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Experimental study to determine concentrated solar

energy in solar parabolic concentrator

Safa Skouri,Salwa bouadila Kota Pavan kalyanSassi Ben N asrallah M.Tech-Manfg

10926010

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Contents

• Introduction• Literature Survey• Experimental setup• Results • Conclusion• References

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Introduction• Recently medium-high temperature application is an

important topic in the solar energy field.• Demand for energy is projected to more than double by 2050

and more than triple by the end of the century.• Incremental improvements in existing energy networks will

not be adequate to supply this demand in a sustainable way.• Evaluation of the energy arriving at the focus of a mobile

parabolic dish using two types of solar heat exchanger designed.

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Literature Survey

• Shuang-Ying Wua et al. evaluates the overall thermal-electric conversion performance of parabolic dish/ AMTEC solar thermal power system. The overall conversion efficiency of the system could reach up to 20.6% with a power output of 18.54 kW corresponding to an operating temperature of 1280K

• Yong Shunai Applied Monte Carlo ray tracing method coupled with optical proprieties to predict radiation performance of dish solar concentrator/cavity receiver systems.

• Jaramillo and al. for measuring concentrated solar flux evaluation. They shown that the mean value of the temperature on the surface of the copper plate of the calorimeter is lower than when stainless steel is used.

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Experimental setup• The fundamental parts of experimental setup are: o The solar concentrating systemo The receiver (The flat plate calorimeter or solar heat

exchanger)o The data acquisition system and o Instrumentation.

o Thermocoupleso Pyranometer

Figure- I. The experimental setup Source: journal

Experimental setup

Flat plate collector

Figure 2. Flat plate collector. Source:journal.

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• A water calorimeter is a solar concentrated energy evaluation device placed at the SPC focus where the used heat transfer fluid is the water.

• This calorimeter made of steel is constituted of two concentric cylindrical conduits, two plates and two rings.1. Receiving plate2. Distributing plate 3. The sealing ring 4. The polyamide ring

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• The heat flux extracted by the calorimeter is expressed as: Qcc =mw Cpw(T w.outlet - Tw.inlet)

Where; mw is the mass flow rate of water,

Cpw is the water heat capacity, and

(T w.outlet- T w.inlet) is the temperature

difference bettween inlet and outlet.

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Solar heat exchanger

• The solar heat exchanger is a tube exchanger.• It consists of three main components: spherical cavity

exchanger body and the back cover.• The body of the exchanger is a solid cylinder of 140 mm

opening diameter and 240 mm length, pierced by 52 holes with a 10 mm diameter.

• Spherical cavity covered with glass plate placed in the exchanger received face, captures reflected rays.

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Figure 3. Solar heat exchanger. Source:journal.

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Solar heat exchanger(cont.)

• This exchanger offers a large heat transfer area and provides high heat transfer efficiency.

• The heat transfer fluid used is thermal oil.• The heat flux extracted by the heat exchanger is expressed as. Qcc =mo Cpo(T o,outlet-T o,inlet) (2)

Where; mo is the oil mass flow rate,

Cpo is the oil heat capacity,

(To,outlet-To,inlet) is the temperature

difference between inlet and outlet oil.

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Results

• Experimental study of the solar water calorimeter is illustrated and presented inlet and outlet water temperature of the calorimeter placed in the SPC focus under clear sky conditions and global solar radiation around 850 Wm_2.

• The outlet water temperature increase rapidly in the beginning of the experience, then it stabilized at a maximum value around 65°C for an ambient temperature 25°C and a fixed mass flow equal to 0.0192 kg/s.

• The mean difference between inlet and outlet temperature attaint 30°Cduring the experience (6 hours).

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Results(cont.)

• So this calorimeter can be used to certain application requesting means temperature like water desalination, solar cooker and for a fewer mass flow rate used (outlet water temperature can achieve 100°C), steam production application can be take in.

• The energy efficiency changed between 52 % and 83 %. The higher energy efficiency is obtained at noon. The average value of energy efficiency is about 72 %.

• The determined value of concentration factor reach 180.

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Figure 4.Inlet and outlet water temperature of the calorimeter. Source: journal

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Figure 5. Thermal SPC efficiency using water calorimeter. Source :journal

Figure 6. Experimental variation with time of the SPC energy efficiency using SHE. Source: journal

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Conclusion

• Point focus solar concentrating systems will play an important role in different industrial applications like the generation of electricity by solar thermal power, the production hydrogen.

• Calorimeter can be a useful instrument to evaluate the thermal performance of point focus solar concentrating

systems .

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References• F. Kreith, D.Y. Gowami. Handbook of Energy Efliciency And Renewable Energy

2007.• Republique Tunisienne , Ministere de l"industrie, de l"energie et des PME, Ie

plan solaire tunisien 2009.• S.Y. Wua, LX Yiding Cao, Y.R. Li. A parabolic dish/AMTEC solar thermal power

system and its performance evaluation Appl Energ 20I0;87:452-462.• Y. Shuai, X.L. Xia, H.P. Tan. Radiation performance of dish solar

concentrator/cavity receiver systems. Sol Energy 2008;82: 13-21.• S. Ulmer,T. Marez, christoph prahl,wolfgang reinalter, boris belhomme

automated high resolution measurement of heliostat slope errors solarenergy (20 I 0)

• 1. Chaves, M. Collares-Pereira. Etendue-matched two-stage concentrators with multiple receivers. Sol Energy 201 0;84: 196-207.

• P.L. Singh, R.M. Sarviya, lL. Bhagoria. Heat loss study of trapezoidal cavity absorbers for linear solar concentrating collector. Energ Convers Manage 2010;51:329-337.

• l Ballestrin, C.A. Estrada, M. Rodriguez-Alonso, C. Perez-Rabago,L. W. Langley, Barnes Heat flux sensors: Calorimeters or radiometers.Sol Energy

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