Are Metal Halides history?

[Paul B]

Yeah, but this is one of those things that can't be argued,

Bean old buddy, I am not argueing, I am testing. As I said, I do my own research.

You can't cheat the physics and a very poorly conducted experiment with very poor controls only serves to mislead and confuse people.

I like confusing people, it's what I do.

Without some serious thought as to how to seal the box and ensure that the air in the box is at equillibrium, the experiment is going to be misleading.

I always think seriously, I am an inventer, mechanic and electrician remember.

as if it were not true none of the science around us would work.

We all know how much the "science" of marine aquariums works.

And I actually did go to school and learned exactly this principal of watts vs heat. But to me, it is still an interesting experiment, and I just love to experiment. I have enough lights, motors and styrofoam boxes around my workshop to built a space shuttle, with an HD TV in the den.

When I get one of my amp meters working, I will let you know how it turns out.

I just love this stuff. Something to experiment on, my fish will thank you that I took the burden off them for a while.

[BeanAnimal]

Experiment away Paul... If you do find the first law of thermodynamics to be in error please don't rub it in, as I have a feeling that many dead physicists would role in their graves

FWIW: the "experiments" we are talking about conducting here are the same basic experiments used to prove the theory (now known to be a law of physics).

Joule (if I remember) used an insulated tank of water (as I have proposed above) and found that no matter what "work" was done inside of the container (electrical, mechanical, or chemical) that the temperature rise was 100% predictable given the same amount of work. He did so through various experiments that that imparted work into the insulated tank of water. I think in one experiment he used a weight to spin a paddle in the tank. He found that knowing the mass of the weight and the height it dropped, he could quantify the energy lost by the weight and gained in the tank, of course as HEAT. From there he went on to prove that no matter what type of energy conversion (mechanical, electrical or chemical) that the result was the same. That is, the temperature gain in the tank was exactly = to the energy put into (work done) in the tank.

I would also point out (and should have above) that somebody (bonsai maybe?) pointed out that it is not "the law of conservation of heat": Well it i snot worded that way but Clausius (sp?), Rankine and Joule, set out to prove that heat and energy were the same thing, and that it why the "law of conservation of energy" IS the First Law of Thermodynamics, not the "Fist Law of Energy"

Then again the SI unit of energy is named after the guy

NOTE: We talk about Ohm's law here in the DIY forum a lot, but I would imagine that most folks have no clue that it too is governed (and in fact provable) by the above, as is Joule's law



In all honesty, I think you will have some fun with this. Knowing what the results should be will end up driving you to keep fixing the experiments flaws until you get the results that match the physics. As long as the results don't match, then you will need to look for the "leaks" that are allowing energy to escape!

[SteveValle]

This has been a very enlightening thread, no pun intended.

[PowermanKW]

Originally Posted by BonsaiNut

I think we are saying the same thing in different ways. However I prefer to think of energy in other forms than heat When you say it "all becomes heat in the end" you are using heat as a baseline. Since energy can be a lots of different forms, heat is no better or worse than any other form I could just as easily say "it all becomes kinetic energy in the end" and you could not argue against it. It is ENERGY that is the baseline... not heat

But I enjoyed this conversation And if, within my frame of reference, a metal halide light makes my aquarium water warmer than a LED fixture that uses the same amount of electricity... (Oh no make it stop)

Wiki

Temperature: Therefore, temperature is tied directly to the mean kinetic energy of particles moving relative to the center of mass coordinates for that object.

Heat:A related term is thermal energy, loosely defined as the energy of a body that increases with its temperature. Thermal energy is also sometimes referred to as heat, although the definition of heat requires it to be in transfer between two systems.


Don't call it heat if it sounds better to you... but everything ends up as thermal energy... and in a measured system...an aquarium with a energy conversion device such as a light with set boundaries... an insulated box or the walls of the room.... 100 watts of light is 100.00 watts of thermal energy added to that system... and that system will have 100.00 watts of energy that can easily be measured.... of course we are not mentioning any that escapes the boundaries.

Light is electromagnetic energy, that when it encounters matter, it transfers energy into kinetic energy. Heat is the measure of the average molecular kinetic energy of a substance... temperature. Your 60 watts of electromagnetic energy that the light fixture that is 60% efficient just produced... just got converted into 60 watts of thermal energy... the other 40 watts powering the 100 watt fixture were directly converted into thermal energy... for the grand total of 100.00 watts of thermal energy.... in this case added to your aquarium, or the surrounding room until all bodies in the system have achieved equilibrium

[larsonjera49]

Great info guys! I'm actually thinking about replacing my metal halide system with either LEDs or T5s. My buddy whose a San Jose electrician is helping me, so we've been discussing this exact topic. He was saying the LED is a ways from being as efficient as the T5s (i.e. T5s around 105 lumens/watt and LEDs 70 lumens/ watt at best) Also, LEDs have somewhere around 30% more heat dissipation, which increases energy costs to cool the tank. Anyone have more opinions on which one to go with?

[ksc]

With some of these new digital ballasts coming out, I doubt MH is going anywhere soon. These numbers are pretty good if true:http://www.accendoelectronics.com/Gl...Products.shtml

•Direct Digital Ignition (DDI) micro-processor control algorithms optimize the balance of current with lamp gases.
•Micro-processor based system performs at 97% efficiency delivering the highest lumen output per Watt in the market today (116lm/W+).
•Industry leading technology produces more penetrating and longer lasting light than core and coil (magnetic) ballasts for significantly less energy consumed.
•The high efficiency of the DHID ballast allows Watts input to be most efficiently converted to Watts output as lumens with only 3% losses to heat.
•System efficiency virtually eliminates electrical losses and corresponding ambient heat. The GloGreen DHID ballast power factor is >98%.
•DDI minimizes lamp wear, and in turn prolongs the life of the lamp by 100%, dynamically maintaining lumen output of aging lamps with automatic loss of lumen compensation.
•HID lamps operated with the GloGreen ballast will not degrade more than 5% over their entire lifetime; i.e. 95% lumen maintenance - no relamping is required, bulb is only changed at its life end of 40,000 hours and beyond (especially when instant dimming is utilized).
•Instant dimming and full power resumption is managed by the DDI micro-processor via Accendo Motion Sensor (discrete or RJ-11) or PLC (Analog 0-10VDC) input, or pre-programmed Automatic Dimming input. For Automatic Dimming, a Pre-Programmed Device (PPD) is required; the small module plugs into the RJ-11 port on the DHID ballast; the PPD contains the dim schedule program which is preset to the customer application specification.

[Paul B]

Experiment away Paul... If you do find the first law of thermodynamics to be in error please don't rub it in, as I have a feeling that many dead physicists would role in their graves

I have one thing none of those dead physists have, a styrofoam box. OK two things, I doubt many of them has an AC motor.
(I also don't know why we are talking about ohm's law either, but I had to take 4 years of it to become an electrician. Total waste of time for an electrician)

Anyway, the problem with these discussions on a fish forum is that physics don't really apply here. OK I know I will have to explain that so Bean does not get a stroke.
Take Neuton for instance. If you take two different weights and climb to the top of the Leaning Tower of Piza and drop them they will hit the ground at the same time. He was wrong and they will not. Maybe on an asteroid that has gravity but no atmosphere that would work but not on earth and being that we live on earth, that theory is not accurate here. Thats why they always end that theory by saying "in a vacuum". We don't have any vacuums here on earth, OK maybe some Electroluxe's, but thats it. (try it with a feather, on earth)

Einstein was another one. Great theory and when my reef tank goes almost as fast as the speed of light, my moorish Idol will not age and he will live forever. But not here on earth and not today because we can't yet go the sped of light and acording to him, we never will. We will probably also never know. It really confuses me when I think of that space ship going the speed of light and wondering why the headlights don't go faster than the speed of light.

As for MH lights heating the water as much or more than LEDs, there are too many variables to test that with physics but I can test it in practice. I can take a 100 watt MH light and put it 6" off some water then do it with LEDs.
One problem is that with MH lights, much of the heat is generated by the ballast so if the ballast is remote, that heat will not be transfered into the water. Then we have the problem of the shape of the lamp. With a MH the lamp is round allowing most of the light to be shed to the back and sides so the quality of the reflector is a factor. LEDs for fish tanks use no ballast but they have reflectors that direct the light downwards.
Both lighting systems put out different wavelengths of light which is also a factor.
I do know, practically speaking that I did have MH for many years and my tank ran about 6 degrees hotter. Now my new LEDs use about a third the amount of power and emit about 25% more light (yes I know this is totally against the laws of physics, but the physicists did not have LEDs or reef tanks) So for me, and I mean no disrespect to the dead physicists LEDs use less power, supply more light and heat the tank much less. This I can show you and prove by letting you put your hand in the water. You can see it with your eyes and feel it with your hands. Of course you can dis prove this with math and OHMs law but my fish do not know OHMs law, they just want to be comfortable.

[BeanAnimal]

Originally Posted by Paul B

(I also don't know why we are talking about ohm's law either, but I had to take 4 years of it to become an electrician. Total waste of time for an electrician)

Ohm's law is, well law because it only works if the First Law works

Yes I agree that most electricians have no use for Ohm's law... but then again you know what I think of most electricians.

Anyway, the problem with these discussions on a fish forum is that physics don't really apply here. OK I know I will have to explain that so Bean does not get a stroke.
Take Neuton for instance. If you take two different weights and climb to the top of the Leaning Tower of Piza and drop them they will hit the ground at the same time. He was wrong and they will not. Maybe on an asteroid that has gravity but no atmosphere that would work but not on earth and being that we live on earth, that theory is not accurate here. Thats why they always end that theory by saying "in a vacuum". We don't have any vacuums here on earth, OK maybe some Electroluxe's, but thats it. (try it with a feather, on earth)

The nice thing about the "First Law" is that there is no wiggle room, the ENERGY has to go somewhere and for better or worse, that somewhere ends up being HEAT

As for dropping pizza from the leaning tower of Pisa... yeah that damn pesky air tends to be able to rub on falling objects and slow them. Guess where their potential energy goes instead of acceleration? Of course HEAT due to friction

Einstein was another one. Great theory and when my reef tank goes almost as fast as the speed of light, my moorish Idol will not age and he will live forever. But not here on earth and not today because we can't yet go the sped of light and acording to him, we never will. We will probably also never know. It really confuses me when I think of that space ship going the speed of light and wondering why the headlights don't go faster than the speed of light.

I have spent most of my adult life reading Einstein's works and trying to understand them. Sadly, I am not much further along than you

As for MH lights heating the water as much or more than LEDs, there are too many variables to test that with physics but I can test it in practice. I can take a 100 watt MH light and put it 6" off some water then do it with LEDs.

The MH will certainly heat the water more. Much of its radiated energy is at a wavelength easily absorbed (converted) by the contents of the tank.

One problem is that with MH lights, much of the heat is generated by the ballast so if the ballast is remote, that heat will not be transfered into the water.

I do know, practically speaking that I did have MH for many years and my tank ran about 6 degrees hotter. Now my new LEDs use about a third the amount of power and emit about 25% more light (yes I know this is totally against the laws of physics, but the physicists did not have LEDs or reef tanks)

None of your observations contradict the laws of physics. The two different lamps are imparting different amounts of energy into the "tank". However both are imparting 100% of their energy into the room

To use the "tank" as the frame of reference to quantify energy, the tank would need to be blacked out and the lamps and ballasts submerged in it

So for me, and I mean no disrespect to the dead physicists LEDs use less power, supply more light and heat the tank much less.

Yes. Watt for Watt LEDs radiate less heat INTO the FISH TANK

[110galreef]

Originally Posted by ksc

With some of these new digital ballasts coming out, I doubt MH is going anywhere soon. These numbers are pretty good if true:http://www.accendoelectronics.com/Gl...Products.shtml

•Direct Digital Ignition (DDI) micro-processor control algorithms optimize the balance of current with lamp gases.
•Micro-processor based system performs at 97% efficiency delivering the highest lumen output per Watt in the market today (116lm/W+).
•Industry leading technology produces more penetrating and longer lasting light than core and coil (magnetic) ballasts for significantly less energy consumed.
•The high efficiency of the DHID ballast allows Watts input to be most efficiently converted to Watts output as lumens with only 3% losses to heat.
•System efficiency virtually eliminates electrical losses and corresponding ambient heat. The GloGreen DHID ballast power factor is >98%.
•DDI minimizes lamp wear, and in turn prolongs the life of the lamp by 100%, dynamically maintaining lumen output of aging lamps with automatic loss of lumen compensation.
•HID lamps operated with the GloGreen ballast will not degrade more than 5% over their entire lifetime; i.e. 95% lumen maintenance - no relamping is required, bulb is only changed at its life end of 40,000 hours and beyond (especially when instant dimming is utilized).
•Instant dimming and full power resumption is managed by the DDI micro-processor via Accendo Motion Sensor (discrete or RJ-11) or PLC (Analog 0-10VDC) input, or pre-programmed Automatic Dimming input. For Automatic Dimming, a Pre-Programmed Device (PPD) is required; the small module plugs into the RJ-11 port on the DHID ballast; the PPD contains the dim schedule program which is preset to the customer application specification.

These look very interesting! Especially the 0-10v dimmining ability, Work hand in hand with the APEX!!

Here is what I don't get as far as energy savings. The 250w ballast has an input of 260w and output of 250w. But they have better light output? More par...so in essence those of us w/ 250w MH's now could run say the 150w Ballast & bulb and get the same or more light output.

Would love to see how this would work on our SW needs for PAR & Corals. Also wonder how the diming would effect the MH bulb. Would be nice to be able to do dusk to dawn, w/ just MH's and not need VHO's or T-5's. That would also save money on a light build.

Given my tank, 66 x 36 x 24....
Digital MH--3 150w ballast & MH bulbs, (~450w)
Current Tech--3 250w & 2 140W VHO's over my setup ~1030w
or 144 3wcree LED's (432w) Plus i dont need 12 MW drivers, heatsink, and lots of soldering! haha

The Digital MH would basically cost the same on electricity to light my tank as would LED's month to month.





Found this interesting onn the site:

DHID Vs. LED; Myths and Facts:

When considering your lighting application solution, it is prudent to educate yourself on the available lighting types on the market today. Given the recent surge of promotion and the popularity of LED lighting, many consumers assume LED to be the solve-all for every lighting application. Although LED technology meets and exceeds the standards for many applications, one should be careful when considering LED for applications where light projection or penetration is important; i.e. applications where the light source is mounted at long distances from the target, as in Street Lighting, High-bay Warehouse, Sports Arena, Airport and Greenhouse lighting for example.


Facts about LED's


•LED's present many advantages over traditional light sources including lower energy consumption, longer lifetime, improved robustness, smaller size and faster switching. However, they are relatively expensive and require more precise current and heat management than traditional light sources.
•It should be noted that high-power (=1W) LED's are necessary for practical general lighting applications. Typical operating currents for these devices begin at 350 mA.
•One of the highest efficiency ratings of high-power white LED's is claimed by Philips Lumileds Lighting Co., with a luminous efficacy of 115 lm/W (350 mA). Please note that these efficiencies are for the LED chip only, held at low temperature in a lab. In a lighting application, operating at higher temperature and with drive circuit losses, efficiencies are much lower.
•Independent testing of commercial LED lamps designed to replace incandescent or CFL lamps showed that average efficacy was about 31 lm/W in 2008 and tested performance ranged from 4 lm/W to 62 lm/W) compared with 100-116 lm/W of DHID lighting systems.
•Solid state devices such as LED's are subject to very limited wear and tear if operated at low currents and at low temperatures. Many of the LED's produced in the 1970s and 1980s are still in service today. Typical lifetimes quoted are 25,000 to 100,000 hours but heat and current settings can extend or shorten this time significantly.

As a leader and one source supplier of advanced lighting systems for commercial and industrial lighting applications, including DHID and specific LED lighting products, Accendo Electronics has studied and field tested both LED and the next generation Digital Ballast powered HID (called Digital HID or DHID) technologies for applications requiring long light penetration and retained light quality over extended time periods. In our research, we uncovered key myths and facts about LED's you should consider when deciding on your project lighting.


Myth: LED Lighting Life Expectancy is 100,000 Hours Plus


•False! Manufacturers claim mean time before failure (MTBF) ratings on LED's to be 50,000 hours to 100,000 hours or more. Although in cases LED's do meet these extended MTBF specifications, this number must be directly correlated to the LED application itself. Factors such as mounting distance, the lumens per Watt (lm/W) rating, and operating temperature all contribute to the reduction of the LED's MTBF. Realistically, LED's used for street lighting, or high-bay warehouse applications for example, may be considered to be failed at 30,000 hours or sooner due to the significant light diminishment incurred in the time stages of the LED's operation.
•The most common symptom of LED (and diode laser) failure is the gradual lowering of light output and loss of efficiency. Sudden failures, although rare, can occur as well. Early red LED's were notable for their short lifetime. With the development of high power LED's, the devices are subjected to higher junction temperatures and higher current densities than traditional devices. This causes stress on the material and may cause early light output degradation. To quantitatively classify lifetime in a standardized manner it has been suggested to use the terms L75 and L50 which is the time it will take a given LED to reach 75% and 50% light output respectively. L50 is equivalent to the half-life of the LED.


Facts:


•The LED light quality diminishes or dims over the operating lifetime of the LED bulb. This degradation in light should be considered when reviewing the MTBF of LED's since the light emitted at the LED's life start is not equal to the light emitted at the bulbs half-life or life-end. If the LED bulb cannot produce the light output originally specified, it is a form of failure.
•Over time, heat created by LED's also has an adverse effect on the systems light quality and MTBF. Depending on the class of the LED bulb used, factors such as powder coating (filter) degradation and the material used to manufacture the LED lens, further add to the truism that LED's do not necessarily meet their manufacturer's specified MTBF ratings and lighting quality claims.
•DHID equals or outperforms the longevity of LED in most industrial and commercial applications at lower costs. The integrated microprocessor of the DHID doubles the life expectancy of the HID lamp by maintaining full level of illumination up to 28,000 – 40,000 hours and beyond when smart dimming is utilized.
•Studies have proven that DHID used as a direct replacement and mounted at the same distance as the original HID lighting, outperforms LED in many quantifiable measurements of energy efficiency and light penetration. DHID offers a market leading lumens per Watt rating of 116lm/W+ (which is 25% – 30% above LED's lm/W rating) and therefore delivers higher energy efficiency, greater light penetration, and quality light over the entire 40,000+ hours MTBF; and all for a fraction of the cost of LED.

.


LET THE ARGUMENTS ROLL!!
One way or another these new thigs all look promising for cost savings!

[BeanAnimal]

Originally Posted by 110galreef

Here is what I don't get as far as energy savings. The 250w ballast has an input of 260w and output of 250w. But they have better light output? More par...so in essence those of us w/ 250w MH's now could run say the 150w Ballast & bulb and get the same or more light output.

I think you got confused somewhere along the way...

It appears (I just browsed) that they are simply claiming that their ballast is a FEW percent more efficient than a standard mag or electronic ballast. Their claim appears to be twofold.

1. less energy converted to HEAT at the ballast = more of the energy to the bulb
2. Better arc management at the bulb = more desireable light from the bulb by keeping the plasma at an ideal state, not wandering back and forth between inefficient states.

The net result is more desireable light per Watt as compared to existing ballast and bulb combinations.

They also claim that their arc maintenance will vastly improve bulb life (a reasonable claim).

[Paul B]

None of your observations contradict the laws of physics

Ok let me see if I can change that. My experiment is completed. I had to cut it short so I did not burn down my house. I have been hearing this thing for years about putting different types of loads into an insulated box and see that it generates the same heat.
Well, it does not. Again, no disrespect to any dead physicics.
I found an incandescent light bulb and an AC motor that use the exact number of watts.
I tested on a $300.00 Fluke multimeter the amps both loads were using and it was .42 amps. The starting temperature in the box was 72 degrees. (the styrofoam box is 2" thick) The glass thermometer was inserted into a tight fitting hole in the box and the motor was put into the box and ran for exactly 30 minutes. The temperature reached 125 degrees and was steady.
Then I cooled off the box until it reached 72 degrees and put in the light bulb.
I had to stop the experiment after 10 minutes because the thermometer reached 155 degrees and it could only go to 160 and I didn't want to explode my thermometer.
Now it could be argued that I did not let the test go long enough and that is a valid concern so I need to find a smaller motor and light bulb but for now I still think an ac motor which is an inductive load does not generate the same heat as a resistive load such as a light bulb.
I feel that the energy that was converted into motion never becomes heat.
I think I can prove that. (I hope Newton or Einstein is not reading this)
If I used my motor experiment and for arguments sake it generated the same heat as the light bulb, then I extended the motor shaft out of the box and used that motion for something like for instance a fan, Then the motor would be using "more" energy than was supplied because besides generating the same heat as the bulb, it was also generating more energy by turning the fan.
I am getting a headache and wondering if I can go back into time when I was a teenager and rub Rogain on my head if I would have hair now.

[110galreef]

Originally Posted by BeanAnimal

I think you got confused somewhere along the way...

It appears (I just browsed) that they are simply claiming that their ballast is a FEW percent more efficient than a standard mag or electronic ballast.

They appear to claim alot more than that. They are in short basically claiming, enery costs inline with that of LED's, given the same or more light output/watt, and about the same lamp life ~ 28000-40,000 HRS per lamp as LEd's, up to 75% dimming. ROI of 1.25 yrs. That is a lot sooner than LED's

Electrical saving comes from the abiltiy to go from current 300w-600w ballast to their 200-250w or your current 1000w-1500w ballast to their 575w/600w/750w ballast or your current 2000w ballast to their 1000w ballast and still have the same amouint of light given these balast squeeze alot more light output from less energy. This is where the savings comes basically cutting the wattage in half and getting the same lumens.

[BeanAnimal]

Originally Posted by Paul B

Ok let me see if I can change that. My experiment is completed. I had to cut it short so I did not burn down my house. I have been hearing this thing for years about putting different types of loads into an insulated box and see that it generates the same heat.
Well, it does not. Again, no disrespect to any dead physics.

No disrespect to you Paul, but if your test does not reflect the first law of thermodynamics, then the test is flawed, not the first law of thermodynamics

Now it could be argued that I did not let the test go long enough and that is a valid concern so I need to find a smaller motor and light bulb but for now I still think an ac motor which is an inductive load does not generate the same heat as a resistive load such as a light bulb.

As mentioned above you are going to have a few very basic problems to overcome with regard to evenly distributing the heat in the box and ensuring that the SAME amount of power is being pumped into the box. You experiment also need to run long enough to allow equilibrium. This may or may not happen depending on the power input vs the power loss to the room and many other factors. Your bulb has a very small mass and therefore stores very little energy as heat. Your motor has a larger mass and therefore stores more heat in its mass. That is why timing the experiment to equillibnrium is important. If the ENERGY INPUT is the same, then the boxes will reach equillibrium temperature at the same time, but get there at different rates. That also means that the box with the bulb would need to have MASS added = to the box with the motor...

That is why I suggested using water and a bucket with a heater and a pump. There are a few less variables to control.

I feel that the energy that was converted into motion never becomes heat. I think I can prove that. (I hope Newton or Einstein is not reading this)
If I used my motor experiment and for arguments sake it generated the same heat as the light bulb, then I extended the motor shaft out of the box and used that motion for something like for instance a fan, Then the motor would be using "more" energy than was supplied because besides generating the same heat as the bulb

Nope

In this case the MOTOR would not heat the box as much because it is TRANSFERRING energy OUTSIDE the box before it can turn to heat INSIDE the box. The spinning fan blade is doing WORK outside of the box and this generating HEAT outside of the box

BTW Paul, can I have some of the steaks that came in that box?

[110galreef]

Originally Posted by Paul B

I tested on a $300.00 Fluke multimeter the amps both loads were using and it was .42 amps. The starting temperature in the box was 72 degrees. (the styrofoam box is 2" thick) The glass thermometer was inserted into a tight fitting hole in the box and the motor was put into the box and ran for exactly 30 minutes. The temperature reached 125 degrees and was steady.
Then I cooled off the box until it reached 72 degrees and put in the light bulb.
I had to stop the experiment after 10 minutes because the thermometer reached 155 degrees and it could only go to 160 and I didn't want to explode my thermometer.

Wouldn't the motor housing be holding a lot of the heat/energy (whatever you want to call it---i am no expert) in that small given time & sample space. Also air sucks a transfering heat. In water I am sure it would be a lot closer in temp. and given a longer time and bigger volume. That air filled box is to small to concur anything...other than the bulb if more effective in radiating heat!

[PowermanKW]

Originally Posted by Paul B

I have one thing none of those dead physists have, a styrofoam box. OK two things, I doubt many of them has an AC motor.
(I also don't know why we are talking about ohm's law either, but I had to take 4 years of it to become an electrician. Total waste of time for an electrician)

Anyway, the problem with these discussions on a fish forum is that physics don't really apply here. OK I know I will have to explain that so Bean does not get a stroke.
Take Neuton for instance. If you take two different weights and climb to the top of the Leaning Tower of Piza and drop them they will hit the ground at the same time. He was wrong and they will not. Maybe on an asteroid that has gravity but no atmosphere that would work but not on earth and being that we live on earth, that theory is not accurate here. Thats why they always end that theory by saying "in a vacuum". We don't have any vacuums here on earth, OK maybe some Electroluxe's, but thats it. (try it with a feather, on earth)

Einstein was another one. Great theory and when my reef tank goes almost as fast as the speed of light, my moorish Idol will not age and he will live forever. But not here on earth and not today because we can't yet go the sped of light and acording to him, we never will. We will probably also never know. It really confuses me when I think of that space ship going the speed of light and wondering why the headlights don't go faster than the speed of light.

As for MH lights heating the water as much or more than LEDs, there are too many variables to test that with physics but I can test it in practice. I can take a 100 watt MH light and put it 6" off some water then do it with LEDs.
One problem is that with MH lights, much of the heat is generated by the ballast so if the ballast is remote, that heat will not be transfered into the water. Then we have the problem of the shape of the lamp. With a MH the lamp is round allowing most of the light to be shed to the back and sides so the quality of the reflector is a factor. LEDs for fish tanks use no ballast but they have reflectors that direct the light downwards.
Both lighting systems put out different wavelengths of light which is also a factor.
I do know, practically speaking that I did have MH for many years and my tank ran about 6 degrees hotter. Now my new LEDs use about a third the amount of power and emit about 25% more light (yes I know this is totally against the laws of physics, but the physicists did not have LEDs or reef tanks) So for me, and I mean no disrespect to the dead physicists LEDs use less power, supply more light and heat the tank much less. This I can show you and prove by letting you put your hand in the water. You can see it with your eyes and feel it with your hands. Of course you can dis prove this with math and OHMs law but my fish do not know OHMs law, they just want to be comfortable.

The only problem we are having here is what we wish to define as the boundary, and what we want to use as our system.

The end result of 100 watts of light energy will be thermal energy... but you are correct that that does not necessarily mean it will be 100 watts of thermal energy to the tank. If we want to define our system as our tank, then some will be lost to the surrounding room.... some of that energy will be lost from the system if there is AC in the room.

The point that I saw picked was that light watts are not thermal watts and indeed they are, because as was explained a watt is just a measure of energy.

But just because that is a true fact, it does not mean that all 100 watts of light energy will be put into the water as thermal energy for many of the reasons you mentioned. But I agree with Bean and he made a valid point.

Same thing that comes up with submersible pumps in water... yes every watt consumed will be converted to thermal energy in the water. So if a pump uses 100 watts then 100 watts of thermal energy is being added to the water directly by work or friction which work will convert to friction in the end.

Lights get a pass because it matters how much heat is lost to the room, how much heat is removed from the room, and how much energy is converted to IR and other wavelengths that are easily absorbed by water over a different light source for comparison.

[Paul B]

then the test is flawed, not the first law of thermodynamics

Dam law of thermodynamics.

You experiment also need to run long enough to allow equilibrium.

Wait, let me check my fire extinguishers.

BTW Paul, can I have some of the steaks that came in that box?

It was probably some sort of fish, and it would cook great. I wonder what the melting point of styrofoam is?

Ok back to the drawing board. Dam physicists.
It's a good thing I am retired and need to get rid of a lot of electrical junk.

Somebody has to test these theories.

[PowermanKW]

Originally Posted by 110galreef

Facts:


•The LED light quality diminishes or dims over the operating lifetime of the LED bulb. This degradation in light should be considered when reviewing the MTBF of LED's since the light emitted at the LED's life start is not equal to the light emitted at the bulbs half-life or life-end. If the LED bulb cannot produce the light output originally specified, it is a form of failure.
•Over time, heat created by LED's also has an adverse effect on the systems light quality and MTBF. Depending on the class of the LED bulb used, factors such as powder coating (filter) degradation and the material used to manufacture the LED lens, further add to the truism that LED's do not necessarily meet their manufacturer's specified MTBF ratings and lighting quality claims.
•DHID equals or outperforms the longevity of LED in most industrial and commercial applications at lower costs. The integrated microprocessor of the DHID doubles the life expectancy of the HID lamp by maintaining full level of illumination up to 28,000 – 40,000 hours and beyond when smart dimming is utilized.
•Studies have proven that DHID used as a direct replacement and mounted at the same distance as the original HID lighting, outperforms LED in many quantifiable measurements of energy efficiency and light penetration. DHID offers a market leading lumens per Watt rating of 116lm/W+ (which is 25% – 30% above LED's lm/W rating) and therefore delivers higher energy efficiency, greater light penetration, and quality light over the entire 40,000+ hours MTBF; and all for a fraction of the cost of LED.

.


LET THE ARGUMENTS ROLL!!
One way or another these new thigs all look promising for cost savings!

The bolded part is what I have always wanted to know. I have not seen any meaningful measurment of light intensity or spectrum shifts in LEDs. We have had MH and fluorescent lights long enough and played with them long enough to know when PAR decreses and output is lost. Generally all light sources do and we don't care when it comes to room lighting, but it does matter for our tanks.

What does it matter if LEDs can last 10 years if the spectrum we first purchaced them for degrades in 2 or 3? Also, with the other factors in real life such as heat and application, if life is decresed and spectrum and output are decreased that much faster, then LED replacement could be quite possible in a relatively short period.. 2-3 years??? Then cost/benefit changes greatly compared to other sources.

[ksc]

You might want to read "The 50,000 Hour Myth" on led degredation. I think 2 years is about right so far for a reef tank led light. Some fixtures much less...

[110galreef]

Originally Posted by ksc

You might want to read "The 50,000 Hour Myth" on led degredation. I think 2 years is about right so far for a reef tank led light. Some fixtures much less...

Thats what scares me about LED's for our SW tanks.

Sure MH's will last 2-3 yrs plus, but not at the PAR & spectrum we want. SImple $60 fix to bring it back to new!

LED's output and color shift test haven't been enuf, plus if they do shift & fall off after say 3-4 yrs, lots of LEDs to replace & resolder on many of the fixtures if they can be replaced. Just not tried & true enuf.

Many on here have shown the SPS tanks can be kept with LED's just have to wait & see how they look 3 yrs out! Plus so many extras to buy to get the color & control you want via your reef controller. The MH's just simple on off at set times! No extras to buy.

[ksc]

Will Your LED Really Last Forever?

Dispelling a Modern Myth

LED manufacturers have been making predictions on LED lifetimes for many years now. Most claim a lifetime to 30% degradation at 50,000 to 100,000 hours. How many of those manufacturers make the claim based on actual testing in the field? The answer is probably lower than you think. In fact, you will have a hard time to find that information anywhere. Manufacturers are hard pressed to deliver results which indicate energy cost savings, replacement labor savings, and environmental friendliness in order to make expensive LEDs more desirable. The claim is controlled conditions, but the truth is controlled conditions that can never be attained except in your grocer's freezer.

Lifetime ratings tend to be based on LEDs, mounted on cooling plates, and typically not in their casing materials. If you ever wondered where the LED curent ratings come from, it's fairly simple to guess at from estimations. Epoxied LEDs must transmit their heat through a low thermally conductive material, meaning they can only have drive currents around 18mA before heating inside causes fast degradation.

Tests of LEDs without any temperature control, and at the recommended manufacturer drive current easily show degradation a majority of the time, and much faster than 50,000 hours of use allows for. These lower power LEDs tend to experience exponential decay, at a rate which is exponentially proportional to the drive current.


If you've ever seen blue LEDs, burnt out pixels, or anything similar, it is likely due to manufacturers providing poor guidance to their end users. I hope this knowledge will help anyone seeking to use or purchase LEDs understand what to expect between reality and the modern myth of indestructible LEDs.

[BeanAnimal]

Folks:

I have called the company linked to above (accendo electronoics) and spent considerable time talking to them regarding our hobby and how we utilize MH ballasts. The product looks very promising but they are IN NO WAY prepared to handle a flood of calls from reefers asking questions.

At the request of accendo, I have agreed to send them information regarding bulb and ballast combinations currently used in our hobby so that they can do some in-house testing, as their firmware is geared more towards 4,000k type bulbs and commercial fixtures. Depending on the results they may be able to make ballasts available to us.

I will post the information back here when (if) it becomes available to me.

To be clear:
They are not equipped to handle an influx of calls from reefers looking for ballasts and are not prepared to give pricing or compatability information without some extensive testing with an array of bulbs we use in the hobby.

[ksc]

I'll let you in on a little secret. I've been comparing the par output between a 250 Radium mh and a Cree par 38 bulb. After 18 months the Radium has lost about 5% less par than the Crees. So, not all led fixtures outlast mh's....

[110galreef]

Originally Posted by BeanAnimal

Folks:

I have called the company linked to above (accendo electronoics) and spent considerable time talking to them regarding our hobby and how we utilize MH ballasts. The product looks very promising but they are IN NO WAY prepared to handle a flood of calls from reefers asking questions.

At the request of accendo, I have agreed to send them information regarding bulb and ballast combinations currently used in our hobby so that they can do some in-house testing, as their firmware is geared more towards 4,000k type bulbs and commercial fixtures. Depending on the results they may be able to make ballasts available to us.

I will post the information back here when (if) it becomes available to me.

To be clear:
They are not equipped to handle an influx of calls from reefers looking for ballasts and are not prepared to give pricing or compatability information without some extensive testing with an array of bulbs we use in the hobby.

I sent them an email. I can report back any info as well.
Thanks,

[BonsaiNut]

Originally Posted by ksc

Will Your LED Really Last Forever?

Dispelling a Modern Myth

LED manufacturers have been making predictions on LED lifetimes for many years now. Most claim a lifetime to 30% degradation at 50,000 to 100,000 hours. How many of those manufacturers make the claim based on actual testing in the field? The answer is probably lower than you think. In fact, you will have a hard time to find that information anywhere. Manufacturers are hard pressed to deliver results which indicate energy cost savings, replacement labor savings, and environmental friendliness in order to make expensive LEDs more desirable. The claim is controlled conditions, but the truth is controlled conditions that can never be attained except in your grocer's freezer.

Lifetime ratings tend to be based on LEDs, mounted on cooling plates, and typically not in their casing materials. If you ever wondered where the LED curent ratings come from, it's fairly simple to guess at from estimations. Epoxied LEDs must transmit their heat through a low thermally conductive material, meaning they can only have drive currents around 18mA before heating inside causes fast degradation.

Tests of LEDs without any temperature control, and at the recommended manufacturer drive current easily show degradation a majority of the time, and much faster than 50,000 hours of use allows for. These lower power LEDs tend to experience exponential decay, at a rate which is exponentially proportional to the drive current.

If you've ever seen blue LEDs, burnt out pixels, or anything similar, it is likely due to manufacturers providing poor guidance to their end users. I hope this knowledge will help anyone seeking to use or purchase LEDs understand what to expect between reality and the modern myth of indestructible LEDs.

I am always a little suspect about general comments regarding any industry that has many market segments and is rapidly changing. Any comment regarding LED's that is based on general statements made "over many years" is in question.

Why wonder? If you have an aquarium fixture running CREE XR LED's, why not just download the technical information from the manufacturer showing expected L70 lifetimes based on junction and air temp? This is what aquarium light manufacturers base their warranties on - they design heatsinks and fans assuming a certain ambient operating temp and a planned mean operating schedule. In this SPECIFIC case, with CREE XR-E LED's, operating at 230F junction temp (HOT) in 185F degree ambient air temp (HOT) L70 lifetime is projected to be 50,000 hours. Run a junction temp of 176F, in an ambient environment temp of 131F, and L70 doubles to over 100,000 hours.

I would personally refer to the above tech spec from CREE, the warranty from reputable light manufacturers, and the real-life experience of reefers who are going on 18+ months now with AI fixtures without a measurable loss in PAR before I would rely on any general "myth debunking" article. Reef lighting is a very specific end use. If you aren't evaluating LED's and fixtures designed specifically for this end use, I question the validity of any LED article - either Pro OR Con.

By the way - this is one reason why (within the reef aquarium industry) Ecotech Marine's design decisions on the Radion fixture are interesting to me. The Radion white LED's are the same white CREE XP-G LEDs used by several other companies. However Ecotech is going to overdrive them at 5 watts (instead of the standard 3 watt). Brighter light, yes. But less efficient, AND possible lifetime issues if they aren't really clever with their heat management.

[ksc]

"the real-life experience of reefers who are going on 18+ months now with AI fixtures without a measurable loss in PAR."

Interesting. Do you have a link to any of these tests? I'd love to see some results using both a spectrometer and par meter. I wonder how many "reputable light manufacturers" warranty their fixtures for 50,000 hours?