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Comparing heating power

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NiHaoMike:

Too bad there's no standardized way to test how much "usable" heat a heater would provide in a typical real world situation. I would expect radiators to do especially poor with high ceilings but work OK with lower ceilings.

wraper:

--- Quote from: NiHaoMike on December 25, 2023, 12:31:23 am ---Too bad there's no standardized way to test how much "usable" heat a heater would provide in a typical real world situation. I would expect radiators to do especially poor with high ceilings but work OK with lower ceilings.

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All of the heat will go inside of the room anyway. But as halogen heater lamp mainly heats through radiation, in close proximity you'll feel warm even if air is actually cold because it heats you directly. All electric heaters are 100% efficient. With larger distance it's not like thermal radiation will be lost, just spread over larger area.

Dacian:

--- Quote from: akis on December 20, 2023, 10:07:31 pm ---I suspect that the Dt50 power of convection radiators is not equivalent to the power of the electrical radiator.

Would anyone know how to compare the two power ratings?

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They are fully equivalent.
If you have any type of electrical heater that uses 2000W it will be exact equivalent of that water filled convection radiators.
Of course if either the electric heater or water radiator has a thermostat that stops the output for say 50% of the time then net energy delivered to room will be that 50%.

I fully heat my house with solar PV so I have embedded copper wires in to the concrete floor that works as in floor heating elements and the floor works as a very large thermal storage about 93kWh
I also have a solar panel installed on a wall and that is also a heater basically made of 60 diodes in series and is directly connected to PV panels installed outside no electronics and it naturally works at the max power point.
I will first concentrate on thermal insulation if you want to improve the comfort of your room. And maybe consider a heat pump if your outside temperature is mild in winter. I'm in Saskatchewan Canada and normally (except this winter) is way to clod here for a air to air heat-pump.

BrokenYugo:

--- Quote from: akis on December 22, 2023, 06:26:23 am ---Central heating, water filled radiators, report their power (in watts) based on the strict condition that [ radiator temp - room temp =  50C, known as "Dt50" ]. To explain this metric, when your radiator is at 70C (average) and your room is at 20C, the difference being 50C, at that precise point the radiator is said to emit 2000W of heat.

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This is the cause of your confusion, DT50 does not specify output, it specifies the test procedure to measure the output of a hot water radiator, which could be anything depending on the size and design.

This paragraph I copied off some UK radiator store's site explains it well.

--- Quote ---Delta 50° (75/65/20) - with Delta T of 50°C, means 75°C inlet water temperature, 65°C outlet water temperature and 20°C of room temperature. The average water temperature in this example is 70°C (i.e. 75° plus 65°, divided by 2).  If we then take the 20°C room temperature we are left with a temperature differential of 50°C or Δt 50°.  This is a typical scenario.
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The idea being that one could cheat and overinflate the stated output by placing the radiator in a very cold room or using hotter feed water, so the conditions are fixed for the sake of fair comparison. The physics of a resistive electric heater are different, the only variable there is watts from the wall, as all power in is converted to heat out. The only way you can really cheat with an electric heater is to cram more heating element in than the heater can continuously dissipate in a typical use case, but a cheap power meter will show that easily.

As others have mentioned, any perceived differences in equal output heaters are down to how the heat is transferred. Radiant usually feels best, the larger the better, like some of the best heat you can get is a machine shop full of big multi ton iron machines, those are always nice in winter, I imagine in floor radiant gives a similar effect.

RJSV:
   My guess is that THERMAL radiation, and even the patterns of I.R. emission matter, especially when it's a complex animal (us humans).  Consider the case where virtually all of I.R. emissions go straight up to roof, while the poor shivering human sits, figgiting with controls, to get more heat.
My guess is that an oil filled vessel radiates in various bands, including I.R. and surfaces are significant to the emissions results, for various optical bands and intensitys.  A reflective chrome coating can have a lot of effect, vs an anodized black coating.  (I couldn't say which is best, but surfaces matter, for electromagnetic emissions.

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