Waterskater

Low-carbon building materials, such as earth-based and bio-based ones, often have an excellent ability to regulate indoor humidity levels. Due to their hygroscopic nature, they can buffer moisture from the indoor environment, absorbing it when humidity rises and releasing it when the air becomes drier. This moisture-buffering capacity can moderate indoor humidity levels, contributing to improve comfort and well-being while also reducing the energy demands of buildings. However, the extent of these benefits depends on factors such as building usage, occupancy, ventilation rates, and external climate conditions. Therefore, dynamic hygrothermal simulations are often necessary to quantify the benefits of these materials in specific design scenarios.

Commonly used energy simulation tools in the early design stages of architectural projects, such as the Grasshopper plugin Ladybug, do not account for moisture transfer phenomena in building materials. In contrast, advanced dynamic hygrothermal simulation tools like EnergyPlus, WUFI Plus, and HAMBASE can successfully account for moisture transfer but require specialised knowledge, making them challenging to use in the early design stages of architectural processes.

To address this gap, a new early-stage simulation tool - the Grasshopper plugin WaterSkater - has been developed at the Chair of Sustainable Construction of ETH Zurich. It integrates dynamic heat, air, and moisture calculations using the Grasshopper interface and leveraging the EnergyPlus engine, specifically using the ‘Combined Heat And Moisture Finite Element’ algorithm.

The plugin is designed to allow the users to assess the benefits of hygroscopic materials in regulating indoor relative humidity, enabling early-stage evaluations of potential improvements in comfort and reductions in energy demands. Currently, the plugin is undergoing final validation and is not yet available online.

To access the tool, please contact the developers, Magda Posani and externe Seite Yasmine Priore.