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light-efficiency
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Energy efficient cultivation of microalgae using phosphorescence materials and mirrors
, Article Sustainable Cities and Society ; Volume 41 , 2018 , Pages 449-454 ; 22106707 (ISSN) ; Shafii, M. B ; Roshandel, R ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
In the present study, two novel annular photobioreactors (PBR) were developed to enhance microalgae growth. One of these photobioreactors used mirrors outside the PBR, while the other one utilized phosphorescence materials inside the PBR. The results of the study suggested that the use of mirrors and phosphorescence materials led to 70% and 30% increase, respectively, in the light intensity without any additional energy consumption. Further, the results revealed that when compared with the base case, the biomass concentration increased by 91% and 24% in PBR with mirrors and phosphorescence materials, respectively. In conclusion, an improvement in PBRs resulted in efficient light to biomass...
Electrolytic capacitor-less AC-DC LED driver with constant output current and PFC
, Article 6th Annual International Power Electronics, Drive Systems, and Technologies Conference, PEDSTC 2015, 3 February 2015 through 4 February 2015 ; 2015 , Pages 107-112 ; 9781479976539 (ISBN) ; Rezazadeh, G ; Zolghadri, M. R ; Noroozi, N ; Sharif University of Technology
Abstract
Recent developments in improving lighting efficiency and cost reduction of LED's have caused them to be a suitable alternative for the current lighting systems. In this paper a novel off-line structure is proposed to drive LED's. The proposed circuit has a high power factor and high efficiency and a long lifetime. To increase the life time of the converter, the proposed circuit doesn't use any electrolytic capacitors in the power stage. The proposed circuit consists of a transition mode (TM) Flyback converter in order to have power factor correction (PFC). A Buck converter is added to the third winding of the Flyback transformer in order to create two paths for the electrical power. DC power...
Flicker-free electrolytic capacitor-less universal input offline LED driver with PFC
, Article IEEE Transactions on Power Electronics ; Volume 31, Issue 9 , 2016 , Pages 6553-6561 ; 08858993 (ISSN) ; Rezazadeh, G ; Zolghadri, M. R ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2016
Abstract
Recent developments in improving lighting efficiency and cost reduction of LEDs have made them suitable alternatives to the current lighting systems. In this paper, a novel offline structure is proposed to drive LEDs. The proposed circuit has a high-input power factor, high efficiency, a long lifetime, and it produces no flicker. To increase the lifetime of the converter, the proposed circuit does not include any electrolytic capacitors in the power stage. The proposed circuit consists of a transition mode flyback converter in order to improve power factor. Additionally, a buck converter is added to the third winding of the flyback transformer in order to create two parallel paths for the...