Ufh Running Test

[Rizzle from the Portizzle]

well have been told all sorts about ufh so decided to test for my self i wanted to know the difference
between a 10mm tile and a 4.8 mm tile so i got 2 x 1 m2 mats from thermonet then used 12mm insulation boards laid the mats out then tiled one side with 4 600x600 10 mm tiles the other side i tiled with 2x 1200x600 4.8mm tiles total area 1.44 m2 then we had to make a roof and walls to cover the area to be tested
to keep the cold draughts out .
next we set the thermostat to 39 % to see how long each would take to get there and how much energy was needed. then we turned them down to 23% and let them run for 3 days so we could compare the difference.
a big surprise for me was how fast the 10mm tile cooled down compared to the 4.8mm .
here are my findings .we used a 3I warm up stat so we could record the results .

day 1 heat up to 39% 10mm tile 6.3 hours 6.8 kw energy used
day 1 heat up to 39% 4.8 mm tile 4 hours 3.9 kw energy used

day 1 heat up including turning down to 23% 24 hours 10 mm tile 9.41 kw energy used
day 1 heat up including turning down to 23% 24 hours 4,8 mm tile 5.82 kw energy used


day 2 running at 23% 24 hours 10 mm tile 6.41 kw energy used
day 2 running at 23% 24 hours 4.8 mm tile 6.03 kw energy used

day 3 running at 23% 24 hours 10 mm tile 6.41 kw energy used
day 3 running at 23% 24 hours 4.8 mm tile 5.59 kw energy used

total energy used 10mm tile 22.22 kw at 10p a kw £2.22 m2
total energy used 4.8 mm tile 17.61 kw at 10p a kw £1.76 m2

here are some pictures

 

[Spud]

nice test there Ray

 

[Chalker]

Nice test ray.
But you are testing how much heat a tile will hold.
To heat a space is a known formula. INSULATION IS THE KEY. That will retain the heat in the room.

 

[SJPurdy]

Results for day 1 are as expected; it requires more energy to heat up the thicker tile than the thinner one as there is more mass to heat to the selected temperature.
Assuming the set temperatures are the floor temperature readings the results for day 2 and 3 are not as I would expect because the heat/energy input only has to match the heat lost from the surface; so all other things being equal they should be the same (*). Other factors may include different: surface colours; surface roughness/finish; extra uninsulated surface area of the edge of the thicker tiles; floor thermostat (possibly difference in resistance at a given temperature).
(*) If tile acting as an insulator then thicker tile should require less energy to hold at the set temperature.

My brain hurts and now stuck on a parapet 🙂

 

[Old Mod]

Results for day 1 are as expected; it requires more energy to heat up the thicker tile than the thinner one as there is more mass to heat to the selected temperature.
Assuming the set temperatures are the floor temperature readings the results for day 2 and 3 are not as I would expect because the heat/energy input only has to match the heat lost from the surface; so all other things being equal they should be the same (*). Other factors may include different: surface colours; surface roughness/finish; extra uninsulated surface area of the edge of the thicker tiles; floor thermostat (possibly difference in resistance at a given temperature).
(*) If tile acting as an insulator then thicker tile should require less energy to hold at the set temperature.

My brain hurts and now stuck on a parapet 🙂

What about tile density Steve?
Wouldn't the tile with greatest density retain heat better?

 

[jobdone]

Thank for spending the time and trouble for this. Solid facts are great to convince customers about long term gains of insulation, and of the difference between tiles in cost.

 

[SJPurdy]

What about tile density Steve?
Wouldn't the tile with greatest density retain heat better?

I just put down the things that came to mind not a total list. I was just cautioning against taking the results from days 2 and 3 to only be due to the difference in tile thickness.
A tile that retains heat better will show up on a test that measures just that: i.e. how long it takes to cool down when the heat source is removed/switched off.
My thinking is that the heat/energy required to maintain a steady temperature (maintain not heat up to) should be the same for both the tiles if they were the same material, colour, surface finish etc. because the energy input only has to match the energy lost at the surface. We are looking at a reasonably heat conductive material (for this purpose) and the thickness is not so large that there will be a significant difference between the surface temperature and that measured in the adhesive bed.
I could be missing something because it is a long time since I have done any physics!

 

[Old Mod]

I just put down the things that came to mind not a total list. I was just cautioning against taking the results from days 2 and 3 to only be due to the difference in tile thickness.
A tile that retains heat better will show up on a test that measures just that: i.e. how long it takes to cool down when the heat source is removed/switched off.
My thinking is that the heat/energy required to maintain a steady temperature (maintain not heat up to) should be the same for both the tiles if they were the same material, colour, surface finish etc. because the energy input only has to match the energy lost at the surface. We are looking at a reasonably heat conductive material (for this purpose) and the thickness is not so large that there will be a significant difference between the surface temperature and that measured in the adhesive bed.
I could be missing something because it is a long time since I have done any physics!

I was just curious Steve, nothing more than that.
Appreciate you taking the time to reply.