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The operating temperature of the novel bifacial concentrated photovoltaic-solar thermoelectric generator (PV-STEG) system is a decisive factor in determining the working performance. In this study, a mini-channel heat sink with superior heat transfer characteristics is selected to preserve the lower operating temperature of the PV cell and create sufficient temperature differences for the STEG unit. To settle the related problems, a three-dimensional numerical model is developed. Moreover, the conventional PV system is used as a reference configuration for comparative evaluation. The impact of adopting various flow channel shapes, input solar irradiance, Reynolds number, and inlet temperature is thoroughly explored. The obtained results suggested that the square mini-channel heat sink is more suitable. Furthermore, to maximize the power yield of the system, stronger solar irradiance, higher Reynolds number, and lower inlet temperature is recommended. Besides, the influence of employing diverse nanofluids is also analyzed. The outcomes indicated that the average PV temperature and power output could be significantly reduced/improved by utilizing nanofluids. Specifically, the total efficiency rose by 14.59% compared to the PV alone and PV-STEG systems using single-walled carbon nanotube (SWCNT) nanofluid. Besides, an enhancement of 23.21% in exergy efficiency was obtained compared to the sole PV system. [ABSTRACT FROM AUTHOR]

Lithocholic acid (LCA)-induced cholestasis was accompanied by the occurrence of apoptosis, which indicated that anti-apoptosis was a therapeutic strategy for primary biliary cholangitis (PBC). As an agonist of (Farnesoid X receptor) FXR, we supposed that the hepatoprotection of Obeticholic acid (OCA) against cholestatic liver injury is related to anti-apoptosis beside of the bile acids (BAs) regulation. Herein, we explored the non-metabolic regulating mechanism of OCA for resisting LCA-induced cholestatic liver injury via anti-apoptosis. LCA-induced cholestatic liver injury mice were pretreated with OCA to evaluate its hepatoprotective effect and mechanism. Biochemical and pathological indicators were used to detect the protective effect of OCA on LCA-induced cholestatic liver injury. The bile acids (BAs) profile in serum was detected by LC-MS/MS. Hepatocyte BAs metabolism, apoptosis and inflammation related genes and proteins alteration were investigated by biochemical determination. OCA improved LCA-induced cholestasis and hepatic apoptosis in mice. The BA profile in serum was changed by OCA mainly manifested as a reduction of taurine-conjugated bile acids, which was due to the upregulation of FXR-related bile acid efflux transporters bile salt export pump (BSEP), multi-drug resistant associated protein 2 (MRP2), MRP3 and multi-drug resistance 3 (MDR3). Apoptosis related proteins cleaved caspase-3, cleaved caspase-8 and cleaved PARP were obviously reduced after OCA treatment. OCA improved LCA-induced cholestatic liver injury via FXR-induced exogenous cell apoptosis, which will provide new evidence for the application of OCA to ameliorate PBC in clinical. [Display omitted] • OCA increased the expression of bile acid efflux transporters to resist LCA-induced cholestasis. • OCA inhibited LCA-induced hepatocytic exogenous apoptosis. • OCA activated FXR to inhibit caspase 8 cleaved to ameliorate LCA-induced cholestatic liver injury. [ABSTRACT FROM AUTHOR]

Harvesting energy from the sun is a promising technology to resolve the ongoing energy crisis. Solar photovoltaic (PV) and photovoltaic/thermal (PV/T) systems are mainstream solar energy conversion technologies that enable duple functions to obtain both electrical and thermal energy. However, in practice, emerging problems (uneven temperature distribution, limited cooling effect, freezing issues, high initial costs, etc.) have hindered the development and progress of these technologies. To overcome the aforementioned barriers, a heat pipe was introduced as an effective heat transfer device with passive operation characteristics. The assimilation of cutting-edge thermoelectric (TE), phase change material (PCM) and the development of integrated photovoltaic (BIPV), heat pump, and nanotechnologies have also been explored to achieve higher overall efficiency. This paper focuses on the integration of various heat pipes with solar PV systems and innovative technologies from historical development and recent advancements. In addition, the major observations and challenges are highlighted, and the prospects for future development are corroborated. This work is dedicated to opening new horizons and providing suggestions in this research field, enabling in-depth and broad exploration. • Heat pipes based solar photovoltaic and photovoltaic/thermal systems are reviewed. • The combination of innovative technologies in these systems is summarized. • Using heat pipes in these systems leads to enhanced performance. • Challenges and future suggestions of such technologies are discussed. [ABSTRACT FROM AUTHOR]

The utilization of PCM in PV-TEG system could lead positive effect. However, the system's performance may vary with the insertion position of the PCM, especially in transient and non-uniform conditions. Hence, to narrow the knowledge gap of this issue, a detailed 3D transient model is established in this study using finite element solution. The temperature-dependent properties of thermoelectric materials and the natural convective flow of the melting PCM is regarded to reduce the deviation from the reality. The influence of the PCM height and insertion position of the PCM in PV-TEG system is analyzed. Furthermore, a comparative analysis is also performed to compare the performance of the considered layouts under the uniform and non-uniform radiation conditions. The obtained results show that the increment of the PCM height leads to higher comprehensive performance in PV-TEG-PCM system, the maximum conversion efficiency difference could reach up to 1%. In addition, the PV-PCM-TEG system possesses a higher overall performance in comparison with the PV-TEG-PCM system, and the maximum PV temperature reduction of 19.22 K is observed. Moreover, an increased power of 0.23 W and 0.33 W in PV-TEG-PCM and PV-PCM-TEG systems is obtained compared with the non-uniform illumination conditions. [ABSTRACT FROM AUTHOR]

The dependable and efficient thermal regulation technology for combined photovoltaic-solar thermoelectric generator (PV-STEG) system is of great importance to ensure output performance. To enhance the electrical behavior of PV-STEG system, a passive evaporative cooling (PEC) technique was presented in this work. Some critical parameters such as solar concentration ratio, ambient temperature, relative humidity, air velocity, and water layer thickness were discussed in detail for a comprehensive assessment of the influence on system temperature, electricity production, and energy conversion efficiency. The obtained findings suggested that adopting PEC technology may greatly lower the operating temperature of the PV-STEG system when compared to the uncooled PV-STEG system. At the solar concentration ratio of 5, the maximum temperature reduction of 92.09 K can be achieved with the assistance of PEC technology. Furthermore, the system performance is greatly influenced by ambient conditions. For example, if the system is exposed to lower ambient temperature, lower relative humidity, and higher air velocity, it produces more electrical power. In addition, compared with other factors, the impact of the water layer thickness is quite gentle, and the temperature difference is less than 1 K. However, there also exists an optimal water layer thickness, and the specific value is 1 mm when the solar concentration ratio is 3. Moreover, compared to traditional passive fin cooling technology, this system demonstrates superior performance. • A passive evaporative cooling strategy is developed to cool down PV-STEG system. • The influence of various ambient parameters is investigated. • A 3D numerical model is established to explore the distribution of various fields. [ABSTRACT FROM AUTHOR]

• Comparative study of simultaneously analyzing various solar power generation systems is conducted. • The operation factors of solar radiation, ambient temperature, and condenser side temperature are investigated. • Nanofluid-heat pipe considering the real flow situation is introduced as the heat dissipator. • The performance of the mentioned solar power generation systems is discussed from energy and exergy points. In recent years, photovoltaic modules and solar thermoelectric generator units have been widely used as energy conversion setups in solar power generation systems. However, the output performance may vary depending on the combination forms. Furthermore, thermal management of such systems is critical to ensuring conversion efficiency and long-term stability. The flat heat pipe is a highly efficient passive cooling device with an excellent heat transfer coefficient across extended ranges and no parasitic energy consumption. A comparative analysis is performed in this work to investigate the various configurations (photovoltaic system, solar thermoelectric generator system, bifacial-photovoltaic-solar thermoelectric generator system, tandem-photovoltaic-solar thermoelectric generator system) that use flat heat pipe as a heat sink. The effects of various solar irradiance, ambient temperature, and condenser side temperature on total energy and exergy efficiency are investigated. The results demonstrate that the bifacial-photovoltaic-solar thermoelectric generator system outperforms the other systems in terms of electrical power output yet, the solar thermoelectric generator system has the largest improvement potential due to its low conversion efficiency. When the solar irradiance is 10000 W/m2, the ambient temperature is 298.15 K, and the condenser side temperature is 298.15 K, the power output for the bifacial-photovoltaic-solar thermoelectric generator system can reach up to 1.82 W, whereas the values for the photovoltaic system, solar thermoelectric generator system, and tandem-photovoltaic-solar thermoelectric generator system are 1.54 W, 0.31 W, and 1.45 W, respectively. Furthermore, the influence of utilizing a 5% volume concentration of Ag-nanofluid and pure water as the flat heat pipe working fluid is addressed. The obtained findings show the effectiveness of using nanofluid to improve energy and exergy performance. [ABSTRACT FROM AUTHOR]

Liquid desiccant air conditioning system (LDAS) was considered a promising air conditioning system due to the advantages of low-grade heat utilization, effective humidity control and environment-friendly. The performance of LDAS significantly depends on the heat and mass transfer components, namely dehumidifier and regenerator, while the regeneration process of traditional regenerator is energy-inefficient. Inspired by the high-efficiency solar interfacial evaporation which can produce drinking water from seawater, this method was introduced in this work for liquid desiccant regeneration to overcome the inefficiency of the regeneration process. Wood was prepared as the regenerator by alkali-assisted method and surface carbonization. The regeneration performance of solar interfacial regeneration was experimentally investigated and compared with that of packed-bed tower regeneration and membrane distillation regeneration. Results show solar interfacial regeneration is very competitive due to the high regeneration rate and efficiency, which can reach 0.57 kg m−2 h−1 and 42.5% for 40% LiCl solution under 1-sun irradiation. Moreover, the low temperature rises of concentrated solution, cheap construction costs and operating costs make LDAS more energy-saving. This work is expected to supply a novel method for liquid desiccant regeneration. • A novel regeneration method based on solar interfacial evaporation was studied. • Regeneration efficiency (42.5%) was achieved for 40 wt% LiCl solution under 1-sun. • Diluted solution can be regenerated with a low temperature rise. • Excellent salt-rejecting is conducive to improving regeneration performance. [ABSTRACT FROM AUTHOR]

• Flat plate heat pipe is introduced as heat sink in hybrid photovoltaic-thermoelectric generator system. • Comparative analysis between the bifacial and the conventional tandem photovoltaic-thermoelectric generator system is conducted. • Influence of different solar concentration ratios, convective heat transfer coefficients, external load resistances and working fluids is investigated. • A maximum increase of 20.98% in power output and 14.05% in electrical efficiency is observed for the bifacial system. The conventional tandem photovoltaic-thermoelectric generator (PV-TEG) system has proved the feasibility of solar full-spectrum utilization technology. Nevertheless, the inconsistent operating temperature range for PV and TEG impedes the development of this technique. Hence, to tackle the challenge of mismatch operating temperature issues, a developed bifacial PV-TEG system combined with flat plate heat pipe (FPHP) is proposed in this study. A 3D numerical model has been built to make a comparative analysis between the bifacial FPHP-PV-TEG system and the conventional tandem FPHP-PV-TEG system. The influences of solar concentration ratio, convective heat transfer coefficient, external load resistance, different working fluids on the output power and conversion efficiency are analyzed. The obtained results indicate that the comprehensive performance of the proposed bifacial FPHP-PV-TEG system is superior to that of the conventional tandem FPHP-PV-TEG system. An increase of 20.98% and 14.05% in overall power generation and energy conversion efficiency could be achieved in bifacial FPHP-PV-TEG system compared with tandem FPHP-PV-TEG system, when the solar concentration ratio is 6 and the convective heat transfer coefficient is 1200 W/m2/K. Moreover, the behavior of the two systems could be enhanced by increasing the solar concentration ratio and the convective heat transfer coefficient. Besides, using water as working medium exhibits the best performance followed by ethanol and acetone in the bifacial FPHP-PV-TEG system, while the variation of working medium in tandem FPHP-PV-TEG system could be almost neglected. [ABSTRACT FROM AUTHOR]