• Energy Research
• 2016-2025close
• AU close

Rising demand and limited production of electricity are instrumental in spreading the awareness of cautious energy use, leading to the global demand for energy-efficient buildings. This compels the construction industry to smartly design and effectively construct these buildings to ensure energy performance as per design expectations. However, the research tells a different tale: energy-efficient buildings have performance issues. Among several reasons behind the energy performance gap, occupant behavior is critical. The occupant behavior is dynamic and changes over time under formal and informal influences, but the traditional energy simulation programs assume it as static throughout the occupancy. Effective behavioral interventions can lead to optimized energy use. To find out the energy-saving potential based on simulated modified behavior, this study gathers primary building and occupant data from three energy-efficient office buildings in major cities of Pakistan and categorizes the occupants into high, medium, and low energy consumers. Additionally, agent-based modeling simulates the change in occupant behavior under the direct and indirect interventions over a three-year period. Finally, energy savings are quantified to highlight a 25.4% potential over the simulation period. This is a unique attempt at quantifying the potential impact on energy usage due to behavior modification which will help facility managers to plan and execute necessary interventions and software experts to develop effective tools to model the dynamic usage behavior. This will also help policymakers in devising subtle but effective behavior training strategies to reduce energy usage. Such behavioral retrofitting comes at a much lower cost than the physical or technological retrofit options to achieve the same purpose and this study establishes the foundation for it.

Dans cette étude, nous avons calibré le modèle BioWin pour évaluer la consommation d'énergie, les émissions de gaz à effet de serre et le taux de nitrification volumétrique dans le traitement de l'urine à haute teneur en ammoniac et séparée par la source dans une station d'épuration décentralisée. Dans un premier temps, nous avons validé le modèle en utilisant des processus de traitement par bioréacteur à membrane urinaire (MBR) à l'échelle du laboratoire. Par la suite, le modèle BioWin à grande échelle a été utilisé pour évaluer la performance d'un système de traitement de l'urine à grande échelle. Les résultats de simulation pour le traitement de l'urine par procédé MBR, optimisés à un point de consigne d'oxygène dissous de 3 mg/L, ont révélé une consommation d'énergie de 3 kWh/kg N, des émissions de gaz à effet de serre de 25,6 kg CO2e/m3 et un taux de nitrification volumétrique de 310 mg N/L/j. Remarquablement, cela ne représente que 25–30 % de l'énergie totale dépensée dans la synthèse à l'échelle industrielle d'un engrais vierge utilisant le procédé Haber-Bosch. Nos résultats indiquent que la demande énergétique collective d'une STEP urinaire détournée et d'un MBR urinaire séparé pour la récupération des engrais est comparable à celle d'une STEP MBR conventionnelle sans récupération des nutriments. Il est important de noter que le détournement de l'urine réduit les émissions de gaz à effet de serre et l'empreinte globale de la station d'épuration par rapport aux stations conventionnelles. De plus, la récupération des nutriments par la séparation et le traitement des sources d'urine contribue de manière significative à la récupération des nutriments et aux économies circulaires. En este estudio, calibramos el modelo BioWin para evaluar el consumo de energía, las emisiones de gases de efecto invernadero y la tasa de nitrificación volumétrica en el tratamiento de orina con alto contenido de amoníaco y separada por fuentes dentro de una planta de tratamiento de aguas residuales descentralizada (EDAR). Inicialmente, validamos el modelo utilizando procesos de tratamiento de biorreactor de membrana urinaria (MBR) a escala de laboratorio. Posteriormente, se empleó el modelo BioWin ampliado para evaluar el rendimiento de un sistema de tratamiento de orina a gran escala. Los resultados de la simulación para el tratamiento de orina mediante el proceso MBR, optimizado a un punto de ajuste de oxígeno disuelto de 3 mg/L, revelaron un consumo de energía de 3 kWh/kg N, emisiones de gases de efecto invernadero de 25,6 kg CO2e/m3 y una tasa de nitrificación volumétrica de 310 mg N/L/d. Sorprendentemente, esto constituye solo el 25–30 % de la energía total gastada en la síntesis a escala industrial de un fertilizante virgen utilizando el proceso Haber-Bosch. Nuestros hallazgos indican que la demanda de energía colectiva de una EDAR desviada de orina y un MBR de orina separado para la recuperación de fertilizantes es comparable a la de una EDAR MBR convencional sin recuperación de nutrientes. Es importante destacar que el desvío de orina reduce las emisiones de gases de efecto invernadero y la huella global de la EDAR en comparación con las convencionales. Además, la recuperación de nutrientes a través de la separación y el tratamiento de la fuente de orina contribuye significativamente a la recuperación de nutrientes y a las economías circulares. In this study, we calibrated the BioWin model to assess the energy consumption, greenhouse gas emissions, and volumetric nitrification rate in the treatment of high-ammonia-containing, source-separated urine within a decentralised wastewater treatment plant (WWTP) setting. Initially, we validated the model using lab-scale urine membrane bioreactor (MBR) treatment processes. Subsequently, the upscaled BioWin model was employed to evaluate the performance of a full-scale urine treatment system. Simulation results for urine treatment by MBR process, optimized at a dissolved oxygen set point of 3 mg/L, revealed an energy consumption of 3 kWh/kg N, greenhouse gas emissions of 25.6 kg CO2e/m3, and a volumetric nitrification rate of 310 mg N/L/d. Remarkably, this constitutes only 25–30 % of the total energy expended in the industrial-scale synthesis of a virgin fertiliser using the Haber-Bosch process. Our findings indicate that the collective energy demand of a urine diverted WWTP and a separate urine MBR for fertiliser recovery is comparable to that of a conventional MBR WWTP without nutrient recovery. Importantly, urine diversion reduces greenhouse gas emissions and the overall footprint of the WWTP compared to conventional ones. Moreover, nutrient recovery through urine source separation and treatment contributes significantly to nutrient recovery and circular economies. في هذه الدراسة، قمنا بمعايرة نموذج BioWin لتقييم استهلاك الطاقة وانبعاثات غازات الدفيئة ومعدل النترجة الحجمي في معالجة البول عالي الأمونيا المفصول عن المصدر داخل بيئة محطة معالجة مياه الصرف الصحي اللامركزية (WWTP). في البداية، تحققنا من صحة النموذج باستخدام عمليات معالجة المفاعل الحيوي لغشاء البول على نطاق المختبر (MBR). بعد ذلك، تم استخدام نموذج BioWin الموسع لتقييم أداء نظام معالجة البول على نطاق واسع. كشفت نتائج المحاكاة لمعالجة البول عن طريق عملية MBR، المحسنة عند نقطة ضبط الأكسجين المذاب البالغة 3 مجم/لتر، عن استهلاك طاقة قدره 3 كيلو واط في الساعة/كجم نيوتن، وانبعاثات غازات الدفيئة البالغة 25.6 كجم من مكافئ ثاني أكسيد الكربون/م 3، ومعدل نترتة حجمي قدره 310 مجم نيوتن/لتر/يوم. ومن اللافت للنظر أن هذا لا يشكل سوى 25–30 ٪ من إجمالي الطاقة المستهلكة في التوليف الصناعي للأسمدة البكر باستخدام عملية هابر بوش. تشير النتائج التي توصلنا إليها إلى أن الطلب الجماعي على الطاقة من محطة معالجة مياه الصرف الصحي المحولة للبول و MBR منفصل للبول لاستعادة الأسمدة يمكن مقارنته بالطلب على الطاقة من محطة معالجة مياه الصرف الصحي التقليدية بدون استعادة المغذيات. والأهم من ذلك، أن تحويل البول يقلل من انبعاثات غازات الدفيئة والبصمة الإجمالية لمحطة معالجة مياه الصرف الصحي مقارنة بالمحطات التقليدية. علاوة على ذلك، يساهم استرداد المغذيات من خلال فصل مصدر البول ومعالجته بشكل كبير في استرداد المغذيات والاقتصادات الدائرية.

Real driving emissions (RDE) testing are gaining attention for monitoring and regulatory purposes because of providing more realistic emission and fuel consumption measurements compared to laboratory tests. This study aims to develop machine learning (ML) based emission and fuel consumption estimation models using real-driving measurement data. A light-duty diesel vehicle equipped with a portable emissions measurement system (PEMS) was driven in an urban test route by 30 participant drivers of disparate backgrounds to obtain a wide variety of data in terms of driving behaviour and traffic conditions. The Pearson correlation coefficient was used to select the input variables among 36 driving behaviours and 6 engine parameters. The CO2, NOx and fuel consumption prediction models were developed using linear regression (LR), support vector machine (SVM) and Gaussian process regression (GPR). The results showed that all three models could predict CO2 with an absolute relative error (ARE) of less than 9%. The GPR model showed the best performance in CO2 prediction with an R2 of 0.74 and ARE of 3.30%. LR model showed the best prediction accuracy for NOx with an R2 of 0.80 and ARE of 8.91%. All three models worked well for fuel consumption prediction, however, GPR showed the best accuracy with an R2 of 0.81 and ARE of 3.52%. This method lays a foundation for developing route/region specific emission and fuel consumption models that will help to monitor and reduce the environmental impact and the amount of burned fuel. Moreover, developing models from different driver classes will provide valuable insights into emission-optimal driving behaviour which could be used to train new drivers.

Waste management is an area of significant global concern. The reuse of waste materials (such as: plastics, glass, wood, etc.) in concrete manufacturing has been studied for potential cost savings, improvements in quality, and reduction of environmental impact leading to sustainability. This study examines the performance of concrete containing recycled polyethylene terephthalate (PET) waste in granular form to replace the fine aggregate. A series of concrete specimens for Grade 32 concrete mix were cast using PET granules as partial replacement to fine aggregates in the mixture (0%, 10%, 30%, and 50% replacement by volume of fine aggregate). Important properties such as workability (slump), density, compressive strength, elastic modulus, tensile strength, flexural strength, and crack mouth opening displacement (CMOD) were evaluated together with the microstructural observations. The experimental results indicated that volumetric replacement of fine aggregates with 10% recycled PET granules positively impacted the characteristics of the concrete. The findings further revealed an improvement in the ductility of concrete with recycled PET granules content, albeit the effect was more pronounced with the concrete containing 10% PET granules. The experimental results for the mechanical properties were compared against available Australian and American design guidelines and a strong linear relationship is observed. Lastly, the findings of this study on mechanical properties revealed an optimum performance relative to those reported in the available literature, particularly for the concrete with 10% of fine aggregate replaced by PET granules.

Liquefied natural gas (LNG) projects are regulated by host countries, but policy and regulation should depend on geography and meteorology. Without considering the role of geography and meteorology, sub-optimal design choices can result, leading to energy conversion efficiency and capital investment decisions that are less than ideal. A key step in LNG is regasification, which transforms LNG back from liquid to the gaseous state and requires substantial heat input. This study investigated different LNG regasification technologies used around the world and benchmarked location and meteorology-related factors, such as seawater temperatures, ambient air temperatures, wind speeds and relative humidity. Seawater vaporizers are used for more than 95% of locations subject to water quality. Ambient air conditions are relatively better for South America, India, Spain and other Asian countries (Singapore, Taiwan, Indonesia, and Thailand) and provide a much cleaner regasification technology option for natural and forced draft systems and air-based intermediate fluid vaporizers. On a global basis, cold energy utilization currently represents <1% of the total potential, but this approach could deliver nearly 12 Gigawatt (GW) per annum. Overall, climate change is expected to have a positive financial impact on the LNG regasification industry, but the improvement could be unevenly distributed.

Sand, gravel, and crushed stone are the most mined materials on Earth. Aggregates constitute the foundation for modern civilization and are essential for providing shelter, infrastructure, and communication, but are an increasingly scarce resource. Here, we review the interconnections between the impacts of aggregate mining and the services they provide. We show that the conflicting impacts on the environment and humankind disrupt the net positive effects of aggregate mining on sustainable development. Focusing on low- and middle-income countries, we link these interconnections to the United Nations Sustainable Development Goals and identify critical obstacles to a sustainable future for global aggregate resources. Our assessment identifies an urgent need to improve knowledge on: (1) direct and indirect impacts of extraction on human health, (2) system-level impacts on ecosystems and the services they provide, and (3) how to meet the projected trajectories of global aggregate demand.

Researchers have been driven to investigate sustainable alternatives to cement production, such as geopolymers, due to the impact of global warming and climate change resulting from greenhouse gas emissions. Currently, they are exploring different methods and waste materials to enhance the mechanical and physical properties of geopolymer and expand its application range. This review paper offers a thorough analysis of the utilization of various waste materials in geopolymer manufacturing and shows the creative contribution of this research to the development of environmentally friendly cement substitutes. The article covers the properties, durability, and practical applications of geopolymer composites made from various waste binders. It includes a microstructure and chemical analysis. The research findings indicate that geopolymers are an effective cementitious binder substitute for cement in various applications. Additionally, the ecological and carbon footprint analysis highlights the sustainability of geopolymers compared to cement.