Solar Fresnel Power Plant

7/29/2019 Solar Fresnel Power Plant

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GREEN LINE POWER PVT LTD PONDICHER

Created and calculated By M SIV

Design of solar paraboliclength of collector 3.6576

Aperture(w) 2.45

Concentration ratio 16

51.3296

Outer diameter of tube 0.047731

Efective aperture area (W-Do)L

Absorber tube area 3.145*Do *

Absorber innerdiameter

Glass cover Outer diameter

Glass cover Inner diameter

Specular reflectivity of concentrator surface

Glass cover transmissivity for solar radiation

Glass cover emissivity/absorptivity

Absorber tube emissivity/absorptivity

Intercept factor

Date

Time

Hourly beam radiation

Hourly global radiationAmbiant Temperature

wind speed

Mass flow rate of Thermic fluid

Inlet Temperature

LAT()

Angle of incidence @ April 15 () 105 th day

Hour angle ()


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Slope of apture plane()

Angle of incidence

Properties of Thermic fluidMean fluid Temperature

Density

Specific heat capacity

Kinamatic viscosity

Thermal conductivity

Average velocity

Reynolds number

Prandtl number

Tape twist ratio

Nusselt number

Heat Transfer coefficient

Colletor heat removal factor

Assume Overall heat transfer coefficeColletor heat removal factor

Heat removal factor

Concentration ratio

Beam Radiation

Absorbed flux

Usefull heat gain rate

Rate of heat loss

Avarage Temperature of absorber Tube

Calulate "U" CORRESPONDING TO THIS VALUE OF

Assume Temperature attained

Mean Temperature of air between tube andAt this Temperature properties


Kinamatic viscosity

Prandel number

Radial gap

Rynolds number

Ambient air temperatureEffective thermal conductivity 0.159776

Convective heat transfer coefficent absorbeMean temperature of air between the cover and ambient

Properties of air


Kinamatic viscosity

Rynolds number

Nusult number

Heat transfer coefficent outside su

Overall heat coefficent


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Sky Temperature

AND

The two values of q/l match wiwhich also matches the original guess

Equating heat gained by the fluid t


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RY

RAMAKRISHNAIAHMTech Thermal Engineering

rough collector(Tracking Mode 11) Glass Tubem 12 ft

m 8.038057743 ft

m 47.73074405 mm

8.786540031 m

L 0.549158752 m^2

0.0381 m

0.063 m

0.056 m

0.85

0.85

0.88

0.95

0.95

15-Apr

1230 h 12.5 LAT

705 w/m^2

949 w/m^230 C

5.3 m/s

0.0986 kg/s

150 C

11.92 Deg

9.414893347 Deg

16.94418733 -7.5


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9.494661091

250 C

750.3 kg/m^3

2.449 kj/kg

2.45E-06 m^2/s

0.119 w/m k

0.115119399 m/s

1.79E+03

37.83056735

4

6.14E+01

191.9093915 w/m^2 K

t 13.1 w/m^2 k 13.50.919010067

0.906166031

16

0.993319235

467.8641299 W/m^2

2919.005206 W

1191.901701 W

190.7713882 C

pm and show that it is equal to the assumed value.

by the cover 78.5 C

Cover 134.6356941 C

0.03526 w/m k

2.45E-05 m^2/s

0.7

0.004134628

2.22E+02

300 K0.446059798 3.86E+00 0.542577

tube and the glass cover(hp-c) 5.017233929 w/m k325.75 K

0.027 w/m k

1.60E-05 m^2/s

1.58E+04

6.83E+01

rface of cover(hw) 29.2746592 W/m^2 K

310.3233894 w/m


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294 K

323.2741804 w/m

th each other.the corresponding value of "U" 13.39247 w/m^2

the useful heat gain rate(Exit Temperature) 162.08841 C


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0.156597

38.1 mm

63 mm

56 mm

303 K

Deg 0.991445 Deg

Aperture area

Outer Diameter

rim angle


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1 Radiation loss from Glass to sky

2 Covective loss fromm the galss to atmospher

w/m^2 K

463.7714 K

351.5 K

407.6357 K

27 C

52.75 C


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21 C

k


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Principle and operation:

A linear solar fresnel solar plant uses an array of single axis,

The compact linear fresnel solar power system, however, u

as in the solar parabolic trough system.This type of system

linear solar fresnel system heat water to produce steam at

avoiding the need for a heat exchanger to produce steam f

Advantages1 Main advantages of linear Fresnel are its lower investment

2 The struture also has a low profile,with mirrirs just one or t

3 Linear Fresnel collectors also make more efficient use of la

The collectors also easier to maintain since they have fewe

4 The three leading versions of linear Fresnel technology gen

5 Linear fresnel technology costs between 50 to 60% of cost

6 A linear solar fresnel solar plant can be hybridized with fos

7 The absorber tube is simpler and less expensive than that o

Disadvantages1 A linear solar fresnel solar plant doesn't produce a fluid te

so its thermal efficiency for conversion of solar power to el

Design and arrangement of mirrors

The linear Fresnel collector concepts uses a number of rows of relative


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Axis Tracking mirrors that concentration the radiation on a linear recei


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As per above pictures How to adjest mirrors and receiver tubes in cor

For this we will use ray Trace simula

will use for o

Large numbe

The direction

Reflecting ray follows the priciple that t

Tracking angle of the ith reflecctor calc

= ( - )/2

Single Axis tracking about the polar axis approaches with in 4% the rad

Tracking about East-west horizantal axis

Take Example of one day rays angles calculations:

Date

Time

Hourly beam radiation

Hourly global radiation

Ambiant Temperature

wind speed

Inlet Temperature

LAT()


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Angle of incidence @ April 15 ()

Hour angle ()

Slope of apture plane()

Tracking about East-We

Fresnel mostly convex shaped mirro

Parabolic concentrators is the uniqu

In this system we will adopted cylindrical mirro

the Focal length "f" of the mirror,and Tracking

The radius of curvature we are gand for focal length the distence fro

Radius of curvature for mir

ri =


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East-West orientation

possibly the most complex tracking. The angle

During the winter, the mirrors tilt down toward

(the plane of the sun's motion is co-incident wit

This tracking will likely need to be accomplishe

The North-South orientation is similar to the polar orientation, but m

with the shallowness of the suns an

Since we do not wish to tilt the arra

Also, the reflectors move between

and a total daily loss of the integral

One Example

Mirror arrangement


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Glass mirrors

As far as curvature goes, there are s

there are geometric limitations to a

Our best results for curvature wher

about seven inches of unconcentrat

image sizes of about 3 inches were

the limits of concentration1 As light travels down different angle

at another angle it will be out of foc

2 At twice the focal distance (%100 o

3 In an east-west axis system, the sun

the extra path length of Square root

The best achievable theoretical fix

This corresponds to a maximum con

since the sine changes quickly arou

A north south axis orientation will exp

Examples of Fresnel power plants:

1 Novatec

2

Kimberlina


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Ausra

Liddell powe

Carrizo Ener

http://www.novatec-biosol.eu/inde

http://www.ausra.com/technology

Example:

Apture area

Average solar radiation f

Average sunlight availab

Total Energy out put Ap

With 65% concentration

Example:

Water flows inside of re

passing through the tub

Inner diameter of tube

water velocity

Tube wall temperature

Inlet water temperature

Outlet water temperatu

Length of tube

Bulk mean te

Properties of

Rynolds num

Heat tr


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Solar fresnel alignment of collectors and Receiver Tube

linear solar mirrors to reflect sunlight onto a receiver tube.In that way it is similar to a solar parabolic trough sys

ses a 'parabola' made up of ten flat mirrors that each rotate to follow the sun,Instead of a more expensive parab

allows theCompact Linear Fresnel Solar Mirrors.flat solar mirrors to remain near the ground, avoiding wind loads

400 C in the absorber tubes. The steam is used directly to drive a turbine in a standard Rankine cycle to produce

rom some other high temperature fluid.

and operational costs.Firstly,the flat mirrirs are cheaper and easier to produce then parabolic curved reflectors a

wo meters above groud.This means the plant can operate in strong wind and it can use a lightweight,simple colle

nd,packing more mirrors closer together compared to parabolic through.

r moving parts and they can turn down during the night for protection from sand and to allow for automated cle

erate steam directly,which means they do away with the need for expensive and performance-reducing heat exc

of a parabolic trough collector per square metre.

il fuel backup to be used for electrical generation when the sun isn't shining

f the parabolic trough system, because multiple solar mirrors reflect solar power to a single absorber tube and th

perature as high as the parabolic trough or parabolic dish solar concentrators,

ectricity is lower.

ly small one


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ver.


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ect mannar

tion software

ptical efficiency simulation of the concentrating collector.

r of rays of incident radiation throughout the system for reflecting surface.

and point of intersection of incident ray with the reflecting surface are determine

e angle of reflection equals the angle of incidence

lated according to Mr.Rabl

= is the angle between optical axis and the line from focus to reflector

= is the incident angle of the sun relative to the aperture normal.

iation avalability of the collector.

15-Apr

1230 h 12.5 LAT

705 w/m^2

949 w/m^2

31.9 C

5.3 m/s

150 C

11.92 Deg


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105 th day 9.414893 Deg

16.94419 -7.5

9.494661

t horizantal Axis

COS = COS(COS^2 + TAN^2)^0.5

rs for low and medium concentrating one axis tracking or stationary collectors.

e reflector shape that focuse beam radiation into a single point.How ever the manufacturof parabollic reflector i

s with different curvature.The mirror radius of curvature "ri "depends on

ngle

oing to implement ,Tracking angle for perpendicular incident radiation ( = 0)m mirror center to absorber center.

ors :

(2*f)/cos


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f the mirrors is determined by the vector towards the sun projected onto the vertical axis running north-south

s the south,coming up till noon and decreasing again. The severity of this angular adjustment decreases from win

h the plane of the parabolic trough), and reverses direction during the summer, as the sun rises slightly north an

by sensors rather than formulas.

y be flat or cylindrical on the ground.Tracking may be as simple as in polar or it may have hidden complications (

gle parallel to the axis of the collector would be severe in winter if this orientation were laid flat on the ground.

y towards the south for construction cost reasons (same as polar), and wish to collect energy during the winter, T

lus and minus 22.5 degrees of tilt from 9am till 3pm. Thus there will be a maximum half angle loss of cosine 22.5

of cos (1/2 theta) from theta =-22.3 to 22.5

8 Rows 4 reflectePrimary mirrors

Number of rows

Number of sets

Mirror width

Length

Mirror spacing

Total mirror area

incident angle of

= is the angle

= is the inciden


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Included angle of

Radius of c

Mirror

12

3

4

5

Note: "That mean

tructural advantages to having fewer reflectors, each with a concentration ratio of 5 or so. Although a perfect pa

system which must track the sun. Also, we found a perfect parabolic shap difficult to achieve under non-tracking

with 2'x 1' panels of glass, with an image size of just under an inch and a half (concentration ratio of about 20),

ed light around the focus (ie: only 75% of the mirror assumed the curve, since the ends, for whatever reason, do

chieved with mylar on thin plywood, but this could not be achieved over the entire length of the focus.

s parallel to the axis of the concentrator, it travels different distances before reaching the absorber. Thus, if the a

us. The percentage out of focus is inversely proportional to the amount of concentration possible.

t of focus), the image is the same size as the width of the reflector. At 1.5 the focal length (%50), the image will

moves from 45 degrees at 9 am to 0 at noon to 45 again at 3 pm. If this system were perfectly in focus at noon,

of two (~1.4) in the morning and evening would correspond to%40 out of focus or 2.5 times concentration.

ould be to have the system focused perfectly at 22.5 degrees, so that the absorber is too close at noon and too f

centration of 3.27 (change in path length is 1/cos45 - 1/cos22.5 = 1.41 - 1.08 = .33 ->% out of focus of .33/1.08=

d 45 degrees, greater ratios could be obtained by sacrificing efficiency at the extremes.

erience this distortion less severely due to the fact that the seasonal angular deviation of the sun is much less tha

The Kimberlina solar power plant has a 5MW capacity and although the size appears


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r station

y Solar Farm(CESF)

x.php?article_id=5&clang=1

1 m^2

or indian conditions 750 W/m^2

le from morning 8 am to 4 pm 8 hours/day

erture area x solar radiation x hours 6000 Wh/day 6

efficiency the energy out put 3.9 KWh/day 3355.638

1423.5 KWh/year

eiver tube of 20 mm diameter and 3 m long at a velocity of 0.03

.The tube wall is maintained at constant temperature of 160 C.Find heat tra

20 mm 0.02

0.03 m/s

160 C

40 C

re 120 C

3 m

mperature 80 C

water at 80 C

Density 974 kg/m^3

kinamatic viscosity 3.64E-07 m^2/s

Prandel number 2.22

Thermal conductivity 6.69E-01 W/Mk

ber 1.65E+03

Thiis Rynolds number value below 2300,this flow is laminar

Nusselt Number 3.66

Nusselt Number hD/Kheat transfer coefficent 122.3721 W/m^2K

nsfer 1848 W


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Absorber area :Aperture area :

em. Gross area:olic shaped mirror,

.

lectricity,

nd so are readily available from manufacturers worldwide.

ctor structure.

ning.

angers.

e absorber tube doesn't need couplings as the receiver tubes for the parabolic trough and parabolic dish syste


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.

304.9 K


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Deg 0.991444861 Deg

too expansive.

Concentration ratio = Collector area/Focussed area = normally 26/1


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ter solstice till equinox, when no angular adjustment is needed

comes slightly south by noon.

e don't know). Due to the latitude of the Factor E farm, the end losses associated

he factor E Farm team has shied away from this orientation as well.

d mirrors with a noth - south Tracking Axisre cylindrical with different small curvatures.

8

4

0.5

4

0.15

approximatly 64

the sun relative to the aperture normal. 0

2.995496019

0.978147601

12.26808714

between optical axis and the line from focus to reflector.

t angle of the sun relative to the aperture normal.


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sun relative apeture angle ( )(perpendicular incident radiation)

rvature of different mirrors

Focus (f )

Radius of mirror

(ri)

6.28 3.14 2.5 5.00751792318.26 9.13 2.6 5.266724875

28.81 14.405 2.65 5.472032747

37.6 18.8 3.2 6.76068769

44.71 22.355 3.6 7.785087972

s Radius of mirror curvature mainly depends on the focal length of the mir

abola could have a concentration ratio of 50 or more

conditions.

it

not curve).

rray is in perfect focus at one angle,

e half the width of the reflector.

ar at 3pm, but neither as badly as if the system were in focus at noon.

%30.5).

n its daily variation.

small


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Kwh

Kcal

m/s.The water gets heated from 40 C to 120 C.while

sfer

m


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the area of absorberthe area in which solar radiation enter the collector

the area based on outer dimention of collector

ms do, because the absorber tube is fixed.


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m

m

m

m^ 2

Deg


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or and tracking angle.

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Solar Fresnel Power Plant