Dear Group,
Renewable energy can be generated whenever heat flows from a hotter to a colder body. One such flow is from the warm surface of Earth to cold outer space, via infrared thermal radiation. Physicists at the Harvard School of Engineering and Applied Sciences envision a device that would harvest energy from Earth’s infrared emissions into outer space. Heated by the sun, our planet is warm compared to the frigid vacuum beyond. Thanks to recent technological advances, the researchers say, that heat imbalance could soon be transformed into direct-current (DC) power, taking advantage of a vast and untapped energy source. An emissive energy harvester (EEH) is a device that can generate energy from emitting thermal radiation* into the clear sky. * This new paper pubished in PNAS http://www.pnas.org/content/early/2014/02/26/1402036111.short. <http://www.pnas.org/content/early/2014/02/26/1402036111.short>BYRNES, Steven J., BLANCHARD, Romain, et CAPASSO, Federico. Harvesting renewable energy from Earth’s mid-infrared emissions. *Proceedings of the National Academy of Sciences*, 2014, p. 201402036. This technology and several others are also proposed in the following open access paper http://dx.doi.org/10.1016/j.rser.2013.12.032 by Ming, T., de_Richter, R., Liu, W., & Caillol, S. (2014). Fighting global warming by climate engineering: Is the Earth radiation management and the solar radiation management any option for fighting climate change?. *Renewable and Sustainable Energy Reviews*, *31*, 792-834. Regards Renaud Le samedi 25 janvier 2014 00:18:52 UTC+1, R Kiesgen de_Richter a écrit : Dear All, > > In SRM strategies, high-albedo surfaces are proposed to reduce solar heat > gains by reflecting an increased amount of solar energy. At ground level > the “cool roofs” and surface albedo change strategies very well described > by Alvia Gaskill (a former very important contributor to this group) seemed > sometime ago very promising. > > A very complementary technique to cool the Earth could be a strategy using > night sky cooling surfaces that can pump heat away by radiative cooling to > the atmosphere and get rid of the heat directly into outer space. The > longwave energy is removed directly by transmission through the atmospheric > window. > > When protected from wind, by clear sky and dry weather, heat transfer from > ground surface by IR radiation is much faster than air convection, so a net > cooling of the ground can occur resulting in well above air temperatures. > > This can be used to store at night, cold water for the daily use of > cooling buildings: > > http://www.fsec.ucf.edu/en/publications/pdf/fsec-cr-1771-08.pdf (short > version), > > http://www.fsec.ucf.edu/en/Publications/pdf/FSEC-CR-1882-11.pdf (long > version) > > Parker, D. S., Sherwin, J. R., Hermelink, A. H., & Center, F. S. E. > (2008). NightCool: A Nocturnal Radiation Cooling Concept. *2008 ACEEE > Summer Study on Energy Efficiency in Buildings*, 209-222. > > Don't you think that large scale development of similar technologies for > night time can be quite complementary to the daytime “cool roofs, cool > paints, cool coatings, cool pavements, cool roads…” strategies? > > > > In the Earth radiation budget diagram showing incoming solar radiation and > earth outgoing IR radiation, can this type of heat transfer be assimilated > to an increase of the “atmospheric window” pathway? > -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/geoengineering. For more options, visit https://groups.google.com/d/optout.
