严寒地区农村住宅围护结构保温改造分析

严寒地区多数农村住宅建筑围护结构热损失严重,造成其采暖能耗增加,强化建筑围护结构的保温性是提高建筑采暖效率的方式之一。以位于严寒地区的安达市某传统农宅为研究对象,采用EnergyPlus对该住宅围护结构的保温性能进行研究,并分析了建筑能耗情况,获得了建筑墙体、玻璃、屋顶等围护结构部位采用保温后的节能效率。研究结果表明：安达地区节能效率较好的墙体和屋顶保温材料为XPS保温板、玻璃窗结构形式为6mm+12mm+6mmLow-E低辐射玻璃;传统农宅采用建筑保温材料后,其节能率可达72.0%,从而降低了农村住宅采暖能耗,并可维持室内良好的热环境。     

不同气候区外窗对建筑能耗的影响分析

通过TRNSYS软件模拟不同传热系数的建筑外窗,在严寒地区和夏热冬暖地区,对建筑冷、热负荷的影响。分析得出,节能外窗在严寒地区夏季空调能耗的节能率为8.9%,冬季采暖能耗的节能率为39%,全年总建筑能耗的节能率为31%;在夏热冬暖地区夏季空调能耗的节能率为8.0%,冬季采暖能耗的节能率为22%,全年总建筑能耗的节能率为8.6%。由此可见,外窗在严寒地区的节能效果要明显优于夏热冬暖地区。因此,在新建建筑的节能设计和既有建筑的节能改造中,严寒地区应更加重视外窗部分。     

窗墙比与外窗类型对皖南办公建筑负荷影响分析——以安庆市某办公建筑为例

基于DeST-c软件,以皖南地区安庆市某办公建筑为研究对象,模拟研究建筑窗墙比与外窗类型对建筑负荷的影响。结合采光、美观和节能等因素,采用分配权重法得到皖南地区东西向窗墙比的设置应介于0.341～0.351之间为优;北向窗墙比的设置应当介于0.406～0.416之间为优;南向窗墙比的设置应当介于0.439～0.449之间为优。结合窗墙比分析结果,研究建筑模型装配不同类型节能门窗的建筑负荷。结果表明:对于皖南地区制冷能耗,玻璃种类影响显著,装配Low-e中空玻璃的铝合金、断桥铝合金、塑钢、集成木材外窗相比于装配普通中空玻璃,其空调节能率分别提高了44.14%、76.72%、78.22%、50.00%。而窗框系统的保温性则对于采暖能耗具有重要意义。建议皖南地区使用塑钢门窗装配Low-e中空玻璃的外窗系统,当以铝合金单玻外窗系统为基准时,其采暖节能率为26.08%,空调节能率为78.22%,全年累计总负荷节约了11.21%。     

建筑外窗热工性能对空调能耗与节能的影响分析

利用建筑环境模拟软件DeST-c,对广州某办公建筑外窗热工性能对空调能耗的影响进行了计算,计算结果表明减小外窗遮阳系数能显著降低空调能耗,当遮阳系数从0.9减小至0.2时空调耗冷量可降低26%;而外窗传热系数对空调能耗影响较小.并通过对全年逐时空调节能率进行分析,研究了遮阳系数影响空调能耗的机理,发现遮阳系数减小引起较...     

基于夏热冬冷气候冬季非空调工况的真空水流窗热性能测试

真空水流窗是一种新型透明围护结构技术,其应用能够降低建筑能耗.在成都市搭建试验测试平台,进行真空水流窗、中空水流窗和双层水流窗的对比试验,分析真空水流窗在冬季非空调工况下的热性能.结果表明,真空水流窗和中空水流窗对室内热环境均有良好的调节作用,双层水流窗调节能力略差.在强太阳辐射条件下,真空水流窗的太阳能集热能力显著高...     

内蒙古西部农牧区住宅冬季室内热环境优化研究

为提升内蒙古西部农牧区住宅的室内热环境、降低采暖能耗,选取具有代表性的生土住宅、砖混住宅和被动式住宅进行调研,并对室内外的空气温度、相对湿度等参数做的测试。通过分析数据得出,被动式住宅的室内热环境优于砖混住宅也优于生土住宅。对影响能耗的住宅朝向、南向窗墙比、北向窗墙比、透明围护结构材质、保温层厚度、非透明围护结构材质、附加阳光间进深、东向窗墙比等8个因素进行单因素优化和正交优化,计算出优选方案。研究结果可为内蒙古西部农牧区住宅冬季室内热环境的改善提供依据。     

武汉地区超低能耗办公建筑窗墙比优化设计研究

外窗是建筑联系室内外的重要节点,在营造良好室内光环境减少照明能耗的同时带来太阳辐射得热。以武汉地区某办公建筑为例,应用eQuest和Dali2020软件进行能耗及自然采光模拟,结合超低能耗建筑以最少的能源消耗提供舒适室内环境的要求,研究不同窗墙比工况下,供暖空调能耗、照明能耗及自然采光效果的变化趋势。分析得出在满足基本采光需求条件下的最佳窗墙比为0.25,进一步改善采光质量条件下的窗墙比,建议取值0.35～0.40,为武汉地区建筑窗墙比的优化设计提供借鉴及参考。     

外墙构造和窗墙比对变频空调房问采暖能耗及PMV的影响

采用SCIENCE软件对南京地区冬季某日一变频空调房间的热环境进行数值模拟,得出了采暖能耗和PMV随外墙构造和窗墙比的变化规律,并通过室内加热量和平均PMV对其进行分析.研究表明:墙体传热系数越低,越节能,随传热系数的逐步减小,节能增加效果减弱;综合考虑南京地区外墙宜选用保温墙24;能耗随窗墙比增大以指数增加,窗墙比每增加10%,能耗增加0.24%～2.74%;围护结构中外墙和窗户对能耗的影响较大,比重分别为50.4%和34.9%;外墙构造对室内热舒适性的影响不大,但窗墙比影响较大,窗墙比越大,平均PMV值波动越厉害,热舒适性越差.     

内蒙古西部地区居住建筑围护结构正交优化分析

随着内蒙古地区社会经济的快速发展,建筑能耗问题越来越突出。为解决这个问题,以内蒙古西部居民建筑为例,建立典型模型。利用能耗模拟软件DeST-h计算窗户材质、南向窗墙比、北向窗墙比、外墙保温层厚度和屋面保温层厚度对冬季采暖能耗的影响,通过正交实验得出优化方案,认为内蒙古西部居住建筑应该增加保温层厚度,选择保温性能好的窗户。     

外墙构造和窗墙比对变频空调房间采暖能耗及PMV的影响

采用SCIENCE软件对南京地区冬季某日一变频空调房间的热环境进行数值模拟,得出了采暖能耗和PMV随外墙构造和窗墙比的变化规律,并通过室内加热量和平均PMV对其进行分析。研究表明：墙体传热系数越低,越节能,随传热系数的逐步减小,节能增加效果减弱;综合考虑南京地区外墙宜选用保温墙24;能耗随窗墙比增大以指数增加,窗墙比每增加10%,能耗增加0.24%～2.74%;围护结构中外墙和窗户对能耗的影响较大,比重分别为50.4%和34.9%;外墙构造对室内热舒适性的影响不大,但窗墙比影响较大,窗墙比越大,平均PMV值波动越厉害,热舒适性越差。     

综合建筑空调节能技术

介绍了建筑空调节能的综合性技术,包括建筑外观特征与围护结构的节能技术(建筑朝向、布局、围护结构保温隔热、气密性、窗墙比)、建筑空调设备的节能运行技术(蓄能空调、热回收、变频技术)和建筑空调能源利用的节能技术(水源热泵、地源热泵、免费供冷、太阳能)。强调了建筑节能的社会效益和环境效益。     

某节能住宅小区地下水源热泵系统应用的经济性及节能性分析

针对咸阳市某节能住宅小区供冷供热的需求,依据建筑节能规范指标要求,进行围护结构热工设计与计算。结合当地丰富的浅层地下水资源条件,确定了利用地下水源热泵系统对该住宅小区进行供冷供热方案。对系统经济性和节能性进行计算与分析,对比分析了建筑围护结构和空调系统对建筑节能的贡献率,指出了建筑节能集成效益的优势。     

不同地区住宅能耗与太阳能吸收式空调系统匹配性分析与模拟研究

为了满足农村住宅清洁用能的需求,多种形式的能源系统逐渐开始应用于广大的农村地区。随着太阳能集热器集热效率的提高,热驱动机组各项性能不断改善,这样有利于太阳能吸收式空调系统在农村地区的应用。为了研究太阳能吸收式空调系统与农村住宅全年能耗的匹配问题,文章首先建立了DeST住宅模型,然后利用TRNSYS软件建立了太阳能吸收式空调系统模型,最后根据模拟结果对国内不同气候区内农村住宅供热季、供冷季的平均热负荷值,以及全年的能耗进行分析。此外,文章还分析了典型日太阳能吸收式空调系统的运行策略与效果。分析结果表明:在无辅助热源的条件下,太阳能集热器的集热温度会大于80℃,满足空调机组的热驱动温度,因此可以作为太阳能吸收式空调系统的的热源;当启动温度为85℃时,空调机组的制冷量可以达到8 kW,性能系数COP为0.733。     

A global survey of adverse energetic effects of increased wall insulation in office buildings: degree day and climate zone indicators

The energy efficiency of a building depends to a large measure on the characteristics of its envelope insulation. In the special case of internal gain dominated buildings, excessive building insulation may prevent the heat loss through the walls (anti-insulation effect), and thus generate the need for energy-intensive active systems to remove this thermal load. Detailed energetic simulations of a typical office building in Malaga (Spain), Dubai (UAE), and El Dorado (USA) show this anti-insulation effect and its dependency on climatic, constructive, and use factors. Results indicate that buildings in a predominantly cooling environment but within a certain range of heating degree days (HDD) will display this behavior: with very few to no HDD, the building’s energy consumption becomes insensitive to insulation increase (Dubai case); with a low number of HDDs the building becomes sensitive to anti-insulation (Malaga), and once a threshold is passed (El Dorado), the building’s energy consumption decreases with increased insulation. In order to further explore these limitations, simulations in 132 global locations of the building response to a step change in insulation are carried out. Results indicate that buildings in the Köppen climate zones Csa and Csb (Mediterranean climate), in locations with less than 2000 HDD and between 2000 and 5000 cooling degree days (CDD) are most susceptible to this anti-insulation behavior; however, quantitatively, the efficiency loss in these areas due to the insulation increase does not exceed 1 % of the overall energy consumption for the particular building studied and thus remains of limited importance.     

封闭阳台温差修正系数取值及其对供暖设计的影响

封闭式阳台作为居住建筑延伸空间,是被动式附加阳光间的一种形式.该文通过分析封闭阳台型式、围护结构热工性能、太阳辐射强度、外遮阳等因素对阳台温差修正系数α的影响,推荐给出严寒、寒冷、夏热冬冷地区代表城市居住建筑不同型式封闭阳台适用于工程应用的温差修正系数简便计算公式,为准确评估封闭阳台这类附加阳光间对供暖房间增益效果提供...     

Evaluation on energy and thermal performance for residential envelopes in hot summer and cold winter zone of China

As a result of rapid economic growth in the last several decades, energy issue is becoming more and more important in today’s world because of a possible energy shortage in the future; the usage of residential electricity has increased rapidly in China and building energy efficiency is included as one of the 10 key programs targeting energy efficiency improvement in the 11th Five-Year Plan. In response to the growing concerns about energy conservation in residential buildings and its implications for the environment, systematic evaluation on energy and thermal Performance for residential envelops (EETP) is put forward to assess the energy efficiency of envelop designs and to calculate the energy consumption of cooling and heating systems. Hot summer and cold winter zone of China was selected for EETP analysis because of its rigorous climatic and huge energy consumption. The correlations between EETPs and electricity consumptions in cooling season, heating season, and the whole year were built in Shanghai, Changsha, Shaoguan and Chengdu, which represent A, B, C and D subzone of hot summer and cold winter zone in China, respectively. Illustrations indicate that the algorithm is simple and effective, energy and thermal performance of residential envelopes can be evaluated easily. The maximum allowable values of EETPs were determined when just meeting the compulsory indices of Standard JGJ134-2001, the corresponding allowable EETPs were also gained when achieving different energy-saving degrees on basis of it. EETP method can suggest possible ways to improve the energy efficiency for envelope designs of new building and retrofits of existing buildings and provide governments some useful information for the establishment of new policy on energy efficiency buildings. It has important meanings to carry out sustainable residential building designs with high thermal comfort and low energy consumption.     

Solar heat gains through train windows: a non-negligible contribution to the energy balance

The sector of transportation accounts for about one third of the total energy consumption in Switzerland. A monitoring campaign of the energy consumption of a regional train revealed the critical energy-consuming systems. Heating, cooling and ventilation were identified as major consumers. Windows are a source of non-controlled heat transfer. In summer, it may result in overheating leading to larger cooling loads while in winter, it is an important source of thermal losses. Selective double glazing and solar protection coatings can reduce these effects. Angular-dependent optical properties of a selective double glazing have been measured, and the solar heat gain coefficient (g value) was determined. An estimation of the solar gains received by a panoramic waggon was performed using the monitored solar irradiation and the measured properties of the glazing. These data were compared to the heating and cooling energy consumption monitored in this waggon. Solar gains were found to be in the same order of magnitude that the heating energy during some sunny days. They were also compared to the estimated thermal losses through the glazing and the entire envelope. These results show that the solar gains play a non-negligible role in the energy balance of the waggon. Furthermore, thermal simulations were performed to evaluate the solar gains in different conditions. It showed that 7 to 13% of energy can be saved using the glazing adapted to the climatic conditions. In addition, improving the thermal insulation of the train envelope or equipping the train with an efficient heat recovery system can lead to significant energy savings.     

Path Analysis of Energy-Saving Technology in Yangtze River Basin Based on Multi-Objective and Multi-Parameter Optimisation

The Yangtze River Basin in China is characterised by hot-and cold-humid climates in summer and winter, respectively. Thus, increased demand for heating and cooling energy according to the season, as well as poor indoor thermal comfort, are inevitable. To overcome this problem, this study focused on the influence of passive design and heating, ventilation, and air conditioning equipment performance on the energy performance of residential buildings, and explored potential energy-saving technology paths involving passive design and improved coefficient of performance through a multi-objective and multi-parameter optimisation technique. A large-scale questionnaire survey covering a typical city was first conducted to identify family lifestyle patterns regarding time spent at home, family type, air conditioner use habits, indoor thermal comfort, etc. Then, the actual heating and cooling energy consumption and information of model building were determined for this region. Subsequently, the design parameters of an individual building were simulated using Energyplus to investigate the cooling and heating energy consumption for a typical residential building with an air conditioner. The results indicated an improvement of approximately 30% in energy efficiency through optimisation of the external-wall insulation thickness and the external-window and shading performance, and through use of appropriate ventilation technology. Thus, a multi-objective and multi-parameter optimisation model was developed to achieve comprehensive optimisation of several design parameters. Experimental results showed that comprehensive optimisation could not only reduce cooling and heating energy consumption, but also improve the thermal comfort level achieved with a non-artificial cooling and heating source. Finally, three energy-saving technology paths were formulated to achieve a balance between indoor thermal comfort improvement and the target energy efficiency(20 kWh/(m2?a)). The findings of this study have implications for the future design of buildings in the Yangtze River Basin, and for modification of existing buildings for improved energy efficiency.     

Calculation of Escaped Solar Energy in Glazing Façade Buildings

ABSTRACT

In building's cooling load calculation, solar heat gain through transparent envelope is calculated by using solar heat gain coefficient which is a thermal performance parameter of window. In traditional buildings, window-wall ratio is small so it's is assumed that the incoming solar radiation can't escape through the window again. But this hypothesis isn't suitable for glazing façade buildings. To calculate the escaped solar energy ratio, a solar radiation model is established on the basis of radiosity-irradiation method and calculated by using the commercial software of Matlab. The impact of time, room geometric dimensioning and absorptance of interior surfaces are evaluated. The numerical calculation results show that the escaped solar radiation ratio varies according to solar radiation incident angle in different times and its maximum value is 8.85% in summer solstice; compare to the width, the depth and height of the room affect the ratio significantly; the reflectance of the floor has greater impact on the escaped solar energy ratio than of other internal surfaces. Finally a fitting formula of escaped solar energy ratio is provided as a function of the ratio between the window area and the internal surface area and of the internal surfaces' absorptance.