Olive Drab Green
Well-Known Member
i.e. Electroluminescence vs. Fluorescence
Can a light get too efficient
- Thread starter Uncle Reefer
- Start date
Indeed.
And, of course, incandescence.
You'll be able to hold a 50w LED lamp in your bare hand when it's "on", let's see you do that with a 50w halogen as so much more of the electrical energy is turned to heat.
Olive Drab Green
Well-Known Member
This was always my point, regarding gas discharge lamps vs. COBs/LEDs generally.
Which some people do not seem to have a grasp on yet, but that will come.
wietefras
Well-Known Member
Yet the fact is that both will heat up a closed room at the same pace. Laws of thermodynamics apply here.
There can be a difference in how easy it is to extract the generated heat from the space (radiant vs convection heat), but the efficiency of the light truly has no noticeable effect on the room heating up.
Stink Bug
Well-Known Member
Your ac just does not need to run or cycle on as much with the lower btu output of the more efficient leds/lights.That would account for the rise in humidity. It has nothing to due with this ncreased plant transpiration. Evaporator cores not only collect heat from the air. They also collect moisture.
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Dear oh dear, it still hasn't sunk in yet.
If one thing converts more of that 1kw of energy into light than the other, with the other converting more energy into heat than light, how in hell's name will they heat a room up at exactly the same rate as the conversion of energy is completely different with one converting more energy into light compared to the other?
wietefras
Well-Known Member
I get that it can be difficult to comprehend concepts like this, but try at least.
What do you think happens with that light when it gets absorbed? Laws of thermodynamics baby!
All the energy you pump into that closed space ultimately gets converted to heat. Even when you add plants, since only a very small portion of the light gets converted in biomass.
I give up, you've proven you don't understand what you are talking about and have no intention of trying to do so.
Stink Bug
Well-Known Member
The law of the conservation of energy applies here.
Energy can neither be created or destroyed. It can only change forms.
Rocket Soul
Well-Known Member
So i might be wrong...
But the the temps being lower, and cold air dissolves less water than hot air: the amount of water being transpired by the plants being the same, just for examples sake, wouldnt there be a lower RH when the air is warmer? For example, 5 liters of water disolved in 15C would give a higher RH than the same 5 liters disolved in 25C as it Relative Humidity. This how i thought dew point, foggy windows in the winter etc worked.
I know in a grow room its a bit different cause the plants will transpire differntly with different RH/Temp/VPD: changing these factors would prob mean that those 5 liters of the example wont be the same.
Stink Bug
Well-Known Member
That's a good point. And would depend on ambient temperature in the tent from one light type or source to another.
SSGrower
Well-Known Member
The universe is cooling down, we cant get away from it. Some the the energy for lights is heat, some is light, the light eventually gets changed to heat either in photosynthesis or by impacting an opaque objrct and transferring the energy it (the photon) contains into heat. This is where insulation comes into play. The solid mass heatsnup and radiates heat back, there are "losses", this takes time.
I'll put it simply.
My homemade led panel pulls 135w from the wall, and I can hold my hand against the metal plate which acts as a heatsink all day if I wanted to, same as I could hold the the led side all day, same as I could hold the driver all day.
If it was a little bigger, say 165w, the temperature difference would be insignificant.
Do you think I could do the same with a 150w HID light?
I have to run a small fan heater to keep temperatures vaguely constant, would that come on more or less often with a 150w HID light comared to the LED equivalent?
Ambient plays a part in heat dissipation, but only when what is being dissipated is not driving the ambient upwards due to it being in an enclosed space.
You get the foggy windows because of a sharply lower temperature on the window, which means the air condenses which increases the density of the air. That means more water vapour, which then collects on the colder surfacedue to the rh being higher as more air occupies the same volume.
Or, more simply, does it rain on colder days when clouds form and the rh is higher, or on hot, sunny, days when the air is drier thanks to a much lower rh?
The rest of the heat is on the heatsink on the back of the light whick is still in the room... And a 1k will heat the room up the same as a heater of the same wattage if the room is sealed
Hold a 50w cob with no heatsink...good luck with that.
And a huge factor is what is driving the ambient, and is why I used my panel as a perfect example of the difference in how led and HID work, one produces much more heat than the other, unless you are saying I could hold my hand against a 150w HID lamp all day without discomfort.
Your going to feel pretty stupid when you finally figure out your wrong. But don't feel bad I used to think the same thing until I did some research/ real world testing