What would you recommend to replace a 1000w HPS in a 4x4 tent?
- Thread starter Dr.Pepper99
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wietefras
Well-Known Member
In the case of three closed and (sort of) insulated rooms, they would all heat up at more or less the same rate and certainly to the same stabilized temperature.
WeedSexWeightsShakes
Well-Known Member
So really the biggest benefit is just that fact the LEDs are more efficient and you don’t have to use as many watts, therefore not as much heat is created.
1000w hps ~ 600-750w led
Yeah?
1000w hps ~ 600-750w led
Yeah?
JSheeze
Well-Known Member
Yes. And even at the same wattage it will be cooler but the biggest deal is the less $$ for electric and less heat.
LEDs have cooler temps comparatively watt for watt (because of heat sinks and efficiency), but are even cooler if comparing lights of equal PPFD considering the LED will use less watts than the HPS to achieve the same PPFD (like what you were getting at).
Cheaper on the monthly bill and cooler in the tent. Also can run LEDs at slightly higher air temp because a greater % of the EM spec is absorbed for photosynthesis compared to HPS that puts off more un-used specstrums that get coverted to heat at the leaf surface. This happens more with HPS than LED (spectrum) so you have to keep air temp cooler with HPS and air temp hotter with LED. This means less venting with LED ontop of it producing less heat.
Check this article out...
https://www.maximumyield.com/the-relationship-between-leaf-surface-temperature-and-lighting-spectrum/2/3226
WeedSexWeightsShakes
Well-Known Member
Man I still find it hard to believe that they would heat up at the same rate. Isn’t it like saying a 1000w heater would heat at the same rate as a 1000w of led?
WeedSexWeightsShakes
Well-Known Member
Yeah the QBs in my setup work great in the low 80s with rh in the 60s. I even have let them get into the 90s and plants looked amazing, as long as I kept them well watered lol.
hybridway2
Amare Shill
U guys dont know. Ask Yoda. Dont make me @ him, just admit it wrong.
A 600w hps barebulb in a zipped tent with the ballast outside the tent should about equal the LEDs & driver in the tent also using 600w.
Yes a 600 hps barebulb makes a room as hot as 600w led with drivers. Good thing about HPS is the ir in the 800+ range is increasing leaf temp by about 7°.whereas our led 730nm is just for color/spectrum.
Ambient they equal out.
And if you dont think say x4 drivers to bang a 1000w led doesnt put out allot of heat (like 40%) you're trippin.
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Yodaweed
Well-Known Member
The advantage to LEDs is they make more usable light than other lighting sources so you can use less watts to get the same job done.
Like 750-850watts of top quality LEDs will be equivalent to a 1000w SE HPS so you can save on electric and that makes less heat and then you save on less air conditioning.
Watts are what make heat the lighting type does not matter. That's why you can easily calculate heatloads via watt output https://www.traditionaloven.com/tutorials/power/convert-watts-w-to-btu-per-hour.html
Example:
power from watt to BTU per hour Conversion Results:
Amount : 1000 watts (W of power)
Equals : 3412.14 BTU's per hour (Btu/h / power)
Whether or not that is a good investment is up to the buyer to decide.
JSheeze
Well-Known Member
BTU is a quantity of energy, not the type of energy exhibited.
You are correct that 1 watt = 3.4 BTU but they are just units of energy. What you decide to do with that energy effects air temp.
I explained that you can use 1000w to recharge a battery or 1000w to power a space heater. Both are consuming watts or BTUs or whatever measurement of power you'd like to use but what we decided to do with those quantities of energy effected our final air temperature differently.
A device that has more of its total operating watts being coverted into BTUs of heat initially (if you prefer using BTUs), is going to be hotter vs a device that doesn't. Is going to convert more heat than a device that doesn't. Is going to heat up the air quicker than a device that doesn't. Ect ect...
Like @hybridway2 is describing its not the light energy increasing air temps its the tech inside the tent, drivers inside the tent (if you decide to mount them inside). Take away the drivers but leave the 2 types of light inside and we see the HPS is going to be hotter than the LED. Its not the PAR radiation needing heat management, its the operating temps of the tech inside the tent.
- Focker out
time to smoke some popcorn lolbut it still smokes..
Midnight Warrior
Well-Known Member
QBs are cheap as chips now require no soldering or any electronics experience.
hybridway2
Amare Shill
NanoGadget
Well-Known Member
600 with bleeding edge led tech is actually pretty close to a 1000 watt SE HPS in terms of light output.
NanoGadget
Well-Known Member
Also, can everyone turn the sarcasm down a couple notches? I can't even tell which side of this played out argument people are even on anymore. For fucks sake.
Rahz
Well-Known Member
That's true for retail, but it's possible to DIY a 500w output lamp to match a 1000w SE. I think there are some retail lamps out there with near DIY performance but they're expensive.
NanoGadget
Well-Known Member
I know the hlg 600w diy kit was pretty close, and i know people have gotten some sick ppfd with strips, but as a general rule the 600 to 750 range will replace a 1000w SE. I'm trying not to be too nitpicky because i don't want the anti LED contingency to have an aneurysm.
Prawn Connery
Well-Known Member
Can you ask your engineering friends why, in this actual demonstration, both tents warmed up by the same relative amount?
The amount of energy needed to raise temperature has a formula:
Energy = Specific Heat x Mass x Temperature Difference
Both tents had the same specific heat (air) and mass (cubic capacity), and the recorded temperature differences were:
LED 400W = 7C
HPS 600W = 10C
A 50% increase in energy equated to a 50% increase in temperature.
How do you explain that?
Also, you haven't explained to us where all those photons go if they are not converted to heat. We know tents are not a closed system, but we can make them - to all intents - light proof. So what happens to all the photons?
A lot of what you're saying doesn't actually make sense. For example, "rates matter" - yes they do. But once the tent reaches equilibrium - as in the above demonstration - the rate of heat (energy) going into the tent vs the rate of heat (energy) leaving the tent (through the walls and air transfer) stabilises.
This is exactly what you see in the video: the HPS heats up the tent quicker (faster flow of energy), but once both tents reach equilibrium, their temperatures stabilise.
We would all agree with you if you were correct, but I think you'll find it very hard to find someone here who agrees with you based on the simple notion that the science is against you.
JSheeze
Well-Known Member
First off this really is extrapolating because I don't know all the variables and typically you'd try to control for one variable at a time.
One could say that the PPFD is the same between both lights and so it just requires 170 more watts to create that PPFD for the HPS compared to the LED and that this extra 170 watts is released as heat immediately, buuuut I won't cop out, ill go down the rabbit hole all the way with ya.
First off, I'm not sure if these were done side by side, at the same time, or at different times. If they were at the same time they will be interacting with each other throwing results off. We'd not know how much of the heat was flowing to the room by each tent respectively. This effects inside tent temps because a lower overall outside means inside heat flows out easier, or inside temps would be cooler. If outside air is heated by both sources we'd not know who to blame. I'd also like to know the temps outside the room as well as inside the room and inside the tent. These temps all matter as heat flows to colder environments.
Secondly, are the ballast and/or drivers mounted inside or out?
I assumed a few things.
1. They were conducted at different times. (Extrapolting back the clock vs temp on the vid it looks like the HPS started out in a colder room than the LED, this starting temp difference between the lights can be a possibility of a few things, being in different rooms, or conducted at different times, or convection currents and temp gradients in diff areas of the room but being conducted at the same time in the same room. I chose same room, same area of room, but at different times, too minimize variables, although I have no clue)
2. The outside temp of the room was the same in both runs.
Ok now my process...
The vid shows 2 temp gauges with running clocks but they aren't at the same speed. Also the video doesn't start the LED clock till 4ish min (so fast hard to tell) but you can't read the data till later anyways due to a black LCD screen. Because of this I started plotting my data points at 10min. I then took readings at 30min and 60min. This resulted in recording one 20min section (30min minus 10min), and one 30min section (60min minus 30min), and one 50min section (60min minus 10min).
Results:
LED inside tent temp rose 1.5° in the first 20min
HPS inside tent temp rose 6.9° in the first 20min
HPS increased inside tent temperatures 460% more than LED in the first 20min.
LED outside temp rose 0.1° in the first 20min.
HPS outside temp rose 0.8° in the first 20min.
HPS increased outside temps 800% more than LED in the first 20min.
LED inside tent temp rose 5.1° in 50min.
HPS inside tent temp rose 9.0° in 50min.
HPS increased inside tent temps 176% more than LED in 50min.
LED outside temp rose 0.2° in 50min.
HPS outside temp rose 1.2° in 50min.
HPS increased outside temp 600% more than LED in 50min.
Data & Analysis:
LED - HPS 10min...
LED - HPS 30min...
LED - HPS 60min...
Data points, delta's, plotted...
If you look at the graph you can see how the outside temps change rate at a more uniform rate. This is where I extrapolated the starting temps to be different. Each square of graph paper along the x-axis is 2.5min so 4squares left of the XY intersection is where you'd see the starting temps.
Lets assume the starting temps of 26.5° for the LED and lets say 26.0° for the HPS.
This results in a 6.0° delta T over 60min for the LED. And a 11.3° delta T over 60min for the HPS.
Not using trajectory to extrapolate starting temps and only using given data, then the LED is shown having a 5.1° delta T over 50min compared to a 9.0° delta T over 50min for the HPS.
Conclusion
We notice the different rates these lights heat up the inside tent and outside room.
We notice the HPS reaching an event horizon of internal temp as time progresses. We notice it builds up the internal temp quickly all the while increasing the outside temp more than the LED.
We notice the LED gradually and uniformly increasing inside tent temps and uniformly increasing outside temps but much less compared to the HPS. Also at much different rates. The final temps were less as well.
At the end of an hour both inside tent temps have increased but they have not reached the same temp. Both outside temps have increased but they have not reached the same temp. The HPS has reached its event horizon and increases outside temp faster (which will slow heat transfer over time from tent to room because the gradient will be less) while the LED has not reached an event horizon in temp inc and the resulting room temps rates are completely uniform and less.
Even when factoring the increase in wattage the HPS had over that of the LED, the rates and/or data still aren't satisfied by everyone's 1000w = 1000w when it comes to heat. ALL HPS DATA ARE INCREASED BY MORE THAN 148% or 1.48 (640w/430w).
60min delta I LED = 6.0°
60min delta I HPS = 11.3°
60min delta O LED = 0.2°
60min delta O HPS = 1.6°
50min delta I LED = 5.1°
50min delta I HPS = 9.0°
50min delta O LED = 0.2°
50min delta O HPS = 1.2°
If you convect your heat away, your going to have to start worrying about room temps much quicker with HPS than LED. These were enclosed tents. If convected the outside room is going to keep up with the heat production much easier with the LED than the HPS. Rates matter. Not closed systems. Even if they eventually level out their inside temps to be relatively close (we didn't convect heat away) the outside temp will be hotter with the HPS than LED, and it will get hotter quicker. And then it will need ducting. See how the rate at which something is heated matters? If they were closed systems itd be different but the fact that it's open means that the grow room walls and/or tent walls transmit heat at a certain rate inherently and thus the rate the you supply it with heat matters when looking at the temp inc over time.
The same reason we use big propane heaters to heat our houses instead of little heaters. If we used 100w little heaters for 10hrs the house would expel the heat as fast as it was being produced and you wouldn't really notice a temp change. If we used 1000w heater for an hr the same amount of work is done but at a different rate and thus the temp difference is noticed. You're right in saying that lights are pretty much crappy inefficient space heaters, the difference is, is that LEDs are crappier space heaters than HPS because they convert less of their initial energy into heat.
If the rooms were absolute barriers then yes I would say that over time 1000w LED will produce just as much heat as 1000w HPS, but as we clearly see these are not closed systems and HPS will heat up a room faster than LED.
A better expirement would have been equal wattage HPS vs equal wattage LED. Then plot internal tent temp and room temp increase over time. Also stating some initial conditions would have been nice. Ie how the experiment was set up.
Now there's a novel... Lol time to kill some brain cells haha
Liberty haze highly recommend...
Oh and where do all the photons go? They get absorbed by anything that won't reflect them. Light reaches equilibrium fast, at the speed of light, it disperses its energy over a large area, it fills the room fast, and don't forget the inverse square law of light, the density decreases with distance. At the rate light is transformed into thermal over the vast area it absorbs into and at the density its finally realized at having when it gets to the wall or wherever its finally absorbed the possible temp increase is negligible compared to the operating temps of the lightbulbs and tech inside.
*I went to school for a B.S. in engineering and a minor in math. I did not consult any peers this time.
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JSheeze
Well-Known Member
Air is not dense. There are not many particles in 1ft3 gas of air compared to that of a solid wall. Because light passes through air, the air is only minimally heated by the light. The air however is in direct contact with a thermal producing component of the light, no matter the type. How much heat transfer of that thermal producing part of the light to the air around it depends on how much energy the thermal producing part of the light is utilizing as well as the temp difference between the two mediums (air and thermal producing part of light).
Because of the inverse square law of density for light and because whatever absorbed it was not air, the majority of heat noticed from the PAR is conducted through the body that absorbed it first (most efficient form of heat transfer), then if it is enough of a temp gradient it will convect it to a colder area. Could be inside or outside the room. And because so little light hits the absoring material, compared to the amount of molecules in the absorbing material, and because the majority of it is conducted and instantaneously distributed given the speed of light, the overall temp flux is tiny.
Now the density of air on the other hand is quite less than that of a solid. That means more volume of air needs to touch a hot object to transfer heat away than the volume of a solid object that has the same thermal conductivity. So because there's not much air molecules in the room compared to the amount of PAR absorbing molecules in the room the effect of heat transfer to the air is going to have a more profound effect than to the walls. There might only be 1.5lbs of air in the room. That amount of air to cool the 500w of thermal producing part of a light vs the 500W that's absorbed by the 1,000s of lbs of grow room material.
Essentially whatever you're growing in is a giant heatsink. The air temps are effected by the light bulbs and tech CONVECTING heat, not the PAR being absorbed and conducted by the walls ect. Heat flows from hot to cold. It would not want to flow back into a hotter environment.
This is simplified. Many more variables but this is basic.
Its too late to add this data to the previous post so ill put it here...
Because of the inverse square law of density for light and because whatever absorbed it was not air, the majority of heat noticed from the PAR is conducted through the body that absorbed it first (most efficient form of heat transfer), then if it is enough of a temp gradient it will convect it to a colder area. Could be inside or outside the room. And because so little light hits the absoring material, compared to the amount of molecules in the absorbing material, and because the majority of it is conducted and instantaneously distributed given the speed of light, the overall temp flux is tiny.
Now the density of air on the other hand is quite less than that of a solid. That means more volume of air needs to touch a hot object to transfer heat away than the volume of a solid object that has the same thermal conductivity. So because there's not much air molecules in the room compared to the amount of PAR absorbing molecules in the room the effect of heat transfer to the air is going to have a more profound effect than to the walls. There might only be 1.5lbs of air in the room. That amount of air to cool the 500w of thermal producing part of a light vs the 500W that's absorbed by the 1,000s of lbs of grow room material.
Essentially whatever you're growing in is a giant heatsink. The air temps are effected by the light bulbs and tech CONVECTING heat, not the PAR being absorbed and conducted by the walls ect. Heat flows from hot to cold. It would not want to flow back into a hotter environment.
This is simplified. Many more variables but this is basic.
Its too late to add this data to the previous post so ill put it here...
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wietefras
Well-Known Member
Yes it would and it is (if correctly measured).
The difference would be that a space heater will heat the air while the lights would partially first need to heat up the walls till they start heating up the air (leds more so than HPS). So the heat up rate might be somewhat different, but in the end you will end up on the same temperature (if insulated enough)
On the other hand, the comparison is pointless for practical reasons.
1) led is much more efficient so you would need much less watts. That's where the real difference is.
2) HPS radiates more heat towards the plants (or thermometer) so in direct light things will heat up faster. Leds produce almost solely convection heat and that rises up and gets sucked out by the exhaust fan. So in a normal grow tent/room it will me much easier to evict the led heat out even at equal wattage.
In fact I have more problems getting the room up to the correct temperature with leds because of those two reasons. I have the exhaust fan on the bottom of the room to make sure the heat at least gets pulled through the plants. Plus fans up top to circulate the warm air there and even blow it down towards the plants if need be.