scholarly journals The Optimized Design of a NPC Three-Level Inverter Forced-Air Cooling System Based on Dynamic Power-loss Calculations of the Maximum Power-Loss Range

2016 ◽  
Vol 16 (4) ◽  
pp. 1598-1611 ◽  
Author(s):  
Shi-Zhou Xu ◽  
Feng-You He
2021 ◽  
Vol 09 (03) ◽  
pp. E482-E486
Author(s):  
Stanislas Chaussade ◽  
Einas Abou Ali ◽  
Rachel Hallit ◽  
Arthur Belle ◽  
Maximilien Barret ◽  
...  

Abstract Background and study aims The role that air circulation through a gastrointestinal endoscopy system plays in airborne transmission of microorganisms has never been investigated. The aim of this study was to explore the potential risk of transmission and potential improvements in the system. Methods We investigated and described air circulation into gastrointestinal endoscopes from Fujifilm, Olympus, and Pentax. Results The light source box contains a lamp, either Xenon or LED. The temperature of the light is high and is regulated by a forced-air cooling system to maintain a stable temperature in the middle of the box. The air used by the forced-air cooling system is sucked from the closed environment of the patient through an aeration port, located close to the light source and evacuated out of the box by one or two ventilators. No filter exists to avoid dispersion of particles outside the processor box. The light source box also contains an insufflation air pump. The air is sucked from the light source box through one or two holes in the air pump and pushed from the air pump into the air pipe of the endoscope through a plastic tube. Because the air pump does not have a dedicated HEPA filter, transmission of microorganisms cannot be excluded. Conclusions Changes are necessary to prevent airborne transmission. Exclusive use of an external CO2 pump and wrapping the endoscope platform with a plastic film will limit scatter of microorganisms. In the era of pandemic virus with airborne transmission, improvements in gastrointestinal ventilation systems are necessary to avoid contamination of patients and health care workers.


Author(s):  
Hiroyuki Yamazaki ◽  
Yoshiaki Nishimura ◽  
Masahiro Abe ◽  
Kazumasa Takata ◽  
Satoshi Hada ◽  
...  

Tohoku Electric Power Company, Inc. (Tohoku-EPCO) has been adopting cutting-edge gas turbines for gas turbine combined cycle (GTCC) power plants to contribute for reduction of energy consumption, and making a continuous effort to study the next generation gas turbines to further improve GTCC power plants efficiency and flexibility. Tohoku-EPCO and Mitsubishi Hitachi Power Systems, Ltd (MHPS) developed “forced air cooling system” as a brand-new combustor cooling system for the next generation GTCC system in a collaborative project. The forced air cooling system can be applied to gas turbines with a turbine inlet temperature (TIT) of 1600deg.C or more by controlling the cooling air temperature and the amount of cooling air. Recently, the forced air cooling system verification test has been completed successfully at a demonstration power plant located within MHPS Takasago Works (T-point). Since the forced air cooling system has been verified, the 1650deg.C class next generation GTCC power plant with the forced air cooling system is now being developed. Final confirmation test of 1650deg.C class next generation GTCC system will be carried out in 2020.


Author(s):  
Hussein M. Maghrabie ◽  
A. S. A. Mohamed ◽  
M. Salem Ahmed

Abstract Utilizing photovoltaic (PV) panels for generating electrical power is accompanied with a low electrical efficiency that is further reduced as its surface temperature surpasses an acceptable limit. In order to overcome this critical issue, it is necessary to maintain the PV panels relatively at low surface temperatures as possible as using appropriate cooling systems. The current implementation assesses experimentally the performance of a combined PV thermal (PV/T) system using a forced-air cooling system during April, May, June, and July of summer weather of Egypt. The results reveal that the highest values of the solar intensity and the ambient air temperature are obtained in July. Employing the forced-air cooling system reduces the average temperature on the front and back sides of the PV panel during July by 12% and 12.8%, respectively. In addition, the forced-air cooling system enhances noticeably the electrical power output of the PV panel by 3.3%, 4.3%, 4.5%, and 6.1% during April, May, June, and July, respectively. Moreover, the maximum value of the average thermal efficiency achieved during July is 37%; whereas, the corresponding value of the average overall efficiency fulfilled during April is 48.7%.


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