Cross-Platform Application for High Resolution Thermal Comfort Mapping from Energy Models: Phase I Final Report
- Ladybug Tools LLC
Many building design professionals assume that, as long as there is an heating/cooling system that is sized to meet a thermostat temperature at a single point in the room, occupants throughout the space will be comfortable but this assumption is far from reality. Within a given space that is exposed to an exterior facade, temperatures can vary widely, increasing the risk of occupant discomfort. This is an issue in its own right but perhaps the larger missed opportunity is that many of the strategies that would mitigate these uncomfortable conditions, such as shading, better-insulated windows, and lower glazing ratios, would also result in savings of heating and cooling energy. Ladybug Tool LLC seeks to address these issues by enabling building industry professionals to simulate detailed thermal maps of their building designs. This report describes the current findings and the ultimate result of research done during Phase I of a U.S. Department of Energy SBIR grant. The primary objective of Phase I was to develop a cross-platform thermal mapping software application that takes an energy model as input and can produce annual hourly thermal comfort results across the model. Importantly, the application was to be executable on all major operating systems without the need for CAD software. By making such capabilities cross-platform, not only could other software developers make use of such thermal mapping capabilities in their own applications but it also paves the way for inclusion of thermal maps into building industry standards, like the ASHRAE-55 thermal comfort standard. During Phase I, a cross-platform, open source application for thermal comfort mapping was successfully designed, built and distributed. Distribution channels include the Python Package Manager (PyPI), where other software developers can currently access the application in order to enhance their own software. Distribution is also done through the most recent Ladybug Tools CAD plugin for Grasshopper, which is the expected means by which practitioners will currently access the thermal mapping capabilities. Over the course of the application’s development, several notable improvements were made. Most significant among these improvements was the use of the Radiance simulation engine to account for the effects of direct and reflected sun energy shining on occupants and causing them to feel warmer than they would otherwise. This was accomplished by creating a new file type (aka. file schema), which helped coordinate the assumptions of the input energy model with the physics-based rendering process of the Radiance engine. The result is a thermal mapping application with an unprecedented level of accuracy in regards to the computation of Mean Radiant Temperature (MRT), which can be used to inform building designers of the impact that their decisions have on occupant thermal comfort.
- Research Organization:
- Ladybug Tools LLC
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- SC0019848
- OSTI ID:
- 1773148
- Type / Phase:
- SBIR (Phase I)
- Report Number(s):
- DOE-LBT-0019848
- Country of Publication:
- United States
- Language:
- English
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