the new generation of scalable urban HEat isLand mitigatIOn by means of adaptive photoluminescent radiative cooling Skins

Introduction

From their early origins, urbanization has produced both benefits and penalties due to the generated anthropogenic stress. Documented overheating, such as the urban heat island (UHI) effect, compromises human wellbeing in cities, where 60% of the world population lives and is exposed to the related health risks and vulnerabilities.

Urgent Need for Solutions

An urgent solution is much needed here and now, since classic passive cooling techniques have shown to slowly mitigate UHI. A disruptive improvement must be dedicated to eradicating the problem by conducting groundbreaking multidimensional and multidisciplinary research.

Motivation of HELIOS

That is the key motivation of HELIOS, which aims at holistically developing the resilient urban skin of the future. This skin will take advantage of the combination of:

1. Successful radiative cooling in the atmospheric window (8-13 µm)
2. High solar reflectance integrated for the first time to photoluminescence in the short wave (0.25-2.8 µm) thanks to the breakthrough lead-free halide perovskites.

Development of Novel Structures

HELIOS will develop novel radiative cooling structures into temperature-responsive carriers (e.g., phase change-oxides, thermonastic shape-memory alloys) and albedo adaptive photoluminescent finishing. The twofold purpose of this development is to:

• Tailor radiative supercooling performance enough to minimize winter penalties.
• Provide the desired color finishing, finally allowing the sustainable upscaling of this research frontier.

Rethinking Building Physics

This approach would radically change the building physics paradigm, with the ambition of rethinking the built environment into a fully dynamic resilience, as only Nature can do. HELIOS will indeed analytically and experimentally identify the thermal-radiative physics of such skin, assessing its performance for indoor-outdoor human comfort and energy efficiency.

Tailoring and Optimization

HELIOS bio-inspired radiative and photoluminescent skin will be tailored and optimized for each dynamic boundary, as demonstrated through a disruptive building physics experimentally validated balance and urban canopy model worldwide.