kW electric heater built into a storage tank is chosen as a standby source. The selected wind power installation (the EuroWind 10 unit) has a power capacity of 13 kWe.     

热泵技术在集中供热系统中的应用

电厂生产过程中存在各种热损失,尤其是循环冷却水携带的大量低位热能,在实际生产中很难直接再利用,往往直接排放到空气中,造成了环境的热污染和能源的浪费。热泵作为一种利用低温热源的节能装置,在余热回收和提高能源利用率方面日趋重要。结合热泵回收低温余热技术,分析了对集中供热系统进行节能改造的必要性和可行性,提出了利用汽轮机抽汽驱动吸收式热泵回收电厂循环水废热来初步预热供热回水的集中供热方法。经过技术经济性分析,证明此方法可行,具有环保、节能、节水等多重功效。     

350MW超临界汽轮机低位能供热技术节能分析

传统的热电联产抽汽供热方式供热能力低、电量损失大、机组综合能耗高、(火用)效率低。采用湿冷机组低位能分级加热供暖技术对350 MW超临界供热机组进行节能改造。运行结果表明：在相同的主蒸汽量条件下,改造后供热能力增加35%、发电功率增加8%以上;在年供暖量增加188.65万GJ的同时,供热期发电量增加83.9 GW·h,供热期效益年增长约9 341.6万元。改造后社会节煤12.69万t,CO₂减排33万t。