Thermochrome Absorberbeschichtung

• Unité de recherche: OFEN
• Numéro de projet: 102016

Mots-clé (Allemand)

TP0072;F - Solarwärme u. Wärmespeicherung

Description succincte (Allemand)

-Vorstudie für thermochrome Absorberbeschichtung zur Reduktion der Stagnationstemperaturen von selektiv beschichteten Kollektoren.
-Thermochromie II - Advanced switchable selective absorber coatings for overheating protection of solar thermal collectors

Rapport final (Anglais)

The market of thermal solar collectors is increasing consequently and collectors need improvements to meet customers’ rising expectations. Durability of materials is a critical point as the collector lifetime should be at least 25 years. Overheating and the resulting stagnation of the collector is a common problem with solar thermal systems. During stagnation high temperatures lead to water evaporation (and glycol degradation above 160°C) and stresses in the collector with increasing pressure. A promising way to achieve active cooling of collectors without any mechanical device for pressure release or collector emptying is to produce a selective coating which is able to switch its optical properties at a critical temperature Tc. An optical switch allows changing the selective coating efficiency; the goal is to obtain a coating with a poor selectivity above Tc (decreasing of absorptance, increasing of emittance). Obtaining self-cooling collectors will allow increasing collector surfaces on facades and roofs in order to get high efficiency and hot water production during winter without inconvenient overheating during summer. Optical switching of materials can be obtained by many ways. Inorganic and organic thermochromic compounds, and organic thermotropic coatings are the main types of switching coatings that have been studied. A concept for absorptance switching of collectors with inorganic materials has also been studied.

Auftragnehmer/Contractant/Contraente/Contractor:


Autorschaft/Auteurs/Autori/Authors:
Huot,Grégory
Roecker,Christian
Schüler,Andreas

Documents annexés

• Evaluation of the Potential of Optical Switching Materials for Overheating Protection of Thermal Solar Collectors - Final report [PDF] 473 kB