Model Mechanical Ventilation with Heat Recovery (MVHR) and room zones in residential flat

grasshopper honeybee-legacy
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1

Hi there,

I am building an energy model of a residential flat in GH + HB and I am currently stuck on 2 points:

  1. How can I model a Mechanical Ventilation with Heat Recovery (MVHR) system?
    Basically I want a fix air flow at outdoor air temperature entering the room with a % heat recovery.

  2. How do I assign specific zones to different rooms, e.g. kitchen, bedroom, etc.? I can only see ‘apartment’ in the Honeybee_ListZonePrograms.

Any help would be very much appreciated.

Thank you!

Antonietta

2

Hi @anto.ac,

  1. Are you talking about DOAS system with heat recovery? or DOAS without heating and cooling components?
  2. You can use small or large hotel as a reference for internal loads and schedules, and you can always override any settings by using your own values.
3

Hi Mingbo,

Thanks for this. I will use the hotel zones as a basis and then adjust the schedules and loads :wink:
Regarding the ventilation system, I don’t think the DOAS is what I am after. Basically the unit I would like to model does not have any heating or cooling coil, it’s just a fix volume fan-assisted system with heat recovery between supply and extract air flow. Something like this:
https://www.nuaire.co.uk/residential/heat-recovery-mvhr/mrxboxab-eco-lp2

I have used the natural ventilaiton component, assigned fan-assisted natural ventilation, but then I cannot specify the heat recovery… is there something I can do about this?

Thanks,
Antonietta

4

@anto.ac I probably would model a DOAS-ish system without heating and cooling coils, this has been suggested on Unmet: https://unmethours.com/question/12726/mechanical-ventilation-with-heat-recovery/

I quickly created an example file with MVHR system with 80% heat recovery.
Simple Model for MVHR test.gh (557.7 KB)

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image.png1908×854 148 KB

Please let me know if this makes sense to you.

1 Like
5

Hi Mingbo,
That’s great, thank you! I have installed Ironbug but my components look different from yours and some disappear when I open your file. What am I doing wrong? How can I fix it, please?

Capture
Capture.JPG1709×778 134 KB

6

@anto.ac it looks like you didn’t install the newest version.
Did you try to installed from https://github.com/MingboPeng/Ironbug/releases ?

7

I had installed the wrong version indeed. Thanks a lot!

8

Hi Mingbo,

I have added your MVHR component but it doesn’t seem to work properly. Would you be able to have a look at my model, please?

Thanks a lot,
Antonietta

Energy model_SIMPLE.gh (1.1 MB)

9

Hi @anto.ac
You just need to put the customized HVAC system to “ExportOpenStudio”:

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image.png1782×813 181 KB

You can also check same ironbug examples for general workflows on https://hydrashare.github.io/hydra/

10

HI @MingboPeng, related issue to this. If I use an Ideal Loads system and apply heat recovery on it, would the heat recovery be still on even in summer? is there a way to set up a summer bypass? or a profile for it?
Thank you!

11

Hello,

old message thread, but I will try to ask my question here to @MingboPeng :slight_smile:
I would like to have in my model a mechanical ventilation with Heat recovery (as you’ve shown, without heating and cooling coils) and a “2.PTHP | Residential” system.
I connected:

  • the “2.PTHP” to the “HBZones” input of the openstudio component;
  • the input “HBzones” of MVHR is the output of “2.PTHP” and the output of MVHR is connected to “HVAC systems” of the openstudio component.

Does this make sense to connect it that way?

Image:

image
image2980×1560 624 KB

Model:
MVHR_ladybug forum.gh (297.3 KB)

Thank you for your help!

12

Hi @mkdg,

You cannot use Honeybee’s template system with Ironbug system for the same zones, because Ironbug will remove all HVAC related settings before adding a new system to the model.

For all electric version: you can add PTHP system from Ironbug to your zones.

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image653×528 108 KB

1 Like
15

Hello @MingboPeng !
I have noticed that the solution you said in your last post that this would work only for “all electric version”. Is it possible to also add a PTAC component with MVHR, as shown below:

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image1887×1177 163 KB

I wonder if it’s correct, because I am surprised to see that a scenario with PTAC only consumes less gas for space heating (359 kWh/m2) than the scenario PTAC + MVHR (363 kWh/m2).

I also attached the gh. file
MVHR_ladybug forum.gh (305.4 KB)

16

Hi @MingboPeng
Thanks for the helpful post!

I’ve got two more questions related to this if you know the answer.

  1. I created my model from breps rooms to HBobj, in this case is there a way to connect to IB like you did (but from HBObj instead of HBZones) to generate MVHR results?

  2. The OBM I used are from HB-Energy (ver1.6.2), would that be compatible with HB-Legacy?

Thanks in advance for your help.

17

Hi @MingboPeng,

I have a question about this simple model for MVHR. How can I connect it with a heating and cooling system for example HeatPump?

Thank you

18

Hi @MingboPeng

In continuation to Mariafa’s question, I do we make a MVHR with peak lopping cooling?
Thanks.

19

Hi @Eva7 @Mariafa,

Have you tried to build a pototype sytem in OpenStudio Application? If yes, please share your sample osm file and I can help you with replicating it with Ironbug.

If not, could you please provide more details about the system what you are trying to build. From my understanding, you can totally use DOAS + Heat Recovery + almost any type of heating and cooling system for your system (MVHR+heating and cooling).

20

Hi @MingboPeng,

Thank you for your response.
I do not have much experience with ironbug. So it might be a simple thing but I am trying to replicate a MVHR with peak lop cooling. That would essentially provide heat recovery till say my outdoor temperatures are less than 24 and then provide a supply air temperature of 16 degree when outside air temperatures are more than 24.