复合型热泵在商住楼中的应用

针对商住楼,提出了一种复合型热泵系统。在夏季,该系统给室内供冷的同时利用热回收制备生活热水,在环境温度较高时,利用生活给水带走一部分冷凝热;在冬季,该系统既可以制备生活热水,也能给室内供热,在环境温度较低时,利用消防水池的水作为热源,实现了设备本身和建筑物内水资源的充分利用,从而保证热泵常年都有较高的能效值。     

同程式垂直单管供热系统寻求最不利用户的方法

应用图论理论建立枝状管网水力工况模拟分析的数学模型,基于该模型和供热管网的热力工况模型,研究分析热水供热系统由于水力工况水平失调和垂直失调对热特性的影响,找出供热系统的最不利用户,为控制系统监测点的布置打下基础。     

基于智能算法与动态仿真的供热智能引擎构建

智慧供热是基于区域供热系统的一种现代供热方式,是我国供热行业未来发展的重要方向。智能决策网作为智慧供热的核心系统,对实现智慧供热有着至关重要的作用。基于智能算法和动态仿真的有效融合,提出了构建供热系统智能引擎的技术路线。阐述了智能算法和动态仿真在智能决策网各核心功能模块(供热管网监测点优化布置、热负荷预测、水力仿真模型与模型参数校准、热动态模型、供热管网泄漏故障诊断)开发中的应用方法。该技术路线可以为智能决策网的研发提供理论指导。     

麻省理工研发新型太阳热光伏发电系统

<正>近日,美国麻省理工学院研究人员开发了一种新型的太阳热光伏发电系统。该系统在太阳电池外面安装了一个由碳纳米管和光子晶体等组成两层的吸收-释放装置。该装置外层的受光面是一排多壁碳纳米管,能有效吸收太阳光并将其转化为热,加热紧紧依附在其上的光子晶体,使光子晶体会"发出"最高密度几乎与太阳电池带隙相吻合的光,确保被吸收器收集的大部分能量转化为     

严寒地区集中供热系统节能控制研究

本论文以长春某宾馆为研究对象,提出了一套应用于集中供热系统的节能方案和控制策略。该方案利用污水源热泵,提取污水中的热量用于集中供热系统中,有效的节约了能源。再辅以智能控制技术,实时监控室内外温度变化,通过调整供热机组功率,能在保证供热效果的前提下,明显降低供热所需能量,实现集中供热系统的节能运行。     

一种新型地热井下换热器-热泵联用供热系统的热力分析

建立了该供热系统的热力学模型,推导出了供热负荷与设计参数、运行参数、环境温度的关系式.通过理论计算,分析了添加热泵与未加热泵两种工况下,散热器表面积、循环水流量、环境温度等对井下换热器性能及供热系统供热量的影响.     

管网质调节运行时散热器的动态热过程分析

在区域供热系统设计中,通常采用概算指标法确定热负荷,以作为末端用户散热器的选择依据,很少涉及供热房间的动态热过程。本文考虑供热系统末端散热器的实际换热过程,将散热器划分多个控制体建立动态热量交换模型,并进行数值模拟和相应的实验验证。通过输入管网供热参数和室外气候条件,模拟室内环境温度的变化,并实时反馈供热管网的回水温度。由此探讨供暖房间与供热系统之间相关参数的关联关系,为实现管网实时控制提供末端用户的热动态参数。     

建筑物热力入口热量供需平衡调节方法

采暖系统水平失调是建筑供热的常见现象,从而导致供热系统供热量往往与建筑热负荷不配备,因此如何使供热量按需调节对建筑采暖节能降耗具有至关重要的作用。为解决该问题,本文针对散热器采暖系统,提出了基于能量平衡法的供热系统热量调节方法,并在一个办公建筑中实现了工程应用,分析了采暖系统常数的实验获取方法,实验研究了能量平衡法对建筑室内平均温度控制的效果,并与利用入口温度调节时的室内平均温度进行了比较。结果表明,基于能量平衡法可以稳定地控制建筑室内平均温度,与采用入口温度调节的方法相比,基于能量平衡法调节供热量时,建筑室内平均温度的波动较小。     

利用水源热泵吸收热电厂冷凝热——国阳新能集中供热工程案例

为解决火力发电厂冷凝热排向大气造成能量浪费的问题,国阳新能集中供热工程利用大型高温水源热泵回收热电厂冷凝热进行供热。介绍了热电厂冷凝热的特点和该工程的设计方案。分析表明,该方案能提高热电厂热效率,产生可观的经济效益、环境效益和社会效益,实现节能减排。     

供热机组-海水淡化联合生产系统经济性研究

供热机组-海水淡化联合生产是一种新型能量转换系统,实现了能量的梯级利用,本文介绍了整个系统的工艺流程,采用等效热降的方法分析了供热机组的各项经济指标,并分别应用ELWP和CW两种方法计算了联合生产情况下海水淡化的成本。分析计算结果表明联合生产不仅全厂热效率比纯凝气工况高12％,海水淡化成本也较低,具有推广应用价值。在计算过程中发现ELWP考虑了抽汽能量的品质,是比较精确的成本计算方法。     

A review on performance improvement of an absorption refrigeration system by modification of basic cycle

The vapour absorption refrigeration system is not so much used commercially because of its low performance. The performance of an absorption refrigeration system is required to make it an efficient alternative of vapour compression refrigeration systems. This paper reviews different research on modification of absorption systems contributing to enhance the performance of absorption refrigeration systems. This study suggests that the performance of absorption refrigeration is improved by using double-effect and semi-generator absorber solution heat exchanger arrangement. The coefficient of performance of absorption refrigeration is also improved by the combination of different refrigeration cycles (hybrid refrigeration cycle) such as compression–absorption and ejector–absorption.

Abbreviations: COP: coefficient of performance; GAX: generator absorber solution heat exchanger; ARS: absorption refrigeration system; ECOP: ecological coefficient of performance; CAHP: compression-assisted absorption heat pump     

120～150℃热水用于双效吸收制冷循环热力分析

针对集中供热热水用于溴化锂吸收式制冷时的温度不匹配问题,提出在双效并联循环中增加一个加压装置的办法,通过补偿一部分电能以扩大双效循环对热源温度的适用范围,从而使得双效溴化锂吸收式制冷可以使用集中供热一次热源作为驱动能源。经过分析,加压装置安装在蒸发器与吸收器之间效果最好,但安装在高发与低发之间蒸汽压缩量最少。     

Computer modelling and thermodynamic assessment of an aqua-ammonia absorption cycle solar heat pump

An assessment based on steady state thermodynamic analysis of an aqua-ammonia absorption cycle solar heat pump for space heating is presented. The system consists of a solar heated generator, rectifier, condenser, evaporator, absorber liquid heat exchanger and a subcooler. During heat pump operation, the evaporator absorbs heat at low temperature from the outside atmospheric air, while the heat rejected by the absorber, condenser and rectifier is used to warm the interior air of the space to be heated. A numerical computer modelling based on the solution of simultaneous heat and mass balance equations for various components of the system has been carried out. The influences of component temperatures and heat exchanger effectiveness on the heating coefficients of performance and heat transfer rates have been investigated to obtain optimum operating conditions for the proposed heat pump system. Further, the absorption cycles are compared with an ideal reversible cycle operating over the same range of temperatures. It has been found that the performance of the absorption cycle does not continue to improve as the input temperature increases and that additional components will be required to allow the machine to take advantage of the higher temperatures available from modern collectors.     

Experimental investigation of the solar cooker during sunshine and off-sunshine hours using the thermal energy storage unit based on a parabolic trough collector

A solar cooker based on a parabolic trough collector with thermal energy storage (TES) was investigated. In this experimental set-up, solar radiations were focused on the absorber tube and the collected heat was transferred to the solar cooker by natural circulation (thermosiphon) of the working fluid. The water and thermal oil (engine oil) were used separately as working fluids. Acetanilide was used as the TES material in the solar cooker. In day time, the phase change material (PCM) stored heat as well as transferred it to the cooking pot. In evening time, the stored energy by PCM was used to cook the food. The cooking process was carried out with different foods and with variation in the quantity of food. It was found that the temperature of thermal oil was 10–24°C higher than water as the working fluid. The system was able to cook the food twice a day and the rate of evening cooking was higher as compared with noon cooking. Using thermal oil as the working fluid, the quantity of heat stored by PCM was increased by an amount of 19.45–30.38% as compared with water.     

吸收压力、溶液浓度、冷却水温度和流量对溴化锂吸收式制冷机吸收过程的影响

建立了溴化锂吸收式制冷机吸收器内溶液吸收过程的数学模型,并用计算机进行了求解,根据数值解和实验结果,分析了吸收压力,溶液浓度,冷却水温度和流量对吸收吸收效果和传热性能的影响。     

空气换热器在冷却顶板空调系统中的节能潜力

分析计算了采用不同空气换热器组合方案时CC/DV系统和CC/MV系统的新风能耗,指出两个空气热回收装置组合使用可以消除新风再热能耗,但在夏季湿热地区,排风潜热回收比消除新风再热能耗更重要,应尽可能使用全热空气换热器。     

Optimisation of electronic device coupled LiBr–H2O absorption heat pump system working at ambient temperature using Taguchi approach

The study attempts to optimise the parameters of a lithium bromide–water (LiBr–H₂O) miniature absorption refrigeration system using Taguchi approach for electronic cooling working at ambient conditions. Thermodynamic optimisation was performed to obtain the optimum coefficient of performance (COP) for heat removal of 100?W by using the Taguchi approach. Three factors were considered: generator temperature (T_g), condenser temperature (T_c) and absorber temperature (T_a), at three different levels. The result showed that the percentage contribution of generator temperature is more on COP. Optimisation of three significant heat exchangers: evaporator, condenser and absorber, was performed by using the Taguchi approach. The study was carried out individually for all the components by varying the hydraulic diameter and aspect ratio at three different levels. The results showed that the hydraulic diameter contributes more than the aspect ratio.     

Heat recovery and floating condensing in supermarkets

Supermarkets are great energy users in many countries. The potential for increased energy efficiency is large. One option is to utilize heat recovery (or heat reclaim) from condensers to heat the premises. Obviously this option is only interesting in relatively cold areas such as northern Europe, Canada, etc. An alternative to heat recovery is floating condensing pressure, which improves the coefficient of performance and decreases the energy consumption of the refrigeration system at lower outdoor temperature. Both heat recovery and floating condensing pressure can be utilized interchangeably depending on the heat requirements of the premises.A computer model that calculates the energy consumption in a supermarket with the possibility to simulate different system solutions for the refrigeration system has been developed at the Royal Institute of Technology, Department of Energy Technology. The software “CyberMart” is used in the present study to compare the potential of heat recovery and floating condensing in Swedish supermarkets. Measurements of different parameters such as temperatures, relative humidity and compressor power have been carried out in different supermarkets with heat recovery to validate the theoretical calculations.The present study shows that heating requirements can be covered completely by heat reclaim from the condenser. However, practical experiences show that installations are less efficient due to poor system solutions and/or control strategies. According to the results from CyberMart, the highest potential of energy saving is obtained from using a systems solution with both heat recovery and floating condensing.     

提高绝热吸收器压力的风冷技术分析

吸收器是吸收式制冷机的关键部分,传统吸收器基本采用水冷却。本文在传热传质分离技术的基础上,通过热力学理论分析,提出提高绝热吸收器压力的方法,建立了制冷系统仿真模型,并通过模型的求解,分析了提高绝热吸收器压力对实现吸收式风冷技术的有效性。研究结果表明,在溶液浓度不变甚至有所降低的情况下,提高绝热吸收器的压力,可显著提高风冷冷却器的传热温差,有效降低系统再循环倍率,且系统对外界空气温度敏感度较低,从而能很好地实现风冷技术。     

Comparisons of honeycomb sandwich and foam-filled cylindrical columns under axial crushing loads

For the conventional thin-walled energy absorber, the energy dissipation during a collision is concentrated in relatively narrow zones. This means that a great deal of material does not participate in the plastic deformation or enter the large plastic deformation stage. To expand the plastic deformation zones and improve the energy absorption efficiency, the authors presented a new type of honeycomb sandwich circular column. This innovative energy absorber is a composite structure composed of two circular aluminum tubes filled with core shaped as a large-cell honeycomb lattice. In this paper, six different honeycomb sandwich circular columns were investigated numerically. Comparisons of the interaction effect between tubes and filler, the deformation modes and the energy absorption abilities of these columns were conducted. The results were as following. The kagome sandwich column had the best energy absorption capability, followed by the columns sandwiched with triangle, hexagon lattices. In addition, foam-filled columns with different adhesive conditions were also simulated and compared with the honeycomb sandwich columns. It was found that increasing the adhesive strength improved the energy absorption and changed the deformation mode of the foam-filled columns. Furthermore, comparison showed that the honeycomb sandwich columns had higher specific energy absorption capability than the foam-filled tubes except for the strong bonded case. The kagome sandwich column performed best in crashworthiness, followed by triangle sandwich column.