Investigation of building height and roof effect on the air velocity and pressure distribution around the detached houses in Turkey

Heat losses from buildings occur to a great extent through external walls. As compared to other types of buildings detached houses have fewer stories constructed in open places with less environmental shelter against wind. In urban and rural settlements, the wind effect on houses with roof remains as an important subject of study. More specifically, the role of roof as an insulator and the effect of roof on forced convection from buildings need to be considered in this context. In this study, we have investigated the potentials of roofs for reducing the wind effect on the detached houses during winter months in Kayseri, a midsize city in Turkey located at 38.44°N and 35.29°W Turkey.For this purpose, four different detached house scenarios are taken into account. They are (i) without roof and one storey, (ii) with roof and one storey, (iii) without roof and two storey and, (iv) with roof and two storey. For each scenario, air velocity and pressure distributions in front and back sides of the house are investigated using finite volume methods with FLUENT software. The evaluation of velocity and pressure distributions reveals the importance of roof in reducing the wind effect on houses.     

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。     

严寒地区农宅阳光间节能及玻璃优化分析

随着人们对室内环境要求的提高，我国农村住宅建筑（简称：农宅）的能源消耗逐年增加。为减少农宅能耗，降低二氧化碳排放，满足节能需求，提出一种附加阳光间的被动农宅形式。通过EnergyPlus对该附加阳光间农宅进行了分析，获得了其采暖期的建筑能耗，研究了附加阳光间玻璃层数、填充气体及空气层厚度等因素对农宅能耗的影响，并优化了附加阳光间的玻璃结构。研究结果发现，与传统农宅相比，在农宅南侧附加阳光间，可减少建筑采暖能耗1115.64 kw·h。双层玻璃内填充气体种类和空气厚度对建筑能耗影响较大。其中，填充氪气时建筑能耗最低，空气层厚度9mm时建筑节能效果最好。     

夏热冬冷地区居住建筑节能研究的进展

我国的建筑节能工作已经进入第二阶段,夏热冬冷地区成为节能工作的重点。本文综合介绍了夏热冬冷地区的气候特征、建筑节能研究的方法及标准化工作的进展。     

The revival of the traditional Bosnian wood dwellings

This paper presents the results of research regarding the possibilities of the revival of the traditional Bosnian single-family house. The architectural design, spatial organization, and connection with the natural environment make it a valuable example of residential architecture. The use of local natural materials such as wood, stone, and adobe brick, brings this typology back into the limelight. This study illustrates that due to the increasing need to save energy, the importance to use natural materials, and integration of sustainable design into architectural design processes, our contemporaries turn to past examples in order to reference benchmarks combined with cutting edge technology for buildings of the future. Because Bosnia has large wooded areas, and a policy goal is to use local resources, the research aim was to establish if modern prefabricated wooden houses can reproduce traditional Bosnian architecture while meeting the highest energy efficiency requirements. Many Bosnians fear that traditional Bosnian architecture will be lost due to new construction, therefore there is opposition against the harmonization of standards. The solutions for redesigning traditional Bosnian single-family homes to meet energy efficiency requirements were obtained using the “BuildOpt_VIE” dynamic thermal simulation software. It was used to find optimal solutions in building physics, along with several variations to be applied during construction of new buildings and reconstruction of existing buildings. This research sets a foundation for further developments in contemporary individual residences, optimized according to recent building physics standards. The purpose of this paper is inter alia to show that nothing stands in the way to harmonize technical guidelines and regulations in the field of energy-efficient buildings in Bosnia and Herzegovina (B&H), and the adaption of existing norms. Despite the EU requirements as mandated in the Energy Performance of Buildings Directive, the rich architecture of B&H has potential to fulfill the directive’s conditions. By selecting the best solutions from the rich architectural tradition of B&H and optimizing the architectural design and building physics, B&H takes a step towards EU integration. Here, we show the possibility to keep traditional architecture while achieving state of the art energy efficiency.     

Building energy efficiency labeling programme in Singapore

The use of electricity in buildings constitutes around 16% of Singapore's energy demand. In view of the fact that Singapore is an urban city with no rural base, which depends heavily on air-conditioning to cool its buildings all year round, the survival as a nation depends on its ability to excel economically. To incorporate energy efficiency measures is one of the key missions to ensure that the economy is sustainable. The recently launched building energy efficiency labelling programme is such an initiative. Buildings whose energy performance are among the nation's top 25% and maintain a healthy and productive indoor environment as well as uphold a minimum performance for different systems can qualify to attain the Energy Smart Office Label. Detailed methodologies of the labelling process as well as the performance standards are elaborated. The main strengths of this system namely a rigorous benchmarking database and an independent audit conducted by a private accredited Energy Service Company (ESCO) are highlighted. A few buildings were awarded the Energy Smart Office Label during the launching of the programme conducted in December 2005. The labeling of other types of buildings like hotels, schools, hospitals, etc. is ongoing.     

Life-cycle energy of residential buildings in China

In the context of rapid urbanization and new construction in rural China, residential building energy consumption has the potential to increase with the expected increase in demand. A process-based hybrid life-cycle assessment model is used to quantify the life-cycle energy use for both urban and rural residential buildings in China and determine the energy use characteristics of each life cycle phase. An input–output model for the pre-use phases is based on 2007 Chinese economic benchmark data. A process-based life-cycle assessment model for estimating the operation and demolition phases uses historical energy-intensity data. Results show that operation energy in both urban and rural residential buildings is dominant and varies from 75% to 86% of life cycle energy respectively. Gaps in living standards as well as differences in building structure and materials result in a life-cycle energy intensity of urban residential buildings that is 20% higher than that of rural residential buildings. The life-cycle energy of urban residential buildings is most sensitive to the reduction of operational energy intensity excluding heating energy which depends on both the occupants' energy-saving behavior as well as the performance of the building itself.     

The potential for energy efficiency gains in the Canadian commercial building sector: A stochastic frontier study

The achievement of energy efficiency in commercial buildings is a function of the activities undertaken, the technology in place, and the extent to which those technologies are used efficiently. We study the factors that affect efficient energy use in the Canadian commercial sector by applying a stochastic frontier approach to a cross-section of Canadian commercial buildings included in the Commercial and Institutional Building Energy Use Survey (CIBEUS). Structural and climate-control features of the buildings as well as climatic conditions are assumed to determine the location of the frontier, while management-related variables including such factors as ownership type and activities govern whether or not the maximally attainable efficiency along the frontier is achieved. Our results indicate that although, on average, buildings appear to be fairly efficient, certain types of operations are more likely than others to exhibit energy efficiencies that are significantly worse than average. These results, along with those related to the effects of physical characteristics on the stochastic efficiency frontier, suggest that there is scope for focused policy initiatives to increase energy efficiency in this sector.     

Solar passive features in vernacular architecture of North-East India

Energy consumption in the buildings sector is very high and is expected to increase further due to improvements in living standard and increase in the world’s population. Incorporating appropriate solar passive features in climate responsive buildings are good options for energy conservation. This kind of building design integrates the micro-climate and architecture with human thermal comfort conditions and improves the building energy efficiency. From ancient times, people have used solar passive techniques in vernacular architectures throughout the world. However, still there is a lack of understanding, both in qualitative and quantitative aspects of solar passive techniques in vernacular architectures of North-Eastern India. A field study has been carried out to find out the various solar passive features in these naturally ventilated vernacular buildings in different bioclimatic zones of the region. The methodology of this work consists of survey of 150 households (50 houses in each bioclimatic zone) and, interacting with 300 occupants in each zone. The photographic evidences of solar passive features in these buildings are also collected. In this paper, the solar passive features related to building form and orientation, envelope design, shading, use of natural ventilation, internal space arrangements and activities of the habitants are explained for all the climatic zone of the region.     

Approaches to the design of sustainable housing with low CO2 emission in Denmark

Over the last year there has been a remarkable change in politicians' attitudes within Denmark and EU member states to the issue of climate change. This change in the political mindset is a result of the increasing frequency of high winds and flooding in Denmark and Europe, as well as in many other places around the world in recent years. This has resulted in an increasing challenge in terms of the planning, design and building of more sustainable buildings in order to reduce the use of energy for heating and cooling in new housing projects by bringing down the emission of CO₂ by reducing the amount of fossil fuel consumed by the built environment. This is crucial since carbon dioxide is one of the so-called greenhouse gases that is playing a major role in global warming. There is thus an increased focus on reducing the CO₂ level on a national and global scale. This article will look at the architectural and legislative changes in Denmark in relation to the increased political interest in the consequences of climate change. The article also discusses a survey of different types of approaches to the sustainable design of buildings and shows examples of new Danish housing projects that can minimise the use of energy for heating and cooling in the shape of detached houses, as well as a master thesis on high-rise houses.     

Quantity and electricity consumption of plug load equipment on a university campus

The percent of energy consumed by plug load equipment in commercial buildings is on the rise. Research conducted in the past has included surveying plug load equipment, measuring plug load electricity consumption and equipment operating patterns, and studying plug load reduction solutions in office buildings, but plug load energy use across other building types is poorly understood. A university campus, which houses many building types, presents a unique opportunity to understand plug load profiles across building types. In this study, an equipment inventory was performed in 220 buildings on Stanford University’s campus, totaling 8,901,911 ft² of building space and encompassing lab buildings, office buildings, recreation facilities, public space, and service buildings. Within these buildings, 110,529 pieces of plug load equipment were recorded. Energy consumption estimates were developed from published values and used to evaluate the aggregate plug load energy consumption of this equipment by equipment type and by building type. In total, it is estimated that the plug loads from these buildings consume nearly 50 million kWh per year and comprise 32% of the electricity consumption of the buildings surveyed. This data can be used to better target energy conservation efforts throughout multiple sectors.     

Synergic effects of thermal mass and natural ventilation on the thermal behaviour of traditional massive buildings

The energy policies about energy efficiency in buildings currently focus on new buildings and on existing buildings in case of energy retrofit. However, historic and heritage buildings, that are the trademark of numerous European cities, should also deserve attention; nevertheless, their energy efficiency is nowadays not deeply investigated. In this context, this study evaluates the thermal performance of a traditional massive building situated in a Mediterranean city. Dynamic numerical simulations were carried out on a yearly basis through the software DesignBuilder, both in free-running conditions and in the presence of an air-conditioning (AC) system. The results highlight that the massive envelope of traditional residential buildings helps in maintaining small fluctuations of the indoor temperature, thus limiting the need for AC in the mid-season and in summer. This feature is highly emphasised by exploiting natural ventilation at night, which allows reducing the building energy demand for cooling by about 30%.The research also indicates that, for Mediterranean climate, the increase in thermal insulation does not always induce positive effects on the thermal performance in summer, and that it might even produce an increase in the heat loads due to the transmission through the envelope.     

Comparison of energy conservation building codes of Iran,Turkey, Germany,China, ISO 9164 and EN 832

To improve the energy efficiency of buildings via compliance to regulation in Iran, Code No. 19 was devised in 1991. The code lacks high level aims and objectives, addressing the characteristics of Iranian buildings. As a consequence, the code has been revised and is not completely implemented in practice, and still remains inefficient. As with any energy coding system, this code has to identify the right balance between the different energy variables for the Iranian climate and way of life. In order to assist improvements to high level objectives of Code 19, this code is compared with ISO 9164, EN 832, German regulation, TS 825 of Turkey and China’s GB 50189 to understand how these have adapted international standards to national features. In order to test the appropriateness of Code 19, five case study buildings in Iran are assessed against Code 19 as well as Turkish standard TS 825 and the results are compared. The results demonstrate that Code 19 is efficient in calculations of building envelope, but it needs improvements in the areas of ventilation, gains from internal and solar sources. The paper concludes by offering suggestions for improving the code.     

Passivhaus as a low-energy building standard: contribution to a typology

With a rising concern for climate change, energy security and the environment, passive houses are receiving increasing interest among politicians and planners, and the concept is used and expressed in several settings to describe a type of very-low-energy building. Different approaches have arisen with several attempts to provide systems of validation of low-energy buildings. One major reference is the formalization into the German Passivhaus standard by the Passivhaus Institut in Darmstadt, which is presented as a strategy for energy efficiency. This article explores several underlying key issues, and a typology for energy in buildings is proposed and then developed for passive houses and exemplified using the Passivhaus standard. The concepts of low-energy buildings as expressed in some European standards, labels or certificates are explained and a special attention is provided to the Passivhaus standard. The final analysis shows the weakness of some approaches and the pertinence of the Passivhaus standard and invites for further research.     

Energy monitoring and conservation potential in school buildings in the C′ climatic zone of Greece

Energy efficiency is very important in school buildings as it is associated with comfort and air quality conditions in their interior and energy costs of these buildings are associated with their main operational costs. Moreover, school buildings differ from other types of buildings because they are the places where children are educated and have the opportunity to learn how to become environmentally-aware citizens. There is an increasing awareness throughout Europe for promotion of sustainable solutions in school buildings involving energy efficient technologies and measures. The aim of this article is to assess the energy performance, based on monitored data, of school buildings in the C′ climatic zone of Greece, a region with the lowest air temperature during winter period. It also demonstrates, through simulation studies, the potential for energy conservation of school buildings in this region.     

Investigating the feasibility of positive energy residential buildings in tropical climates

Positive energy residential buildings are houses that generate more energy from renewable sources than they consume while maintaining appropriate thermal comfort levels. However, their design, construction and operation present several critical challenges. In particular, the considerable load reductions are not always compatible with the increased level of comfort expected in modern houses. Tropical climates, meanwhile, should be more amenable to the implementation of positive energy houses for two reasons. Firstly, negligible heating is generally required as compared to colder climates, where the heating energy requirements are considerable. Then, renewable energy resources are usually abundant in tropical climates. This paper investigates the feasibility of positive energy residential buildings in the tropical island of Mauritius. A baseline model representing a typical Mauritian house is designed using DesignBuilder software. The energy efficiency of the model is then optimised by investigating a whole range of passive building design strategies, many of them adapted from vernacular architecture. Results reveal that the application of passive strategies such as shading, insulation and natural ventilation have precluded the need for artificial cooling and ventilation in the positive energy (PE) house. The resulting electricity consumption of the house decreases from 24.14 to 14.30 kWh/m²/year. A 1.2 kW photovoltaic system provides the most cost-effective solution to exceed the annual electricity requirements of the house.     

Building energy efficiency in rural China

Rural buildings in China now account for more than half of China's total building energy use. Forty percent of the floorspace in China is in rural villages and towns. Most of these buildings are very energy inefficient, and may struggle to provide for basic needs. They are cold in the winter, and often experience indoor air pollution from fuel use. The Chinese government plans to adopt a voluntary building energy code, or design standard, for rural homes. The goal is to build on China's success with codes in urban areas to improve efficiency and comfort in rural homes. The Chinese government recognizes rural buildings represent a major opportunity for improving national building energy efficiency. The challenges of rural China are also greater than those of urban areas in many ways because of the limited local capacity and low income levels. The Chinese government wants to expand on new programs to subsidize energy efficiency improvements in rural homes to build capacity for larger-scale improvement. This article summarizes the trends and status of rural building energy use in China. It then provides an overview of the new rural building design standard, and describes options and issues to move forward with implementation.     

A study on residential heating energy requirement and optimum insulation thickness

Heat loss from buildings has a considerable share in waste of energy especially in Turkey since no or little insulation is used in existing and new buildings. Therefore, energy savings can be obtained by determining of heat loss characteristics with using proper thickness of insulation. For this purpose, in this study, calculations of optimum insulation thickness are carried out on a prototype building in Bursa as a sample city. Considering long term and current outdoor air temperature records (from 1992 to 2005), degree-hour (DH) values are calculated, and the variation of annual energy requirement of the building is investigated for various architectural design properties (such as air infiltration rate, glazing type, and area). Then, the effects of the insulation thickness on the energy requirement and total cost are presented. Based on life cycle cost (LCC) analysis, the optimum insulation thicknesses are determined for different fuel types. As a conclusion, the length of the heating period is average 221 days, and the mean heating DH value is found as 45 113.2 besides changing between 38 000 and 55 000. The optimum insulation thicknesses for Bursa vary between 5.3 and 12.4 cm depending on fuel types. In addition to this, the variation in Turkey is more dramatically.     

Overview of rural building energy efficiency in China

Over the past three decades, people׳s living standard in China has been greatly improved, accompanied by the rapid increasing building energy consumption. Rural building energy consumption has become one of the most important parts of the total energy consumption in China, which deserves to be paid much attention. It is of vital importance to promote building energy efficiency for the New Socialist Countryside and energy conservation and emission reduction. This paper provides an overview of building energy consumption in the countryside, which figures out the situation and challenges in energy-saving work. The government has worked for years on rural building code system aimed at narrowing the energy gap between urban areas, but it is in the beginning phase. This paper has analyzed the only special issues about rural building energy efficiency and the mandatory standards for urban buildings, which can facilitate the development of rural building energy efficiency. Based on the above analysis, some recommendations regarding the improvement of rural building energy efficiency are given.     

透明热反射薄膜研究与开发——上海市能源研究所廿年研究工作的回顾

透明热反射薄膜（Transparent Heat Mirror，以下简称THM膜）是一种光谱选择性材料，在太阳能开发、建筑节能，以及家用电器等领域节能有着广泛的应用前景，上海市能源研究所（SIER）在近20年中从基础研究和材料开发等方面均进行了一些有意义的研究，现就有关该材料的基础性研究和某些方面的应用试验综述介绍。