TV Heat Output.. Plasma VS LCD VS LED VS DLP - Page 2  

I used to live in a top floor old apartment WITHOUT INSULATION and a few weeks in the summer it would get close to 100f. The rest of the year it's fine, and I hate AC, but my ole TV would be like a heater so in those days I grind it and leave the TV off to save me from exhaustion!

vote: LED edge-lit.

He didn't explicitly say "problem" but this was his implicit intent to see if he would have one by choosing one tech over another.

It's a legimitimate question to ask. It's not reasonable to expect strangers to give an answer of any practical value. Just read the post above yours unless truisms and hedge words like "depends" are acceptable.

That makes no sense. He wants to know what tech produces the LEAST heat. The answer is led as most people who voted know and that is an ANSWER (and the correct one). Just because you say its not of practical matter is irrelevant. For someone who is already at 100 degrees its relevant for some one who has AC but is broke its relevant for many its not but that is not the POINT!

my vote was for LED as I believe it puts out the least amount of heat given the choices

would it be a problem in the room? I don't think any of us can answer that

but a simple test can be run: plug in a light bulb with approximately the same wattage of the display you are considering: leave it on for a few hours as you would viewing a TV: this will simulate the heat output of the TV

Mark,

Your answer is spot on. Just like mine in Post 28 so I beat you to it. Quoting myself:

That question can be answered by bringing into the room a lamp and two bulb, one 150W and another 300W, to simulate an LCD and a plasma. As the average human body dissipates about 100W doing nothing, the test should require that the person or persons be there during the test. As watching a lamp glow is not very intellectually stimulating, a good book would be helpful.

The problem is with defining the "problem". This is so subjective nobody can answer this but the OP himself so coming here with a question like this is a waste of time.

This makes you and me the smartest responders in this thread so far.

you did beat me to it: sorry I missed that


I would not disagree with you on this point, but others may

The very fact that there is a CORRECT answer turned this "poll" into a knowledge test as all tests are.

A poll is meant to collect public opinion: Do you prefer blondes or brunettes? A survey asks for objective data: How many people live in your house? A test is meant to check the knowledge of facts of those being tested: What is longer - a foot, 18 inches or a yard?

This "poll" is a knowledge test and your comment about an anwer being correct confirms it.

Instead, in lieu of running his own test per Mark's suggestion, the OP would be better served by getting the power consumption data from the specifications sheets of the sets on his, hopefully, short list and asking for an opinion: Guys, do you think x watts in my 12 x 12 room will really matter to how it feels?

Let's for a moment go with the flow and agree that LEDs are the least power hungry. So what? Without knowing the actual watts, followed by a simple experiment, the conclusion could be wrong if, hypothetically, the LEDs draw 100, the LCDs 110, and the plasmas 120. Legally and technically speaking LEDs win. Practically, this information is completely and utterly useless.

This thread for real? I've owned em all. LED hands down wins this debate. There isn't even a real reason to push as to why. It's pretty clear why....

... and they will. Just give it a little time.

Correct! However the poll shows that some are misinformed and this is a way to educate them (if its never discussed, taught or written about how will the masses learn?) So it helps the OP CREATE his list with a certain tech in mind IF he wants to minimize heat output. It was useless to YOU but perhaps not to the next person who does not know or care to read every spec sheet. Now they can feel good about a tech without having to know the underlying reasons. You and I may want to know those reasons but please don't assume the masses who may search google and come up with AVS as a hit don't want an answer at the tech level and not the underlying level.

THANK YOU!!!!!

The reason is not what may be important to someone who simply does not know and wants to know which tech produces the least amount of heat!

I would think the smartest would not get the first law of thermodynamics mixed up with the principle of Conservation of Energy.

Nor would they make a point of writing that "All of the power consumed will be dumped into the room as heat. The tiny amount radiated as light will also convert into heat." and then correct them self by writing that the room is not 100% efficient and some (admittedly small) escapes the room and claiming they where right "correct. Almost".

...and they did. Nitpick.

I don't think you see my point. It is not all dumped as heat into the room the work produced is subtracted. So the work light and sound is subtracted from the internal energy to get heat output. Yes much of that work will then turn back to heat but it was not dumped into the room as heat it was dumped into the room as work. Now comes the efficiency part since the room is no where near 100% efficient that will escape the room and be turned into heat elsewhere.

I couldn't put it any better! And that's exactly what I meant. Now you became one of the three smartest posters in this thread. Welcome to the club.

lol. No way. I am a jack of all trades and master of none. Nature of my job and I like it that way.

You quoted Wikipedia, and yet didn't answer my question. Dielectric heating only works on polar molecules, and is significantly more effective on water than on any other substance. Because fats and sugars have polar properties on a localized level (the molecules themselves are non-polar), they can be heated by microwaves but with much less efficiency.

Back to my original question, the glass tray that came with my microwave and all of my dishes have yet to melt or even get warm when put in the microwave alone. Where does all this energy go if it is not being transformed into heat?

a magnetron requires proper loading in order to operate at full power: if there is no water or dielectric to load it properly, I think the output of the magnetron is reduced: similar to a VSWR sensor reducing transmitter output to an antenna if it detects a high VSWR

why are we discussing microwaves in an AV forum?

point taken and I will issue an infraction to myself if you insist, but I find it an interesting discussion

lol, just busting your chops Mark.


http://www.eng-tips.com/threadminder.cfm?pid=239

Sorry, the issue came up and it's more of a fun discussion for me. If it's too off topic I'll drop it. I figured the original question has been answered and unanimously agreed upon, so I figured it wouldn't hurt to continue with other side issues that have come up.

Naw, it's no big deal one way or the other to me as I was just giving Mark a bad time (hopefully he saw it in a good natured way) as it was perfectly set up by him.

Hey no problem

My business is cooling of high power electronics (high power to me starts at 5kw and up to 500kw) and sometimes I get carried away

Mark

One of the benefits from discussing laws of physics is that, in the end, reasonable people will have to come to a common point - regardless where they were at the beginning of the discussion - where they agree as physics, math, etc., as opposed to politics and social issues, and not tolerant of "diversity" of views.

For that reason, the AVS forum is a good place to visit.

I think it was on topic. You don't, which is fine. The subsequent discussion could lead some critical readers to see the path I was attempting to lead down. I mean no harm by this, just that I had a specific intent.


First of all, if I'm addressing you, I'll address you. So your initial query that I quoted back to you has no answer... but your subsequent exposition makes me wonder why you asked it.

If you put the glass in the microwave, the microwave radiation is absorbed primarily by the air inside the microwave I'd guess, since modern microwaves are fairly reflective internally, as is glass. But the energy is out there and it can't go nowhere. Water is good at actually absorbing the microwave energy and converting it into molecular motion and moving water molecules are the source of the warming for the food you put in there. But the energy is out there once it's out there, which is part of why they tell you not to run your microwave with nothing in there -- it can get bad.

I used the phrase "very basic physics," in a post; you quoted that and immediately followed it by the statement "energy can neither be created nor destroyed, only changed in form." I'm not confused whether you were addressing me, as you clearly quoted me. I am confused as to why you quoted the conservation of energy in response to my statement that not all energy is converted to heat in any given situation.

Mark has already partially addressed my other question - without a dielectric in the field of a magnetron to create a load, the magnetron puts out less power, thus decreasing the need for excess energy to be dissipated.

HogPilot, all due respect here, you're still confused.

In "very basic physics", energy can not be created or destroyed.

It can't.

If a device consumed 200 watts of electrical energy, it has to emit 200 watts of something. Period.

If there's less power output from a magnetron, so be it, then there was simply less power consumed by the magnetron in the first place.

If a TV consumes 200 watts, it will have to output 200 watts of heat, light and sound -- somehow, some way. If a TV consumes 400 watts, it will have to output 400 watts of heat, light and sound -- somehow, some way.

That's very basic physics, and it makes not one whit of difference if there's an LCD panel, a plasma panel, a DLP, or a giant array of men with candles inside the TV. If we know the wattage going in, we know what's coming out.

What we debated on the side is the ratio of light energy to power consumed in the various technologies. And someone with a better understanding of the physics than I can explain the difference between diffuse light energy being converted to heat versus the TV radiating heat directly from its electronics. But it's wrong -- no matter how many people keep typing out fancy words -- to suggest that these concepts are not directly related to one another.

Rogo: What are people debating here--is it that displays shouldn't be inefficient--or that displays shouldn't emit too much heat--or that if picture quality is superior then we shouldn't be as concerned with the waste of energy?

I'm all for using the least amount of energy as possible. I'm for the best looking picture as possible.

If it got down to one or the other I'd side with picture quality if my electric bill didn't go up by more than 25%--I'm sure some people would go with smaller percentages than me and for some the thought of their electric bill increasing any amount is unacceptable.

Course some radicals out there might prefer that modern society and its uses of energy would cease to exist completely.

Energy good use or energy bad waste sometimes are hard to calculate.

Nobody has ever been able to answer this question here--say if you had a 8X10 room with 9 foot ceiling.

If nothing but a plasma TV were in the room--how much could that plasma set increase the temperature of the room?

I've always wondered with all the scientific engineering genuises around here at AVS why at least one of them could give us an answer?

One last thing: I'm glad to see you posting Rogo. You are a living legend! Is it true that you and about 10 other posters here at AVS really know everything there is to know about video?

It seems you are the one that is confused. I have never once disagreed with what you've stated above, and your statement has nothing to do with the point that I'm making about how electromagnetic energy can be dissipated aside from being transformed into heat.