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RE: RE: Re: Re: [EnergyPlus_Support] RE: RE: Calculated design heating load difference

What was the error?

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, <energyplus_support@xxxxxxxxxxxxxxx> wrote:

I managed it. Now, although i have heating system in model, calculated heat load is not changing.

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, <energyplus_support@xxxxxxxxxxxxxxx> wrote:

If you are using v8, you may get some ideas from the sensible heat load balance table in the allsummary report.

On 5 September 2013 13:47, <marko.ignjatovic1980@...> wrote:

Ckecked. No outdoor air is entering Ideal Loads system. When I excluded infiltration results fully complied with the design project for transmision. Then I "assumed" that the difference between project and simulation is due to infiltration. For each zone I recalculated required flow of infiltration air. When I entered those values, model (ideal load) and project were matched in design heating load. The problem occurs when I introduce heating system.
The key question is whether HTML file gives demand or final energy? If it gives demand it should remain unchanged.


Suggest outputing outdoorair flowrates and infiltration.

IdealHVAC method has 2 ways to bring in outdoor air. Check:
- no economizer
- minimum outdoor air = zero

Mit freundlichen Grüßen- Sent from my iPhone (excuse the brevity)

i. A.
Jean Marais
b.i.g. bechtold

On 05.09.2013, at 11:49, <marko.ignjatovic1980@...> wrote:


There are no outdoor air objects, since the building has simple hydronic heating systems without OA. Why is the indoor temp fluctuating during the design day? Shouldn't it be constant (In schedules I made All WinterDesignDay related fields at constant values and for equipment to be on all day)?

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, <energyplus_support@xxxxxxxxxxxxxxx> wrote:


--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, <energyplus_support@xxxxxxxxxxxxxxx> wrote:

Hi guys,

I'm having trouble in finding the reason why there is a difference in calculated design heating load for my models. This is the problem. Both models have the same building with the same envelope and same WinterDesignDay schedules for indoor temperatures for sizing. In first model i used IdealLoadsAir system and the obtained design heating loads comply with the real buiding. But when I modeled HVAC systems, there was a great difference in calculated heating load. As we all know design heating load for zone is not dependent of HVAC systems serving it, but is function of envelope properties, interior and exterior conditions. Does any of You have  any idea what could be the cause for this difference. I double checked all common objects for both models and they are the same.

Thanks in advance



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