Solubilities, Vapor Pressures, and Heat Capacities of the Water + Lithium Bromide + Lithium Nitrate + Lithium Iodide + Lithium Chloride System

The optimum mole ratio of lithium salts in the H₂O + LiBr + LiNO₃ + LiI + LiCl system was experimentally determined to be LiBr : LiNO₃ : LiI : LiCl = 5 : 1 : 1 : 2. The solubilities were measured at temperatures from 252.02 to 336.75 K. Regression equations on the solubility data were obtained with a least-squares method. Average absolute deviations of the calculated values from the experimental data were 0.15% at temperatures <285.18 K and 0.05% at temperatures 285.18 K. The vapor pressures were measured at concentrations ranging from 50.0 to 70.0 mass% and at temperatures from 330.13 to 434.88 K. The experimental data were correlated with an Antoine-type equation, and the average absolute deviation of the calculated values from the experimental data was 2.25%. The heat capacities were measured at concentrations from 50.0 to 65.0 mass% and temperatures from 298.15 to 328.15 K. The average absolute deviation of the values calculated by the regression equation from the experimental data was 0.24%.     

Physical properties of the lithium bromide + 1,3-propanediol + water system

The experimental measurements of the basic four physical properties (solubility, vapor pressure, density and viscosity) of the lithium bromide + 1,3-propanediol + water system (LiBr/HO(CH₂)₃OH mass ratio = 3.5), a possible new working fluid for absorption heat pump, were carried out. Solubility was measured by the visual polythermal method in the temperature range from 264.65 to 358-95 K, and vapor pressure by the boiling point method from 330.75 to 408.45 K. Densities and viscosities were also measured by using a set of hydrometers and Ubbelohde-type capillary viscometers in the temperature range from 283.15 to 343.15 K. Each measured data set was correlated with a proper equation, and all the correlation results showed good agreement between measured and calculated values. Using the correlation results the Dühring chart was constructed and thus the system was found to be able to have a high absorber temperature, which is essential for the design of air-cooled absorption chiller.     

直燃型溴化锂机组冬季制冷冷剂水不足的排除

先简要介绍了笔者单位直燃型溴化锂机组及其集中控制系统的配置情况以及为防止其中一台机组冬季制冷冷却水温度过低而采取的设计方案,然后针对机组冬季出现的冷剂水不足的故障,分析原因并利用现有条件排除故障,最后总结本故障排除过程中的相关经验。     

冷水机组热回收评价系统的应用分析

随着节能与环保变得越来越重要,许多厂家在冷水机组原有单纯制冷的基础上增加了热回收功能,把原本由冷却塔散掉的废热加以回收利用,主要探讨了该类冷水机组的评价系统,并根据测试实例对该类机组的性能进行了详细的论述。     

新型太阳能热水站与太阳能制冷空调综合系统设计探讨

介绍通过热水需求量来确定空调负荷供应量的太阳能空调和热水站综合系统,建立常年生活热水和夏季空调冷水综合应用的太阳能利用系统.提出几点不足.     

Thermophysical Property Measurements of Supercooled and Liquid Rhodium

The density, the isobaric heat capacity, the surface tension, and the viscosity of liquid rhodium were measured over wide temperature ranges, including the supercooled phase, using an electrostatic levitation furnace. Over the 1820 to 2250 K temperature span, the density can be expressed as (T)=10.82×10³–0.76(T–T _m ) (kgm^–3) with T _m =2236 K, yielding a volume expansion coefficient (T)=7.0×10^–5 (K^–1). The isobaric heat capacity can be estimated as C _P (T)=32.2+1.4×10^–3(T–T _m ) (Jmol^–1K^–1) if the hemispherical total emissivity of the liquid remains constant at 0.18 over the 1820 to 2250 K interval. The enthalpy and entropy of fusion have also been measured, respectively, as 23.0 kJmol^–1 and 10.3 Jmol^–1K^–1. In addition, the surface tension can be expressed as (T)=1.94×10³–0.30(T–T _m ) (mNm^–1) and the viscosity as (T)=0.09 exp[6.4×10⁴(RT)] (mPas) over the 1860 to 2380 K temperature range.     

空调水系统优化方案与离心式冷水机组节能技术

介绍了大温差、小流量空调系统方案和一次泵变流量空调系统方案,这两种方案可节省空调水系统的初投资或运行费,符合空调设计的发展趋势;阐述了具有制冷功能以外,还带有热回收、冰蓄冷、免费取冷等多种功能的先进的离心式冷水机组,其节能效果显著。     

太阳能-空气光伏/光热一体化热泵热水系统实验特性

本文研究了一种新型光伏/光热一体化(PV/T)复合热源热泵热水系统,将多孔扁盒式PV/T集热板与空气源热泵相结合,根据不同控制方式组合成双热源并联、单太阳能和单空气能三种不同运行模式。在室外环境温度28.5℃下,将200 L 30℃热水加热到55℃,研究了加热时间、热水温度、COP等性能的变化规律,结果表明双热源并联运行模式下分别比单太阳能模式和单空气能模式的加热时间缩短了42%和54%,COP分别提高了32.78%和47.64%;同时实验研究了在夏季工况下将200 L水从9∶00循环加热到17∶00过程中系统热性能,探讨了太阳辐射强度、PV/T集热板温度对光电/光热效率的影响,通过实验对比可以得出在热电模式下系统的光电效率η_(pv)比单一光电模式平均高25.8%.     

Experimental Measurements and Theoretical Prediction of the Thermal Conductivity of Two- and Three-Phase Water/Olivine Systems

The thermal conductivity of olivine, dry and mixed with water, up to saturation, has been measured with a thermal probe, using the step heating method. The olivine is composed of solid particles with dimensions in the range from 0.8 to 1 mm. Dry olivine has been measured in the range of temperatures between –17° to +50°C. Olivine mixed with water has been measured at +50°C. The cubic cell model has been used to make predictions to compare with the measured data. Comparisons of the experimental thermal conductivities and the predicted values of dry and water-mixed olivine show good agreement. The cubic cell model can be used to evaluate the porosity of olivine and the thermal conductivity of the solid particles, from the values measured at dryness and saturation, with reasonably good agreement. In this way, it is not necessary to measure the mineral composition of the particles of the porous media. Also, the porosity of the medium is predicted with reasonable agreement, which takes into account the phenomenon of the porosity increase near the probe, since the diameter of the probe is smaller than that of the solid particles.     

Isochoric Heat Capacity Measurements for Light and Heavy Water Near the Critical Point

The isochoric heat capacity was measured for D₂O at a fixed density of 356.075 kg·m^–3 and for H₂O at 309.905 kg·m^–3. The measurements cover the range of temperatures from 623 to 661 K. The measurements were made with a high-temperature, high-pressure, adiabatic calorimeter with a nearly constant inner volume. The uncertainty of the temperature is 10 mK, while the uncertainty of the heat capacity is estimated to be 2 to 3%. Measurements were made in both the two-phase and the one-phase regions. The calorimeter instrumentation also enables measurements of PVT and the temperature derivative (P/T)_V along each measured isochore. A detailed discussion is presented on the experimental temperature behavior of C_V in the one- and two-phase regions, including the coexistence curve near the critical point. A quasi-static thermogram method was applied to determine values of temperature at saturation T_S() on measured isochores. The uncertainty of the phase-transition temperature measurements is about ±0.02 K. The measured C_V data for D₂O and H₂O are compared with values predicted from a recent developed parametric crossover equation of state and IAPWS-95 formulation.     

热水供暖系统经济改造及同程式系统简化水力计算

通过工程实践，总结出室内热水供暖系统垂直单管异程式改造为同程式的经济实用方案；在分析同程式管网传统水力平衡方法后得出，只需计算两根相邻立管间的供、回水干管压降，使供水干管与回水干管压降差值和压差累计值不超过主立管压降的10％，即可实现水力平衡，且达到设计要求；应用中进一步简化为计算图表，有助于提高设计效率。     

无锡某SOHO办公楼水源热泵VRV空调系统设计及分析

对某办公楼空调系统的设计做了多方案比选,最终确定为水源热泵VRV系统方案。对水源热泵VRV系统的设备做了设计选型,对水源热泵VRV的建设模式、节能运行做了讨论,为地产开发商、设计咨询公司、施工企业等提供参考。     

深圳城市供水系统产权结构重组模式及评价

提出了城市供水系统产权结构重组的两种基本模式,运用制度经济学和管理学理论,提出产权结构模式评价的指标与方法,分析了这两种产权结构模式的特性和在这两种模式下不同利益主体的行为与利益关系的变化特点及优缺点,并提出了缓解劣势的手段与方法.     

井水源热泵系统故障检测及解决办法

在现场检测工作的基础上,总结了井水源热泵系统在工程中常出现的一些故障问题,分析了造成故障的原因,并提出了解决的办法;探讨性地提出一些水源热泵系统现场检测和评价方法。     

上海质子重离子医院工艺冷却水及空调水系统节能设计

介绍了该工程的工艺冷却水系统及空调水系统设计中采用的多项节能措施,主要包括工艺一、二次水系统的优化和控制方式以及空调水系统中采用的水源热泵、冷却塔免费供冷等技术手段。     

利用燃气轮机烟气余热的复合有机朗肯循环系统优化分析

本文针对燃气轮机烟气余热设计了一种复合有机朗肯循环系统,对其进行了详细的热力学分析,以某燃驱压气站烟气条件(400℃,26 kg/s)为例,以系统净输出功为目标,利用Matlab和Refprop 9. 0选择了13种工质,并确定了系统最优工况。结果表明,甲苯、R141b、丙酮分别作为3个子系统的工质时,系统可实现最大净输出功为1 587 k W,热效率和火用效率分别可达20. 26%和42. 68%,比单级循环可实现的最大净输出功高23. 33%。对系统各部件进行火用损失分析,发现蒸发器火用损失最大,并提出了改进方案。     

空调系统变水温调节的特性实验及节能分析

针对中、小型中央空调系统，根据空调系统大多数时间处于部分负荷下运行的特点，通过实验，分析了变水温调节时冷水机组和空调系统的运行特性：以实验结果为依据，对中央空调系统的节能潜力进行了分析。