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Page 67
November 13-14, 2017 Paris, France
5th International Conference on
PLASMA CHEMISTRY AND
PLASMA PROCESSING
Journal of Biotechnology and Phytochemistry
Volume 1, Issue 2 Plasma Chemistry 2017
Direct photoelectric conversion of the focused
solar radiation on the base of low-temperature
plasma
Gorbunov Nikolay
Admiral Makarov State University of Maritime and Inland Shipping, Russia
Amodel of the direct photoelectric conversion of
concentrated solar radiation in a plasma ignited in a
heat pipe filled with a mixture of sodium vapor and krypton
is developed. The model considers the non-homogeneous
distribution of the alkali atom density in the heat-pipe
volume and the thermionic effect of a cathode. The model
treats a hot plasma core in a local thermal equilibrium (LTE)
state and takes into account non-equilibrium layers near the
converter walls. The model is employed to calculate an open-
circuit voltage, a plasma resistance, a short-circuit current, an
energy flux of positive ions directed toward the cathode, and a
conversion efficiency of the solar radiation. We found within
the framework of a two-temperature model that the reduction
of the electron temperature by 20% compared with the LTE
plasma temperature took place at the outer boundary of the
ionization layer near the cathode. This non-isothermal model
predicts a rather high value (approximately 33%) for the
conversion efficiency for a 300x solar radiation concentration
ratio. We analyzed the impact of chemical reactions on the
plasma conductivity in the external cooling loop region. Two
possible explanations for an abnormal high conductivity in an
oversaturated vapor of alkali metals are considered. First, the
reduce of the effective ionization potential takes place because
of the high concentration of alkali metal molecules. Second,
a high concentration of micro drop components in the vapor
may serve as an additional source of free electrons through
the thermal emission effect. The increase of the ambipolar
electric field strength in the near-anode region due to non-
equilibrium shape of electron energy distribution function
(EEDF) is considered. Thus, the formation of the non-
equilibrium EEDF in the photo plasma may play a significant
role in the problem of attainment of maximal possible values
of the converter efficiency.
J Biot Phyt 2017