Comprehensive Economic Benefits Research Articles

A Novel Day-Ahead Optimization-Oriented Low-Carbon Economic Scheduling Scheme for Integrated Energy Systems

As the global energy structure undergoes transformation and the low-carbon development process continues to advance, integrated energy systems have progressively emerged as crucial technical support for achieving sustainable development. In this paper, a joint-day optimal scheduling model is put forward considering the existence of dispatchable resources in community integrated energy systems (CIES). The aim is to cut down the system operation cost and enhance energy utilization efficiency. This model is founded on the concept of energy hubs and combines the shiftable, transferable, and reducible characteristics of demand-side flexible loads. It includes gas turbine power generation systems, energy storage, as well as wind and solar renewable resources. System operation cost and carbon trading cost are comprehensively taken into account, and ultimately, the CIES low-carbon economic dispatch model with the lowest total cost as the optimization objective is established. The Yalmip toolbox and Cplex solver are employed to solve the model. The optimization results of flexible electric and thermal loads participating in dispatching under different scenarios are analyzed through simulation. The economic benefits of electric and thermal independent dispatching are compared and analyzed, and the economic benefits of electric and thermal coupled dispatching are verified. The study reveals that the rational scheduling of user-side flexible loads can notably reduce operating costs, lower the load peak-to-valley difference and carbon emissions, and boost the comprehensive economic and environmental benefits of the system.

Economic Effects Assessment of Forest City Construction: Empirical Evidence from the County-Level Areas in China

Forests are both an irreplaceable natural resource and a vital economic asset for all humankind. Based on the data of counties in mainland China from 2007 to 2020, the article explores the direct impact and spatial spillover effects of the policy implementation on the economic growth of counties with the help of the forest city pilot policy and the policy evaluation model. The results reveal that policy implementation can have a positive economic growth effect on the pilot counties, which, in turn, can significantly increase the size of the county′s GDP, the level of GDP per capita, and the total amount of nighttime lighting brightness. The implementation of forest city construction can bring about 2.74% of total GDP size, about 2.63% of per capita GDP development level, and about 7.25% of nighttime light brightness to the county on average. Cost–benefit analysis also indicates that forest city construction can bring about a comprehensive economic benefit of approximately CNY 686.453 million (approximately USD 96.82 million) to the counties. The rapid improvement in labor productivity, significant influx of high-end factors, and continuous expansion of market potential are important mechanisms through which policy implementation promotes economic growth in pilot counties. While promoting economic growth in the pilot counties, forest city construction can also have positive spatial spillover effects on neighboring areas in the pilot counties. Furthermore, when the deficits in atmospheric vapor pressure and annual evapotranspiration are used as instrumental variables for forest city construction, the empirical estimates are not significantly altered. In the process of building forest cities, county governments should be wary of issues such as the high cost of forest maintenance. This study provides a Chinese model and policy reference for other countries and regions in the world to deal with the relationship between forest city construction and county economic growth.

Multiphase time-varying batch process monitoring based on stage moving model migration

To improve product qualities and obtain maximum comprehensive economic benefits from batch process production, it is of great practical significance to optimize the operation of batch production processes. Considering the multiphase and slow time-varying characteristics, a multiphase time-varying batch process monitoring method is proposed based on stage moving model migration technology. Firstly, the sliding windows are constructed with moving phases, where the moving of different phases is decided by the influence of the process variables to the final product. And time slices are the basic units for building the regression models. Secondly, to analyze and capture the relationship between the process variables of both the old mode and new mode and the final quality variable, the JY-PLS algorithm is utilized on each time slice within sliding windows for quality prediction. Then, monitoring indexes and corresponding control limits are calculated and used for process monitoring. The application to a real multiphase time-varying batch process, the start-up process of injection molding process, proved the effectiveness of the proposed method.

Effects of chemical regulation on the growth, yield and fiber quality of cotton varieties with different plant architectures

Chemical regulation has beneficial effects on the growth, yield, and fiber quality of cotton with different plant architectures. This study aimed to investigate the combined effects of chemical regulators such as mepiquat chloride (1,1-dimethyl-piperidiniuchloride, DPC), chlormequat chloride (CCC), thidiazuron (TDZ), and ethephon (ETH) during the growth period of cotton. Different combinations of chemical regulators were applied to examine the growth, development, yield, and quality of cotton. The results showed that the application of different chemical regulators had varying effects on the yields of the two cotton varieties with distinct plant architecture. Specifically, K1C1 (before and after topping with 1:1 25% DPC, 50% TDZ, and 40% ETH) and K2C2 (before topping with 25% DPC and after topping with 50% CCC, 50% TDZ, and 40% ETH) were sprayed on ‘Wankemian-1’ and ‘Wanmian-191’, thereby increasing the cotton yield. The K2C2 treatment increased the upper half mean length and fiber strength of the two varieties but decreased the fiber length uniformity index. The fiber strength, fiber length uniformity index, and spinning consistency index of ‘Wankemian-1’ were higher than those of ‘Wanmian-191’. Based on comprehensive yield, quality, and economic benefits, K1C1 and K2C2 were determined to be the most effective chemical regulators of ‘Wankemian-1’ and ‘Wanmian-191’, respectively.

Optimization of scale inhibitor and adsorption enhancer during squeeze process in offshore oilfields

To solve the problem that scale in oilfields can lead to a reduction of formation permeability and blockage of wellbore and production system pipelines, through the scale inhibitor-formation water compatibility experiment and the minimum effective scale inhibitor concentration experiment, three different types of surfactants are selected as adsorption promoters. Three different types of surfactants were selected as adsorption–desorption accelerators through dynamic core adsorption–desorption experiments. The results of the indoor experiment show that the three types of scale prevention agents selected can meet the environmental protection requirements of the sea area. The static scale prevention rate at high temperature (>120 °C) exceeds 80%, and the minimum effective concentration is less than 3.5 mg L−1. The preferred cation Gemini surfactant has a stable adsorption enhancement effect of the scale inhibitor under different water-bearing conditions and can effectively extend the squeezing life under complex formation conditions. The results improve the comprehensive economic benefits of the field and provide technical feasibility to significantly improve the scale prevention efficiency of the field.

Impacts of land-use change on the habitat suitability and connectivity of giant panda

Land-use changes lead to habitat loss and fragmentation, which poses a further threat to the survival of species. Therefore, it is crucial to analyze how land-use change affects its habitat. 37 counties in Sichuan Province, China, where giant pandas are distributed, were selected as the subjects. Through analyzing land-use change, habitat suitability and connectivity characteristics over the past 20 years, and establishing a correlation between them, the impacts of land-use change on the habitat suitability and connectivity of giant pandas were explained. The results showed that from 2000 to 2020, the different land-use areas in the study area showed a pattern of change with an increase in forest area, built-up area and water area, and a decrease in grassland area and cropland area. There were significant differences in the characteristics of land-use dynamics changes among counties. Changes in land-use dynamics have a significant impact on the habitat suitability and connectivity of giant pandas, which is manifested in the fact that the conversion of forestland to grassland and grassland to cultivated land significantly reduces habitat suitability, while the conversion of grassland to forestland and cultivated to forestland significantly increases the connectivity of giant panda habitats. Changes in the habitat suitability index were significantly and positively correlated with the land-use dynamics index and the land-use degree index. Our findings emphasize the importance of balancing socio-economic development, land-use, and conservation efforts to maintain giant panda habitat. Therefore, the development of rational land-use patterns in future management is key to maximizing the comprehensive social, economic and ecological benefits.

GS-DeepLabV3+: A mountain tea disease segmentation network based on improved shuffle attention and gated multidimensional feature extraction

The prevention and control of Camellia Oleifera diseases can produce significantly comprehensive economic benefits. And precisely identifying the types of diseases on oil tea leaves can enhance the effectiveness of pest and disease control. Currently, the most effective deep learning methods for segmentation are suffering from the challenges such as indistinct disease spots on the actual oil tea leaves that are difficult to differentiate from the background, the high similarities in characteristics between different diseases, and the small target area of disease regions that are easily ignored. In this paper, GS-DeepLabV3+ network is proposed, which is an improvement upon DeepLabV3+ and aims to effectively enhance disease identification and segmentation rates. Initially, a gated pyramid feature fusion structure is proposed, utilizing a special module to merge features of different dimensions to enhance differentiation of similar features. Secondly, an improved grouped attention fusion mechanism is introduced, which allocates channel and spatial weights to different feature groups, enhancing the extraction of detailed features. Lastly, we substituted the backbone network of DeepLabV3+ with the more lightweight MobileNetV2, which significantly reduces the number of parameters while more stably extracting multidimensional features. In comparison with the existing segmentation networks on a self-created oil tea leaf disease data set, GS-DeepLabV3+ achieved a mIoU of 87.77% and an average pixel accuracy of 94.55%. Compared to the base DeepLabV3+ network, there was a 4.14% improvement in mIoU, a 3.58% increase in mPA, and a 1.4% rise in precision. The improved attention mechanism contributed to a 1.98% increase in mIoU, and the gated multidimensional fusion mechanism resulted in a 1.03% improvement. These enhancements can provide technical references for crop protection and pest disease segmentation.

Improved soil moisture, nutrients, and economic benefits using plastic mulchs in balsa-based agroforestry systems.

The manufacture of wind turbine blades generally uses balsa wood as the base materials, and it is crucial to explore new regions for cultivating balsa trees to achieve carbon neutrality in the future. Xishuangbanna may be China's only area with a tropical climate suitable for the large-scale planting of balsa trees. The present study investigated the key soil elements influencing the growth of balsa plantations and the effects of different cultivation practices on soil environments and economic benefits in Xishuangbanna, China. We found that the height of balsa stems after growing 4years reached 5.8m; the increment of diameter at breast height (DBH) reached 27.7cm and volume of balsa stems reached 196.0 m3ha-1 in Xishuangbanna of China. It is of the utmost importance to improve the contents of soil exchangeable magnesium (Mg) and available phosphorus (P) for the growth of balsa trees, and exchangeable aluminium (Al) inhibited the growth of balsa trees. The practice of plastic film mulching not only improved soil moisture in the 40‒100-cm soil layer in the dry season and in the 0-60-cm soil layer in the rainy season but also enhanced soil nitrate nitrogen when compared with no plastic-mulching practice in balsa plantations. The comprehensive economic benefits of balsa/coriander/ginger/taro plantations were significantly improved by implementing plastic film mulching, as compared to balsa plantations. We conclude that balsa tree can be cultivated in Xishuangbanna, China, and its successful cultivation provides opportunities for China's wind power development.

CNT supported Sm/Co-LDH for antimony adsorption and subsequent application in supercapacitor to prevent secondary pollution

Currently, the recycling of spent adsorbents stands as a significant concern, primarily due to the inherent value of these resources. Opting to repurpose these materials in the realm of energy storage not only alleviates environmental pressures but also offers a compelling alternative for combating the energy crisis. This multifaceted approach not only contributes to environmental sustainability but also yields invaluable electrode materials, thereby delivering comprehensive economic benefits. In this study, a novel fCNT-Sm/Co-LDH was synthesized via hydrothermal route which efficiently adsorbed antimony (Sb(III)) from wastewater. The expended adsorbent was reused for energy storage, mitigating secondary pollution. The fCNT-Sm/Co-LDH presented the maximum removal efficiency of 96 % at 10 mg/L of initial concentration of Sb(III) at pH 8. The Sb-enriched waste adsorbent (fCNT-Sm/Co-LDH@SbOx) was further employed as an energy storage device and demonstrated outstanding performance. The electrochemical examination unveiled that the fCNT-Sm/Co-LDH@SbOx showcased the most substantial specific capacitances, reaching 850 F/g at 2 A/g. The fabricated fCNT-Sm/Co-LDH@SbOx-based symmetric supercapacitor device displayed 78 Wh/kg of energy density at 833 W/kg of power density while unveiling capacitance retention of 92 % after 10,000 cycles. This research presents an efficient method for recycling used adsorbents, which can be extended to enhance eco-friendly and cost-effective reprocessing of other hazardous solid wastes, particularly for energy storage applications.

Root spatial distribution and belowground competition in an apple/ryegrass agroforestry system

CONTEXTForestry and fruit industry is a unique and advantageous industry in Xinjiang, China, and it is an important channel for farmers to increase income. With limited land resources and a shortage of forage in southern Xinjiang, farmers began to establish a fruit-grass interplanting model to improve the comprehensive economic benefits of orchards. OBJECTIVEThe objective of this study was to explore the effects of apple/ryegrass intercropping system on root spatial distribution and competition, and to evaluate the performance of field microclimate, soil physical properties and productivity under intercropping. METHODSIn the study, three different planting patterns were designed: sole-cropped apple (The spacing of the rows of apple trees was 4.0 m, and the plant spacing was 1.0 m), sole-cropped ryegrass (Strip sowing, row spacing was 0.25 m), and apple/ryegrass intercropping (The distance from apple row to ryegrass row was 1.0 m). Two-year field experiments were conducted to measure the root length density (RLD), specific root length (SRL), interspecific competitiveness index, soil moisture content, organic matter content, air temperature, relative humidity, wind speed, yield, land equivalent ratio (LER) and aggressivity. RESULTS AND CONCLUSIONCompared with sole cropping, intercropping reduced the RLD of apple and ryegrass and increased the SRL of ryegrass. The competition space between apple and ryegrass was concentrated in the soil area of 100 cm horizontally and 0–20 cm vertically, and apple was more competitive than ryegrass. Intercropping increased the content of soil moisture and organic matter and improved the microclimate of farmland, decreased the air temperature, increased the relative humidity of an orchard, and decreased wind speed. Although intercropping reduced ryegrass and apple yield, land equivalent ratio (LER) was 1.27–1.30, indicating that intercropping improved land use efficiency. Root competition led to an uneven distribution of root length density (RLD) and specific root length (SRL). The plasticity of root morphology and root spatial distribution was key to adapting to competition and maximizing the absorption of water and nutrients in apple/ryegrass agroforestry systems. SIGNIFICANCEApple/ryegrass intercropping system maximizes resource utilization and reduces interspecies resource competition. It improved land use efficiency, improved the comprehensive benefits of fruit and grass production.

Innovation driver and county air pollution: cost-benefit analysis perspective.

Innovation is the first power to drive the county's green and low-carbon. It is crucial to explore the impact of innovation on air pollution from the perspective of counties at the bottom of the administrative division hierarchy. The article is aimed at exploring the direct impact effects, spatial spillover effects, impact mechanism pathways, non-linear relationships, and cost-benefits of innovation drive on air pollution in counties. To this end, based on the collection of county-level data from 2007 to 2020 in mainland China, the article constructs a fixed-effects model, a dynamic panel model, and a spatial Durbin model for analysis. For every 1% increase in the quantity of innovation, the county SO2 emission concentration decreases by 0.2% on average; for every 1% increase in the quality of innovation, the county SO2 emission concentration decreases by 0.3% on average. When the county innovation quantity driver increases by one standard deviation, the county SO2 concentration decreases by an average of 0.29%; when the county innovation quality driver each standard deviation increases, the county SO2 concentration is reduced by 0.33% on average. The significant entry of high-end factors, the increased frequency of regulation by the environmental protection department, and the increasing efficiency of energy use are the important mechanism pathways for innovation-driven reduction of air pollution in counties. There is no significant "(inverted) U-shaped" relationship between innovation-driven air pollution in the county samples. There is a negative spatial spillover effect of the innovation quality drive on air pollution control in all Chinese county samples. Innovation to drive the declining size of the county's sulfur dioxide can bring about one billion yuan (about 139.81 million U.S. dollars) in comprehensive economic benefits. In the coming period, county governments should build a new pattern of "blue sky and white clouds" with neighboring regions in terms of spatial agglomeration of high-end elements, green transformation and utilization of energy, and intelligent monitoring and supervision of pollution.

Coarse synthetic fibers (PP and POM) as a replacement to steel fibers in UHPC: Tensile behavior, environmental and economic assessment

Ultra-high performance concrete (UHPC) has excellent compressive strength and ductility. Nevertheless, the extensive utilization of UHPC has been impeded by factors including the exorbitant cost, substantial carbon emissions, and vulnerability to corrosion associated with steel fibers. This study explores an innovative approach by introducing polypropylene fibers (PPF) and polyoxymethylene fibers (POMF) as replacements for steel fibers (SF) in the preparation of hybrid fiber-reinforced ultra-high-performance concrete (HUHPC), with a total fiber content of 3% vol. The influence and mechanism of different PPF/POMF replacement ratios for SF on the flowability, compressive performance, and tensile behavior of HUHPC were investigated. An axial tensile static constitutive model for HUHPC considering the PPF/POMF replacement ratio was established, and a comprehensive environmental benefit assessment index and economic benefit assessment index considering mechanical performance were proposed. The results showed that using PPF and POMF with low modulus as replacements for high-modulus SF significantly improved the flowability of HUHPC. Notwithstanding there is a decrease in compressive and tensile strength of HUHPC resulting from the utilization of low-modulus and low-strength PPF and POMF as substitutes for SF, it modified the axial tensile stress-strain behavior of conventional UHPC and notably improved its tensile toughness. The established axial constitutive model for HUHPC in this study effectively predicted the tensile stress-strain behavior of HUHPC. Importantly, the comprehensive environmental assessment index reveals that HUHPC offers superior environmental and economic benefits compared to traditional UHPC, leading to substantial cost reductions. The development of HUHPC through fiber hybridization presents a promising strategy for the low-carbon and cost-effective production of UHPC, holding significant implications for the broader adoption and application of UHPC.

Negative Ecological Impacts of Wind Power, Hydropower and Geothermal Energy

With the rapid development of the global economy and increasing population, the demand for energy is growing. Clean energy technology has received a lot of attention in recent years, and it has solved the traditional energy sources such as coal and oil to a great extent, but it still has some negative effects on the environment. This paper obtains data on ecosystems from authoritative websites and published papers in various countries. Use these data to show the changes in the ecological environment before and after the development of clean energy. It has been found that wind power could reduce environmental pollution and water consumption. However, it causes visual interference, noise pollution and negative impacts on wildlife. Hydropower stations generally have comprehensive economic benefits such as flood control, navigation, aquaculture, landscaping and tourism. However, large reservoirs cause extensive inundation upstream of the dam and also affect plant-side aquatic ecosystems. The main environmental problems in the development of geothermal energy are the emission of toxic gases, the overuse of water resources, the negative impact of heavy metals on agriculture and the inefficient use of geothermal energy. In order to minimize the environmental problems associated with the development of various energy sources, it is hoped that the government will support the development of scientific and technological innovations through policies that regulate the development of energy sources.

Comparative Analysis of Leaf Vegetable Productivity, Quality, and Profitability among Different Cultivation Modes: A Case Study

In recent years, vegetable production has been in the transitional stage from traditional cultivation mode to modern cultivation mode. Therefore, evaluating the actual productivity and economic benefits of different cultivation modes is instructive for leafy vegetable production. This research chose a vegetable production company (Shanghai, China) as a demonstration case to cultivate various leaf vegetables under different cultivation modes (hydroponic, substrate, and soil cultivation). By investigating the yield and quality of vegetables, as well as all production costs and selling prices, we drive a comparative evaluation of comprehensive features and economic benefits of different cultivation modes. The results showed that leafy vegetables cultivated by hydroponic mode gain the highest fresh weight at the early growth stage, but the greatest unit yield (0.98~1.21 kg·m−2) emerged under the soil cultivation mode. Vegetables grown under substrate mode had the best comprehensive quality with high soluble solids content and low nitrate content. The unit costs of the soilless cultivation modes (8.26~10.3 CNY·m−2) were 3–4-fold higher than that of soil cultivation, mainly due to the high fixed costs and input costs, especially for substrate mode. According to actual prices, the soil cultivation mode had the highest economic benefits as a whole (4.83~8.83 CNY·m−2), and only hydroponic cabbage which had comparable yield gained considerable benefits (8.94 CNY·m−2). Quality-based pricing scheme can make substrate mode achieve profitability. The pricing scheme that guarantees a 40% revenue is within acceptable limits for consumers. Based on this actual production case, it can be concluded that a low unit yield of hydroponic mode and a high unit cost of substrate mode are the predominant factors affecting their profitability and economic viability.

Peak shaving auxiliary service analysis for the photovoltaic and concentrating solar power hybrid system under the planning-dispatch optimization framework

Concentrating solar power (CSP), being one of the key stakeholders in the peak shaving auxiliary service (AS) market, possesses distinct advantages due to its characteristics of energy storage, sustainability, and adjustability. Nevertheless, the market mechanism for CSP in the peak shaving AS is still in its nascent stage, particularly in the northwest region of China where thermal power dominates and there are bundled large-scale photovoltaic developments. Exploring strategies to capitalize on the peak shaving benefits of CSP, mitigate system operation costs, and enhance the revenue generation of CSP entities has emerged as a prominent area of research. This study establishes a planning-dispatch double-layer optimization model. Two mechanisms respectively based on the unit load rate (ULR) and peak shaving contribution (PSC) are proposed and examined, and the bidding range and quotation range for peak shaving of CSP under the two mechanisms are suggested according to the cost of the peak shaving capacity of CSP. The proposed model is analyzed using the improved IEEE 30-bus system. The results show that the capacity ratio of photovoltaic and CSP determines the functional position of CSP. Optimizing TES capacity and installed capacity of PV power can maximize the peak shaving capacity of CSP, while simultaneously reducing the peak shaving demand on thermal power plants, power system dispatching costs, and the LCOE of the CSP–PV hybrid system. The comprehensive economic benefit of the hybrid system increases by 2.93% under the PSC-based mechanism than that under the ULR-based mechanism. In comparison to the nonpeak shaving case under the ULR-based mechanism, the CSP–PV hybrid system exhibited a 3.74% increase in net revenue in the high peak shaving demand scenario. Furthermore, the comprehensive economic benefit of the CSP–PV hybrid system improved by 3.80% over the full life cycle, while the PV curtailment experienced a 2.50% decrease.

Thoughts on the development of CO2-EGR under the background of carbon peak and carbon neutrality

In September 2020, the Chinese government proposed the goals to reach carbon dioxide emissions peak by 2030 and achieve carbon neutrality by 2060 (“two-carbon goals”). This brings opportunities to the development and application of CO2-enhanced gas recovery (CO2-EGR) in China. To obtain an overall understanding of the development of CO2-EGR under the two-carbon goals, this paper analyzes the significance, potential, status quo and challenges of CO2-EGR, and makes suggestions on the development of CO2-EGR in China. The research results are obtained as follows. First, the development of CO2-EGR plays a crucial role in ensuring China's energy security, accelerating the construction of the clean energy system to promote energy transition and realizing the two-carbon goals as early as possible. Second, China should clarify a path for CO2-EGR development, build a spatial layout of CO2-EGR, and promote digital inclusion in CO2-EGR, enhance the emission reduction role of CO2-EGR in the multi-energy complementary system, boost large scale application of renewable energy and deep decarbonization in the traditional coal industry, which is difficult to reduce carbon emissions. Third, China should draw lessons from European and American tax credit and innovation funds policies to accelerate the construction of a CO2-EGR policy support system. Fourth, China should carry out research on key CO2-EGR technologies to accelerate the construction of a CO2-EGR methodology and standard system and promote rapid and standardized development of the CO2-EGR industry. It is suggested to establish a CO2-EGR demonstration area in the Sichuan Basin and popularize it across China, so as to improve comprehensive economic benefits through the establishment of large-scale industrial clusters. It is concluded that the two-carbon goals bring opportunities to the development of CO2-EGR in China, which will promote gas production and demonstration of CO2 sequestration in gas reservoirs and have positive significance in ensuring energy security and realizing carbon peak and carbon neutrality in China.

Retracted: Multi-objective grasshopper optimization algorithm for optimal energy scheduling by considering heat as integrated demand response

Due to the challenges associated with grid management, it is crucial to develop energy management systems that consider optimal resource performance within an integrated system and enable control of power exchange with the grid. Simultaneously, addressing the demand for multiple energy sources is a critical step towards achieving an economically and efficiently integrated energy system (IES), which plays a pivotal role in promoting sustainable IES development. Building upon these considerations, this article proposes a two-objective optimization model that incorporates the concept of demand response and integrated energy systems, while considering comprehensive economic and energy efficiency benefits. To ensure realism, a range of linear and nonlinear constraints are employed. To address such a problem, a two-stage modeling and solution approach is proposed. Initially, flexible electrical and thermal loads are combined to establish a mechanism for effectively responding to system behavior. Subsequently, a multi-objective model is presented to enhance energy generation and transfer efficiency, taking into account both demand response and economic aspects. Given the distinct properties of these objectives, a multi-objective grasshopper optimization algorithm (GOA) is developed. The Pareto concept is utilized to enhance search performance, and fuzzy theory is employed to select the optimal solution from the set of solutions. Finally, the proposed model and algorithm are evaluated under various operating conditions on the studied system. The results demonstrate that this model effectively improves economic aspects, enhances efficiency, and reduces pollutant emissions to an acceptable level.

Study on solar-driven methanol steam reforming process in parabolic trough solar receiver-reactors by developing an optical-thermal-chemical model of realistic porosity distributions

The catalyst particle packing characteristics have a significant impact on improving the comprehensive energy conversion performance and economic benefits of sustainable solar-driven thermochemical hydrogen production systems. However, corresponding accurate and efficient numerical research tools or methods still need to be developed. In this paper, a three-dimensional comprehensive optical-thermal-chemical coupling model with catalyst particle packing characteristics is proposed for the parabolic trough solar receiver-reactor (PTSRR) of methanol steam reforming reaction (MSRR) for hydrogen production. This model is developed by combining a Monte Carlo ray tracing optical model, a computational fluid dynamics model, a MSRR comprehensive kinetic model with a Blender rigid body packing model. After validation, it was found from comparisons with previous studies that this model can represent relatively realistic catalyst porosity distributions of packed-bed reactors at a very low computational cost. Then, this model was applied to obtain the porosity of different PTSRR-MSRRs and optimize the catalyst size and shape, to achieve better comprehensive performance as well as economic benefits of higher overall efficiency and catalyst utilization efficiency. The results reveal that the PTSRR-MSRRs filled with cylinders and Raschig rings (R-PTSRR) can achieve similar high methanol conversion rate, while the R-PTSRR has more advantages with its lower average resistance coefficient and CO selectivity. After weighing the methanol conversion rate, the overall efficiency and the catalyst utilization efficiency, the optimum R-PTSRR is highly recommended. This study provides a useful option for rapid comprehensive analysis and optimization of similar solar-driven thermochemical conversion processes on catalyst particle packed beds.

Techno-economic evaluation and environmental benefit of hybrid evaporative cooling system in hot-humid regions

Reducing the energy consumption of buildings is of great importance to achieve carbon neutrality targets. The air conditioning (AC) system in buildings, as a large energy consumer, should be taken into account as one of the main building service systems for energy saving integrated with energy-efficient and environmental-friendly technologies. Indirect evaporative cooler (IEC), constrained by its cooling principle, originally exerts energy saving potential in hot-arid regions. Recently, progress has been made in expanding its application to hot-humid regions. However, due to the large cooling load in hot-humid regions, an IEC-integrated hybrid system should be developed as an improved solution to effectively save energy and maintain the indoor thermal comfort. In view of the lack of a complete hybrid IEC system being reported thus far, in this study, the IEC is combined with a cooling coil unit as a primary air handling unit (IEC-PAU) for fresh air handling and supply. Accordingly, the model of the IEC-PAU with indoor fan coil units (FCUs) is constructed and incorporated into a typical office building, and the results are compared with a baseline case under hot-humid climate conditions. Comprehensive energy, economic, and environmental benefits are analyzed considering different setpoint temperatures in typical cities of the Great Bay area (GBA) of China. Results show that the proposed system could reduce the energy consumption of 4.6 kWh/m2 on average, with the acceptable thermal comfort level as they are in the reference cases. The greatest energy saving ratio is 8.3%, while the performance of the proposed system declines under the higher setpoint temperature. The saved electricity expenses can lead to the average discounted payback period of 8.2 years in the GBA cities. Furthermore, an annual greenhouse gas emission of 4.8 t on average can be diminished. In summary, this work demonstrates the feasibility of the hybrid IEC system as an effective approach for energy saving in hot-humid regions, which is promising to prompt the carbon neutrality in China.

Design and research of environmentally friendly field sewage purification mechanical device

Abstract The shortage of water resources has become a serious constraint to the sustainable development of the country’s economy and society. The environmentally friendly field sewage purification device is one of the effective ways to reduce water pollution and solve the water shortage problem. In this paper, the RBF-purification model is used as a calculation tool to study the economic feasibility of the environmentally friendly field sewage purification machinery and its equipment maintenance. The calculation results show that the distance benefit of field sewage purification is 13%. The benefit share of comprehensive economic benefit is the highest, 41%. The share of environmental benefits is 39%. The professionalism of the equipment users has the highest percentage of the problems that need to be maintained in the field wastewater purification equipment, at 54%. The percentage of equipment operation and management was 27%. The smallest percentage is for equipment maintenance with 19%.