Parabolic Concentrated Solar Systems for Heating Applications in Cold Climates

Faezeh Mosallat – Dr. Eric Bibeau

What is happening?

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World oil prices in three cases(2009 dollars per barrel)

(Source: EIA, International Energy Outlook 2011)

World energy consumption by fuel(quadrillion Btu = 1015 Btu = 25 Mtoe)

34%

29%

12%

14% $62 per barrel

$125 per barrel

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What is happening?

BBC news, May 10th, 2013:

Carbon dioxide levels in the atmosphere have broken through a symbolic mark.

Daily measurements of CO2 at a US government agency lab on Hawaii have topped 400 parts per million for the first time.

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Energy policy to improve energy systems

RED

Renewable energy supply

Demand reduction

Efficiency improvement

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How much land to provide the whole world energy demand by solar?

8% conversion efficiency

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Which solar technology?

- www.window.state.tx.us/specialrpt/energy/renewable/images/exhibit10-4 - greenterrafirma.com/images/solar-

trough

- www.energy.siemens.com/nl/pool/hq/power-generation/power-plants/csp - www. Solarpraxis.de\M.Romer

Thigh up to 90°C

Thigh up to 600°C Thigh up to 300°C

Thigh up to 600°C Thigh up to 300°C

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Which solar technology?

Cabrera, F. J., Fernandez-Garcia, A., Silva, R. M. P., Perez-Garcia, M., Use of parabolic trough solar collectors for

solar refrigeration and air-conditioning applications, Renewable and Sustainable Energy Reviews, 2013; 20: 103-118

FPC: flat plate collector, ETC: evacuated tube collector, CPC: compound parabolic concentrator, PTC: parabolic trough collector

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Parabolic solar trough

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Objectives and contributions

• Study and document the operation of a community-based solar

trough collector system in cold Canadian climates.

• Develop a validated numerical system model in Simulink.

• Develop an optimal controller approach to generate, store, and

distribute the energy between different users with various

temperature requirements (tri-generation).

• Optimize revenues and fossil fuel displacement.

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Solar trough facility

• 8 troughs

• South facing

• Tracking

• Heat transfer fluid: Therminol 59

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Solar system simulation

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-C-

E

SOLAR

TROUGH

Solar Trough1

state

ctrl

outlet press.

out

P_el_in

in

info

Pump

in

out

Q_loss

T_buff(°C)

p_loss(bar)

Pipe/supplyin

out

Q_loss

T_buff(°C)

p_loss(bar)

Pipe/return

In1 Out1

Pipe and fittings inside trailer

Mass flow

in

PFin

out

state

overflow

PFout

info

Liquid Tank

in

PFin

out

PFout

Initial conditions:

T = 293.15[K]

p = 60000[Pa]

out1

out2

Qdot

PFout1

PFout2

info

in1

in2

PFin1

PFin2

Heat Exchanger NTU

Weather Data

Get_Input1

[T_out_collector]T_out_collectoru

Collector Pump Controller

Solar trough simulation - Simulink model

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Solar trough simulation - Validation

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Thermal energy generation - Winnipeg

Monthly thermal energy generation by solar facility

Solar radiation

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Thermal energy generation - Winnipeg

Monthly solar efficiency ηs = Qnet / Qsolar

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Displacing revenue - Winnipeg

Monthly revenue obtained from displacing natural gas and Propane with solar thermal considering the same amount of thermal energy produced from solar facility

• Electricity cost: $0.08/kWh

• Natural gas cost: $0.025/kWh

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ORC vs. CPV

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ORC vs. CPV power generation

Time

Collectorsoutlet

temperature (C)

CPV power (kWhe/day)

ORC power (kWhe/day)

July 1st50 144 -

150 110 71

January 1st50 28 -

150 21.5 0.34

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ORC vs. CPV solar electrical efficiency

Time

Collectorsoutlet

temperature (C)

CPV solar electrical efficiency

(%)

ORC solar electrical efficiency

(%)

July 1st50 13.2 -

150 10.7 6.5

January 1st50 13.27 -

150 10.22 0.1

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Tri-generation system

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Control strategy options

• Constant or variable mass flow rate of thermal oil.

• Thermal energy distribution based on electricity, heating and

cooling cost function during the day (for tri-generation).

• Thermal energy distribution based on electricity, heating and

cooling GHG cost function (for tri-generation).

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Conclusions

• Develop a validated sophisticated model of solar trough system to

consider the effect of different parameters on the system

performance.

• Utilize the numerical model to study the effects of cold weather

conditions on the system performance.

• Apply the numerical model results to implement a more practical

economic analysis.

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Acknowledgements

• Dr. Eric Bibeau – Supervisor – University of Manitoba

• Mr. Tom Molinski and Mr. Jeff Blais – Manitoba Hydro

• Mr. Rob Spewak – Red River College

• NSERC/Manitoba Hydro Industrial Research Chair

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