Climate change adaptation pathways for Australian residential buildings

Climate change can significantly impact on the total energy consumption and greenhouse gas (GHG) emissions of residential buildings. Therefore, climate adaptation should be properly considered in both building design and operation stages to reduce the impact. This paper identified the potential adaptation pathways for existing and new residential buildings, by enhancing their adaptive capacity to accommodate the impact and maintain total energy consumption and GHG emissions no more than the current level in the period of their service life. The feasibility of adaptations was demonstrated by building energy simulations using both representative existing and new housing in eight climate zones varying from cold, temperate to hot humid in Australia. It was found that, in heating dominated climates, a proper level of adaptive capacity of residential buildings could be achieved simply by improving the energy efficiency of building envelop. However, in cooling dominated regions, it could only be achieved by introducing additional measures, such as the use of high energy efficient (EE) appliances and the adoption of renewable energy. The initial costs to implement the adaptations were assessed, suggesting that it is more cost-effective to accommodate future climate change impacts for existing and new houses by improving building envelop energy efficiency in cooling dominated regions, but installing on-site solar PVs instead in heating and cooling balanced regions.     

Analysis of the thermal behaviour of a low cost,single-family,more sustainable house in Porto Alegre,Brazil

Efforts have been made in Brazil to improve the thermal performance of low-cost buildings. Since 1997 studies on low-cost housing have been developed by Núcleo Orientado para a Inovação da Edificação, the construction sector of the Engineering College of the Rio Grande do Sul University, Brazil. In 2000 a prototype of a low-cost house was built on the university campus. This prototype has undergone several evaluations in an attempt to assess its thermal and environmental performance, like: energy consumption, rainwater harvesting, use of sustainably managed wood for window frames and doors, besides a detailed accounting of overall costs. The thermal performance of the house was monitored, by recording outdoor and indoor air temperatures and relative humidity, over the period of whole year. A brief appraisal of such results, as well as the annual heating and cooling degree-hours are presented. Daily swings in outdoor are a common climatic event in Porto Alegre and the building response to daily temperature swings, greater than 10 K, and hot and cold spells are presented. The results show that the thermal performance of the prototype is fairly satisfactory, considering the limitations of a low-cost house, when artificial heating and cooling is not affordable.     

Theoretical and experimental thermal performance assessment of an innovative external wall insulation system for social housing retrofit

The UK building stock,being amongst the oldest in the developed world,is also one of the least energy efficient and accounts for approximately 45% of UK carbon emission. Energy use from housing alone was responsible for 13% of total UK carbon dioxide and greenhouse gas emissions in 2015. Therefore,achieving the national target of an 80% reduction in carbon emissions by 2050 against 1990 baseline conditions is highly dependent on the reduction of energy consumption in dw ellings. The complexity of the problem of retrofitting energy saving measures in the extensive and diverse aging housing stock is further compounded due to the number of "hard to treat " properties that comprise over 40% of homes in the UK. In this article,the authors present an evaluation of the theoretical and experimental performances of a novel prototype external wall insulation system,developed to improve energy efficiency in "hard to treat"housing. The system was designed to be primarily used to retrofit social housing,w hich comprises up to 18% of the current UK housing stock.A thorough testing regime was undertaken to test the suitability and effectiveness of the new product in the most common social housing construction typologies. This included: an investigation of the theoretical thermal performance of the prototype product through steady state modelling,a laboratory based prototype test,an analysis of empirical data collected from a cross section of social housing properties in Nottinghamshire,UK used to inform whole house dynamic modelling,and the development of dynamic simulations to assess the energy and carbon reduction impacts of the new product. The theoretical modelling suggested that the integration of the system resulted in thermal performance improvements for all construction types with space heating demand reduced by up to 42%. The results of the whole house dynamic modelling assessment also suggested that the addition of the system resulted in a reduction of heating energy demand of up to 49%. The prototyping testing show n that the system is easy to install requirement minimum building skills.The findings suggest that the new product not only meets the performance of existing external wall insulation systems,but also provides unique selling points with respect to easy installation and non-reliance on weather conditions. The project finished with a pilot study when one house was retrofitted using the novel product.     

Occupants have little influence on the overall energy consumption in district heated apartment buildings

The purpose of this research is twofold: first, to evaluate how occupant behavior in a neutral environment influences the overall greenhouse gas emissions and energy consumption of multi-family apartment buildings, and second: to establish which activities associated with housing companies produce the most greenhouse gas emissions. The research comprised of a multiple cases of housing companies dating from the late 1960s and located in the Finnish capital Helsinki. The studied housing companies represent the least energy efficient third of the Finnish residential building stock, approaching obligatory large scale refurbishments. The analysis is conducted in two phases with a so called hybrid life-cycle assessment (LCA) technique. Using the technique, both economic and metric consumption data are analyzed to estimate the greenhouse gas emissions generated by activities associated with housing. In line with previous research, the study identifies heating energy as the single most significant contributor to greenhouse gas emissions. The results also show that the carbon load associated with housing activities makes up one third of an individual resident's overall carbon footprint. Contrary to often stated belief, the study indicates that occupant behavior has only limited effect on the energy consumption and, consequently, carbon emissions derived from housing, particularly when multi-family housing connected to district heating is concerned. However, apartment size seems to have a two-way impact, the smallest and the largest being the least energy efficient.     

Mitigating temperature increases in high lot density sub-tropical residential developments

Residential developments built with houses that use passive design features can have significantly reduced energy requirements for thermal comfort. In the context of global warming, this can reduce greenhouse gas emissions. The current trend towards higher lot density in residential developments and the resulting increase in thermal mass increases the associated heat island effect. Designers of future residential developments face the dual challenges of heat island impacts and any future global warming. Resource efficient house designs combined with approaches that mitigate the outdoor heat load must be considered and addressed from the design of the initial subdivision layout. Some land sub-division and house design initiatives are proposed for sub-tropical climatic conditions as prevailing in south-east Queensland, Australia. Computer simulations that account for heat island and global warming effects are used to estimate the indoor thermal performance of display houses constructed by a large scale property developer for current climate conditions and scenarios that may occur in the future. The use of north–south orientation of narrow building lots combined with high albedo house surfaces and the increased strategic use of shade trees for reducing the heat island effect of high density residential developments are presented. The cooling requirements of houses with high-energy rating (5 star or more) are found to be significantly superior to those with low rating (3.5 star) in scenarios of global warming.     

Addressing climate change in comfort standards

According to the Buildings Energy Data Book published by the U.S. Department of Energy, in 2006 the building sector consumed 38.9% of the total primary energy used in the United States. Of this energy, 34.8% is used by buildings for space heating, ventilation, and air conditioning. This energy often involves the combustion of fossil fuels, contributing to carbon dioxide emissions and climate change. Even if greenhouse gas concentrations are stabilized in the atmosphere, extreme climate events and sea level rise will continue for several centuries due to inertia of the atmosphere. Therefore, adaptation will be a necessary compliment to carbon dioxide mitigation efforts. This paper argues that both mitigation of greenhouse gases and adaptation to climate change should be added to our building codes and standards. Since space heating, ventilation, and air-conditioning utilize a large amount of energy in buildings, we should begin by redefining our thermal comfort standards and add strategies that mitigate carbon dioxide emissions and adapt to predicted climate variability.     

Comparison of environmental impacts of two residential heating systems

This paper presents a comparison of environmental impacts of two residential heating systems, a hot water heating (HWH) system with mechanical ventilation and a forced air heating (FAH) system. These two systems are designed for a house recently built near Montreal, Canada. The comparison is made with respect to the life-cycle energy use, the life-cycle greenhouse gas (GHG) emissions, the expanded cumulative exergy consumption (ECExC), the energy and exergy efficiencies, and the life-cycle cost. The results indicate that the heating systems cause marginal impacts compared with the entire house in the pre-operating phase. In the operating phase, on the other hand, they cause significant environmental impacts. The HWH systems with a heat recovery ventilator (HRV) using either electricity or natural gas have the lowest life-cycle energy use and lowest ECExC. The HWH and FAH systems using electricity as energy source have the lowest GHG emissions. Finally, the FAH systems have, on the average, a lower life-cycle cost than the HWH systems.     

Transport,Housing and Urban Form: The Life Cycle Energy Consumption and Emissions of City Centre Apartments Compared with Suburban Dwellings

Buildings in cities and the activities carried out therein use a significant proportion of a nation's energy consumption and produce substantial quantities of greenhouse gases in the process. Residential buildings are a large contributor, partially as a result of the transport and housing activities of households. In this study, life cycle analysis is used to calculate the total transport and housing energy and emissions from a sample of 41 households in apartment buildings in the city centre of Adelaide, Australia and compare them with suburban households. The purpose of this is to determine whether the urban density option of higher rise dwellings offers a lower environmental impact than conventional housing. The analysis includes delivered energy and greenhouse gas emissions generated by motorised travel and activities within the dwellings, and the energy and emissions embodied in household motor vehicles and the apartment buildings. The total delivered energy consumption of apartment households was found to be lower than suburban households due mainly to higher car usage, particularly in the outer suburbs. However, the analysis of total greenhouse gas emissions provided a somewhat different comparison especially when they were considered on a per capita basis. The total per capita emissions for apartment households varied considerably but, on average, exceeded those of both the inner and outer suburban households. This resulted from lower occupancy rates and higher emissions arising from higher dwelling operational and embodied energy consumption. Overall, it cannot be assumed that centralised, higher density living will deliver per capita emission reductions for residents, once the combined per capita life cycle emissions from housing and transport have been accounted for. A more vigorous educational, promotional and regulatory approach is required to achieve greater operational and embodied energy efficiency in apartment buildings to fully realise the emissions-reducing potential of such buildings in centralised locations.

     

公共建筑冬夏季累计评价法真空玻璃窗节能效果分析

将冬季和夏季门窗的逐时得热进行累积,得到采暖季和空调季的热工性能计算公式,进而对门窗的节能效果进行评价。针对同一公共建筑模型,分别选用真空玻璃铝合金窗替代单片白玻铝合金窗、普通中空玻璃铝合金窗和Low—E中空玻璃铝合金窗,按计算公式得到哈尔滨、北京、上海和广州地区和四个朝向窗户全年的累积得热值、节能率、节约能耗总量、节省的能源成本及污染物和温室气体排放量。     

Parametric study on the performance of green residential buildings in China

The parametric study of the indoor environment of green buildings focuses on the quantitative and qualitative improvement of residential building construction in China and the achievement of indoor thermal comfort at a low level of energy use. This study examines the effect of the adaptive thermal comfort of indoor environment control in hot summer and cold winter (HSCW) zones. This work is based on a field study of the regional thermal assessment of two typical cases, the results of which are compared with simulated results of various scenarios of “energy efficiency” strategy and “healthy housing” environmental control. First, the simulated results show that the adaptive thermal comfort of indoor environment control is actually balanced in terms of occupancy, comfort, and energy efficiency. Second, adaptive thermal comfort control can save more energy for heating or cooling than other current healthy housing environmental controls in China's HSCW zone. Moreover, a large proportion of energy use is based on the subjective thermal comfort demand of occupants in any building type. Third, the building shape coefficient cannot dominate energy savings. The ratio of the superficial area of a building to the actual indoor floor area has a significant positive correlation with and affects the efficiency of building thermal performance.     

Evaluation of energy efficient design strategies for different climatic zones: Comparison of thermal performance of buildings in temperate-humid and hot-dry climate

Since the Kyoto protocol signed in December 1997 the majority of governments around the world have committed themselves to reducing the emission of the greenhouse gases. Thus, efficient use of energy and sustainability has become a key issue for the most energy policies. Sustainability and energy saving terms take place in building construction industry too since buildings are one of the most significant energy consumers. It is known that heating energy demand of a building has a great rate in building total energy consumption. In addition to that, the most of the heating energy has been lost from building envelope. TS 825, Heating Energy Conservation Standard for Buildings in Turkey, aims the reducing of heat loss in buildings through the envelope. But within buildings, one of the fastest growing sources of new energy demand is cooling and especially in hot-humid and hot-dry climatic parts of Turkey cooling season is much longer than the heating season. Moreover in hot-dry climate heat storage capacity of the envelope becomes more important issue than heat insulation for energy efficiency of the building. Since the Turkish standard is considering only heating energy conservation by using degree-day concept, Istanbul and Mardin are considered in the same zone, however those are in temperate-humid and hot-dry climatic zones, respectively. In this study energy efficient design strategies for these climatic zones have been explained and thermal performance of two buildings, which are constructed according to the TS 825 in Mardin and Istanbul cities were evaluated to show the importance of thermal mass in hot-dry climates.     

A comprehensive life cycle water analysis framework for residential buildings

Most studies on the environmental performance of buildings focus on energy demand and associated greenhouse gas emissions. They often neglect to consider the range of other resource demands and environmental impacts associated with buildings, including water. Studies that assess water use in buildings typically consider only operational water, which excludes the embodied water in building materials or the water associated with the mobility of building occupants. A new framework is presented that quantifies water requirements at the building scale (i.e. the embodied and operational water of the building as well as its maintenance and refurbishment) and at the city scale (i.e. the embodied water of nearby infrastructures such as roads, gas distribution and others) and the transport-related indirect water use of building occupants. A case study house located in Melbourne, Australia, is analysed using the new framework. The results show that each of the embodied, operational and transport requirements is nearly equally important. By integrating these three water requirements, the developed framework provides architects, building designers, planners and decision-makers with a powerful means to understand and effectively reduce the overall water use and associated environmental impacts of residential buildings.     

中国被动房外围护系统研究——以寒冷、严寒气候区被动房项目为例

德国的被动房是目前世界公认的具有超低能耗、超低碳排放量、超高室内舒适度等特点的建筑技术体系。德国的气候特征与中国华北地区的气候特征具有相似性,因此,研究并建造被动房对于我国建筑节能工作的发展具有重大的意义。外围护系统作为被动房设计的重点要素,对建筑的节能效率有重大的影响。以寒冷、严寒气候区的被动房项目为例,对被动房外围护系统进行分析与阐述,并以秦皇岛"在水一方"被动式住宅示范项目为例,进行能耗模拟与对比分析。提出适合我国寒冷、严寒气候区气候特点的被动式超低能耗建筑外围护系统的设计策略。     

Micro-generation technology assessment for housing technology

Micro-generation is defined as a notion of simultaneous generation of both heat and power in an individual dwelling. It offers an elegant and economically viable way to meet the residential power/thermal loads and Kyoto targets by demonstrating superior environmental performance with high efficiency and low harmful greenhouse gas emissions. However, before introducing micro-generation systems in large quantities a number of issues should be resolved in terms of system integration, interconnect, reliability and safety.Two demonstration houses were built at the Canadian Centre for Housing Technology that have the capability of assessing different energy and building technologies under real-life conditions. A project was initiated involving a consortia of Canadian electric and gas utilities, Canadian Government agencies and Canadian fuel cell manufacturers to modify one of two existing research houses and to integrate a prototype micro-generation unit in it that would provide electricity and heat to the house, and supply surplus electricity back to the grid. The key research objectives were assessment of building integration, micro-generation system design issues and system performance characteristics. A Stirling engine micro-generation unit, fuelled by natural gas, was used for this demonstration. The unit had an electrical output of 736 W_e and a thermal output of 6.5 kW_th. The Stirling engine was connected in parallel to the grid and the residual heat from the engine was utilized through a specifically designed heat utilization module.The paper discusses the micro-generation system performance in two different setups and scenarios that were tested over the 2003 winter/spring seasons. Data showed that the micro-generation unit was able to satisfy all of the space and water heating loads to the house during the testing period. The unit provided a considerable percentage of the house’s electrical requirement, and even exported, in a few instances, some electricity back to the grid.     

Energy simulation for a high-rise building using IDA ICE: Investigations in different climates

In this paper a model of a high-rise building is constructed in the simulation program IDA ICE. The model is based on an IFC-model of a demonstration building constructed in Ljubljana, Slovenia, as part of an EU-project, EE-high-rise. The model’s energy performance was simulated for four cities: Umeå (Scandinavia), Ljubljana (Central Europe), Sibenik (Mediterranean) and Dubai (The Persian Gulf). Furthermore, the climate envelope of the building was modified with the aim to improve the model’s energy performance in each of the regions. The results were evaluated according to the energy requirements of passive house standard by the German Passive House Institute. The analysis suggests that the reference building model, which itself incorporates several energy efficient components, was unable to meet the German passive house standard in none of the four cities (Umeå, Ljubljana, Sibenik and Dubai) studied. By providing a combination of energy saving measures, such as modifications of thermal resistance of building envelope, the building may be able to meet the passive house standard in Ljubljana. The analysis concludes that the reduction in window area results in reduction of both heating and cooling demand. Increase in the thickness of the insulation and the thermal resistance of windows reduces the space heating demand for Umeå, Ljubljana and Sibenik (not applied for Dubai) while increasing the cooling demand for these cities. Increased airtightness has marginal effect on heating and cooling demand for all investigated cities. Reduced thermal resistance of windows will decrease cooling demand for Ljubljana, Sibenik and Dubai (not applied for Umeå). Reduced insulation thickness (not applied for Umeå) will decrease cooling demand for Ljubljana and Sibenik but not for Dubai. Reducing the insulation thickness may often result in reduced cooling demand for moderately warm countries since the average outdoor temperature could be lower than the indoor temperature during part of the cooling season. In those situations a reduced insulation thickness can cause heat flow from the relatively hot inside to the colder outside. However, for hot climates like in Dubai where outdoor temperature is higher than the indoor temperature for most of the year, reducing the insulation thickness will increase the cooling demand. This result suggests that the insulation thickness must be chosen and optimized based on heating and cooling demand, internal heat gain, and outdoor climate     

Impacts of airtightening retrofits on ventilation rates and energy consumption in a manufactured home

A retrofit study was conducted in an unoccupied manufactured house to investigate the impacts of airtightening on ventilation rates and energy consumption. This paper describes the retrofits and the results of the pre- and post-retrofit assessment of building airtightness, ventilation, and energy use. Building envelope and air distribution systems airtightness were measured using fan pressurization. Air change rates were measured continuously using the tracer gas decay technique. Energy consumption associated with heating and cooling was monitored through measurement of gas consumption by the forced-air furnace for heating and electricity use by the air-conditioning system for cooling. The results of the study show that the retrofits reduced building envelope leakage by about 18% and duct leakage by about 80%. The reduction in the house infiltration rates depended on weather conditions and the manner in which the heating and cooling system was controlled, but in general these rates were reduced by about one third. The energy consumption of the house for heating and cooling was reduced by only about 10%, which is relatively small but not totally unexpected given that infiltration only accounts for a portion of the heating and cooling load.     

Calculation of the yearly energy performance of heating systems based on the European Building Energy Directive and related CEN standards

According to the Energy Performance of Buildings Directive (EPBD) all new European buildings (residential, commercial, industrial, etc.) must since 2006 have an energy declaration based on the calculated energy performance of the building, including heating, ventilating, cooling and lighting systems. This energy declaration must refer to the primary energy or CO₂ emissions.The European Organization for Standardization (CEN) has prepared a series of standards for energy performance calculations for buildings and systems. This paper presents related standards for heating systems. The relevant CEN-standards are presented and a sample calculation of energy performance is made for a small single family house, an office building and an industrial building in three different geographical locations: Stockholm, Brussels, and Venice.The additional heat losses from heating systems can be 10-20% of the building energy demand. The additional loss depends on the type of heat emitter, type of control, pump and boiler.     

成都地区太阳能与燃气锅炉耦合系统的节能研究

本研究以成都地区某住宅热水系统为例,应用了一种太阳能辅助燃气锅炉供热水的系统。通过TRNSYS软件模拟分析了该系统的燃气消耗量、水泵能耗以及相应的温室气体排放量。结果表明,在保证相同温度热水输出的情况下,应用太阳能集热器辅助加热燃气锅炉可以明显地减少燃气消耗量;在此基础上,可以相应地减少CO2等温室气体的排放,得出了该耦合系统具有明显节能效益和较好的减排效益。     

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.     

Life cycle assessment of residential heating and cooling systems in four regions in the United States

Heating and cooling systems consume the most energy and are the largest source of emissions in the entire life cycle of a house. This study compares the life cycle impacts of three residential heating and cooling systems—warm-air furnace and air-conditioner, hot water boiler and air-conditioner, and air–air heat pump over a 35-year study period. Simulation and life cycle assessment studies of the systems at four locations in the United States, namely Minnesota, Oregon, Pennsylvania and Texas determine the effect of regional variations in climate, energy mix, and the standard building characteristics on the systems’ environmental impacts.