Abstract
Efficient passive radiative cooling of buildings requires an unimpeded view of the sky. However, vertical facades of buildings mostly see terrestrial features that become broadband-radiative heat sources in the summer and heat sinks in the winter. The resulting summertime terrestrial heat gain by buildings negates or overwhelms their narrowband longwave infrared (LWIR) radiative cooling to space, while the wintertime terrestrial heat loss causes overcooling. We show that selective LWIR emitters on vertical building facades can exploit the differential transmittance of the atmosphere toward the sky and between terrestrial objects to achieve higher summertime cooling and wintertime heating than conventionally used broadband emitters. The impact of this novel and passive thermoregulation is comparable to that of painting dark roofs white and is achievable with both novel and commonplace materials. Our findings represent new and remarkable opportunities for materials design and untapped thermoregulation of entities ranging from buildings to human bodies.
| Original language | English |
|---|---|
| Article number | 102065 |
| Journal | Cell Reports Physical Science |
| Volume | 5 |
| Issue number | 7 |
| DOIs | |
| State | Published - Jul 17 2024 |
Funding
J.M. thanks Prof. David Sailor of Arizona State University for providing and elucidating the raw data for Baniassadi et al.38; Dr. Tiphaine Galy and Prof. Laurent Pilon of the University of California, Los Angeles, for their assistance with preliminary measurements; and Prof. Sir Keith Burnett, Prof. Adam Overvig, and Dr. Kamal Krishna Mandal for helpful discussions. J.M. was supported by Schmidt Science Fellows, in partnership with the Rhodes Trust. A.P.R. acknowledges support from the Alfred P. Sloan Foundation and by the National Science Foundation under grant ECCS-2146577. J.B. was supported by a National Science Foundation Graduate Research Fellowship under grants DGE-1650605 and DGE-2034835. J.M. originated the concept and explored materials and optical mechanisms for selective LWIR emitters. A.P.R. supervised the study. J.M. and A.P.R. designed the experiments. J.M. S.M. and A.R. performed thermography, pyrgeometry, and image processing. J.B. prepared samples for experiments. J.M. and J.B. performed the outdoor experiments. J.M. performed the spectroscopy. J.A. and J.M. performed the building energy calculations. J.M. A.P.R. and S.M. wrote the manuscript. The concept detailed in this paper was first publicly disclosed on arXiv on June 21, 2020, and expanded in subsequent updates until May 7, 2021. A provisional patent application (WO/2021/087128) has been filed related to this article. J.M. thanks Prof. David Sailor of Arizona State University for providing and elucidating the raw data for Baniassadi et al. 39 ; Dr. Tiphaine Galy and Prof. Laurent Pilon of the University of California, Los Angeles, for their assistance with preliminary measurements; and Prof. Sir Keith Burnett, Prof. Adam Overvig, and Dr. Kamal Krishna Mandal for helpful discussions. J.M. was supported by Schmidt Science Fellows , in partnership with the Rhodes Trust. A.P.R. acknowledges support from the Alfred P. Sloan Foundation . J.B. was supported by a National Science Foundation Graduate Research Fellowship under grants DGE-1650605 and DGE-2034835 .
| Funders | Funder number |
|---|---|
| Alfred P. Sloan Foundation | |
| Schmidt Science Fellows | |
| National Science Foundation | ECCS-2146577, WO/2021/087128, DGE-2034835, DGE-1650605 |
| National Science Foundation |
Keywords
- broadband emitters
- building energy efficiency
- differential atmospheric transmission
- passive radiative thermoregulation
- radiative cooling
- selective longwave infrared emitters
- textiles
- thermal photonics
- walls
- windows
