Sensitivity analysis of the efficiency of a parabolic-trough solar collector

The text presented below analyses the variation of the performance of a parabolic trough solar collector, when some of the parameters that govern its operation vary due to dirty mirror, degradation etc. In order to reach that point, it will be seen how the human has made use of solar energy with different purposes, through history until it has been reached the point where solar technology has the widespread use and in such a variety of technologies as it has today. As in this project, the technology analysed is the solar collectors, it is going to make more emphasis on solar thermal technology. They will be explained in detail how the parabolic trough collectors are, analysing from its different components, to its thermal performance. Once acquainted with this technology, it will be seen which tests will be carried out. Finally it is going to be explained how the model, used for the simulation and implementation of the relevant tests, has been developed. It will also be explained how the model has been validated, for once validated, proceed to the sensitivity analysis of the collectors.

Optimization of solution-processed oligothiophene:fullerene based organic solar cells by using solvent additives

The optimization of solution-processed organic bulk-heterojunction solar cells with the acceptor-substituted quinquethiophene DCV5T-Bu-4 as donor in conjunction with PC61BM as acceptor is described. Power conversion efficiencies up to 3.0% and external quantum efficiencies up to 40% were obtained through the use of 1-chloronaphthalene as solvent additive in the fabrication of the photovoltaic devices. Furthermore, atomic force microscopy investigations of the photoactive layer gave insight into the distribution of donor and acceptor within the blend. The unique combination of solubility and thermal stability of DCV5T-Bu-4 also allows for fabrication of organic solar cells by vacuum deposition. Thus, we were able to perform a rare comparison of the device characteristics of the solution-processed DCV5T-Bu-4:PC61BM solar cell with its vacuum-processed DCV5T-Bu-4:C-60 counterpart. Interestingly in this case, the efficiencies of the small-molecule organic solar cells prepared by using solution techniques are approaching those fabricated by using vacuum technology. This result is significant as vacuum-processed devices typically display much better performances in photovoltaic cells. Keywords