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%。     

南京地区窗户的传热系数和窗墙比对住宅能耗的影响

使用清华大学研发的建筑能耗模拟软件DeST,对南京地区某典型住宅进行动态能耗模拟,分析了不同窗户传热系数和窗墙比对住宅能耗的影响规律,得出南京地区住宅类建筑节能中的一些注意点。     

温和地区窗墙比对居住建筑能耗影响分析

本文主要研究温和地区居住建筑合理的窗墙比。以昆明某居住建筑为研究对象,基于模拟软件DeST-h对建筑全年能耗进行动态模拟,研究居住建筑照明负荷和冷热负荷在不同朝向不同窗墙比时的变化规律。结果表明温和地区居住建筑南向窗墙比宜为0.5,北向窗墙比宜为0.4,东向窗墙比宜为0.5,西向窗墙比宜为0.3。采用上述窗墙比设置,有利于降低建筑能耗,对工程设计有参考价值。     

窗墙面积比对建筑能耗的影响

在影响建筑能耗的因素中,因外窗的绝热性能最差,从而成为影响室内热环境质量和建筑能耗的主要因素之一.为实现建筑节能的目的,需要对窗墙比进行优化.本文利用清华大学开发的DeST(Designer's Simulation Toolkits)软件对西安地区一办公楼在不同窗墙面积比下的能耗做了模拟计算分析,总结出了西安地区建筑能耗随窗墙面积比的变化规律,并在此基础上给出了西安地区此类建筑的最佳窗墙面积比.     

窗墙比和体形系数对办公建筑能耗的影响

济南地区某公共办公建筑,其围护结构按照高效节能的设计方法进行设计。运用Dest软件对该建筑进行能耗模拟,模拟该建筑的逐时能耗,分析不同体形系数和窗墙比对建筑物能耗的影响,以及两者共同作用下的影响。通过模拟结果得出:窗墙比对夏季负荷的影响要大于对冬季的影响,冬季窗墙比越大,能耗变化率相对较小;而体形系数的不同对建筑物空调能耗的影响变化较小。     

建筑形状比对办公建筑冷(热)负荷的影响分析

基于DeST软件,利用正交试验法对办公建筑室内的冷负荷影响因素进行了分析,得出室内冷(热)负荷随着形状比变化的曲线,并应用曲线分析负荷变化趋势,找出冷(热)负荷随着形状比变化的具体关系式,可依此确定最佳建筑节能形式的方案。     

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。     

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.     

建筑外窗对采暖热负荷的影响分析

以天津市某三层办公楼一层办公室南向外窗为研究对象,通过计算整个采暖季南向外窗的逐时累计得热量及失热量,分析不同类型窗对于整个采暖季累积采暖热负荷的影响.     

Vary-therm wall for cooling/heating of buildings in composite climate

A modified form of Trombe Wall in which the glazing has been replaced by weather resistance material has been proposed and examined for winter heating and summer cooling in mixed climate conditions characterized by a mild winter and a relatively harsh dry summer. The experimental results indicate the potential applications of such a wall, known as Vary-Therm Wall, in solar passive building architecture for mixed climatic conditions.     

System performance and economic analysis of solar-assisted cooling/heating system

The long-term system simulation and economic analysis of solar-assisted cooling/heating system (SACH-2) was carried out in order to find an economical design. The solar heat driven ejector cooling system (ECS) is used to provide part of the cooling load to reduce the energy consumption of the air conditioner installed as the base-load cooler. A standard SACH-2 system for cooling load 3.5 kW (1 RT) and daily cooling time 10 h is used for case study. The cooling performance is assumed only in summer seasons from May to October. In winter season from November to April, only heat is supplied. Two installation locations (Taipei and Tainan) were examined.It was found from the cooling performance simulation that in order to save 50% energy of the air conditioner, the required solar collector area is 40 m² in Taipei and 31 m² in Tainan, for COP_j = 0.2. If the solar collector area is designed as 20 m², the solar ejector cooling system will supply about 17–26% cooling load in Taipei in summer season and about 21–27% cooling load in Tainan. Simulation for long-term performance including cooling in summer (May–October) and hot water supply in winter (November–April) was carried out to determine the monthly-average energy savings. The corresponding daily hot water supply (with 40 °C temperature rise of water) for 20 m² solar collector area is 616–858 L/day in Tainan and 304–533 L/day in Taipei.The economic analysis shows that the payback time of SACH-2 decreases with increasing cooling capacity. The payback time is 4.8 years in Tainan and 6.2 years in Taipei when the cooling capacity >10 RT. If the ECS is treated as an additional device used as a protective equipment to avoid overheating of solar collectors and to convert the excess solar heat in summer into cooling to reduce the energy consumption of air conditioner, the payback time is less than 3 years for cooling capacity larger than 3 RT.     

汽油醇发动机点火时刻及空燃比对输出扭矩影响的仿真分析

采用汽油醇后的汽油发动机的最佳点火时刻及最佳空燃比将发生变化,为合理地分析汽油醇发动机点火时刻及空燃比对发动机输出扭矩的影响,首先,通过构建汽油醇发动机数学模型,利用Matlab/Simulink设计汽油醇发动机仿真系统,并通过仿真系统分析汽油醇发动机点火提前角分别为13°,14°,16°时及空燃比A/F分别为14.5,14.7,14.8时对发动机输出扭矩的影响。经过对不同曲线的对比分析,得到了汽油醇发动机最佳点火提前角为16°,最佳A/F为14.5。所设计的汽油醇发动机仿真系统能真实地反映出汽油醇发动机的工作情况,对于分析汽油醇发动机的性能有较大的帮助。     

Experimental investigation and simulation analysis of the thermal performance of a balcony wall integrated solar water heating unit

A balcony wall type solar water heater system was designed and constructed in a high-rise building. The U-type evacuated glass tube solar collector is fixed vertically on the balcony wall. The water, heated in the solar collector, flows through the exchanger coil in the water tank and then flows back to the solar collector. With regard to the hot water supply system, the cold water, heated by the heat exchanger, is sent to the point of use. Considering storeys and water consumption pattern, four apartments are selected for testing. Meanwhile, the theoretical analysis with TRNSYS was presented. According to the experimental results, mean daily collector efficiency is about 40%. Solar fraction is high in summer and autumn for the relative high radiation and high ambient temperature. Under given conditions, the annual energy extracted from tank is 2805.3 MJ/m², and the annual solar fraction is 40.5%. When the tank volume-to-collector area ratio is decreased to 37.5 L/m², the solar fraction can be increased to 50%. The results show that the family to use water all day round gets higher solar fraction than the family using hot water mostly in the morning and night.     

Influence of a building’s integrated-photovoltaics on heating and cooling loads

Building integrated photovoltaics (BIPV) has the potential to become a major source of renewable energy in the urban environment. BIPV has significant influence on the heat transfer through the building envelope because of the change of the thermal resistance by adding or replacing the building elements. Four different roofs are used to assess the impacts of BIPV on the building’s heating-and-cooling loads; namely ventilated air-gap BIPV, non-ventilated (closed) air-gap BIPV, closeroof mounted BIPV, and the conventional roof with no PV and no air gap. One-dimensional transient models of four cases are derived to evaluate the PV performances and building cooling-and-heating loads across the different roofs in order to select the appropriate PV building integration method in Tianjin, China. The simulation results show that the PV roof with ventilated air-gap is suitable for the application in summer because this integration leads to the low cooling load and high PV conversion efficiency. The PV roof with ventilation air-gap has a high time lag and small decrement factor in comparison with other three roofs and has the same heat gain as the cool roof of absorptance 0.4. In winter, BIPV of non-ventilated air gap is more appropriate due to the combination of the low heating-load through the PV roof and high PV electrical output.