Solar Fresnel Power Plant

GREEN LINE POWER PVT LTD PONDICHERRY

Created and calculated By M SIVARAMAKRISHNAIAH

Design of solar parabolic trough collector(T length of collector Aperture(w) Concentration ratio

3.6576 2.45 16 51.3296

Outer diameter of tube

0.047731

Efective aperture area Absorber tube area

(W-Do)L 3.145*Do * L

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 radiation Ambiant Temperature wind speed Mass flow rate of Thermic fluid Inlet Temperature LAT(φ) Angle of incidence @ April 15 (δ) Hour angle (ω)

105 th day

Slope of apture plane(β) Angle of incidence

Properties of Thermic fluid Mean 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 coefficent 13.1 w/m^2 k Colletor 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 Tpm and show that it is equal to t

Assume Temperature attained by the cover Mean Temperature of air between tube and Cover At this Temperature properties Thermal conductivity Kinamatic viscosity Prandel number Radial gap Rynolds number

Ambient air temperature Effective thermal conductivity

0.159776

Convective heat transfer coefficent absorber tube and the glass cover(hp Mean temperature of air between the cover and ambient Properties of air Thermal conductivity Kinamatic viscosity Rynolds number Nusult number Heat transfer coefficent outside surface of cover(hw) Overall heat coefficent

Sky Temperature AND

The two values of q/l match with each other.the corresp which also matches the original guess

Equating heat gained by the fluid to the useful heat gain rate(Ex

PONDICHERRY

By M SIVARAMAKRISHNAIAH MTech Thermal Engineering

arabolic trough collector(Tracking Mode 11) m m

Glass Tube 12 ft 8.038057743 ft

m

47.73074405 mm

3.145*Do * L

8.786540031 m 0.549158752 m^2

0.0381 m 0.063 m 0.056 m 0.85 0.85 0.88 0.95 0.95

1230 h

15-Apr 12.5 705 949 30 5.3 0.0986 150 11.92 9.414893347 16.94418733

LAT w/m^2 w/m^2 C m/s kg/s C Deg Deg -7.5

9.494661091

250 750.3 2.449 2.45E-06 0.119

C kg/m^3 kj/kg m^2/s w/m k

0.115119399 m/s 1.79E+03 37.83056735 4 6.14E+01 191.9093915 w/m^2 K

sfer coefficent 13.1 w/m^2 k

13.5 0.919010067 0.906166031 16 0.993319235 467.8641299 2919.005206 1191.901701 190.7713882

W/m^2 W W C

THIS VALUE OF Tpm and show that it is equal to the assumed value.

ture attained by the cover

78.5 C

ween tube and Cover

fficent absorber tube and the glass cover(hp-c)

oefficent outside surface of cover(hw)

134.6356941 C 0.03526 w/m k 2.45E-05 m^2/s 0.7 0.004134628 2.22E+02

300 K 0.446059798

3.86E+00 0.542577 5.017233929 w/m k 325.75 K 0.027 w/m k 1.60E-05 m^2/s 1.58E+04 6.83E+01 29.2746592 W/m^2 K 310.3233894 w/m

294 K 323.2741804 w/m

q/l match with each other.the corresponding value of "U"

d by the fluid to the useful heat gain rate(Exit Temperature)

13.39247 w/m^2 k 162.08841 C

Outer Diameter

rim angle

0.156597

Aperture area

38.1 mm 63 mm 56 mm

303 K

Deg

0.991445 Deg

1 2

w/m^2 K

463.7714 K

351.5 K 407.6357 K

27 C

52.75 C

Radiation loss from Glass to sky Covective loss fromm the galss to atmospher

21 C

w/m^2 k

Principle and operation:

A linear solar fresnel solar plant uses an array of single axis, linear solar mirro The compact linear fresnel solar power system, however, uses a 'parabola' m as in the solar parabolic trough system.This type of system allows theCompa

linear solar fresnel system heat water to produce steam at 400 C in the abso avoiding the need for a heat exchanger to produce steam from some other h

Advantages 1 2 3 4 5 6 7

Main advantages of linear Fresnel are its lower investment and operational c The struture also has a low profile,with mirrirs just one or two meters above Linear Fresnel collectors also make more efficient use of land,packing more m The collectors also easier to maintain since they have fewer moving parts an The three leading versions of linear Fresnel technology generate steam direc Linear fresnel technology costs between 50 to 60% of costs of a parabolic tro A linear solar fresnel solar plant can be hybridized with fossil fuel backup to b The absorber tube is simpler and less expensive than that of the parabolic tro

Disadvantages 1

A linear solar fresnel solar plant doesn't produce a fluid temperature as high so its thermal efficiency for conversion of solar power to electricity is lower.

Design and arrangement of mirrors

The linear Fresnel collector concepts uses a number of rows of relatively small one

Axis Tracking mirrors that concentration the radiation on a linear receiver.

As per above pictures How to adjest mirrors and receiver tubes in correct mannar For this we will use ray Trace simulation software will use for optical efficiency si Large number of rays of incide The direction and point of inte

Reflecting ray follows the priciple that the angle of r

Tracking angle Ψ of the ith reflecctor calculated acco Ψ=

(φ - θ)/2

Single Axis tracking about the polar axis approaches with in 4% the radiation avalability o 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(φ)

Angle of incidence @ April 15 (δ) Hour angle (ω) Slope of apture plane(β) Tracking about East-West horizantal Axis

Fresnel mostly convex shaped mirrors for low and me Parabolic concentrators is the unique reflector shape

In this system we will adopted cylindrical mirrors with different cu the Focal length "f" of the mirror,and Tracking Angle

The radius of curvature we are going to impleme

and for focal length the distence from mirror center to

Radius of curvature for mirrors :

ri =

East-West orientation

possibly the most complex tracking. The angle of the mirrors is de During the winter, the mirrors tilt down towards the south,comin (the plane of the sun's motion is co-incident with the plane of the This tracking will likely need to be accomplished by sensors rathe

The North-South orientation is similar to the polar orientation, but may be flat or cylind with the shallowness of the suns angle parallel to the Since we do not wish to tilt the array towards the sou Also, the reflectors move between plus and minus 22. and a total daily loss of the integral of cos (1/2 theta)

One Example Mirror arrangement

Glass mirrors

As far as curvature goes, there are structural advantag there are geometric limitations to a system which mu Our best results for curvature where with 2'x 1' panel about seven inches of unconcentrated light around th image sizes of about 3 inches were achieved with myl

the limits of concentration

1 As light travels down different angles parallel to the a at another angle it will be out of focus. The percentag 2 At twice the focal distance (%100 out of focus), the im 3 In an east-west axis system, the sun moves from 45 d the extra path length of Square root of two (~1.4) in t The best achievable theoretical fix would be to have t This corresponds to a maximum concentration of 3.27 since the sine changes quickly around 45 degrees, gre

A north south axis orientation will experience this distor Examples of Fresnel power plants: 1 2

Novatec Kimberlina

Ausra Liddell power station

Carrizo Energy Solar Farm(CESF http://www.novatec-biosol.eu/index.php?article_id=5 http://www.ausra.com/technology/ Example:

Apture area Average solar radiation for indian conditio Average sunlight available from morning 8 Total Energy out put Aperture area x solar With 65% concentration efficiency the ene

Example:

Water flows inside of receiver tube o passing through the tube.The tube w Inner diameter of tube water velocity Tube wall temperature Inlet water temperature Outlet water temperature Length of tube Bulk mean temperature Properties of water at 80 C

Rynolds number

Heat transfer

Solar fresnel alignment of collectors and Receiver Tube

f single axis, linear solar mirrors to reflect sunlight onto a receiver tube.In that way it is similar to a solar parabolic trough system. however, uses a 'parabola' made up of ten flat mirrors that each rotate to follow the sun,Instead of a more expensive parabolic shaped m e of system allows theCompact Linear Fresnel Solar Mirrors.flat solar mirrors to remain near the ground, avoiding wind loads.

ce steam at 400 C in the absorber tubes. The steam is used directly to drive a turbine in a standard Rankine cycle to produce electricity, uce steam from some other high temperature fluid.

investment and operational costs.Firstly,the flat mirrirs are cheaper and easier to produce then parabolic curved reflectors and so are rea just one or two meters above groud.This means the plant can operate in strong wind and it can use a lightweight,simple collector structur ent use of land,packing more mirrors closer together compared to parabolic through. y have fewer moving parts and they can turn down during the night for protection from sand and to allow for automated cleaning. hnology generate steam directly,which means they do away with the need for expensive and performance-reducing heat exchangers. 60% of costs of a parabolic trough collector per square metre. ed with fossil fuel backup to be used for electrical generation when the sun isn't shining e than that of the parabolic trough system, because multiple solar mirrors reflect solar power to a single absorber tube and the absorber t

e a fluid temperature as high as the parabolic trough or parabolic dish solar concentrators, power to electricity is lower.

ws of relatively small one

linear receiver.

tubes in correct mannar Trace simulation software will use for optical efficiency simulation of the concentrating collector. arge number of rays of incident radiation throughout the system for reflecting surface. he direction and point of intersection of incident ray with the reflecting surface are determine

le that the angle of reflection equals the angle of incidence

or calculated according to Mr.Rabl φ = is the angle between optical axis and the line from focus to reflector. θ = is the incident angle of the sun relative to the aperture normal.

n 4% the radiation avalability of the collector.

1230 h

15-Apr 12.5 705 949 31.9 5.3 150 11.92

LAT w/m^2 w/m^2 C m/s C Deg

105 th day

9.414893 Deg 16.94419

-7.5

9.494661

ut East-West horizantal Axis COS θ = COSδ(COS^2ω + TAN^2δ)^0.5

haped mirrors for low and medium concentrating one axis tracking or stationary collectors. is the unique reflector shape that focuse beam radiation into a single point.How ever the manufacturof parabollic reflector is too expansi

drical mirrors with different curvature.The mirror radius of curvature "ri "depends on nd Tracking Angle

re we are going to implement ,Tracking angle for perpendicular incident radiation (θ = 0)

distence from mirror center to absorber center.

e for mirrors : (2*f)/cos ψ

The angle of the mirrors is determined by the vector towards the sun projected onto the vertical axis running north-south own towards the south,coming up till noon and decreasing again. The severity of this angular adjustment decreases from winter solstice t -incident with the plane of the parabolic trough), and reverses direction during the summer, as the sun rises slightly north and comes sligh ccomplished by sensors rather than formulas.

tion, but may be flat or cylindrical on the ground.Tracking may be as simple as in polar or it may have hidden complications (We don't kno the suns angle parallel to the axis of the collector would be severe in winter if this orientation were laid flat on the ground. tilt the array towards the south for construction cost reasons (same as polar), and wish to collect energy during the winter, The factor E F e between plus and minus 22.5 degrees of tilt from 9am till 3pm. Thus there will be a maximum half angle loss of cosine 22.5 the integral of cos (1/2 theta) from theta =-22.3 to 22.5

8 Rows 4 reflected mirrors wi Primary mirrors are cylindrica Number of rows Number of sets Mirror width Length Mirror spacing Total mirror area approximat incident angle of the sun relat

φ = is the angle between opt θ = is the incident angle of th

Included angle of sun relative

Radius of curvature Mirror 1 2 3 4 5

Note:

"That means Radius

, there are structural advantages to having fewer reflectors, each with a concentration ratio of 5 or so. Although a perfect parabola could tations to a system which must track the sun. Also, we found a perfect parabolic shap difficult to achieve under non-tracking conditions. ature where with 2'x 1' panels of glass, with an image size of just under an inch and a half (concentration ratio of about 20), wit nconcentrated light around the focus (ie: only 75% of the mirror assumed the curve, since the ends, for whatever reason, do not curve). nches were achieved with mylar on thin plywood, but this could not be achieved over the entire length of the focus.

ferent angles parallel to the axis of the concentrator, it travels different distances before reaching the absorber. Thus, if the array is in per e out of focus. The percentage out of focus is inversely proportional to the amount of concentration possible. ce (%100 out of focus), the image is the same size as the width of the reflector. At 1.5 the focal length (%50), the image will be half the w em, the sun 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, Square root of two (~1.4) in the morning and evening would correspond to %40 out of focus or 2.5 times concentration. oretical fix would be to have the system focused perfectly at 22.5 degrees, so that the absorber is too close at noon and too far at 3pm, b aximum concentration 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= %30.5). uickly around 45 degrees, greater ratios could be obtained by sacrificing efficiency at the extremes.

on will experience this distortion less severely due to the fact that the seasonal angular deviation of the sun is much less than its daily va

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

iddell power station

arrizo Energy Solar Farm(CESF) osol.eu/index.php?article_id=5&clang=1 technology/

r radiation for indian conditions ight available from morning 8 am to 4 pm out put Aperture area x solar radiation x hours ncentration efficiency the energy out put

1 750 8 6000 3.9 1423.5

m^2 W/m^2 hours/day Wh/day KWh/day KWh/year

6 3355.638

de of receiver tube of 20 mm diameter and 3 m long at a velocity of 0.03m/s.The the tube.The tube wall is maintained at constant temperature of 160 C.Find heat transfer

emperature temperature

Bulk mean temperature roperties of water at 80 C Density kinamatic viscosity Prandel number Thermal conductivity

ynolds number Thiis Rynolds number value below 2300,this flow is laminar Nusselt Number Nusselt Number hD/K heat transfer coefficent

Heat transfer

20 0.03 160 40 120 3

mm m/s C C C m

80 C 974 kg/m^3 3.64E-07 m^2/s 2.22 6.69E-01 W/Mk 1.65E+03 3.66 122.3721 W/m^2K

1848 W

0.02

c trough system. nsive parabolic shaped mirror, g wind loads.

Absorber area : Aperture area : Gross area:

to produce electricity,

reflectors and so are readily available from manufacturers worldwide. simple collector structure.

omated cleaning. ng heat exchangers.

tube and the absorber tube doesn't need couplings as the receiver tubes for the parabolic trough and parabolic dish systems do, because

to reflector.

304.9 K

Deg

0.991444861 Deg

c reflector is too expansive.

Concentration ratio =

Collector area/Focussed area = normally 26/1

es from winter solstice till equinox, when no angular adjustment is needed ly north and comes slightly south by noon.

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

he winter, The factor E Farm team has shied away from this orientation as well. cosine 22.5

ws 4 reflected mirrors with a noth - south Tracking Axis ary mirrors are cylindrical with different small curvatures.

mirror area approximatly ent angle of the sun relative to the aperture normal.

2.995496019

0.978147601 12.26808714

s the angle between optical axis and the line from focus to reflector. s the incident angle of the sun relative to the aperture normal.

8 4 0.5 4 0.15 64 0

ded angle of sun relative apeture angle ( θ )(perpendicular incident radiation)

dius of curvature of different mirrors φ 6.28 18.26 28.81 37.6 44.71

ψ 3.14 9.13 14.405 18.8 22.355

Focus (f ) 2.5 2.6 2.65 3.2 3.6

Radius of mirror (ri) 5.007517923 5.266724875 5.472032747 6.76068769 7.785087972

at means Radius of mirror curvature mainly depends on the focal length of the mirror and tra

a perfect parabola could have a concentration ratio of 50 or more on-tracking conditions. about 20), wit reason, do not curve).

Thus, if the array is in perfect focus at one angle,

image will be half the width of the reflector.

on and too far at 3pm, but neither as badly as if the system were in focus at noon. f .33/1.08= %30.5).

uch less than its daily variation.

ize appears small

Kwh Kcal

y of 0.03m/s.The water gets heated from 40 C to 120 C.while heat transfer m

the area of absorber the area in which solar radiation enter the collector the area based on outer dimention of collector

ic dish systems do, because the absorber tube is fixed.

m m m m^ 2 Deg

the mirror and tracking angle.