003 g muthu

Presenting Author

G.Muthu

Research scholar

Department of Mechanical Engineering

National Institute of Technology

Tiruchirappalli

Tamil Nadu

Co Authors

Prof. S.Shanmugam

Prof. AR.Veerappan

11-Dec-131 National Institute of Technology Tiruchirappalli, India

Solar Parabolic Dish Thermoelectric

Generator with Acrylic Cover


Introduction

Methodology

Results

Discussion

Conclusions

References

Outline


Introduction

Concentrating solar power (CSP) systems namely

parabolic trough, linear Fresnel reflector, power

tower and parabolic dish can be used effectively to

convert solar energy into heat.

Solar thermal thermoelectric generator is the most

promising option.

Working principle - Seebeck effect.


Seebeck Effect

11-Dec-135

National Institute of Technology Tiruchirappalli, India

Applications of Thermoelectric power

Cooling fans

Thermoelectric generators

Field generators

Firewood generators

Bio-fuel generators

Vehicle exhaust waste heat generators

Waste incineration generator systems


Structure of Thermoelectric Module


Specification of Module

Model name: TEP1-12656-0.6


Properties of Thermoelectric Module

Ref : Thermonamic Electronics (Xiamen) Co.,Ltd.,China.

Material : Bismuth Telluride alloy (Bi2 Te3)

Seebeck coefficient (α ) =190~ 200 10-6 V / K

Electrical Resistivity ()= 0.926 10-5 ~ 0.9615 10-5 Ω- m

Thermal conductivity (K) = 1.2 ~ 1.6 W/mK


Model of solar TEG


Specification of parabolic dish concentrator

Open mouth diameter of dish 3.56 m

Parabolic concentrator surface area 10.53 m2

Height of the parabola 0.7 m

Reflectivity of the concentrator 0.78

Focal distance 1.11 m


Useful energy gained

The useful energy gained (Qu) on the hot side of

TEG


Heat loss coefficient

If the wind flows over the receiver plate surface at

Vm m/sec, the heat loss coefficient due to the wind

hw, is given by (McAdams, 1954).

hw=5.7+3.8Vm


Instantaneous thermal efficiency

The instantaneous thermal efficiency of the

parabolic dish collector is expressed as


Thermoelectric generator equations

The amount of heat removed from cold side (Qc)

and that supplied to hot side (Qh) of the TEG are

Where S=2 N


Properties of Thermoelectric Module

92 10)9905.06.93022224()( avgTTT avgavg

102 10)6279.04.1635112()( avgTTT avgavg

42 10)4131.07.27762605()( avgTTTK avgavg

Thermoelectric properties are computed from the

following expression (Melcor, 2009).


Electric output & TEG Efficiency

The output (Pteg) from TEG is estimated from the

relation

The efficiency of TEG


Overall efficiency

Overall system efficiency (ηoverall ) is computed

from the relations


Receiver plate temperature with solar beam

radiation

Results


250

270

290

310

330

350

370

390

500 600 700 800 900 1000 1100

Rec

eiv

er p

late

tem

per

atu

re (

K)

Solar beam radiation (W/m2)

With cover

Without cover

Instantaneous thermal efficiency of collector

with solar beam radiation


64.0

64.5

65.0

65.5

66.0

66.5

67.0

67.5

68.0

500 600 700 800 900 1000 1100

Inst

anta

neo

us

ther

mal

eff

icie

ncy

o

f p

arab

oli

c

dis

h c

oll

ecto

r (%

)


With cover

Without cover

The output voltage for various solar beam

radiations


0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

500 600 700 800 900 1000 1100

Ou

tpu

t v

olt

age

of

the

syst

em (

Vo

lts)


With cover

Without cover

Output power with solar beam radiation


0

0.5

1

1.5

2

2.5

3

3.5

4

500 600 700 800 900 1000 1100

Ele

ctri

cal

po

wer

ou

tpu

t (w

)


With cover

Without cover

Overall efficiency of the System with solar

beam radiation


0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

500 600 700 800 900 1000 1100

Ov

eral

l ef

fici

ency

of

the

syst

em (

%)


With cover

Without cover

Conclusions

A maximum of 383 K receiver plate temperature was obtainedfor TEG with cover at solar beam radiation of 1050 W/m2. It is1.56% higher than in TEG without cover for the same solar beamradiation.

There is 2.11% improvement in overall efficiency for TEG withcover as compared to that without cover.

The maximum voltage of the thermoelectric module achievedwas 4 volts, which is 10.75% higher than TEG without cover forsame solar beam radiation.

The electrical power output for modified TEG was 2.51% higherthan that of the TEG without cover.


Photographic view - TEG with solar dish


References

[1] Reddy, K.S. and Sendhil Kumar, N. (2008) Combined

laminar natural convection and surface radiation heat

transfer in a modified cavity receiver of solar parabolic

dish, International Journal of Thermal

Sciences, 47, pp.1647–1657.

[2] Sukhatme, S.P. and Nayak, J.K. (2012) Solar energy:

principles of thermal collection and storage, Edition

2, Tata McGraw Hill Publishing Company limited, India.

[3] Shanmugam, S., Eswaramoorthy, M., and

Veerappan, AR. (2011) Mathematical Modeling of

Thermoelectric Generator Driven, Applied Solar

Energy, 47(1), pp31–35.


References

[4] Eswaramoorthy, M. and Shanmugam, S.(2012) Numerical

Model to Compute Heat Loss in Focal Receiver of Solar

Parabolic Dish Thermoelectric Generator, Energy

Sources, Part A: Recovery, Utilization Environmental

Effects, 34, pp 959-965.

[5] Eswaramoorthy, M. (2010) Studies on solar parabolic dish

thermoelectric generator, Ph.D. Thesis, Department of

Mechanical Engineering, National Institute of

Technology, Tiruchirappalli, India.


Thank You