January 17, 2016
In the morning we need lighting shower in order to be awake from our long sleep. But the same intesity of lighting whole day long is not good for the people, because change of morning day and night , additionally different kinds of works. We measure the light quality with physical instrument but our eye is user for lighting. Our eye is not the same like measurement device. We measure same lux but we feel LED lighting is more brighter than conventional gas igntion lighting. Why?
The Lighting design must focus on User not only on measurement device. We get bad feeling ,when we see directly lighting source like sun. The Uniformity, optimal lighting energy distribution make us happy, getting good feeling. We must know more about user, that is to say , about us and our eye , relevant feeling from lighting energy and its distribution. Such these new lighting technologies will positively affect circadian rhythms, improve reading comprehension, and promote focus and concentration for user in all indoor area where we are simply installing tunable LED lighting for dimming and glarefree lighting source without any frequence change. We should avoid giving overstress to our eyes and make me and you aware of how this type of technology impacts our living and working environment. We must be sensible with new possible technology. The lighting has not same quality. They have huge different quality, up to our knowlege, technique and our will. written by Doo-Bong Chang
February 5, 2016
We use UGR according to CIE 117:1995 or lx DIN EN 12464-2 but this procedure requires symmetric light data. Sometimes we don not have one sorce but many like LED lighting. Problem is that all regulation was defined before LED period. Even with good value 12-19 UGR we can nor feel not so good , why?
The lighting technology must serve for our eyes. Our human eye can adapt through wide range of lighting level (from moonshine to sunshine) Our Iris works continuously to control the amount of light that enter in our eyes. Glare can come directly from light source or reflected from surface. If the light is not comfortable, then it stress our eyes. The correct position of light source, good reflector, or diffusor can help us. We measure the amount of light but die uniformed , wide area and smooth distribution of lighting perfomance or intensity are also important for light design and engineering.
Light pollution is the spillage of light into area where it not desired. especially floodlighting of outdoor sport facilities very bad, even though there are European standard to be holded. Nobady does not care about that. The Flickering probem is also serious for TV broadcast in sport event. Good LED driver can prevent or minimalise this flicking caused by frequency or instabile current supply.
What our eye get, is the distribution of luminace cd per m square and through our pupil surface. Our pupil size can be adapted not only for amount of lumancae but also show our emotional situation. Therefore the light source cd or lumen or reflected surface in lx are not only impact of perception but also emotion. Our emotion make our pupil wide. Our eyes are not only for seeing but crosslinked. All factors are focused on our well being of eyes and finally we can feel good. written by Dr. Doo-Bong Chang
January 30, 2016
We see some advertisements that smart LED Lighting Systems are saving customers up to 90% on lighting energy costs ! If you do not use the lighting, you can save 100 % ! We must be a little careful for such a advertising.
For example HQI, HQL, HQJ 400 W plus ca. 50 W driver power comsumption with 120 LPW it must have 48 000 lm but they have just max. 75 lm/W !
Comparing to LED lamp it has 160 W ( LPW 125 max) including all. Without using sensor we can not save 90 % percent energy. Even with sensor and dimmer ( with our usual habit of lighting, maybe it is possible for corridor area because people appear very seldom) we must be very careful!
Occupy sensor > it is up to how many time it can be activated ( 10-20 %)
Daylight sensor > it is a little easier but it is up to area and countries and set up point value ( 700-1000 lx).
These smart lighting system especially sensor and dimmer can be first washed-out ( out of order) from all components of lighting on my experience. Sensor and actuators are basic for smart lighting but they are not itself smart but our strategy !
January 22, 2016
If we see the led lighting catalogue from some manufacturers, we can see Photometry distribution. c -axis is very homegeously pictured. The Problem is diagramed for light distribution for the asymmetric wides lighting like flood lighting. c is homegen but g axis shows between 20-30 grade. If we measure the lighting with contant interval , we make mistake, because we have to linearize two measured points and power distribution is not homogeneous. We lose real intensity of the lighting. We must measure very tighty for the area of a main energy ,differnt to area of week energy. If we do not, we have wrong IES file for simulation.
June 29, 2016
This question is very provocative, at least it sounds like so. We use LED lamps or we sell lots of LED lamps. But do we understand really what is LED what kind of characteristics they have and what kinds of physical model LED has?The LED is P-N transition (Galliumarsenide or Metaloxide). If it get electric power electron and hole begin to move and conflict mutual then produce lighting ( this description is not barely correct: there are no hole and just electron moves from stable level to excited level via PN crossing and fall down again. If they are falling down in visuable energy level, we can see the light, otherwise IR or UV but during the LED manufacturing their crystal structure could be demaged, it means internal resistance ) the most of lighting in LED reflect back and not go through filter layer. max efficiency is ca. 40 % . It is also up to Color temperature , more blue more efficient, more warm color like under 3000 K it neans more waste energy, more warm causes more current and it is deadlich for LED ( max over 80 % into warm-hot waste energy), Normally we think how many input electron create photon output . This efficiency is up to the structure, material and how long being in excited condition. Too much power can shoot too higher energy band and molecule bond can be brocken or melt. Simplely we think about the Efficiency lm / W= lm/ U*I so too much current & voltage mean less efficient and make heat that destoy bond and structure. We can not reach more than max. efficient roll-off. After this roll -off , you can just destroy LED whatever you do.
LED is not same LED. How can we use these LED for best LED lamps? If we do not understand exactly LED then we can not make good LED lamps. We heard about LPW in LED or 300 LPW . How could we reach it? One example 180 Lm/w This performance will be reduced through coverage ( 5-10%) and through driver(20-30%) 108-129 lm/w is normal luminare LPW. We can reach 180 Lm/W in worst case with 300 Lm/w super chip. The question is how we can improve LPW at same time not to take a loss of life time expectation. The increase of LPW within case of not innovative technical backgroud is not always best but stabil and optimal . higher case temperature/chromaticity shift less average lumens. Normally middle chip need Vf 3,6 V If 60 mA 0,2 2 W. We reduce vf 2,9 Vf we get 0,17W 77 % improvment ! At the moment the development need other level. the first imrovement requires Materail and crytal structure (material substrate material are sapphire, one crytal Aluminiunoxide or Galliumoxide etc. structure like QLED (Quantum Dot light Emittering diode) the second improvement requrie suitable coverage and drivers.
written by Dr.Chang
When I read in the newspaper that Spain had experienced a blackout, the timing immediately caught my attention: it occurred in the middle of the day, when solar energy production is at its peak.
Having worked for many years at Siemens Kraftwerk Union, I am familiar with power plant operations and am trying to understand the relationship between the power grid and the generating plants in such situations.
When grid frequency drops too far — for instance, due to a sudden increase in power consumption or the unexpected shutdown of power plants — it can become extremely dangerous for the stability of the grid and the connected systems.
For example: at the first warning level, typically at 49 Hz, measures like load shedding are initiated.
If the frequency drops further to a critical point, automatic shutdowns of many power plants are triggered.
Nuclear power plants are particularly sensitive in this regard, as they often have very large turbines (especially in the low-pressure sections) and large blades. Frequencies below 500m Hz can cause these massive components to resonate dangerously.
In Spain, the blackout occurred around noon, precisely when photovoltaic systems were producing their maximum output.
The power fed into the grid increased sharply, but with renewable energy sources, it is much more difficult to regulate frequency precisely.
Due to the high levels of solar generation, several conventional power plants — such as coal-fired plants — had to significantly reduce their output.
However, under low-load conditions, maintaining stable frequency control becomes very challenging.
In such a state, even a minor disturbance can trigger a chain reaction across the entire grid, especially when only a few power plants are still actively participating in frequency regulation.
This can lead to a total grid collapse.
Is such a blackout only possible in Spain because of its high share of solar power?
In my opinion, a blackout could occur anywhere where too few turbine-based plants are available to support frequency regulation — and Germany is particularly at risk.
Wir benötigen Ihre Zustimmung zum Laden der Übersetzungen
Wir nutzen einen Drittanbieter-Service, um den Inhalt der Website zu übersetzen, der möglicherweise Daten über Ihre Aktivitäten sammelt. Bitte überprüfen Sie die Details in der Datenschutzerklärung und akzeptieren Sie den Dienst, um die Übersetzungen zu sehen.