Progress report from Sweden

A huge investment in energy conservation is a feature of Swedish political life. The generous system of grants and loans to householders, the tightening of building regulations and the innovatory development projects, notably with solar energy, are reviewed in this article. It continues our series of progress reports from countries represented on CIB working commission W67 — energy conservation.     

Building energy-efficiency standards in a life cycle primary energy perspective

In this study we analyze the life cycle primary energy use of a wood-frame apartment building designed to meet the current Swedish building code, the Swedish building code of 1994 or the passive house standard, and heated with district heat or electric resistance heating. The analysis includes the primary energy use during the production, operation and end-of-life phases. We find that an electric heated building built to the current building code has greater life cycle primary energy use relative to a district heated building, although the standard for electric heating is more stringent. Also, the primary energy use for an electric heated building constructed to meet the passive house standard is substantially higher than for a district heated building built to the Swedish building code of 1994. The primary energy for material production constitutes 5% of the primary energy for production and space heating and ventilation of an electric heated building built to meet the 1994 code. The share of production energy increases as the energy-efficiency standard of the building improves and when efficient energy supply is used, and reaches 30% for a district heated passive house. This study shows the significance of a life cycle primary energy perspective and the choice of heating system in reducing energy use in the built environment.     

The impact of consumer behavior on residential energy demand for space heating

Besides technical parameters, consumer behavior is the most important issue with respect to energy consumption in households. In this paper, the results of a cross-section analysis of Austrian households are presented. The impact of the following parameters on residential energy demand for space heating have been investigated: (i) thermal quality of buildings; (ii) consumer behavior; (iii) heating degree days; (iv) building type (singleor multi-family dwellings). The result of this investigation provides evidence of a rebound-effect of about 15 to 30% due to building retrofit. This leads to the conclusion that energy savings achieved in practice (and straightforward the reduction in CO₂ emissions) due to energy conservation measures will be lower than those calculated in engineering conservation studies. Straightforward, the most important conclusions for energy policy makers are: (i) Standards, building codes, respectively, are important tools to increase the thermal quality of new buildings; and (ii) Due to prevailing low energy prices, a triggering tool has to be implemented which may be rebates or loans.     

Measurements of occupancy levels in multi-family dwellings—Application to demand controlled ventilation

The occupancy level of dwellings is an important parameter to know to determine the energy efficiency, energy use and indoor air quality, especially in low-energy buildings where the user-related energy uses, such as household electricity and domestic hot water heating, are significant parts of the energy balance in a building. For residential buildings, there is a lack of occupancy level data, which also needs to be resolved over time, in a way so that both short term and long term variations can be described. As a part of an ongoing study, occupancy levels were measured as building average levels in 18 apartment buildings containing 342 apartments in total with readings every 30 min for more than a year. Averages and standard deviations of occupancy level, and variation in occupancy during the year, week and day respectively are presented. The results show a highly varying occupancy level over time, which indicates the potential of demand controlled ventilation in dwellings.     

瑞典集中热泵系统区域供热供冷经验以及在中国的和谐化应用

20世纪80年代,瑞典开始将热泵系统区域供热作为一项重要市政基础建设进行大规模的安装,在短短几年内,大型热泵站在瑞典中型以上城市得以运行,10年后,使用热泵系统实现区域供冷的热潮相继而至,最初通常与区域供热相结合,一直以来,瑞典都是世界上成功应用热泵技术实现区域供热供冷的领军国家,致力于完善建设并且国际化的推广本土经验,当今．节能减排和新型环保型能源的应用成为中国在快速发展进程中的关键词．成就了将热泵1区域供冷技术以及在欧洲的应用经验引入中国的大好时机,本文将介绍集中热泵系统供热供冷系统的优点,瑞典的热泵系统成功经验以及此项技术在中国因地制宜的和谐化应用,     

Beyond the code: Energy, carbon, and cost savings using conventional technologies

As states in the U.S. adopt new energy codes, it is important to understand the benefits for each state and its building owners. This paper estimates life-cycle energy savings, carbon emission reduction, and cost-effectiveness of conventional energy efficiency measures in new commercial buildings using an integrated design approach. Results are based on 8208 energy simulations for 12 prototypical buildings in 228 cities, with 3 building designs evaluated for each building-location combination. Results are represented by easy-to-understand mappings that allow for regional and state comparisons. The results show that the use of conventional energy efficiency technologies in an integrated design framework can decrease energy use by 15-20% on average in new commercial buildings, and over 35% for some building types and locations. These energy reductions can often be accomplished at negative incremental life-cycle costs and reduce a building's energy-related carbon footprint by 9-33%. However, generalizing these results on energy use, life-cycle costs, and carbon emissions misses exceptions in the results that show the importance of location-specific characteristics. Also, states do not appear to base energy code adoption decisions on either potential energy savings or life-cycle cost savings.     

Benchmarking Hong Kong and China energy codes for residential buildings

Mandatory energy codes to curb energy use of residential buildings have been formally launched in China for more than two decades but little has been publicized in literature. Similar codes are not available for residential buildings in Hong Kong, but most residential buildings in Hong Kong, especially public housing estates, are HK-BEAM certified to demonstrate their compliance with regulatory and basic design requirements. Given HK-BEAM is internationally recognized and there are doubts about the effectiveness of the China codes, how the energy efficiency of the HK-BEAM certified buildings compare with buildings in compliance with the China codes is of interest to most building designers and policy makers. This paper describes how the energy efficiency of a case study building in compliance with the China codes compare with the one in compliance with HK-BEAM. The energy simulation by HTB2 and BECRES reveal that the case study building in compliance with the China codes is 51.1% better in energy use. In the study, the relative impact of each compliance criterion on energy use and cooling load has been quantified by sensitivity analysis. The sensitivity values indicate that energy use is most sensitive to air-conditioning operation hours, indoor design temperature, coefficient of performance (COP) of the room air-conditioners (RAC) units, and the envelop characteristics. The results of this study indicate that a HK-BEAM certified building cannot satisfy the China codes requirements. This provides good reference to the policy makers, the building owners, and to the China and Hong Kong Governments when considering reciprocal recognition of building energy codes.     

某游泳馆空调节能设计、运行能耗分析

游泳馆建筑温湿度要求与其他公共建筑不同，能耗较大，在舒适度和节能之间选择一个合适的点，并据此合理地确定其空调方式，对游泳馆建筑节能至关重要。目前国内关于游泳馆等方面的设计规范、标准尚不完善，成功的案例不多，通过总结南京市某游泳馆投入使用后1年的监测数据，从实践的角度探讨游泳馆建筑空调节能设计思路。     

Heating control schemes for energy management in buildings

Because of both the global energy crisis and the necessary improvement of energy efficiency in buildings, one of the largest sectors of energy consumption and greenhouse gases emissions, a strategy allowing managing energy resources is proposed. Its aim is reducing energy consumption and promoting the use of renewable energy, while ensuring thermal comfort, when heating “multi-energy” buildings, thanks to indoor temperature control schemes. Three schemes (based on a commonly used PID controller and on the combination of PID and model predictive or fuzzy controllers) were tested in simulation, using dynamic models describing the thermal behavior of a building, and fully met the management strategy's requirements, especially reducing the consumption of fossil energy. Three criteria describing the way energy is used and controlled in real-time were defined with the aim of evaluating the control schemes performance and adapting the strategy to the specific use of a building. The PID-MPC provided the best results while the PID-FLC proved to be a very good compromise, thanks to both the flexibility and the adaptability offered by fuzzy logic, between the easy-to-develop but not-very-efficient PID and the efficient but hard-to-develop PID-MPC.     

Developing a new library of materials and structural elements for the simulative evaluation of buildings’ energy performance

Contemporary building energy simulation programs are not only used by researchers but also are common tools in the hands of engineers and architects. Most of them are using databases of materials and structural elements, with characteristics originating from the country or the broader region where the specific program was developed. Thus, often the particularities met in other countries are not considered. Such a database of materials and constructions systematically used in the Greek building sector was developed for use with the simulation program EnergyPlus, which has become quite popular over the last years. In order to determine the applicability of the database, the energy behaviour of a typical multistory, multifamily building was simulated, having the exact materials and structural elements and patterns used in Greece. Furthermore, different thicknesses of insulation were simulated, corresponding to local climatic conditions and, even more important, to different dates of the building's construction. The results are presented and discussed in this paper.     

LCA-based environmental assessment of the use and maintenance of heating and ventilation systems in Dutch dwellings

Buildings contribute significantly to the human-induced environmental burden. This comes not only from construction and demolition but also from activities throughout the operational phase – building maintenance and energy use for climate control. This paper describes how life cycle assessment (LCA) methodology can be applied to quantitatively assess the environmental performance of the use and maintenance of heating and ventilation systems. The studied climate systems include individual non-condensing boilers, condensing boilers and heat pumps on exhaust air for heating and hot tap water combined with either collective mechanical exhaust ventilation or individual balanced ventilation with heat recovery. This study shows that a heat pump causes the highest environmental burden of all the assessed climate systems due to the electricity needed for operation, high material content of the system and the refrigerant used. If the electricity used by the heat pump is generated fully by local photovoltaic cells, environmental performance will improve, but not for all environmental impact categories. Climate systems that reduce energy demand for heating, such as ventilation with heat recovery, will reduce the environmental impact related to energy use for space heating. However, if the electricity used to operate the system increases, along with the material content of the systems and distribution networks, other environmental impact categories than those related to space heating will also increase. Finally, maintenance frequency and related transportation of maintenance workers have a marginal effect on total environmental impact.     

What next for energy-related building regulations?: the occupancy phase

Building regulations are important policy instruments for increasing building energy efficiency. However, when it comes to actual energy use, studies have shown that improvements in building energy efficiency are offset by changes in the inhabitants’ comfort practices. Nevertheless, the improvement of energy efficiency continues to be a cornerstone in building regulations, with no consideration of how this simultaneously influences everyday practices. The example of Danish building regulations, which are among the strictest in Europe, is critically reviewed for the implications regulatory design can have for reducing energy consumption. Based on readings of policy documents, consultancy reports and research papers from the last two decades, this paper outlines where things go amiss during a building’s lifetime if a user perspective is excluded. The focus is on three phases: the development of new building technologies, the design and construction of buildings, and occupancy. The question of how building regulations could be redesigned to regulate energy use better is explored, along with what research and strategies are needed within four domains: developing alternative measures to energy per square meter; developing more advanced models simulating occupancy; improving feedback technologies’ usability; and the increased use of commissioning and post-occupancy evaluations.     

美国摩天大楼发展史与中国城市摩天大楼发展思路

本文通过美国摩天大楼一个世纪以来的发展过程,分析其产生的社会经济和历史文化背景,揭示摩天大楼的空间区位对城市ＣＢＤ的牵引、阻滞和位移作用。特别是九十年代以来信息高速公路的建设,将对摩天大楼的发展趋势产生深远影响。上述研究,对我国刚刚兴起的摩天大楼建设热有所借鉴。     

Analysis of annual heating and cooling energy requirements for office buildings in different climates in Turkey

A great amount of world energy demand is connected to the built environment. Electricity use in the commercial buildings, accounts for about one-third of the total energy consumption in Turkey and fully air-conditioned office buildings are important commercial electricity end-users since the mid-1990s. In the presented paper, the interactions between different conditions, control strategies and heating/cooling loads in office buildings in the four major climatic zones in Turkey – hot summer and cold winter, mild, hot summer and warm winter, hot and humid summer and warm winter – through building energy simulation program has been evaluated. The simulation results are compared with the values obtained from site measurements done in an office building located in Istanbul. The site-recorded data and simulation results are compared and analyzed. This verified model was used as a means to examine some energy conservation opportunities on annual cooling, heating and total building load at four major cities which were selected as a representative of the four climatic regions in Turkey. The effect of the parameters like the climatic conditions (location), insulation and thermal mass, aspect ratio, color of external surfaces, shading, window systems including window area and glazing system, ventilation rates and different outdoor air control strategies on annual building energy requirements is examined and the results are presented for each city.     

Fossil Fuel Free Växjö

The paper describes and analyses the work of Växjö to become a green city. Reduced energy use, alternative energies, alternative housing and reduced carbon dioxide emissions are all steps on the path of progress to a fossil fuel free future.     

上海市某小型办公建筑冬季采暖能耗监测及分析

本文选取上海地区某小型办公建筑开展冬季采暖用能实测,利用智能计量监测平台获取冬季工况的室内热湿环境和空调运行能耗实时数据,对比了空调电耗模拟结果和实测结果的差异,并对产生差异的原因进行了分析。该办公建筑的冬季单位面积空调电耗实测值为22.40 kW h/m^2,模拟值高达34.20 kW h/m^2,二者差异或因室内温度,通风量设定与实际使用情况偏离导致。     

小区供热节能改造的新尝试

通过对数个小区供热系统节能情况的调研,证明供热水系统失调和建筑物围护结构的保温性能差是建筑耗能的主要原因。按照分阶段实现民用建筑节能目标的要求,在对供热系统进行改造的同时,抓住住户房屋装修改造的机会,引导住户将房屋的保温改造纳入到装修项目中。通过在两方面的共同努力,解决了供热系统失调问题,提高了供热质量,降低了运行费用。更重要的是通过改造工程的实施,将建筑节能的理念全方位的体现出来,为今后同类小区进行节能改造提供可借鉴的经验。     

Evaluation of traditional architecture in terms of building physics: Old Diyarbakír houses

Diyarbak?r is located in the southestern part of Turkey. Traditional Diyarbak?r houses are successful examples of buildings adapted to a hot dry climate. This is achieved by conforming to an old style of living and by the requirements and the use of local materials. In this study, the general architectural properties of the traditional houses of Diyarbak?r, their layouts, plan types, building envelope and facade elements are evaluated in terms of building physics criteria. Today, in spite of new technological advances, techniques and materials, identical buildings are still being built, and climatic design is not considered important in Diyarbak?r. As a result these buildings do not provide shade and cool spaces, and thus cause thermal discomfort, or increase in the use of energy. The aim of this study is to emphasize the importance of the features of traditional buildings in terms of designing energy efficient, to provide appropriate buildings for the environment.     

基于综合集成研讨厅方法的节能建筑建设体系的研究

“综合集成建设体系”是现代工程建设的重要方向,将系统论中的综合集成研讨厅方法应用于节能建筑设计时,需要包括建筑师、结构工程师、设备工程师、材料专家、节能技术专家、心理学家等与建筑行业相关的各行业专家的全程参与。综合集成建设体系是一个开放式的设计平台,在满足建筑使用功能的前提下,追求建筑全生命周期内的最优化节能。体系涵盖了建筑优化、资源优化、能源优化、材料优化、环境优化、智能控制优化和经济优化等7个方面。利用节能建筑综合集成建设体系,建设者们可以全面把握节能建筑建设。