DLSC 2008-2009 Annual Report v31.1 Scope This document describes the thermal energy generated and...

AAnnnnuuaall RReeppoorrtt ffoorr 22000088--22000099

Prepared for:

Natural Resources Ressources naturelles Canada Canada

Prepared by:

Science Applications International Corporation (SAIC Canada)

February 3, 2010 CM002171

PROPRIETARY

Drake Landing Solar Community Energy Report 2008-2009 February 3, 2010

CM002171 i Science Applications International Corporation

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PROPRIETARY

Statement of Limitations

Third Party Use

This report has been prepared for the Town of Okotoks and National Resources Canada. Any uses which a third party makes of this report, any reliance on the report, or decisions based upon the report, are the responsibility of those third parties unless authorized by SAIC Canada to do so. SAIC Canada accepts no responsibility for damages suggested by any unauthorized third party as a result of decisions made or actions taken based upon this report.

Warranty

SAIC Canada makes no representation or warranty with respect to this report other than the work was undertaken by trained professional and technical staff in accordance with generally accepted engineering and scientific practices current at the time the work was performed.

Reliance on Third Party Information

Any information or facts provided by others and referred to or utilized in the preparation of this report was assumed by SAIC Canada to be accurate. The material in this report reflects SAIC Canada's best judgment in light of the information available to it at the time of preparation.


CM002171 ii Science Applications International Corporation

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PROPRIETARY

TABLE OF CONTENTS

Third Party Use....................................................................................................................................... i Warranty ................................................................................................................................................. i Reliance on Third Party Information ....................................................................................................... i

1 Drake Landing Solar Community Energy Overview ..............................................................................5 1.1 Scope.............................................................................................................................................5 1.2 Additional Information ....................................................................................................................5 1.3 Terminology and Standards...........................................................................................................5 1.4 Overview........................................................................................................................................6 1.5 Summary........................................................................................................................................7

2 Performance Reporting..........................................................................................................................8 2.1 Incident Solar Energy ....................................................................................................................8 2.2 Solar Thermal Energy Collected....................................................................................................9

2.2.1 Solar Thermal Energy Collected............................................................................................9 2.2.2 Solar Energy Collection Efficiency.......................................................................................10 2.2.3 Solar Energy Delivered to Short Term Thermal Storage Tanks..........................................10

2.3 Long Term Energy Storage (BTES) ............................................................................................11 2.4 BTES Temperatures ....................................................................................................................13 2.5 Thermal Energy Delivered to HX-2..............................................................................................16 2.6 Energy Delivered to District Loop ................................................................................................17 2.7 Gas Usage...................................................................................................................................19 2.8 Solar Fraction ..............................................................................................................................20 2.9 Solar PV Energy Delivered ..........................................................................................................20 2.10 Fluid Flow Rates ..........................................................................................................................21 2.11 Fluid Properties............................................................................................................................24 2.12 Electrical Energy from Local Utility ..............................................................................................25 2.13 Ambient Temperatures ................................................................................................................25

3 Performance Analysis..........................................................................................................................26 3.1 Solar Collectors ...........................................................................................................................26

3.1.1 Collector Efficiency ..............................................................................................................26 3.1.2 Collector Flow Distribution ...................................................................................................27

3.2 Short Term Thermal Storage Tanks ............................................................................................28 3.3 Heat Exchanger Performance .....................................................................................................28

3.3.1 Heat Exchanger 1- Efficiency ..............................................................................................29 3.3.2 Heat Exchanger 1- Effectiveness ........................................................................................29 3.3.3 Heat Exchanger 2- Efficiency ..............................................................................................29 3.3.4 Heat Exchanger 2- Effectiveness ........................................................................................30

3.4 District Loop.................................................................................................................................30 3.5 Household Heat Meter Readings ................................................................................................32 3.6 TMY Comparison.........................................................................................................................33

APPENDIX A Corrected Summary.........................................................................................................34 APPENDIX B Effectiveness Mathematic Description.............................................................................35 APPENDIX C System Schematic ...........................................................................................................36 APPENDIX D List of Issues ....................................................................................................................37


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PROPRIETARY

LIST OF FIGURES Figure 1-1 System Energy Diagram ........................................................................................................................6 Figure 2-1 Weekly Incident Solar Energy for 2008-2009 ........................................................................................8 Figure 2-2 Weekly Totals of Solar Energy Collected...............................................................................................9 Figure 2-3 Weekly Totals of Solar Energy Injected Into STTS..............................................................................10 Figure 2-4 Weekly BTES Energy Flow ..................................................................................................................11 Figure 2-5: Annual BTES Energy Flow...................................................................................................................12 Figure 2-6 BTES Temperature Sensor locations ..................................................................................................13 Figure 2-7: BTES Core Temperature .....................................................................................................................14 Figure 2-8- BTES Lateral Temperatures ................................................................................................................15 Figure 2-9 Weekly Solar Thermal Energy Delivered to HX-2................................................................................16 Figure 2-10 Weekly Energy Delivered to District Loop..........................................................................................17 Figure 2-11 District Energy Distribution.................................................................................................................18 Figure 2-12 Weekly Totals of Gas Used (GM-1) ...................................................................................................19 Figure 2-13 Weekly PV Energy .............................................................................................................................20 Figure 2-14: Collector Loop ....................................................................................................................................21 Figure 2-15: STTS HX1 ..........................................................................................................................................21 Figure 2-16: BTES Charging ..................................................................................................................................22 Figure 2-17: BTES Discharging..............................................................................................................................22 Figure 2-18: STTS HX2 ..........................................................................................................................................23 Figure 2-19: District Loop .......................................................................................................................................23 Figure 2-20: Glycol pH............................................................................................................................................24 Figure 2-21: Glycol Concentration..........................................................................................................................24 Figure 2-22 Ambient Temperatures.......................................................................................................................25 Figure 3-1: Collector Efficiency Scatter Plot ...........................................................................................................26 Figure 3-2: Collector Efficiency...............................................................................................................................27 Figure 3-3 Block 1 vs. All Blocks ...........................................................................................................................28 Figure 3-4: HX-1 effectiveness ...............................................................................................................................29 Figure 3-5: HX-2 effectiveness ...............................................................................................................................30 Figure 3-6: District loop Temperature Drop............................................................................................................31 Figure 3-7: District Loop Supply Temperature........................................................................................................31 Figure 3-8: Heat Meter Readings ...........................................................................................................................32


CM002171 iv Science Applications International Corporation

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PROPRIETARY

LIST OF TABLES Table 1-1 Summary .................................................................................................................................................7 Table 2-1 Incident Solar Energy for 2008-2009 ......................................................................................................9 Table 2-2 Energy Collected for 2008-2009............................................................................................................10 Table 2-3 Solar Energy Injected to STTS for 2008-2009 ......................................................................................11 Table 2-4 Incident Solar Energy for 2008-2009 ....................................................................................................11 Table 2-5 BTES Core Temperatures for 2008-2009 .............................................................................................14 Table 2-6 BTES Lateral Array 1 Temperatures for 2008-2009 .............................................................................15 Table 2-7 BTES Lateral Array 2 Temperatures for 2008-2009 .............................................................................15 Table 2-8 Solar Thermal Energy Delivered for 2008-2009....................................................................................16 Table 2-9 Thermal Energy Delivered to DHL for 2008-2009.................................................................................17 Table 2-10 Gas Usage for 2008-2009 ...................................................................................................................19 Table 2-11 PV Energy for 2008-2009....................................................................................................................20 Table 3-1: TMY Data Comparison..........................................................................................................................33 Table A-1 Corrected Summary for 2008-2009 ......................................................................................................34


CM002171 5 Science Applications International Corporation

(SAIC Canada)

PROPRIETARY

1 Drake Landing Solar Community Energy Overview

1.1 Scope This document describes the thermal energy generated and used within the Drake Landing Solar Community at Okotoks Alberta. The purpose of this document is to describe the energy inputs and outputs at various points throughout the system; Section 2: Performance Reporting summarizes the energy flow at the key points in the system. The data is presented in the form of annual totals and weekly plots and is based upon data collected during the period of July 2008 to June 2009. The data summarized in Section 2 is analysed and discussed in Section 3: Performance Analysis.

1.2 Additional Information For further background information on the Drake Landing Solar Community please visit the following website: http://www.dlsc.ca

1.3 Terminology and Standards BTES Borehole Thermal Energy Storage FM Flow Meter HX Heat Exchanger PV Photovoltaic SI System International STTS Short Term Thermal Storage TS Temperature Sensor SI units are used throughout this report unless otherwise indicated. The location of data acquisition components (temperature sensors, flow meters etc.) referenced in the text, are shown in a system schematic in APPENDIX C.



(SAIC Canada)

PROPRIETARY

1.4 Overview Figure 1-1depicts the solar energy system, showing the heat flow for the year.

Figure 1-1 System Energy Diagram

Incident Solar Energy

Solar Thermal Collectors

HX-1

Solar Energy Collected

Energy Delivered

to STTS

Energy Delivered to BTES

Energy Extracted

from BTES

Energy Delivered to

HX-2

Solar Energy Delivered to District Loop

HX-2

BTES

STTS

Gas Boilers

Gas Energy

Delivered District Loop

Total Energy

Delivered to District

Loop

13902.0 GJ 4330.3

4390.9 GJ

2713.3 GJ 561.7 GJ

1980.6 GJ 1791.9.

1172.2 GJ

2964.2 GJ

1194.3 GJ



(SAIC Canada)

PROPRIETARY

1.5 Summary Table 1-1 provides a summary for 2008-2009.

Table 1-1 Summary 2008-2009 2007-2008

Total Incident Solar Energy 13902.0 GJ 13321 GJ

Total Solar Energy Collected 4390.9 GJ 4469 GJ

Total Solar Energy Delivered to STTS 4330.3 GJ 4855 GJ

Total Energy Delivered to BTES 2713.3 GJ 2609 GJ

Total Energy Extracted from BTES 561.7 GJ 152 GJ

Total Energy Delivered from STTS to HX-2 1980.6 GJ 2345 GJ

Total Solar Energy Delivered to District Loop 1791.9. GJ 1671 GJ

Natural Gas Energy Used 1194.3 GJ 1574 GJ

Boiler Thermal Energy Delivered to the District Loop 1172.2 GJ 1365 GJ

Total Energy Delivered to District Loop 2964.2 GJ 3035.7 GJ

Average Solar Collector Efficiency 31.6% 34%

Average Efficiency of HX-1 98.6% 92%

Average Efficiency of HX-2 90.4% 71%

Average BTES core temperature 41.4 °C 40 °C

PV energy generated 13.66 GJ 10 GJ

Solar Fraction 60.4% 55%



(SAIC Canada)

PROPRIETARY

2 Performance Reporting This section summarises the energy flow at key locations in the system. The calculations are performed using instantaneous reading as reported every 10 minutes by the data acquisition system. The energy is shown on a weekly basis. Note: In all weekly plots, week 1 is the first week of July 2008.

2.1 Incident Solar Energy Incident solar energy is based on pyranometer irradiance readings integrated over time and over the total area of the solar collectors. (Area is based on 798 collectors with a gross area of 2.87 m² for a total area of 2,290 m².) Figure 2-1 provides weekly incident energy totals for 2008-2009, starting on July 1, 2008. Pyranometer readings show negative values at night. This is a typical issue with pyranometers and is not unexpected. For clarity, the negative readings are considered to be zero. The pyranometer labelled SR-1 is mounted horizontally. The pyranometer labelled SR-2 is mounted at the same slope as the solar collectors (45 degree slope and south facing).

Figure 2-1 Weekly Incident Solar Energy for 2008-2 009

0.0

50.0

100.0

150.0

200.0

250.0

300.0

350.0

400.0

450.0

500.0

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51

Week

Ene

rgy

(GJ)

SR-1 SR-2

Table 2-1 lists a set of values of interest. The energy received for each 10 minute interval during the month is calculated and summed to give the total energy for the month.



(SAIC Canada)

PROPRIETARY

Table 2-1 Incident Solar Energy for 2008-2009

Description SR-1

Horizontal [GJ]

SR-2 Slope [GJ]

Maximum Energy Week 485.5 439.4 Minimum Energy Week 46.4 73.9 Average Weekly Value 217.8 266.4 Annual Total 11379.8 13902.0

2.2 Solar Thermal Energy Collected

2.2.1 Solar Thermal Energy Collected Figure 2-2 shows a weekly plot of the energy collected and sent to HX-1. The STTS tanks were being modified during weeks 39 and 40 therefore no solar energy was collected during that period. During weeks 25 and 26, snow cover prevented solar energy collection.

Figure 2-2 Weekly Totals of Solar Energy Collected

0

20

40

60

80

100

120

140

160

180

200

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51

Week

Ene

rgy

(GJ)



(SAIC Canada)

PROPRIETARY

Table 2-2 Energy Collected for 2008-2009

Description Energy [GJ] Highest Weekly Value 168.9 Lowest Weekly Value -2.6 Average Weekly Value 84.1 Annual Total 4390.9

2.2.2 Solar Energy Collection Efficiency Collection efficiency for the year is the ratio of solar energy collected to solar energy available. 4390.9 GJ Collected 13902.0 GJ Available

Collected Collection Efficiency =

Available = 31.6%

2.2.3 Solar Energy Delivered to Short Term Thermal Storage Tanks Figure 2-3 shows a weekly plot of the energy collected into the STTS tanks from HX-2.

Figure 2-3 Weekly Totals of Solar Energy Injected Into STTS

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200

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51

Week

Ene

rgy

(GJ)



(SAIC Canada)

PROPRIETARY

Table 2-3 Solar Energy Injected to STTS for 2008-2 009

Description Energy [GJ] Highest Weekly Value 165.7 Lowest Weekly Value 0.0 Average Weekly Value 82.9 Annual Total 4330.3

2.3 Long Term Energy Storage (BTES) Figure 2-4 shows the energy sent to the BTES and the energy recovered from the BTES.

Figure 2-4 Weekly BTES Energy Flow

0

20

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200

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51

Week

Ene

rgy

(GJ)

Sent to BTES Extracted From BTES

Table 2-4 Incident Solar Energy for 2008-2009

Description Sent to BTES [GJ]

From BTES [GJ]

Maximum Energy Week 140.9 57.5 Minimum Energy Week 0.0 0.0 Average Weekly Value 51.8 10.8 Annual Total 2713.3 561.7



(SAIC Canada)

PROPRIETARY

Figure 2-5 shows the energy injected into the BTES and energy recovered from the BTES for the first two years of operation.

Figure 2-5: Annual BTES Energy Flow

0

500

1000

1500

2000

2500

3000

2007-2008 2008-2009

Hea

t (G

J)

Delivered

Extracted



(SAIC Canada)

PROPRIETARY

2.4 BTES Temperatures

Figure 2-6 BTES Temperature Sensor locations

Since the temperature sensors in the BTES field (lateral and core) are located on or near the piping, they essentially show the fluid temperature rather than the temperature of the soil between the boreholes. Figure 2-7 shows the temperature reading (TS22-1 and TS-22-7) when fluid flow in the BTES has been off for at least 4 hours. Seasonal variations are evident. These readings probably better represent the actual earth temperature in the core of the BTES.

TS-24-7 TS-24-6 TS-24-5 TS-24-4 TS-24-3 TS-24-2 TS-24-1 TS-23-1 TS-23-2 TS-23-3 TS-23-4 TS-23-5 TS-23-6 TS-23-7

TS-22-1

TS-22-2

TS-22-3

TS-22-4

TS-22-5

TS-22-6

TS-22-7

0.1 m

1.0 m

9.75 m

17.5 m

25.8 m

34.1 m

35.1 m

LLaatteerraall AArrrraayy 11 LLaatteerraall AArrrraayy 22

Depth



(SAIC Canada)

PROPRIETARY

Figure 2-7: BTES Core Temperature

30

35

40

45

50

55

60

65

70Ju

n-08

Jul-0

8

Sep

-08

Oct

-08

Dec

-08

Feb

-09

Mar

-09

May

-09

Jul-0

9

Aug

-09

BT

ES

Cor

e T

empe

ratu

re (

°C)

TS-22-7 Flow On

TS-22-1

TS-22-7

Table 2-5 summarizes BTES ground temperatures measured when flow was off for at least 4 hours.

Table 2-5 BTES Core Temperatures for 2008-2009

Description Depth (m) Min. (°C) Max. (°C)

Average (°C)

TS-22-1 39.8 33.8 58.3 42.3 TS-22-2 42.1 37.4 60.9 45.5 TS-22-3 32.1 33.7 44.2 38.0 TS-22-4 27.0 28.6 51.6 36.7 TS-22-5 43.5 42.1 60.9 48.5 TS-22-7 41.1 28.3 53.0 37.1

Average Value 31.2 54.9 41.4 Note: Some erroneous data was ignored in Table 2-5, specifically TS-22-6. Table 2-6 and Table 2-7 summarize the lateral BTES temperatures measured when the flow was off for at least 4 hours.



(SAIC Canada)

PROPRIETARY

Table 2-6 BTES Lateral Array 1 Temperatures for 20 08-2009

Description Min. (°C) Max. (°C) Average (°C) TS-23-1 (Centre) 27.4 65.9 47.3 TS-23-2 32.3 64.1 45.5 TS-23-3 34.2 61.8 43.6 TS-23-4 31.0 60.3 41.7 TS-23-5 27.9 57.2 39.2 TS-23-6 23.9 54.3 37.0 TS-23-7(Outside Edge) 21.4 51.8 36.2

Table 2-7 BTES Lateral Array 2 Temperatures for 20 08-2009

Description Min. (°C) Max. (°C) Average (°C) TS-24-1 (Centre) 24.8 67.1 47.6 TS-24-2 32.4 64.6 46.2 TS-24-3 33.6 62.2 43.2 TS-24-4 30.7 59.7 41.2 TS-24-5 27.9 56.3 39.1 TS-24-6 22.7 54.3 37.0 TS-24-7(Outside Edge) 19.8 51.5 36.1

As seen in Figure 2-7, the maximum BTES temperature occurs in the month of September and the minimum occurs in the month of March; Figure 2-8 shows an instantaneous BTES lateral temperature profile for both months at a point when the flow was off for at least 4 hours.

Figure 2-8- BTES Lateral Temperatures

BTES Larteral

20

25

30

35

40

45

50

55

60

65

TS

-24-

7

TS

-24-

6

TS

-24-

5

TS

-24-

4

TS

-24-

3

TS

-24-

2

TS

-24-

1

TS

-23-

1

TS

-23-

2

TS

-23-

3

TS

-23-

4

TS

-23-

5

TS

-23-

6

TS

-23-

7

Temperature Sensor

tem

pera

ture

(°C

)

September

March



(SAIC Canada)

PROPRIETARY

2.5 Thermal Energy Delivered to HX-2 Figure 2-9 shows a weekly plot of the energy sent to HX-2 from the STTS tanks. The district loop runs occasionally during the summer months as seen in weeks 1 to 8. It is unclear why no solar energy was delivered during the 44th week (April 28 to May 4).

Figure 2-9 Weekly Solar Thermal Energy Delivered t o HX-2

0

20

40

60

80

100

120

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51

Week

Ene

rgy

(GJ)

Table 2-8 Solar Thermal Energy Delivered for 2008- 2009

Description Energy (GJ) Highest Weekly Value 99.4 Lowest Weekly Value 0.0 Average Weekly Value 38.1 Annual Total 1980.6



(SAIC Canada)

PROPRIETARY

2.6 Energy Delivered to District Loop Figure 2-10 shows a weekly plot of the energy delivered to the district loop. The solar energy is sent to the district loop through HX-2; solar energy calculations are based on readings from TS-23, TS-4 and FM-3. Note: the anomaly in the second week is due to a flow meter instrumentation error; see the July 2008 report for more details.

Figure 2-10 Weekly Energy Delivered to District Lo op

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200

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51

Week

Ene

rgy

(GJ)

Solar Boilers

Table 2-9 Thermal Energy Delivered to DHL for 2008 -2009

Description Solar Energy (GJ)

Boiler Energy (GJ) Total (GJ)

Highest Weekly Value 89.5 158.2 199.1 Lowest Weekly Value -2.2 0.0 3.9 Average Weekly Value 34.4 22.5 57.0 Annual Total 1791.9. 1172.2 2964.2



(SAIC Canada)

PROPRIETARY

The solar energy, shown in Figure 2-10, is delivered from the STTS tanks and may be directly collected from the solar collectors or recovered from the BTES. Figure 2-11 shows the distribution of the energy sent to the district loop by the boiler, direct solar energy and indirect (BTES) energy.

Figure 2-11 District Energy Distribution

0

500

1000

1500

2000

2500

3000

3500

July

08

Aug

ust

08

Sep

tem

ber

08

Oct

ober

08

Nov

embe

r 08

Dec

embe

r 08

Janu

ary

09

Feb

ruar

y 09

Mar

ch 0

9

Apr

il 09

May

09

June

09

Cum

ulat

ive

Hea

t Sup

plie

d to

Dis

trict

Loo

p (G

J)

Boilers

Indirect Solar (BTES)

Direct Solar

39%

19%

42%



(SAIC Canada)

PROPRIETARY

2.7 Gas Usage The natural gas used is based on readings from the gas meter (GM-1) which reports the gas consumption in cubic meters (m³). Gas volume is converted to energy values using and energy content factor of 36.5 MJ/m³.

Figure 2-12 Weekly Totals of Gas Used (GM-1)

0

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160

180

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51

Week

Ene

rgy

(GJ)

Table 2-10 Gas Usage for 2008-2009

Description Usage (m 3) Equivalent Energy (GJ)

Highest Weekly Value 4430.0 161.7 Lowest Weekly Value 0.0 0.0 Average Weekly Value 629.2 23.0 Annual Total 32720.0 1194.3

The boiler efficiency is the amount of energy supplied to the district loop to the amount of energy (gas) input to the boiler. The gas meter resolution (10 m³) may not be small enough to analyse the boiler efficiency on a short term basis. On an annual basis the boiler efficiency is considered accurate. Energy delivered to the district loop: 1172.2GJ. Equivalent gas energy input: 1194.3GJ.

Boiler Energy Delivered Boiler Efficiency =

Gas Energy Input = 98.1%



(SAIC Canada)

PROPRIETARY

2.8 Solar Fraction The solar fraction is the percentage of the solar heat delivered to the total heat delivered to the district loop. Solar Energy Delivered: 1791.9. GJ. Total Energy Delivered: 2964.2 GJ.

Solar Energy Delivered Solar Fraction =

Total Energy Delivered = 60.4%

2.9 Solar PV Energy Delivered Figure 2-13 gives the daily PV energy delivered as 240 VAC power. Little energy was collected during weeks 26 and 27 due to show cover.

Figure 2-13 Weekly PV Energy

0.0

0.1

0.2

0.3

0.4

0.5

0.6

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51

Week

Ene

rgy

(GJ)

Table 2-11 PV Energy for 2008-2009

Description Energy (GJ) Highest Weekly Value 0.48 Lowest Weekly Value 0.00 Average Weekly Value 0.26 Annual Total 13.66



(SAIC Canada)

PROPRIETARY

2.10 Fluid Flow Rates The following figures show a “flow rate cumulative hour” plot (similar to a ‘load curve’) for various flow streams. Each point on the plot is an instantaneous flow rate reading, ignoring ‘no flow’ conditions. These plots show the number of hours in a year above which the flow rate is reported. For example, Figure 2-14 shows that the flow rate in the district loop was above 14 l/s for approximately 1000 hours in the year and above 4 l/s for 1500 hours.

Figure 2-14: Collector Loop

Collector Loop Flow

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6

8

10

12

14

16

18

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Hours

Flow

Rat

e (L

/s)

Figure 2-15: STTS HX1

STTS HX1 Flow

0

2

4

6

8

10

12

14

16

18

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Hours

Flow

Rat

e (L

/s)

Figure 2-14 and Figure 2-15 show that the collector loop and STTS-HX1 loop have identical flow distributions and that they operated at maximum flow for approximately 1000 hours in the year.



(SAIC Canada)

PROPRIETARY

Figure 2-16: BTES Charging

BTES Charging Flow

0

1

2

3

4

5

6

7

0 500 1000 1500 2000 2500 3000 3500

Hours

Flow

Rat

e (L

/s)

Figure 2-17: BTES Discharging

BTES Discharging Flow

0

1

2

3

4

5

6

7

0 500 1000 1500 2000 2500 3000 3500

Hours

Flow

Rat

e (L

/s)

Figure 2-16 shows that when the BTES was charging, the flow is rarely at its maximum; it was above 1 l/s for approximately 1000 out of 3176 hours. When discharging the BTES, Figure 2-17 shows that the flow generally operated higher than when charging. The BTES was discharging for 1840 hours and charging for 3176 hours.



(SAIC Canada)

PROPRIETARY

Figure 2-18: STTS HX2

STTS HX2 Flow

0

1

2

3

4

5

6

7

0 1000 2000 3000 4000 5000 6000 7000 8000 9000

Hours

Flow

Rat

e (L

/s)

Figure 2-19: District Loop

District Loop Flow

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1

2

3

4

5

6

7

0 1000 2000 3000 4000 5000 6000 7000 8000 9000

Hours

Flow

Rat

e (L

/s)

Figure 2-18 shows that the flow which delivers solar energy from the STTS to the district loop operated at maximum for approximately 1500 hours out of 5720 hours of run time. Figure 2-19 shows a different flow curve than the STTS flow; the district loop is controlled by ambient temperature, while solar energy is delivered when available. The district loop was operating for 8060 hours; 92 % of the year.



(SAIC Canada)

PROPRIETARY

2.11 Fluid Properties The following plots show a summary of the results from fluid property tests of the collector loop glycol. Figure 2-20 shows the glycol pH and the reserve alkalinity.

Figure 2-20: Glycol pH

7.55

7.6

7.65

7.7

7.75

7.8

7.85

7.9

7.95

8

8.05

Apr-08

May-08

Jun-08

Jun-08

Jul-08

Aug-08

Sep-08

Oct-08

Oct-08

Nov-08

Dec-08

Jan-09

Feb-09

Mar-09

Mar-09

Apr-09

May-09

Jun-09

pH

0

1

2

3

4

5

6

7

8

9

Res

erve

Alk

alin

ity

pH

Reserve Alkalinity

Figure 2-21shows the glycol concentration of the glycol – water solution.

Figure 2-21: Glycol Concentration

40%

42%

44%

46%

48%

50%

52%

54%

56%

Apr-08

May-08

Jun-08

Jun-08

Jul-08

Aug-08

Sep-08

Oct-08

Oct-08

Nov-08

Dec-08

Jan-09

Feb-09

Mar-09

Mar-09

Apr-09

May-09

Jun-09G

lyco

l Con

cent

ratio

n



(SAIC Canada)

PROPRIETARY

2.12 Electrical Energy from Local Utility The Energy Centre electric meter was inconsistent and operated on and off through out the year. Of the weeks where the electric meter was operational, the minimum and maximum weekly consumptions are 3.0 GJ and 4.6 GJ respectively. Further analysis is required to estimate the actual electric consumption of the energy centre.

2.13 Ambient Temperatures Minimum, maximum, and average daily temperatures for the month are given in Figure 2-22. Values are based on the outside air temperature readings from TS-1, which is mounted on the north facing (shaded) wall of the energy centre.

Figure 2-22 Ambient Temperatures

-30

-20

-10

0

10

20

30

40

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51

Week

Am

bien

t Tem

pera

ture

(°C

)

Max Min Average



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PROPRIETARY

3 Performance Analysis This section analyses the data presented in the section above. A number of diagnostic analyses were performed to determine if the system is performing as expected and to study sources of inefficiencies.

3.1 Solar Collectors

3.1.1 Collector Efficiency Figure 3-1 shows a scatter plot of instantaneous collection efficiency of DLSC as a function of reduced temperature ((Ti– Ta)/ G). Figure 3-2 shows the efficiency curves of two sample collectors which are used at Drake Landing as well as a scatter plot of the measured efficiency. The efficiency curves shown in Figure 3-2 are derived from a series of test performed at the National Solar Test Facility (NSTF) and is a standard method of classifying solar thermal collector performance. The test is performed where the inlet fluid temperature (Ti) is varied to produce the curve. Measures are taken to keep incident irradiation (G), incident angle, atmospheric temperature (Ta), wind speed, mass flow rate and fluid properties constant. In the real system, these parameters are not constant and can change dramatically in a short period of time. Because of these transient effects and the instantaneous measurements, unrealistic values may be calculated. Figure 3-1 shows the ‘unfiltered’ scatter plot of collector efficiency, ignoring negative values, efficiencies above 400% and reduced temperature values above 1.

Figure 3-1: Collector Efficiency Scatter Plot

0%

50%

100%

150%

200%

250%

300%

350%

400%

0.0 0.2 0.4 0.6 0.8 1.0

(Ti-Ta)/G (°C m²/W)

Col

lect

or E

ffic

ien

cy (η

)

Because of the transient nature of the system, there are some data points which can be neglected. As seen in Figure 3-1, instantaneous collector efficiency above 100% is reported; this is most likely caused by a sudden drop in solar irradiation. Neglecting flow rates less than 10 L/s and incident irradiation less than 700 W/m² results in a more representative scatter plot, as shown in Figure 3-2. Also shown in Figure 3-2 is the collector efficiency curve from the NSTF test of a sample collector from DLSC.



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PROPRIETARY

Figure 3-2: Collector Efficiency

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.10

(Ti-Ta)/G (°C m²/W)

Fie

ld C

olle

ctor

Effi

cien

cy (

η)

Field Collector Efficiency (η)

NSTF Efficiency Curve

As seen in Figure 3-2, the collector efficiency measured at DLSC differs slightly from the predicted collector efficiency from the NSTF report. There are some parameters controlled during the collector test that are variable in the field. Wind and the solar incident angle are constant in the NSTF test but vary in the DLSC system. The back of the solar collectors at DLSC are also protected where as they are un-insulated and exposed during the test.

3.1.2 Collector Flow Distribution Collectors – Block 1 vs. All Blocks: The flow distribution through the collectors can be studied by comparing the flow through block 1 (FM-6) and the total flow through all the collectors (FM-1). There are a total of 798 collectors and block 1 has 184 collectors; therefore, the expected percentage of flow rate through block 1 vs. all blocks is 23%. To demonstrate the flow distribution between block 1 and all blocks, the following figure shows a plot of flow meter 1 as a function of flow meter 6. A trend line was fitted to the scatter plot; the slope of the equation is the fraction of flow rate through block 1 to the total collector flow rate. The fraction (slope) shown in Figure 3-3 is approximately 22% which is close to the expected 23%. The plot shows some periodic scatter at low flow rates but the overall trend is stable.



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PROPRIETARY

Figure 3-3 Block 1 vs. All Blocks

y = 0.2176x

0

1

2

3

4

5

0 2 4 6 8 10 12 14 16 18 20

Total Collector Flow (l/s)

Blo

ck 1

Flo

w (

l/s)

Note: Due to the large number of data points, 1/3 of the data is shown; this does not introduce a bias.

3.2 Short Term Thermal Storage Tanks To demonstrate the efficiency of the Short Term Thermal Storage Tanks, the total amount of energy injected into the tanks from the solar collectors and BTES was compared to the total amount of energy extracted from the tanks including energy to the district loop and to the BTES. Energy Delivered to BTES: 2713.3 GJ, Energy Delivered to HX-2: 1980.6 GJ, Total Energy Extracted from STTS: 4693.9 GJ. Solar Energy Delivered to STTS: 4330.3 GJ, Energy Extracted from BTES: 561.7 GJ Total Energy Injected to STTS: 4892.0 GJ.

Total Energy Extracted from STTS STTS Efficiency =

Total Energy Injected to STTS = 95.9%

This means that 198 GJ was measured as lost from the STTS tank.

3.3 Heat Exchanger Performance The heat exchanger performance is demonstrated with two parameters: efficiency and effectiveness. Heat exchanger efficiency simply shows the amount of heat lost in the heat exchanger; a perfectly insulated heat exchanger would have an efficiency of 100%. The efficiency is calculated as a means to check the instrumentation; if an efficiency of over 100% or significantly less than 100% is reported then the instrumentation performance is questioned. The effectiveness of a heat exchanger is a more descriptive parameter which measures heat transfer performance. Heat exchanger effectiveness compares the amount of heat transferred to the “best case



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PROPRIETARY

scenario”. See APPENDIX B for more details on heat exchanger effectiveness. Similar to the collector efficiency analysis, transient effects and instantaneous data measurements cause scatter in heat exchanger effectiveness. Because of this, the effectiveness is calculated and plotted at design flow rates.

3.3.1 Heat Exchanger 1- Efficiency The efficiency of heat exchanger 1 is calculated as follows: Energy Injected to STTS: 4330.3 GJ. Solar Energy Collected: 4390.9 GJ.

Energy Delivered to STTS HX-1 Efficiency =

Solar Energy Collected = 98.6%

Given an efficiency of 98.6%, there is no reason to doubt the instrumentation performance.

3.3.2 Heat Exchanger 1- Effectiveness The effectiveness of HX1 is shown in Figure 3-4 as a function of flow rate. As seen in Figure 2-14 and Figure 2-15, the peak or design flow rate of the collector loop is above 14 l/s. Therefore the effectiveness is shown only when the flow rate on the hot side and cold side of the heat exchanger is above 14 l/s; this incorporates over 6000 data points. Figure 3-4 shows that the effectiveness of HX-1 at design flow reaches a maximum of 78.8% and an average of 66.5%.

Figure 3-4: HX-1 effectiveness

HX-1

y = 0.052x - 0.0998

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

13.5 14 14.5 15 15.5 16

Cold Side Flow Rate (l/s)

Eff

ectiv

enes

s

3.3.3 Heat Exchanger 2- Efficiency The efficiency of heat exchanger 2 is calculated as follows: Solar Energy Delivered to Domestic Loop: 1791.9. GJ. Energy Extracted: 1980.6 GJ.

Solar Energy Delivered to Domestic Loop HX-2 Efficiency =

Energy Extracted = 90.4%



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PROPRIETARY

An efficiency of 90.5 is lower than expected which gives reason to doubt the accuracy of the instrumentation.

3.3.4 Heat Exchanger 2- Effectiveness The effectiveness of HX2 is shown in Figure 3-5 as a function of district loop flow rate. As seen in Figure 2-18, the peak or design flow rate of the STTS-HX2 loop is approximately 5 l/s. Therefore the effectiveness is shown only when the flow rate on the hot side of the heat exchanger is above 5 l/s, this incorporates over 9000 data points. Figure 3-5 shows that effectiveness of HX-1 at design flow reaches a maximum of 90.9% and an average of 74.5%.

Figure 3-5: HX-2 effectiveness

HX-2 y = -0.0444x + 0.9199

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 1 2 3 4 5 6 7

District Loop Flow Rate (l/s)

Eff

ectiv

enes

s

3.4 District Loop To show when heat is in demand, Figure 3-6 shows ambient temperature and the temperature drop (∆T) over the district loop.



(SAIC Canada)

PROPRIETARY

Figure 3-6: District loop Temperature Drop

0

5

10

15

20

25

30

35

-40 -30 -20 -10 0 10 20 30 40

Ambient T

Dis

tric

t Loo

p T

empe

ratu

re D

rop


Figure 3-7: District Loop Supply Temperature

30

35

40

45

50

55

60

65

-50 -40 -30 -20 -10 0 10 20 30 40

Ambient Temperature (°C)

Dis

tric

t Loo

p S

uppl

y Te

mpe

ratu

re (°

C)

Control Signal

Measured Supply Temperature




(SAIC Canada)

PROPRIETARY

Figure 3-6 shows a clear trend of a larger district temperature drop with low ambient temperatures. Figure 3-7 shows the district loop supply temperature increasing as ambient temperature decreases; the trend follows the control signal.

3.5 Household Heat Meter Readings Figure 3-8 shows a running summary of the heat delivered to the district loop (as measured in the energy centre) and the heat meter billing values. As expected, the plot shows the heat meter reading is lower than the measured heat delivered to the district loop; a difference of 478 GJ, a loss of 16.2%, at the last meter reading on June 12, 2009. Some heat loss is expected in the district loop however further investigation is needed to determine if this apparent heat loss meets design expectations.

Figure 3-8: Heat Meter Readings

0

500

1000

1500

2000

2500

3000

3500

July

08

Aug

ust 0

8

Sep

tem

ber

08

Oct

ober

08

Nov

embe

r 08

Dec

embe

r 08

Janu

ary

09

Feb

ruar

y 09

Mar

ch 0

9

Apr

il 09

May

09

June

09

Hea

t Con

sum

ptio

n (G

J)

MetasysEnergy Meters

2949 GJ

2471 GJ



(SAIC Canada)

PROPRIETARY

3.6 TMY Comparison Table 3-1 shows a monthly comparison between measured data at DLSC and the Typical Meteorological Year (TMY) weather file that is used in simulating system performance. Heating and cooling degree day references the average ambient temperature of each day to 18°C (Heating degree day =18- Average temperature)1.

Table 3-1: TMY Data Comparison

Heating Degree

Day Average Temperature

°C Available Solar

Radiation (MJ/m²)

TMY 2008-2009 TMY

Calgary Airport

2008-2009 TMY

2008-2009

July 86 97 16.8 16.5 16.4 709 676 August 99 113 16.1 16.6 16.3 661 626 September 252 244 10.2 11.3 10.3 568 565 October 377 392 5.9 6.7 5.5 560 499 November 648 518 -3.6 2.2 0.7 364 259 December 801 942 -7.9 -10.9 -12.4 300 171 January 812 770 -8.2 -6.2 -8.0 402 326 February 684 738 -6.4 -7.1 -8.4 441 422 March 675 698 -3.8 -4.4 -4.6 600 607 April 412 446 4.3 3.4 3.2 588 600 May 277 271 9.4 9.7 9.7 628 655

June 132 163 14.6 13.3 13.5 617 667

Total 5257 5393 3.9 4.3 3.5 6,437 6,072

% Difference 2.6% 7.8% -10.8% -5.7%

1 The reference temperature used for the heating degree day is equal to that used by Environment Canada http://climate.weatheroffice.ec.gc.ca/climate_normals/climate_info_e.html#11



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PROPRIETARY

APPENDIX A Corrected Summary During the period of March 24th and April 7th, 2009, no solar energy could be collected because the Short Term Storage Tanks were unused due to maintenance. During this time, solar energy could not be collected, stored in the BTES or delivered to the district loop. If the system had been operational during this period, it was estimated that 183Table A-1

Table A-1 Corrected Summary for 2008-2009 Measured Corrected

Total Incident Solar Energy 13902.0 GJ Not Corrected

Total Solar Energy Collected 4390.9 GJ 4565.5 GJ

Total Solar Energy Delivered to STTS 4330.3 GJ 4504.9 GJ

Total Energy Delivered to BTES 2713.3 GJ Not Corrected

Total Energy Extracted from BTES 561.7 GJ Not Corrected

Total Energy Delivered from STTS to HX-2 1980.6 GJ 2134.4 GJ

Total Solar Energy Delivered to District Loop 1791.9. GJ 1945.7 GJ

Natural Gas Energy Used 1194.3 GJ 1045.7 GJ

Boiler Thermal Energy Delivered to the District Loop 1172.2 GJ 1023.62 GJ

Total Energy Delivered to District Loop 2964.2 GJ Not Corrected

Average Solar Collector Efficiency 31.6% Not Corrected

Average Efficiency of HX-1 98.6% 98.6%

Average Efficiency of HX-2 90.4% 91.1%

Average BTES core temperature 41.4 °C Not Corrected

PV energy generated 13.66 GJ Not Corrected

Solar Fraction 60.4% 65.6%



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PROPRIETARY

APPENDIX B Effectiveness Mathematic Description Heat Exchanger Effectiveness is calculated as (actual heat transferred) / (theoretical maximum heat transfer). See the schematic below for the nomenclature of the following equations.

The actual heat transfer rate (Qreal) is calculated as follows:

TcmQ preal ∆= &

Where: m& is the mass flow rate [kg/s],

pc is the specific heat [kJ/kg°C], and

T∆ the change in temperature of the fluid. This can be calculated for either the hot side or cold side fluid (hot side is depicted by subscript h and cold side is depicted by subscript c, as seen in the schematic above). The theoretical maximum heat transfer (Qmax) is calculated as follows:

)()( ,,minmax incinhp TTcmQ −= &

Where:

min)( pcm& is the lowest product of flow rate and specific heat product of the two fluids, and the temperature drop

in this case is the difference between the two inlet temperatures (which corresponds to the largest temperature difference). Given this the effectiveness (ε) is calculated as follows:

)()(

)()(

)()(

)()(

,,min

,,

,,min

,,

max incinhp

outcinccoldp

incinhp

outhinhhotpreal

TTcm

TTcmor

TTcm

TTcm

Q

Q

−−

−−

==&

&

&

&ε

T h,in

T h,out

T cold,out

T cold,in

Heat Exchanger

Cold side Hot side



(SAIC Canada)

PROPRIETARY

APPENDIX C System Schematic



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PROPRIETARY

APPENDIX D List of Issues The following table is a list of monitoring issues as reported in the monthly reports.

ID No. Start Date End Date Description Comments 2008.01 13-Mar-

08 17-Jun-08 Electric utility error A reading of zero electricity used was

indicated for a three month period.

2008.02 17-Jun-08 18-Jun-08 Power outage test A test was performed of the fluid cooler and emergency power system.

2008.03 12-Jul-08 14-Jul-08 Anomaly in delivered solar energy

An instrumentation error resulted in erroneous data reported for the energy delivered to the district loop. The error was traced to FM-3.

2008.04 10-Oct-08 16-Dec-08

Electric utility error A reading of zero electricity used was indicated for a three month period.

2008.05 13-Dec-09

31-Dec-09

Low PV output and collected solar thermal energy The PV output solar collected does not track

the available solar trend in the first half of the month; snow cover is suspected to be the cause.

2009.01 21-Jan-09 22-Jan-09 Data Loss starting at 12:20am to 10:00am the next day.

Based on an outage of the local SonicWALL firewall/ router, there was a loss of data from Metasys into the repository

2009.02 1-Jan-09 10-Jan-09 Low PV output

The PV output does not track the available solar trend in the first half of the month; snow cover is suspected to be the cause.

2009.03 27-Jan-09 27-Jan-09 Glycol release in Energy Centre

A release of glycol just after noon caused several temperature sensors to provide errant readings for about 2 hours. TS's affected included 2-6, 9, 21, 22-1 to 22-6, and 24.

2009.04 7-Feb-09 7-Feb-09 Fluid Cooler Test A fluid cooler test was performed on this date which may have an affect on the system performance.

2009.05 25-Feb-09

25-Feb-09

Updated Pyranometer calibration.

At 15:02, the pyranometer calibration factors, programmed into the DX9100, were changed to the correct numbers. Correction factors are still applied to the solar radiation data to correct for instrumentation error.



(SAIC Canada)

PROPRIETARY

ID No. Start Date End Date Description Comments 2009.06 13-Mar-

09 13-Mar-

09 Test of emergency power system from about 10:00 a.m. to 2:00 p.m.

Should have little impact on data or system performance. P1.2 would run, rather than P1.1

2009.07 19-Mar-09

19-Mar-09

Low temperature Fluid cooler test

A low temperature fluid cooler test was performed on this date which may have a small affect on the system performance.

2009.08 20-Mar-09

20-Mar-09

Fluid Cooler Test A fluid cooler test was performed on this date which may have an affect on the system performance.

2009.09 24-Mar-09

7-Apr-09 STTS Retrofit The STTS tanks were drained for a retrofit. Because of this, solar energy cannot be collected or distributed.

2009.10 19-Mar-09

23-Sep-09

Electric utility error A reading of zero electricity used was indicated for half of the month.

2009.11 14-Apr-09 14-Apr-09 Low Solar Collected A negative reading of solar energy collected was reported on this date.

2009.12 15-Apr-09 15-Apr-09 BTES Core Temperature TS-22-1 and TS-22-2 shows a temperature reading or 605 for one reading.

2009.13 24-Mar-09

20-May-09

Uninsulated HX-1 During the STTS retrofit the insulation on HX1 was removed and has not yet been replaced. This may cause heat loss from the heat exchanger during normal operation.

2009.14 20-May-09

20-May-09

Power outage At 9:00 am, the power was shut down in order to perform some electrical work.

2009.15 1-Jun-09 -- TS-22-2 The sensor is reporting a constant temperature of -50°C

DLSC 2008-2009 Annual Report v31.1 Scope This document describes the thermal energy generated and...

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