Outdoor Comfort Analysis using Rhino + Grasshopper Software

Updated: Apr 27

Words by Khim Bok

Simulations by: Bjorn Bull Hansen & Austin Lim

In many developments that we have either been personally involved in or had the chance to visit and experience in Malaysia, we’ve generally found that comfort and year-round useability of the outdoor spaces have not been given too much thought and planning. The design of many of these outdoor spaces tends towards complimenting the aesthetics of building and architecture design language, and not specifically designed for attracting more usage. Yet, we see examples of buildings, particularly retail and food & beverage type developments that are particularly successful because the outdoor spaces are attractive and comfortable. This just shows how important it is to design these outdoor spaces well for thermal comfort.

Living in Malaysia, we know that our biggest problem is the heat and humidity. This coupled with the lack of consistent breeze means that being outdoors can get uncomfortable very quickly. The main source of heat we experience is from the direct heat of the sun’s rays, indirect heat from warm surfaces nearby (e.g. feeling the heat radiating from nearby cars in a traffic jam), and the warm air.

Image 1: Sun Path diagram for Kuala Lumpur, Malaysia. The Sun path shows the position

of the sun at different times of day throughout the year. Sun path differs for depending

on the location relative to the equator. Understanding the movement and position of the

sun is possibly the most fundamental step in good design for outdoor spaces. (Sun path

diagram source: www.gaisma.com)

Short of installing an air conditioning system in outdoor spaces, which would be impractical for most instances since the operating cost would make it non viable, it would not be possible to change the air temperature. However, we can certainly do something about reducing direct heat from the sun and nearby warm surfaces.

In this write-up, we present a brief idea of how we utilized Rhinoceros 3D with Ladybug and Grasshopper plug-ins to model and predict outdoor thermal comfort conditions. The performance metrics that were modeled were Solar Radiation exposure, Solar Adjusted Mean Radiant Temperature and UTCI (Universal Thermal Climate Index).

The Solar Radiation exposure study provided us a quick review of how exposed the outdoor spaces would be to the sun’s rays throughout the day and year. As the sun’s position shifts throughout the year, even spaces below a canopy can be exposed to direct sunlight at some time of the year.