Evaluation of Grid Interactive Electric Thermal Storage (GETS) Heaters in Standalone Wind Diesel Systems

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Evaluation of Grid‐Interactive Electric

Thermal Storage (GETS) Heaters in

Standalone Wind‐Diesel Systems

2014 Alaska Wind Integration Workshop

March 21, 2014

Richard Wies

Associate Professor

University of Alaska Fairbanks (UAF) Institute of Northern Engineering (INE)

Co‐Investigators:

Nick Janssen

, Graduate Student, UAF INE

Rorik Peterson

, Associate Professor, UAF INE

This work was supported by:

1) Alaska Energy Authority‐Emerging Energy Technology Fund Round 1

2) U.S. Department of Energy, Office of Science, Basic Energy Sciences, under

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Evaluation of Grid‐Interactive Electric

Thermal Storage (GETS) Heaters in

Standalone Wind‐Diesel Systems

► _{Goals: Use of Wind Energy}

► Space Heating & Storage

► _{Grid Frequency Control}

► _{GETS Controller Testing}

► Steffes 2102 Ratings

► _{Laboratory Test Setup}

► Results: Response to Frequency

► _{Electric‐Thermal Model}

► Voltage & Frequency

Dynamics

► Thermal Model

► _{Conclusions (Take‐Aways)}

Photo Credit: Steffes Corporation

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► _{Electrothermal Space Heating/Storage:}

► _{Excess Wind to Displace Oil Heating}

► _{Masonry Heaters (Steffes Units)}

► On/off control strategies

► Voltage/frequency control

► Secondary (Dump) Load

Use of Excess Wind Energy

30%

50%

20%

Fuel Use in Rural Alaska Villages

Electricity

Space Heating

Transportation

Photo Credit: Dennis Meiners, Intelligent Energy Systems

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Steffes 2102 Heater Ratings



Electric Ratings

Heat Elements: 120 V; 1.33 kW

Blower: 120 V; 30‐100W



Weight

Bricks (16): 176 lbs

Heater: 105 lbs



Storage Capacity

46,062 BTU or 13.5 kWh



Heat Capacity (Bricks)

0.22 BTU/°F*lb



Temperature Rise

1100 °F



Loss of Heat through Insulation

2.4 BTU/°F*h



Heat Delivered on Demand

20,000 BTU/h

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UAF Power Lab Test Setup

(6)

(7)

GETS Controller:

Programmed Frequency Response

(8)

GETS System Response:

f = 60.5 Hz

4

6

8

10

12

14

57

58

59

60

61 Time (s)

F

re

que

nc

y

(H

z)

Frequency of Voltages

Fan

Fbn

Fcn

4

6

8

10

12

14

2

4

6

8

10 Time (s)

RM

S

Cu

rre

nt

(

A

)

RMS Line Currents

IaRMS

IbRMS

IcRMS

(9)

GETS System Response:

Frequency Rise (60 to 65 Hz)

Frequency

Rise

Time to first

response (s)

0.58 Time to

appropriate

response (s)

1.51 Ramp rate

(Hz/s)

8.00

10

10.5

11

11.5

12

12.5

58

60

62

64

66

68

X: 10.03 Y: 60.5

Time (s)

F

reque

nc

y

(H

z)

Frequency of Voltages

X: 9.984 Y: 60.25 X: 9.809 Y: 59.95

Fan

Fbn

Fcn

10

10.5

11

11.5

12

12.5

2

4

6

8

10

12

14

X: 11.54 Y: 6.018

Time (s)

RM

S

Cu

rr

en

t

RMS Line Currents

X: 10.53 Y: 1.745

IaRMS

IbRMS

IcRMS

(10)

GETS System Response:

Frequency Dip (60.5 to 57 Hz)

1

1.5

2

2.5

3

3.5

4

4.5

56

58

60

62

X: 2.16 Y: 60

Time (s)

F

req

uenc

y

(H

z)

Frequency of Voltages

Fan

Fbn

Fcn

1

1.5

2

2.5

3

3.5

4

4.5

0

5

10

15

X: 3.506 Y: 8.832

Time (s)

RM

S

Cu

rr

en

t

RMS Line Currents

IaRMS

IbRMS

IcRMS

Frequency

Dip

Time to first

response (s)

0.49 Time to

appropriate

response (s)

1.35 Ramp rate

(Hz/s)

2.67

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GETS System Response:

Zero & Full ETS Load (Cycling)

4

6

8

10

12

14

16

56

58

60

62 Time (s)

F

req

ue

nc

y

(H

z)

Frequency of Voltages

Fan

Fbn

Fcn

4

6

8

10

12

14

16

0

5

10

15

X: 4.338 Y: 9.53

Time (s)

RM

S

Cu

rr

en

t

RMS Line Currents

X: 3.338 Y: 2.044 X: 13.34 Y: 9.707 X: 12.34 Y: 1.869 X: 7.332 Y: 10.29 X: 6.332 Y: 1.501 X: 10.34 Y: 9.214 X: 9.34 Y: 1.642

IaRMS

IbRMS

IcRMS

(12)

GETS System Response:

¾ & Full ETS Load (Cycling)

2

4

6

8

10

12

55

60

65

70 Time (s)

F

req

uenc

y

(H

z)

Frequency of Voltages

Fan

Fbn

Fcn

2

4

6

8

10

12

2

4

6

8

10

12

X: 10.51 Y: 8.538

R

M

S

C

ur

rent

RMS Line Currents

X: 9.483 Y: 9.314 X: 7.483 Y: 8.062 X: 6.505 Y: 10.02 X: 4.505 Y: 8.349 X: 3.483 Y: 10.37 X: 1.483 Y: 8.393

IaRMS

IbRMS

IcRMS

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GETS System Response:

Switching to Engage ETS Load

2.6

2.7

2.8

2.9

3

3.1

3.2

3.3

3.4

59

60

61

62 Time (s)

F

req

ue

nc

y

(H

z)

Frequency of Voltages

Fan

Fbn

Fcn

2.6

2.7

2.8

2.9

3

3.1

3.2

3.3

3.4

8

9

10

11

X: 2.69 Y: 9.76

Time (s)

RM

S

Cu

rre

nt

RMS Line Currents

X: 2.79 Y: 9.163 X: 2.97 Y: 10.08 X: 3.07 Y: 9.496 X: 3.251 Y: 10.54 X: 3.351 Y: 9.883

IaRMS

IbRMS

IcRMS

Off: ~0.1 sec

On: ~0.2 sec

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GETS System Response:

Switching to Disengage ETS Load

3.2

3.4

3.6

3.8

4

4.2

58.5

59

59.5

60

60.5

61 Time (s)

F

requ

en

cy

(

H

z)

Frequency of Voltages

Fan

Fbn

Fcn

3.2

3.4

3.6

3.8

4

4.2

1

2

3

4

5 RM

S

Curre

nt

X: 3.926_{Y: 4.373} X: 3.608 Y: 1.574 X: 3.507 Y: 4.389 X: 3.407 Y: 1.491 X: 3.29 Y: 4.421 X: 3.19 Y: 1.368 X: 3.708 Y: 4.421 X: 3.826 Y: 1.698

RMS Line Currents

IaRMS

IbRMS

IcRMS

Off: ~0.1 sec

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Summary of Results:

Response of GETS Controller



ETS Load Changes:



Discrete ETS Load Levels: apply or remove based on measured frequency f



Cycled ON & OFF: @ two discrete load levels for 60 Hz  f  60.5 Hz



System Frequency Changes:



Frequency Rise: add load in steps until fully loaded @ 60.5Hz



Frequency Dip: remove load in steps until fully unloaded @ 60Hz



Time Delays:



Delay Time (no ETS load to full ETS load): 1.00 s



Delay Time (¾ ETS load to full ETS load): 2.00 s



Controller Switching Times:



Small (< 1 A) ETS Loads: OFF for 0.10 s; ON for 0.20 s



Medium (≈ 3 A) ETS Loads: OFF for 0.10 s; ON for 0.10 s

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ETS‐Power Systems Integration Laboratory

(PSIL) Model

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0 2 4 6 8 10 12 14 -5 0 5 10 15x 10 4 Time (s) P ow er (W } WTG Real Power No ETS Units 5 Units/Phase 10 Units/Phase 15 Units/Phase 20 Units/Phase 0 2 4 6 8 10 12 14 0.96 0.98 1 1.02 1.04 Time (s) F re que nc y (p u) Bus Frequency No ETS Units 5 Units/Phase 10 Units/Phase 15 Units/Phase 20 Units/Phase 0 2 4 6 8 10 12 14 400 450 500 550 600 Time (s) V olt age (V ) Bus Voltage No ETS Units 5 Units/Phase 10 Units/Phase 15 Units/Phase 20 Units/Phase 0 2 4 6 8 10 12 14 0 10 20 30 40 Time (s) R ot or A ngle (° ) SM Rotor Angle No ETS Units 5 Units/Phase 10 Units/Phase 15 Units/Phase 20 Units/Phase

Zoom-in on next slide

(voltage stability)

75 kW

61.2 Hz

550 V with 15 units

125 kW

Multiple ETS‐PSIL Model Results

(60‐60.5 Hz; 0.1 sec hold)

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8.5 9 9.5 10 10.5 11 11.5 12 12.5 -5 0 5 10 15x 10 4 Time (s) P ow er (W } WTG Real Power No ETS Units 5 Units/Phase 10 Units/Phase 15 Units/Phase 20 Units/Phase 8.5 9 9.5 10 10.5 11 11.5 12 12.5 400 450 500 550 600 V olt ag e (V ) Bus Voltage Time (s) No ETS Units 5 Units/Phase 10 Units/Phase 15 Units/Phase 20 Units/Phase 20 30 40 or An gl e (°) SM Rotor Angle No ETS Units 5 Units/Phase 10 Units/Phase 15 Units/Phase 9.4 9.6 9.8 10 10.2 10.4 10.6 10.8 11 11.2 11.4 0.99 1 1.01 1.02 1.03 F requ enc y (pu) Bus Frequency Time (s) No ETS Units 5 Units/Phase 10 Units/Phase 15 Units/Phase 20 Units/Phase

61.2 Hz

550 V with 15 units

125 kW

65.6 kW

Multiple ETS‐PSIL Model Results

(60‐60.5 Hz; 0.1 sec hold)

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► _{Excess Wind to Electric Heat}

► _{Displace oil heat & storage potential}

► _{Wind‐Diesel System Stability}

► _{GETS could assist with frequency regulation}

► _{Effect on voltage stability with multiple ETS loads}

► _{Further Investigation}

► _{Effect of multiple GETS units coming “ON” at same time}

► _{Distributed control among GETS units}

► _{Thermal characteristics & possible improvements?}

► _{On‐site manufacture of bricks?}

Conclusions (Take Aways)

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Questions?

Contact Info:

Richard Wies, Ph.D., P.E.

Electrical and Computer Engineering

Email: [email protected]

Phone: (907) 474‐7071

‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐

Rorik Peterson, Ph.D.

Mechanical Engineering

University of Alaska Fairbanks

Email: [email protected]

Phone: (907) 474‐5593

The Heat is

ON

in the Arctic!!

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Steffes 2105 Heater Ratings



Electric Ratings

Heat Elements: 240 V; 6.0 kW, 7.5 kW, or 9.0 kW

Blower: 120 V; 30‐100W



Weight

Bricks (40): 440 lbs

Heater: 145 lbs



Storage Capacity

115,155 BTU or 33.75 kWh



Heat Capacity (Bricks)

0.22 BTU/°F*lb



Temperature Rise

1100 °F



Loss of Heat through Insulation

2.4 BTU/°F*h



Heat Delivered on Demand

20,000 BTU/h