Anping Wan

The poor heat transfer performance of LiBr solution is one of the main obstacles to improving the performance of absorption cooling systems. In this study, the combined effects of the heat transfer enhancement and pressure loss increment of LiBr solution-based nanofluids in plate heat exchangers are investigated theoretically. First, a correlation for predicting the Nusselt number of the LiBr solution in a chevron plate heat exchanger with different chevron angles is developed based on the experimental data, and the prediction error is in the range of−3.8% to 6.0%. Second, the heat transfer coefficients and friction factors of Al₂O₃ nanofluid and MWCNT nanofluid are numerically calculated. The nanofluids have higher heat transfer rates than the LiBr solution. The heat transfer enhancement of the nanofluid in the 30°Chevron type plate heat exchanger is similar to that in the 60°Chevron type plate heat exchanger. The Nusselt number and heat transfer coefficient of the Al₂O₃ nanofluid with a 2.5% volume fraction are about 2.2% and 9% higher than those of the LiBr solution. The Nusselt number and heat transfer coefficient of the MWCNT nanofluid with 0.05% volume fraction are about 7.8% and 8.1% higher than those of the LiBr solution. The friction factor increases with the rising nanofluid volume fraction because the viscosity increases. When the nanofluid volume fractions are one-third and two-thirds of the equivalent value, the performance coefficient improvement of MWCNT nanofluid is about two to four times higher than that of the Al₂O₃ nanofluid. When the volume fraction is one-third of the equivalent value, the performance coefficient improvement of Al₂O₃ is about 30% to 40% higher than that of the MWCNT nanofluid. When the volume fraction of MWCNT nanofluid is between 0.01% vol. and 0.02% vol. and that of Al₂O₃ nanofluid is between 1% vol. and 1.5% vol. the heat transfer performance and economic performance of the two nanofluids can be regarded as equivalent. Finally, the appropriate selections of LiBr-solution based nanofluids for different application requirements are presented.

In an effort to address the load adjustment time in the thermal and electrical load distribution of thermal power plant units, we propose an optimal load distribution method based on load prediction among multiple units in thermal power plants. The proposed method utilizes optimization by attention to fine-tune a deep convolutional long-short-term memory network (CNN-LSTM-A) model for accurately predicting the heat supply load of two 30 MW extraction back pressure units. First, the inherent relationship between the heat supply load and thermal power plant unit parameters is qualitatively analyzed, and the influencing factors of the power load are screened based on a data-driven analysis. Then, a mathematical model for load distribution optimization is established by analyzing and fitting the unit’s energy consumption characteristic curves on the boiler and turbine sides. Subsequently, by using a randomly chosen operating point as an example, a genetic algorithm is used to optimize the distribution of thermal and electrical loads among the units. The results showed that the combined deep learning model has a high prediction accuracy, with a mean absolute percentage error (MAPE) of less than 1.3%. By predicting heat supply load variations, the preparedness for load adjustments is done in advance. At the same time, this helps reduce the real-time load adjustment response time while enhancing the unit load’s overall competitiveness. After that, the genetic algorithm optimizes the load distribution, and the overall steam consumption rate from power generation on the turbine side is reduced by 0.488 t/MWh. Consequently, the coal consumption rate of steam generation on the boiler side decreases by 0.197 kg (coal)/t (steam). These described changes can greatly increase the power plant’s revenue by CNY 6.2673 million per year. The thermal power plant used in this case study is in Zhejiang Province, China.

The rapid pace of innovations and the frequency of replacement of electrical and electronic equipment has made waste printed circuit boards (WPCB) one of the fastest growing waste streams. The frequency of replacement of equipment can be caused by a limited time of proper functioning and increasing malfunctions. Resource utilization of WPCBs have become some of the most profitable companies in the recycling industry. To facilitate WPCB recycling, several advanced technologies such as pyrometallurgy, hydrometallurgy and biometallurgy have been developed. Bioleaching uses naturally occurring microorganisms and their metabolic products to recover valuable metals, which is a promising technology due to its cost-effectiveness, environmental friendliness, and sustainability. However, there is sparse comprehensive research on WPCB bioleaching. Therefore, in this work, a short review was conducted from the perspective of potential microorganisms, bioleaching mechanisms and parameter optimization. Perspectives on future research directions are also discussed.

By using exhaust gas as heating source, a combined cycle power plant with inlet fuel heating is investigated experimentally. Energy analysis and exergy analysis are carried out under different power load and ambient temperature. The results reveal that the thermal efficiency of the power plant system increases as power load increases. The thermal efficiency and power output at 5°C are 54.15% and 412 MW, respectively; while when the ambient temperature is 35°C, the thermal efficiency and power output are 52.3% and 330 MW, respectively. Under the same conditions, the combustion chamber has the highest irreversibility rate, while the air compressor has the lowest. The irreversibility rate of the power plant system increases in line with power load. The second-law efficiency increases from 37.08% to 50.12% when the power load changes from 30% to 100%.

Modeling the penetration process in soft tissue simulant is the basis for evaluating the damaging efficiency of projectiles. To investigate the penetration dynamics of fragments in gelatin, this paper presented a model describing both the penetration resistance and the temporary cavity dynamics. The modeling process was set up using the law of energy conversion and conservation. The equations for the movement of the penetrator and the movement of the target medium are closely combined through sharing the same set of parameters. Penetration experiments were conducted using fragments of two different shapes: cylinder and rhombus. By comparing with the experimental results, the parameters in the present model were estimated and discussed thoroughly. The present model can predict the movement of the penetrator and the cavity expansion in the target with satisfactory accuracy.

Sustainable architectural education is offered in colleges and universities all over the world. Studies have emphasized the importance of sustainable architectural education in introductory courses of architecture major programs, but methods and strategies for teaching sustainable architecture at lower levels are scarce. This study focuses on the design-to-physical-construction process and creates a teaching framework that incorporates the concept of sustainable development from the perspectives of sustainable economy, environment and society. Based on the teaching method of learning through the design-to-physical-construction process and referring to the grounded theory, a case study on a bamboo construction project was conducted to explore approaches and strategies of sustainable architectural education in introductory courses. Results reveal that five systems, including the system of sustainable development, consist of a framework that illustrated the teaching effects. Based on the framework, we discovered five factors that should be considered in incorporating the concept of sustainable development into architectural design teaching, including the necessity of conducting sustainable architectural education in introductory courses. This study helps explore the potential role sustainability plays in incorporating interdisciplinary knowledge, connecting specialized knowledge across different program levels, and motivating student learning. It also provides a reference for the practice of sustainable architectural education.