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Designbuilder, no external ventilation output data, SHVAC Heat Recovery not working properly

asked 2024-09-06 05:00:16 -0500

AadriaanW's avatar

I want to compare the Heating Design sizing output with the yearly simulation output (Heat Balance + Internal Gains) to see the effect of building mass, use of the building, sunshine and other internal loads on what the size of the equipment should be, compared to the static Heating Design sizing simulation.

However, there are several things not going well. Both in Simple HVAC and Detailed HVAC I do not see Vent External as an output from my simulation view. I have added 2 screenshots below, 1 from Heating Design and 1 from the custom Heat Balance output I made in DB. It seems to me that there is ventilation going on since I can see Heat Recovery in the AHU Heat Recovery Output, so there is some ventilation going on, but it is simply not showing as an energy output.

When I use Simple HVAC I do not see any difference in turning heat recovery on or off, the required heating stays the same. When I use Detailed HVAC I do see an expected impact, but I still do not see the external ventilation as an energy output as I do when I use Heating Design.

When I use Heating Design calculation I do see the effect of different ventilation amounts and turning heat recovery on or off, so there I get what I want, just not in the yearly simulation.

Which settings am I not using correctly? How can I get the heat recovery in Simple HVAC work and in both Simple and Detailed HVAC get the External Vent energy output variable?

C:\fakepath\Heatbalance without ventilation (simulation).png

C:\fakepath\Heating design with ventilation output.png

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answered 2024-09-26 05:01:08 -0500

Tokarzewski's avatar

You can include or exclude heat recovery in simple HVAC by using one checkbox under the heating header on the HVAC tab. It is called "Exclude heat recovery from zone heating sizing". It is described at https://designbuilder.co.uk/helpv7.3/...

You won't see a heat recovery output variable on the heating design. You should see the difference in the External Vent results when the above setting is selected or not.

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answered 2024-09-12 02:41:35 -0500

PmP's avatar

I can't say about the heat recovery not working for simple HVAC, the .idf is needed to see what is wrong with it, if anything.

About getting the external vent "energy output" when I need extra results from a DB simulation exported to energy plus I use this method of adding results in a script. It is very easy to do: https://designbuilder.co.uk/helpv7.0/...

You need to know in advance the name of the output variable you want. For example for simple HVAC it might be zone ideal loads supply air total heating rate and for detailed HVAC zone air system sensible heating rate.

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Asked: 2024-09-06 05:00:16 -0500

Seen: 328 times

Last updated: Sep 26