公共建筑冷却塔台数调节节能运行分析

在空调系统非满负荷条件下,合理利用未启动制冷主机配套的冷却塔,降低制冷系统整体电耗,实现制冷主机与冷却塔综合电耗最低。利用麦克尔焓差理论公式建立机械通风冷却塔数学模型,分析不同空气湿球温度、风量、水量条件下冷却塔出水温度变化。分析结果表明:随着冷却塔气水比增加,冷却塔出水温度线性降低;随着湿球温度降低,气水比变化对冷却塔出水温度的影响变大。降低冷却水进口温度可以降低冷水机组电耗;增加冷却塔气水比导致冷却塔风机电耗增加。同时考虑冷水机组变工况特性及冷却塔变工况特性,分析得出:单台冷水机组配套运行其1.4～2.0倍额定冷却塔数量的条件下,冷水机组和冷却塔运行总电耗最低。同时,为冷水机组选择配套冷却塔时,建议选择2台机组对应4个单元冷却塔或3台机组对应6个单元冷却塔的配置方式,为后期节能运行预留条件。     

逆流密闭式冷却塔热力特性数值模拟

基于CFD软件和逆流密闭式冷却塔相关理论,对气流运动采用标准k-ε湍流模型,填料区、雨区和盘管区采用离散相模型计算,对填料区的膜状流动用滴状流动近似模拟。基于该模型,对设计制冷量为10 t/h的逆流密闭式冷却塔的气水流动与热质交换进行数值模拟。模拟分析了淋水密度和环境条件对冷却塔热力特性的影响,并分析得到了使冷却塔性能达到最优的无量纲参数气水比的取值。数值模拟结果表明:淋水密度和环境条件对逆流密闭式冷却塔的换热效果影响很大。     

深圳市某政府办公大楼空调冷却塔的节能诊断

为了实现中央空调系统的节能,对大楼的空调冷却塔运行性能进行了测试。通过对制冷机冷却水出口温度、冷却塔出口水温和室外气象参数的观察记录,由冷却塔效率计算公式求得冷却塔的效率。测试发现,该大楼冷却塔效率整体偏高,主要是因为风机功率偏大保证了较高的气水比。最后分析了对冷却塔效率的影响因素,提出了改造建议。     

塔式起重机钢丝绳附着系统设计

在热、核电厂冷却塔施工中，安装在冷却塔中部的塔机塔身多用钢丝绳替代刚性架与冷却塔壁附着，对这种附着系统的设计方法还在不断完善中。本文针对以往施工中遇到的问题，对一些重要参数提出新的计算方法，供设计、施工和安检人员参考。     

造纸厂电气间冷却塔供冷系统设计计算

过渡季、冬季可利用冷却塔供冷系统(利用冷却水的冷量为建筑供冷)为常年存在冷负荷的建筑(大型办公建筑内区、计算机房、电气间等)供冷。结合工程实例,对某造纸厂电气间冷却塔供冷系统进行设计计算。在对冷却塔流量进行设计计算时,应在保证过渡季、冬季冷却塔供冷系统较长的连续运行时间的基础上,选取合适的冷却塔进出水温差、流量比,最终确定冷却塔流量。     

双曲线冷却塔屈曲稳定计算相关规定及几个问题探讨

自然通风双曲线冷却塔的稳定性一直是其结构设计的重点关注的方面之一,其计算方法和计算手段的合理性与正确性直接关系到冷却塔的设计是否经济、安全、可靠。针对国内规范中对冷却塔稳定性的规定,本文阐述了目前在设计应用中遇到的若干问题,对相关的计算方法和建模方法进行了阐述,并结合实例说明这些问题,以及目前的解决办法。     

基于冷却塔辅助换热的地源热泵空调设计探讨

本文结合工程实例,探讨了采用冷却塔作为辅助换热设备的地源热泵空调系统设计方法,并从空调负荷计算、地源热泵主机选型,土壤换热系统设计,冷却塔选型以及冷却塔的运行策略等方面介绍了该地源热泵空调系统的设计思路,以期为以后的地源热泵空调系统设计提供参考。     

某酒店冷却塔供冷系统设计

介绍了冷却塔供冷系统在上海保利凯悦酒店及商业文化中心酒店项目中的应用,对冷却塔供冷系统的设计方法进行了总结,阐述了系统设计中冷冻水、冷却水供回水温度的确定、水泵匹配、冷却塔配置、系统节能计算等问题。     

干燥气候区的湿球温度及其对冷却水温度的影响

比较了我国标准对冷却塔设计用室外湿球温度的不同规定,并与ASHRAE手册进行了比较。分析了室外湿球温度对冷却塔出水温度的影响。从干燥气候区的实际工况出发,计算得到西北地区各典型城市及新疆20个县市的冷却塔出水温度。结果显示,新疆各县市冷却塔室外计算湿球温度为17~23℃时,冷却塔出水温度为26~30℃。指出了工程技术人员应注意的问题。     

干燥气候区的湿球温度及其对冷却水温度的影响北大核心

比较了我国标准对冷却塔设计用室外湿球温度的不同规定,并与ASHRAE手册进行了比较。分析了室外湿球温度对冷却塔出水温度的影响。从干燥气候区的实际工况出发,计算得到西北地区各典型城市及新疆20个县市的冷却塔出水温度。结果显示,新疆各县市冷却塔室外计算湿球温度为17~23℃时,冷却塔出水温度为26~30℃。指出了工程技术人员应注意的问题。     

户式中央空调在太原市场的发展及应用

介绍了小型户式中央空调的三种主要形式,分析了各自的特点并对三种主要类型的中央空调进行了综合比较,提出了户式中央空调在设计、施工及验收过程中存在的一些问题,经分析得出风冷冷热水机组为太原空调市场的推荐应用形式。     

Removal of organics from water in an aeration basin : A mathematical model

A mathematical model was developed to describe the removal of volatile organic compounds from drinking water in aeration basins. The model was used to simulate removal under a range of expected treatment conditions using the Continuous Systems Modeling Program. Results indicated that temperature and air-to-water ratio are the major factors influencing the removal of chloroform from water in an aeration basin. Bubble diameter was a lesser factor while liquid residence time had the smallest effect of the variables examined.     

Economic and exergy analysis of alternative plants for a zero carbon building complex

The feasibility of zero carbon emission plants for heating, air conditioning and domestic hot water (DHW) supply, is analyzed, with respect to conventional plants, for a new residential building complex to be constructed, in Northern Italy. Two zero carbon plants are considered: the first is composed of air-to-water heat pumps for space heating and cooling, PV solar collectors, air dehumidifiers, thermal solar collectors and a wood pellet boiler for DHW supply; in the second, the air-to-water heat pumps are replaced by ground-coupled heat pumps. The conventional plant is composed of a condensing gas boiler, single-apartment air to air heat pumps, and thermal solar collectors. The economic analysis shows that both zero carbon plants are feasible, and that the air-to air heat pumps yield a shorter payback time. The exergy analysis confirms the feasibility of both plants, and shows that the ground coupled heat pumps yield a higher exergy saving.     

砌筑砂浆配合比的探讨

对石砌体砌筑砂浆的配合比进行简单的探讨,指出石砌体砌筑砂浆灰水比大的原因及施工中对此应采取的态度。由于砌筑砂浆配合比设计在工程中的重要性,结合实际情况指出了砌筑砂浆配合比设计的工作方向。     

Towards developing skylight design tools for thermal and energy performance of atriums in cold climates

This paper presents an analysis of the impact of selected design alternatives on the thermal and energy performance of atriums based on the methodology outlined in the accompanying paper. Computer simulation programs were used to predict the impact of the selected design alternatives on the design performance outputs of atriums. Design alternatives focused on fenestration glazing types, fenestration surface area, skylight shape, atrium type, and interaction of the atrium with its adjacent spaces. Design performance outputs, evaluated with respect to a basecase design, included seasonal solar heat gain ratio, cooling and heating peak load ratios and annual cooling, heating and total energy ratios. Design tools were developed to quantify the impact of the design alternatives on the performance outputs. The design tools were cast into two-dimensional linear relationships with the glazing U-value and SHGC ratios as independent parameters. The results for enclosed atriums showed that the annual cooling energy ratio increased at a rate of 1.196 per unit of SHGC ratio and decreased at a rate of 0.382 per unit of U-value ratio. However, the annual heating energy ratio increased at a rate of 1.954 per unit of U-value ratio and decreased at a rate of 1.081 per unit of SHGC ratio. Similar trends were also found for the three-sided and linear atriums. Pyramidal/pitched skylights increased the solar heat gain ratio by up to 25% in the heating season compared to flat skylights. The effect of the skylight shape on the annual cooling and heating energy may be positive or negative, depending on the glazing U-value and SHGC ratios and the atrium type. Atriums open to their adjacent spaces reduced the annual cooling energy ratio by up to 76% compared to closed atrium spaces. However, open atrium spaces increased the annual heating energy ratio by up to 19%.     

双级耦合热泵系统在别墅中应用模拟预测分析

本文在分析了寒冷地区别墅区供热特点的基础上,提出了一种生态循环供暖的空气/水 户式水/水双级耦合热泵系统,对双级耦合热泵系统的运行可行性进行了预测分析后,针对其在我国北方寒冷地区代表城市运行状况进行了模拟分析,模拟结果表明本系统可以在寒冷地区别墅区的供热中应用。本文还进一步分析了双级耦合热泵的特点,并在系统上做出改进,提出了供别墅区使用的单、双级混合供热系统。     

Energy-saving with a gas engine-driven heat pump

Since May, 1978, a block of flats in Dortmund, Western Germany, has had heating and hot water supplied by an air-to-water heat pump driven by a gas engine. Capacity is 465 kW and the unit has been able to provided this service unaided by supplementary heating with external temperatures as low as — 12 °C. How the installation has performed in use, saving 50 per cent of primary energy compared with conventional methods, is explained here by technical officers of the Dortmund Public Works Department.     

结构转换层上下层间侧移角比取值探讨

由于受转换层上下刚度变化的影响,高层建筑结构在抗震设计时,采用侧移角比综合考虑抗剪刚度和抗弯刚度对层间侧移的影响更为合理。通过实例计算分析,给出了带托柱式转换梁的框架-核心筒结构的转换层上、下层间侧移角比的取值范围建议。     

结构转换层上下层间侧移角比取值探讨

由于受转换层上下刚度变化的影响,高层建筑结构在抗震设计时,采用侧移角比综合考虑抗剪刚度和抗弯刚度对层间侧移的影响更为合理。通过实例计算分析,给出了带托柱式转换梁的框架-核心筒结构的转换层上、下层间侧移角比的取值范围建议。     

基于BP神经网络的建筑结构隔震初步设计系统

基于BP人工神经网络,以建筑结构的抗震设防类别、设防烈度、场地类别、地震分组、高宽比、长宽比、刚度,质量和面积为主要影响因子,以隔震后结构的最大层剪力比和支座最大位移作为输出结果,建立一个隔震初步设计系统.经25个训练样本对该网络进行训练后,利用15个测试样本对网络进行了测试.通过测试结果与实际设计结果的对比,网络的平...