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Updated: Jul 19, 2025

Experimental System of Solar Adsorption Refrigeration with Concentrated Collector
Published on: October 18, 2017
Temperature-adaptive rooftop covering with synergetic modulation of solar and thermal radiation for maximal energy
Jiale Chai1, Jianheng Chen2, Zhanxiao Kang1
1School of Fashion and Textiles, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China.
Abstract:
The energy consumption for maintaining desired indoor temperature accounts for 20% of primary energy use worldwide. Passive rooftop modulation of solar/thermal radiation without external energy input has a great potential in building energy saving. However, existing passive rooftop modulation techniques failed to simultaneously modulate solar/thermal radiation in response to rooftop surface temperature which is closely related to the building thermal loads, leading to limited or even counter-productive overall energy saving. Here, we report the development of a surface temperature-adaptive rooftop covering with synergetic solar and thermal modulations. The covering, made of a scalable metalized polyethylene film, demonstrated excellent solar absorptance modulation (72.5%) and thermal emissivity modulation (79%) in response to its temperature change from 22°C (indoor heating setpoint) to 25°C (indoor cooling setpoint), and vice versa. Building energy simulations demonstrate that the proposed rooftop covering can achieve all-season energy savings across all climate regions.
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