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taharvey
Posts: 57
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 Posted: Thu Feb 02, 2006 1:20 am Post subject: Adjacent to ground bug |
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When I set the walls to "Adjacent to Ground", it disappears from the "heating design" graph of losses, from the HVAC requirement design calculation, and from the fabric losses in the simulation.
So a house with basements end up with unrealistic loss and HVAC calculations. How to fix? |
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taharvey
Posts: 57
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| Posted: Fri Feb 03, 2006 4:35 am Post subject: |
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| Also, when a wall is set "Adjacent to Ground", the external wall construction type disappears from the construction tab. ?!? |
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Andy Tindale
Posts: 1110
Location: Stroud |
| Posted: Fri Feb 03, 2006 7:51 am Post subject: |
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| Quote: | | When I set the walls to "Adjacent to Ground", it disappears from the "heating design" graph of losses, from the HVAC requirement design calculation, and from the fabric losses in the simulation. |
The default ground temperature is 16°C so the heat loss through surfaces adjacent to ground will be much lower than heat losses through surfaces adjacent to external air (and may appear be zero). The DesignBuilder default ground temperature is most appropriate for large buildings where the ground temperature 0.5 m below the building is typically 2°C lower than the average building internal temperature (EnergyPlus engineering reference document).
I think that this probably explains the results you're seeing. You may want to change these default ground temperatures defaults if you think the temperature of the ground on the other side of your surfaces adjacent to ground should be lower in your case.
We will be addressing the way ground temperatures are defined in future 1.x versions this year.
| Quote: | | Also, when a wall is set "Adjacent to Ground", the external wall construction type disappears from the construction tab. ?!? |
This has now been fixed and ground adjacences work much more smoothly. The fix will be released in version 1.0.2 in the next few days and I will let you know when the new version is ready.
Regards
Andy |
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taharvey
Posts: 57
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| Posted: Fri Feb 03, 2006 8:39 am Post subject: |
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Andy,
I did set the ground temperatures lower. In fact I set them to their minimum allowed value just to test the heating design tab. The graph bar disappears altogether, and isn't calcuated in the heating design calcs at all. |
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Andy Tindale
Posts: 1110
Location: Stroud |
| Posted: Fri Feb 03, 2006 8:45 am Post subject: |
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Please try version 1.0.2 when it is released - you should find that this problem has gone away.
Just to be double sure could you send in your model so I can check that it works with the new version?
Thanks
Andy |
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