IronBug causing a slab ground temperature issue

[Yure]

I am modeling a simple single-family home, and I used Ironbug to specify my system’s COP etc. After using Ironbug, I started getting some loads that were not representative of the building type and location in Texas (I was getting WAY more heating than Cooling). We figured it was because the model was somehow not reading ground temperatures correctly, but this only happens when I connect Ironbug to the script. In other words, using a Heatpump in IronBug is not lending to realistic loads, but when I use Honeybee’s Heatpump it does.

I am sharing a couple of screenshots to illustrate. I wonder what I could be doing wrong. I would really like to be able to control systems size, fans, etc. and use Ironbug as this is a seed file.

This is the system that DOES seem to have more logical loads (AKA using HB Heatpump)

The system does not show realistic loads and has a problem with ground temperature:

More detail on the ground temperature/ slab error using Ironbug

Balance Chart - Heat Gain/stored Inquiry

Hi @Yure, I think I’ll need more context to understand what’s happening here. Adding the other load balance items (heating, cooling, etc) will help for context. Is your space/spaces conditioned? What does your geometry look like? What’s the U-value of you constructions? The window conduction seems to be behaving somewhat as expected, so I assume that your internal temperature is something reasonable. Looking at avg high and low temperature for Texas it seems in peak summer it’s between 25-…

[Yure]

@chris tagging you here just in case you have a quick response. I believe this is some sort of bug or conflict.

Hopefully you have some insights.

[MingboPeng]

Hi @Yure, I am not sure what happened without looking at how you built the system with Ironbug. But have you tried to use the new advanced template that I added recently in the new version? These systems matches all realistic parameters of the system from the Honeybee templates.

[Yure]

Hi @MingboPeng !

I was able to find the latest Sys04_SZHP_All_Elec script. I plugged it in and it is giving me the following error: 1. Solution exception:Airloop needs at least one fan!

I am modeling a single zone detached home. Any thoughts?

[Yure]

Hello @MingboPeng -

I was able to make the HVAC work, but I am still having the same issue with the slab. See pictures below.

I am not adding an image of the system because I did not change a thing from the ‘Sys04_SZHP_All_Elec’ that exists in IronBug.

Any ideas as of why this could be happening and how to fix it? This is throwing my results off and making my whole model non reliable.

Best,

[Yure]

Hello @MingboPeng!

I went ahead and simplified my file so I can share it here. To sum up: the issue is that, when I connect Ironbug Heatpump Systm4 (as suggested), the total heating load is higher than anticipated. I found out thanks for @charlie.brooker that this is due to ground temperature being set at 18C. After connecting a ground temperature in _add_string, the model is still showing a continue temperature of 18C. This is not happening when I use heatpump from Honeybee.

I am thinking Ironbug is disconnecting ground temperatures or something along those lines. Please let me know if this can be fixed in my end or yours.

Attached my model. it is a simple single fam house. I hope this helps.

2023.0118 - Reduced Iron Bug Issue.gh (700.0 KB)

[MingboPeng]

Thanks @Yure, attaching a sample file is really helpful for me to understand and debug your problem. I will look at it tomorrow.

[MingboPeng]

Hi @Yure,

You will need to connect the same “add_str” to “HB_Run OSM” component.