Re: [EnergyPlus_Support] Heating/Cooling Load

["Clemens Felsmann" <felsmann@xxxxxxxxxxxxxxxxx>]

Derek,

I think this is not a problem of  the so-called "equivalent" deltaT. When I
simulate a design day with constant ambient conditions, no sun, no gains no
HVAC-system just a building than I can expect a constant cooling/heating
load, can't I ? This load also should  meet the UAdeltaT.

Clemens

--

Dr.-Ing. Clemens Felsmann
Institut für Thermodynamik und TGA der TU Dresden
Tel.: 0351/463 3 5177
Fax: 0351/463 3 7888
mail: felsmann@xxxxxxxxxxxxxxxxx
----- Original Message -----
From: "Derek McGarry" <derekm@xxxxxxxxxxxxxxxxxx>
To: <felsmann@xxxxxxxxxxxxxxxxx>
Sent: Wednesday, October 30, 2002 3:09 PM
Subject: RE: [EnergyPlus_Support] Heating/Cooling Load


> Clemens,
>
> I do not recall the previous questions and answers, so I hope I am not
> repeating anyone.  Some possible reasons for discrepancy:
>
> For heat transmission through the walls and roof, are you using actual
> deltaT or "equivalent" deltaT?  The equivalent deltaT accounts for solar
> exposure, thermal mass, daily temperature range, solar absorptance of the
> exterior, and probably some other factors as well.  These values can be
much
> higher than actual deltaT.
>
> For heat transmission through the windows, are you accounting for solar
> loads on top of conductance in your manual calculations.  These loads can
> also be much higher than simple UAdeltaT calculations.
>
> I apologize if this is redundant information.
> Regards,
> Derek
>
>
> -----Original Message-----
> From: Clemens Felsmann [mailto:felsmann@xxxxxxxxxxxxxxxxx]
> Sent: Wednesday, October 30, 2002 7:09 AM
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> Subject: [EnergyPlus_Support] Heating/Cooling Load
>
>
> Dear Group members,
>
> the zone heating/cooling load calculation for both steady state conditions
> at design days as well as transient conditions during a run period results
> in values that are 30...400 times higher than a UAdeltaT calculation. The
> previous questions/answers didn't really help.
>
> Attached there is the *.idf file.
>
> Thank you for answer/comment.
>
> Clemens
>
> --
>
> Dr.-Ing. Clemens Felsmann
> Institut für Thermodynamik und TGA der TU Dresden
> Tel.: 0351/463 3 5177
> Fax: 0351/463 3 7888
> mail: felsmann@xxxxxxxxxxxxxxxxx <mailto:felsmann@xxxxxxxxxxxxxxxxx>
>


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