In this study, the design of output low-pass capacitive–inductive (CL) filters is analyzed and optimized for current-source single-phase grid-connected photovoltaic (PV) inverters. Four different CL filter configurations with varying damping resistor placements are examined, evaluating performance concerning the output current’s total harmonic distortion (THD), the power factor (PF), and power losses. High-frequency harmonics are effectively attenuated by a second-order CL filter with the damping resistor placed parallel to the filter inductor. In addition, this filter type achieves the best performance by minimizing power loss. A systematic design methodology using filter normalization techniques allows to determine the optimum filter parameters based on the specified cut-off frequency (500 Hz), power loss (5% of rated power), and target THD (<5%). The analysis, simulations, and experiments show that under various operating conditions, this approach meets the grid connection standards (current THD < 5%, power factor between 0.8 leading and 0.95 lagging) while improving efficiency.

This paper reports on the effectiveness of gas-boosted solar water heaters in dwellings within an eco-friendly and comprehensively monitored Australian housing development. Unlike some electrical appliances, including the oven, dishwasher, kettle etc., that show unique energy signature patterns, the solar water heaters examined in this paper do not show obvious energy usage patterns. The auxiliary energy consumed by these water heaters depends on the type of booster, i.e. either an instantaneous or the more traditional storage type, as well as the great variety in individual household demand. Given the recent decline in popularity of solar water heating in Australia, and the inability of householders to determine if their gas-boosted solar water heater is operating correctly, this paper determines the effectiveness of 4 gas-boosted solar water heaters (SWHs) within the Lochiel Park Green Village estate. This is achieved by calculating the auxiliary energy used and hence the solar fraction of 2 instantaneous, and 2 storage, type solar water heaters, based on analyses of monitored hot water and gas usage data, collected every minute over an 8-year period. Furthermore, the paper compares a small sample of early monitored data, with modelling used to determine energy savings and compliance in Australia, to highlight the spread of performance outcomes. Finally, the paper describes various installation and design issues found when some householders have suspected their solar-water heater was not operating effectively.

This study evaluates the optimal sizing and economic analysis of the rooftop solar photovoltaic (PV) and lithium-ion battery energy storage system (BESS) for grid-connected households. Two types of households are investigated, i.e., all-electric homes and those supplied with both gas and electricity. Each type of household is investigated under three system configurations: (i) without PV and BESS, (ii) with PV only, and (iii) with PV and BESS (PV-BESS) system. The objective is to minimize the net present value (NPV) of operating each type of house and examine the impact of the generation and storage technologies on these. For the all-electric household, gas demand is converted to electricity demand based on the gas and electric cooking and water heating appliance efficiencies used in this study. The houses NPVs are calculated using real monitored gas and electricity usage data, along with measured, solar irradiation and ambient air temperatures. It is found that the NPV varies for the all-electric and the gas and electric house, and is more prominent for the customers with gas and electric when no PV and BESS are installed. However, the key finding of this study highlights that the PV-BESS system is more economic for the all-electric houses.

A significant shift towards consolidating residential neighbourhoods has dramatically influenced the Australian national urban tree canopy benchmark. Recurrent tree planting, in densely settled residential suburbs, is an insufficient, emerging environmental and long-term energy conservation strategy. A global and Australian original research review, spanning the past two decades, reveals a better understanding of the link between trees and the built environment. This review defines potential tree allocation parameters, in urban energy conservation, within residential landscape constraints. This assessment focuses on regions similar to various Australian temperate to sub–tropical climate zones, defined as Mediterranean climate type by Köppen climate classification. Based on this review, the paper then identifies the importance of residential tree requirements and energy demand credibility projections as an amendment to existing metropolitan guidelines, using Sydney, Adelaide, and Perth in Australia as an example. Currently, Australian residential planning and design codes, and landscaping software action-codes, like iTree canopy software or Tree Planting Predictor Tool, do not consider residential tree arrangement. These parameters unify the building-energy assessment scheme with an optimal residential tree arrangement concept, leading to implementable residential development plans. This optimisation, primarily optimal residential tree arrangement, provides housing designers with ideal tree allocation data to yield the greatest effect. In addition, this optimal residential tree arrangement model will transform how researchers measure future urban canopy cover performance.

Energy-efficient dwellings promote substantial urban energy conservation. Residential tree allocation, as an Urban Heat Island (UHI) mitigation strategy, stimulates climate responsivity, lowers Air Conditioner (AC) usage and heat distribution. This paper evaluates dwellings' response to residential tree planting parameters to assess the building-surround relationship. These parameters include tree type (evergreen or deciduous), volume (1-3 trees), Tree-Building distance (3 m or 5 m) in each cardinal and inter-cardinal azimuth. These planting configurations highlight dominant Australian urban planning policy and green open space restrictions. This study quantifies tree planting configuration models, utilising both typical and extreme weather data and a bi-seasonal approach, to arrive at an Optimal Residential Tree arrangement (ORTa). The simulation process tailors local weather data to assess tree impact upon the diurnal and nocturnal microclimate. The ORTa dependence upon orientation ensures correct deep soil levels and viable private backyard volume. The result demonstrates a high probability that deciduous trees save energy bi-seasonally. Across all aspects and weather conditions, ORTa allows for an evergreen tree addition to boost energy conservation without detrimental annual or bi-seasonal effects on building thermal response. Annual weather data indicates two deciduous trees are optimal. These trees would be located east or west at 3 m Tree-Building distance (T-B distance), north at 5 m T-B distance or south at 3 m minimum with the maximum depending upon neighbour's northerly aspect. In typical weather conditions, two deciduous tree arrangements lead to maximum 40% heating energy conservation from any potential ORTa in east, west or north. In addition, it provides 15% east or west cooling energy saving and 7% north. In extreme weather conditions, two tree arrangements provide 25% thermal heating conservation, in any aspect. During heatwaves easterly deciduous tree planting is optimal (18% energy conservation), followed by westerly (7%) and northerly (1%). This research recommends five ranked optimal tree arrangements depending on residential parcel deep soil availabilities. This optimisation result encourages decision-makers to appreciate residential green space and reanalyse future urban canopy cover target measurements. (c) 2022 Elsevier B.V. All rights reserved.

This paper reviews the national house rating tools in the UK and Australia, evaluates the energy performance of eight different case study houses, and quantifies the magnitude of the performance gap between as-designed energy performance and as-occupied (actual) energy use. To identify contributing factors to the performance gap, post-occupancy evaluations were conducted, and all case study houses were monitored over two years. It was observed that there are performance gaps in all case study houses, however, the gap can be negative (i.e. more actual energy use than simulated) or positive (i.e. less actual energy use than simulated). Results show that the actual heating loads were less than simulated in 5 of the 8 houses (2 UK and 3 AU), and only 1 house (AU) had an actual cooling load more than simulated. The heating discrepancies ranged from 73% to 180% for the UK houses, and 19%-172% for the AU houses. For the cooling loads, actual energy use in the AU house was up to 4.8 times higher than the simulated. To understand the underlying causes, several influencing factors (including internal temperature conditions, climate, house form and urban context, construction quality, and processes and assumptions of national house rating tools) were analysed. It was found that a key challenge relates to a limited definition of the energy system (household energy use), focusing on technical issues and largely ignoring or simplifying existing and changing socio-cultural issues. Additionally, the paper argues for the need for extending the system boundary beyond individual buildings to neighbourhood, community and city scales. At both a building scale and community scale, deeper understandings of socio-cultural issues that impact on, and are impacted by, energy metabolism, are required.

This paper presents a monitoring-based investigation of rainwater collection systems using economic performance indicators in a group of households with nonconventional end-uses for rainwater that are not traditionally associated with rainwater supply. The monitored data for five household rainwater tank systems were analysed in two stages. For the first stage, the data was empirically analysed to develop a method to predict effective roof catchment areas. For the second stage, the effective roof catchment areas, together with roof area connection percentages, were analysed against different types of water demands in individual households. The individual systems were investigated for yield capacities, costs and water security using a modified Roof Runoff Harvesting Systems average annual yield model based on daily water balance procedures. The Life Cycle Costing analysis of the systems using the model was based on the Capital Recovery Method by taking into consideration the capital costs as well as ongoing costs for maintenance, replacement and operation of the systems. The analysis established the optimal sizing requirements for the studied rainwater tanks and their corresponding roof area connectivity.

Single-phase grid-connected photovoltaic (PV) inverters (GCI) are commonly used to feed power back to the utility. However, the inverter output power fluctuates at 100 Hz, which can be seen by the PV panel, and this reduces the PV output power. It is important to determine and analyze the correlation between the array voltage and current ripple and the average output power reduction of PV array. Therefore, this paper investigates the relationships between the oscillations due to single-phase switching and the DC link energy storage for PV GCIs. The balanced ripple definition is introduced and compared with the more common centered ripple definition. Some examples are provided that demonstrate the importance of these results, in the inverter design industry. The analysis presented here incorporates inductor trade-offs, which are verified with experimental results.

Purpose-built low-energy homes have been the subject of policy and researcher scrutiny for many years, and there is plenty of evidence that they deliver substantial energy and carbon emission savings. But are these the best metrics to assess their benefits? What do the occupants think are the most important aspects of living in low-energy and near net zero energy homes? This paper investigates the stories told by households living in purpose-built low-energy homes in the UK, and examines the user experiences that are most important to them. What we find is that the user experience is highly personal, is strongly linked to health and wellbeing experiences, and is focussed around family outcomes rather than rather abstract energy or environmental outcomes. This research has led to the conclusion that we may be asking the wrong questions about purpose-built low-energy homes, and using the wrong metrics to assess the benefits.

International policy settings are looking toward low-energy and near zero-energy homes as a solution to address environmental impacts, particularly anthropogenic climate change. There is increasing research evaluating sustainable housing developments from a technical and occupant perspective. One of the key determinants of household energy use is tenure. However, there is limited research which has looked at if tenure impacts on how occupants experience low-energy homes. This paper contributes to the literature by exploring three low-energy housing developments and exploring the role of tenure in relation to how the households experience the dwellings. The case studies demonstrate that social housing tenants have frustrations with a lack of control over what they could, or could not, do to their low-energy dwellings, in comparison to owner-occupier housing.

Current and newly built buildings will inevitably experience the effects of climate change, therefore, the design and performance of these buildings should consider weather data that includes some of the effects of climate change, instead of only using historical weather data. However, climate change weather data suitable for buildings performance simulation are typically unavailable. This research presents a method to integrate climate change features into historical weather data to make suitable climate change weather data available for buildings performance simulation. The method separates hourly dry bulb temperature into three time series components to simplify the integration of three climate change features. The method adjusts the maximum and minimum monthly averages, the number of days with maximum temperature above a specified threshold, and the number of consecutive occurrences of days with maximum temperature above a specified threshold (heatwave). The research also presents the adjustment of monthly averages of global solar irradiation. Under the climate–changed weather conditions, the annual heating thermal energy decreases by 21%–22%, the annual cooling thermal energy increases by 29%–31%, and the combined heating and cooling thermal energy decreases by 4%–5% compared to the heating and cooling thermal energy under the current weather conditions. The results indicate that climate–changed weather data is necessary as historical weather data is insufficient for accurately assessing the energy performance of a building.

Solar PV systems have become common-place in many cities and regions, and is a core technology in purpose-built low-energy homes, but evidence is emerging that in many cases electricity output may be significantly lower than expected. Information from in-home energy monitoring systems, interviews and informal discussions with residents has shed some light on the experiences and issues faced by the end-user, particularly those associated with operating a solar PV system to achieve a low-carbon lifestyle. Case studies of residents in different ownership and income situations, and from three distinct housing developments in Australia and England are used to highlight end-user experiences. The study finds that the residents face a range of issues including the initial sizing and commissioning, a lack of solar knowledge and expected generation performance, as well as regulatory barriers that limit the opportunity to upgrade system size.

Current regulatory pathways to compliance in energy efficiency for Australian housing are via provisions in the National Construction Code (NCC). This paper first identifies performance evaluation criteria set out in the code presented as a comparative analysis across the different methods of achieving compliance. Jurisdictional and concessional variations are discussed and thereafter an examination of the effect of specific design and location factors that impact the commonly used deemed to satisfy route to compliance. A study is presented in the paper investigating typical South Australian temperate climate housing styles in terms of their expected energy performance and compliance. This is done to test for measurable differences or test where equivalence can be shown to be reasonably achieved. This study highlights the issue of alternative pathways, being different options of using software modelling or elemental compliance based on specification details. The sample set is a modest seven houses only but carefully chosen to show the compliance pathway results for different options across this sample set. Further measures of house energy performance evaluation and comparison are drawn from the literature.

This paper investigates the simple payback period, of retrofitting a typical older existing South Australian house, that improves the star rating from 1.6 to beyond the current new build requirement of 6. The payback period varies between 6.5 and 16 years, using modest fuel escalation rates, and examines the sensitivity of energy tariffs, as well as the energy conversion efficiencies of typical space conditioning systems used in South Australia, i.e. reverse-cycle ducted air conditioning systems, and ducted gas and evaporative coolers.

This study compares the cost of operating the auxiliary components of an optimised standalone hot water fired absorption chiller, using mains grid electricity and an optimised standalone photovoltaic system. The cheaper source was further compared with using mains electricity to operate a conventional reverse cycle air-air heat pump. Both types of air conditioners were sized to condition the same typical Australian house in three different Australian climate zones. The life-cycle cost of the electrical subsystem was determined for a house located in both a city and for a remote (grid-free) locations; the latter assumed the new connection could sustain the energy and power demands of the air conditioner. The operation and life-cycle costs are determined using TRNSYS 17. The results show that mains electricity attracts a lower cost than an optimised PV system for the chiller case; however, the standalone PV system offers a lower cost than mains, when operating a reverse cycle heat pump air conditioner. Finally, the paper shows that investing in a chiller system is better suited to houses in remote locations and in colder climate zones.