Solar protection devices combined with glazing. Calculation of total solar energy transmittance and light transmittance

2006 ◽  
Keyword(s):  
Solar Energy ◽  
Light Transmittance ◽  
Protection Devices

scholarly journals Gate-controlled VO2 phase transition for high-performance smart windows

2019 ◽  
Vol 5 (3) ◽  
pp. eaav6815 ◽  
Author(s):  
Shi Chen ◽  
Zhaowu Wang ◽  
Hui Ren ◽  
Yuliang Chen ◽  
Wensheng Yan ◽  
...  
Keyword(s):  
Phase Transition ◽  
Solar Energy ◽  
Energy Saving ◽  
High Performance ◽  
Light Transmittance ◽  
Energy Regulation ◽  
Practical Application ◽  
Theoretical Limit ◽  
Smart Windows ◽  
Infrared Transmittance

Vanadium dioxide (VO2) is a promising material for developing energy-saving “smart windows,” owing to its infrared thermochromism induced by metal-insulator transition (MIT). However, its practical application is greatly limited by its relatively high critical temperature (~68°C), low luminous transmittance (<60%), and poor solar energy regulation ability (<15%). Here, we developed a reversible and nonvolatile electric field control of the MIT of a monoclinic VO2 film. With a solid electrolyte layer assisting gating treatment, we modulated the insertion/extraction of hydrogen into/from the VO2 lattice at room temperature, causing tristate phase transitions that enable control of light transmittance. The dramatic increase in visible/infrared transmittance due to the phase transition from the metallic (lightly H-doped) to the insulating (heavily H-doped) phase results in an increased solar energy regulation ability up to 26.5%, while maintaining 70.8% visible luminous transmittance. These results break all previous records and exceed the theoretical limit for traditional VO2 smart windows, making them ready for energy-saving utilization.

Rendez vous with Saturn's rings

1984 ◽  
Vol 75 ◽  
pp. 743-759 ◽  
Author(s):  
Kerry T. Nock
Keyword(s):  
Solar Energy ◽  
Electric Propulsion ◽  
Power Source ◽  
Propulsion System ◽  
Low Thrust ◽  
Ring Plane ◽  
The Earth ◽  
Total Impulse ◽  
Saturn's Rings

ABSTRACTA mission to rendezvous with the rings of Saturn is studied with regard to science rationale and instrumentation and engineering feasibility and design. Future detailedin situexploration of the rings of Saturn will require spacecraft systems with enormous propulsive capability. NASA is currently studying the critical technologies for just such a system, called Nuclear Electric Propulsion (NEP). Electric propulsion is the only technology which can effectively provide the required total impulse for this demanding mission. Furthermore, the power source must be nuclear because the solar energy reaching Saturn is only 1% of that at the Earth. An important aspect of this mission is the ability of the low thrust propulsion system to continuously boost the spacecraft above the ring plane as it spirals in toward Saturn, thus enabling scientific measurements of ring particles from only a few kilometers.

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