Residential Buildings In Australia Research Articles

Cost Benefits of Net Zero Energy Homes in Australia

This paper presents a systematic analysis of energy savings and cost benefits associated with several options for integrating energy efficiency and renewable energy technologies. The primary goal of this study is to assess the cost-effectiveness of achieving optimal net-zero energy (NZE) designs for residential buildings in Australia. Specifically, the analysis combines a series of sensitivity analyses and multi-objective optimizations to account for a wide range of design strategies for detached homes in four cities representing different Australian climates. The results indicate that not only are NZE designs technically feasible for all the considered Australian cities, but they are also highly cost-effective. This cost-effectiveness is attributed to the lower installation costs of rooftop PV systems as well as the beneficial interactive effects of proven energy efficiency strategies. Indeed, it is found that the deployment costs of rooftop PV systems can be recovered in less than 4 years. Moreover, the addition of thermal insulation in walls and ceilings can reduce both HVAC capacities and annual energy end-use by up to 59%. Based on an optimization-based design, NZE homes in Australia can have lower construction costs and, ultimately, lower life cycle costs than dwellings built to meet current energy efficiency standards based primarily on stringent building envelope thermal performance.

Embodied Carbon in Australian Residential Houses: A Preliminary Study

Embodied carbon is a buzzword in the construction industry. Australia is committed to achieving Net Zero 2050 targets, and minimizing embodied carbon (EC) is inevitable. Owing to the population growth, there will be a significant demand for residential construction. Therefore, the material consumption in residential construction should be evaluated and proper strategies should be in place to minimize EC. The aim of this research is to undertake a preliminary study of EC in the Australian residential sector, with an emphasis on new residential home construction. This research presents a preliminary study on EC in residential buildings in Australia. Three case study residential buildings were used in this study. All three case studies are single -story residential units, with a gross floor area between 200 and 240 m2. One Click LCA software was used to calculate the EC. The EC of three case study residential homes is between 193 and 233 kgCO2e/m2. Based on the findings of this study, ‘other structures and materials’ contribute to a large amount of EC in residential construction. Concrete and aluminum are considered significant contributors to EC. Therefore, it is vital to either introduce low-EC material to replace aluminum windows or introduce various design options to minimize the use of aluminum in windows. There are various sustainable concretes available with low EC. It is essential to explore these low-EC concretes in residential homes as well. This research identifies the importance of adopting strategies to reduce the carbon impact from other sources, including concrete. It is also essential to consider the EC through transportation related to construction and promote locally sourced building materials in residential construction. Therefore, the results of this research indicate the necessity of reducing raw material consumption in Australian residential construction by implementing approaches such as a circular economy in order to circulate building materials throughout the construction supply chain and reduce raw material extraction.

Roof integrated photovoltaic for electric vehicle charging towards net zero residential buildings in Australia

The residential building sector & transportation sector has received significant attention in recent years due to carbon emissions affecting the livelihoods of humans. Electric vehicles (EVs) are poised to play a vital role in reducing dependency on non-renewable fuels and the transportation sector's environmental implications. Building integrated Photovoltaics (BIPV), on the other hand, will be able to cut down the energy requirements and contribute to building sustainability. This paper evaluates the energy, economic, and environmental performances of BIPV with EV charging system systems for a building in Canberra, Australia. BIPV with EV charging can assist in fulfilling building energy needs, charging electric vehicles, and reducing grid reliance. Different load scenarios were studied to optimize system size. Different panel layouts with orientation have been studied for the 5.0kWp BIPV system, each module rating 355kWp. The annual energy output of the BIPV system was found to vary between 8.56 MWh for layout one and 7.08MWh for layout 3. It was found that the payback back of the proposed BIPV system is 4.46 years, LCOE of 0.074AUD/kWh and EV charging cost of 0.95AUD/100 km. The BIPV with EV charging system could save approximately 160,198 kgCO2e in GHG emissions over its lifespan.

Feasibility of net zero energy high rise apartment buildings in Australia

Net-Zero Energy (NZE) buildings are gaining popularity globally as a solution to reduce operational energy usage and limit greenhouse gas emissions in the building industry. Their deployment is occurring rapidly as many countries are planning to make it mandatory for new developments. Despite the advancements in research in the various aspects of NZE, significant barriers do exist to its successful adoption and implementation, particularly with respect to high-rise residential buildings which are becoming a major portion of the housing supply in Australia. One of the challenges attributed to the achievement of NZEB performance is the uncertainty involved in selecting appropriate solution strategies that could deliver quality performances. This paper investigated strategies that can deliver NZE performance for high-rise residential buildings in Australia. A calibrated model of 26 storey high-rise apartment building with 396 units was prepared for detailed analysis of NZE strategies using building simulation. The impact of various interventions was evaluated across cities in five climate zones in Australia and a guideline for solution sets that can deliver the goal for each climate zone is presented. The findings show that NZE performance for high-rise residential buildings can be realised in Australia, albeit with some limitations. While the tropical, subtropical and cold temperate climates appear to be more challenging, proper design and optimisation of the envelope proved to be effective in overcoming the challenges imposed by the more demanding climates. The impacts of shading from neighbouring buildings and objects presented the largest impediment to energy production through the façade.

Life cycle performance of Cross Laminated Timber mid-rise residential buildings in Australia

Engineering wood products have significant potential as a sustainable alternative for concrete and steel in construction. Cross Laminated Timber (CLT) can add value to conventional timber products due to its high strength-to-weight ratio, simple installation, aesthetic features and environmental benefits. Recent changes in the national construction code permit structural timber buildings with a height of up to 25m, which demonstrates the strong commitment of the construction industry to adopt more sustainable practices. This paper aims to compare life cycle greenhouse gas emissions (LCGHGE) and life cycle cost (LCC) of CLT and reinforced concrete (RC) in identical midrise residential buildings in three most populated cities in Australia. It has shown that the CLT building has 30 % less LCGHGE compared with the RC building over a life span of 50 years in Melbourne, and 34% and 29% reduction in LCGHCE in Sydney and Brisbane, respectively. The results from LCC analysis showed that CLT building is 1.3% lower than conventional RC in Melbourne, and 0.9% lower in Sydney and Brisbane. The initial and end of life phases reflected reductions in LCGHGE and LCC for the CLT building whilst the operation phase incurred higher values. The extended service life of buildings has a major impact on the operational phase while changes in the discount rate have strong effects on the lifecycle operational and maintenance costs. Overall the CLT building outperformed the RC building in terms of LCGHGE and LCC across three cities. However, further savings in the operational phase with energy efficient methodologies and reuse or recycling of timber products at the end of life of the building can reinforce CLT as a sustainable alternative to RC construction.

Comparative life-cycle cost and GHG emission analysis of five different water heating systems for residential buildings in Australia

In this paper, five different types of water heating systems namely electric instantaneous, electric storage, natural gas instantaneous, natural gas storage, and heat pump are studied for Australian conditions. The study is carried out for understanding the life cycle cost of each system under similar water demand conditions. The focus is made on life-cycle cost (LCC) that include the running costs on an annual basis, and total running cost for the system life, maintenance cost; and greenhouse gas (GHG) emissions. The observations reveal that five systems had major differences in the upfront cost, running cost, and life-cycle cost, and GHG emissions. The observed LCC and GHG emissions for electric instantaneous, electric storage, natural gas instantaneous, natural gas storage, and heat pump are 9005 AU$, 12,724 AU$, 6955 AU$, 7479 AU$, and 8098 AU$, and 1862 tons of CO2, 2306 tons of CO2, 851 tons of CO2, 917 tons of CO2, and 842 tons of CO2 respectively.

Assessment of Natural Ventilation Potential for Residential Buildings across Different Climate Zones in Australia

In this study, the natural ventilation potential of residential buildings was numerically investigated based on a typical single-story house in the three most populous climate zones in Australia. Simulations using the commercial simulation software TRNSYS (Transient System Simulation Tool) were performed for all seasons in three representative cities, i.e., Darwin for the hot humid summer and warm winter zone, Sydney for the mild temperate zone, and Melbourne for the cool temperate zone. A natural ventilation control strategy was generated by the rule-based decision-tree method based on the local climates. Natural ventilation hour (NVH) and satisfied natural ventilation hour (SNVH) were employed to evaluate the potential of natural ventilation in each city considering local climate and local indoor thermal comfort requirements, respectively. The numerical results revealed that natural ventilation potential was related to the local climate. The greatest natural ventilation potential for the case study building was observed in Darwin with an annual 4141 SNVH out of 4728 NVH, while the least natural ventilation potential was found in the Melbourne case. Moreover, summer and transition seasons (spring and autumn) were found to be the optimal periods to sustain indoor thermal comfort by utilising natural ventilation in Sydney and Melbourne. By contrast, natural ventilation was found applicable over the whole year in Darwin. In addition, the indoor operative temperature results demonstrated that indoor thermal comfort can be maintained only by utilising natural ventilation for all cases during the whole year, except for the non-natural ventilation periods in summer in Darwin and winter in Melbourne. These findings could improve the understanding of natural ventilation potential in different climates, and are beneficial for the climate-conscious design of residential buildings in Australia.

Energy efficiency within mid-rise residential buildings: A critical review of regulations in Australia

Abstract: Within Australia, increasingly more people are choosing to live in cities. Due to a need for urban densification and more affordable housing, for the first time, development approvals for multi-residential developments have overtaken those for individual houses. The growing sector of mid-rise residential buildings in Australian cities has the potential to contribute significantly to improving the energy efficiency of the building stock. However, there is limited empirical research on this sector within the Australian context. The mandatory framework for the energy efficiency of mid-rise residential developments in Australia, with a focus on New South Wales with its distinct regulatory requirements, is critically reviewed and synthesised with the literature. The review provides an understanding of the regulatory context under which mid-rise residential developments are undertaken. The limitations of the current energy efficiency framework are highlighted. This study provides an understanding of the status quo in energy efficiency regulations for mid-rise residential buildings in Australia and demonstrates that there is both scope and an imperative for regulatory minima to be enhanced.

The NatHERS dataset: An exploration of its content, provenance, and usefulness in the characterization of new residential building

Abstract: New residential buildings in Australia must demonstrate compliance with the energy efficiency provisions of the National Construction Code (NCC) in order to gain a building permit. 71% of new residential buildings demonstrate compliance by using a Nationwide House Energy Rating Scheme (NatHERS) accredited software tool. The data collected and generated by these tools have the potential to provide valuable insights into Australia’s residential building industry, giving advance knowledge of not only the number of planned builds and their energy efficiency, but also planned construction material types and quantities. The data would be of value to government departments, construction companies, the real estate industry, energy distributors, and researchers. This paper describes the content and provenance of this dataset, explores how it might be used to characterise new residential building stock, and presents sample data and analysis.

Life-cycle cost analysis of green-building implementation using timber applications

Green buildings are gaining popularity in Australia with the applications of Green Star rating scheme. However, the credit for using timber materials in the rating scheme, while timber being a significantly used material in the fast growing residential construction industry, does not adequately guide designers and builders on the selection of the best timber types for residential applications from the life cycle perspective. This research presents the analysis on the life cycle cost of timber materials in their various applications for residential buildings in Australia and thereby provides guidance on how to best meet the requirement set out in the timber credit in the Green Start rating scheme. Structured interviews were used to collect the data on the cost of timber materials in their lifetime from builders, tradesmen and other residential construction professionals. Three sets of cost information were received under each application, for the individual timber species against three conditions (low, medium and extreme weather) with reference to residential buildings. Based on life cycle cost analysis results, the most suitable timbers for different applications are recommended.

An Evolutionary Approach to Single-sided Ventilated Façade Design

A significant portion of the carbon and greenhouse gas emissions of residential buildings in Australia is associated with energy consumption for comfort and health. This study aims to reduce the carbon emissions of residential buildings by optimizing façade design. Targeting to minimize thermal loads, mechanical ventilation will be substituted by natural ventilation, meanwhile indoor environments and appropriate visual comfort will be improved. An evolutionary approach based on a Genetic Algorithm (GA) is developed to determine a set of optimal solutions of façade design for the performance targets of ventilation efficiency, energy consumption, and visual comfort. The proposed approach comprises: an evolutionary process model; the genetic representation of single-sided façade design; genetic operation methods; and fitness functions of multi-objective performance targets as well as Pareto evaluations. The process model enables mapping of façade design options and performance targets to evolve over time. Ventilation, energy and comfort analysis of single-sided ventilation are conducted for the evaluation of the resulting performance of façade design. The expected research outcomes will improve low carbon façade design of residential buildings while reducing cooling and heating costs for the construction industry and the consumer.

Net-zero emission residential building in temperate weather condition

Residential load consumes a significant amount of grid energy for electrical and heating or cooling application. Greenhouse gas (GHG) emission or equivalent CO2 emission is the direct or indirect effect from either form of these energy uses. Energy demand is increasing with the addition of various new home appliances and energy price is also going up. Various initiatives can be taken to reduce energy demand. However the best way is by improving energy efficiency and that eventually reduces the emission. Using renewable energy (RE) to support local load demand is another approach to reduce CO2 emission. However effective use of RE depends on the climatic condition and synchronization of load-demand and local generation. Although unmatched energy from local RE generation can be sold back to the grid, the same amount of energy has to be purchased from the grid at higher cost. When the overall total amount of GHG emission in a year can be balanced by improving energy efficiency and by increasing local RE generation the condition of the house can be termed as zero emission house. This paper investigates the possibility of net-zero emission house in temperate weather condition in Geelong, Australia considering the cost of all relevant components. It was found that net-zero emission building can be implemented and can effectively reduce a total of 44 Mt of CO2 emission in a year from all 9 million residential buildings in Australia.

Comfort-based performance assessment methodology for low energy residential buildings in Australia

In Australia, the primary method of demonstrating compliance with the mandatory dwelling Energy Efficiency requirements of the National Construction Code (NCC), NatHERS, has been criticised as being unsuitable for assessing low energy houses that are intended to use little or no heating and/or cooling in operation. In 2013–2014, a longitudinal thermal comfort study was conducted in 40 low energy houses in Australia: 20 houses located in a cool temperate climate (Melbourne) and 20 houses located in a hot humid climate (Darwin). The households completed over 6000 thermal comfort vote surveys which were paired with corresponding environmental data collected within the dwellings. Based on this collected data a model describing the thermal preference of these two cohorts was developed. This paper offers an alternative process by which to judge the potential thermal performance of such low energy houses, using the developed comfort criteria as a performance indicator. This alternative approach is aimed at reducing energy use by demonstrating that an acceptable level of comfort can be achieved without the use of heating and/or cooling appliances. The proposed assessment methodology is aimed at providing a more appropriate pathway to NCC Energy Efficiency compliance certification for these types of low energy houses.

Rising tides: adaptation policy alternatives for coastal residential buildings in Australia

In this work, a risk-based assessment method and benefit-cost analysis to support policy decisions for adapting Australian coastal residential buildings to future coastal inundation hazard is presented. Future coastal inundation is mainly influenced by storm surge and rising sea level. The sea level rises projected by the A1FI, A1B and B1 emissions scenarios developed by the Intergovernmental Panel on Climate Change are considered. The effects of economic and population growth are accounted for by three urban development scenarios: (a) business as usual, (b) urban consolidation and (c) regional development. The adaptation policy actions investigated include a ‘protect’ stance (involving the construction of seawalls), an ‘accommodate’ stance that mandates raising house floors to a certain height (e.g. at heights of 100-year events) and an ‘avoid’ stance that limits new developments in hazardous areas. Policy stances classified as reactive (i.e. action taken after damage being incurred) and anticipatory (i.e. action taken anticipating what will happen) are developed for asset investment choices. In general, adaptation costs are an order of magnitude lower than benefits gained from avoided damages. The results highlight that adaptation action for coastal inundation has a no-regrets character and provides a strong case for reform to ensure that Australia-wide adaptation opportunities are realised.

Air source heat pump water heaters in residential buildings in Australia: Identification of key performance parameters

Heat pump water heaters have been increasingly used to promote energy savings in residential buildings. Nonetheless, their performance may vary significantly due to different site-specific characteristics and technical specifications. To examine this issue, this research study sought to identify key performance parameters for air source heat pump water heaters (ASHPWH) in residential buildings in Australia by using a sensitivity analysis through theoretical models calibrated with empirical measurements. ASHPWH were analysed taking into account their energy performance (i.e. annual energy consumption and energy intensity) and level of service (i.e. compliance with recommended hot water temperatures). The assessment encompassed sensitivity analyses for key performance parameters related to the technical specification of ASHPWH (i.e. coefficients of performance, water heating capacities, hot water storage tank insulation, size and set-point temperature) and site-specific characteristics (i.e. weather conditions, cold water supply temperatures, hot water set-point temperatures and consumption patterns, and the time-distribution of energy according to the electricity tariffs). The findings indicate that the energy performance and the level of service of ASHPWH are mostly influenced by their coefficient of performance and site-specific electricity tariff, respectively. Therefore, careful consideration of ASHPWH technical specifications based on site-specific characteristics should be used to underpin the development of energy efficiency programmes for residential water heaters.

Special Issue on Green and Sustainable Construction Projects: The Facets of Sustainability

Green and sustainable projects have become the norm for new developments. With the increasing environmental consciousness and the aim of combating global warming, many countries are devising policies to promote green and sustainable developments. The primary focus is incentivizing the efficient use of energy. Notably, various concessions are now available for energy saving by using design innovation, choice of materials, and alternative energy sources. Against this background, Azizi et al. reviewed energymanagement strategies reported in literature and developed a framework for assessing the practice of energy management in buildings in Malaysia. The framework includes 19 measures. Using a certified building, a noncertified building, and a conventional building as case studies, it was found that the certified building adopted 18 out of the 19 measures included in the framework. Perhaps that is the main reason the building is certified. More significantly, the case studies also suggest that having a framework provides a convenient start for facilities managers to devise energy-management measures. This, in turn, would make more likely the chance that the facilities managers would employ energy-saving design initiatives. Many governments have taken proactive moves to demonstrate their commitment to reduction of carbon. In Australia, a carbon tax was introduced in 2012. While its effect has not yet been fully realized, Wong et al., with reference to the experience in the European Union project, note that end-users will have to bear the inevitable rise in construction costs. Carbon reduction is now a global trend, and so, the authors remind us, the endeavor for attitude change as a means of understanding is an important part of this process. Nonetheless, a delicate balance has to be maintained between the betterment of humankind and the preservation of the nature. Tam and Zeng developed a set of sustainability-performance indicators to assess residential buildings in Australia. These indicators are artifacts that exemplify the sustainability potential of a building. A survey that the authors took identified that, among the indicators, access to daylight is perceived by the respondents as the most significant connotation of sustainability. In New Zealand, incentivizing schemes are in place to encourage sustainable design. Olorunkiya et al. used the example of lowimpact design (LID) in storm water management to illustrate the paradigm shift. Incentives, in whatever format, can serve as catalysts to boost stakeholders’ interest in implementing LID. This interest can be extended to other sustainable and green construction initiatives. Goh and Rowlinson suggest a maturity model to gauge sustainable construction. The model dwells on five domains: (1) performance, (2) culture, (3) management capability and capacity, (4) tactical framework development, and (5) research and development. This conceptual framework offers an initial baseline to track the evolution of sustainable developments. Further work is suggested to validate the framework. A similar type of maturity model has been developed to illustrate the adoption of information technology. In addition, some examples that highlight the relevancy and usefulness of the proposed framework would be useful. Industrialized construction is one of the means to decrease construction costs and indirectly contributes to sustainable construction. An integrated approach that brings together the expertise of constructors and designers would, in general, further enhance the savings; moreover, it would improve constructability. Jelodar et al. used the Malaysian construction industry as an example to illustrate the importance of having contractors’ input to advance the wider use of industrialized building systems. Also, changes in contracting approaches are advocated to fully embrace industrial building systems as one of the means to achieve sustainable construction.

The relationship between material service life and the life cycle energy of contemporary residential buildings in Australia

Energy use and related greenhouse gas emissions of buildings have a significant effect on the environment. To reduce energy consumption in buildings, it is important to understand energy use occurring across the building life cycle. While previous studies have shown the significance of both the energy required for building operation as well as the energy embodied in initial building construction, an understanding of the total energy embodied in replacement materials over a building's life is not as well developed. One of the key factors affecting this ‘recurring’ embodied energy is the service life of materials. The aim of this study was to investigate the relationship between the service life of materials and the life cycle energy demand associated with contemporary residential buildings in Australia. The initial embodied energy, operational energy and recurrent embodied energy of a detached residential building were calculated with material service life values based on average figures obtained from the literature. These values were then varied to reflect the extent of service life variability likely for a selection of the main building materials and recurring embodied energy recalculated for each scenario. Selected materials of the building were then replaced with commonly used alternatives and the building's initial and recurrent embodied energy recalculated for a range of materials service life scenarios. The results from this initial study indicate that the service life of materials can have a considerable effect on total energy demand associated with a building over its life. This demonstrates the need for further clarity around the service life of materials and the importance of considering the durability of materials when designing and managing buildings for improved energy efficiency. Results from this study also suggest the importance of including the recurrent embodied energy of buildings in building life cycle energy analyses, which in this case represented between 19 and 31% of the life cycle energy of the building as built and 21 and 34% with the use of alternative materials.

Seasonal coolth storage system for residential buildings in Australia

Night sky cooling is explored as an alternative to the conventional cooling technologies using fossil fuels. The night sky cooling method is based on the long wave radiation of unglazed collectors to the sky at night. An evaluation of the night sky cooling system is present for a residential building in three cities of Australia, namely Alice Springs, Darwin and Melbourne. The system comprises an unglazed flat plate solar collector integrated with borehole storage. It uses night sky radiation to reduce the temperature of the ground near to the boreholes. The system was simulated with TRNSYS, a transient simulation program. The simulation results for adequately sized systems show that night sky radiation is able to reduce the coolth storage borehole temperature and the proposed system is able to meet the cooling load of the residential building simulated in three locations. Borehole lengths of 270, 318 and 106 m are required for coolth storage with 90, 260 and 14 m2 collector area for heat rejection in Alice Springs, Darwin and Melbourne, respectively. At the 20th simulation year, the proposed system is able to achieve a system cooling coefficient of performance of 2.2 in Alice Springs, and 2.8 in Darwin and Melbourne.

The Definition Of Scenarios For The Cesare-risk Model

A cost-effective risk assessment model, CESARE-RISK, is being developed for residential buildings in Australia by the Centre for Environmental Safety and Risk Engineering (CESARE) at Victoria University of Technology (VUT). The model is being further developed with funds provided by the Fire Code Reform Centre Ltd (FCRC), Australia. CESARE has been appointed to lead the development of this model, with support from other Australian research organizations. This work uses the methodology developed by Beck and adopts the expected risk-to-life (ERL) and fire-cost expectation (FCE) parameters to appraise the risk and cost associated with the effects of fires in buildings. CESARERISK is a new model, which builds on previous work undertaken in Australia and elsewhere, has a number of new sub models which include fire spread model, detection and activation model, human behavior model and expected number of deaths models. This paper describes some of the fire scenarios which are a central feature of the CESARE-RISK model.

Thermal performance and energy requirements of buildings

The need for simple yet accurate techniques for assessing the thermal performances of buildings is discussed, particularly in relation to residential buildings in Australia. A method is presented for calculating heating or cooling load requirements in terms of indoor temperatures in totally unconditioned (i.e. free-running) buildings. The method accounts for thermal capacitance in the building fabric and intermittent heating or cooling. It can also allow for climatic variability from day to day. The method is a generalization of the variable base degree-day technique which has recently achieved prominence in the United States of America.