Unforeseen challenges of common passive cooling strategies and how to solve them

With temperatures reaching record-breaking highs across the world this summer, many communities are looking for ways to beat the heat without increasing energy use or emissions. Passive cooling is an essential tool to accomplish both of these goals, but must be deployed thoughtfully to avoid some common pitfalls.

Possible passive cooling side effects

Structural challenges for retrofitting

Improving airflow by changing a building’s design or layout often requires significant structural changes. Unfortunately, this means that simple retrofitting options are quite limited, and extensive renovations might be necessary to achieve the desired improvements in air circulation. This can be both costly and logistically challenging, especially for older buildings.

Altered microclimates

Green roofs and walls are excellent for cooling buildings naturally, but they can also change local humidity levels and wind patterns. This shift can create pockets of increased humidity that affect nearby areas. A study in Urban Climate found that green roofs could boost local humidity by 5-10%, which isn’t always desirable for the surrounding environment.

Water demand for green infrastructure

Planting trees and other vegetation as part of passive cooling solutions requires a substantial amount of water to maintain them. In arid and desert regions, where water is scarce, this can pose a significant challenge. Ensuring the sustainability of green infrastructure in such areas requires careful planning and the implementation of water-efficient irrigation systems.

Mitigation strategies

Computational fluid dynamics (CFD) modeling

Advanced CFD modeling can predict and optimize the impact of passive cooling on local microclimates. CFD modeling can simulate multiple design scenarios to identify potential hot spots and humidity pockets before construction begins. This proactive approach allows for adjustments in design to mitigate negative side effects, ensuring that the final implementation achieves the desired cooling effects without unintended consequences.

Community Planning and Design

Addressing heat dispersion at a community level can also mitigate adverse effects. Strategic urban planning, such as creating green corridors, can help distribute heat more evenly across urban areas. Additionally, designing buildings to work in harmony with their surroundings, rather than in isolation, ensures that passive cooling measures contribute positively to the broader urban climate.

Water-Efficient Irrigation for Green Infrastructure

To address the water demands of green infrastructure in arid regions, implementing water-efficient irrigation systems is essential. Techniques such as drip irrigation, rainwater harvesting, and the use of drought-resistant plant species can help maintain green spaces without excessive water use.

Passive cooling uses natural processes to keep buildings, structures and people cool. With careful planning using modern technologies, many of the negative effects of high temperatures can be mitigated with these simple tools — especially in urban areas — without increasing reliance on the systems that contribute to global warming.