Workshop: Design of a solar collector

Citizen Association Ekosol, in cooperation with CRP Tuzla, realized the workshop “Practical Design of Solar Collectors”. The workshop is about the practical production of solar collectors and was held in the laboratories of public School for Mechanical engineering in Tuzla. The workshop consists of two parts, theoretical and practical, it was held in two sessions, namely on December 15, 2018. the theoretical part on renewable sources was done and the practical part was realized on 22.12.2018. The workshop was attended by 14 participants of different ages. These were students of secondary mechanical and electrical engineering school together with their professors, and several students from the University of Tuzla. The workshop was led by Senad Hasanbegovic and Ismet Salihovic, who tried to pass on their knowledge of solar collectors and renewables to all participants. Senad Hasanbegovic and Ismet Salihovic provided valuable tools and accessories necessary for the workshop.

During the workshop, our team, with the help of a mentor, was able to make a functioning solar collector.

More about the solar collector

A solar collector is a device that converts sunlight energy into thermal energy. There is often confusion between photovoltaic panels and solar panels, but their operation and purpose are quite different. While the role of photovoltaic panels is to convert light energy directly into electrical energy, the role of solar collectors is to convert light energy into thermal energy. The question is, why to use solar collectors at all when we can get electricity from photovoltaic panels that we can later convert into thermal energy? The difference is the degree of utilization! Photo-electric energy conversion is still quite inefficient with today’s technology and it is in the 20% operation rang for commercial photovoltaic panels, there are also more efficient designs, but they are unavailable to ordinary consumers or simply too expensive. Solar panels offer a favorable solution if we want to convert simply sunlight into thermal energy. Since solar collectors use the principles of radiation absorption in black bodies in a heat-insulated environment for their operation, their working principles are not hard to understand. Most solar collectors work by passing tubes (usually made out of copper) that are painted black or have an black absorber attached to themselves to heat the work fluid. As sunlight shines on to the black surface it is mostly absorbed, because copper is a very good conductor of heat, it is effectively transferred to the fluid (usually water). To further enhance the system, it is usually placed in vacuum containers or the system tubes are placed in glass vacuum tubes similar to those in thermos bottles. Why use vacuum tubes? So that the absorbed heat does not diffuse into the surrounding space, and to raise the temperature of the system as much as possible, as the only transparent thermal insulator is a vacuum then this approach is most commonly applied. With systems implemented as metioned above, the degree of efficiency can go up to about 70% depending on performance and location.