Thermophysical Properties of a Cryogenic Pulsating Heat Pipe

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Soenke Teichel M.S. Graduate StudentMechanical
Engineering
Room 1335 ERB
Email teichel_at_wisc.edu
Home Town Hannover, Germany
Thesis Improvements of a Model of a Cavity
Receiver in a Solar Tower
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• Technology Overview Solar Tower

Process flow diagram of the PS10 solar tower
power plant. 1

• The heliostat field, evenly distributed on the
  northern hemicycle (PS10) around the tower,
  tracks the position of the sun and reflects
  radiation onto the cavity receiver.

• Heat transfer fluid (HTF) (e.g. molten salt,
  steam, air) flows through tubes on the receiver
  surface and absorbs incident solar radiation.

• Thermal energy is stored in large units to
  compensate for times when there is little or no
  solar radiation and during peak loads.

• The HTF is routed into a heat exchanger to
  deliver heat for a steam cycle (Rankine, Brayton).

• This cycle converts thermal energy into
  electricity with a nominal output of 11 MW (PS10).

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• Cavity Receiver

• The cavity receiver is formed by welded tubes,
  which contain the heat transfer fluid. The
  receiver face approximates a semicircular
  cylinder shape.

• Reflected radiation enters the cavity through a
  north-facing aperture. The heliostat field is
  built exclusively within the range of possible
  incidence angles onto the receiver.

• The geometry of the cavity-type receiver reduces
  radiative and convective heat losses, forced
  convection losses depend significantly on the
  wind direction.

PS10 cavity-type receiver . 2
SOLUCAR PS10 3
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• Project Objectives

• The model of the cavity receiver is part of the
  Solar Advisor Model (SAM), an analysis software
  tool developed by the National Renewable Energy
  Laboratory (NREL).
• This tool allows to examine and compare
  different solar technologies in respect of
  economical, technological and operational
  aspects.

• A detailed model of a cavity receiver power tower
  was developed by Feierabend 4 which
  incorporates radiation, convection and
  conduction.

• The objective of this project is to improve the
  heat loss model of the cavity receiver, by
  implementing semi-gray radiation heat transfer
  and to improve the correlations for natural and
  forced convection.

References 1 Romero, M., Buck, R. and Pacheco
J. E. (2002). An Update on Solar Central Receiver
Systems, Projects, and Technologies, Journal of
Solar Energy Engineering, Vol. 124, pg.
98-108. 2 SolarPACES Home Page. Available at
http//www.solarpaces-csp.org/Tasks/Task1/ps10.htm
Accessed September 28, 2010. 3 Alejandro
Flores, SOLUCAR PS10, September 27, 2007,
http//www.flickr.com/photos/afloresm/1448540190/
4 Feierabend, L. (2010).Thermal Model
Development and Simulation of a Cavity-Type Solar
Central Receiver System, M.S. thesis University
of Wisconsin - Madison - Solar Energy
Laboratory