Charging of a heat storage coupled with a low-cost small-scale solar parabolic trough for cooking purposes

• Published in: Solar energy 2013-09, Vol.95, p.144-154
• Main Authors: Mussard, Maxime, Nydal, Ole Jørgen
• Format: Article
• Language: English
• Subjects: Absorber; Applied sciences; Cooking; Energy; Energy. Thermal use of fuels; Equipments, installations and applications; Exact sciences and technology; Heat; Heat storage; Miscellaneous; Natural energy; Solar collectors; Solar cooking; Solar energy; Solar thermal; Solar thermal conversion; Temperature effects; Thermosyphon; Transport and storage of energy
• ISSN: 0038-092X; 1471-1257
• DOI: 10.1016/j.solener.2013.06.013

•An experimental comparison between two absorbers for charging a heat storage is done.•Both absorbers are coupled with a small-scale low cost solar parabolic trough.•The objective is to store heat above 200°C for cooking and frying purposes.•A simulation model is made to complete the experiments. Two charging experiments of a solar heat storage are presented. The heat storage is coupled with a self-circulating solar parabolic trough filled with thermal oil (Duratherm 630). The absorber tube is not insulated in the first test, and insulated with a glass tube during the second test (the air layer insulating the absorber is 7mm thick, enclosed between two glass cylinders). An electronic system tracks the sun during the experiments. The storage is mainly oil-based but contains a significant part of nitrate salts in order to store energy with latent heat (melting temperatures: 210–220°C). The salts are contained in eight aluminum cylinders. The cylinders are connected to a top plate and the assembly is immersed into a container where the oil circulates. The objective is to store heat at high temperatures for cooking purposes (boiling water and frying). The results show that at low temperatures, the absorber without insulation is much more effective. But when the storage temperature approaches 200°C, the glass tube becomes an advantage and a necessity for the further heat collection at higher temperatures. Above 200°C, it becomes difficult to collect without insulation around the receiver.