Ken
Well we are talking about two different things then. I was referring to the space heating or cooling load. If you are referring to the energy used by the space or building system to maintain setpoints within the buildings zones then you really should build out your system and not use the purchased air model as this is not representative of building energy use.
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alan
--- In EnergyPlus_Support@ yahoogroups. com, ken young <kennethjyoung@ ...> wrote:
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> Seems a little strange that the energy use isn't dependent on the inlet supply temperature. It seems as though you are correct however. Could you expand on that a little?
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> As far as I know "purchased air" is fixed temp air supplied directly to a zone with variable flow rate.
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> --- On Tue, 5/26/09, Alan Jackson <alanjackson7@ ...> wrote:
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> From: Alan Jackson <alanjackson7@ ...>
> Subject: [EnergyPlus_ Support] Re: purchased HVAC
> To: EnergyPlus_Support@ yahoogroups. com
> Date: Tuesday, May 26, 2009, 5:46 AM
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> The calculation for heat loss or gains of a zone are not dependent on the supply air temperature to that zone, more important would be the setpoint temp of the zone.
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> So if you are just looking for a zone load report purchased air will give the same results as a hydronic radiant/convective system.
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> alan
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> --- In EnergyPlus_Support@ yahoogroups. com, ken young <kennethjyoung@ ...> wrote:
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> > As far as I can tell (and I think I read it somewhere) this is what the
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> > "purchased air" model is useful for- determining energy consumption of
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> > a building without all the plant and system bells and whistles.
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> > I think you are correct. The input file specifies the high and low input air temps for a "purchased air" system so the energy usage will depend on how you set those variables.
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> > I'm new at it also so if you find out something else please let me know or post. thanks.
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> > --- On Mon, 5/25/09, kostas ordoumpozanis <ordoumpozanis@ ...> wrote:
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> From: kostas ordoumpozanis <ordoumpozanis@ ...>
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> > Subject: [EnergyPlus_ Support] purchased HVAC
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> > To: EnergyPlus_Support@ yahoogroups. com
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> > Date: Monday, May 25, 2009, 11:25 AM
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> > Hi.
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> > I have modeled a simple building in energyplus (I am new) and i want to apply an hvac system so that i can get the energy looses and gains of each zone.
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> > I read about the purchased HVAC, but i noticed that you give a heating and cooling air temperature. In my case i have a hydronic system (which for now, i don't want to simulate, i don't have the basic energyplus knowledge yet)
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> > Is the air purchased HVAC system correct for just getting the energy looses and gains for the building without any hvac system simulated (due to the fact that this system suppose that you have hot and cold air at specific temperatures, so the results depend on this temperatures)
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> > Thank you
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