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Airloop doesn't work

asked 2018-01-04 06:08:12 -0600

Fernando's avatar

updated 2018-01-04 10:26:13 -0600

I have a datacenter that consumes 18 kw. For cooling I created a loop for water:image description Also I created a loop for air: image description

The simulation crash and gives me the following error:

 ** Severe  ** AirLoopHVAC VC_DATACENTER has no air flow
 **   ~~~   ** Check flow rate inputs for components in this air loop and,
 **   ~~~   ** if autosized, check Sizing:Zone and Sizing:System objects and related inputs.
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answered 2018-01-04 07:46:26 -0600

Avi's avatar

As it reads you don't have air inlet. You need to darg AirloopHVAC:OutdoorAirSystem from the library to the upper left part of the plant. Later I guess you can set outside air to zero if that is what you need.

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answered 2018-01-04 08:19:49 -0600

You don't need an AirLoopHVAC:OutdoorAirSystem at all.

The problem is that your loop is probably autosized, and it's getting sized to a zero flow. That can happen for a variety of reasons.

Check that the zone you serve does have a high cooling load (check the equipment and the schedules attached to it). Check that the zone also has appropriate thermostat setpoint schedules (eg 40F heating / 80F cooling). Also double check the Airloop Sizing:System and the zone Sizing:Zone inputs. And check the SetpointManager you placed on your AirLoopHVAC.

Note that if the only thing you're trying to cool down is a single zone, I'd suggest not using an AirLoopHVAC at all, but one of the ZoneHVAC object that can use a Coil:Cooling:Water (PTAC for example, or 4 pipe FCU)

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I considered a load of 500w/m2 and cooling setpoint temperature of 25ºC.What is the most recommended setpoint manager?

Fernando's avatar Fernando  ( 2018-01-04 08:38:43 -0600 )edit

Cooling down a space with 25°C is unusual to me, and if you didn't change the sizing:system and sizing:zone, it certainly doesn't match the default values. I'd say 55°F if you use a scheduled one. Otherwise, if you're trying to only cool down, you can use a SPM:SingleZone:Cooling.

Julien Marrec's avatar Julien Marrec  ( 2018-01-04 08:47:00 -0600 )edit

I assume you meant a zone temperature set point of 25C. For water coils (for example used in fan coil units), the SPM:SingleZone:Cooling will place the operating set point temperature at the outlet node of the coil (you need to specify this node name in the SPM object). If a draw through fan is used, specify the SPM control node as the fan outlet node and then used a mixed air SPM to place the fan heat adjusted set point at the outlet of the water coil. For other HVAC systems (e.g., ZoneHVAC:PackagedTerminalAirConditioner or AirloopHVAC:Unitary:Furnace:HeatCool) you wouldn't need the SPM.

rraustad's avatar rraustad  ( 2018-01-04 08:58:47 -0600 )edit

I did what you said. I put FCU unit, Temperature setpoint 15ºC, heating batery always off, but I get air temperature very high, like 100ºC. I think the fancoil doesn´t work.

Fernando's avatar Fernando  ( 2018-01-04 09:14:43 -0600 )edit

Is the FCU turning on?

rraustad's avatar rraustad  ( 2018-01-04 10:27:28 -0600 )edit

answered 2018-01-04 16:17:55 -0600

Fernando's avatar

updated 2018-01-05 05:50:14 -0600


The three images show the datacenter's cooling system (chiller, fan coil), where the consumption is 18 kW. The air temperature obtained of the simulation is greater than 100 ° C. What´s is Wrong?

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Change the sizing to Autosized and see what happens.

rraustad's avatar rraustad  ( 2018-01-04 18:24:56 -0600 )edit

I change and I get the same the air temperature. Can I send the .idf file for you to analyze if there is an error?

Fernando's avatar Fernando  ( 2018-01-05 04:22:25 -0600 )edit

(Can you please add these images to your original question, rather as an answer?)

Julien Marrec's avatar Julien Marrec  ( 2018-01-05 04:24:15 -0600 )edit

@Fernando, yes you can send me the idf. My email address is in my user profile.

rraustad's avatar rraustad  ( 2018-01-05 07:45:36 -0600 )edit

I already sent an email for your address.

Fernando's avatar Fernando  ( 2018-01-06 06:47:35 -0600 )edit

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Asked: 2018-01-04 06:08:12 -0600

Seen: 783 times

Last updated: Jan 05 '18