Emulating thermal mass and lag time
Emulating thermal mass and lag time
(OP)
Hello all,
We are testing a heater unit in a climate room.
The climate room, however, is pretty bare and has minimum wall insulation. Therefore, whenever the heater is off, room temperature drops like a stone, which creates an unreal condition, since houses lose heat at a slower rate.
What would be your thoughts on emulating a thermal mass, as in an actual home/house?
We did consider adding furniture to the room, but it is a small room and that would make testing difficult.
I'm thinking of stacking in a few dozen water drums, since water has a high heat storage capacity.
Any suggestions are appreciated.
We are testing a heater unit in a climate room.
The climate room, however, is pretty bare and has minimum wall insulation. Therefore, whenever the heater is off, room temperature drops like a stone, which creates an unreal condition, since houses lose heat at a slower rate.
What would be your thoughts on emulating a thermal mass, as in an actual home/house?
We did consider adding furniture to the room, but it is a small room and that would make testing difficult.
I'm thinking of stacking in a few dozen water drums, since water has a high heat storage capacity.
Any suggestions are appreciated.





RE: Emulating thermal mass and lag time
RE: Emulating thermal mass and lag time
RE: Emulating thermal mass and lag time
macmet, the test room is very restricted by surrounding structure and cannot be modified.
gadkinsj, I should have mentioned that this is a storage heater, so we don't want to influence the room temperature directly. However we know that the current drop is not realistic and that affects the performance of the heater.
RE: Emulating thermal mass and lag time
TTFN

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RE: Emulating thermal mass and lag time
We are trying to quantify the performance of the heater, i.e. how much heating it delivers and how fast it can bring the room temperature to the required comfort level.
The room temperature drop (say overnight, when the heater is off) needs to be a realistic one to simulate that of a house. Currently it is not, which puts more demand on the heater to bring the temperature back up again.
Since we cannot change the climate room structure, we need to introduce a thermal mass that will absorb and retain heat when the heater is on, and slowly release this heat back to the room when the heater is off.
I hope this explains the nature of the problem.
RE: Emulating thermal mass and lag time
You could also look for phase change materials
http://www2.basf.us/corporate/080204_micronal.htm
RE: Emulating thermal mass and lag time
Thanks ione.
I think for now water is the cheaper option.
May be a long term solution would be to use PCMs to give the climate room some artifical, but permenant, thermal mass.
RE: Emulating thermal mass and lag time
Again, if you are running the "climate room" uncontrolled, that's a bad testing concept. If it is controlled, then there should be no reason not to ramp the room temperature to what you want. Seems to me that using another of your heaters set to the minimum allowable room temperature would be adequate, unless you have not fully described your test.
TTFN

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RE: Emulating thermal mass and lag time
Thanks everybody for your suggestions.
We are revising the climate room build and how it can be modified to create a more realistic thermal mass.
RE: Emulating thermal mass and lag time
I think that 55 gallon drums concentrates the heat too much in one location to be very accurate. I would think that lots smaller containers of water spread out would be a better simulation of a higher thermal mass.
I would also think that the temperature outside your litle room would have a big impact on the heat load. As well as # of windows and "wind" real or simulated.
This seems more like a simulation problem than a problem where you can build a lab inside. Maybe give away a couple of units to people in Wyoming for a test.
Regards
StoneCold
RE: Emulating thermal mass and lag time
I'm not sure about the cycling involved in your testing, but will you have to heat up the large masses of water each time as well?
RE: Emulating thermal mass and lag time
It seems that our current room does not meet BS 60531, which is specifically created for testing storage heaters. A new room will be built with dimensions and insulation as per the spec.