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Titre : Modelling electric energy and heat transfer in small autonomous solar systems
Mots-clés : flat solar collector, PV module, autonomous solar installation, con-trolling the circulation of the operational factor, energy exchange modelling
Résumé :

The paper presents a new solution of a solar installation structure intended to sup-port warm utility water preparation, which is intended for operation in the autonomy of the heat source. Structure of such solar installation which is a combination of a photovoltaic module and a flat solar collector allows using the effect of operation coherence of these devices in a one system, which ensures the support of warm utility water preparation with no need to supply the system of heat exchange enforcement and control with electric energy. This solution is adequate for the needs of farms located in rural areas, where stoppages in electric energy supply still occur, which for active solar installations is a considerable threat leading to their damage.

For the needs of implementation of autonomous solar installation in practice, a methodology was developed which gives basis for designing and testing this type of solar systems. A developed methodology is based on analytical models, which are completed with dependencies empirically determined. Analytical dependence was developed to describe the power generated by PV module, which was verified for the following independent variables, i.e. density of the solar radiation stream, working temperature, the area of a module and a constant which is operational efficiency of this module. Efficiency of the module which supplies a circuit pump of the constant voltage was taken down to dependence which binds constants determined for PV module in STC conditions and the stabilization voltage set in the circuit pump. Power generated by a module was used to explain the intensity of operational factor flow in a solar installation with a logarythmic dependence which was set empirically.

A dimensionless coefficient of heat removal from a collector was used in the paper for combination of the electric energy stream generated by a module with a stream of induced heat in a flat solar collector. Based on the coefficient determined in such a way, a set of models describing energy conditions of an autonomous solar installation, which were solved in Matlab Symuling programme, was developed. It should be emphasised that the developed models, describe well the processes occurring in the autonomous solar system, which was verified in tests of various density variability of solar radiation. Moreover, for the needs of verification of the models, a density analysis of solar radiation which reaches the surface inclined under the angle 30º and the south exposition, was carried out.

Travail effectué à : w Katedrze Energetyki i Automatyzacji Procesów Rolniczych, Uniwersytet Rolniczy w Krakowie
Utilisez, s’il sous plaît, le modèle ci-dessous pour citer cet article : Knaga, J. (2013). Modelling electric energy and heat transfer in small autonomous solar systems. Inzynieria Rolnicza, 2(144),
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