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With the proposal of China's dual-carbon goal, the recovery of industrial waste heat (IWH) for district heating has gained increasing attention. Recently, some scholars have proposed that combined heat and water (CHW) systems are more economical compared with separate heat and water supplies. Beijing lacks desalinated water (DW) and clean low-carbon heat, whereas Tangshan in Hebei Province is rich in IWH. By combining CHW with seasonal thermal energy storage, a case of long-distance transport of hot DW from Tangshan to Beijing was planned, and the costs, energy consumption, and feasibility were analyzed. As a result, under the optimal heat source temperature and effect number of 70 °C and 10 for seawater desalination, the heat from various IWH sources of the three costal steel plants is recovered maximally to produce about 35000 t/h of 95 °C DW. Then, the hot DW is transported to Beijing with a long-distance heat loss ratio controlled below 3 %. Annually, 271.2 million tons of DW and 91.5 million GJ of heat is supplied. The introduction of IWH can save 2.68 billion Nm3 of natural gas per year and the discounted payback period is about 10 years, which has obvious energy-saving, environmental, and economic benefits. • Industrial waste heat is recovered for combined heat and water supply. • Annual utilization of waste heat from three iron and steel plants is maximized. • Thermal economic analysis of combined heat and water system is carried. • Economic long-distance transport radius reaches 200 km. • Seasonal thermal storage plays a dual role in heat storage and peak shaving. [ABSTRACT FROM AUTHOR]

Coal separation based on computer vision has attracted substantial attention in recent years. However, developing reliable object detection models relies on large-scale annotated dataset, which in industrial practice is time-consuming and labor-intensive to obtain. In this paper, we propose a novel data augmentation model called dual attention deep convolutional generative adversarial network (DADCGAN) to expand dataset scale and improve object detection. For the first time, the proposed DADCGAN, which adopts DCGAN as its foundation architecture, introduces efficient channel attention and external attention mechanisms to capture essential feature information from the channel and spatial dimensions of images, respectively. Moreover, spectral normalization and two time-scale update rule strategies are incorporated to stabilize the training process. The implementation of our proposed data augmentation strategy includes two steps. First, traditional pixel transformation is used to expand an original small dataset. Then, our GAN-based data augmentation is executed to further expand the dataset by generating synthetic images. Experimental results show that our DADCGAN model achieves the lowest FID value, decreasing the FID by 21.30–71.96 % compared to other baseline GAN models, showcasing its ability to produce more realistic coal-gangue images. Finally, the data augmentation strategies are applied to the YOLOv4 model, enhancing the mAP by 9.26 %, highlighting its significance in enhancing coal-gangue object detection. These results have important implications for the development and implementation of computer vision-based technologies, enabling the realization of cleaner and more efficient coal separation methods. • Propose GAN-based data augmentation to generate synthetic coal-gangue images. • Apply efficient channel and external attention to capture key features of images. • Use spectrum normalization and imbalanced learning rate to stabilize GAN training. • Produce more realistic images using DADCGAN with lower FID than regular GAN models. • Improve coal-gangue detection accuracy with our data augmentation strategies. [ABSTRACT FROM AUTHOR]

The combined heat and water (CHW) system has been studied by many scholars since it was proposed, and a project has been implemented in Shandong, China in 2021. However, there have been few studies on optimization and comparisons of cases on the heat source side of CHW. Taking a coal-fired thermal power plant as an example, through the reasonable matching of steam flows and analysis of thermal economic parameters, the effect number and heat source steam temperature of a multi-effect distillation (MED) + multi-stage flash (MSF) combined heat and water production (CHWP) system were optimized. The optimal MED heat source temperature was found to be 70 °C, and the optimal MED and MSF effect numbers were 10 and 5, respectively. Finally, the waste heat in the power plant was utilized as much as possible throughout the year. Compared with two cases of the separate heat and water production (SHWP) system, the CHWP system easily achieved better water quality and economy under the condition of almost equal exergy efficiency, and it was easier to realize than the first case of the SHWP system. • Effect number and heat source temperature of desalination process are optimized. • Thermal economic analysis of combined heat and water production system is carried. • Annual utilization of waste heat from a thermal power plant is maximized. • Seasonal matching problem of the system is discussed and tried to be solved. [ABSTRACT FROM AUTHOR]

With increasing urbanization in China, many areas are facing a shortage of clean heat sources. To this end, numerous scholars have proposed the use of nuclear energy for heating. However, nuclear power plants are generally located far from urban areas. Some have proposed a combined heat and water (CHW) system that uses water from the water supply system as a heat carrier to provide heat to urban areas without the need for a return water pipeline. In this study, the Jiaodong Peninsula, which lacks freshwater and clean heat sources, is considered as a CHW system example, and the comparison with other traditional heating schemes, as well as the application prospects of the nuclear CHW system, are analyzed and discussed. The CHW transformation is planned using four AP1000 units of the Haiyang Nuclear Power (HYNP), which can supply 591 million tons of water and 74 million GJ of heat annually, satisfying 38% and 72% of the demand in the supply area, respectively. Compared with other traditional heating schemes, the HYNP CHW scheme in the Jiaodong Peninsula has social, environmental, and economic benefits. • Combined heat and water (CHW) system can alleviate water and heat shortages. • A CHW system is technically and economically feasible in the Jiaodong Peninsula. • A CHW system for nuclear district heating can realize emission reduction. [ABSTRACT FROM AUTHOR]