solar still pyramid

8/18/2019 Solar Still Pyramid

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Thermal – economical analysis and comparison betwe pyramid configuration and single slope solar stills


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Problem Definition

Water-Water everywhere but no where to drink.


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So researchers are trying to find different methods and arrangements to increase the effiacceptance of Solar stills.

In last seminar we already had viewed a very good presentation on various types of sola

Today we are giving a try to Bio-mimicry of solar still with Great pyramid of Giza(in Egyp

Already some numerical “coincidence” quickly emerge from its size:

The slant height (6 11.5 ft.), when divided by one-half the length of its side (377.9 ft.), reenigmatic ratio known as the “golden ratio”.It is a ratio that is used by Photographers and graphic designers all over the world .


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Can Bio- mimicry of Egypt Pyramid increase the efficiency of solar still desa


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Experimental Apparatu


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To study this, a team of researchers from Alexandria University, Egypt made a scale down moand to compare the results obtains they choose single slope solar still configuration.

btain "omparable reult they "hooe thee pe"i#"ation$

Transitivity of glass

Absorptivity of glass

Absorptivity of water

Specific heat of water

Area of floor covered

Film coefficient of heat transfer

Area of glass of pyramid

Area of glass of single slope

Ground surface reflectivity

Latitude

Specific heat


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omparion o( reult whi"h are (ound by doin' ex


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/onthly avera'e variation o( daily olar thermal ener'ie (or 0yramidal and&in'le olar till

E E! A A&7E 7AA! 87 097A/ &A0E & )E7 !A !A! 8 &):E &:E A:9 A?E7A)E 9EA7:9 E! 7AA! A A&7E 7AA! 87 097A/ A7E 4@E A:9 A?E7A)E 9EA7:9 &:A7 7AA! :&&E& 87 097A/ &!:: & 1@ )E7 !A &)E 7A! 8 &:A7 7AA! :&&E& ! !E E! 7AA! 87 097A/ &A0E &!:: &


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February 1994 (A=1.5274 m2) July 1994 (A=1.5274 m2)

Figures show that resultant incident solar energies received by the single slope still is that received by pyramid in winter( february ) while it is 5%lower in summer ( july )


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February( winter ) July( summer )

Due to large radiation losses from cover surface of the pyramid, the daily yield of the still is 30% higher than that of the pyramid in winter and 3% higher in summer


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February( winter) July( summer)

From the figures it is clear that the single slope still is more efficient than pyramid shaboth in summer and winter


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February

July


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February July

qr=radiation heat transfer flux

qc= convective heat transfer flux

qe= evaporative heat transf


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February July


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Monthly average yield for both pyramid and single slope still


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Monthly average efficiency for both pyramid and single slope still


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onomi" "omparion o( pyramid and in'le lope

E i t d d lt


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E"onomi" tudy and reult

8a"tor ae"tin' produ"t water unit "oto( dealination$-

• Bnit i*e

• &ite lo"ation

• 8eed water propertie

• 0rodu"t water reCuired Cuality

• Duality ta availability


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E"onomi" Advanta'e$-

The main economic advantages of solar distillations are

• It does not require much infrastructure

•

Simplicity to locally design• Installation

• Maintain and operate

Economic Disadvantage:-

Its main disadvantage is the unit size limitation due to large area


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Economic analysis of water unit cost:-

Capital Recovery Factor (CRF),

First Annual Cost (FAC),

Sinking Fund Factor (SFF),

Annual Salvage Value (ASV),

Annual Cost (AC),

and Annual Cost per Liter (AC/L) can be expressed as:-

CRF = i (1+i)n / [ (1+i)n – 1 ]

FAC = P (CRF)SFF = (i) / [ (1+i)n – 1 ]

ASV= = (SFF) S

AC = FAC + AMC – ASV

AC/L = AC / M

Where: AMC is annual Maintenance Cost, and has been taken as 15 % FAC.


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Table (1) Cost Breakdown of Solar Stills InLE ( LE ! "#$ %

Table (#) &roduct 'ater nit Cost I


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Conclusion:-

• Analyti"al tudy and "omparion between two olar till"on#'uration the 0yramidal and in'le lopeF have been preented

• A mathemati"al model ha been developed to imulate the thermal

analyi o( thee "on#'uration and tudy their per(orman"e.• !he weather meteorolo'i"al data o( Awan ity wa uedF in"e it i

the mot reliable meaured data (or both dire"t and diuedradiation.

• n the bai o( the yearly per(orman"e reultF the in'le lope tillwa (ound to be li'htly more eG"ient than the pyramidal one.

• !he olar ener'ie re"eived by the in'le lope till i + @ hi'herthan that re"eived by the pyramid in winter while it i 5 @ lower inummer

• ue to the lar'er radiation loe (rom the "over ur(a"e o( thepyramidF the daily yield o( the in'le lope till i 3 @ hi'her thanthat o( the pyramid in winter and 3 @ hi'her in ummer.


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• !he pyramid tilt an'le o( 5 de'ree ;very near to the )r0yramid o( )i*a an'le o( 52 de'ree> 'ive the bet tillprodu"tivity. &i'ni#"ant redu"tion take pla"e when the in"reae above 6 de'ree.

•

the "ot o( olar ditillation produ"t water o( .12 :.E.HlitIHliter> "ould be a""eptable a "ompared to water tran

solar still pyramid

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