PERFORMANCE ANALYSIS OF PARABOLIC TROUGH COLLECTORSPTC

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PERFORMANCE ANALYSIS OF PARABOLIC TROUGH
COLLECTORS(PTC)

• By
• Satyen Moray

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OVERVIEW

• What is a PTC?
• Its terminology
• Different design considerations for such a
  system.
• Simulation of this model.
• Results from the simulation.
• Conclusion

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COMPONENTS IN A SOLAR THERMAL SYSTEM

• Solar Collectors
• Thermal Storage System
• Piping Systems
• Heat Exchangers
• Controls

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CLASSIFICATIONConcentration Ratio(CR)Aperture
Area/Absorber Area
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TYPES OF FOCUSSING COLLECTORS

• Parabolic Trough Collector. (Imaging
  Concentrator)
• Fresnel Lens Collector. (Imaging Concentrator)
• Compound Parabolic Collector (CPC).
• (Non Imaging concentrators)

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PARABOLIC TROUGH COLLECTORS(PTC)CRgt10
Schematic of a PTC
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PARABOLIC TROUGH COLLECTORS(PTC)

• Also called as line-focus concentrators
• Why Parabolic?
• The incident radiation should bisect at the
• contact point and be tangent to the receiver
• tube,which can be obtained by using the
• profile of a parabola.

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DESIGN CONSIDERATIONS

• To reduce the heat loss due to convection and
  conduction, the space between absorber and cover
  is evacuated.
• The absorber is painted with a high absorptance
  paint.
• Cover material is selected to have high
  transmittance. A reflective coating is also
  applied on the inside of the cover to reflect the
  radiation back onto the absorber.

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HOW DO WE SIMULATE THIS COLLECTOR?
Qu It x Fr x A x No - Heat loss
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MODEL DIAGRAM
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MODELING THE COLLECTOR

• Heat gained by the absorber is given by
• Qu (It x No x Ac) - (heat loss from the
  collector)
• Where,
• It, beam radiation depends on type of tracking
• used.
• No, optical efficiency depends on
• mirror reflectance , transmittance of cover,
• absorptance of receiver etc.
• Ac, collector area
• Major heat loss is by radiation as the other
  forms of heat transfer are negligible and are
  eliminated to some extent using proper design.

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MODEL PARAMETERS

• Width of the collector 4 m
• Concentration Ratio 50
• Diameter of Cover tube 0.06 m
• Mass flow rate in collector loop 0.04 kg/s
• Mass flow rate in load loop 0.03 kg/s
• Material of tube Stainless steel

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RESULTS
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RESULTS
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RESULTS
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CONCLUSION BASED ON GRAPHS

• Although the results are also plotted for 2-Axes
  tracking, the PTC system is commonly used in
  single axes tracking mode only.
• Based on the results obtained from the graphs, a
  PTC tracked along the polar axis seems to give
  the highest temperature of exit water for the
  given conditions. Based on this conclusion,
  further analysis is performed on a system tracked
  along the polar axis.

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RESULTSCR 50, W 4m and L20 m
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RESULTSCR 50, W 4 m and L 20 m
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RESULTSCR 50, W 4 m and Length 20 m
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ECONOMIC ANALYSIS

• The system is capable of supplying steam at a
  temperature above 165 C and at the rate of 246
  lb/hr for about 1070 hours in a year in Dayton.
• We have seen companies purchasing steam at a rate
  of 8.49 per thousand pounds. This gives a
  saving of about 2,235 per year.
• Estimating that such a system would cost about
  10,000 to install, the simple payback would be
  about 4 years.
• From the analysis, this mass flow rate was found
  to give the minimum payback.

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APPLICATIONS

• All the places which require energy(heat) in the
• range of 300 - 400oC can use the line focusing
• collectors. Some typical industrial applications
  are
• Supply steam to large scale laundry complexes.
• Gila bend pumping system.
• Generate steam for power generation.

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CONCLUSION

• From the results we can see that these systems
  can be used to generate steam for various
  applications.
• The best system seems to be the one that is
  tracked along the polar axes.

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• QUESTIONS?
• QUESTIONS?
• QUESTIONS?