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.     

Significance of mobility in the life-cycle assessment of buildings

While most life-cycle assessments of buildings have focused on construction and use phases, the location of a building can significantly affect the transportation demand of its inhabitants. The life-cycle energy and greenhouse gas (GHG) emissions of two representative buildings in Lisbon, Portugal, are compared: an apartment building in the city centre and a semidetached house in a suburban area. An integrated approach is used to conduct a life-cycle analysis that includes building construction, building use and user transportation. Sensitivity analyses are used to evaluate impacts for multiple locations. For the apartment, building use accounted for the largest share of energy and emissions (63–64%), while for the house, most (51–57%) of the energy and emissions were associated with user transportation. Energy and GHG emissions for suburban locations were significantly higher (by 55–115%) than those in the city-centre locations, largely due to individuals commuting by car. The analysis demonstrates the significance of transportation and highlights the importance of residence location in urban planning and environmental assessments. These results are likely to apply to other southern European cities that have expanded with significant growth in car ownership and use. To improve urban sustainability, development strategies should consider the transport infrastructure in addition to building efficiency.     

住宅建筑气候适应性优化设计研究

以中国5个典型城市的气候条件为例，提出住宅建筑气候适应性优化设计流程。基于Grasshopper参数化性能分析平台，和Ladybug/Honeybee环境分析插件，以热环境舒适度模型、建筑能耗模型和建筑生命周期成本模型为目标函数进行优化分析。发现哈尔滨和北京气候条件下，住宅建筑应选择nZEB'（权衡最优）设计参数，而上海、昆明和深圳气候条件下，C-O（成本效益最优）解决方案比nZEB（节能最优）解决方案的综合效益更好。基于参数化性能模拟的多目标优化可以有效辅助住宅建筑的气候适应性设计研究。     

Life-cycle assessment of post-disaster temporary housing

The estimation of energy consumption and related CO₂ emissions from buildings is increasingly important in life-cycle assessment (LCA) studies that have been applied in the design of more energy-efficient building construction systems and materials. This study undertakes a life-cycle energy analysis (LCEA) and life-cycle CO₂ emissions analysis (LCCO₂A) of two common types of post-disaster temporary houses constructed in Turkey. The proposed model includes building construction, operation and demolition phases to estimate total energy use and CO₂ emissions over 15- and 25-year lifespans for container houses (CH) and prefabricated houses (PH) respectively. Energy efficiency and emission parameters are defined per?m² and on a per capita basis. It is found that the operation phase is dominant in both PH and CH and contributes 86–88% of the primary energy requirements and 95–96% of CO₂ emissions. The embodied energy (EE) of the constructions accounts for 12–14% of the overall life-cycle energy consumption. The results show that life-cycle energy and emissions intensity in CH are higher than those for PH. However, this pattern is reversed when energy requirements are expressed on a per capita basis.     

European residential buildings and empirical assessment of the Hellenic building stock,energy consumption,emissions and potential energy savings

The existing building stock in European countries accounts for over 40% of final energy consumption in the European Union (EU) member states, of which residential use represents 63% of total energy consumption in the buildings sector. Consequently, an increase of building energy performance can constitute an important instrument in the efforts to alleviate the EU energy import dependency (currently at about 48%) and comply with the Kyoto Protocol to reduce carbon dioxide emissions. This is also in accordance to the European Directive (EPBD 2002/91/EC) on the energy performance of buildings, which is currently under consideration in all EU member states. This paper presents an overview of the EU residential building stock and focuses on the Hellenic buildings. It elaborates the methodology used to determine the priorities for energy conservation measures (ECMs) in Hellenic residential buildings to reduce the environmental impact from CO₂ emissions, through the implementation of a realistic and effective national action plan. A major obstacle that had to overcome was the need to make suitable assumptions for missing detailed primary data. Accordingly, a qualitative and quantitative assessment of scattered national data resulted to a realistic assessment of the existing residential building stock and energy consumption. This is the first time that this kind of aggregate data is presented on a national level. Different energy conservation scenarios and their impact on the reduction of CO₂ emissions were evaluated. Accordingly, the most effective ECMs are the insulation of external walls (33–60% energy savings), weather proofing of openings (16–21%), the installation of double-glazed windows (14–20%), the regular maintenance of central heating boilers (10–12%), and the installation of solar collectors for sanitary hot water production (50–80%).     

高能效建筑设计策略

随着国民经济的快速发展和人民生活水平的不断提高,能量消耗和温室气体排放也愈来愈高。同时,我国建筑能耗也占到总能耗的约28%。可持续建筑(绿色建筑)的不断发展对整个建筑业提出了新的要求和机遇。该文提出了以高能效设计为核心的绿色建筑设计策略。     

Inventory analysis of LCA on steel- and concrete-construction office buildings

A life-cycle inventory model for the office buildings is developed in this paper. The environmental effects of two different building structures, steel and concrete, are intercompared. The results show that the steel-framed building is superior to the concrete-framed building on the following two indexes, the life-cycle energy consumption and environmental emissions of building materials. It is found that the life-cycle energy consumption of building materials per area in the steel-framed building is 24.9% as that in the concrete-framed building, whereas, on use phase, the energy consumption and emissions of steel-framed building are both larger than those of concrete-framed building. As a result, lower energy consumption and environmental emissions are achieved by the concrete-framed building compared with the steel-framed building on the whole life cycle of building. The present study also provides a good method of assessing the performance of energy saving and environmental protection of different building structures based on a whole life cycle.     

Towards a universal energy efficiency index for buildings

The growing worldwide demand for energy is basically satisfied through natural resources such as oil or natural gas generally acknowledged as being responsible for climate change through greenhouse gas emissions. The building sector accumulates approximately a third of the final energy consumption. Consequently, the improvement of the energy efficiency in buildings has become an essential instrument in the energy policies to ensure the energy supply in the mid to long term, and to meet the targets stated in the Kyoto Protocol. During the last decade and being sensitive to this fact, many national governments and international organizations have developed new regulations to achieve those targets. One of these regulations is the European Energy Performance of Buildings Directive but, to date this certification does not follow a standard procedure which is universally accepted.This paper aims to contribute to this standardization, proposing an energy efficiency index for buildings that relates the energy consumption within a building to reference consumption. The proposed energy index can be obtained in a simple manner by combination standard measurements of energy consumption, simulation and public databases. Furthermore, the index is upgradable whenever new data are available.     

Evaluation of BIM energy performance and CO2 emissions assessment tools: a case study in warm weather

ABSTRACT

The EU members have adopted regulations and official methods for evaluating the energy performance in buildings. Most of these methods are applied at the end of the project phase, with few opportunities to correct erroneous design decisions when the desired building energy performance is not achieved. It is demonstrated that there is no European standard for sustainability and that the decision-making process during the development of a building project is compromised by the methodologies and some concepts, as thermal inertia, are withdrawn. Currently, the industry has been developing alternative tools for evaluating energy performance and CO₂ emissions in buildings over their entire life cycle. These software programs, which belong to the BIM environment, use databases and make simplifications adapted to the stage of design when the software can be applied. The main objective of this paper is to evaluate the accuracy of this software and how the databases and simplifications influence the decision-making process in building design. Calculation examples are carried out with various tools and compared to real building performance data. The results demonstrate that, as with the official methods, the tools influence the results and therefore condition, sometimes wrongly, the decision-making process to produce better buildings.     

Cost effective energy and carbon emissions optimization in building renovation (Annex 56)

The construction sector has become an important target for reducing carbon emissions and energy consumption and for kerbing resource depletion, because of its relevance in all these important areas.Many of the current energy related policies have their focus on new buildings but, due to the low rates of replacement of the existing building stock, it is crucial that the low energy performances of these buildings are improved. Most of these buildings,due to design and construction constraints,may not be able to reach the new energy efficiency standards,which many times involve complex construction works. Nevertheless, the achievement of significant reductions in energy consumption and carbon emissions may not always require a highly efficient solution for the envelope. Other solutions, combining energy efficiency measures and the use of renewable energy, are also possible.In this context, the key research problem addressed in Annex 56 was to understand how far it is possible to go with energy conservation and efficiency measures and from which point the measures to foster renewable energy use become more economical taking into account the local context and the many restrictions the existing buildings face.Thus,a new methodology was developed to be used in the decision making process for energy related building renovation, allowing to find a cost-effective balance between energy consumption,carbon emissions and overall added value achieved in the renovation process.The methodology developed within IEA EBC Annex 56 project aims at defining,assessing and comparing energy renovation activities in a cost-effective way,o ptimizing the energy use and the carbon emissions reduction,mainly in residential buildings but also in non-residential buildings without complex HVAC technologies.The methodology explores the full range of cost-effective reduction of carbon emissions and energy use and takes into account also the additional benefits and the overall added value achieved by the building within the renovation process.     

Life cycle cost implications of energy efficiency measures in new residential buildings

The importance of the built environment from an environmental impact and energy use perspective is well established. High thermal efficiency of the constructed building envelope is a key strategy in the design and construction of buildings which limit use of active space conditioning systems. Australia's current housing stock is thermally poor and national energy performance standards are relatively weak when benchmarked against international best practice. A lack of data has impeded the policy debate and a significant gap in analysis remains a lack of empirical research into the life-cycle cost implications of increased building thermal efficiency, particularly for residential buildings. This paper applies an integrated thermal modeling, life cycle costing approach to an extensive sample of dominant house designs to investigate life cycle costs in a cool temperate climate, Melbourne Victoria. Empirical analysis provides new insights into lifetime costs and environmental savings for volume housing design options and identifies sensitive factors. Results suggest that the most cost-effective building design is always more energy efficient than the current energy code requirements, for the full time-horizon considered. Findings have significant policy implications, particularly in view of present debates which frequently present higher energy efficiency standards as prohibitive from a costs perspective.     

Sun-control options in a high-rise office building

The DOE-2 building energy analysis computer program has been used to study the life-cycle cost and annual energy use for a wide range of glazing and sun-control options in a 25-story office building with 50% glazing. Four climates in the U.S. have been analyzed: Miami, Los Angeles, Washington, DC, and Chicago. The impact of daylighting in the perimeter zones for the various sun-control options has also been investigated. Double glazing was found to have little effect on energy use in Miami and Los Angeles, but reduced energy use 11–23% in Washington, DC, and 16–32% in Chicago, Daylighting reduced energy use 10–22% and had a simple payback period of 3.7–8.9 years depending on climate and type of fenestration. Of the alternatives considered, the lowest life-cycle cost and energy use were obtained with daylighting coupled with clear glazing and exterior sun-control blinds.     

影响建筑碳交易实施的关键问题分析

阐述了我国开展建筑碳排放权交易的必要性。通过对深圳市建筑能源消耗变化趋势的分析和建筑碳排放权交易机制的解读,提出开展建筑碳交易是以市场手段探索建筑节能工作的一条新路径。分析了阻碍我国碳交易试点城市实施建筑碳排放权交易的关键问题:建筑碳排放边界和建筑碳排放权交易主体的确定方法,这二者都是沿用工业企业的碳交易思路,没有体现我国建筑和建筑用能管理的实际情况。以深圳市为案例探讨了可行的应对策略和方法,提出并分析了以单栋建筑为对象采用建筑物物理边界作为建筑碳排放边界的可行性;同时提出了分阶段确定建筑碳交易主体的思路,现阶段对不同建筑类型可制定不同的交易主体,如交易对象可以是办公楼的建筑业主,酒店和商业建筑的建筑用户;而未来交易主体可以过渡为能源缴费单位。     

Life-cycle energy analysis of buildings: a case study

Energy use is a widely used measure of the environmental impact of buildings. Recent studies have highlighted the importance of both the operational and embodied energy attributable to buildings over their lifetime. The method of assessing lifetime building energy is known as life-cycle energy analysis. With Kyoto target obligations necessitating the quantification of greenhouse gas emissions at the national level, it seems increasingly probable that analyses of this kind will increase in use. If conducted in primary energy terms, such analyses directly reflect greenhouse gas emissions, except for a few processes which involve significant non-energy related emissions such as cement manufacture. A Life-Cycle Assessment would include these issues, as well as other environmental parameters, though probably with a corresponding decrease in system boundary completeness. This paper briefly explains some of the theoretical issues associated with life-cycle energy analysis and then uses an Australian based case study to demonstrate its use in evaluating alternative design strategies for an energy efficient residential building. For example, it was found that the addition of higher levels of insulation in Australia paid back its initial embodied energy in life-cycle energy terms in around 12 years. However, the saving represented less than 6% of the total embodied energy and operational energy of the building over a 100-year life cycle. This indicates that there may be other strategies worth pursuing before additional insulation. Energy efficiency and other environmental strategies should be prioritized on a life-cycle basis. La consommation d'energie est un parametre tres utilise lorsque l'on veut mesurer l'impact des batiments sur l'environnement. Des etudes conduites recemment ont mis en lumiere l'importance de l'energie operationnelle et celle de l'energie intrinseque degagees par les batiments pendant leur duree de vie. L'analyse energetique des batiments pendant leur cycle de vie est une methode d'evaluation de l'energie d'un batiment pendant sa duree de vie. Pour respecter les objectifs de la Conference de Kyoto, il faut quantifier les emissions de gaz de serre au niveau national; il semble donc de plus en plus probable que la pratique de ces analyses va aller en augmentant. Si elles portent sur l'energie primaire, ces analyses rendront parfaitement compte des emissions de gaz a effets de serre, sauf pour quelques procedes industriels, comme la fabrication du ciment, ou les emissions de ces gaz ne sont pas liees a l'energie. Toute evaluation du cycle de vie doit tenir compte de ces questions mais aussi d'autres parametres environnementaux, mais avec, sans doute, une moindre nettete des limites des systemes. Le presente communication expose brievement quelques uns des problemes theoriques lies aux analyses energetiques sur le cycle de vie et s'appuie sur une etude de cas australienne pour demontrer son utilite a evaluer d'autres strategies de conception de batiments a usage d'habitation a faible consommation d'energie. On a constate, par exemple, qu'en Australie le fait d'ajouter des niveaux d'isolation remboursait en 12 ans environ l'energie intrinseque initiale en terme d'energie sur le cycle de vie. Toutefois, les economies representaient moins de 6% de l'energie intrinseque totale et de l'energie operationnelle du batiment sur un cycle de vie de 100 ans. Cela veut dire qu'il serait peut etre interessant d'envisager d'autres strategies avant d'augmenter l'isolation. On devrait donner priorite a l'efficacite energetique et a d'autres strategies environnementales sur la base du cycle de vie.     

Renewable energy options for buildings: Case studies

This paper deals with a novel approach to study renewable energy options for buildings to make them more efficient, more cost effective, more environmentally benign, and more technologically attractive. To demonstrate the application of this study, four buildings are chosen as case studies with two from the residential sector, one commercial/institutional building, and one industrial building. A ground source heat pump for heating and cooling, a solar water heater for space heating and/or hot water, and a photovoltaic panel to generate electricity are designed for these case studies. Attempt is made to design projects under hybrid systems combined from two technologies are developed for the above-mentioned four cases. Results obtained indicate that solar thermal option for hot water and space heating becomes the most cost effective one for all cases (e.g., $4956 for Cases 1 and 2 and $70,652 for Case 3, and $91,361 for Case 4). In addition, solar electricity through PVs is technologically the most suitable one to meet the electricity demand. The ground source heat pump option is quite attractive from the efficiency and environmental impact point of views although it requires installation and maintenance, etc. Finally, hybrid systems provide better advantages, such as higher efficiency, reduced cost, reduced emissions, etc.     

Analysis of domestic hot water energy consumption in large buildings under standard conditions in Senegal

This paper presents an investigation of the energy consumption due to domestic hot water (DHW) production in large buildings. We have studied three types of reference buildings: one office, one residence and a 3-star hotel located in Senegal. The DOE2.1E (the building energy program of the Department of Energy Version 2.1E) has been used. One of its main advantage is that it allows to take into account both energy end use categories and a great number of parameters of the building energy performance. Four climatic regions have been identified and their equivalent “standard” conditions are all defined. Those conditions are the same as the current design and operating conditions of each type of building. The DHW energy consumption is calculated and compared with the total energy generated by all end uses (lighting, cooling/ventilation, DHW, and other equipment). Before we carry out wide and systematic simulations of the three buildings energy performance, we pay special attention to check and validate the DHW part of the DOE2.1E model. There was an agreement between the recorded monthly DHW energy load on the one hand, and on the other the computed results. We end up finding results that could open new perspectives for building a strategic methodology to provide guidelines for DHW energy saving measures in large buildings in West Africa. Furthermore, it is expected that energy researchers concerned about energy and environmental efficiency would consider this study for promoting CO₂ emission reduction in relation with DHW production in large buildings.     

Energy efficient design and occupant well-being: Case studies in the UK and India

The purpose of this paper is to demonstrate the relationships between sustainable building design and occupant well-being. It starts with a definition of sustainable design and well-being, and focuses on the relationships between energy performance and occupant feedback. Methodologically it draws on detailed monitoring and surveys of 12 case study office buildings in the UK and India, and the paper uses the data to explore whether energy use and associated CO₂ emissions are correlated to occupant satisfaction and comfort. The results demonstrate that increased energy use in the case study buildings is associated with increased mechanisation (e.g. centralised air conditioning) and reduced occupant control. This reduced control in turn is shown to relate to reduced occupant comfort and satisfaction. Finally, the paper reveals that the reported health conditions of occupants correlates strongly with their levels of satisfaction. The overall conclusion is that energy use in typical office buildings is inversely correlated with the well-being of the occupants: more energy use does not improve well-being.     

既有公共建筑节能改造的全寿命周期费用研究

以既有公共建筑为研究对象,采用全寿命周期费用分析的方法,分析出所发生的四大费用:改造费用,使用费用,拆除费用和政府的补贴,以及详细的费用构成,建立了节能改造的LCC估算模型。详细介绍了既有公共建筑节能改造全寿命周期费用中节约费用的计算方法,并且引入碳排放权交易理论,运用碳交易价格确定出公共建筑节能改造后,每年可以节约的费用,不仅可以更好地衡量出节能改造的经济效果和减排效果,而且为我国进入国际碳交易市场打下基础。     

Using dynamic simulation to quantify the effect of carbon-saving measures for a UK supermarket

A standard UK supermarket design is used to simulate the energy performance, and subsequent CO₂ emissions, of a modern-day UK supermarket building. Retrofit measures are proposed to reduce these CO₂ emissions by over 50%, mostly due to demand-side measures but also accounting for likely onsite supply-side solutions. The influence of refrigeration and lighting in such buildings is explored and the possible use of heat recovery systems discussed. The air-tightness of supermarket buildings is also highlighted as a potential area for significant energy savings. Finally, the reliance on grid electricity is demonstrated for non-domestic buildings with a high electrical energy use. A combined approach of energy efficiency and low-carbon offsite electrical generation is suggested from the described case study as the most successful strategy to achieve large carbon savings (i.e. >50%) in existing supermarket buildings.     

Greenhouse gas emissions in building construction: A case study of One Peking in Hong Kong

The construction of buildings has a very important impact on the environment, and the process of manufacturing and transporting of building materials, and installing and constructing of buildings consumes great energy and emits large quantity of greenhouse gas (GHG). The present paper defines four sources of GHG emissions in building construction, which are: manufacture and transportation of building materials; energy consumption of construction equipment; energy consumption for processing resources; and disposal of construction waste, and then establishes the calculation method of GHG emissions. This paper presents a case study of GHG emissions in building construction in Hong Kong. The results show that 82–87% of the total GHG emissions are from the embodied GHG emissions of building materials, 6–8% are from the transportation of building materials, and 6–9% are due to the energy consumption of construction equipment. The results also indicate that embodied GHG emissions of concrete and reinforced steel account for 94–95% of those of all building materials, and thus the use of recycled building materials, especially reinforced steel, would decrease the GHG emissions by a considerable amount.