A simple real time LCA model with visual feedback



This article demonstrates a parametric LCA model designed to support the early design stage. The model utilizes a method to calculate 1) Global Warming Potential (GWP) of building materials in the construction stage, 2) it utilizes hourly simulations of energy consumption to evaluate the use stage, and 3) a simple method to evaluate the end-of-life stage. The model outputs the results in various visual ways to demonstrate the concept of integrated dynamic models with LCA focus.

This model was first build as part of a student project called: Sustainability as design support: Implementing life cycle knowledge in the early design stage using an integrated dynamic model by Aleksander Probst Otovic, 25 June, 2015.

This article is meant as a “HOW-TO”-showcase. The method is proof of concept and so is the used data. The model is open source and may be used by anyone for any purpose. The model makes use of various tools and to use the model please follow the install instructions as written below

An integrated dynamic LCA model

The integrated dynamic model is situated between the design tool Rhino, the Visual programming language Grasshopper and the two calculation tools EnergyPlus (energy consumption) and Excel (LCA database).

Software requirements

Rhino 5.0
gHowl (excel-plugin)
Ladybug+Honeybee (EnergyPlus - plugin)
LCA-tool (Rhino+grasshopper+database-files shown to this article)

How it works

The first thing to do when using this tool is to point to a database – a source of data in which the model will take find its materiel inputs.

Step 1) Open the rhino-file, then the grasshopper-file. Copy & paste the directory and filename into the yellow box.

refer to a LCA database

Step 2) Modify the layers of each referenced surface (Srf). For instance chose bricks (item selector) as the outer layer and thickness of 0.23 m (slider). Any number of layers are allowed, as long as a layer have a material and a thickness. You can also copy & paste the entire wall setup to create a second wall type, just remember to input a unique index for the new construction. Any type of surface (planar, single curved or double curved surface) can be used as reference surface.

Chose surfaces and materials

Step 3) Turn on preview of “relative CO2 impact” (right click the component on the box icon). This shows the relative construction impact of the surfaces in the 3d-view. If any layers or thicknesses are altered you may see a live update of the relative CO2 impact. To change the default settings (colors, range [0-200 average GWP/m2] double-click the module and edit the corresponding nodes.

Visualize the impact in 3d

Visualized impact in 3d

Step 4) Modify the Use conditions, number of years the building is being used and sources of energy.

Use stage conditions

Step 5) Modify and chose End of life conditions, here two options are showed, landfill or reuse. Other conditions may be added in the database. Simply open the database add new data, save it and press F5 (recompute) in the Grasshopper interface.

End of life conditions

Step 6) Chose location, orientation of the building (0 is up, input 0-360 measured clock wise), Zoneprogram and Run simulation by double clicking on the False button. A hourly energy simulation will for about 20 seconds.

Set up basic simulation parameters

Step 7) Turn on the preview of the column graph (right click the component on the box icon). And set the Rhino preview to top view (lower right corner). This will display all the CO2 impacts in one graph. If any conditions is changed, the preview will update.

See dynamic preview of the overall Life Cycle Analysis

Final remarks

This article shows how to input data from a simple database made in excel into an integrated dynamic model which calculates the three stages of a building life cycle; construction, use and end of life. The article can be read as a tutorial or a show case of a very generic building case representing a typical office building. The show case does not represent detailed energy consumption during the use stage, as it assumes a single zone. In real use, more nuanced assumptions should be made for the energy simulations. Also the database supplied with the example are a proof of concept, do not expect the data to be valid. That said, you may write your own data and modify any parts of the model the way you prefer, as this model is open sourced and licensed under GNU General Public License .

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