南海意库3#办公楼温湿度独立控制空调系统运行实践研究

对应用于南海意库3#办公楼的温湿度独立控制空调系统进行了实际运行测试与实践,结果表明溶液除湿新风机组承担了室内全部潜热负荷以及人员的显热负荷,室内空气温度约为25～26℃、相对湿度约为50%～60%,且干式风机盘管在整个供冷季保持干工况运行.新风机组宜提前1.5～2 h开机对室内除湿,高温冷水机组宜提前1～1.5 h开机除去室内显热负荷.     

中央通风空调系统节能控制方案探讨（三）

本文系统地探讨了常规中央通风空调末端系统的节能控制方案,内容涉及室内温湿度参数的设定、新风机组加风机盘管系统、全空气变风量空调系统等节能控制技术。     

中央通风空调系统节能控制方案探讨（二）

本文系统地探讨了常规中央通风空调末端系统的节能控制方案,内容涉及室内温湿度参数的设定、新风机组加风机盘管系统、全空气变风量空调系统等节能控制技术。     

中央通风空调系统节能控制方案探讨（一）

本文系统地探讨了常规中央通风空调末端系统的节能控制方案,内容涉及室内温湿度参数的设定、新风机组加风机盘管系统、全空气变风量空调系统等节能控制技术。     

广州地区双冷源温湿分控空调系统冷源节能潜力分析

鉴于常规冷源空调系统采用冷凝除湿存在制冷效率低下、湿表面滋生细菌等问题,认为有必要进行温度和湿度的独立控制。介绍了双冷源温湿分控空调系统的基本原理和空气处理过程,比较了其与常规空调系统在设计方法上的差别。针对广州地区办公楼和宾馆建筑的负荷特性,分析了该空调系统的适用性。计算结果表明,在广州地区的办公楼和宾馆建筑中采用该空调系统有较大的节能潜力。     

辐射与对流耦合空调系统及其控制策略

介绍了一种辐射与对流耦合空调系统,该耦合系统采用基于双冷源的温湿度独立控制系统,适用于全天冷负荷波动较大的建筑。夜间室内的潜热负荷和显热负荷分别由独立新风和辐射顶板承担,白天室内冷负荷过大、辐射顶板的制冷量不足时,风机盘管开启,作为辅助制冷设备。该耦合系统既充分利用了辐射顶板舒适的特点,又采用风机盘管弥补了其换热量有限的缺点。给出了该耦合空调系统的控制方案,确立了4种工作模式。针对南京地区一典型住宅卧室建立了除湿模型,计算得到了该房间的预除湿时间。     

正能量建筑空调系统方案经济性及室内热舒适性分析

确定空调系统形式是建筑设计工作的重要环节。以正能量建筑为研究对象,通过设置风机盘管加独立新风空调系统和冷却顶板加置换通风空调系统两种空调系统方案,分别从经济性和室内舒适性进行分析。研究结果表明,无论是从经济性还是热舒适性角度考虑,与风机盘管加独立新风空调系统相比,冷却顶板加置换通风空调系统都更适用于正能量建筑。     

数码涡旋多联式空调系统节能性探讨

本文针多联式空调系统在实际运行时是否节能的问题,基于不同建筑面积的4个办公建筑模型,分析了数码涡旋多联式空调系统、定风量全空气系统和风机盘管加新风系统在实际运行时,室外工况、区域负荷和运行时间3个因素对其运行能耗的影响,并分析了能耗差异的原因.结果表明,与定风量全空气系统和风机盘管加新风系统相比,数码涡旋多联式空调系统在变工况时的调节特性最好;在变负荷工况下,是否存在定风量全空气系统或风机盘管加新风系统比数码涡旋多联式空调系统节能的空调开启率分界点及其分界点值的大小取决于建筑负荷与空调系统部分负荷性能之间的匹配;与定风量全空气系统相比,数码涡旋多联式空调系统的室内机个性化调节的特性使其在房间的空调运行时间参差时更为节能.     

独立新风加干式风机盘管空调系统用于高温高湿地区的适应性分析

独立新风加干式风机盘管空调系统(DCDVs)可以避免和改善常规空调系统在空气处理过程中存在的弊端。本文针对夏热冬暖地区的典型办公楼,首先将常规再热和非再热空调系统(CwRs和CwoRs)与DCDVs进行了模拟研究,比较了3种系统的主要设备冷量输出量和耗电峰值。而后,在不同负荷条件下,对室内空气温度与相对湿度状态进行了分析。最后,阐述了各系统年能耗及结露情况。模拟结果表明,DCDVs在全年空调运行中能保持较好的温湿度控制精度与稳定性,全年出现结露的时间低于全年空调运行时间的1%,且全年节能效果显著。     

温湿度独立控制空调系统应用数值模拟研究

通过Airpak软件对办公楼内干式风机盘管加新风系统的温湿度独立控制空调系统数值模拟与分析,可知温湿独立控制空调系统在夏季工况下需要优先控制室内空气的相对湿度,确保干式风机盘管能在干工况下运行,才能保证空调系统正常运行。室内空气的相对湿度可维持在52%~56%,温度可维持在24℃~26℃之间,且PMV值等于0,室内工作区域的人体热感觉在最舒适状态。     

A combined system of chilled ceiling,displacement ventilation and desiccant dehumidification

Different types of heating, ventilation, and air-conditioning (HVAC) systems consume different amounts of energy yet they deliver similar levels of acceptable indoor air quality (IAQ) and thermal comfort. It is desirable to provide buildings with an optimal HVAC system to create the best IAQ and thermal comfort with minimum energy consumption. In this paper, a combined system of chilled ceiling, displacement ventilation and desiccant dehumidification is designed and applied for space conditioning in a hot and humid climate. IAQ, thermal comfort, and energy saving potential of the combined system are estimated using a mathematical model of the system described in this paper. To confirm the feasibility of the combined system in a hot and humid climate, like China, and to evaluate the system performance, the mathematical model simulates an office building in Beijing and estimates IAQ, thermal comfort and energy consumption. We conclude that in comparison with a conventional all-air system the combined system saves 8.2% of total primary energy consumption in addition to achieving better IAQ and thermal comfort. Chilled ceiling, displacement ventilation and desiccant dehumidification respond consistently to cooling source demand and complement each other on indoor comfort and air quality. It is feasible to combine the three technologies for space conditioning of office building in a hot and humid climate.     

Influence of the ventilation system on thermal comfort of the chilled panel system in heating mode

In heating mode, fresh air is still essential for a chilled panel system in order to ensure the indoor air quality. In this paper, a chilled ceiling panel system was designed and built in a typical office room. The thermal environment and thermal comfort in the room were fully measured and evaluated by using the Fanger's PMV-PPD model and the standard of ISO 7730 respectively, when room was heated in two modes, one of which is the chilled panel heating mode and the other of which is the combined heating mode of chilled panel and supply air. The research results indicate that in the combined mode, ceiling ventilation improves the general thermal comfort and reduces the risk of local discomfort. Under the condition of same general thermal comfort, the heating supply upper limit of chilled panel can be increased by 12.3% because of air mixing effect caused by introduction of air ventilation.     

下送上回通风方式供冷与供暖运行性能比较

下送上回通风方式目前得到了广泛的研究应用,其供冷运行时就是置换通风,但同样一套通风系统在一些地区的寒冷季节则有可能需要作供暖运行.为了获得下送上回通风系统在分别作供冷与供暖运行时的具体性能参数,本文应用实验测试与计算流体力学(CFD)模拟的方法研究了置于环境实验室内的某办公环境.研究中分析比较了该办公环境内的空气速度、温度以及追踪气体污染物的浓度分布.研究结果表明,下送上回通风方式作供冷运行时空气温度及污染物浓度分层现象明显,空气处于半混合状态,置换效果较好;作供暖运行时,温度及污染物浓度趋于均匀,通风系统性能接近于混合送风系统,不具备良好的抑制交叉污染的能力.     

Displacement ventilation environments with chilled ceilings: thermal comfort design within the context of the BS EN ISO7730 versus adaptive debate

The current design standard BS EN ISO7730 [Moderate thermal environments—determination of the PMV and PPD indices and specification of the conditions for thermal comfort, International Standards Organisation (1995)] is based upon the work of Fanger, and essentially comprises a steady-state human heat balance model that leads to a prediction of the sensation of human thermal comfort for a given set of thermal conditions. The model was derived from laboratory-based measurements conducted in the mid-1960s in relatively ‘conventional’ environments. However, a chilled ceiling operated in combination with displacement ventilation represents a more sophisticated environment as compared with the original conditions in which the Fanger model was derived. This raised a question about the applicability of the current standard when designing for thermal comfort in offices equipped with chilled ceiling/displacement ventilation systems. This paper presents findings from an EPSRC-funded study that sought to answer the above question. Human test subjects (184 in total) carried out sedentary office-type work in a well-controlled environmental test room that simulated an office fitted with the above system. Measurements of environmental variables were taken at a number of locations near the subjects, each of whom wore a typical office clothing ensemble. The reported thermal comfort sensations were compared with values predicted from BS EN ISO7730 over a range of system operating conditions. It was shown that the current standard BS EN ISO7730 may be used, without modification, when designing for the thermal comfort of sedentary workers in offices equipped with chilled ceiling/displacement ventilation systems. These findings are interpreted within the context of a proposed modification to thermal comfort design standards that includes adaptive effects, and the influence of BS EN ISO7730 on the development of other radiant surface/displacement ventilation configurations is discussed.     

Chilled ceiling displacement ventilation design charts correlations to employ in optimized system operation for feasible load ranges

This paper expands Ghaddar et al. [N. Ghaddar, K. Ghali, R. Saadeh, A. Keblawi, Design charts for combined chilled ceiling displacement ventilation system (1438-RP), ASHRAE Transactions, 143 (2) (2008) 574-587] design charts of combined chilled ceiling (CC) displacement ventilation (DV) system to operating sensible load ranges from 40 W/m² to 100 W/m². It develops a global correlation of system load and operational parameters, with comfort measured by vertical temperature gradient and indoor air quality measured by the stratification height. The correlations are used for a known transient load profile in generating optimal settings of the CC/DV system operational parameters and associated energy consumption.An example is illustrated to show how the correlation could be used to size the system and to provide optimized control of the CC/DV system operation at low computational cost. Results of the current model are compared to the published case study of an optimized operation based on transient simulations of the space thermal model to achieve minimum operation cost [M. Mossolly, N. Ghaddar, K. Ghali, L. Jensen, Optimized operation of combined chilled ceiling displacement ventilation system using genetic algorithm, ASHRAE Transactions, 143 (2) (2008) 541-554]. The design correlations resulted in good agreement with published data (within 3% error in energy consumption and average 6% error in predictions of comfort and stratification height) at 1/4 of the computational time. The presented methodology provides an alternative for using the correlation for supervisory online controllers for the CC/DV system based on physically derived correlations.     

置换通风与冷却顶板系统热舒适性探讨

文中介绍了置换通风和冷却顶板相结合系统的基本原理及该系统对改善室内空气品质的作用,论述了各种参数对人体热舒适性的影响。     

顶板辐射供冷加置换通风系统广州地区适用性分析

顶板辐射供冷加置换通风系统以其独有的舒适性好、能耗低等特点逐步被国内用户接受,并在民用建筑项目中被采用.本文以等效辐射换热系数方法对盘管式辐射顶板单位面积的供冷量进行了数值模拟分析,并以广州地区为例,对该系统的适用性及影响因素进行了讨论:顶板辐射供冷加置换通风系统更适用于围护结构冷负荷指标低的节能建筑;当围护结构冷负荷指标低于20 W/m2时,采用较高供回水温度的冷水机组可满足室内设计要求且有明显的节能效果;顶板承担的冷负荷随人员密度的增大而减小,降低送风温度、采取大温差送风,可降低顶板承担的冷负荷.     

冷却顶板对置换通风系统的影响:CFD研究

以计算流体力(CFD)的模型为基础,采用有限容积法对带有冷却顶板的置换通风系统和不带冷却顶板的普通置换通风系统的温度场、气流分布及人体的热舒适性进行了模拟分析,模拟结果表明,冷却顶板-置换通风系统可以减小室内温度梯度,提高人体热舒适性。     

地板辐射与置换通风空调系统运行参数

建立了基于EnergyPlus的地板辐射供冷加置换通风空调系统模型,模拟得到的室内温度和辐射地板所承担冷量与实验结果的误差小于±7%。在此模型基础上,改变送风参数和供水参数,得到置换通风供冷量、辐射地板供冷量、地板表面温度、室内空气平均温度、AUST温度等参数的变化规律。结合热舒适性模型,得到满足室内热舒适性(-0.5≤PMV≤0.5)条件下,置换通风的送风参数和辐射地板的供水参数范围,为复合系统设计和应用提供依据。     

置换通风与冷却顶板

介绍了冷却顶板和置换通风的基本原理，以及两者在提高人体热舒适性和室内空气品质方面的优越性，并指出两者的结合使用可带来明显的节能效果。