Optimerade material för optiska komponenter i koncentrerande solfångare
The energy consumption continues to increase as the use of electronics and energy consuming equipment increases. The use of fossil fuels has to be phased out for this to be sustainable in the long run while the use of renewable energy continues to increase. A renewable energy source is solar energy but the production of heat and electricity are today very expensive compared to other energy sources and an important task for the solar energy market to grow is therefore to minimize the production cost of the solar collectors while increasing its efficiency to produce heat and/or electricity. One way to convert solar energy into heat is by using solar collectors and electricity can be produced by utilizing the produced heat, or by applying solar cells.This thesis aims to recommend a reflective material for the next generation solar collectors from Absolicon and to recommend a commercially available coating for the receiver tube of the solar collector. A market study has been carried out to investigate the cost-related aspects along with the optical and durable aspects for the optical material of the solar collector. Experimental evaluations have been performed to ensure that the optical materials meet the requirements that the supplier promises. The optical properties have been evaluated with advanced measuring equipment at the Ångströmlaboratoriet at Uppsala University and with an infrared camera. The measured values from the infrared camera were in turn used to theoretically calculate the thermal losses of the receiver tubes. To investigate the materials durability the materials were subjected to different climates in a climate chamber and all the tests that has been conducted in this thesis have been carried out both before and after the climate chamber simulation to investigate the materials optical and physical durability. An important aspect of the laminated films is that they should have good adhesive properties even when subjected to high temperatures and high humidity and a method to evaluate this has been developed.The result of the thesis shows that aluminum reflectors obtain the best optical results for concentrated solar collectors, but since aluminum is not suitable for the Absolicon solar collector TC160 the recommended reflector material is SF2, which showed good optical, adherent and durable properties which is desirable for a good solar collector and a total reflectance of 92.4 % was obtained. The material that is recommended as a receiver tube is R2 with a measured absorptance of 95.9 %, an emissivity of 17.7 % and the thermal energy loss was calculated to 1055 W. R2 is durable in high humidity and temperatures of 85°C for over 300 hours without the optical characteristics deteriorated. Based on the recommended materials, the next generation solar collectors from Absolicon obtained a theoretical calculated optical efficiency of 76 %.