Infrared Maths Problem!!!

nixander

Hi all!
After hours of research, I have decided that the best form of heating for my home will be numerous infrared panels placed around the room. However, now I am in the process of purchasing the panels, I am stuck with a bit of a dilemna. Either it's the hours of brain-frazzling research (not likely), or just my general IQ (most probably), but I can't seem to work out which sized panel would be most efficient considering the wattage needed. How do I get the most 'bang' for my 'buck'? ...and if possible, please detail the formula used to form such a conclusion!
Thanks so much!

Below are the details...

Panel A - 600x600mm - 370w - produces heat of 125c
Panel B - 900x600mm - 575w - produces heat of 125c
Panel C - 1200x600mm - 780w - produces heat of 125c

Cardew

Welcome to the forum.


If you don't know the answer to the question you posed, how have you concluded('after hours of research') 'that the best form of heating for my home will be numerous infrared panels placed around the room.'?


All of the rooms in a property will have heat loss. In order to maintain an internal temperature of 'x' degrees when the outside temperature is 'y' degrees it will need 'z' kW.


The criteria for calculating this heat loss depends on size of room, insulation properties, windows, floor etc. There are loads of calculators to be found on the web. This is an example:


http://www.heatlosscalculator.co.uk/


However it is most important for you to realise that the heat input required is the same regardless of the heat being supplied by gas, oil, LPG, solid fuel or electricity.


If we take electricity, with the heat input required being say 2kW, it doesn't matter what form of electrical heating you use.


You can have radiators filled with water/oil/clay, fan heaters, panel heaters, granny's old 1/2/3 bar electric fire or infrared panels.


It doesn't matter if each electrical heating device costs £10 or £1,500 it will cost exactly the same to keep the room at 'x' degrees when using electricity at the same cost. If any of those heaters use, say, 1kWh they will produce EXACTLY the same amount of heat.


The above applies equally to infrared heaters. However the advantage of infrared heating is that it beams heat toward the object(a person in a domestic situation) and thus the person receives the benefit of that warmth, without needing to heat the whole room.

nixander

Thanks for your reply.

I should have made myself more clear in stating that each panel (a,b,c) is infrared. So whilst I spent many hours researching the type of heating I'd prefer, it didn't enlighten me as to the size of panel that is most efficient (although I understand that all electrical heaters are 100% efficient) - this is where I am stuck.

You see, I understand that 1kw of power will always produce 1kw of heat energy (unless the heater has a light or LCD panel also), yet when I calculate the efficiency of each panel, I get different results. Let me explain.

If I calculate the area of panel heated by 1 watt, I get this result for panel A...

600mm x 600mm = 360,000mm ÷ 370w = 973

This means that 1 watt from this panel will heat 973mm (sq) of panel

Yet 1 watt from panel B only heats 939mm (sq)

This means that panel A is the better option because it heats more of the panel using less wattage?

I think this is right?

Thanks!

Cardew

nixander wrote: »

You see, I understand that 1kw of power will always produce 1kw of heat energy (unless the heater has a light or LCD panel also), yet when I calculate the efficiency of each panel, I get different results. Let me explain.

If I calculate the area of panel heated by 1 watt, I get this result for panel A...

600mm x 600mm = 360,000mm ÷ 370w = 973

This means that 1 watt from this panel will heat 973mm (sq) of panel

Yet 1 watt from panel B only heats 939mm (sq)

This means that panel A is the better option because it heats more of the panel using less wattage?

I think this is right?

Thanks!

Firstly it doesn't matter if a heater has a light, fan or LCD panel, they will produce the same amount of heat.


It seems to me that you are not looking at the principle of infrared panels correctly. Their purpose is not to heat the panels themselves(like a radiator) but to radiate heat.


For a given output of heat, the size of the panel determines the 'intensity' of the 'beam' of heat. By that I mean if the 780w heater (Panel C in your first post) was(to give a stupid example) 'transmitted' via a 10mm x 10mm panel instead of 1200mm x 600mm, you would have an intense beam that would be more suited to welding than warming humans;)

Compared to traditional heating systems, Infrared panels can provide human thermal comfort at lower ambient temperatures, meaning less energy is required to reach comfort levels. By heating occupants directly, such systems reduce the amount of heat wasted through infiltration and air movement.

An analogy would be lighting. I could sit at a desk in a huge room and a low powered desk lamp or single spot lamp would provide sufficient illumination for reading, but not adequate lighting for the rest of the room.

Infrared heating has been in use for many years. As said in other threads, it is used to beam heat toward someone working at a bench in an unheated garage. Or before Central Heating became widespread an infrared heater was often used in an unheated bathroom.

nixander

Understood! Thanks so much for your help and advice. I'm guessing that the size of the panel doesn't really matter then, it just depends on the size of the room that you require to 'heat'? However, I do understand that they don't necessarily heat the room, just heat objects within the room, which then radiate heat as a consequence.