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[EnergyPlus_Support] Re: AirTerminal:SingleDuct:Uncontrolled
Hello Dr. Li,
Can you please send the attachment to my email, because i cannot access it from here, and didn't receive any email with the attachment.
In fact the building is large. I am only studying for now the implementation of HVAC systems, for now I wanted to control one zone and understand the various aspects of the parameters. Then I shall escalade and implement more hvac systems and condition all the zones.
I had previously in this order: mixing box + water:cooling:coil + water:heating:coil + supply fan, but could not setup the setpoint manager so that the zone air meam temperature was in the 20/25ºC range. I had defined at the both coils sensores (at the controller) the supply fan outlet node, but then in implementing the setpoint the system didn't stay in the 20/25ºC range. Then I changed the sensor of the cooling coil to the output of the cooling coil node and the heating coil to the supply fan outlet node, with this I achieved the range 20/25ºC but with an extra 0,7ºC possibly from the supply fan heat rejection that the system didn't account for. For this I setup 2 setpoint managers one singleZoneHeating and one singleZoneCooling. Because of the extra 0,7ºC I changed the supply fan to be before the heating coil, and with this I got perfect 20/25ºC as I pretended.
But I could only achieve this in defining an Outdoor Air Flow in the Sizing:Zone sufficiently big, if I leave it at the default at 0.00944 m3/s (flow/person) then the system cannot achieve the 20/25ºC, then I checked the nodes mass flow and saw that it was constant all year round, and should be varying to supply the required air amount to achieve air mean temperature of the zone to the thermostat setpoint range of 20/25ºC.
Could explain why this is happing or what is it that I am doing wrong?
After this, the next step for me will to implement heat recovery systems.
Best regards,
Vieira
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, YuanLu Li <yli006@...> wrote:
>
>
> Hi, Vieira
> I am still frying to figure out what is the relationship of the controlled zone to the rest of the building.
> The attached .csv is the result of your second up loaded IDF.
> You will see that some of the zones have very high temperature.
> The position of the fan in the air loop should not affect the performance much. However, you need to state blowthrough or drawthogh in one of the fields, and node connection sequence must match. I have not found these yet.
> The building is quite large. It will take some time for me to identify all the locations.
> How many AHU do you intend to use in the final design? One AHU per floor for many zones, and one fan coil unit per zone would have different branch arrangements.
>
> Dr. Li
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> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> From: vieira.jose99@...
> Date: Wed, 30 Mar 2011 15:26:39 +0000
> Subject: [EnergyPlus_Support] Re: AirTerminal:SingleDuct:Uncontrolled
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> Hello,
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> Thank-you for your help xszhang2010.
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> I just had to adjust the set point manager to get 25ºC maximum during the cooling season. I changed the supply fan to be before the heating coil, because the way I had it (water cooling coil then water heating coil then supply fan) I could not get a decent setpoint manager setup for the water:coil controllers.
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> I also added a return fan.
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> But now I have another issue with the variable fans. They are not varying!? I don't understand why not. Also to get temperatures in the 20 to 25ºC range all year round, I had to force in the Sizing:Zone the option Outdoor Air Method to a reasonable flow or else the system doesn't achieve de 20ºC minimum in winter and passes the 25ºC maximum in summer. I think it is because the Fans are not varying there flow to a greater value of air flow, as I said the air flow is at a constant level.
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> I have put the .idf in the file section, here is the link: http://tech.groups.yahoo.com/group/EnergyPlus_Support/files/_Problem_Submittals/
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> Best regards to all,
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> Vieira
>
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