Energy-efficient houses built according to the energy performance requirements introduced in Denmark in 2006

In order to meet new tighter building energy requirements introduced in Denmark in 2006 and prepare the way for future buildings with even lower energy consumption, single-family houses were built with the purpose to demonstrate that it is possible to build typical single-family houses with an energy consumption that meets the demands without problems concerning building technology or economy. The paper gives a brief presentation of the houses and the applied energy-saving measures. The paper also presents results from measurements of the overall energy use, indoor climate and air tightness. Furthermore, results from detailed calculations of the utilization of electricity-related heat gains are presented. Looking at the energy consumption in relation to the new energy requirements, the paper concludes that the single houses can relatively easily keep the future energy demands. The energy consumption of the houses is on a level corresponding to a classification as “low-energy house class 2” or an energy consumption of 75% of the required maximum energy consumption. With minor modifications, some houses could be classified as “low-energy building class 1” corresponding to an energy consumption of only 50% of the required and almost the level of typical passive houses.     

双层铝板通风坡屋顶在湖南农村住宅节能改造中的应用

房屋建筑物顶部屋面全年受阳光热辐射,是建筑物受热最多也是最集中的部位。对于普通单层建筑,夏季屋面所得热量占建筑各面总热量的37%左右,而在冬季则能占到50%以上,导致屋顶面隔热能力的强弱直接影响了屋内的内热环境和能耗状况。湖南中北部农村的村民民房绝大部分使用小青瓦或机制瓦铺顶,下方形成阁楼与内屋相通,在没有采取隔热措施的情况下,夏季室温需要另外耗能降温。对此,以湖南农村住宅为实例,对双层铝板通风坡屋面的隔热改造技术在农村建筑节能工程中的应用进行了阐述分析。     

东北地区太阳能农宅设计和研究

针对东北地区的气候特点和农村的自然条件,根据太阳能房的工作原理,通过对农村住宅进行合理的户型设计和构造设计,有效利用太阳能解决冬季农宅采暖和夏季降温,并对太阳能产生的经济效益进行分析,通过试点工程表明,太阳能住宅设计大大提高了农宅的热工性能,既降低了冬季农宅的采暖能耗,也调节了夏季的室内温度,达到了节能、环保、经济的目的,走可持续发展的道路是可行的。     

Investigation of energy performance of newly built low-energy buildings in Sweden

Energy use in the built environment represents a large part of total energy use in Sweden and is one important sector where energy conservation needs to be significantly improved in order to meet the national implementation of the European goals. One key question that needs to be investigated in relation to these goals is the performance and implementation of passive or low-energy houses. This paper presents results and an evaluation of a newly built house in an area with passive houses in Linköping, Sweden. Nine passive houses were built with the aim to be energy efficient, with an annual space heating demand of 21 kWh/m², and at the same time to have the same visual appearance as any other building in the surrounding area.This study evaluates the energy performance of a residential area with low-energy buildings based on Building Energy Simulation (BES) (IDA ICE 4), and measurements from the real object. Both annual and hourly validation is performed using room by room modeling and internal heat gains. A novel approach to internal heat gain modeling is presented using time-use data (TUD). The results show possible improvements in the design, the building envelope and in the heating control.     

Empirical validation of different internal superficial heat transfer models on a full-scale passive house

Being highly insulated, low-energy buildings are very sensitive to variable solar and internal gains. In this context, some modelling assumptions frequently used in simplified building energy simulation tools might be called into question. While higher insulation levels reduce the influence of heat transmission through opaque walls, absorption of solar and internal gains at inner wall surfaces, and indoor superficial heat transfers, become concerning. The convective and long-wave radiative heat transfer models are investigated in COMFIE, a dynamic energy simulation platform. More detailed internal heat transfer models are developed by decoupling convective and long-wave radiative heat transfers and using time-dependent coefficients. Furthermore, an empirical validation process on both simplified and detailed models is carried out using measurements from a full-scale experimental concrete passive house, addressing the model uncertainty vs. complexity issue.     

Heat transfer modelling on windows and glazing under the exposure of solar radiation

Due to the effect of solar radiation on windows and glazing system the evaluation of heat flow is of primary importance in modeling the thermal performance within building interiors to account thermal comfort and overall energy consumption of a building. In this context the optical properties of window glazing are measured to determine the percentage absorption of incident solar radiation. An experimental study was performed in a room to measure the glazing surface temperature due to the global radiation on it. The corresponding window plane global radiation and horizontal global radiation were measured outside for simulation. Mathematical models have been developed to simulate the window plane solar radiation and corresponding glazing surface temperature aiming at validating the measured values. The thermal model is concerned with laminar heat transfer for natural and forced convection process according to the ambient conditions. The estimated errors between experimental and simulated values of window plane radiation and glazing temperature are shown to be within ±5%. Using the developed thermal model the heat flow inside the room through windows is determined. Thus overall heat transfer coefficient of glazing (U-factor) and the Solar Heat Gain (SHG) of building interior have been predicted from the simulation.     

草砖房在北方农村地区适宜性研究

选择适宜的墙体材料可有效地降低房屋在使用过程中的能耗,以在建的草砖作为墙体填充材料的房屋为研究对象,通过对建筑室内外温湿度、墙体表面温度的测试分析及其全年采暖能耗模拟分析,对比在其他同等条件下使用普通黏土砖和草砖的能耗情况,结果表明,草砖具有良好的隔热性能,并有一定的湿度调节作用,且其保温特性优异,在大同地区较之于黏土砖节能61.69%。此外,还对比了不同地区草砖房较之于普通黏土砖建筑的能耗状况,结果显示,哈尔滨、大同、西安地区草砖房的节能率分别为56.59%、61.96%、65.55%。据此提出草砖墙体材料应用于严寒、寒冷地区的农村住宅,其节能效果明显,具有普遍的适应性。     

北方寒冷地区小城镇住宅供暖节能研究

通过对我国北方寒冷地区小城镇供暖住宅的室内温度、供暖煤耗及围护结构热工性能的实测,评价了小城镇供暖住宅的供暖室内热环境,研究了供暖煤耗及围护结构的保温性能。提出合理选择供暖热源、改进供暖方式、改善围护结构的保温性能、提高热用户的节能意识是小城镇供暖节能的有效措施。     

复合相变墙体应用于被动式太阳房的初步研究

以冬季日照率较高、太阳辐射强度大的北京地区为研究对象,依据建筑热物理学、传热学以及相变贮能理论,结合计算机模拟分析以及实验的方法,研究了复合相变墙体材料在被动式太阳房中应用的可行性,为相变蓄热技术以及可再生能源在建筑节能中的应用提供参考.     

Building Energy use Compilation and Analysis (BECA): An international comparison and critical review. Part A: New residential buildings

The potential for energy conservation in space heating of new residential buildings is characterized using results from computer analysis, and from a survey of low-energy houses. Simulations of the energy requirements of a prototypical house in the United States at different levels of conservation have shown that much higher levels of conservation than those presently employed in new houses result in minimum life-cycle cost. Measurement taken in actual houses indicate that very low space heating energy requirements — comparable to that now used for domestic water heating — can be achieved in new houses by attention to insulation, infiltration, and solar-design principles. We conclude that building standards should be made more stringent to hasten the adoption of cost-effective conservation measures.     

天津农村住宅围护结构调研及节能设计

针对天津农村住宅普遍存在的能耗高、室内舒适度差等问题,通过对农村住宅的体形系数、窗墙比、围护结构传热系数的分析,提出适合天津农村住宅的围护结构节能设计方案。建议采用天然材料和适宜的技术,以耗费最少的资源,实现农村住宅节能目标。     

青海省藏区被动式太阳房全年室温模拟分析

本文利用TRNSYS软件建立了不同种类被动式太阳房的传热模型,并根据青海省藏区(黄南州和玉树州)的气候特点,对全年室内空气逐时温度变化进行了模拟和分析,并对青海省藏区被动式太阳房的应用提出了推荐策略。     

HELP (house energy labeling procedure): methodology and present results

The problem of energy certification in the housing stock remains a priority for the European Community Member states referring to the European Directive N. 93/76/EEC. It is also a certainty that the potential for energy conservation in the existing buildings is very large, and there is a need for a rating of their energy performance.Facing this problem and the lack of tools, we chose to develop a measurement based approach, often referred to as an identification method. The principle of this method is to derive the thermal behavior from a continuous recording of internal temperature within the building in response to outdoor climate (temperature and solar radiation) and internal loads (heating and appliances). The derived parameters are then used to calculate a normalized heating annual consumption (NHAC) for a standard climate and a standard operation of the building (set point temperature, air change rate and casual gains).The paper presents the proposed methodology for single family houses, including the experimental equipment, the monitoring protocol and the calculation tool. Results are also discussed for a set of 10 monitored houses within Europe. Although some limitations of the methodology were found, that will require deeper investigations, the NHAC was found a robust indicator to deal with occupants’ influence.     

银川地区被动式太阳房的室温预测

被动式太阳房是一种经济有效地利用太阳能采暖的建筑,银川地区太阳能热水器已经得到了广泛的应用,但被动式太阳房的应用较少。本文对银川地区直接受益窗与集热蓄热墙的组合式太阳房的室内温度进行预测,分析其热舒适性,以便今后更近一步的研究。     

西北地区生态民居及室内热环境

我国西北荒漠地带,生态环境脆弱,可持续发展面临巨大的资源和环境压力。以银川市碱富桥村新农村建设为研究对象,科学规划合理设计,依据当地丰富的太阳能资源提出了被动式太阳能新型生态民居设计,新民居综合利用了被动式太阳房、草砖、稻壳板等多种生态建筑技术。建成后对太阳辐射、室内外温湿度、平均辐射温度以及预计平均热感指数PMV等进行了现场测试,对室内热环境的形成原因进行了分析,并对夏季室内通风进行了模拟分析。测试和模拟表明,新民居冬季温暖、夏季凉爽,具有较好的室内热环境质量,对于西北地区新农村建设具有重要借鉴意义。     

A simple model for assessing the energy performance of windows

A simple model for the annual energy balance of the window taking solar radiation and heat losses into consideration has been further developed and analysed. Hourly meteorological data for the solar irradiation and the outside temperature are used together with the optical and thermal performance of the window to evaluate the net energy heat flow through a window. The model renders a very simple way to compare different advanced windows in different geographical locations, orientations and buildings using basically only the balance temperature as building input. The energy balance and the cost efficiency for several glazing combinations are evaluated for buildings with different balance temperatures in a typical mid-Swedish climate. This model has a potential to be used for energy rating of windows.     

Five-year data of measured weather,energy consumption,and time-dependent temperature variations within different exterior wall structures

This paper presents coherent 5-year measured data that have been gathered for analyses of building energy consumption and thermal performance of exterior walls. The data is also very suitable for calculations and simulations of heating and cooling energy need of buildings. The data was collected from six identical test buildings, having exterior walls that are constructed of different building materials. The data include the following: indoor–outdoors temperatures; temperatures at various depths within the northern, southern, eastern, and western exterior wall facades; indoor–outdoors relative humidity, heating energy, wind speed and direction; air tightness, infiltration, and horizontal global solar radiation. A computer system (data logger) was used to monitor, check, calculate, integrate, and save the data acquired from approximately 520 sensors in each test building. Measurements were taken with a time interval of 20 s. The 20 s values were then integrated over a time interval of 30 min and the minimum, maximum, and mean values were subsequently stored to a computer database. Analyses of the results indicated that temperatures within the buildings’ exterior walls are constantly changing and, that occasionally the flow of conduction heat is reversed (i.e. outside–inside) due to solar radiation. For accurate results of temperature distribution and the actual heat losses through building envelopes, none steady-state calculations are essential. Depending on the intensity of solar radiation and the material characteristics of the walls, temperature gradient at the inner surfaces of exterior walls may become milder compared to that of the outer surfaces.     

太阳能富集地区住宅建筑非平衡保温研究——拉萨市供暖期太阳辐射分析与室内热环境测试

在有供暖需求的太阳能资源富集地区,由于太阳辐射强烈,住宅建筑各个朝向外墙,尤其是南北向的外墙所接收的太阳辐射量差异很大,为了更有效地利用太阳能并降低保温成本,这种差异应表现在建筑围护结构保温性能的设计中.本文通过对拉萨市标准年气象数据库的分析得到了其住宅建筑各朝向外墙供暖季内获得的太阳辐射量.与内地城市相比,拉萨市太阳能资源丰富且朝向差异很大,非平衡保温具有一定的实际意义.另外,冬季现场测试表明无供暖建筑的南北朝向房间热环境有所不同,南向房间测试周期内基本处于人体舒适范围内,而北向房间始终偏冷,远离人体热舒适区域,有供暖需求.     

寒冷B区的高性能节能建筑能耗计算分析

针对寒冷B区的5个典型城市,研究分析了气象文件、系统性热桥、高性能窗等对建筑能耗的影响。提出对气象文件中的温度、太阳辐射分析,可以确定供暖空调起始日期及对建筑能耗影响的比例。利用模拟计算的方法,外墙外保温的单个锚栓对系统传热系数增加值为小于等于0.002 W/(m^2·K)。对高性能窗的性能进行研究,得出窗户的气密性及玻璃层数的配置,直接影响建筑能耗趋势,且采用活动外遮阳的总能耗比固定遮阳的降低9%左右。     

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.