infrared heating

[imok2]

The question is: Is infrared heating cheaper and more efficient then radient or gas because some Mfgs make that claim.For example if you generate 90,000 btu from infrared and use 22.6 Kw and you generate 90,000 btu from radient and use 22.6 Kw the claim is that infrared is cheaper because the efficiency is better. I know the type of heater used makes a difference but they are using quartz instead of ceremic. Plese help me understand!

 

[IRstuff]

> I would consider infrared to be "radiant," so not sure what's up with that.

> Hypothetically, infrared could be more efficient, compared to convective heating, but only if you assume that the target has a high absorbtion. Say, in your example, 90kBTUh at 80% absorbtion = 72 kBTUh transferred to the target. With a convective heater, you'd be dumping 90 kBTUh into the air, and hoping to get some of it into the target, but clearly, the bulk of the heat will never reach the target, having already been consumed within the room, or chamber.

TTFN

FAQ731-376

 

[imok2]

Maybe the following is the best answer I can find from Electroic heating Assoc.:

The function of an electric infrared ‘Total Area’ heating system is to supply the right amount of heating where needed to maintain a constant desired comfort level. An effective heating system brings the room surfaces and air up to temperature and holds them constant despite changes in outside air temperature or variations in heat losses. If the infrared equipment is carefully selected and properly installed (to project heat downward in a uniform distribution pattern over the floor area), excellent ‘Total Area’ heating efficiency can be expected

 

[rmw]

Based on the numbers that you gave, irrespective of how each gadget works if they produce 90K btu with 22.6kw they have the same efficiency. 22.6kw if it comes from the same source costs the same. The power system just bills you for 22.6kw and doesn't know what you are doing with it.

Now if the question is effectiveness, does the space seem warmer, or are the habitants more comfortable (using the humidity vs sensible temperature relationship of A/C as an example) then it might be a different matter. Not much radiant or IR heating is done in my world so I don't have a feel for how each feels or how one might feel when in their presence.

But efficiency wise, it is a wash.

rmw

 

[IRstuff]

Depends on how the "efficiency" is defined. Efficiency in the broadest sense is the amount of net result for a given input. If you define the "efficiency" to, say, something like net Joule heat of an object relative to plug power on the heater, then you can get different answers than from the ratio of heater output relative to plug power.

Obviously, this is all highly dependent on the POV of the person doing the calculation, and the desired output of the calculation. As a systems engineer, it's the net result that matters, i.e., it doesn't necessarily matter that you have 99.9999% efficiency in one part of the system if there's a 0.00001% efficency somewhere else, particularly if there's another system that has even a net 0.01% end-to-end efficiency.

Therefore, in the OP, while the two systems may have the same unit efficiencies, it will be cheaper to use one in practice than the other, because its output is more efficiently coupled to the target.

TTFN

FAQ731-376

 

[MintJulep]

IRstuff pretty much has hit the target.

The infrared heating manufacturers are trying to make a tie-in to thermal comfort levels. The mean radiant temperature of the environment, and difference in radiant temperature of floor, walls and ceilings, is an important factor in comfort.

So the IR heating people are probably defining "efficiency" as the energy input required to maintain a given comfort level over a period of time.

Using that definition, for some building constructions, IR may be more efficient than other options. For other constructions, maybe not.