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This paper focused on the environmental performance of a nearly zero-energy wood-based educational building (NZEB-W) via the life cycle impact assessment (LCIA). It identifies the environmental impacts of construction materials and operational energy demands of the NZEB-W and compares them using the SimaPro 8 software with the IMPACT 2002+ method. The LCIA results from NZEB-W show that the overall environmental impact of construction materials (98.9 Pt) and 45 years operational energy demands (98.6 Pt) will be at the same level. Its overall environmental impact 197.75 Pt for 45 years is relatively small. NZEB-W has the greatest impact on the environment in the category of damage respiratory inorganics (34.5%), 419 kg PM2.5 eq from construction materials, and 271 kg PM2.5 eq from operational energy for 45 years; follows global warming (31.7%), 1.98 × 105 kg CO2 eq from construction materials, and 4.23 × 105 kg CO2 eq from operational energy for 45 years; and non-renewable energy (21.8%), 2.82 × 106 MJ primary from construction materials, and 3.73 × 106 MJ primary from operational energy for 45 years. As this environmental assessment shows, the material composition of construction materials compared to the energy consumption in the use phase is an essential element for understanding the life cycle impact of buildings.

Abstract With the global energy consumption reaching unsustainable levels, the need for regulating energy consumptions has been emphasised. Hence a variety of methods are followed in different countries to minimise the impacts of embodied energy (EE) and operational energy (OE) in buildings. Considering either EE or OE in its individuality is not a pragmatic approach and it is important to consider means of reducing both EE and OE in parallel. The design stage was identified as the most suitable stage for integrating energy efficiency measures, since most crucial project decisions are taken at this stage. Although a multitude of research has been conducted on EE and OE individually, there seems a lack of research that focuses on both these aspects together. The extensive literature review was followed by 5 preliminary interviews with subject matter experts and then semi structured interviews with 12 experts were conducted. It was revealed that determining strategies for achieving simultaneous EE and OE reduction is difficult. The identified strategies to be implemented in the design stage were classified as material selection related, design approach related, building morphology related, procurement process related and other strategies, with a majority of strategies falling under the ‘procurement process’ category.

Reducing the lifecycle energy use of buildings with renewable energy applications has become critical given the urgent need to decarbonize the building sector. Multi-objective optimizations have been widely applied to reduce the operational energy use of buildings, but limited studies concern the embodied or whole lifecycle energy use. Consequently, there are issues such as sub-optimal design solutions and unclear correlation between embodied and operational energy in the current building energy assessment. To address these gaps, this study integrates a multi-objective optimization method with building energy simulation and lifecycle assessment (LCA) to explore the optimal configuration of different building envelopes from a lifecycle perspective. Major contributions of the study include the integrated optimization which reflects the dynamics of the whole lifecycle energy use. Insights from the study reveal the optimal configuration of PV and composite building façades for different regions in sub-Saharan Africa. The lifecycle energy use for the optimized building design resulted in 24.59, 33.33, and 36.93% energy savings in Ghana, Burkina Faso, and Nigeria, respectively. Additionally, PV power generation can efficiently cover over 90% of the total building energy demand. This study provides valuable insights for building designers in sub-Saharan Africa and similar areas that minimize lifecycle energy demand.

Globally, the building sector consumes approximately 60% of the total energy usage, while the energy consumption of residential buildings lies between 20% to 40%. The majority of this energy is operational energy, which comes mainly from the heating and cooling of houses. Innovative and cost-effective insulation materials have the potential to reduce the operational energy requirements and can therefore make the buildings more energy efficient. In this study, three commonly available insulation materials were experimentally evaluated for a case study of residential buildings, located in a cold region of Pakistan. Glass wool, extruded polystyrene, and polyethylene were used, as insulation materials, for monitoring the case study building performance. Thermal data were collected for 21 days in the year 2019 using a Testo Saveries System and were then used for analyzing the thermal performance of each of the three types of insulation materials. Other relevant data including the cost of insulation materials, thickness, ease of application, design life, and fire resistance of the selected insulation materials were obtained for broader (based on the scorecard) analysis based on a multi-weighted decision model. It was concluded that Polyethylene was the most economical insulation material amongst the others, which also showed the best thermal performance. Polyethylene was also found to be the best insulation material for the case study building based on a multi-weighted decision model and, hence, is recommended for application in buildings around cold regions of Pakistan.

Abstract Although recent studies demonstrate the importance of including the Embodied Energy (EE) in building analysis, only the Operational Energy (OE) is currently taken into account in building energy demand calculation method. In particular, the EE plays an important role in tall buildings evaluation, because the energy demand increases with building height. Aim of this study was to assess the Embodied Energy in evaluation of different types of tall building facade systems performances along with the Operational Energy, pointing out the importance of taking into account both these aspects. Within the research activity here presented, 8 glazed envelope typologies, in 5 different climate zones, have been evaluated.

Na busca por redução dos impactos energéticos associados a todo ciclo de vida da edificação, a avaliação do ciclo de vida energético - ACVE, mostra-se uma ferramenta eficaz. O artigo tem como objetivo identificar e classificar a disponibilidade de dados para o emprego dessa ferramenta com escopo, “berço ao túmulo”, adotando vida útil de 50 anos em uma residência em Belém do Pará. A metodologia, estudo de caso, considerou as etapas mais utilizadas de ACVE de edificações residenciais, com dados secundários e conceito metodológico obtido em pesquisa científica de Tavares (2006) e Caldas, et al (2016). O resultado do consumo energético total para o cenário existente, foi 62.75 GJ/m². A energia operacional na etapa de uso, apresentou o maior consumo energético, 69% em 50 anos, seguida da energia incorporada inicial com 28%. Na classificação dos dados obtidos concluiu-se que, 20% dos dados demandam estudos abrangentes. Refletindo a necessidade desses estudos para os valores de energia incorporada nos materiais e sistemas construtivos, voltados para realidade brasileira e regional. Assim, a análise dos dados obtidos deve ser realizada com cautela e de forma híbrida, critério utilizado dependendo da disponibilidade e dificuldade na obtenção dos dados necessários para o cálculo da energia incorporada.

Thermally active building systems (TABS), which are integrated with the structure of a building, provide a robust approach for utilising renewable energy. However, reinforced concrete, where TABS are typically placed, is responsible for a significant proportion of initial embodied energy and related greenhouse gas emissions. Therefore, combining lightweight structural elements and thermal systems reduces initial embodied energy usage while retaining the active material's thermal storage and heat transport benefits. The present experimental work explores the operational performance of a prototype of a lightweight TABS at ceiling level. A small-scale climate chamber was constructed and equipped to evaluate the prototype in the key operating modes. The study investigated the relationship between the supply temperature of the lightweight TABS and the climate chamber's internal air temperature for active heating, active cooling and natural ventilation modes. The experiments compared the reaction time in active heating mode for a range of supply temperatures. In addition, we examined the dynamic characteristics of the thermal mass of the lightweight TABS in passive natural ventilation mode and passive cooling mode in the presence of an internal thermal load. The results provide insights into the dynamic performance in operation. In heating mode, we identified the time lag between the radiant surface achieving a steady state and the conditioned air reaching its target temperature. This feature emphasises the significance of refining control strategies when designing comfortable environments with low-temperature heating systems at ceiling level. Further, we highlighted the importance of balancing decisions on minimising embodied energy with the suitability of the selected material to leverage renewable energy sources. The experimental data can be used for validating high-resolution numerical models, which support the development of multifunctional elements with renewable energy sources for building heating and cooling. Journal of Building Engineering, 78 ISSN:2352-7102