窗的传热系数对浙南住宅采暖空调能耗的影响

在三种不同空调运行模式下,利用建筑能耗模拟软件IES-VE对温州地区某住宅建筑能耗进行动态模拟,分析不同空调运行模式下,窗的传热系数对温州地区住宅建筑采暖空调能耗的影响规律。结果表明,窗的传热系数每减小20%,采暖能耗降低6%,且与空调模式相关性不大,但窗的传热系数对夏季空调能耗的影响与空调运行模式密切相关。连续空调模式下,窗的传热系数每降低20%,制冷能耗增加0.4%;间歇式空调模式下,制冷能耗随窗传热系数的增大而减小,窗的传热系数每降低20%,制冷能耗增加1.0%;间歇式空调＋自然通风模式下,窗的传热系数的每降低20%,制冷能耗减小0.5%。     

基于采暖空调能耗的武汉地区建筑南向窗口遮阳设计

武汉地区夏季太阳辐射强烈,对空调能耗有着重要影响。通过窗口外遮阳的设置可以调节太阳辐射,从而达到降低建筑能耗的目的。以武汉地区建筑为例,采用能耗模拟软件PKPM,分析了南向不同遮阳形式和尺寸的窗口外遮阳对建筑全年空调采暖能耗的影响。研究表明,南向窗口外遮阳对建筑空调采暖能耗有较大的影响,不同形式和尺寸的遮阳对建筑能耗影响差别较大。并得出武汉地区南向窗口采取综合遮阳制冷负荷最小的结论。     

浙南地区住宅建筑采暖空调能耗模拟分析

在3种不同空调系统运行模式下,利用建筑能耗模拟软件IES-VE对温州地区同一住宅建筑能耗进行动态模拟,分析空调运行模式对温州地区住宅建筑采暖空调能耗大小的影响。结果表明,空调运行模式由连续模式改变为间歇式,采暖能耗降低33.5%,制冷能耗减小53.2%,采暖空调总能耗降低43.5%,引入自然通风可将制冷能耗进一步降低27.6%,采暖空调总能耗降低50.5%。间歇式空调模式下,采暖空调能耗的降低与空调运行时间的减少并非线性关系。     

降低建筑空调能耗研究

在综合分析贵阳市地理气候的特点以及建筑空调工作原理的基础上，利用建筑行业专业DeST软件对建筑物室内外温度进行方针模拟，并将模拟结果进行分析汇总，最后提出了以下几条节能降耗措施和建议：首先，空调系统必须满足季节性温度调节需要，提供舒适的温度环境；夏季降温主要依靠自然通风的办法，在过度季节可有效降低建筑物的能耗水平；可以适当增大建筑物外墙的窗墙比，增加外围发射材料的使用比重，以显著提高建筑物的采暖能耗能力。本文的研究成果不仅为贵阳市建筑行业提供了可行性参考建议，还对其他气温接近地区的建设行业具有很强的指导意义。     

气候参数匮乏影响能耗分析

冬季采暖能耗和夏季空调制冷能耗是建筑能耗主要部分，另外还有照明、家电、设备能耗等．室外气象条件如何对建筑物的能耗影响很大．各气候区建筑节能设计标准就是在设定一定的气象条件制定的．各地气候是千变万化的，建筑物的传热过程也是一个动态的过程．建筑的得热或失热是随时随地随着室外气候条件的变化而变化的。     

夏热冬冷地区外窗传热系数对建筑能耗的影响

使用清华大学开发的建筑能耗模拟软件DeST h,对宁波地区一幢典型居住建筑的能耗随各向窗户传热系数的变化规律进行了模拟分析。分析表明：各向外窗传热系数变化对采暖能耗有较大影响,对空调能耗影响不大,通过降低传热系数的方法很难减少夏季空调负荷;南向窗户传热系数对建筑能耗的影响最大,北向次之,东、西向最小;南、北向外窗传热系数从4.7降到3.2节能投资性价比最高。并且分析了外窗传热系数降低引起空调能耗增加的原因。研究结果对夏热冬冷地区其他城市也具有参考意义。     

夏热冬冷地区居住建筑外遮阳设计探讨

夏热冬冷地区的居住建筑产生的建筑能耗主要为夏季空调能耗。对建筑外窗采取遮阳措施,夏季能降低空调能耗。从建筑节能角度看,采用外遮阳比采用内遮阳更能降低夏季空调能耗。针对夏热冬冷地区的地理位置和气候特点,结合建筑朝向,对居住建筑外遮阳设计进行了探讨。     

夏热冬暖地区既有建筑围护结构节能改造技术研究

夏热冬暖地区的气候特点是夏季漫长且高湿高热,冬季短暂温暖。夏热冬暖地区建筑主要能耗为夏季空调制冷,对其围护结构进行节能改造是本地区既有建筑节能改造的重要环节之一。根据夏热冬暖地区气候特点,结合相关建筑节能改造实例,提出针对本气候区域的既有建筑的外墙、外窗、屋面的节能改造相应的技术措施,包括增加保温层、采用隔热涂料、立体绿化等,并分析了各类技术的相应优缺点。同时,对一些改造实例的效果进行分析,提出适宜夏热冬暖地区既有建筑围护结构节能改造思路。     

新型变传热系数墙体浅析

目前我国能源形势紧张,建筑能耗占社会总能耗的一半左右,其中采暖空调能耗占建筑能耗的50%以上,采暖空调能耗中建筑围护结构的耗热量又高达30%以上。根据"十三五"规划的要求,降低建筑采暖空调能耗,可以着重从建筑围护结构方面入手,通过对墙体,门窗,屋顶等结构进行合理的设计,改善围护结构的热工特性,最大程度减少冬季采暖和夏季空调的负荷,控制室内的热湿环境,满足人们对室内舒适环境的要求。因此,课题组对国内外现有的改善围护结构热工性能的几种方法进行总结;基于部分严寒地区的昼夜温差大的气候特点,提出了新型变传热系数墙体,并采用数值模拟和实验对所提出的墙体进行了研究。研究所提出的新型变传热系数墙体为改善围护结构热工性能,减少建筑能耗提供一条新路径。     

庭院建筑形态参数与热工性能的相关性研究

庭院建筑是常见的建筑类型,其热工性能和有效利用与建筑几何形态关系密切。本文通过利用Designbuilder对上海地区125种不同形态特征的庭院建筑的模拟,分析了形态参数(建筑占地面积、层数、庭院面积比例)的变化对夏季制冷、冬季采暖以及全年空调能耗的影响,并以此建立了形态参数与建筑能耗的回归方程。研究发现:一定建筑面积时,为了有效降低庭院建筑的单位能耗,应首先选择降低建筑占地面积,并同时尽量减小庭院面积比例。此研究结果将有助于建筑师在方案创作时更好地掌握建筑节能设计的规律。     

夏热冬冷地区办公建筑降低供暖空调能耗的技术路径

以上海地区某办公建筑为例,基于EnergyPlus能耗模拟,探讨了围护结构性能提升和暖通空调系统优化这2条节能技术路径对夏热冬冷地区办公建筑降低供暖空调全年能耗的有效性.结果 表明:围护结构性能提升的节能潜力较小,经济性较差;单纯提高围护结构保温隔热性能并不能保证降低建筑年耗冷量,应综合分析全年供热供冷能耗确定围护结构...     

Evaluation of energy efficient design strategies for different climatic zones: Comparison of thermal performance of buildings in temperate-humid and hot-dry climate

Since the Kyoto protocol signed in December 1997 the majority of governments around the world have committed themselves to reducing the emission of the greenhouse gases. Thus, efficient use of energy and sustainability has become a key issue for the most energy policies. Sustainability and energy saving terms take place in building construction industry too since buildings are one of the most significant energy consumers. It is known that heating energy demand of a building has a great rate in building total energy consumption. In addition to that, the most of the heating energy has been lost from building envelope. TS 825, Heating Energy Conservation Standard for Buildings in Turkey, aims the reducing of heat loss in buildings through the envelope. But within buildings, one of the fastest growing sources of new energy demand is cooling and especially in hot-humid and hot-dry climatic parts of Turkey cooling season is much longer than the heating season. Moreover in hot-dry climate heat storage capacity of the envelope becomes more important issue than heat insulation for energy efficiency of the building. Since the Turkish standard is considering only heating energy conservation by using degree-day concept, Istanbul and Mardin are considered in the same zone, however those are in temperate-humid and hot-dry climatic zones, respectively. In this study energy efficient design strategies for these climatic zones have been explained and thermal performance of two buildings, which are constructed according to the TS 825 in Mardin and Istanbul cities were evaluated to show the importance of thermal mass in hot-dry climates.     

Climate change adaptation pathways for Australian residential buildings

Climate change can significantly impact on the total energy consumption and greenhouse gas (GHG) emissions of residential buildings. Therefore, climate adaptation should be properly considered in both building design and operation stages to reduce the impact. This paper identified the potential adaptation pathways for existing and new residential buildings, by enhancing their adaptive capacity to accommodate the impact and maintain total energy consumption and GHG emissions no more than the current level in the period of their service life. The feasibility of adaptations was demonstrated by building energy simulations using both representative existing and new housing in eight climate zones varying from cold, temperate to hot humid in Australia. It was found that, in heating dominated climates, a proper level of adaptive capacity of residential buildings could be achieved simply by improving the energy efficiency of building envelop. However, in cooling dominated regions, it could only be achieved by introducing additional measures, such as the use of high energy efficient (EE) appliances and the adoption of renewable energy. The initial costs to implement the adaptations were assessed, suggesting that it is more cost-effective to accommodate future climate change impacts for existing and new houses by improving building envelop energy efficiency in cooling dominated regions, but installing on-site solar PVs instead in heating and cooling balanced regions.     

Are the energy efficient rates (RVRs) approximate in different climatic locations for the same building with the same reform?

This paper studies the annual heating and cooling energy consumption and the variation law with the tools of characteristic temperature method (CTM) when making the same energy-saving measures on the same building under 43 different climate conditions. It can be found that for the same building, under different climate conditions, the maximal difference in annual energy consumption is up to more than 70 times and after improving building envelope, annual heating and cooling energy reductions are greatly different under various weather conditions, which illustrates that building energy consumption and its reduction is completely dependent on climate conditions; and the energy-saving potentiality and economic value with the same measures are quite different under various climatic conditions. Nevertheless, annual energy efficient rates of cooling are approximate (33.9–39.8%) for the same building with the same energy efficient measures in 43 climate conditions with quite different climatic conditions, and those of heating are also approximate (between 16.2% and 19.5%). This paper proves again the common rule that climate conditions determine energy consumption while energy efficient rates depend on the energy efficient measures.     

Application of latent heat thermal energy storage in buildings: State-of-the-art and outlook

Latent heat thermal energy storage (LHTES) is becoming more and more attractive for space heating and cooling of buildings. The application of LHTES in buildings has the following advantages: (1) the ability to narrow the gap between the peak and off-peak loads of electricity demand; (2) the ability to save operative fees by shifting the electrical consumption from peak periods to off-peak periods since the cost of electricity at night is 1/3–1/5 of that during the day; (3) the ability to utilize solar energy continuously, storing solar energy during the day, and releasing it at night, particularly for space heating in winter by reducing diurnal temperature fluctuation thus improving the degree of thermal comfort; (4) the ability to store the natural cooling by ventilation at night in summer and to release it to decrease the room temperature during the day, thus reducing the cooling load of air conditioning. This paper investigates previous work on thermal energy storage by incorporating phase change materials (PCMs) in the building envelope. The basic principle, candidate PCMs and their thermophysical properties, incorporation methods, thermal analyses of the use of PCMs in walls, floor, ceiling and window etc. and heat transfer enhancement are discussed. We show that with suitable PCMs and a suitable incorporation method with building material, LHTES can be economically efficient for heating and cooling buildings. However, several problems need to be tackled before LHTES can reliably and practically be applied. We conclude with some suggestions for future work.     

A parametric approach for performance optimization of residential building design in Beijing

During the early design stage of green residential buildings, there are tremendous potential of using parametric optimization to achieve preferable green performance, such as building energy consumption efficiency, daylighting, ventilation and thermal comfort. Taking residential design features into consideration, this paper presents an optimization workflow and effects based on a case study of a residential building project in Beijing. Firstly, 27 design parameters related to residential spatial form and building envelope were selected for the optimization. The simulation results of the cooling and heating load were taken as the optimization objects. Secondly, optimized schemes were obtained from 6246 simulation results, with 1925 verified simulation results proving that the optimized result is reliable. Finally, analysis was performed to establish the correlations between design parameters and performance in order to create the easy access for architects to determine design parameters depending on the performance sensitivity of each parameter. Analysis results showed that parametric optimization of spatial form and building envelope at the design stage is a feasible approach to reducing energy consumption in residential building design.

     

住宅建筑采暖空调能耗模拟方法的研究

住宅建筑的采暖空调能耗受室内居住人员行为方式的影响,在调查研究基础上,确定了两种反映室内居住人员行为方式的计算模式。在两种不同计算模式下,利用建筑热环境模拟工具DeST对上海地区同一住宅建筑能耗进行模拟,并将模拟结果与调研结果进行比较,分析计算模式对上海地区住宅建筑采暖空调能耗大小的影响,从而获得能正确反映上海地区住宅建筑采暖空调能耗大小的模拟计算方法。此方法可用于上海地区住宅建筑采暖空调的能耗分析与评价,并正确指导住宅建筑的节能设计。     

遮阳系数对供暖与空调能耗影响差异的逐时解析

以中国福州为例,从当地逐时气象数据入手,分析了建筑空调负荷及供暖负荷的所有时刻对应的逐时太阳辐射,用特征温度法研究当遮阳系数减小时各时刻建筑的空调与供暖能耗及相对变化(节能率)情况。研究发现,由于冬季有太阳辐射各时刻的供暖能耗相对于无太阳辐射各时刻能耗比例很小,故遮阳措施对供暖总能耗的影响不显著,从而证明DOE-2关于冬季遮阳系数减小对供暖能耗影响的结论值得商榷;由于夏季有太阳辐射各时刻空调能耗远大于无太阳辐射各时刻空调能耗,故遮阳措施对空调总能耗及节能率的影响非常显著,DOP2软件与特征温度法的结果是正确的;通过对福州全年各时刻空调供暖能耗、建筑负荷及节能率进行解析,揭示了看起来很分散的各时刻能耗及节能率差异数据总体上遵循的某种共性规律,供同行参考。     

Effect of external shading on household energy requirement for heating and cooling in Canada

Shading by neighbouring buildings and trees impacts the energy requirement of a building by reducing the amount of radiant energy absorbed and stored by its thermal mass. This study intends to quantify the magnitude of the effect of site shading on the energy requirement of residential buildings in Canada using a representative two-storey detached house. Site shading effects of neighbouring buildings and trees on annual heating and cooling energy requirements are evaluated using a building energy simulation program. The effects of the orientation, distance and size of the neighbouring object on heating and cooling energy requirement are investigated for four major cities (Halifax, Toronto, Calgary, Vancouver) representing the major climatic regions in Canada (Atlantic, Central, Prairies, Pacific). It is found that the annual heating and cooling energy requirement of a house in Canada may be affected by as much as 10% and 90%, respectively, by the existence as well as the orientation, size and distance of a neighbouring obstruction. Therefore, it is recommended that in building energy simulation studies, external shading should be given due consideration.     

Are the relative variation rates (RVRs) approximate in different cities with the same increase of shape coefficient?

The influence of the building's shape coefficient on annual heating and cooling energy consumption is significant, therefore, when laying down design standard for building efficiency, each country makes specific limitations to building shape coefficient. This paper takes two types of buildings with great difference of shape coefficient as the study objects and studies the influence rule of the same increase of shape coefficient on the annual cooling and heating energy consumption and its relative variation rates (RVRs) of the two buildings with the same envelope under 14 cities' climatic conditions in China, America and Europe respectively by DOE-2, DeST-h and CTM. It can be found that though the absolute increments of annual cooling and heating needs are obviously different in various cities with the same increase of shape coefficient, the annual relative variation rates (RVRs) of cooling and heating need are approximate in different cities.