Drawbacks? -- Purely-Natural Gas-Fired Blue-Flame Infrared Radiant Heater

[Green Xenon]

Hi:

 

I’m thinking of hypothetical purely-natural gas fired radiant heater in which the significant emitter of thermal radiation is the flame itself. What would be the disadvantages of this heater?

 

The fuel is purely-natural gas. By “purely natural”, I mean it is the raw, unprocessed, and unrefined natural gas straight from the marshes. In terms of oxidant/fuel ratio, the flame is stoichiometric. Oxygen [O2] is the only oxidant to burn the fuel.

 

Each and every molecule of the fuel is fully-oxidized by the oxygen but without there being any excess of oxygen.

 

There are 6 sides to this radiant heater. Left, right, back, front, up, and down. The height of the left, right, front and back are the same. The top and bottom are shorter in length than the heights of the aforementioned. However, the top and bottom are of the same width as the widths of the left and right. The front of the heater is what faces the object intended to be heated. The front consists of eco-friendly material that is completely transparent to all EM radiation from 100,000 nm to 300 nm. The interior of the back of the heater consists of eco-friendly material that completely reflects all wavelengths of EM radiation from 100,000 nm to 300 nm. The interiors of the left and right of the panel also consist of eco-friendly material that totally reflects wavelengths of EM radiations from 100,000 nm to 300 nm. The bottom of the panel is where the flame is emitted. The length of the flame is almost as long as the bottom of the panel. The top of the panel is where hot gases from the combustion escape – this is the exhaust and is as long as the flame. The material on the front of this heater has a low-enough heat conduction coefficient that it remains perceptibly cool even though it allows thermal radiation to escape outward.

 

There are two pipes attaches to the bottom of this heater. One carries the fuel, while the other carries a stoichiometric amount of oxygen.

 

This infrared heater is air-tight prior to combustion. Also, prior to combustion, the only gas present in the heater is helium. Helium is an easy-to-transport, non-reactive gas. There is a sufficient amount of helium [but not more] such that the air pressure inside the heater equates to the air pressure outside the heater – this is to prevent any damage to the heating panel caused by pressure differences. Just before ignition of the fuel, the correct amount of helium is removed such that the high-temperature of the flame does not raise the internal air pressure to the point of damage. Also, the ignition is smooth and completely non-explosive. Just prior to the ignition, an adequate amount of fuel and oxygen are discharged into the heater in the slow, smooth, continuous manner. Now, when the amount of fuel [and stoichiometric amount of oxygen] is enough for ignition and self-sustaining combustion, an electric spark is discharged which causes the fuel to catch fire. The amount of flame is adjustable in terms of height and width – however the length is constant. At the lowest setting there is just enough flame for the blue to be visible. At the highest setting the flame nearly fills up the entire heating panel.

 

I’m thinking of two applications for this radiant heater:

 

1. Use mild versions of the heater in cold parts of the world in outdoor public places to keep citizens warm – such as in the bus stops in Northern Europe, where the climate is often cold and wet.

 

2. More intense versions of this heater can be used to cook food. Think charred pork that’s bloody red on the inside.

 

 

Thanks,

 

Green Xenon

[John Cuthber]

Once again, you seem to have come up with an idea that is somewhere between impossible and impractical.

 

The helium is expensive and pointless.

Gas flames are not very good emitters of IR.

Separating oxygen from air requires a lot of energy and wouldn't achieve much (as far as I can see the only benefit would be that it would prevent formation of NOx fumes; it might slightly increase the radiation efficiency).

 

What's wrong with a patio heater or a gas powered grill?

The biggest problem with bus shelters is, I believe, vandalism. Your suggestion wouldn't help that.

[Danijel Gorupec]

Green Xenon, what problem are you trying to address with such device? Why is it important to use purely-natural gas? Why it must be filled with helium prior to ignition?

 

(BTW, transporting "purely-natural" gas through pipes seems harder than transporting methane-ethane-only mix. Propane and Butan are prone to liquification under pressure or low temperature and it is difficult to transport something that is part liquid, part gas. Clean combustion of such wide mix also seems problematic to me.)

 

 

[CaptainPanic]

I’m thinking of hypothetical purely-natural gas fired radiant heater in which the significant emitter of thermal radiation is the flame itself. What would be the disadvantages of this heater?

There would be no disadvantages. It would be awesome. It would be better than any modern heaters because of a number of reasons:

 

• You propose to use the dirty unrefined natural gas, while modern heaters use cleaned natural gas. Of course we also assume that transportation of the unrefined natural gas is no problem, which doubles the awesomeness and also doubles the hypotheticality.

• You propose that you have mostly thermal radiation, while modern heaters do exactly the same. This makes your hypothetical invention just as awesome as any random gas powered heating device in any house. Of course, you somehow (hypothetically) overcome the heat resistance of the metal casing, and emit heat directly from the flame straight through the casing which will severely reduce the heat transfer coefficient. That would (hypothetically) mean that your exhaust gases will be colder, and this increases the efficiency... which gains you several awesomeness points.

• Your wonderful (hypothetical) invention combusts all gas in a perfect blue flame without the need for any excess oxygen, which is already incredibly awesome in itself. If you ever manage to do this, just forget the rest of the heater, and patent the super efficient stoichiometric natural gas combustor. Anyway, it will increase the temperature of the flame, and therefore your invention beats the modern heaters hands down. It's very awesome.

• The use of helium, the reason why you use it remains unclear to me, is a very nice touch. It gives an extra *zing!* to the invention. I would suggest to use the words "nano" and "green" too in your next invention

 

In short, there are no disadvantages to your idea... but that's as long as you ask our opinions about hypothetical devices. As soon as we enter the realm of Real Things, I can see a few problems challenges.

[Moontanman]

Do you mean something like this?

 

http://www.mrheater.com/product.aspx?catid=42&id=23

 

I have one, it is great for outdoors and in my garage. The one I have runs on propane but it could easily run on methane, it has no flame, just a very hot radiant beam of heat.

[Mr Skeptic]

As usual, your idea has some awesome but impossible parts, and some crappy parts which may or may not be possible. In short, your idea is impossible, and if it were possible then a better device could be made by disregarding some of the extra restrictions. You can copy/paste this to the various other suggestions you've made to date.

 

For this one in particular:

Impossible:

Complete combustion of molecules.

Material completely transparent to EM radiation, eco-friendly or not (if only due to impurities, and yes same goes for only a certain band of EM).

Non-explosive explosive ignition as described.

 

Impractical:

The radiation being from the flame itself rather than a proper blackbody emitter.

Limiting the oxygen to only what is stoichiometrically necessary for combustion, since that would result in additional unburnt fuel and some unreacted oxygen, rather than slightly more unreacted oxygen and a more complete combustion.

Use of dirty gas, rather than having it cleaned and the non-fuel components removed for a cleaner and more efficient flame.

Wasting helium as described.

 

Practical:

Using radiant heat transfer.

[Green Xenon]

As usual, your idea has some awesome but impossible parts, and some crappy parts which may or may not be possible. In short, your idea is impossible, and if it were possible then a better device could be made by disregarding some of the extra restrictions. You can copy/paste this to the various other suggestions you've made to date.

 

For this one in particular:

Impossible:

Complete combustion of molecules.

Material completely transparent to EM radiation, eco-friendly or not (if only due to impurities, and yes same goes for only a certain band of EM).

Non-explosive explosive ignition as described.

 

Impractical:

The radiation being from the flame itself rather than a proper blackbody emitter.

Limiting the oxygen to only what is stoichiometrically necessary for combustion, since that would result in additional unburnt fuel and some unreacted oxygen, rather than slightly more unreacted oxygen and a more complete combustion.

Use of dirty gas, rather than having it cleaned and the non-fuel components removed for a cleaner and more efficient flame.

Wasting helium as described.

 

Practical:

Using radiant heat transfer.

 

Okay, I would like to make one change to my hypothetical radiant heater: use oxygen instead of helium so that there is no unburned fuel at all. There maybe more changes as I think things through.

 

Why is it is impractical to use the flame directly as an infrared emitter? Don't all hot objects -- including fire -- emit IR?

Edited January 24, 2011 by Green Xenon

[Fuzzwood]

Yes but the flame also emits a lot of light, which can also be converted into IR if some of the excess energy is absorbed into the material, which will again be released as heat. Forgot the details of that tho, but it is comparable to the phenomena that heated iron will glow with a reddish white glow.

[John Cuthber]

I still rather suspect that most of the heat from a flame isn't emitted as IR.

It's easy enough to check.

Place your finger and inch to one side of a candle flame and see how hot your finger gets. then repeat the experiment with your finger an inch above the flame.

Because the distance is the same the amount of radiated heat should be (near) the same.

I suspect that you will rapidly accept that convection , mixing and conduction are a significant loss path.

Feel free to do this with any other flame you like.

 

As Mr sceptic says, using IR transfer is practical; but it's damned inefficient.

 

I'd still like to know where you are going to get the pure oxygen from.

 

Seriously, why do you think your idea is better than this?

http://www.calor.co.uk/outdoor-living/patio-heaters/

[Green Xenon]

I'd still like to know where you are going to get the pure oxygen from.

 

Seriously, why do you think your idea is better than this?

http://www.calor.co.uk/outdoor-living/patio-heaters/

 

 

1. Where do I get pure oxygen from?

 

I wish I knew.

 

2. Why is my idea better than that in the link?

 

It isn't. I'm just pondering about hypothetical technology.

 

Speaking of which, I'd like to make another change to this device: let's use oxyhydrogen instead of natural gas. Let's also make sure there is no excess hydrogen. Excess oxygen is okay so long as it doesn't damage any of the equipment.

[John Cuthber]

Can we have it designed and built by magic pixies who don't need to follow the rules of physics?

[Mr Skeptic]

If concentrated oxygen is OK, then an oxygen concentrator would be sufficient, and comparatively cheap and efficient, compared to using pure oxygen. Especially since using pure oxygen would be so expensive and inefficient.

[CaptainPanic]

It isn't. I'm just pondering about hypothetical technology.

In all fairness, it's a number of other people on this forum that do most of the pondering for you. You're at best dreaming.

 

Speaking of which, I'd like to make another change to this device: let's use oxyhydrogen instead of natural gas. Let's also make sure there is no excess hydrogen. Excess oxygen is okay so long as it doesn't damage any of the equipment.

It's not a device. It's a hypothetical situation. Devices are REAL. Stop confusing us. You got already nearly a hundred replies on this forum - most of those replies are very practical, because you confuse us into thinking that you actually want to build something. You don't. You just want to dream, and to think of hypothetical situations.

 

What bothers me the most about your way of behaving on this forum is that you just throw random ideas at us... and then you wait. They always sound practical (like you change the fuel - as if that matters in a hypothetical perfect combustion process). Then we say what's wrong with it, and instead of learning anything about the real world, you just come up with a new random hypothetical idea.

 

It's completely OK to talk about hypothetical stuff... scientists do it all the time. But the goal should be to learn... and you seem to fail at this point.

 

The other reason to do any scientific work might be to build something, or to invent something... but that's never hypothetical. That's REAL. But the things you describe are not becoming more real as we proceed. They remain just as hypothetical as always.

 

In fact, I don't see the point of all your threads anymore.

Edited January 26, 2011 by CaptainPanic

[Green Xenon]

In all fairness, it's a number of other people on this forum that do most of the pondering for you. You're at best dreaming.

 

 

It's not a device. It's a hypothetical situation. Devices are REAL. Stop confusing us. You got already nearly a hundred replies on this forum - most of those replies are very practical, because you confuse us into thinking that you actually want to build something. You don't. You just want to dream, and to think of hypothetical situations.

 

What bothers me the most about your way of behaving on this forum is that you just throw random ideas at us... and then you wait. They always sound practical (like you change the fuel - as if that matters in a hypothetical perfect combustion process). Then we say what's wrong with it, and instead of learning anything about the real world, you just come up with a new random hypothetical idea.

 

It's completely OK to talk about hypothetical stuff... scientists do it all the time. But the goal should be to learn... and you seem to fail at this point.

 

The other reason to do any scientific work might be to build something, or to invent something... but that's never hypothetical. That's REAL. But the things you describe are not becoming more real as we proceed. They remain just as hypothetical as always.

 

In fact, I don't see the point of all your threads anymore.

 

 

I'm very sorry for the annoyance. From now on, I will think a *lot* more before I make any future post. I will keep my dreams to myself as they are a nuisance to others.

[John Cuthber]

If concentrated oxygen is OK, then an oxygen concentrator would be sufficient, and comparatively cheap and efficient, compared to using pure oxygen. Especially since using pure oxygen would be so expensive and inefficient.

 

In my experience of burning stuff to generate heat, using air is cheap and efficient, much more so than using oxygen.

 

Using (relatively) pure oxygen is sometimes a good idea, but it serves no real purpose here. (for a given definition of purpose)

[CaptainPanic]

In my experience of burning stuff to generate heat, using air is cheap and efficient, much more so than using oxygen.

 

Using (relatively) pure oxygen is sometimes a good idea, but it serves no real purpose here. (for a given definition of purpose)

Some people consider oxy-fuel combustion to reach higher temperatures, which means a higher efficiency can be achieved in a steam cycle or carnot heat engine.

 

But if you just want to heat a house, I totally agree that there is no added benefit, other than a *bling* factor.