太阳能相变蓄能通风系统实验研究

针对太阳能通风的不稳定性和不可控性,提供一种利用太阳能作为热源,相变蓄热材料在日间进行蓄热,夜间利用储存热量热压通风的新型系统,使建筑物达到理想的通风效果.通过分别对相变温度为63℃、44℃的相变蓄热材料进行通风实验,得到不同相变温度下系统夜间通风量变化特性.结果表明,采用相变温度分别为63℃、44℃的相变蓄热材料棕榈...     

西安地区办公建筑夜间通风降温实验研究

以西安地区某栋办公建筑为例,通过实验测试,研究了蓄热体质量和蓄热体布置方式对夜间通风效果的影响,从房间室内温度波动和蓄冷量两个方面对夜间通风效果进行了评价。结果表明:在西安地区的夏季,当室外昼夜温差达到6℃以上时,对办公建筑进行夜间通风才有降温效果;蓄热体分散布置相比集中布置,可以增加40%~66%的蓄冷量,蓄热体的质量越小,分散布置的蓄冷优势越明显。     

夜间通风在浙江地区的适用性研究

本文基于夜间通风冷却潜力(CCP)评价方法,对浙江南、北气候分区各自的典型城市(温州、杭州)夜间通风的适用性进行定量分析。结果表明,浙江北区有一定的夜间通风冷却潜力,而浙江南区相对来说实施难度较大。探索并分析了浙江地区夜间通风的强化措施,介绍了相变蓄热在夏热冬冷地区夜间通风中的发展前景,总结了当前夜间通风运行技术方面的研究成果,为浙江地区工程实际夜间通风运用提供参考。     

东北严寒地区农村住宅被动式设计策略研究

在东北严寒地区,被动式设计是经济有效的节能设计策略。应用软件对东北严寒地区16个典型城镇进行了气象数据分析,针对东北严寒地区气候特点,将全年划分为采暖季和非采暖季,分别得出了窗户遮阳、建筑蓄热、建筑蓄热+夜间通风、直接蒸发冷却、间接蒸发冷却、自然通风、被动式太阳得热+低蓄热、被动式太阳得热+高蓄热、防止冷风渗透等9种被动式设计策略的有效性及综合有效性。研究表明,无论在采暖季还是非采暖季,被动式太阳得热都是最重要的被动式设计策略,得出的被动式设计有效性评价图表能够为建筑师进行被动式设计提供指导。     

夜间通风在不同气候条件下的适用性

近年来,夜间通风作为一种被动式降温手段受到越来越多的关注。为了研究夜间通风在中国不同气候条件下的节能效果,选取北京、上海、广州分别作为寒冷地区、夏热冬冷地区以及夏热冬暖地区的代表城市,使用建筑能耗模拟软件Energyplus建立一个办公建筑模型,分别在使用和未使用夜间通风的情况下计算出3个城市建筑在供冷季各月的供冷能耗和总能耗,通过对比,分析夜间通风的节能效果。研究结果表明,在相同的月份,夜间通风的效果会随着城市纬度的增加而增大,但对于整个供冷季,即便是在低纬度的夏热冬暖地区,夜间通风也具有显著的节能效果。     

利用供热水管进行夜间蓄热对供暖成本的影响

在既有的冷热源中心,有限的空间是应用夜间蓄热技术的主要阻碍。本文提出通过对水系统进行局部改造,将热水储存在水管内部,并研究分析了水管管径、保温性能和周围环境参数对夜间蓄热方法的经济性的影响效果。结果表明,水管管径越大,越适合作为夜间蓄热空间。夜间蓄热水管的管径较大时,无需增加管道保温性能,但管径较小时,应该加强管道保温,同时应尽量减少管道放置空间的通风换气量,以减小夜间蓄热的热损失。     

重庆某高校学生公寓夜间通风实验研究

针对7个室内布局基本相同的房间进行了夜间通风的实验研究,分析了不同天气状况、不同建筑朝向、不同阳台门开启度及不同控制方案条件下,夜间通风对学生公寓的降温效果。实验结果表明:阴天室内夜间温度降幅最大可达0.5℃,晴天降幅最大可达0.6℃;换气次数越大、通风时间越长,夜间通风的降温效果越明显;在夏季多阴雨天气的重庆地区,大力推广夜间通风降温技术,且使空调系统与夜间通风合理地联合运行,有利于实现建筑节能。     

湘西传统民居夏季热环境实测研究

本文以湘西传统民居的典型代表窨子屋为研究对象,通过对其进行夏季室内热环境实测并分析传统民居建筑热环境状况,研究结果表明:在室外温差较大的夏季,此类民居中厚重的蓄热墙体能够起到隔热降温的效果;高窄的天井白天主要为风压通风,在夜间则为热压通风,但在东侧房间中通风效果明显较差;采用架空通风地板和具有热缓冲层作用的楼层等措施,使得传统民居有着良好的气候适应性,对现代被动式绿色建筑设计具有一定启示。     

复合墙体建筑与太阳能的关系

传统建筑墙体的主要功能是承重和隔热保温。建筑物墙体综合设计应充分利用太阳能与建筑物地下的能源,尽可能使建筑物墙体具有蓄热、保温、传热和通风等功能,既美化整体建筑,又使整个建筑能耗降到最低,为人们提供更舒适的居住环境。     

建筑夜间通风降温研究进展

从夜间通风降温技术的原理入手,对其主要研究领域,包括气候潜力、降温影响因素分析、通风换气、对流换热、围护结构蓄热、夜间通风的建筑构造等进行了深入的文献研究,在此基础上归纳出了夜间通风的研究体系.对国内外的研究现状和存在问题进行了总结.     

Application of night cooling concept to social housing design in dry hot climate

A passive night cooling system was developed and implemented for a new project of social housing. The passive cooling system incorporates a solar chimney in combination with high thermal mass in the building construction. The natural ventilation is enhanced with the help of the solar chimney and night fresh air cools the building structure. The design of this concept was calculated by balancing energy using basic thermal equations for a summer reference day and evaluated using two simulation tools, TRNSYS and TAS. The building has been constructed and actually in process of monitoring.     

On the efficiency of night ventilation techniques applied to residential buildings

Climatic change and heat island effect in combination with the non-proper design of buildings have increased substantially the cooling load of buildings. Night ventilation appears to be one of the more promising passive cooling techniques. Many important theoretical and experimental studies have been performed however the existing information is presented in a segmented way. The present paper analyses energy data from two hundred fourteen air conditioned residential buildings using night ventilation techniques. The specific absolute energy contribution of night ventilation has been calculated. The relation of the cooling demand of the buildings with the specific contribution of night ventilation has been investigated. It is found that the higher the cooling demand of the building, the higher the potential contribution of night ventilation under specific boundary conditions. The role of air flow rate is investigated as well. It is found that the global utilisability of the energy stored during the night increases as a function of the air flow rate and the tilt of the regression line between the energy contribution and the air flow rate increases significantly with the air flow rate applied, although the energy contribution per unit of air flow is decreasing. The whole analysis contributes towards a better understanding and evaluation of the expected energy contribution of night cooling techniques.     

Simulation of wind-driven ventilative cooling systems for an apartment building in Beijing and Shanghai

This paper presents a performance evaluation of two passive cooling strategies, daytime ventilation and night cooling, for a generic, six-story suburban apartment building in Beijing and Shanghai. The investigation uses a coupled, transient simulation approach to model heat transfer and airflow in the apartments. Wind-driven ventilation is simulated using computational fluid dynamics (CFD). Occupant thermal comfort is accessed using Fanger’s comfort model. The results show that night cooling is superior to daytime ventilation. Night cooling may replace air-conditioning systems for a significant part of the cooling season in Beijing, but with a high condensation risk. For Shanghai, neither of the two passive cooling strategies can be considered successful.     

Thermal mass activation by hollow core slab coupled with night ventilation to reduce summer cooling loads

This study deal with the analysis of the effectiveness of free cooling ventilation strategies coupled with thermal mass activation to reduce peak cooling loads.A numerical simulation of the temperatures distribution of an office placed in Milan, Italy, during the month of July, is conducted on a Simulink^® dynamical model.No air-conditioned system is present but two different free cooling systems are analysed and compared. Both systems act a primary ventilation during the day and a night ventilation during the non-occupancy period but the first is a traditional mixing ventilation system, the other is a thermal mass activation system, i.e. the outdoor ventilation air, before entering the room, flows through the ducts of the hollow core concrete ceiling slab.The performances of the two systems are investigated by means of time profile analyses of indoor operative temperatures and by means of frequency temperature distributions during the occupancy period.The cooling performances are measured by two different discomfort indexes: one represents the discomfort time percentage during occupation period, the other the discomfort weighted on the distance of calculated operative temperature from the acceptable temperature interval.This paper, in last analysis, tries to highlight the possibilities on cooling loads reduction and on thermal comfort increase in Mediterranean climate, connected to new strategies for thermal mass activation and night ventilation.     

各气候区被动建筑节能技术适用性分析

被动式建筑节能,是通过利用自然气候资源的生态建筑设计原理,赋予建筑本身节能自然特性而实现的建筑节能,因而更为绿色环保,更有利于人类生存环境的可持续发展,成为建筑节能积极倡导的方向。针对中国各气候区典型城市的气候特点进行被动式太阳采暖、自然通风、蓄热墙体、诱导+夜间通风、直接蒸发冷却和间接蒸发冷度这六种被动式建筑节能技术适用性进行分析,并对各气候区的各种被动式建筑节能技术的适用性进行对比。     

Coupling of thermal mass and natural ventilation in buildings

The coupling of thermal mass and natural ventilation is important to passive building design. Thermal mass can be classified as external thermal mass and internal thermal mass. Due to great diurnal variation of ambient air temperature and solar radiation intensity, heat transfer through building envelopes, which is called external thermal mass, is a complex and unsteady process. Indoor furniture are internal thermal mass, affecting the indoor air temperature through the process of absorbing and releasing heat. In this paper, a heat balance model coupling the external and internal thermal mass, natural ventilation rate and indoor air temperature for naturally ventilated building is developed. In this model, the inner surface temperature of building envelopes is obtained based on the harmonic response method. The effect of external and internal thermal mass on indoor air temperature for six external walls is discussed of different configurations including lightweight and heavy structures with and without external/internal insulation. Based on this model, a simple tool is developed to estimate the indoor air temperature for certain external and internal thermal mass and to determine the internal thermal mass needed to maintain required indoor air temperature for certain external wall for naturally ventilated building.     

通风对疆北住宅热环境的影响分析

以乌鲁木齐市某典型住宅建筑为研究对象,采用Sketch Up建立建筑模型,并用Energy Plus模拟计算在不同通风模式下典型日的室内空气温度和辐射温度。表明充分利用夜间通风,可不同程度降低房间温度。其中,顶层房间夜间通风效果最好,较无通风模式日间室内空气温度约降低3.8℃,辐射温度约降低3.8℃,改善室内热环境效果显著。     

Impact of adaptive thermal comfort criteria on building energy use and cooling equipment size using a multi-objective optimization scheme

Recently adaptive thermal-comfort criteria have been introduced in the international indoor-climate standards to reduce the heating/cooling energy requirements. In 2008, the Finnish Society of Indoor Air Quality (FiSIAQ) developed the national adaptive thermal-comfort criteria of Finland. The current study evaluates the impact of the Finnish Criteria on energy performance in an office building. Two fully mechanically air-conditioned single offices are taken as representative zones. A simulation-based optimization scheme (a combination of IDA-ICE 4.0 and a multi-objective genetic-algorithm from MATLAB-2008a) is employed to determine the minimum primary energy use and the minimum room cooling-equipment size required for different thermal comfort levels. The applicability of implementing energy-saving measures such as night ventilation, night set-back temperature, day lighting as well as optimal building envelope and optimal HVAC settings are addressed by investigating 24 design variables. The results show that, on average, an additional 10 kWh/(m² a) primary energy demand and a larger 10 W/m² room cooling-equipment size are required to improve the thermal comfort from medium (S2) to high-quality (S1) class; higher thermal comfort levels limit the use of night ventilation and water radiator night-set back options. Compared with the ISO EN 7730-2005 standard, the Finnish criterion could slightly decrease the heating/cooling equipment size. However, it significantly increases both the heating and cooling energy demand; the results show 32.8% increase in the primary energy demand. It is concluded that the Finnish criterion-2008 is strict and does not allow for energy-efficient solutions in standard office buildings.     

Naturally ventilated and mixed-mode buildings—Part II: Optimal control

Natural ventilation and a combination of natural ventilation and fan-assisted cooling, in lieu of or as a supplement to air conditioning, offer significant reductions in building energy use in appropriate climates. In current practice, such buildings are operated with heuristic control strategies, involving the opening of windows under suitable indoor and outdoor conditions. Such methods are sub-optimal because they do not account for building thermal dynamics and predicted weather and therefore do not make decisions on the basis of estimated future conditions. This paper uses building thermal predictions from a data-driven thermal model to assess the impact of window and internal openings and fan operation. It then develops a means of ranking and choosing among a set of cooling strategies, with the objective of maintaining occupied-period temperatures within a specified range and minimizing fan energy use. The control algorithms were assessed with data from a test building.     

夜间通风技术应用与研究进展

文章根据国内外大量的文献资料对作为自然冷源的夜间风的降温节能潜力、通风效果影响因素及应用领域等进行了深入分析。基于已取得的夜间通风技术研究成果,指出应改善国内自然通风的研究方法,开展对过渡季节夜间通风的应用研究,同时应分析不同地区夜间通风适用性和夜间通风情况下室内热舒适性,以拓展夜间通风应用的领域。