So why can't I buy a halogen home boiler anywhere?

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Old 05-09-12, 04:51 PM
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So why can't I buy a halogen home boiler anywhere?

Dear Anyone.

I can buy halogen room heaters. Or even halogen ovens. They both cost a fraction of the money to run that conventional electric heaters/ovens cost. Wonderful.

So why can't I buy a halogen boiler to heat my hot water? Surely all someone would have to do is take an electric water heater, chuck the element out the window and put a halogen bulb or 3 in instead? And get the voltage right, of course, but you see what I'm getting at? Surely that's not so hard?

As this is a D.I.Y. site, could I do it? I mean, I can buy halogen bulbs. I have an electric boiler that heats all my hot water. What's stopping ME from swapping its element for a couple of halogen bulbs (or so, I'd work it out properly first) and saving a small fortune on water heater bills?

Yours puzzledly

ulrichburke
 
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Old 05-09-12, 05:06 PM
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Because it's just not efficient You can't put a halogen bulb in contact with water.

The items you mentioned use the radiant heat generated to do their job.

I don't think they are really a fraction of the cost either...unless its a fraction like 3/4...lol. They aren't LEDs.

I don't know much about boilers...but most either apply flame directly to the vessel. I assume electric has the element in contact with the water?
 
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Old 05-09-12, 05:10 PM
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Ulrich, if it would work, and it was that simple, it would be done already.

Fact is, you need BTUs to heat water, and the air in the home. You can't heat stuff without energy.

A few halogen bulbs won't produce the amount of energy you need. There's no way around that.

The reason the halogen and quartz heaters seem so efficient is that they are not heating the air in the room, they are heating the PEOPLE by using the RADIANT energy. Basically, they are 'beaming' the heat right at you and keeping you warm by reducing the heat loss of just your body by bathing you in radiant heat energy.
 
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Old 05-09-12, 05:13 PM
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I assume electric has the element in contact with the water?
Hi Vic, yes... there are actually multiple high wattage elements, much like a water heater element. They are 'staged' or 'sequenced' by an onboard controller. Depending on the 'delta T' , they might turn on one or some or all the elements.
 
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Old 05-09-12, 05:33 PM
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But the halogen ones wouldn't have to be. Read on...

Dear Gun-guy.

Firstly, in an electric kettle and in an electric boiler you've got electrical elements directly in the water. Water, as you know, conducts electricity well - the only reason the immersion works is because the elements are coated, as far as I know, or else you'd risk electrocution every time you turned the kettle on!

You wouldn't have to have the halogen bulbs IN the water, though I don't honestly see why an element surrounded by glass is so much more dangerous when immersed than a coated electrical element. (I know I'm not an expert in this field, so I bet I get a ton of people explaining that one to me!)

Imagine you had a pipe with the water going through it. You could have the perfectly dry Halogen bulbs in rows surrounding the pipe. Or you could have a heat exchanger between the bulbs and the pipe. Wouldn't those ideas work?

Yours puzzledly

ulrichburke
 
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Old 05-09-12, 06:02 PM
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Actually..pure water is a poor electrical conductor....it's the minerals and such that make it a possible hazard when around electricity. High school chem experiments taught me that.

As I said..not sure how boiler and water heater elements are constructed...but the current carrying conductor is probably completely insulated from the water...not just coated...AFAIK.

Glass...even quartz glass would not like the extreme heat of a halogen element on one side and cold water on the other. So no way they could be in direct contact.

As NJT said..radiant heat is how halogen bulbs work. Not the most efficient form of heat transfer.
 
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Old 05-09-12, 06:54 PM
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Ulrich, let's run a few numbers.

It takes 1 BTU to heat 1 pound of water 1 degree.

Your home let's say has a heat loss of 50,000 BTU/hour. (worst case, coldest day)

Let's guess that there's 25 gallons of water in your heating system.

Water weighs approximately 8 pounds per gallon.

The water from your boiler might need to be 180F to heat your home.

The man in the green house owns the Zebra. (paying attention? )

1 KILOwatt of electricity equals 3410 BTU.

Presume that we are heating 25 gallons of water ( 200 pounds ) from 70 to 180. That's a 110 temperature rise.

Therefore, to heat 200 pounds of water up 110, it would require 22000 BTU.

Dividing the 22K BTU by 3410 BTU/KW tells us that one would require an energy transfer of 6.5 (appx) KILOwatts.

Let's say that you are using what, 50W Halogens? 6500 divided by 50 is ONE HUNDRED AND THIRTY bulbs.

Ummmm... that's a little unreasonable, don't ya think?

And that's just to heat the water up ONE TIME. As the water circulates through the system and is giving off heat to the home, that water will need to be constantly RE-heated, right?

Further, if your home requires heat replacement of 50,000 BTU/hour then THAT is how many light bulbs you would really need. 50000 divided by 3410 is 14.5 KW. Even if you could use 1000 watt bulbs, you would still need 15 of them. That's enough to light a stage at a rock concert!

Repeating what has been said already, the RADIANT energy that is beamed at your body is NOT the same process as that which is required to transfer energy into circulating water. It's a completely different physical process.
 
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Old 05-09-12, 07:35 PM
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"Imagine you had a pipe with the water going through it. You could have the perfectly dry Halogen bulbs in rows surrounding the pipe. Or you could have a heat exchanger between the bulbs and the pipe. Wouldn't those ideas work ?"

Air being a pretty good insulator would make the heat transfer from the halogen tube to the water pipe. Have you ever seen what happens to a quartz halogen radiant tube when you splash a drop of water or two on it whilst it runs at full power ? It ain't pretty.

The real efficient way to use electricity to heat water is thru a heat pump, steal energy from the air or the ground and use electricity to move that energy into the water, not to just create the energy alone.
 
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Old 05-10-12, 05:06 AM
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The real efficient way to use electricity to heat water is thru a heat pump, steal energy from the air or the ground and use electricity to move that energy into the water, not to just create the energy alone.
Exactly. Ground source heat pumps are very efficient.

My brother has a stove that uses infrared to heat his pots. It is the most awful stove I have ever used. If you have shiny pots, forget it. It will take 30 minutes to boil water. God forbid the pot isn't covering the "light bulb" all the way because it will blind you.
 
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