Passive Cooling Against the (Night) Sky

  • Ron Zevenhoven Abo Akademi University, Turku Finland
  • Martin Falt Abo Akademi University, Turku Finland


This paper summarises R&D work that evolved towards the design of a smart skylight (roof window) aiming at keepingits inside compartment at a lower temperature than the surroundings. A skylight that gives maximum cooling (summer) or insulating (winter) performance is being optimised at Åbo Akademi University for conditions in (northern) Europe. As passive cooling through long-wave (LW) thermal radiation must counteract incoming short-wave (SW) thermal radiation, a drawback to that region is the length of daytime during summer. For equatorial locations like Kenya the use of a passive cooling skylight would benefit from the more constant duration of night-time and temperature. Depending on location for application, a two- or morewindowed skylight must be designed. Results presented include the modelling of skylight windows using a four-band thermal radiation model and Comsol Multiphysics software for simulation. Several cases show that very significant increases in (passive) cooling heat output can be achieved.
May 8, 2014
How to Cite
ZEVENHOVEN, Ron; FALT, Martin. Passive Cooling Against the (Night) Sky. JOURNAL OF SUSTAINABLE RESEARCH IN ENGINEERING, [S.l.], v. 1, n. 1, may 2014. ISSN 2409-1243. Available at: <>. Date accessed: 20 june 2018.


Thermal radiation; Radiative cooling; Sky