Green Building Forum - Thermal modelling heat loss through solid floors Tue, 09 Jun 2026 12:59:08 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 Thermal modelling heat loss through solid floors https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128118#Comment_128118 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128118#Comment_128118 Fri, 30 Dec 2011 16:09:09 +0000 Mike George http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8333&page=1

So as not to hyjack that discussion, thought I'd copy the relevant bit here. It would be good to see what others have concluded]]> Thermal modelling heat loss through solid floors https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128119#Comment_128119 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128119#Comment_128119 Fri, 30 Dec 2011 16:12:06 +0000 Mike George Posted By: Mike George
Posted By: joe90 Tin and Mike, I think there are quite a few of us on this forum that would like to see the results of your modeling/expertise in this field. I know there is no one right answer for all occasions but benefits of certain materials/methods would be beneficial knowledge for us.


Hi Joe,

Not sure you will be thanked by many for re-opening this particular can of worms. Our findings were rubished by many [but not proven to be so]

It's not really relevant to suspended floors either but the 2nd BFF article is here http://www.buildingforafuture.co.uk/spring06/25-50.pdf Page 28]]> Thermal modelling heat loss through solid floors https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128121#Comment_128121 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128121#Comment_128121 Fri, 30 Dec 2011 16:13:56 +0000 Mike George http://www.buildingforafuture.co.uk/spring06/25-50.pdf]]> Thermal modelling heat loss through solid floors https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128125#Comment_128125 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128125#Comment_128125 Fri, 30 Dec 2011 16:47:26 +0000 JSHarris Thermal modelling heat loss through solid floors https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128137#Comment_128137 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128137#Comment_128137 Fri, 30 Dec 2011 18:15:44 +0000 Mike George ]]> Thermal modelling heat loss through solid floors https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128151#Comment_128151 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128151#Comment_128151 Fri, 30 Dec 2011 21:33:47 +0000 brig001 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2926&page=1#Item_0
but I think there might be a newer thread somewhere as that one is mostly about Tony's old house.

Anyone know where it is?]]> Thermal modelling heat loss through solid floors https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128155#Comment_128155 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128155#Comment_128155 Fri, 30 Dec 2011 21:50:37 +0000 SteamyTea Thermal modelling heat loss through solid floors https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128163#Comment_128163 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128163#Comment_128163 Sat, 31 Dec 2011 00:13:21 +0000 fostertom Thermal modelling heat loss through solid floors https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128164#Comment_128164 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128164#Comment_128164 Sat, 31 Dec 2011 02:20:46 +0000 tony Thermal modelling heat loss through solid floors https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128169#Comment_128169 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128169#Comment_128169 Sat, 31 Dec 2011 08:28:01 +0000 JSHarris Thermal modelling heat loss through solid floors https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128172#Comment_128172 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128172#Comment_128172 Sat, 31 Dec 2011 10:42:36 +0000 TimSmall
2D only tho', which can be a pain with some details (e.g. sloping roof to wall junction). If you're going to attempt to use it, then google for the tutorials - there are a couple of handy screencasts...

I've done part of a Fakro rooflight cross-section (looking at different flashing options), and have some wall and floor details in-progress.

I'll try and post some results here in the next couple of days...

Tim.]]> Thermal modelling heat loss through solid floors https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128175#Comment_128175 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128175#Comment_128175 Sat, 31 Dec 2011 11:03:51 +0000 JSHarris Thermal modelling heat loss through solid floors https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128241#Comment_128241 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128241#Comment_128241 Sun, 01 Jan 2012 11:49:18 +0000 borpin Posted By: JSHarrisOK, I'll try and stick as many sensors in as I reasonably can. The data is bound to be useful to someone and it may well help me to determine how accurate the fabric heat loss predictions I have are against reality. The cost of the sensors is low, the main challenge will be getting the wiring tough enough to stand up to conditions on site during the build, I suspect. I'm intending to do the same so any feedback on this will be useful.]]> Thermal modelling heat loss through solid floors https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128278#Comment_128278 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128278#Comment_128278 Mon, 02 Jan 2012 00:48:40 +0000 mike7 Thermal modelling heat loss through solid floors https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128296#Comment_128296 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128296#Comment_128296 Mon, 02 Jan 2012 09:55:35 +0000 Mike George Thermal modelling heat loss through solid floors https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128298#Comment_128298 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128298#Comment_128298 Mon, 02 Jan 2012 10:00:09 +0000 SteamyTea
Only got halfway through reading your articles, but shall try and do the rest soon.]]> Thermal modelling heat loss through solid floors https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128338#Comment_128338 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128338#Comment_128338 Mon, 02 Jan 2012 16:34:57 +0000 Mike George Posted By: SteamyTeaNot of a floor slab, but could be something to do when I have a spare 5 minutes:wink:" alt=":wink:" src="https:///forum114/extensions/Vanillacons/smilies/standard/wink.gif" >

or 5 years :bigsmile:]]> Thermal modelling heat loss through solid floors https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128350#Comment_128350 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128350#Comment_128350 Mon, 02 Jan 2012 17:37:50 +0000 SteamyTea
Or as I once said in a tongue twister moment, "partial solutions to differential equations".

There is always the geometric method, shall have a ponder about that. Physicists just love a sphere, no corners :wink:]]> Thermal modelling heat loss through solid floors https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128383#Comment_128383 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128383#Comment_128383 Mon, 02 Jan 2012 19:13:08 +0000 mike7 Posted By: Mike GeorgeNo one else done any computer modelling of floor slabs then?

I had a go using Excel a while back, spurred on by Tony's efforts with heat storage. I could only simulate 2D or 3D solids of revolution - ideal for lighthouse builders - but it worked well enough for my purposes and gave me a better idea of how heat flows throught the ground. It was cumbersome to use and easy to make errors, plus I lacked the computer knowhow and motivation to take it any further.]]> Thermal modelling heat loss through solid floors https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128529#Comment_128529 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128529#Comment_128529 Tue, 03 Jan 2012 20:56:43 +0000 Timber
Just for fun I have done similar sorts of calcs using therm, just to 'get a feel' for this sort of thing. I looked at wing insulation and other things, and it does make a good improvement, but I don't have any actual number results. I spent more time looking at the pretty colours!]]> Thermal modelling heat loss through solid floors https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128536#Comment_128536 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128536#Comment_128536 Tue, 03 Jan 2012 21:48:45 +0000 Jeremy S http://www.cfd-online.com/Wiki/Codes - ELMER and OpenFOAM look like good contenders for modelling heat transfer (conductive, radiative, convective) through solids, as well as fluids.

Admittedly, ST's 5 minutes is more likely to be 5 weeks or months - but would furnish skills that could transferred to many of the problems debated within this forum. I think I need to 'retire' early...

(thanks djh - I'm not here often enough to remember how to HTML/text links consistently...)]]> Thermal modelling heat loss through solid floors https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128540#Comment_128540 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128540#Comment_128540 Tue, 03 Jan 2012 22:16:38 +0000 djh
Posted By: Jeremy Ssee:http://www.cfd-online.com/Wiki/Codes">CFD online- ELMER

To make a working link, you need to just put a URL and then select text mode when you post (or save your edit)

Also, you can't mix quotes (HTML mode) and links (text mode).]]> Thermal modelling heat loss through solid floors https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128544#Comment_128544 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128544#Comment_128544 Tue, 03 Jan 2012 22:46:58 +0000 Paul in Montreal
See page 193 onwards of http://www.nrel.gov/docs/fy08osti/43388.pdf for a description of how BASECAL and BASEIMP (the models used in esp-R and hot2000) work and what the modeling assumptions are in terms of water table, slab thickness etc. These numerical models have been validate against real buildings over multi-year periods.

Natural Resources Canada has made the BASECALC program available for download on its own: http://canmetenergy-canmetenergie.nrcan-rncan.gc.ca/eng/software_tools/basecalc.html


See also: http://www.esru.strath.ac.uk/Programs/ESP-r_capabilities/3Dcond.html

Paul in Montreal.]]> Thermal modelling heat loss through solid floors https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128616#Comment_128616 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128616#Comment_128616 Wed, 04 Jan 2012 16:47:10 +0000 Mike George
I realise we discussed this before but the main discussion was [i believe] on the old forum which is now long gone.

Having spent several years attempting to accurately model heat flow through solid ground, one of the limitations to the results I obtained were that they were limited because certain aspects of the software use had to be fudged. For example the affect of perimeter insulation/wing insulation. The importance of such fudges in terms of their affect on results is a moot point. A further limitation was [is?] the inabilty of the software to model the affects of ground temperature over several rather than a single year.

So my interest here, Is to see any conclusions others have reached, rather than re hashing what was discussed previously.]]> Thermal modelling heat loss through solid floors https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128618#Comment_128618 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128618#Comment_128618 Wed, 04 Jan 2012 17:00:45 +0000 Paul in Montreal Posted By: Mike GeorgeI realise we discussed this before but the main discussion was [i believe] on the old forum which is now long gone.

The post I re-posted was from 2010 on this forum.

Posted By: Mike GeorgeThe importance of such fudges in terms of their affect on results is a moot point. A further limitation was [is?] the inabilty of the software to model the affects of ground temperature over several rather than a single year.


If you search for esp-r and ground heat flow modeling, there are quite a few papers that come up. I have a hunch esp-r (or maybe it was RETSCREEN) was used to model the Drakes Landing Solar Community's ground store too.

Paul in Montreal.]]> Thermal modelling heat loss through solid floors https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128619#Comment_128619 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128619#Comment_128619 Wed, 04 Jan 2012 17:02:02 +0000 Paul in Montreal http://www.docstoc.com/docs/25013469/EnergyPlus-Testing-with-IEA-BESTEST-In-Depth-Ground-Coupled-Heat]]> Thermal modelling heat loss through solid floors https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128622#Comment_128622 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128622#Comment_128622 Wed, 04 Jan 2012 17:25:12 +0000 Mike George
This is also a moot point, as it comes down to how important the limitations are, and whether or not making allowances for them [by fudging] is acceptable.

As I am no longer doing thermal modelling, my interest is more curiosity rather than anything else and is limited to what I can glean from other peoples conclusions, rather than the heavy reading you posted.]]> Thermal modelling heat loss through solid floors https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128623#Comment_128623 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128623#Comment_128623 Wed, 04 Jan 2012 17:29:25 +0000 Paul in Montreal
Really, I just wanted to point out that there is still interest in this area and I think it will only grow as people create more passive-like buildings which incorporate some kind of ground storage.

Paul in Montreal.]]> Thermal modelling heat loss through solid floors https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128779#Comment_128779 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128779#Comment_128779 Thu, 05 Jan 2012 18:01:37 +0000 SteamyTea Imagine it is a cube with x,y,z dimensions being equal.
Most of the losses are at the heat input end, gradually diminishing as the cube gets bigger (volume to surface area getting greater. The Delta T is currently set at 1K. R-Values are between 0.05 W.m^-1.K^-1 and 2 W.m^-1.K^-1, or somewhere between Aerogel and Concrete. If it looks right, and if anyone can verify it even better, I shall try and work out a way to allow irregular shapes to be calculated.]]> Thermal modelling heat loss through solid floors https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128781#Comment_128781 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8344&Focus=128781#Comment_128781 Thu, 05 Jan 2012 18:43:21 +0000 Ed Davies
Thems not R-values, thems k-values.

http://en.wikipedia.org/wiki/Thermal_conductivity]]>