HVAC system _ IdealAirLoads _ Heat recovery?

grasshopper honeybee-legacy
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Hi everyone,

I am running my first Energy Modelling in OpenStudio. I have not specified the type of HVAC system. As a default, the HVAC system considered is Ideal Air Loads.

For this type of system, what are the default values for the following?

  • Heat Recovery type
  • Sensible Heat Recovery Effectiveness
  • Latent Heat Recovery Effectiveness

Thank you in advance.

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Hi @Lucia_Delilah

The safest way to find out what’s been used as default value in model is to go check the output idf file.

All Ideal Air loads related document for reference:
https://bigladdersoftware.com/epx/docs/9-2/input-output-reference/group-zone-forced-air-units.html#zonehvacidealloadsairsystem

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Hi @MingboPeng

Thank you for the reply and for sharing the document. I already had the chance to look at it. As far as I can understand, the default Heat recovery type is none. Therefore there is no heat recovery, right?

Thank you

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@Lucia_Delilah right, I don’t think you can set heat recovery for Ideal air loads in Honeybee. It should be none for no heat recovery. But if you want to have a full control of Ideal air loads, you can use Ironbug to edit the system.

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@MingboPeng thank you for the suggestion.
I am not familiar with Ironbug and I do not think I will get that level of details for now. I was just wondering if there was a way to set up a default value for the heat recovery. If not, can I still define both the sensible and latent heat recovery effectiveness through the Air Details component?
Also - In the document you shared earlier there are reported default values for these two elements. If so, why is the heat recovery none by default?

Thank you again

HR_IdealAirLoads
HR_IdealAirLoads797Ă—599 46.9 KB

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@Lucia_Delilah
AirDeails settings are mainly for setting up the real HVAC systems. You can try to put a value for recovery effectiveness here to see if it would be applied to ideal air loads. My guess is it won’t.

In terms default value, the document that I referenced is for EnergyPlus, but before all values passed to EnergyPlus, there are two more layers that between you and EnergyPlus, which are Honeybee, and OpenStudio.

Both Honeybee and OpenStudio have their own “default” values are coded within their own systems for whatever reason. These defaults might be the same, or “simplified”.

Settings in EnergyPlus are all things that you CAN do, but settings within Honeybee and OpenStudio are things that they (developers) WANT you to do.

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