Xuexiu Jia

The efficient use of waste heat (WH) from gas streams is one of the key aspects in reducing the energy intensity, operating costs, and environmental impact of production processes and in the transition to sustainable energy. However, in many practical cases, the use of WH remained challenging due to the specific limiting conditions of the stream and critical issues such as fouling and the corresponding low heat transfer efficiencies. In particular, particle fouling hinders the operation of heat transfer equipment (HTE) and introduces several design considerations. To tackle this issue at the design stage, this study proposed a systematic framework intended for the design of fouling-resistant HTE. For a given usable stream, the major elements of the HTE design framework include (i) the Environmental assessment that enables the user to select the optimal way of WH utilization; (ii) a mobile testing device (MTD) for fouling parameters measurement, and (iii) an improved mathematical model for determining the critical fouling rate for the design of THE suited to particle-laden streams. The framework, especially the mobile testing device and the mathematical model, is tested under laboratory and/or industrial conditions, and illustrated with a case study of the WH stream with cement powder. Results show that the environmental assessment module can guide the selection of optimal usage with minimum environmental impact, and the mobile testing device and the mathematical model are able to determine the critical fouling velocity to support HTE design with higher resistance to fouling and higher operational reliability.

With the rising demand for renewable hydrogen as an alternative sustainable fuel, efficient transport strategies have become essential, particularly for regional and small-scale applications. While most previous studies focus on the long-distance transport of hydrogen, little attention has been given to the application in regions that are remote from major transmission infrastructure. This study evaluates the techno-economic performance of hydrogen road transport using multiple-element hydrogen gas containers and compares it with multimodal transport using rail. The comparison is performed for the southeastern region of the Czech Republic. The comprehensive techno-economic assessment incorporates detailed technical evaluations, precise fuel and energy consumption calculations, and real-world infrastructure planning to enhance accuracy. Results showed that multimodal transport of hydrogen can significantly reduce the cost for distances exceeding 90 km. The cost is calculated based on annual vehicle utilization, assuming the remaining utilization will be allocated to other tasks throughout the year. However, the cost-effectiveness of rail transportation is influenced by track capacity limits and possible delays. Additionally, this study highlights the crucial role of regional logistics hubs in optimizing transport modes, further reducing costs and improving efficiency.

With the rising demand for renewable hydrogen as an alternative sustainable fuel, efficient transport strategies have become essential, particularly for regional and small-scale applications. While most previous studies focus on long-distance transport of hydrogen, little attention has been given to the application in regions that are remote from major transmission infrastructure. This study evaluates the techno-economic performance of hydrogen road transport using multiple-element hydrogen gas containers and compares it with multimodal transport using rail. The comparison is performed for southeastern region of the Czech Republic. The comprehensive techno-economic assessment incorporates detailed technical evaluations, precise fuel and energy consumption calculations, and real-world infrastructure planning to enhance accuracy. Results showed that multimodal transport of hydrogen can significantly reduce the cost for distances exceeding 90 km. The cost is calculated based on annual vehicle utilization, assuming the remaining utilization will be allocated to other tasks throughout the year. However, the cost-effectiveness of rail transportation is influenced by track capacity limits and possible delays. Additionally, this study highlights the crucial role of regional logistics hubs in optimizing transport modes, further reducing cost and improving efficiency.

With the development of human society, the urban population and the urban building stock have been continuously increasing. Environmental issues such as greenhouse gases emissions, air pollution, and construction waste have gradually emerged. Due to the lack of an urban functional area database, it is very time-consuming to manually identify building functional areas. As a result, most of the current research on urban building functions are estimated at a large regional scale or only detailed calculations of individual buildings. The building functions classification method needs to be further improved. Based on the traditional methods, this paper proposes a building function classification method with higher recognition accuracy and is less time-consuming. The method is then applied to a certain area of Chaoyang District, Beijing, for validation and verification. The results show that the urban building function classification method in this paper has a recognition rate of 96.18%, an overall classification accuracy of 94.37%, and a kappa coefficient of 0.9089. The classification results are in good agreement with the virtual interpretation. In addition, automatic classification of building functions is implemented using ArcPy in ArcGIS, which significantly improves the classification efficiency.

The increasing issue of water quality degradation has affected the availability of water. The consideration of water quality is becoming more important for water minimisation. There is a need to integrate water quality into the current water assessment framework. This study tries to involve the water quality into the widely used water footprint assessment framework in order to quantify the water usability changes during the water use process. Based on water footprint concepts from international standard ISO 14046, water availability is further interpreted to emphasize the impact of water quality on the usability. An effective water availability footprint is defined as the quantitative and qualitative extent of a certain body of water which meets the needs of a certain purpose of water use. A water quality index is proposed to quantify the contribution of water quality on water availability, and two approaches of calculating water quality index are discussed, in order to explore the possibility of involving water quality into the water availability footprint assessment. Based on the definitions and framework, a case study is conducted to illustrate the features of this framework, and 3 outflows with different water quality are set to discuss the impact of different water quality profiles on the calculation of water availability footprint. It shows that water quality profiles can have a remarkable influence on the calculation. For the case with an outflow of F2-1, the water availability footprints with minimum water quality index, average water quality index and the volumetric water footprints as 1,600 m 3 , 1,277 m 3 , and 1,000 m 3. This indicator can determine the consumptive water use and also quantify the exploitation of water quality. The involvement of water quality regarding multiple contaminants in water footprint assessment should be further investigated in future studies.