- Title
- Low-carbon and affordable retrofits of Australian housing for climate change and scarce resource scenarios
- Creator
- Shiel, John James
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2018
- Description
- Research Doctorate - Doctor of Philosophy (PhD)
- Description
- Climate change is already being felt in Australia, with record-breaking weather extremes and natural disasters. Australian houses need performance retrofits as they have very poor performance and most use air-conditioning at a time when energy prices are escalating. The research undertaken for this thesis used a multidisciplinary approach to cost-benefit research on energy-efficiency retrofits, with greenhouse gas considerations, as well as an alternative thermal comfort approach for the Nationwide House Energy Ratings Scheme (NatHERS). The research encompassed the disciplines of architecture, engineering, housing, construction, quantity surveying, finance, climate change, and human comfort in buildings. The scope of this thesis by publication is: (i) novel retrofits on the candidate’s home, (ii) thermal simulations of the effects of retrofitting three actual house case studies representative of the Australian housing stock, including energy saved, temperatures and humidity, (iii) estimations of heating and cooling carbon emissions using an air-conditioner, (iv) a simple payback period (SPP) cost-benefit analysis with do-it-yourself (DIY) costings, and (v) climate change modelling of ‘Scarce Resource’ and ‘Extreme Climate Change’ scenarios for 2050. Single retrofits that saved the most carbon emissions with the shortest SPPs across all house types were: partitions to reduce the conditioned volume, ceiling insulation, a recommended minimum level of infiltration (i.e. recommended maximum level of sealing or weather-stripping) and external wall cavity insulation. Cost-effective retrofits were then found for various house types e.g. for timber-floored older houses (1950s weatherboard and the 1980s cavity brick) they also included roof and underfloor insulation, and external wall galvanised iron cladding. With sets of retrofit combinations, energy and carbon savings were found by combining the most cost-effective single retrofits into three groups of small, medium and large payback periods for each house, to suit occupant categories. From the graphs provided, occupants can select their SPP, the level of energy or carbon savings, or their budget for retrofits, and the retrofits making up that combination can be determined for each type of house. This approach will help to overcome barriers to retrofitting such as high costs and high payback periods which discourage tenants and landlords, including those with split incentives issues. It also assists householders to make ‘deep retrofits’ that have the largest SPP combinations by identifying the most effective single retrofits to suit their house type. Also, if the Scarce Resource scenario eventuates and prices begin rising for construction resources, the implementation of the retrofits identified in this case will be urgent. An alternative Standard Effective Temperature (SET*) comfort approach adopted in the US (ASHRAE-55, 2010), was researched for the Nationwide House Energy Ratings Scheme (NatHERS) which applies star ratings to new home designs. The research found that the SET* approach could provide savings of up to 95% of the energy for comfort if comfort temperature bands were extended and occupants adopted SET* behaviour. A database was also created to assist in retrofitting houses for ‘cool retreats’, which are zones which heat more slowly under heat wave conditions and which will be necessary for occupants to take refuge under a warming climate. This database can also assist in calibrating NatHERS tools and in establishing SET* parameters. It is recommended to: ask the Australian government to: conduct energy audits and life-cycle carbon analyses to identify existing houses which will benefit from cost-effective retrofit combinations to: lower heating and cooling carbon emissions, lower energy costs, and adapt to climate change by promoting cool retreat retrofits; set minimum infiltration levels for dwellings with and without Energy Recovery Ventilation (ERV) systems; and update the National Greenhouse Accounts Factors handbook for methane’s Global Warming Potential factor; and, promote cost-effective DIY retrofits to Australia’s active renovation movement; provide government subsidies and rebate schemes for house retrofits for those who can’t afford the increasing cost of heating and cooling, and the elderly; ask the NatHERS administrator to: improve NatHERS assumptions to be more realistic, and implement the SET* comfort approach in NatHERS. The limitations of this research included only evaluating one site (Adelaide) for climate modelling, using a house case study method and across only three eras to represent the existing housing stock, and due to assumptions within NatHERS, such as the number of rooms conditioned and the house occupancy level. However, the case study method that was developed demonstrated how retrofits could be compared for savings in carbon emissions and cost savings, and this could be further extended to other types of residential buildings, and locations. This research can be applied to actual houses by using the framework and tools developed to take into account the actual physical characteristics (e.g. construction type, size, era, orientation), the percentage of the house that is actually conditioned, the actual heating and cooling appliance efficiencies, the actual household occupancy, and the real local energy costs and fuel carbon intensities.
- Subject
- cost-effective retrofits; existing Australian housing; climate change; SET* comfort
- Identifier
- http://hdl.handle.net/1959.13/1389034
- Identifier
- uon:32842
- Rights
- Copyright 2018 John James Shiel
- Language
- eng
- Full Text
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| View Details Download | ATTACHMENT01 | Thesis | 10 MB | Adobe Acrobat PDF | View Details Download | ||
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