Cost Effective, Zero Energy Home Designs for Temperate and Tropical Climates in Australia
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Cost effective, zero energy home designs for temperate and tropical climates in Australia By Sihong GONG A thesis in fulfilment of the requirements for the degree of Doctor of Philosophy School of Photovoltaic and Renewable Energy Engineering Faculty of Engineering University of New South Wales Sydney, Australia January 2020 Thesis/Dissertation Sheet Surname/Family Name : Gong Given Name/s : Sihong Abbreviation for degree as give in the University calendar : PhD Faculty : Engineering School : School of Photovoltaic and Renewable Energy Engineering Cost effective, zero energy home designs for temperate and tropical climates Thesis Title : in Australia Abstract 350 words maximum: (PLEASE TYPE) Due to the renewed interest in Australia in improving the minimum energy performance in the building code and the declining price of a residential PV system, there is an opportunity to examine more closely the cost effectiveness of improvements to building thermal performance and PV systems. Moreover, reducing peak thermal loads is another important issue to be considered due to the increasing usage of air conditioning. In this thesis, experimental measurements of a low energy dwelling in Perth, Western Australia, were compared with modelled results. The results indicated that the dwelling could perform as designed with little auxiliary heating and cooling. Using the validated model as a starting point, the design of the dwelling was optimised to minimise the cost of construction and operating energy consumption using EnergyPlus. Three locations in Australia (Sydney, Melbourne and Darwin) were investigated and a parametric study was conducted. In the absence of a PV system, the most cost-effective design achieved a NatHERS star rating of 7.6-star in Sydney, 7.0-star in Melbourne and 6.3-star in Darwin. When combined with a PV system, designed to offset the electricity costs of HVAC, the PV system was deemed cost-effective based on a benefit-cost ratios analysis. After being combined with a PV system, the 8-star design in Sydney was only marginally more expensive than the most cost-effective option of a 6-star design. In Melbourne and Darwin, the most cost-effective design option was a 7-star and 6-star design, respectively. To reduce peak electricity loads, preconditioning strategies were investigated for a range of house designs integrated with a 5 kW PV system in the three cities. Weather data for the most extreme hot and cold periods over the past 10 years were selected. Two preconditioning scenarios were considered which consisted of preconditioning with continuous HVAC and constant set points and preconditioning with additional thermal conditioning powered by surplus PV generation. The results indicated that peak cooling loads were higher than the peak heating loads for all three cities. To reduce peak cooling loads, the latter preconditioning scenario achieved the best overall performance for reducing peak loads and imported electricity usage. Declaration relating to disposition of project thesis/dissertation I hereby grant to the University of New South Wales or its agents a non-exclusive licence to archive and to make available (including to members of the public) my thesis or dissertation in whole or in part in the University libraries in all forms of media, now or here after known. I acknowledge that I retain all intellectual property rights which subsist in my thesis or dissertation, such as copyright and patent rights, subject to applicable law. I also retain the right to use all or part of my thesis or dissertation in future works (such as articles or books). …………………………………………………………… ……….……………………...…….… Signature Date The University recognises that there may be exceptional circumstances requiring restrictions on copying or conditions on use. 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Publications can be used in their thesis in lieu of a Chapter if: • The candidate contributed greater than 50% of the content in the publication and is the “primary author”, i.e. the candidate was responsible primarily for the planning, execution and preparation of the work for publication • The candidate has approval to include the publication in their thesis in lieu of a Chapter from their supervisor and Postgraduate Coordinator. • The publication is not subject to any obligations or contractual agreements with a third party that would constrain its inclusion in the thesis Please indicate whether this thesis contains published material or not: This thesis contains no publications, either published or submitted for ☐ publication Some of the work described in this thesis has been published and it ☒ has been documented in the relevant Chapters with acknowledgement This thesis has publications (either published or submitted for ☐ publication) incorporated into it in lieu of a chapter and the details are presented below CANDIDATE’S DECLARATION I declare that: • I have complied with the UNSW Thesis Examination Procedure • where I have used a publication in lieu of a Chapter, the listed publication(s) below meet(s) the requirements to be included in the thesis. Candidate’s Name Signature Date (dd/mm/yy) Sihong Gong 20/06/2020 Abstract Due to the renewed interest in Australia in improving the minimum energy performance in the building code and the declining price of a residential PV system, there is an opportunity to examine more closely the cost effectiveness of improvements to building thermal performance and PV systems. Moreover, reducing peak thermal loads is another important issue to be considered due to the increasing usage of air conditioning. In this thesis, experimental measurements of a low energy dwelling in Perth, Western Australia, were compared with modelled results. The results indicated that the dwelling could perform as designed with little auxiliary heating and cooling. Using the validated model as a starting point, the design of the dwelling was optimised to minimise the cost of construction and operating energy consumption using EnergyPlus. Three locations in Australia (Sydney, Melbourne and Darwin) were investigated and a parametric study was conducted. In the absence of a PV system, the most cost-effective design achieved a NatHERS star rating of 7.6-star in Sydney, 7.0-star in Melbourne and 6.3-star in Darwin. When combined with a PV system, designed to offset the electricity costs of HVAC, the PV system was deemed cost-effective based on a benefit-cost ratios analysis. After being combined with a PV system, the 8-star design in Sydney was only marginally more expensive than the most cost-effective option of a 6-star design. In Melbourne and Darwin, the most cost-effective design option was a 7-star and 6-star design, respectively. To reduce peak electricity loads, preconditioning strategies were investigated for a range of house designs integrated with a 5 kW PV system in the three cities. Weather data for the most extreme hot and cold periods over the past 10 years were selected. Two preconditioning scenarios were considered which consisted of preconditioning with continuous HVAC and constant set points and preconditioning with additional