The purpose of this thesis was to design a control strategy for a solar combi-system. This combi-system has two storage tanks, one for floor heating and one for domestic hot water, but it has only one auxiliary heater. The purpose of the research was to find a control strategy in order to make the best use of this single auxiliary heater, but this goal has been adapted.
In the first chapter, Introduction, the framework of projects surrounding this thesis is outlined; this thesis forms a part of the research done in the Rebus project. It is directly linked to three of Rebus’ participants; SERC, UiO and SolarNor. Furthermore is the main goal stated and it is explained why it has been slightly altered. This change of goal makes Chapter 3 the back bone of this thesis, instead of Chapter 5 and 6 what might be expected judging from the title.
The second chapter, System description, starts with a general overview of solar heating systems. Then a more specific description of the analysed system is given. This second part emphasizes on place and type of sensors and the measurements that are done.
The third chapter, Submerged buoyant jet, forms the center point of this thesis. The submerged buoyant jet forms a very important passive control mechanism in the whole system. An analytical analysis based on literature and publications was used and validated with measurements. It turned out that the buoyant behaviour does not have an substantial contribution to the heat exchange of this jet. It is proven that the heat exchange is mainly caused by forced convection. A crude mathematical model is proposed.
The fourth chapter, Immersed DHW tank with internal heat exchanger, was supposed to have a model for the thermal behaviour of the immersed DHW store as the outcomming. This goal it not reached to a satisfying level, due to practical limitation. The practical limitations are outlined and recommendations are made to improve the model.
In the fifth chapter, System model, the proposed models of Chapters 3 and 4 are implied in Matlab Simulink and are simulated. It shows that the models do not resemble the system behaviour. Recommendations are made for improvements.
The sixth chapter, Control strategy, contains only recommendations, due to the lack...
