Re: [EnergyPlus_Support] exhsaust from conditioned space for cooling condenser

Hi Julien,

I mostly use E+ for the refrigeration system module, and for the air condensersÂ of some of the refrigeration systems there is the option to use an airÂ exhaust node (for Air Inlet Node Name), otherwise the default node (if left blank) for condensers inlet is the outside DB. As follows for instance:

Refrigeration:GasCooler:AirCooled,

Â Â RefrigGasCooler, Â Â Â Â !- Name

Â Â GasCoolerHRCurve, Â Â Â Â !- Rated Total Heat Rejection Rate Curve Name

Â Â Fixed, Â Â Â Â Â Â Â Â Â !- Gas Cooler Fan Speed Control Type

Â Â 8000.0, Â Â Â Â Â Â Â Â Â !- Rated Fan Power {W}

Â Â 0.2, Â Â Â Â Â Â Â Â Â Â !- Minimum Fan Air Flow Ratio {dimensionless}

Â Â 27.0, Â Â Â Â Â Â Â Â Â Â !- Transition Temperature {C}

Â Â 3.0, Â Â Â Â Â Â Â Â Â Â !- Transcritical Approach Temperature {DeltaC}

Â Â 10.0, Â Â Â Â Â Â Â Â Â Â !- Subcritical Temperature Difference {DeltaC}

Â Â 10.0, Â Â Â Â Â Â Â Â Â Â !- Minimum Condensing Temperature {C}

Â Â , Â Â Â Â Â Â Â Â Â Â Â Â !- Air Inlet Node Name

Â Â RefrigGasCooler; Â Â Â Â !- End-Use Subcategory

And you said use EMS; I am ok to do that, but which one is "exhaust air node of your airloopHVAC" for the ExampleFile I referred. The only ExampleFiles I saw where the "exhaust air node" is explicitly defined is for those with "AirflowNetwork". I never looked at the use of "AirflowNetwork" before, and also did not want to spend on this new application if it would easily be figured out with simpler simulations. Anyway thanks for your input.

I will do a further assessmentÂ if I need to spend more time on this versus the potential energy reclaim/benefit.

Regards,

On Tue, Jan 17, 2017 at 9:16 PM, Julien MARREC julien.marrec@xxxxxxxxx [EnergyPlus_Support] <EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:

Â

Hi,

I could be wrong but I don't think there's an option to do this right out of the box in E+ (meaning there isn't a field to add an exhaust air node at the condenser air inlet node but that's easy to check).

Otherwise you can do this with EnergyManagementSystem (EMS). The logic would likely be similar to this:
Put a sensor for temperature (and flow rate) at the exhaust air node of your airloopHVAC(s), and an actuator or the outdoor air node for the condenser inlet and overwrite its temperature via an EMS program. You'll likely need to do some calculation on the temperature if you think your exhaust airflow is lower than the condenser inlet airflow needed (in this case a sensor for the flow rate is needed too).

Hope that helps,
JulienÂ

EnvoyÃ© de mon iPhone

Le 16 janv. 2017 Ã 00:06, "tilek.aberra@xxxxxxxxx [EnergyPlus_Support]" <EnergyPlus_Support@yahoogroups.com> a Ã©critÂ :

Â

Hi,
How do I extractÂ the exhaustÂ air temperature and flow rate of an air conditioned building from anÂ Energyplus simulation?Â I was thinkingÂ to reclaim some of the cooling in the exhaust air for condenser cooling. Can someone guide me on this using one from the ExampleFiles, say "5ZoneAirCooled.idf" or share me their experience.

Regards,
Tilek
Â

Tilek Aberra,
12 Bainton Pl., Doonside,
Sydney, Australia
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