Research on Thermochromic and PCM Doped Infrared Reflective Coatings
Pp. 83-103 (21)
Theoni Karlessi and Mattheos Santamouris
The present research investigates the development of thermochromic and
PCM doped infrared reflective coatings and the potential of their application on urban
structures in energy savings and improvement of the microclimate.
Thermochromic coatings were developed by using thermochromic pigments into an
appropriate binder system. The color-changing temperature was 30°C. The same binder
system was used for the production of highly reflective (cool) and common coatings, in
order to investigate and compare the thermal and optical characteristics of colormatched
thermochromic, cool and common coatings. The results demonstrated that
during the experimental period, surface temperatures of thermochromic samples were
lower than the temperatures of color-matched cool and common. Issues concerning the
photodegradationof thermochromic coatings are also discussed.
The performance of organic PCMs used as latent heat storage materials, when they are
incorporated in building coatings is also studied. Comparative testing proved that all
PCM doped infrared reflective coatings present lower surface temperatures than cool
and common coatings of the same color. Studying the daily temperature differences it
was noticed that peak temperature differences occur between PCM and common or cool
coatings from 7am-10am.These peak temperature differences are not noticed for
common and cool coatings. Moreover investigating the temperature gradient it was
shown that for this time period the values for the PCM coatings is much lower
compared to cool and common. Coatings containing PCMs store heat in a latent form
maintaining constant surface temperatures and discharge with a time delay.
Phase change materials, thermochromic pigments, optical and thermal
Group Building Environmental Studies, National and Kapodistrian University of Athens, Section. of Applied Physics, Physics Dept., Building of Physics 5,University Campus 157 84 Athens, Greece.