Environmental Benchmarking Research Articles

Carrying capacity-based benchmarks for Belgian residential buildings

Environmental benchmarks are a means to stimulate lowering environmental impacts of buildings. These benchmarks may be based on a bottom-up or top-down approach. While bottom-up benchmarks are derived from the analysis of reference buildings and represent current building practice, staying within the Earth's carrying capacity requires top-down benchmarks representing long-term environmental goals. Top-down benchmarks are derived by allocating a share of the global carrying capacity to objects, e.g. buildings, using so-called sharing principles. Various sharing principles exist, which significantly influence benchmark values. This study applies a wide range of sharing principles, including novel principles, to define top-down benchmark values for Belgian residential buildings based on global carrying capacities. An environmental budget was first allocated to Belgium, then to households and finally to the housing function. In each step, multiple sharing principles were applied, resulting in 32 combinations of sharing principles. For a single-person household, the minimum and maximum budget resulting from the combinations differ by a factor 42. Based on data availability and quality as well as ethical considerations, the authors of this paper give preference to “right to development” for the allocation to Belgium; “household composition” for the allocation to households and “final consumption expenditures” for the allocation to the housing function. The comparison of the top-down benchmark values with bottom-up benchmarks reveals that various measures are required to remain within the Earth's carrying capacity. The top-down benchmark values presented in this paper can hence guide policymakers in establishing environmental targets and related roadmaps for residential buildings in Belgium.

A concept for non-uniform thermal irradiation emulation in an immersive virtual environment

This study addresses the challenge of emulating human thermal environments without the need to build physical mock-ups. The aim is to complement the established technology of emulating visual environments with head-mounted displays. For the user, the virtual environment (VE) emulates an arbitrary indoor environment including visual and thermal aspects. In contrast to conventional climate chambers, we describe a concept to emulate arbitrary non-uniform environments and room geometries without the need to construct or modify separate physical mock-ups for each scenario being tested. By fully emulating air temperatures as well as the thermal irradiation, a user can experience the same thermal sensation as in the actual environment. An air conditioning system and nine supply air diffusers are used for the air temperature and humidity control. For thermal radiation, 45 temperature-controlled surfaces are arranged in a hemicube around the user. An arbitrary environment’s thermal irradiation is emulated by a projection of temperatures on the hemicube surface elements. This study compares two methods for setting the surface temperatures in the VE to emulate thermal irradiation. Finally, it presents the results of computational fluid dynamic simulations that benchmark the capability of the VE to emulate a non-uniform indoor thermal environment. For the non-uniform thermal environment benchmark scenario, the assumption of a uniform enclosure (using the surface average radiant temperature) resulted in a surface root mean square error of 2.2 K (local deviation of up to 4.6 K) of radiant temperature on the person dummy surface. The projection method was implemented for the VE, utilising temperature-controlled surfaces. Depending on the projection method used to determine the surface temperatures, it was possible to decrease the root mean square error of the radiant temperature in the emulated environment to a range of 0.4 K to 0.7 K.

A parametric approach for developing embodied environmental benchmark values for buildings

PurposeThe production and construction of buildings cause significant environmental impacts besides those arising from their operation. Recently, some European countries have started introducing life cycle assessment as a mandatory calculation method for new buildings, and it is foreseen that by 2030 this will be done in every member state, at first without any legal minimum values.MethodsExtensive databases on the embodied impacts of buildings, which would be needed to support setting the baseline impacts, are still missing. This paper proposes an approach for determining bottom-up reference values. A large building sample is generated describing “technically feasible” new buildings. Instead of analysing a few typical buildings, the main parameters describing a building are determined and the ranges are defined that these parameters typically take. With the variation of these parameters, a large building sample is generated, and the surfaces and built-in material quantities are determined for typical construction solutions to assess environmental performance.Results and discussionThe method is demonstrated by calculating the reference embodied benchmark values for new residential buildings in Hungary. The results show a baseline embodied Global Warming Potential of 9.5–15.5 kg CO2-eq/m2/yr for single-family houses and 9.1–14.3 kg CO2-eq/m2/yr for multi-family houses.ConclusionsThis method is suitable for estimating the environmental impact of typical new buildings in countries where a large pool of real building data is not yet available.

Would really long-only climate-transition strategies in commodities bring lower market risk for sustainable markets in the long run? The Islamic sustainable market versus the global sustainability leaders

By allocating investments towards commodities that align with climate-transition goals, environmentally conscious commodity investment strategies serve to promote and support sustainable markets, channeling capital towards sectors that prioritize environmental sustainability. Through the application of a quantile causality test, which examines the relationship between commodity-based strategies with a climate-transition focus and eco-friendly markets, over the period spanning from May 1, 2013, to May 25, 2023, our findings reveal a bi-directional causality relationship between different themes of sustainable markets and long-only climate-transition strategies in the commodity market across various market conditions. Furthermore, employing a quantile time-frequency connectedness approach allows us to discern that long-only climate-transition strategies in the commodity market exhibit lower long-run total connectedness with responsible and conscious markets compared to the short term. Consequently, these results suggest that transition-oriented strategies for commodities in a climate-conscious world not only mitigate market risk for regenerative markets in the long run but also indicate that different types of global sustainability leaders demonstrate a stronger connectedness with climate-transition strategies in commodities when compared to the Islamic sustainable market across a majority of quantiles and time horizons. In light of these findings, policymakers are urged to prioritize the long-term dimensions of climate-transition strategies in commodity markets by implementing new emission standards and environmental benchmarks. Additionally, the design and implementation of similar long-only climate-transition strategies in other markets would further enhance the long-term effectiveness of climate-conscious markets and foster stronger connections with responsible markets. our study underscores the significance of integrating climate-transition strategies into commodity markets and highlights their role in promoting sustainable and environmentally conscious investment practices. By directing investments towards climate-aligned commodities, policymakers and market participants can contribute to the long-term sustainability of global markets while fostering stronger connections between sustainable markets and climate-transition strategies in commodities.

Measuring the Interprofessional Health of the Pediatric Cardiovascular Operating Room Work Environment.

Pediatric cardiac surgery is complex and has significant risk, requiring interprofessional teamwork for optimal outcomes. Unhealthy work environments have been linked to poor patient outcomes, staff dissatisfaction, and intention to leave. We describe the interprofessional health of pediatric cardiovascular operating room (CVOR) work environments in the United States and the establishment of a healthy work environment (HWE) benchmark score. Utilizing the American Association of Critical Care Nurses Healthy Work Environments Assessment Tool (HWEAT), interprofessional staff from 11 pediatric CVORs were surveyed. Responses were aggregated, summarized, and stratified by role to examine differences. The following phase used an e-Delphi approach to obtain expert consensus on a benchmark target. Across 11 centers, 179 (60%) completed surveys were reviewed. The interprofessional mean HWEAT score was 3.55 (2.65-4.34). Mean scores for each standard were within the "good" range. Participants reported the highest scores for effective decision-making, with a mean of 3.69 (3.00-4.20). Meaningful recognition scored lowest, mean 3.26 (2.33-4.07). When stratified, surgeons reported higher overall HWE scores (M = 3.79, SD = 0.13) than nurses (M = 3.41, SD = 0.19; P = 0.02, two-tailed). The proposed benchmark was 3.50. This is the first time the American Association of Critical Care Nurses HWEAT has been used to describe the interprofessional health of work environments in pediatric CVORs in the United States. The targeted benchmark can support pediatric CVOR improvement strategies. Creating and sustaining an HWE is an interprofessional opportunity to support high-quality patient outcomes and clinical excellence.

Comparative environmental analysis of sugar beet production using a solar-driven robot and conventional systems from a sustainability perspective

In the context of rapid global population growth and climate change, balancing agricultural productivity with environmental sustainability has never been more important. Precision farming technologies, including robotics, are touted as having huge potential to increase farm productivity, reduce energy and resource use and compact soil, while reducing the overall environmental impact of on-farm production. This comprehensive study presents, for the first time, a detailed analysis and environmental benchmarking of two organic sugar beet production (SBP) systems, conventional (CONV) and robotic (RBT), based on field experiments in Lithuanian conditions where a solar-powered robot is integrated into the production system to carry out sowing and weeding operations. In order to reduce the potential environmental impact and to understand the consequences of using the robot in agriculture, a Life Cycle Assessment (LCA) of the entire SBP process up to the factory gate was carried out. The results of the analysis show that the conventional system has higher total GHG emissions than the robotic system, 36.98 and 27.18 kg CO2eq t−1, respectively, with poultry manure being the largest contributor. The higher beet yield in the RBT system, mainly due to effective weed control, resulted in a higher GHG emissions ratio (14.72) and a higher sustainability index (13.72). The LCA results showed that the CONV system had a higher negative environmental impact than the RBT in all eleven environmental impact categories assessed, with the most pronounced difference in the Ozone Depletion (OD) category. Diesel fuel was identified as the most important environmental factor for organically growing sugar beet in all considered impact categories, with the most notable environmental impact (about 94%) in the terrestrial ecotoxicity category in both systems. Normalization of the results showed that marine aquatic ecotoxicity (ME) had the greatest (78%) influence of all exposure categories for both cultivation systems, CONV – 22079.82, and RBT 18121.61 kg 1.4-DBeq per ton of produced sugar beet. The study found that increasing yields and reducing fossil fuel use in organic farming are the two most promising strategies for achieving sustainability and efficiency in food production.

OEBench: Investigating Open Environment Challenges in Real-World Relational Data Streams

How to get insights from relational data streams in a timely manner is a hot research topic. Data streams can present unique challenges, such as distribution drifts, outliers, emerging classes, and changing features, which have recently been described as open environment challenges for machine learning. While existing studies have been done on incremental learning for data streams, their evaluations are mostly conducted with synthetic datasets. Thus, a natural question is how those open environment challenges look like and how existing incremental learning algorithms perform on real-world relational data streams. To fill this gap, we develop an Open Environment Benchmark named OEBench to evaluate open environment challenges in real-world relational data streams. Specifically, we investigate 55 real-world relational data streams and establish that open environment scenarios are indeed widespread, which presents significant challenges for stream learning algorithms. Through benchmarks with existing incremental learning algorithms, we find that increased data quantity may not consistently enhance the model accuracy when applied in open environment scenarios, where machine learning models can be significantly compromised by missing values, distribution drifts, or anomalies in real-world data streams. The current techniques are insufficient in effectively mitigating these challenges brought by open environments. More researches are needed to address real-world open environment challenges. All datasets and code are open-sourced in https://github.com/Xtra-Computing/OEBench.

Environmental benchmarks for the European cement industry

The urgent need to address climate change has pushed Europe to the forefront of environmental legislation initiatives, such as the Environment Action Program (EAP) within the European Green Deal and the disclosure of Environmental Product Declarations (EPDs) in the construction sector. The cement industry plays a vital role in this transition because it is one of the biggest contributors to greenhouse gas emissions worldwide. EPDs have managed to articulate the environmental information flow across different stakeholders, allowing them to incorporate sustainability design practices at the manufacturing, construction, and design levels. However, current EPDs are deterministically disclosed and lack benchmarks, hindering effective comparison and impeding sustainable material development. To address this challenge, the present research introduces a novel Life Cycle Assessment (LCA)-based probabilistic analysis to develop clinker and cement benchmarks. The proposed method incorporates data from industry reports, environmental databases, and EPDs, to generate the stochastic benchmarks. Moreover, a wide range of environmental performance indicators at a national level in Europe are covered, offering a holistic perspective beyond climate change. The results highlight the benefits of using country-specific environmental benchmarks, reducing the standard deviation of results by 2 to 7 times compared to background datasets. The reduction of clinker content proved to reduce 7 to 9 kg CO2eq/t for every 1% reduction in all countries. However, it also increased other indicators depending on the mineral component used as a replacement, underscoring the need for holistic analysis. The research also exposes discrepancies between EPDs and industry-related data, accentuating the need for stochastic information disclosure to enhance reliability and facilitate decision-making by stakeholders. Another significant contribution of this research is the development of an extensive open-access database, providing a reference for future developments regarding sustainable cement and concrete.

Life cycle environmental benchmarks for Flemish dwellings

To reduce the environmental effects caused by building construction and operation, life cycle assessment (LCA) is increasingly applied. In recent years, national building regulations have implemented LCA requirements to support building life cycle impact reduction. A key element in these regulations are environmental benchmarks which allow designers to compare their building designs with reference values. This study aims to develop bottom-up life cycle environmental benchmarks that represent the range of environmental impact results achieved with conventional construction in Flanders, Belgium. For this purpose, the study investigates the potential of using a database of building energy performance calculations. Specifically, this study considers 39 residential buildings identified as representative of the Flemish energy performance of buildings database of 2015–2016, applying modifications to establish scenarios that are still relevant in 2025. The buildings are assessed with the Belgian LCA tool TOTEM to calculate an aggregated environmental score based on the European product environmental footprint (PEF) weighting approach and including 12 main impact categories. In addition to the aggregated score, the climate change (CC) indicator is analysed individually. In view of the benchmarks, variations were applied to the 39 original buildings in terms of heating system and materialisation. The variation in heating system included changing gas boilers to electric heat pumps to comply with upcoming (2025) Flemish building regulations. The variations in building materials included three sets of conventional Flemish building element compositions that were applied to generate a wider spread of impact results as a basis for benchmarks. Benchmark values were derived through a statistical analysis of the 117 modelled variants: a best-practice value (10th percentile), reference value (median) and limit value (90th percentile). For the environmental score, the benchmark values are 86, 107 and 141 millipoints per square meter of gross heated floor area (GHFA) (mPt m−2GHFA), respectively; and for CC, the benchmark values are 844, 1015 and 1284 kg CO2-eq m−2 GHFA. Finally, the study discusses the representativeness, implications and limitations of the final benchmarks and benchmark approach.

Greening the Future: Harnessing ICT, Innovation, Eco-Taxes, and Clean Energy for Sustainable Ecology—Insights from Dynamic Seemingly Unrelated Regression, Continuously Updated Fully Modified, and Continuously Updated Bias-Corrected Models

This research endeavors to investigate the impacts of information and communication technology, green technological innovation, and environmental tax on the attainment of ecological sustainability with advanced panel date estimation for 2001–2019. The results of this study demonstrate a noteworthy inverse relationship between information and communication technology and ecological footprint, suggesting that progress in ICT has the potential to yield positive consequences in terms of ecological restoration and the promotion of environmental sustainability. Furthermore, this study underscores the significance of GTI in mitigating carbon emissions and effectively addressing environmental challenges. The findings indicate that the incorporation of environmentally sustainable technology can yield favorable ecological consequences and make significant contributions towards the attainment of worldwide climate targets. Nevertheless, the study highlights the importance of considering potential rebound effects. It underscores the imperative for ongoing research and the implementation of comprehensive policies within the realm of environmentally sustainable technology. Moreover, the present study elucidates the favorable ramifications of GF on ecological sustainability, underscoring its pivotal contribution in curtailing carbon emissions, augmenting environmental benchmarks, and facilitating the ecological footprint. Enhancing the utilization of green finance, making adjustments to national regulatory frameworks, and achieving harmonization of public financial incentives to bolster sustainable development are important. Additionally, the study posits that the incorporation of ET can catalyze businesses and individuals to embrace environmentally friendly energy sources and sustainable practices, thereby fostering positive outcomes for the environment. The study offers significant insights into the contributions of information and communication technology, green technology innovation, and environmental technology to advancing ecological sustainability. It emphasizes the need for collaborative endeavors among academia, industry, and government to cultivate a supportive ecosystem for sustainable development.

Promoting Climate Resilience in Building Construction Industry in Ghana

This study reports the perspectives of building construction stakeholders on how they are promoting climate resilience. Using descriptive research design with a purposive sampling through online questionnaire and adapted version of Relative Importance Index (RII) on selected environmental benchmarks, the major findings are: a) there is more to be done to promote green construction; b) many stakeholders still hold on to carbon-intensive approach; c) underlying cause for this lack of migration to less carbon use appears to be attitudinal than complete lack of knowledge of climate mitigation; d) many construction firms lack internal management system to monitor climate mitigation benchmarks indices. Based on these findings, recommendation being made is that construction managers may need to link up with international conferences to enhance professional competencies in advanced technologies for mitigating building-related carbon emission, while Government offers subsidies and green construction certification to promote contractors’ awareness of climate resilience in building construction.

Health Risk Assessment and Environmental Benchmark of Cadmium in Farmland Soils around the Gangue Heap of Coal Mine, Chongqing

To analyze the health risk assessment and environmental benchmark of cadmium in farmland soils surrounding the gangue heap of a coal mine in Chongqing, Hakanson, the ecological risk index and health risk assessment were used. Meanwhile, the soil environmental reference value of the regional cultivated land was inverted based on the species sensitive distribution model (SSD). The results showed that the dryland soil was polluted by Cd, with an over-standard rate of 55.8%, and the paddy field soil was polluted by Cd, with an over-standard rate of 31.6%. The corn was polluted by Cd, with an over-standard rate of 4.4%, and the rice was not polluted by Cd. The Hakanson ecological risk index showed that Cd was mainly characterized in soils by high ecological risk and considerable ecological risk. The health risk assessment indicated that Cd presented low non-carcinogenic risk by corn and rice; however, it showed acceptable carcinogenic risk by corn and unacceptable carcinogenic risk by rice in this study. The sensitivity analysis of health risks showed that the content of Cd was the most sensitive. The SSD inversion showed that the reference values for Cd in dryland soil of pH ≤ 5.5, 5.5<pH ≤ 6.5, 6.5<pH ≤ 7.5, and pH>7.5 had HC5 values of 0.491, 0.382, 0.376, and 0.588 mg·kg-1, respectively, and that for Cd in paddy soil had an HC5 value of 0.807 mg·kg-1. The reverse analysis showed that the HC5 of Cd in dryland soil (pH ≤ 7.5) and paddy soil was relatively relaxed and was higher than the soil risk screening values, which showed that the current standard was relatively loose. However, the HC5 of Cd in dryland soil (pH>7.5) was lower than the soil risk screening values, which showed that the current standard was relatively strict. It is suggested that the current soil standard could be adjusted in this area.

Revisiting mass, economic value, quality-based functional units in life cycle assessment of foods towards environmental benchmarking

Revisiting mass, economic value, quality-based functional units in life cycle assessment of foods towards environmental benchmarking

Developing a New Data-Driven LCA Tool at the Urban Scale: The Case of the Embodied Environmental Profile of the Building Sector

Given the ambitious climate reduction targets of the European Commission for the building sector and the adoption of the life cycle assessment method for the environmental metrics, the authors of this research present a new tool that allows for an extensive evaluation of buildings (operational and embodied environmental profile). The tool developed is an engine written in Python that was applied to analyze the buildings of Milan, using several open databases available for the Lombardy region (Northern Italy). Approximately 240,000 building units were investigated and compared using ecoinvent 3.9.1 EN 15804 as a background library and characterization methods in compliance with EN 15978. The tool can establish reliable environmental benchmarks to implement building policies, such as climate footprint limits for new constructions as required by the recast Energy Performance of Buildings Directive (2023). This article shows the embodied impact of construction materials. The results for residential, commercial, and retail building units (old and new) are 15 kg CO2eq/(m2 of net area × year) for the entire building stock (old and new building units) and 21 kg CO2eq/(m2 of net area × year) for new buildings (nearly zero energy building units).

Health Risk Assessment and Environmental Benchmark of Heavy Metals in Cultivated Land in Wanjiang Economic Zone

Focusing on the cultivated land in Wanjiang Economic Zone, 338 sets of soil samples of rice, wheat, and their roots were collected; the concentrations of five heavy metals (As, Cd, Cr, Hg, and Pb) were determined; the soil-crop pollution characteristics were evaluated using the method of geo-accumulation index and comprehensive evaluation; the human health risk of ingesting heavy metals from crops was assessed; and the soil environmental reference value of the regional cultivated land was inverted based on the species sensitive distribution model (SSD). The results showed that in the study area, the soil of rice and wheat was polluted by heavy metals (As, Cd, Cr, Hg, and Pb) in varying degrees, among which Cd was the primary pollution factor of rice, with the over-standard rate of 13.33%, and Cr was the main over-standard factor of wheat, with the over-standard rate of 11.32%. The cumulative index showed that the percentage of Cd pollution in rice was 80.7%, and that in wheat was 35.85%. Contrary to the high pollution level of soil heavy metals, only 17.19% and 7.55% of Cd in rice and wheat exceeded the national food safety limit, and the accumulation capacity of the heavy metal Cd was rice>wheat. The health risk assessment indicated that heavy metals had high non-carcinogenic risk and unacceptable carcinogenic risk to adults and children in this study. The carcinogenic risk of rice intake was higher than that of wheat, and the health risk of children was higher than that of adults. SSD inversion showed that the reference values of As, Cd, Cr, Hg, and Pb in paddy soil in the study area were an HC5 of 6.24, 0.13, 258.27, 0.12, and 53.61 mg·kg-1 and an HC95 of 68.81, 5.71, 1068.92, 0.80, and 174.22 mg·kg-1, respectively. The reference values of As, Cd, Cr, Hg, and Pb in wheat soil HC5 were 32.99, 0.04, 271.14, 0.09, and 47.53 mg·kg-1, and the values of HC95 were 225.28, 0.71, 998.58, 1.43, and 241.99 mg·kg-1, respectively. The reverse analysis showed that the HC5 of heavy metals in rice and wheat were lower than the soil risk screening values in the current standard to varying degrees. The current soil standard had loosened for the evaluation results of this region.

Preliminary study on the use of Big Data for environmental benchmarks of residential buildings in Flanders

Building construction and operation both have a high environmental impact. In Flanders (Belgium), public authorities have defined clear targets for improved building energy performance, but a strategy to reduce construction (embodied) impact is still lacking. Environmental benchmarks based on Life Cycle Assessment (LCA) have been identified as a means to limit embodied impacts. Such benchmarks are often derived with a bottom-up approach consisting of a statistical analysis of the building stock, which is usually modelled based on a limited set of representative buildings or archetypes. In this paper, a data-driven approach is applied based on building data from the Flemish Energy Performance of Buildings (EPB) database. In a recent study, the buildings from the EPB database were clustered based on geometric and energy-related parameters, and for each cluster representative buildings were selected. This resulted in 54 buildings representative of newly built residential buildings in Flanders. The building set distinguishes itself from other existing sets because it was automatically generated from a large building database. Up until now, the EPB building set has only been used to evaluate the financial feasibility of energy performance levels in Flanders. In this preliminary study, an LCA is performed to assess the life cycle environmental impacts of five sample cases in view of benchmarking. The sample includes two detached, two semi-detached, and one terraced house, all solid construction and in line with the Flemish EPB requirements of 2014. The results show that the environmental score of the buildings is comparable to benchmark values obtained based on the analysis of Belgian archetypes. Further, the building geometry and compactness are identified as key parameters, whereas the materialisation has a more limited influence on the environmental impact. Next research steps will focus on the modelling of more cases, including different construction types, energy performance levels, and potential impact mitigation strategies. The study concludes that the EPB buildings are promising to define environmental benchmarks for the Flemish dwelling stock.

Preliminary environmental benchmarks for a new Photonic Meta-Concrete based on state of the art radiative cooling materials

The usage of conventional air-conditioners increased due to global warming and the urban heat-island-effect in cities. These systems are responsible for 7% of global greenhouse gas emissions and 10% of the total energy consumption. Radiative Cooling is a passive cooling strategy which tries to mitigate global warming and the urban heat-island-effect by emitting heat through the atmosphere, into outer space. These materials are already studied for several decades, but for the first time a radiative cooling material is under development based on conventional concrete. In order to evaluate the environmental performance of this newly developed material compared to existing cooling materials, environmental benchmarks need to be defined. To determine such benchmark, existing, state of the art, daytime radiative cooling materials are assessed in this paper. Information on these materials is collected through a literature review. The radiative cooling materials are modelled using the generic Ecoinvent v3.6 database and the environmental impact is assessed using the Belgian LCA method for buildings, i.e. the MMG method. This method is in line with the EN15804:A2 and covers 16 environmental impact categories, such as global warming potential, acidification, eutrophication, water scarcity and toxicity. The results show that the production process of the materials, i.e. thin film deposition techniques, are poorly represented in the Ecoinvent database. Assumptions and adaptations are made based on literature and experts’ feedback. A sensitivity analysis is carried out to gain insight in the uncertainty of the assumptions made. Based on the results, preliminary environmental benchmarks are generated and the environmental impact of the first composition of the photonic meta-concrete is assessed against these benchmarks.

Assessment of thermal and environmental benchmarking of a solar dryer as a pilot zero-emission drying technology

Food drying is a highly energy intensive process and therefore significantly contribute to carbon emission. Although solar air dryers are considered renewable, they are not fully emission free as conventional energy from grid is required to run the fan or blower. The solar air efficiency as well as fan power requirements are influenced by the mass flow rate of air, and therefore flow rate is essential parameter for evaluating solar air dryer performance in terms of thermal, drying and environmental parameters. It is essential to develop a framework to evaluate critical mass flow rate by considering the optimum thermal, drying, and environmental performance for benchmarking of zero-emission solar air dryer. However, such a framework is currently lacking. To address this issue, a novel study was conducted using V-groove double pass solar air heater (SAH) to experimentally analyse thermal, drying and environmental parameters to develop a methodology for zero emission solar air dryers based on critical flow rate for fan power consumption. The experiments were conducted at five different flow rates (0.021, 0.031, 0.041, 0.051, and 0.061 kgs−1). The maximum thermal efficiency achieved was 74.89% at 0.061 kgs−1. However, the average COP, average exergy efficiency, moisture ratio, and CO2 mitigation had optimum results at 0.041 kg/s mass flow rate as fan power consumption was reduced by 16% compared to 0.061 kgs−1. The critical flow rate evaluation is useful for predicting and minimising power consumption and progress towards zero emission system by using photovoltaics in future systems. The successful implementation of the proposed method can substantially contribute to the industrialisation and cutting of emissions of solar air heaters for drying applications.

Off-shore and On-shore Macroalgae Cultivation and Wild Harvesting: an LCA-based Evaluation from Baltic Case Studies

Seaweeds are organisms with unique characteristics. They contain a broad spectrum of micro and macro elements (i.e., minerals, carbohydrates, proteins, lipids, pigments, and vitamins). Furthermore, they have a very high growth rate and are present in large quantities and species in nature. Therefore, they represent an ideal feedstock for a biorefinery concept. Historically, macroalgae used in biorefineries have been harvested directly from the sea or the shores (off-shore technique). However, recent studies are analysing the possibility of creating on-shore cultivation facilities. This research aims to perform a Life Cycle Assessment (LCA) study that analyses and compares the environmental impact of two seaweed cultivation and wild harvesting techniques in the Baltic conditions based on existing pre-commercial and commercial projects. Inventory data are collected directly from two macroalgae producers in the Baltic Sea region (one wild harvester and one on-shore), integrated with literature, and then normalized to the selected functional unit, i.e., 1 ton of harvested fresh macroalgae. The results, implemented with SimaPro 9.4 software, determine which of the two techniques has the highest environmental impact and which are the most sensitive environmental indicators. Furthermore, the results underline the critical parameters for the two cultivations (i.e., fuel consumption and electricity), contributing to identifying environmental benchmarks for further optimization strategies. The alternative scenarios analysis included in the study aims to explore and highlight the effect of the variation of selected input parameters or assumptions to provide a consistent assessment of the uncertainty of the model outputs and the main findings in terms of environmental impacts.

Rules Mining-Based Gene Expression Programming for the Multi-Skill Resource Constrained Project Scheduling Problem

The multi-skill resource-constrained project scheduling problem (MS-RCPSP) is a significant management science problem that extends from the resource-constrained project scheduling problem (RCPSP) and is integrated with a real project and production environment. To solve MS-RCPSP, it is an efficient method to use dispatching rules combined with a parallel scheduling mechanism to generate a scheduling scheme. This paper proposes an improved gene expression programming (IGEP) approach to explore newly dispatching rules that can broadly solve MS-RCPSP. A new backward traversal decoding mechanism, and several neighborhood operators are applied in IGEP. The backward traversal decoding mechanism dramatically reduces the space complexity in the decoding process, and improves the algorithm’s performance. Several neighborhood operators improve the exploration of the potential search space. The experiment takes the intelligent multi-objective project scheduling environment (iMOPSE) benchmark dataset as the training set and testing set of IGEP. Ten newly dispatching rules are discovered and extracted by IGEP, and eight out of ten are superior to other typical dispatching rules.