Honeybee energy: Conditioned space inside an unconditioned space (greenhouse)

Hi everyone,

I am currently trying to simulate the effect of a greenhouse kind of construction on the energy use of an apartment unit which is located inside of it (the greenhouse is not actively temperated).

I managed to simulate the conditions inside the greenhouse (air temperature, energy balance), but now I would like to take these results as a starting point for an energy simulation of the apartment. I am struggling now to set it up and I was hoping someone has some input on that.
I tried a few things and ran into the following problems/questions:

  • In the HB_ExportToOpenStudio component, the only “climate input” is the epw-file, right? Is there a way to set “custom conditions”?
  • I tried settting up the (nested) zones inside each other: Does HB detect that the one is inside the other and account for that in the simulation? The HB_SolveAdjacancies component doesn’t seem to work, since the zones are not touching.
  • Set up zones where one is conditioned and one is not: The energy simulation is running for both zones, whereas I only want it to be run for the conditioned one, but taking into account the passive effects of the unconditioned one.

Here is a simplified model of my last attempt: Test_GreenhouseEnergy.gh (704.4 KB)

Looking forward to any kind of input, thanks ahead!
Cheers, Lukas

Hi @lukasl,

The problem comes with your geometry. One thing that is not allowed in Energy plus is to put rooms in rooms.
afbeelding

You can make a work arround by splitting the green house into different zones and define the imagenary walls as airwalls. In that case you should use the new Honeybee and not the legacy version. In the legacy version radiation is not passing through airwalls. An other option would be to attach the appartment to the ground with a column. (this is the most simple way) You have to put solar distribution of energySimPAR to 2 or 3 otherwise the simulation will not run because the room is not convex.

Test_GreenhouseEnergy.gh (433.2 KB)

Hi @Erikbeeren,
Thanks for your help!

Regarding your suggestions, the first one would hardly work I think since the actual geometry is a bit more complex. The greenhouse is bigger and there are more apartment boxes on different heights, so there would be a very large number of zones.

The one with the column would work, I also managed to set different states of conditioning for the different zones. I am still wondering how to exclude the not-conditioned zones from the results, but include them in the simulation (don’t know if that’s even possible). Because now for example the solar gains in the greenhouse are included in the energy balance, but I only wanna see the energy balance for the apartment. And then in the next step run the simulation without the greenhouse to see the difference.

I don’t know if it is possible, but in my mind the easiest solution would be to run the simulation for the greenhouse only, take the results and feed them into another simulations for the apartments only.

Update:

I found these posts on how to modify EPW files (How to modify EPW weather file and generate a new one? and Hydra Viewer). I followed the idea of running two consecutive simulations, where the second one uses the results of the first one. However, I get results for space heating between 200 - 7000 kWh/m2 without really changing a lot in the simulation (changes were adjusting internal loads a bit up and down). The funny thing is that if I restart Rhino and Grasshopper the results often reset to a more reasonable level.
But when looking at the surface energy flow then there is not no much lost through the walls and roof:

Also, the energy balance for the boxes looks wrong:

Is that related to me modifying the EPW and “messing it up”? Why is “storage” so big? I don’t have a lot of thermal mass in the construction here.

GreenhouseEnergy.gh (243.8 KB)

Hi @lukasl,

Sorry I did not reacted earlier. You can exclude the values from the simulation. Every result has an header which tells about which room the results belong to. So you can easily filter them out. I have put it into your gh script.


Test_GreenhouseEnergy.gh (978.5 KB)