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In the last 40 years, human consumption of earth natural resources has tripled. Climate change is one of the biggest challenges of our time. One of the major drivers is the building sector, and it is growing.
Because temperature is rising and, in the same time, living and working standards are getting higher in Europe, the demand for air conditioning in buildings is growing and the need for energy increasing.
An indirect green wall can help cooling down the building, with potential to save up to 40% of the needed cooling energy  and can also lower the temperature up to 1.2 ° C in the near-ground area and improve the micro climate.

This research aims to create a tool that optimizes the layout of indirect green walls according to the buildin geometry and the location. The tool is supposed to make green walls more common by reducing the amount of planning and making it part of the earliest stages of designing by including it in the Grasshopper environment. The optimisation aims a minimization of façade occupation and a maximisation of the cooling need reduction

The research focused on gathering basic information about effects and needs of indirect green walls. Indirect green walls help to cool down the building and its environment by sun radiation reduction through shading and by evapotranspiration.

The shading factor highly depends on the plants’ Leaf Area Index, LAI . It describes the leaf density of a plant.
In general, the higher the density, the better. Of course, the shading effect depends on the position of the sun and on the façade orientation.
Evatranspiration depends on the plant itself, but also on the climate. While a building in a warm and humid climate will benefit a lot of evatranspiration, the effec in a warm and dry climate is comparatively small.

With this information, a tool for optimized layouting of green walls is created. The optimization focus is here on an effective cooling of the building.

In this research, the focus is on a low complexity solution that gives a first feedback to designers that don’t have the needed background or resources to work through any of the complex workflows. This can help designers considering green walls from the beginning in the concept and can help optimizing the cooling effect. The focus is here to minimize the façade occupation and maximize the effect, so that a goo daylight supply is given.

The tool therefore needs to be as simple as possible, wit a minimum information input and a very clear feedback.

The needed information is geometry of the facade, the surrounding, location and basic climate data.

It is part of the visual programming environment Grasshopper for Rhino and is written in C# and Phyton
but also with usual Grasshopper components.

The full research paper and also the developed tool is available on request.