Thermosyphon Solar Hot Water Heater Development
Abstract
Thermosyphon solar hot water systems have been a subject to R&D activities of the CENTRE OF EXCELLENCE FOR RENEWABLE ENERGY RESEARCH at Ingolstadt University of Applied Sciences since 2004. After building up a test rig, several thermosyphon systems were tested according to ISO 9459-2 (ISO 1995). Additionally, tests procedures developed at Ingolstadt University have been carried out in order to learn more about the systems´ behaviour under special conditions, e.g. its stagnation behaviour. In the end of 2007, a R&D project was started at the CENTRE OF EXCELLENCE FOR RENEWABLE ENERGY RESEARCH. Objective of the project is the development of an optimised thermosyphon solar hot water heater based on a scientific R&D procedure. A market analysis shows that most thermosyphon systems are still developed by trial and error (Brandmayr and Zörner 2007). This project, however, aims at demonstrating a closed development cycle. The initial steps include the analysis of thermosyphon systems in theory and the transfer of the mathematical model into simulation. The impact of various system parameters on the overall system performance is simulated in a sensitivity analysis. The results, leading to a fictive optimised thermosyphon system are transferred into a system prototype, which is thoroughly tested at the university`s solar-thermal laboratories. The measurement results are used to optimise the prototype and to achieve validation of the simulation model. The optimised prototype system is prepared for mass production by the industrial project partner.