Working from home (WFH) has been imposed due to the COVID-19 pandemic. The adoption of WFH impacts energy use in the residential, commercial, and transportation sectors. Consequently, this affects ...the greenhouse gas emission (GHGE) and the associated energy costs to workers and employers. This study estimates the effects of WFH on the GHGE and energy-related costs in the residential, commercial, and transportation sectors. A simple linear model was used to estimate the changes in the GHGEs and cost by a typical employee when WFH practice is adopted for 1.5 and 4 days per week. The adoption of WFH reduces the operational GHGE accounted for commercial buildings and transport. However, it increases the operational GHGE accounted for residential buildings, which is a maximum of about 6% and 12%, respectively, for WFH 1.5 and 4 days. The reduction of GHGE from transport is significantly higher than that of residential buildings. The GHGE reductions from the transport sector are about 30% and 80%, respectively, for WFH 1.5 days and 4 days per week. WFH for 1.5 and 4 days per week reduces the national annual GHGE by about 1.21 Mt CO2-e and 5.76 Mt CO2-e, respectively. Further, the annual transportation cost of an employee is reduced by 30% and 80% in each city when the employee WFH for 1.5 and 4 days per week. The outcomes of this study offer a direction to reduce energy consumption and related costs and potential future research avenues on this topic. Further, the findings also help policymakers develop a hybrid work model for the post-COVID-19 pandemic.
•Generally, timber buildings have lower sound reduction index in low frequency range.•Most guidelines on vibro-acoustic of the floor are based on older systems (heavier).•Flanking sound transmission ...creates noise issues in lightweight timber buildings.•Software tools for sound transmission in timber buildings are limited.•A comprehensive approach to assess the impact generated noise needs to be developed.
Timber usage in the Australian construction industry has significantly increased due to its strength, aesthetic properties and extended allowances recently introduced in building codes. However, issues with acoustic performance of lightweight timber buildings were reported due to their inherit product variability and varying construction methods. This article reviews the recent literature on the transmissions of impact and airborne sounds, flanking transmission of timber buildings, and the state of computer prediction tools with reference to the Australian practice. An in-depth analysis of issues and an objective discussion related to acoustic performance of timber buildings are presented. Timber is a lightweight material and shows low airborne sound resistance in low frequency range. Attenuation of sound transmission with addition of mass, layer isolation, different products like cross-laminated timber and prefabrication are discussed. Challenges in measuring sound transmissions and reproducibility of results in low frequency ranges are discussed. Well-defined measurement protocols and refined computer simulation methods are required. The serviceability design criteria for modern lightweight timber applications in Australia need to be re-evaluated in the area of impact generated sound. Developing computer tools to predict airborne and impact sound transmission in lightweight timber buildings is quite challenging as several components such as timber members and complex connections with varying stiffnesses are non-homogeneous by nature. Further, there is a lack of experimentally validated and computationally efficient tools to predict the sound transmission in timber buildings. Computer prediction tools need to be developed with a focus on mid-frequency transmission over flanks and low-frequency transmission of timber and prefabricated buildings.
•CLT building showed 30% less LGHGE compared with a RC building in Melbourne.•A reduction of 1.3% of LCC was observed for CLT compared with a RC building in Melbourne.•CLT building has an advantage ...in terms of LCC and LCGHGE in the construction/EOL phases, but not in the operation phase.•Energy efficient methods and reuse/recycling at EOL can enhance LC performance of CLT buildings.
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.
•Microencapsulated PCM in substitution of sand increase heat capacity of concrete.•Fineness of PCM involves a filler effect and increase cement hydration.•Low density of PCM compared with fine ...aggregates reduces compressive strength.•Microencapsulated PCM remain intact in the cementitious matrices during mixing.•Blend of 20% v/v is proposed as optimum PCM replacement in cement-based materials.
More efficient energy usage in buildings with increased thermal mass and better thermal insulation has attracted considerable attention in recent years. As one the most widely used construction materials in the building industry, concrete has a great potential to be converted to a high performance thermal storage material by using phase change materials (PCMs). To demonstrate this, mortar and concrete mixes were blended with microencapsulated PCM as part replacement of fine aggregates and assessed for improved thermal performance. Specimens with varying amount of microencapsulated PCM were tested using calorimetry, differential scanning calorimetry (DSC), thermogravimetry (TGA), scanning electron microscopy (SEM), compressive strength and thermal conductivity. Results show that high specific surface of microencapsulated PCM particles has induced an acceleration of the cement hydration. However, the compressive strength at 28days is still decreased when fine aggregates were substituted by PCM. Contrary to past observations, microencapsulated PCM is observed to remain intact in the cementitious matrices and contributed significantly to improve the heat capacity as well as to reduce the thermal conductivity of the mixes tested. A blend with 20%·v/v replacement was identified as the optimum PCM replacement.
•TRNSYS Type 1270, PCM component was validated with experimental data in literature.•Validated component was used to simulate PCM as a roof layer in a residential house.•PCM roof layer can reduce ...both the annual cooling and heating loads.•PCM roof layer can reduce both peak cooling heating demands.•The optimum phase transition temperature for Melbourne and Sydney is 23°C.
This paper assesses the effectiveness of Phase Change Materials (PCMs) for the improvement of the thermal performance and the thermal comfort of a residential building in Melbourne. The incorporation of PCMs in buildings with their significant heat storage capacity can delay the heat transfer and reduce the cooling and heating loads. Numerical simulation is a useful tool for comprehensive assessments and optimization of PCM applications in buildings. Thus an available TRNSYS component, PCM Wall: Type1270, was implemented with Type56 (Multi zone component). PCM Wall TRNSYS component has been validated with some experimental data published in the open literature. The validated model was then utilised to simulate the thermal performance of a residential building which has a PCM roof layer. The building is a typical single-storey, three bed room residential building in Melbourne. It was found that the PCM roof layer can reduce the cooling and heating loads whilst providing better thermal comfort for occupants with reduced indoor temperature fluctuations.
•FEM model was developed to predict thermal properties of mortar/concrete with PCM.•The model was validated with experiments; it also agrees with analytical model.•Multi-scale model can be applied ...for design optimisation.•Thermal storage wall with optimum amount of PCM improves energy performance.
The incorporation of phase change materials (PCMs) in building envelopes for passive thermal storage can enhance the thermal mass effect and thereby reduce energy consumption. In this investigation, multi-scale analysis of cementitious mortar and concrete containing microencapsulated PCM (MPCM) was performed experimentally and using numerical simulations. A three-dimensional two phase random composite model, which can be integrated with finite element method, was developed to predict the effective thermal properties of cementitious mortar and concrete with MPCM. MPCM was considered as inclusions in a continuous mortar matrix and the latent heat of PCM was incorporated into the simulations. The results showed that the effective thermal conductivity is strongly correlated with the volume fraction of PCM and is independent of the spatial distribution of the inclusions. These predictions were within the upper and lower bounds of parallel and series analytical models and agreed well with the experimental data (correlation coefficient 0.96 for concrete and 0.98 for mortar). Numerical simulations of the macro-scale behaviour of mortar and concrete with PCM for passive thermal storage showed a reduction in the maximum heat flux and time lag effect subjected to diurnal temperature variations. However, an optimum amount of PCM should be selected to fully exploit these passive systems. The developed models can be applied for optimising the design of composites to achieve the best thermal performance.
Affordable housing is characterised by its poor indoor environment, thermal performance, and energy poverty. Conditions are expected to worsen because of urban heat island effect, climate change and ...economic crisis. The poor indoor atmosphere and economic burden can have detrimental effects on occupant health and well-being. This study presents a comprehensive review of evidence-based studies related to thermal comfort, energy consumption and methods used for improvements in low-income households. It was found that energy poverty patterns and methods for efficient use of energy highly depend on the local climate conditions, building stock and specific energy consumption patterns of the occupants. There are few evidence-based studies on thermal performance and indoor thermal comfort of affordable housing in Australia and, therefore, local studies are essential for more targeted policy developments in this area. This could be hampered by challenges in performance monitoring and improvement methods in social housing dwellings caused by the social and economic vulnerabilities faced by the occupants in this segment.
•Poor thermal performance is clearly prevalent in social/affordable housing sector.•Published data on energy performance of affordable housing in Australia is limited.•Strategies for improvements in thermal performance can vary geographically.•Occupant behaviour and local climate is important in selecting countermeasures.•Quantitative local studies are required to understand the scale of the problem.
The application of textile waste as an aggregate in concrete enhances sustainability in construction and promotes circular economy. This work develops a novel fibre-based concrete incorporating ...textile waste fibres. The experiments showed that including textile waste fibres reduces flowability of concrete and improves its tensile and compressive strengths, alongside strain resistance. The fibres enhance concrete’s ductility and resilience against environmental damage. Textile waste fibre exhibits a lower greenhouse gas emissions compared to other non-polymer fibres. This work emphasises the benefits of textile waste in enhancing construction sustainability and highlights the need for expanded exploration.
•Textile waste fibres as an aggregate in concrete was investigated.•Including textile waste fibres reduces flowability of concrete.•It improves tensile and compressive strengths, alongside strain resistance.•Textile waste fibres have a lower life cycle greenhouse gas emission.
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