Classified identifications: the annual relative variation rates (RVRs) of energy consumption are approximate in different cities with the same shading coefficient

By research on the variation laws of annual heating and cooling energy consumption and their RVRs with sun-shading coefficient in all the hours with and without solar radiation in three cities (Tampa, Sterling of USA and Fuzhou of China) respectively, we can find that: in winter, the proportion of the heating energy consumption in all the hours with solar radiation in the annual heating needs is very small (less than 15%), the influence of shading measures on the annual total heating energy consumption and its RVRs is not so significant. And thus the predictions of DOE-2 on the effect of shading measures on the annual heating energy consumption deserve further study. However, in summer, the proportion of the cooling needs of each hour with solar radiation in the annual total cooling needs is very large (more than 95%), therefore the influence of shading measures on the annual cooling energy consumption and its RVRs is very great. And hence the predictions of DOE-2 and CTM are both reasonable. By comparative analysis on two representative cities, we can find out that under the same sun-shading coefficient, the annual heating RVRs and the annual cooling RVRs are both approximate in different cities. By further analysis on the distributions of the daily heating and cooling RVRs, the monthly heating and cooling energy consumption and its RVRs in Sterling with different shading measures, we can find out that sun-shading coefficient has a far less impact on the annual heating energy consumption than on the annual cooling needs.     

Identifications: the relative variation rates (RVRs) of cooling and heating are approximately the same in different cities with the same increase of shape coefficients

Among 14 background cities, Boulder of America and Shanghai of China which differ in climatic conditions are selected for comparison. Taking the building with traditional envelope when the ventilation rate is 0 as an example, this paper studies the variation laws of hourly, daily and monthly relative variation rates (RVRs) with the same increase of shape coefficient in the two cities. By comparisons, we find that though there exists significant difference in annual heating and cooling hours, days and months between Boulder and Shanghai, the distribution laws of hourly, daily and monthly RVRs are very similar and their variation ranges are also approximately the same in the two cities. This similarity in hourly, daily and monthly distribution determines the inevitable approximate equality of the annual heating and cooling RVRs in different cities and thus the proposition is right in a wide range.     

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。     

Are the relative variation rates (RVRs) approximate in different cities for the same building with the same outer-window reform?

By analyzing and comparing hourly, monthly and classified cooling and heating energy consumption of Tampa and Guangzhou, it can be found that the reduction of heat transfer coefficient of outside window can obviously decrease annual heating need. Its effect is essentially similar to the reduction of outer-wall heat transfer coefficient. The reduction of outer-window heat transfer coefficient can significantly increase the heating or cooling RVRs of the hours without solar radiation (basic RVRs) and it can also increase the heating RVRs at the hours with solar radiation. However, it can just increase cooling RVRs at the hours with solar radiation limitedly. Only supplemented with restraining solar radiation effectively, it could raise the cooling RVRs significantly. Whatever any climatic conditions, the annual heating energy consumption is governed by the classification without solar radiation ($>80\%$) and annual cooling energy consumption is governed by the classification with solar radiation ($>90\%$). Therefore, in order to decrease heating energy consumption, the first choice is the improvement of envelope's thermal insulation performance while to decrease cooling need, the first measure is to restrain solar radiation and then supplemented with the improvement of envelope. It is shown by the research that under the same outer-window heat transfer coefficient (i.e., the same measure of outer-window thermal insulation is adopted for the same building), the heating RVRs are approximate and the cooling RVRs are also approximate in different cities. This paper proves at another angle the universalism of approximation of heating and cooling RVRs under different climatic conditions (or in different cities) for the same building with the same energy-efficient measure again.     

Identifications: the RVRs are approximate in different cities with the same energy-efficient measures

This paper takes $960{\mathrm{m}}^2$-model building as the analysis object and chooses two cities with great climatic discrepancy (Tampa of USA and Belgium) among the 19 background cities in favor of the author's proposition. By making comparisons based on the variation laws of hourly, daily and monthly energy-conservation rates (RVRs) of heating and cooling between the above two cities when taking the same energy-saving measures to the same building, we can find that although the annual hours, days and months in need of heating and cooling differ up to several times even tens of times in the two cities which have quite different climatic conditions, the distribution laws of hourly (microcosm), daily (super-microcosm) and monthly (sub-macrocosm) heating and cooling RVRs are very similar in the two cities. Just the similarity determines that the annual heating and cooling RVRs are approximate in different cities for the same building with the same energy-efficient measures. In addition, on further study it has been found that because the daily mean climate is closer to annual mean climatic statistics than the hourly one and the monthly mean climate is closer to annual mean climatic statistics than the daily one, the difference between the hourly and annual average RVRs is the largest, the difference between the daily RVRs and annual average RVRs is the second largest while that between the monthly and annual RVRs is the smallest. In this way, it can demonstrate the inevitability of approximation of annual RVRs in various cities when taking the same reforms to the same building.     

Are the annual relative variation rates of energy consumption approximate in different cities with the same shading coefficient?

This paper studies two buildings located in 10 background cities of China and USA with tools of DOE-2 and characteristic temperature method (CTM), respectively. The aim here is to find the variation laws of annual heating and cooling energy consumptions and their relative variation rates (RVRs) with the decrease of sun-shading coefficient. By exploration, we can find that when sun-shading coefficient declines, the prediction of CTM on the annual heating and cooling energy consumptions and their RVRs is the same with that of DOE-2 in tendency while the prediction of CTM on annual heating energy consumption and its RVRs is quite different from that of DOE-2 quantitatively. By further study, we can also find that for the same building with the same sun-shading coefficient, the annual RVRs of heating needs are close and those of cooling needs are also close in cities with various meteorological conditions. The annual RVRs of heating and cooling energy consumption are dependent on sun-shading coefficient. When sun-shading coefficient is bigger, the annual RVRs of heating energy consumption are higher in every city while those of cooling needs are lower. On the other hand, when sun-shading coefficient is smaller, the annual RVRs of cooling needs in each city significantly increase while those of heating needs decrease mildly, thus the gap between them is enlarged.     

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.     

Identifications: inevitability of RVRs being approximately the same under different meteorological conditions when taking the same energy-saving measures in the same building

By making comparative research on hourly, daily and monthly energy consumption differences and also on energy conservation rates of heating and cooling when taking the same energy-saving measure in the same building in typical-year meteorological conditions (WDB1) and artificial meteorological conditions (WDB2), we can find from this paper that although the hourly heating and cooling load has great differences when making the same energy efficient measure in the same building under WDB1 and WDB2, the distribution laws of hourly energy efficiency rates (RVRs) of heating and cooling are very similar. It is just the similarity that determines the inevitability of approximation of annual energy conservation rates of heating and cooling. The importance of this paper is that it reveals the common rule of building efficiency. When making the same energy-saving measure on the same type of building in different regions the annual energy consumption and its reduction of the building have a great difference between the regions and the energy conservation rates (RVRs) of the same measures are approximate. After taking some energy-saving measure on the same building in the same place, within the lifetime of the building, however different the local weather conditions over the years are, the energy consumption of different years and the energy reductions of the measure must be different. However, it can be foreseen that the energy conservation rate of any year is approximate after making energy-saving measures on the building. The reason for the above is that although climate changes between years, there is nothing more impractical in artificially modifying meteorological conditions (WDB2), which provides a powerful theoretical basis for every country to lay down design standard for energy efficiency.     

Are the relative variation rates (RVRs) approximate in different cities when the same energy-efficiency reform is taken to the same building?

On the assumption that the same envelope reform is made on two buildings located in 19 cities of China, America and Europe, this paper simulates the annual heating and cooling energy consumption before and after the reform with tools of DOE-2, DeST-h and the authors' characteristic temperature method (CTM), and makes further analysis on the relative variation rates (RVRs) of energy consumption. It can be found that the absolute reductions of annual heating and cooling needs may differ up to tens of times in different cities for the same buildings with the same energy-efficient measures. On the other hand, there is no obvious difference in initial investment for the same energy-efficient reform in various cities of a country or an economic district, therefore, the energy efficiency potentiality and economic value of the same reform are completely different under various climatic conditions, which illustrates that it is very important to harmonize the local climates when selecting an energy-efficient project in different locations. However, when the same measures are taken to the same building, the annual heating RVRs are approximate and the annual cooling RVRs are also approximate in different cities, which is the common rule of building energy efficiency.     

Are the relative variation rates (RVRs) of energy consumption approximate in different cities for the same increase of ventilation rate?

This paper makes simulations on the annual heating and cooling energy consumption of four kinds of buildings under the climatic conditions of 19 background cities in China, USA and Europe when ventilation rates increase from 0 to 1.5 vol/h, respectively by, CTM, DOE-2 and DeST-h. The simulation results by CTM show that the increments of annual heating and cooling may differ up to 10s of times or even more than 100 times in different cities for the same building with the same increase of ventilation rates, while the annual heating and cooling RVRs are both approximate in different cities. For the same building with the same increase of ventilation rate in the same city, its annual heating RVRs are far higher than its annual cooling RVRs. The above conclusion can be reached for any building whether with various envelopes or with different shape coefficients.     

Research on the influence of air humidity on the annual heating or cooling energy consumption

Just taking 960 m² model building with improved envelope for example, this paper studies the influence of outside air humidity on the annual heating and cooling energy consumption and their relative variation rates (RVRs) and the discrepancy between temperature–humidity control (THC) and temperature control (TC) with the same increase of ventilation rates. The research shows that the discrepancy of annual heating and cooling RVRs is significant under different climatic conditions for the same building with the same increase of ventilation rates by the mode of THC. In general, the heating RVRs decline with the increase of average outside air humidity and the cooling RVRs rise with the increase of average outside air humidity. However, annual heating and cooling RVRs are both approximate in different cities under the climatic conditions of approximate annual average air humidity. The annual heating or cooling need by mode of THC is higher than or equal to the corresponding energy consumption by mode of TC and there exists a close relationship between the absolute increment of energy consumption and outside air humidity; furthermore, as the annual average air humidity increases, the absolute increment of annual cooling need increases while that of annual heating need decreases and both have good linear relation.     

相同建筑相同节能措施在不同气象条件下的负荷减少率

以广州、重庆、北京等12个城市为对象,分别以DOE-2中的TMY2,DeST—h中的TRY及修改的TMY2辐射数据,构建了36组完全不同的8760h气象数据库。利用特征温度法模拟计算相同建筑在围护结构改进前后单位建筑面积的全年空调和供暖耗能量。研究发现,对所涉及的城市,尽管因三种气象数据库（36组）显著不同,导致计算出的围护结构改进前后（72组）建筑全年空调供暖负荷、负荷减小量存在很大的差异,但是在不同气象条件下对模型建筑采取相同的节能措施。各城市全年空调负荷减小率（节能率）是相近的;各个城市全年供暖负荷减小率（节能率）也是相近的。从而证明了现行各国标准均规定围护结构K限值的通常做法是完全正确的。     

基于逐时太阳辐射强度与动态逐时负荷分析的太阳能空调系统设计要点研究——以天津市某办公楼项目为例

建筑的地理气候特征影响太阳能在建筑中的收集与利用。以天津市某办公楼项目为例,基于日照遮挡模拟分析确定集热器布置区域,并根据逐时动态冷负荷与热负荷综合情况确定集热器面积,以动态逐时负荷与供热(冷)量匹配的方法辅助备用能源设计,降低了系统的造价,提高了太阳能的利用率和建筑供能系统的稳定性,为后续其他项目太阳能空调系统的设计提供了借鉴。     

某办公楼空调系统能耗模拟

利用DeST软件对各区域全年逐时冷热负荷与空调系统的能耗进行了模拟计算,分析了不同窗墙面积比、遮阳构件对能耗的影响,确定南向窗墙面积比为0.34,由外挂石材形成的遮阳构件可降低全年累计冷负荷指标约2.18％.     

夏热冬冷地区住宅围护结构能耗的灵敏度分析

为得到围护结构各相关因素对建筑能耗影响的权重,采用EETP围护结构评价指标对空调、采暖能耗进行计算,分析了夏热冬冷地区上海、长沙、韶关和成都四个城市高层点式住宅围护结构各因素对空调、采暖及全年能耗的灵敏度,包括体形系数、窗墙比、遮阳系数、外墙/屋顶/外窗的传热系数、外墙/屋顶外表面的太阳辐射吸收系数。结果表明：窗墙比为25%时,墙体传热系数、体形系数和窗墙比依次是影响全年能耗的前三位主要因素,四个城市灵敏度分别为24.4%~35.8%、21.7%~32.0%和16.8%~31.1%;窗墙比为50%时,窗墙比、体形系数和遮阳系数依次是前三位主要因素,灵敏度分别为34.8%~45.6%,20.0%~44.3%和12.0%~47%;外墙和屋顶外表面太阳辐射吸收系数以及屋顶传热系数对建筑全年能耗影响均很小。     

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.     

西安地区办公建筑南窗水平遮阳研究

通过窗户的太阳辐射对建筑夏季空调能耗和冬季采暖能耗有着重要的影响,对于南向窗户来说水平遮阳方式比较有效.以西安地区办公建筑南向窗户为研究对象,借助Energyplus等软件,分析了夏季通过南窗太阳能辐射得热问题,综合考虑不同水平遮阳板宽度对建筑采暖和空调负荷的影响,得出了遮阳板最佳设计尺寸.     

Energy performance analysis on telecommunication base station

Telecommunication base station (TBS) has high indoor IT heat dissipation rate, and cooling load exists almost all year around. Energy consumption of air-conditioning system is 30–50% of the TBS entire energy. Envelope and heat pipe assisted air-conditioning system performances are investigated using annual hourly simulation software. In cold city Harbin, high insulation envelope is recommended to avoid heating requirement in winter; and in warm city Guangzhou, low insulation envelope is recommended to reduce the annual cooling load. Shading and roof ventilation have little impact on the reduction of cooling load. Simplified analysis method based on daily average steady values is proposed, which can reveal the main performance influencing factors and clearly direct the main approach in energy saving. The simplified method can accord well with numerical results and tested results available in literature. Contribution of each heat source can be clearly gained and analyzed, solar radiation does not possess large effect in TBS. Ideal thermal resistance with no heating or cooling requirement is then derived, envelope can be easily optimized and contribution of such kind of outdoor cooling source method using heat pipe can be easily obtained.