相变蓄热系统放热过程性能实验研究

本文通过对热泵空调系统的相变蓄热冷凝热回收装置进行放热实验,分别测试了不同冷水进水温度和不同水流量下蓄热箱中石蜡及蓄热箱热水出口温度的变化情况。实验结果表明:水流量对石蜡凝固过程的影响较小,提高水流量或者冷水温度可以在一定程度上缩短获取热水时间,但会相应增加能耗;石蜡初始温度提高,石蜡释放显热的速率加快,可以缩短获取热水时间;提高系统的蓄热效率对冷凝热的回收和利用有较大意义。     

Investigation of phase modulation and propagation-route effect from unmatched large-scale structures for Doppler reflectometry measurement through 2D full-wave modeling

To interpret the common symmetric peaks caused by the large-scale structure in the complex S(f) spectrum from the heterodyne Doppler reflectometry(DR) measurement in EAST, a 2D circular-shaped O-mode full-wave model based on the finite-difference time-domain method is built. The scattering characteristics and the influences on the DR signal from various scales are investigated. When the structure is located around the cutoff layer, a moving radial or poloidal large-scale structure k_θ■...     

湖北主网运行特性概况

近年来,随着跨区跨省特高压输电工程的相继投产,500 k V骨干网架的逐步加强及220 k V分区分片运行格局的形成,湖北主网运行特性发生了重大改变。概述了湖北220 k V及500 k V电网的运行特性及存在的问题,同时对未来2~3 a重要特高压及跨区输电工程对湖北电网运行特性的影响进行了介绍。     

典型电网技术降损措施研究及应用

从分析鄂州电网现存的问题入手,介绍了电网经济运行,变压器、线路的降损评价方法,对设备的降损效果进行量化分析。提出调整电网负荷结构、提升无功电压管理、加强配网线损管理等针对鄂州电网的技术降损建议与措施。     

不同冷凝热回收方式下热泵空调动态特性的实验研究

热泵空调系统热回收方式有全部冷凝热回收、部分冷凝热回收和复合冷凝热回收3种形式,实验研究3种形式下,水箱分别采用静态加热和循环加热方式时热泵空调系统的性能。分析并比较各模式下系统制冷能效比、供水温度、系统COP、热回收效率与系统吸排气压力、冷凝温度以及环境温度变量之间的关系。实验结果表明,循环式复合冷凝热回收系统的性能在3种方案中最有优势。     

带冷凝热回收热泵空调器的实验研究

提出了在家用空调器上安装冷凝热回收装置,该系统能够实现热泵热水器、热泵空调器和冷凝热回收功能。实验模拟不同室内外工况和不同运行模式,对整个系统供冷性能和热水供应能力进行了实验研究,并分析了不同空调与热水使用模式对整个系统的影响。最终得到了该系统制冷模式、热水器制热水模式和联合供冷与供热水模式下该系统的压缩机排气压力、压缩机吸气压力、水箱水温变化、制冷量及各个模式下系统性能系数。     

相变蓄热式热泵热水器性能实验研究

对采用纯石蜡相变蓄热式与水蓄热式2种热泵热水器系统的性能进行了对比实验研究,对比分析了2种热泵热水器系统在制冷兼热回收模式下的蓄热过程、蓄热箱的冷凝热回收率以及系统的综合能效系数,在此基础上提出了改善纯石蜡相变蓄热式热水系统性能的措施。实验数据表明,与传统水蓄热式热泵热水系统相比,纯石蜡相变蓄热式热泵热水系统减小了蓄热箱的体积,蓄热过程中系统运行相对平稳,但蓄热箱的换热效果较差、冷凝热回收率相对较低,进而影响了系统的综合能效。可通过对蓄热箱内螺旋盘管进行翅片化处理或者插入铝箔、加入膨胀石墨等项措施强化蓄热箱的传热以提高冷凝热回收率,进而提高系统的综合性能。     

我国地源热泵应用现状及特点分析

介绍了我国地源热泵的应用现状及特点,通过对运用地源热泵工程的实例分析,论证了地源热泵系统的节能环保优势,为地源热泵系统的推广应用提供一些参考.     

X-Mode Frequency Modulated Density Profile Reflectometer on EAST Tokamak

An extraordinary-mode(X-mode) frequency-modulated continuous-wave(FMCW) profile reflectometer has been built on EAST.In the reflectometer,continuous waves with frequency sweeping from 12.5 GHz to 18 GHz were generated through a Hyperabrupt Tuned-varactor Oscillator(HTO) source and a four times active multiplier was used to increase the frequency to V-band(50 GHz to 72 GHz).The polarization of horn lens antenna is perpendicular to the magnetic field line at the edge plasmas.According to the V-band frequency range and polarization,the system cover density range from 0.5 × 1019m 3to 3.0 × 1019m 3(when toroidal magnetic field is 1.8 T),with time resolution of 12.5 ~ 50 μs.The density profile could be calculated by assuming the edge profile through an empirical equation.The maximum spatial error deduced by the method is about 4 cm.This reflectometer has been successfully applied in 2010 autumn EAST campaign,the temporal evolution of density profiles was acquired during the low confinement mode to high confinement mode transition.The density pedestal of EAST Tokamak was observed and the top value and gradient of the density pedestal were estimated.     

Comparison of methods for turbulence Doppler frequency shift calculation in Doppler reflectometer

The Doppler reflectometer(DR), a powerful diagnostic for the plasma perpendicular velocity(u⊥) and turbulence measurement, has been widely used in various fusion devices. Many efforts have been put into extracting the Doppler shift from the DR signal. There are several commonly used methods for Doppler shift extraction, such as the phase derivative, the center of gravity, and symmetric fitting(SFIT). However, the strong zero-order reflection component around 0 k Hz may interfere with the calcula...