| Popis: |
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. |
