I donâ??t recommend setbacks with most radiant floor heat. You heat a lot of mass before you start heating air and then your mass keeps heating air when you think you want to cool off. You would probably use less energy with a lower air temperature, constant heat. Again it is improved occupant perception of comfort (personal heat balance) and not air temperature that makes this economical.
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I also think E+ may oversize systems based on warmup. You have to force system settings to get a typical 30 minute warm up in an air model.
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(been to busy to keep up with most of this thread) Â Â
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Ned Lyon, P.E. (MA, WV)
Staff ConsultantSIMPSON GUMPERTZ & HEGER
781.907.9000Â main
781.907.9350 directÂ
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www.sgh.com
Send FilesFrom: EnergyPlus_Support@
yahoogroups.com [mailto:EnergyPlus_Support@yahoogroups.com ]
Sent: Friday, December 22, 2017 3:00 PM
To: EnergyPlus_Support@yahoogroups.com
Subject: Re: [EnergyPlus_Support] Re: Radiant Floor vs Forced AirÂ
Â
German,
There is more to modeling radiant system than I imagined.Â
After more review, some assistance from Javed Iqbal (who also posted in this thread) and various associated corrections, the differences between the systems have come into closer alignment with my expectations. the heated floor now performs somewhat better than the forced air system.
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Your chart revealed a very helpful way to view the difference in performance between the two systems. I thank you for that! In the past, I have reviewed results primarily using tabular data and only recently have I begun using charts. It takes some practice to understand well what the charts represent, but I'm enjoying the new insights and becoming better at choosing which data to display.
Â
Merry Christmas to you and your loved ones.
Â
On Mon, Dec 18, 2017 at 3:30 PM, ecoeficiente@xxxxxxxxx [EnergyPlus_Support] <EnergyPlus_Support@
yahoogroups.com > wrote:Â
Hi Jim, my two cents:
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I see clearly different air temperature curves. Heated floor model is not fast enough to reach setpoint temperature during the day while keeps temperature drop rate during the night.
I think that the contained not met loads is due to the ZoneControl:Thermostat:
OperativeTemperature object in the heated floor model idf. Removing it, not met hours get duplicated (being based on air temperature). Â
Just looking at the temperature curves I can imagine that the difference in heat consumption is proportional to the areas I've painted in red and yellow in the results for air temperature:
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Regards,
Â
GermánÂ
Â
--
Germán Campos
Â
--
James V Dirkes II, CEO / President
The Building Performance Team Inc.
1631 Acacia Dr, Grand Rapids, MI 49504Â
(alphabet soup of efforts for greater understanding: PE, BEMP, BCxP, LEED AP)
Direct / Mobile: 616.450.8653
jim@buildingperformanceteam.com
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