Thermoelectric air disinfection system

Epidemic viruses seriously affect human health and the normal operation of society, so it is particularly important to effectively kill viruses. In this work, a thermoelectric air disinfection system is studied. Utilizing the characteristics of semiconductor thermoelectric sheets with both cold and hot ends, the system can simultaneously sterilize the air by heating and reduce the temperature of the air by cooling. The measurement results show that the air temperature can be increased to 80 ℃ for disinfection, and then cooled to 35 ℃, and the total energy utilization rate of the system can reach up to 1.2. In addition, combined with the measurement results and numerical calculations, the parameters such as the number of thermoelectric element series, input power, air flow, and boundary insulation can be used to analyze their effects on the system performance. The system has broad potential applications in public health, medical care, and household disinfection. © 2022 中国物理学会 Chinese Physical Society.

Phase-Change Material Design for Thermoelectric Generator-Assisted Building Integrated Photovoltaic

As the coronavirus pandemic has brought about global economic recession and reduction in greenhouse gas emissions, energy efficient building retrofitting has become a comprehensive solution to increase the employment rate and reduce the energy consumption of buildings. This situation requires more energy-efficient integrated generation systems. In this study, an integrated generation system is proposedfor building integrated photovoltaic, thermoelectric generator, and phase change material as an enhanced generation system for buildings. In the proposed system, the phase change material absorbs solar radiation as latent heat within the melting temperature, increasing the photovoltaic conversion efficiency. Additionally, the thermoelectric generator harvests additional electricity as the temperature difference is maintained during the phase change. The total generated energy of the proposed system highly depends on the melting temperature and thickness of the phase change material. Therefore, the appropriate melting temperature and thickness design conditions of the phase change material were derived with the following simulations based on transient energy balance equations in 12 daily profiles. As a result, the optimal melting temperature increased by 5.4°F (3.6°C) and 1.9°F (1.04°C) with an insolation increase of 317 Btu/ft2 (1000 Wh/m2) and a 1.8°F (1°C) increase in ambient temperature, respectively. In addition, the optimal thickness increased by 0.04 in (2.5 mm) with an insolation increase of 317 Btu/ft2 (1000 Wh/m2).

Early fever detection on COVID-19 infection using thermoelectric module generators

In 2020 the COVID-19 pandemic has suddenly stopped society and changed human interaction. In this work, a thermoelectric generator wearable device for early fever detection symptoms is presented as a possible solution to avoid higher propagation of this disease. To identify a possible fever symptom, numerical and parametric simulations are developed using a highquality-refined hexahedral mesh. At first, a 2-pair-leg thermoelectric module has undergone simulations to establish temperature conditions, open-circuit voltage, and power output generation;and secondly, these previous results are extrapolated for a larger thermoelectric module containing 28 pair-leg of N-P type material. The numerical study shows that a maximum value of electrical power of 60.70 mW was reached for 28-pair-leg N-P type thermocouples under a constant temperature difference of 20 K.

CO2 Reduction Potential from Efficiency Improvements in China’s Coal-Fired Thermal Power Generation: A Combined Approach of Metafrontier DEA and LMDI

Among the G20 countries, China is the only country to experience an increase in electricity generation from coal-fired thermal power plants from 2019 to 2020. This study aims to develop an analytical framework combining metafrontier data envelopment analysis with the logarithmic mean Divisia index for a detailed decomposition analysis of ‘mass-based’ energy-related CO2 reduction potential through efficiency improvements in coal-fired thermal power plants in China. The results show that inefficiency in power generation can be largely attributed to differences in the location of power plants and the production scale. Moreover, the impact of regional heterogeneity on the changes in power generation efficiency is more notable for the small–medium power plants in the northeast region than the large power plants in the western region in China. However, when focusing on the mass-based CO2 reduction potential associated with the regional heterogeneity, its positive effects in the western region for the large power plants are 6.2 times larger than that in the northeast region for the small–medium power plants. These results imply that an analysis that focuses only on the efficiency score would ignore the production scale of coal-fired thermal power plants and thus would fail to properly evaluate the environmental impacts associated with efficiency changes.