Characterisation of Molecular Solar Thermal (MOST) Energy Storage Materials in Miniature Windows
Examensarbete för masterexamen
Finding and developing alternative ways of capturing and storing energy which lead us in the direction of a more sustainable society is one of today’s major challenges. One of these emerging methods is by using molecule solar thermal energy storage (MOST) systems. The principle of the system is a photo-switching process which occurs when the parent molecule is irradiated causing it to form a high energy isomer. As the isomer switches back to the original molecule, energy is released in the form of heat. These molecules can be integrated into different types of matrices such as solutions and films. In this Master’s thesis, the MOST-system are investigated by incorporating the MOST-molecules or photo-switches in thin polystyrene films and monitoring the absorbance of the photochromic materials as a function of film thickness when subjected to irradiation. The project is divided in to two parts; the first consisting of small scale tests of the films in lab. Specifically two molecules are investigated, a norbornadiene and an azobenzene. The photochromic materials are exposed to both LED light using a solar simulator and natural solar radiation for various amounts of time over a number of days and the absorbance is monitored to understand the behaviour of the molecules in films. The second part of the project consists of integrating the materials as windows on a larger scale in a model house and observing the effects of the indoor environment of the house by measuring temperature. The discoveries from the first part of the project show that the absorbance of the films generally decrease over time with increasing film thickness. When exposed to natural solar radiation, the norbornadiene molecule showed a significant level of degradation compared to the azobenzene. The azobenzene was therefore selected for further testing in the windows of the model house. The experiments from the outdoor setup demonstrated that it is highly likely that the windows containing the MOST-molecules have an affect on the heating of the indoor environment during the night. However, the differences were still small and requires further investigation with larger concentrations of the molecule.
Solar energy storage , Photochromic materials , Photoswitches , Norbornadiene , Azobenzene