• Energy Research

This study introduces a Solar Energy-Powered Embedded Pipe Envelope System (SEPES) designed to enhance indoor thermal comfort and reduce heating loads during the heating season. To achieve this objective, a dynamic simulation model coupling a SEPES and building thermal environment was established under the TRNSYS environment. Based on the model, a case analysis was conducted to investigate the operational characteristics of the system during the heating season in a rural building in Beijing. The results indicate that, on the coldest heating day, the system can elevate the indoor temperature by 14.5 °C, reducing the daily heat load from 76.3 kWh to 20.3 kWh, achieving a remarkable energy savings of 73.4%. Additionally, due to the utilization of lower solar heat collection temperatures, the energy efficiency of the system reaches 26.9%. Throughout the entire heating season, the SEPES system enhances the natural indoor temperature by 13.3 °C to 16.6 °C, demonstrating significant effectiveness. Moreover, regional adaptability analysis indicates that the SEPES achieves energy savings ranging from 43.9% to 66% during the heating season in cold regions and regions with hot summers and cold winters in China. Overall, the SEPES is most suitable for climates characterized by both low temperatures and abundant solar radiation in order to achieve optimal performance.

The electronic industry is a fast-growing trade. Its speedy development quickly leads to obsoleting the devices. The e-plastic, as the second major component in e-waste after metal components, is costly yet challenging to recycle due to the complexities of the plastic resin mixtures. Therefore, utilising e-plastic to replace natural coarse aggregate in concrete material can reduce the environmental impact of landfilling the e-plastic and decrease the cost of concrete, making the concrete eco-friendlier. This study aims to deploy a life cycle assessment (LCA) to determine the potential reduction in the environmental impact of e-plastic concrete compared among four scenarios with different types of binders, using SimaPro software. The four scenarios are built up from 1) conventional concrete, 2) concrete with 20 % coarse aggregate replaced by e-plastic, 3) 20 % e-plastic concrete with 30 % cement replaced by GGBS and 4) 20 % e-plastic concrete with 100 % cement replaced by GGBS and fly ash. From the global warming potential (GWP) perspective, using ReCiPe 2016 midpoint (H) analysis, all the e-plastic concrete shows a positive reduction of 1.26 %, 23.8 % and 21.43 % respectively compared to conventional concrete. However, the overall environmental impact shows a negative reduction, especially for scenario 3 and scenario 4. The presence of additives such as superplasticiser and alkaline solvent in the scenario 4 generates an environmental impact to the concrete from their manufacturing process. Therefore scenario 4 has a significant negative reduction in most of the indicators. Practically, e-plastic in concrete helps reduce the consumption of natural resources, lower the construction industry's environmental strain, and fix e-plastic deluged.

The use of recycled concrete aggregates (RCA) for porous asphalts is a viable attempt towards waste management and sustainable conservation of natural resources. Installation of a porous asphalt wearing course is justified in highway pavements because it offers higher skid resistance, glare reduction, lesser traffic noise, reduction of hydroplaning, and mitigation of urban heat island phenomenon. The performance of porous asphalt mixtures containing 0%, 20%, 40%, 60%, 80% and 100% of coarse RCA as replacement for granite was studied and reported in this paper. The mixture containing 0% RCA was used as the control. The skid properties, permeability, water susceptibility and mechanical behaviour of the mixtures under various loading conditions were investigated. Blending granite and RCA in the porous asphalt mixture gave better Indirect Tensile Strength (ITS), rutting resistance, and impact strength indicators. The mixture with 60% RCA achieved desirable results in all tests. It exhibited the best performance based on its ITS and impact strength of 431 kPa and 380 J, respectively. These values were higher than the control by 3% and 30%, respectively. Utilisation of RCA in porous asphalt pavements is recommended based on the results of this study.

Abstract Green building rating tools (GBRTs) are well-known and important instruments for assessing building sustainability. GBRTs constantly upgrade to meet rapid development, one of which is achieving a reasonable balance among the “three pillars” of sustainability, namely, environmental, social and economic sustainability. This study analyzes the changes and trends in the three sustainability pillars of GBRT and reinforces the previous GBRT longitudinal studies in terms of research sample, time span, equal terms, and research depth. Ten global GBRTs are selected by specific screening principles, and a unified criterion framework is presented to compare these selected GBRTs on equal terms. The changes of GBRTs are then analyzed on three levels, namely, categories, subcategories, and criteria. The results show that in the past three decades, there is a continuous decrease in the weight of the environmental category, an obvious increase in the weight of the social category and a little rise in the wight of the “economic” category. “Pollution,” “physical comfort,” and “flexibility” are identified as “sensitive criteria” of environmental, social, and economic categories, respectively, given their significant changes; they are also critical factors for the evolution of GBRT for the past three decades.

Abstract This study aims to analyse the life-cycle assessment of biohydrogen production from palm oil mill effluent (POME) in a pilot-scale up-flow anaerobic sludge blanket fixed-film reactor. The SimaPro LCA software and ReCiPe 2016 impact assessment method were used. Electricity usage was found to be a significant source of environmental impacts, with 50–98% of the total impacts. Furthermore, an improvement analysis was conducted, resulted in a reduction in all impacts, especially global warming impact with 77% reduction from 818 to 189 kg CO2-eq per kg biohydrogen. While shifting the pilot reactor to Sarawak may further lessen the impact to 142 kg CO2-eq due to cleaner grid in that region. Besides, if the environmental burden avoided due to usage of POME is considered, the global warming impact can be further reduced to 54.9 kg CO2-eq. Thus, the pilot reactor has huge potential, especially in utilizing waste to produce bioenergy.

The global municipal solid waste (MSW) generation rate is 2.01 billion metric tonnes annually with an average of 0.74 kg waste/person/day. Approximately 92 % of the MSW originates from organics composition (e.g., food waste; plastic; paper; garden waste/woods, and textile), where 33 % of overall MSW is improperly managed in an efficient and environmentally safe manner. One of the promising methods to solve MSW management issues is to convert MSW into refuse-derived fuel (RDF) that can be used for the clinker burning process in cement kiln to replace the usage of fossil-based solid fuel. Thus, the potential of local MSW composition in energy recovery; suitability of RDF production technology; as well as international-industry requirement on RDF in co-processing and environmental concerns are discussed. Due to heterogeneous composition and sizes in nature, high moisture, and substantial amount of chloride content in MSW, it needs to undergo pre-treatment processes to enhance the RDF’s physio-chemical properties that comply with RDF ASTM/EN standards, where expected high heating value (HHV) is > 20 MJ/kg, ash (<10 %), Chloride (Cl) (<0.80 – 1.00 %), Sulphate (S) (<1.50 %), Nitrate (N) (<1.00 %). As the development of upgraded MSW to RDF is still new in the commercial phase, there is minimal information and data on the techno-economic analysis, as well as recent industrial-scale of thermos-chemical conversion technologies for RDF preparation. Hence, the present work provides a clear picture on overview of municipal solid waste (MSW) generation, MSW composition, MSW pretreatment, and application as co-processing in cement industry are discussed. Besides, recent thermochemical upgrading process (torrefaction, dry carbonization, and hydrothermal carbonization) of MSW from R&D to commercial scale was further highlighted. In summary, this review serves as basic criterion and strategies to explore the new path of upgrading the waste into RDF for the purpose of sustainable energy recovery that adopting in circular carbon economy framework.

Ground granulated blast furnace slag (GGBFS) is a by-product obtained from the iron making process and has suitable properties to be utilized as high volume cement replacement to produce sustainable concrete. This study focuses on investigating the influence of GGBFS replacement level (0%–70%) and water/binder ratio (0.45 and 0.65) on the performance of cement mortar blends. In order to characterize the engineering performance, the compressive strength of the mortar blends was evaluated. Whereas to ascertain the carbon footprint, environmental life cycle assessment was conducted. Besides the compressive strength and carbon footprint, the materials cost for each mortar blends was computed. Based on the compressive strength/carbon footprint ratio analysis, it was found that increased replacement level of GGBFS gave better performance while the cost efficiency analysis shows that suggested GGBFS replacement level of up to 50%. Overall, in considering the strength performance, carbon footprint and materials cost, the recommended GGBFS replacement level for cement blends is 50%. In addition, when the binder content is kept constant, mortar blends with lower water/binder ratio is preferable when considering the same parameters.

This work discusses the palm oil mill processing carried out at Jugra Palm Oil Mill Sdn Bhd, situated at Selangor, Malaysia with the capacity of 45-t fresh fruit bunch (FFB)/h. Typically, oil palm residues and palm oil mill effluent (POME) from FFB are generated while processing. Prior to discharge, POME should be treated to remove pollutants in the effluent. As such, the performances of anaerobic and aerobic ponds were assessed in this study to determine temperature, pH, biological oxygen demand (BOD), sludge volume index (SVI), and dissolved oxygen (DO). From the experiments, mesophilic temperature due to better process stability was applied in anaerobic ponds. The pH results displayed a fluctuating trend between lower control limit and upper control limit, and, the pH value increased from one pond to another. The final discharge BOD and SVI appeared to be lower than 100 mg/L and 10 mL/L indicating low degree of pollution and good settling ability for biomass/solid. DO was dose to normal, mostly below 2 mg/L. The experimental outcomes revealed the effective treatability of POME in adherence to the standard regulation, which is the priority for environmental sustainability within this industry domain.