Hi!
I have a rather open question to the forum. Why is there no LCA-tool embedded in the Ladybug-package?
The reason I’m asking, is that I am given a trial lecture entitled " Digital design and fabrication: Challenges, Barriers, Opportunities in Design Practice and new Research Trajectories for the reduction of carbon footprints in buildings"
I’m not yet into this topic, but my PHD-topic is into parametric detailing and fabrication of timber structures. I’ve read about Ladybug tools several times, and have always assumed there was an implemented way of doing LCA using Ladybug.
From previous forum-posts, I have read that the main issue is that databases are not sufficiently open? Is that still the case? Or are there other barriers that prevents the building industry from having a proper tool for parametric LCA?
Hi @Johnhaddal,
If you happen to know publicly available resources on LCA information for materials, please share and we would be interested in creating workflows around it. This questions has been asked before and we remain interested in integrating LCA in Honeybee workflows.
Thanks for sharing @ncatunda, I assume that this tool only works with Swiss materials. I could find their code base on Github and I will look into this. We would ideally need material databases for the North American region to start something on this front.
Yes, it is based on Swiss standards. The data was centralized in the Ecoinvent project, as far as I know. If anyone is curious, here is the link https://www.ecoinvent.org/
A little bit about it:
“The material and energy balances for the large number of building materials come from various companies, associations and research institutes in Germany and abroad. They were harmonised as part of the ecoinvent project, a joint initiative of the ETH Domain and Swiss federal offices [2] and prepared in a userfriendly manner by KBOB, eco-bau and IPB [3].”
source: SIA 2032 - Swiss standard about grey energy
There is another database I know, but it is also European (Home - building-transparency.org). The materials on this one are classified as “Environmental Product Declarations (EPDs)”, which apparently is different from the method that Ecoinvent uses, but I honestly know too litlle to really discuss more about it.
this is awesome, I’m doing my thesis at the moment and I’m struggling to find a reliable source for LCA related building material data.
some problems I encountered:
changing the insulation thickness in the material example file won’t change the U-value for certain materials (e.g. Foam glass gravel (137.5 kg/m3) | 10.013)., only the GWP output - is it a missing thermal conductivity causing this (the last line was 0 from the KBOB Material component)? I guess the default setting in the material file was an unfortunate coincidence, the rest I’ve checked has a lambda assigned.
how is the U-value calculated? I assumed 1/sum(Ri), where Ri = sum(d_i/lambda_i) for the layers and 1/h_i + 1/h_e for the bounding surfaces, the latter being predetermined based on the Functionality input? I’ve checked the Github repository for Bombyx, but I’m struggling to read C# (I’m rather new to energy modelling and programming) to decode the whole property passing process.
I cannot figure out the order of these parameters:
at the component impact why are the two densities added? I assumed that component output would indicate properties to the component level, in this case rho_avg = d1/(d1+d2)*rho_1 + d2/(d1+d2)*rho_2?
I’m confused …also not familiar with the ecoinvent database (familiarity could mean I don’t have these questions…), and I only have a vague undertanding of LCA in general, I would be appreciate having some guidance where to look/what to read first to understand what Bombyx is actually doing!
Unfortunately I cannot help answering the questions. I also found the other day some weird U values, not sure if the component is putting another values in the middle or just a bug. Maybe you would want to send an email to bombyx@ibi.baug.ethz.ch. Hopefully someone there answer your questions
PS: please let me know if they do, cause I am also curious
This is a very interesting and timely discussion.
I believe the developer of cove tool (which I have not had the time to fully test yet) have integrated - not sure if via an API - the EC3 database
The EC3 tool is open source and good as a starting point, however it appears to be US-focused mainly, which is a bit of a limitation for someone based in EU/UK like myself.
Would it not be a matter of writing components that link to existing, open databases?
@ncatunda Thanks, I contacted them. If I get an update, I will keep you updated.
I also linked this thread and suggested that they reply here - we’ll see.
I got a fast reply from Saso, the developer of Bombyx:
First of all, thank you very much for trying out our LCA addon.
I am only one man working on Bombyx and demands are changing quite often, which results in delayed release of new version.
But we will be releasing a new version very soon, that will have a bit more included.
Inputs-Outputs:
The old version was pretty unclear I agree, that’s why we fixed a lot of issues in the new version by naming the corresponding inputs and outputs the same and adding additional outputs so users can check the data
New version will also include an example file, so users can see how everything works
U-Value:
We calculate u value 1/(Sum of all R-Value) where R = thickness/thermal conductivity
Old database lacks a lot of data that is true and this is fixed in the upcoming version
Other databases:
We are using data from KBOB and if Ecoinvent provides API and free data, we could include it in one of the next versions
Materials are stored in the database.
Starting points:
We are preparing tutorials for Github where we’ll add links to published papers on LCA
Again thank you for your interest in Bombyx and thank you for pointing out what needs more work, so that the addon can be more user friendly.
New version is coming very soon and it will be published on food4rhino.
It seems, that lot of the above mentioned issues will be solved in a new release coming soon.
I came here to add another 2 cents for the topic. It is about the difference in between the Swiss databases and the EDPs (Environmental Product Declarations). Please see image attached. For more information please go to the paper called:
“Integrated BIM-Based LCA for the Entire BuildingProcess Using an Existing Structure for CostEstimation in the Swiss Context”. Authors: Anita Naneva, Marcella Bonanomi, Alexander Hollberg, Guillaume Habert and Daniel Hall.
I would like to express my support for LBT to develop an LCA extension to the existing tools suite, and think it would be very well utilised. However the thread below prompted me to consider how this could be made to work practically. Embodied carbon data (A1-A3) for materials will vary based on the region that project is in (and where the materials are sourced). The EC3 seems a good North American database, and similarly in the UK there is the ICE database - also freely available.
Perhaps the selection for loading LCA data could work in a similar way to how attaching weather data works in LB/HB? Select a region, and the most relevant LCA data is added into the file?
…also not familiar with the ecoinvent database (familiarity could mean I don’t have these questions…), and I only have a vague undertanding of LCA in general, I would be appreciate having some guidance where to look/what to read first to understand what Bombyx is actually doing! 
