空调系统变冷冻水温度调节节能研究

从风机盘管及表冷器换热的能量平衡角度出发,推导出影响盘管传热能力的数学关系式,得到影响换热的相关因素,并模拟出影响风机盘管和表冷器热工性能的影响规律,对变冷冻水温度调节对制冷能力、湿度控制等进行分析,为冷冻水系统的设计、控制与调节提供了依据.     

风机盘管的节能与智能化研究

通过对当前行业内卧式暗装风机盘管机组技术现状及存在的问题分析,提出改进创新的建议,其主要特点是:采用扁管换热器、无刷直流电机系统,分工况变转速控制及恒温智能控制等运行模式。通过对主要部件的合理整合及对运行情况的智能控制,降低机组运行能耗与运行噪声,解决传统风机盘管机组运行不节能,控制不灵活,智能化水平不足及舒适度不高等问题。     

空气-空气能量回收装置对风机盘管干工况运行节能效果的分析

在风机盘管加新风空调系统中,风机盘管干工况时只承担少部分室内瞬变负荷,由于干工况下新风机组需处理的新风焓差大,存在着干工况应用困难的问题.采用空气-空气能量回收装置(AAERE)预处理新风,可以解决风机盘管干工况运行中的困难.结果表明:采用AAERE回收部分余热预处理新风,可以降低新风机组需处理的焓差值,使用热回收后新风处理焓差值降低为33.6 kJ/kg,供冷量节约16.2%,使空调系统经济运行得到保障.     

静压与喷口对风机盘管性能影响研究

通过实验,在高风量下,不同静压与喷口情况下,对使用交流电机和直流无刷电机的风机盘管的性能进行研究。研究结果表明,选择不同的喷口对风机盘管的风量、供冷量与供热量均变化不大。在不同静压下,随着出口静压的提高,风机盘管风量、供冷量与供热量变小。     

提高风机盘管系统冷冻供水温度的节能评估

比较提高泠冻水供水温度的风机盘管系统与Active Chilled Bean系统(主动式冷梁系统)的节能效果。结合具体实例,通过计算分析,得出提高冷冻水供水温度可大幅提高风机盘管系统节能率,节能效果优于Active Chilled Beam系统。     

防SARS抗菌型干工况运行风机盘管空调系统设计理念

提出了干工况运行风机盘管加大焓差处理新风机组空调系统的设计理念 ,分析了其原理、空气处理方案和关键问题 ,对于当前针对SARS掀起的抗菌空调研发设计工作具有一定的指导意义     

对全空气定风量系统“可调新风比”的探讨与建议

<正>在公共建筑的空调设计中,常用的空调形式为全空气系统、风机盘管+新风系统、温湿度独立控制系统。无论采用哪种空调系统,都要根据建筑内的人员密度以及空调房间内的人数,确定空调房间的新风量。对于风机盘管+新风系统、温湿度独立控制系统,新风系统完全可以根据计算的新风量设计,相应的每层的新风机房、新风竖井、排风竖井、集中的新风热回收机组都按此新风量进行设计。那么对于全空气系统,又是如何规定的呢?1相关规范对伞空气定风培系统的可调新风比要求     

热湿地区直膨式辐射顶板空调系统模拟分析

以广州地区某办公楼为例,利用Energyplus对直膨式辐射顶板空调系统进行模拟,并与风机盘管+独立新风空调系统、双冷源新风机组+辐射顶板空调系统进行能耗对比分析。结果显示,在直膨式辐射顶板空调系统中,辐射顶板承担系统69.2%的显热负荷;相对于风机盘管+独立新风空调系统,系统节能率为20.09%,相对于双冷源新风机组+辐射顶板系统,系统节能率为7.16%。     

风机盘管特性参数在低温工况下简便算法的研究

针对低温地热采暖方式的特点，对低温地热采暖系统中采用的风机盘管结构及特性参数进行了改造与优化。分析了系统最佳运行参数及其影响因素；通过对不同型式风机盘管热工性能的试验及风机盘管设备的实验研究，总结出适用于低温地热采暖系统风机盘管总传热系数的简化计算公式，对工程设计具有一定的使用价值。     

焓差实验室能力提高的改造与实践

介绍了盘管风机焓差实验室的构造原理,对测试盘管风机供热量时发生的与实验条件不符合标准的情况进行数据分析,在相应分析的基础上找出修改方法,并在实践中检验效果,对保证风机盘管焓差实验室检测的准确以及提高实验室人员的水平具有一定的现实意义.     

Analysis of thermal performance of electromagnetic induction based molten salt heating system

将电磁感应加热技术应用到低谷电加热熔盐储热供暖领域,搭建熔盐电磁感应加热实验系统,以感应加热器为研究对象,探究熔盐以及线圈冷却水在不同熔盐流速和线圈电流工况下的温度变化规律,计算加热效率和冷却水热损失率。结果表明：电磁感应加热器可以快速加热熔盐,熔盐温升主要集中在开始加热80～240 s之间,温升速率在100 s时最大;改变线圈电流或熔盐流速,可以产生不同终温的熔盐,流速0.177 m/s时,熔盐在不同电流下出口温度分别为201.452 ℃、203.891 ℃、207.599 ℃、212.975 ℃和221.454 ℃;熔盐流速一定,熔盐和线圈冷却水吸热量随线圈电流的增加而升高;线圈电流不变,熔盐吸热量随流速的增加而升高、线圈冷却水吸热量随流速增加而降低;熔盐流速0.296 m/s、线圈电流600 A时,熔盐加热效率为69.28%,线圈冷却水热损失率为16.45%。     

Thermal comfort control on multi-room fan coil unit system using LEE-based fuzzy logic

Saving consumable energy and maintaining the thermal comfort level are two main topics in the heating, ventilating and air conditioning (HVAC) control field. The reliability of the controller is important as well. This paper proposes a least enthalpy estimator (LEE) that combines the definition of thermal comfort level and the theory of enthalpy into a load predicting way to provide timely suitable settings for a fan coil unit (FCU) fuzzy controller used in HVAC. According to the settings, including temperature and relative humidity, the fuzzy controller can make decisions and adjust the output of the FCU system. From actual experiments, the LEE-based FCU fuzzy controller can achieve the requirements of the FCU control system such as thermal comfort, energy efficiency and reliability.     

吸收式热泵技术在热电联产供热系统中的应用

介绍热电联产相结合的吸收式热泵供热技术,并结合实例工程的计算与分析,指出该技术在理论和实际应用中的可行性,该方法可回收利用大量冷却水的低温余热,大大增加现有热源的供热能力。     

Modelling and validation of a gas engine heat pump working with R410A for cooling applications

Gas engine heat pumps play an important role in energy saving and environment protection in both cooling and heating applications. In the present work, a thermal modelling of the gas engine driven heat pump in cooling mode is performed and system main parameters such as cooling capacity, gas engine energy consumption and primary energy ratio (PER) are computed. The modelling of the gas engine heat pump includes modelling of the scroll compressor, the plate evaporator and the gas engine. Discharged refrigerant mass flow rate and compressor power represent the main output parameters of the compressor semi-empirical model. Using the discharged refrigerant mass flow rates along with the available evaporation heat transfer correlations, the system cooling capacity is deduced. Based on the present experimental data, a correlation of gas engine energy consumption as function of compressor power, engine speed and ambient air temperature is obtained. Furthermore, the gas engine heat pump model is validated by comparing experimental and simulation data. The model error percentages to predict the cooling capacity, the gas engine energy consumption and the PER are 7%, 5%, 6% respectively.     

燃气中央空调在上海及周边地区的市场分析(一)

燃气中央空调的市场发展前景主要和以下四个因素有关:当地的气候条件,社会需求量,电力和燃气的供应条件,技术经济性。首先就前面两个问题作专题分析。上海和江浙地区的自然气候使得一年中需要采暖的时间和需要空调的时间几乎相等,这可充分发挥燃气直燃型冷热水机组作为中央空调的优势;上海和江浙地区房地产业的迅速发展为中央集中空调系统的发展提供了广阔的市场,预计每年能形成6.0×105 kW的市场容量。     

Cartesian graetz problems with air property variation

Heat transfer and wall friction results have been obtained numerically to demonstrate the effects of gas transport property variation on three classical, laminar flow situations: (a) heating and cooling at constant wall temperature with a fully developed velocity profile at entry, (b) heating and cooling at constant wall temperature with a uniform velocity profile at entry, and (c) heating with constant wall heat flux and a uniform velocity profile at the entrance.     

间接空冷系统空冷散热器运行特性的数值模拟

以某6×1000 MW间接空冷电厂主要建筑物和空冷塔平面布局为例,通过CFD模拟,得到了冷却空气流场、温度场,分析了机组热负荷、环境气温、风速、风向对空冷散热器进口空气流速的影响.结果表明:处于环境风上游的空冷散热器单元,其迎面风速最大,空气温度最低,冷却效果最好;而处于侧面的空冷散热器单元,迎面风速最小,空气温度最高,冷却效果最差.随机组热负荷增加,空冷散热器冷却空气流量增加,随环境气温、风速增加,空冷散热器冷却空气流量减小.风向的改变也会影响散热器的运行特性.     

Optimum selection (design) of thermoelectric modules for large capacity heat pump applications

Thermoelectric modules should be selected or designed to meet the specific cooling/heating requirements of a particular application and in most cases, the cooling/heating capacity and the working temperatures (hot and cold side temperature of thermoelectric devices) are known. Computer modelling can be used to assist the selection process by determining the relationships between the cooling/heating requirements and optimum thermoelectric parameters thermoelectric modules suited to large capacity thermoelectric heat pump applications. Copyright © 2004 John Wiley & Sons, Ltd.     

Heating,cooling and weather in Britain

Weather data giving annual temperature distributions, extremes, humidity, solar radiation, and temperature swings are presented, which may be used as a basis for estimating power requirements and running costs for proposed or existing heating and cooling systems. Conventional heating and cooling power calculations are summarized, with particular reference to anomalies and discrepancies. the need for further work on incidental gains, on the comfort tolerance zone, and on calculations of system capacity is highlighted.     

Experimental analysis of a domestic electric hot water storage tank. Part I: Static mode of operation

In this paper, the experimental analysis of the static mode of operation of a full-scale Domestic Electric Hot Water Storage Tank (DEHWST) with a capacity of 150 l is reported. The main purpose of the analysis is to determine the thermal behaviour of the DEHWST for the static heating and cooling periods in order to characterize its performance. The analysis is based on experimental data taken from a tank provided by the manufacturer and equipped with an appropriate data acquisition system. The storage tank, the data acquisition system and the experimental methodology are described. Performance parameters to evaluate the energy and exergy efficiencies and thermal stratification are defined and obtained from the experimental data. The results of the analysis for different heating powers and tank pressures are shown and discussed.