dlsc 2009-2010 annual report v4x1.1 scope this document describes the thermal energy generated and...

AAnnnnuuaall RReeppoorrtt ffoorr 22000099--22001100

Prepared for:

Natural Resources Ressources naturelles Canada Canada

Prepared by:

Science Applications International Corporation (SAIC Canada)

November 2, 2010 CM002171

PROPRIETARY

Drake Landing Solar Community Energy Report 2009-2010 November 2, 2010

CM002171 i Science Applications International Corporation

(SAIC Canada)

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 Heat Exchanger Performance ..................................................................................................... 27 3.2.1 Heat Exchanger 1- Efficiency .............................................................................................. 28 3.2.2 Heat Exchanger 1- Effectiveness ........................................................................................ 28 3.2.3 Heat Exchanger 2- Efficiency .............................................................................................. 28 3.2.4 Heat Exchanger 2- Effectiveness ........................................................................................ 29

3.3 District Loop ................................................................................................................................. 30 3.4 Household Heat Meter Readings ................................................................................................ 31 3.5 TMY Comparison ......................................................................................................................... 32

APPENDIX A Effectiveness Mathematic Description ............................................................................. 34 APPENDIX B System Schematic ........................................................................................................... 35 APPENDIX C List of Issues .................................................................................................................... 36 APPENDIX D System Control Modifications .......................................................................................... 39


CM002171 iii Science Applications International Corporation

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PROPRIETARY

LIST OF FIGURES Figure 1-1 System Energy Diagram ........................................................................................................................6 Figure 2-1 Weekly Incident Solar Energy for 2009-2010 ........................................................................................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 HX-1 ........................................................................................................................................ 21 Figure 2-16: BTES Charging ................................................................................................................................. 22 Figure 2-17: BTES Discharging ............................................................................................................................. 22 Figure 2-18: STTS HX-2 ........................................................................................................................................ 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 .............................................................................................................................. 26 Figure 3-3 Block 1 vs. All Blocks .......................................................................................................................... 27 Figure 3-4: HX-1 effectiveness .............................................................................................................................. 28 Figure 3-5: HX-2 effectiveness .............................................................................................................................. 29 Figure 3-6: District loop Temperature Drop ........................................................................................................... 30 Figure 3-7: District Loop Supply Temperature....................................................................................................... 30 Figure 3-8: Heat Meter Readings .......................................................................................................................... 31


CM002171 iv Science Applications International Corporation

(SAIC Canada)

PROPRIETARY

LIST OF TABLES Table 1-1 Summary .................................................................................................................................................7 Table 2-1 Incident Solar Energy for 2009-2010 ......................................................................................................9 Table 2-2 Energy Collected for 2009-2010........................................................................................................... 10 Table 2-3 Solar Energy Injected to STTS for 2009-2010 ..................................................................................... 11 Table 2-4 BTES Energy for 2009-2010 ................................................................................................................ 11 Table 2-5 BTES Core Temperatures for 2009-2010 ............................................................................................ 14 Table 2-6 BTES Lateral Array 1 Temperatures for 2009-2010 ............................................................................ 15 Table 2-7 BTES Lateral Array 2 Temperatures for 2009-2010 ............................................................................ 15 Table 2-8 Solar Thermal Energy Delivered for 2009-2010 ................................................................................... 16 Table 2-9 Thermal Energy Delivered to DHL for 2009-2010 ................................................................................ 17 Table 2-10 Gas Usage for 2009-2010 .................................................................................................................. 19 Table 2-11 PV Energy for 2009-2010 ................................................................................................................... 20 Table 3-1: TMY Annual Heating Degree Comparison ........................................................................................... 32 Table 3-2: TMY Annual Solar Irradiation Comparison ........................................................................................... 33 Table B-1 – System Control Modifications ............................................................................................................ 39


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 in 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 2009 to June 2010. 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 the data acquisition components (temperature sensors, flow meters etc.) referenced in the text, are shown in a system schematic in APPENDIX B.



(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

12709.1 GJ 4042.6

4274.5 GJ

2499.4 GJ 863.7 GJ

2555.5. 2026.1.

519.5 GJ

2545.1 GJ

543.6 GJ



(SAIC Canada)

PROPRIETARY

1.5 Summary Table 1-1 provides a summary for 2009-2010.

Table 1-1 Summary 2009-2010 2008-2009 2007-2008

Total Incident Solar Energy 12709.1 GJ 13902.0 GJ 13321 GJ

Total Solar Energy Collected 4274.5 GJ 4390.9 GJ 4469 GJ

Total Solar Energy Delivered to STTS 4042.6 GJ 4330.3 GJ 4855 GJ

Total Energy Delivered to BTES 2499.4 GJ 2713.3 GJ 2609 GJ

Total Energy Extracted from BTES 863.7 GJ 561.7 GJ 152 GJ

Total Energy Delivered from STTS to HX-2 2555.5. GJ 1980.6 GJ 2345 GJ

Total Solar Energy Delivered to District Loop

2026.1. GJ 1791.9 GJ 1671GJ

Natural Gas Energy Used 543.6 GJ 1194.3 GJ 1574 GJ

Boiler Thermal Energy Delivered to the District Loop

519.5 GJ 1172.2 GJ 1365 GJ

Total Energy Delivered to District Loop 2545.1 GJ 2964.2 GJ 3035.7 GJ

Average Solar Collector Efficiency 33.6% 31.6% 34%

Average Efficiency of HX-1 94.6% 98.6% 92%

Average Efficiency of HX-2 79.3% 90.4% 71%

Average BTES core temperature Error! Reference source not found.

°C 41.4 °C

40 °C

PV energy generated 12.81 GJ 13.66 GJ 10 GJ

Solar Fraction 79.6% 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 readings 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 2009

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 2009-2010, starting on July 1, 2009. 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 2009-2010

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SR-1 SR-2



(SAIC Canada)

PROPRIETARY

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 year.

Table 2-1 Incident Solar Energy for 2009-2010

Description SR-1

Horizontal [GJ]

SR-2 Slope [GJ]

Maximum Energy Week 440.2 412.8 Minimum Energy Week 48.0 73.7 Average Weekly Value 203.4 243.1 Annual Total 10647.6 12709.1

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 and Table 2-2 shows an annual summary of the collected energy.

Figure 2-2 Weekly Totals of Solar Energy Collected

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(SAIC Canada)

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Table 2-2 Energy Collected for 2009-2010

Description Energy [GJ] Highest Weekly Value 159.0 Lowest Weekly Value 5.4 Average Weekly Value 81.7 Annual Total 4274.5

2.2.2 Solar Energy Collection Efficiency Collection efficiency for the year is the ratio of solar energy collected to solar energy available. 4274.5 GJ Collected 12709.1 GJ Available

Collection Efficiency = Collected

= 33.6% Available

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 and Table 2-3 shows an annual summary of the solar energy sent to the STTS.

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

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(SAIC Canada)

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Table 2-3 Solar Energy Injected to STTS for 2009-2010

Description Energy [GJ] Highest Weekly Value 156.1 Lowest Weekly Value 5.7 Average Weekly Value 77.3 Annual Total 4042.6

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

Figure 2-4 Weekly BTES Energy Flow

Table 2-4 BTES Energy for 2009-2010

Description Sent to BTES [GJ]

From BTES [GJ]

Maximum Energy Week 134.8 78.6 Minimum Energy Week 0.0 0.0 Average Weekly Value 47.7 16.6 Annual Total 2499.4 863.7

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Sent to BTES Extracted From BTES



(SAIC Canada)

PROPRIETARY

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

Figure 2-5: Annual BTES Energy Flow

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Ene

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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. These readings probably better represent the actual earth temperature in the core of the BTES. Seasonal variations are evident.

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

Error! Reference source not found. summarizes BTES core temperatures measured when flow was off for at least 4 hours.

Table 2-5 BTES Core Temperatures for 2009-2010

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

(°C) TS-22-1 39.8 62.9 37.3 48.5 TS-22-2 42.1 -50.0 -50.0 -50.0 TS-22-3 32.1 43.6 6.3 29.4 TS-22-4 27.0 51.3 -15.6 9.2 TS-22-5 43.5 67.8 44.9 56.2 TS-22-7 41.1 62.1 42.0 50.9

Average 2009-2010 64.3 41.4 51.9 Average 2008-2009 31.2 54.9 41.4

Note: Some erroneous data was ignored in Error! Reference source not found.: TS-22-6 was not reported since it failed in 2008, TS-22-2, TS-22-3 and TS-22-4 have been reporting erroneous data since the summer of 2009. The failing sensors were ignored when calculating average values in 2009-2010.

25

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70Ju

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(°C

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BTES Core Temperature

TS-22-1

TS-22-7



(SAIC Canada)

PROPRIETARY

Table 2-6 and Table 2-7 summarize the lateral BTES temperatures measured when the flow was off for at least 4 hours.

Table 2-6 BTES Lateral Array 1 Temperatures for 2009-2010

Description Min. (°C) Max. (°C) Average (°C) TS-23-1 (Centre) 39.3 71.9 52.5 TS-23-2 37.8 70.6 51.1 TS-23-3 36.0 68.9 49.2 TS-23-4 34.1 67.4 46.8 TS-23-5 32.5 64.2 43.5 TS-23-6 31.4 61.8 40.8 TS-23-7(Outside Edge) 30.7 59.2 39.6

Table 2-7 BTES Lateral Array 2 Temperatures for 2009-2010

Description Min. (°C) Max. (°C) Average (°C) TS-24-1 (Centre) 38.6 72.3 52.4 TS-24-2 37.1 70.9 51.2 TS-24-3 -8.5 68.9 44.8 TS-24-4 33.8 66.9 45.9 TS-24-5 32.4 63.8 43.3 TS-24-6 31.4 62.1 40.7 TS-24-7(Outside Edge) 30.8 58.8 39.3

As seen in Figure 2-7, the maximum BTES temperature occurs in the month of September and the minimum occurs in the month of February; 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

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mp

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(°C

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BTES Lateral

September 2009

February 2010



(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. In the 26th and 27th week of the year (December – January) there was little solar energy delivered to the district loop partly due to a failure of P4 during this period.

Figure 2-9 Weekly Solar Thermal Energy Delivered to HX-2

Table 2-8 Solar Thermal Energy Delivered for 2009-2010

Description Energy (GJ) Highest Weekly Value 113.3 Lowest Weekly Value -0.1 Average Weekly Value 49.1 Annual Total 2555.5.

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(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.

Figure 2-10 Weekly Energy Delivered to District Loop

Table 2-9 Thermal Energy Delivered to DHL for 2009-2010

Description Solar Energy (GJ) Boiler

Energy (GJ) Total (GJ)

Highest Weekly Value 91.1 138.8 182.5 Lowest Weekly Value -7.4 0.0 3.1 Average Weekly Value 39.0 10.0 48.9 Annual Total 2026.1. 519.5 2545.1

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Solar Boilers



(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

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tric

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oo

p (

GJ) Boilers

Indirect Solar (BTES)Direct Solar

20%

34%

46%



(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 an energy content factor of 36.5 MJ/m³.

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

Table 2-10 Gas Usage for 2009-2010

Description Usage (m3) Equivalent Energy (GJ) Highest Weekly Value 3730.0 136.1 Lowest Weekly Value 0.0 0.0 Average Weekly Value 271.2 9.9 Annual Total 14100.0 543.6

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: 519.5GJ. Equivalent gas energy input: 543.6GJ.

Boiler Efficiency = Boiler Energy Delivered

= 95.6% Gas Energy Input

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(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: 2026.1. GJ. Total Energy Delivered: 2545.1 GJ.

Solar Fraction = Solar Energy Delivered

= 79.6% Total Energy Delivered

2.9 Solar PV Energy Delivered Figure 2-13 gives the daily PV energy delivered as 240 VAC power.

Figure 2-13 Weekly PV Energy

Table 2-11 PV Energy for 2009-2010

Description Energy (GJ) Highest Weekly Value 0.44 Lowest Weekly Value 0.03 Average Weekly Value 0.24 Annual Total 12.81

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(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. As an 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. The plots show the curves for the past two years.

Figure 2-14: Collector Loop

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2008 - 20092009 - 2010



(SAIC Canada)

PROPRIETARY

Figure 2-15: STTS HX-1

Figure 2-14 and

Figure 2-15 show that the collector loop and STTS-HX-1 loop have similar flow distributions and that they operated at maximum flow for approximately 1000 hours in the year. In the collector loop cumulative flow plot there is a flow bias at 8 l/s which is not evident in the STTS – HX-1 plot. This bias corresponds to start-up conditions where the glycol pumps operate at 50% while bypassing the heat exchanger. The plots show that there was little change from the previous year.

Figure 2-16: BTES Charging

Figure 2-17: BTES Discharging

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(SAIC Canada)

PROPRIETARY

Figure 2-16 shows that when the BTES was charging, the flow is rarely at its maximum; it was above 2.9 l/s for approximately 4050 hours. Figure 2-17 shows that the flow generally operated longer in throughout the year when charging as compared to discharging. The BTES was discharging for 1840 hours and charging for 4050 hours. The plots show that the flow rate this year as compared to last is slightly lower.

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(SAIC Canada)

PROPRIETARY

Figure 2-18: STTS HX-2

Figure 2-19: District Loop

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(SAIC Canada)

PROPRIETARY

Figure 2-18 shows that the flow which delivers solar energy from the STTS to the district loop operated at maximum for approximately 8oo hours out of 5720 hours of run time. The difference between this year and last was caused by build up in HX-2 and the P-4 failure. 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.

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

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

Figure 2-21: Glycol Concentration

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Apr-08

May-08

Jun-08Jul-08A

ug-08S

ep-08O

ct-08N

ov-08D

ec-08Jan-09F

eb-09M

ar-09A

pr-09M

ay-09Jun-09Jul-09A

ug-09S

ep-09O

ct-09N

ov-09D

ec-09Jan-10F

eb-10M

ar-10A

pr-10M

ay-10Jun-10Jul-10A

ug-10S

ep-10O

ct-10

Res

erve

Alk

alin

ity

pH

pH and Reserve Alkalinity

pH Reserve Alkalinity



(SAIC Canada)

PROPRIETARY

2.12 Electrical Energy from Local Utility The Energy Centre electric meter was inconsistent and operated on and off throughout the year. In the weeks where the electric meter was operational, the maximum weekly consumption was 5.4 GJ. 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.

40%

42%

44%

46%

48%

50%

52%

54%

56%

Mar-08

Apr-08

May-08

Jun-08Jul-08A

ug-08S

ep-08O

ct-08N

ov-08D

ec-08Jan-09F

eb-09M

ar-09A

pr-09M

ay-09Jun-09Jul-09A

ug-09S

ep-09O

ct-09N

ov-09D

ec-09Jan-10F

eb-10M

ar-10A

pr-10M

ay-10Jun-10Jul-10A

ug-10S

ep-10O

ct-10

Gly

col C

on

cen

trat

ion

Glycol Concentration



(SAIC Canada)

PROPRIETARY

Figure 2-22 Ambient Temperatures

-30

-20

-10

0

10

20

30

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

Am

bie

nt

Tem

per

atu

re (

°C)

Week

Max Min Average



(SAIC Canada)

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 filtered scatter plot of instantaneous collection efficiency of DLSC as a function of reduced temperature ((Ti– Ta)/ G). The plot also shows the efficiency curve of a sample collector which is used at Drake Landing as well as the scatter plot of the measured efficiency. The efficiency curve shown in Figure 3-1 is derived from a series of tests 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 measured. Because of the transient nature of the system, there are some data points which were neglected. The efficiency plot in Figure 3-1 neglects flow rates less than 10 L/s and includes irradiation measurements between 700 and 1000 W/m². The NSFT test also maintains a constant incident angle; this is accounted for by filtering the data to include only measurements taken between 11:00 and 13:00 when the incident angle is closer to test conditions. Some transient measurements were also accounted for by only including 30 minutes or more of consecutive measurements which meet the criteria described above. The first and last measurements in each series were also ignored.

Figure 3-1: Collector Efficiency

As seen in Figure 3-1, the collector efficiency measured at DLSC differs slightly from the predicted collector efficiency from the NSTF report. Wind is constant in the NSTF test but vary in the DLSC system. The back of the solar collectors at DLSC are also protected where while they are un-insulated and exposed during the test.

y = -3.3163x + 0.631

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0.00 0.02 0.04 0.06 0.08 0.10

Mea

sure

d E

ffic

ien

cy (η

)

(Ti-Ta)/G (°C m²/W)

Collector EfficiencyMeasured Efficiency (η)

NSTF Efficiency Curve



(SAIC Canada)

PROPRIETARY

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 3-2 is approximately 21.4% which is close to the expected 23%. The plot shows some periodic scatter at low flow rates but the overall trend is stable.

Figure 3-2 Block 1 vs. All Blocks

3.2 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 scenario”. See APPENDIX A 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.

y = 0.214x

0.0

1.0

2.0

3.0

4.0

0 2 4 6 8 10 12 14 16 18

Blo

ck 1

Flo

w (l

/s)

Total Collector Flow (l/s)



(SAIC Canada)

PROPRIETARY

3.2.1 Heat Exchanger 1- Efficiency The efficiency of heat exchanger 1 is calculated as follows: Energy delivered to STTS: 4042.6 GJ. Solar Energy Collected: 4274.5 GJ.

HX-1 Efficiency = Energy Delivered to STTS

= 94.6% Solar Energy Collected

3.2.2 Heat Exchanger 1- Effectiveness The effectiveness of HX-1 is shown in Figure 3-3 as a function of flow rate. The effectiveness is shown only when the flow rate on the hot side and cold side of the heat exchanger is above 12.5 l/s.

Figure 3-3: HX-1 effectiveness

3.2.3 Heat Exchanger 2- Efficiency The efficiency of heat exchanger 2 is calculated as follows: Solar Energy Delivered to District Loop: 2026.1. GJ. Energy Extracted: 2555.5. GJ.

HX-2 Efficiency = Solar Energy Delivered to Domestic Loop

= 79.3% Energy Extracted

An efficiency of 79.3 is lower than expected which gives reason to doubt the accuracy of the instrumentation.

y = -0.008x + 0.8655

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

12 12.5 13 13.5 14 14.5 15 15.5 16

Eff

ecti

ven

ess

Cold Side Flow Rate (l/s)

HX-1



(SAIC Canada)

PROPRIETARY

3.2.4 Heat Exchanger 2- Effectiveness The effectiveness of HX-2 is shown in Figure 3-4 as a function of district loop flow rate. The effectiveness is shown only when the flow rate on the hot side of the heat exchanger is above 5 l/s.

Figure 3-4: HX-2 effectiveness

y = -0.0163x + 0.9371

0

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0.7

0.8

0.9

1

0 1 2 3 4 5 6 7

Eff

ecti

ven

ess

District Loop Flow Rate (l/s)

HX-2



(SAIC Canada)

PROPRIETARY

3.3 District Loop To show when heat is in demand, Figure 3-5 shows ambient temperature and the temperature drop (∆T) over the district loop.

Figure 3-5: District loop Temperature Drop

Figure 3-6: District Loop Supply Temperature

0

5

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25

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35

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

Dis

tric

t Lo

op

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re D

rop

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tric

t Lo

op

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ly T

emp

erat

ure

(°C

)

Ambient Temperature (°C)

Control Signal

Measured Supply Temperature



(SAIC Canada)

PROPRIETARY

Figure 3-5 shows a clear trend of a larger district temperature drop with low ambient temperatures. Figure 3-6 shows the district loop supply temperature increasing as ambient temperature decreases; the trend follows the control signal. It is also evident from the measured supply temperature plot that the district loop controls were changed at a point during the year.

3.4 Household Heat Meter Readings Figure 3-7 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 131.1 GJ, a loss of 5.1%, at the last meter reading on June 6, 2010. In the previous year there was a loss of 16.2%, suggesting that a change in controls to lower the district loop supply temperature (see APPENDIX D) reduced heat losses.

Figure 3-7: Heat Meter Readings

0

500

1000

1500

2000

2500

3000

July

09

Aug

ust 0

9

Sep

tem

ber

09

Oct

ober

09

Nov

embe

r 09

Dec

embe

r 09

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ary

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ruar

y 10

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ch 1

0

Apr

il 10

May

10

June

10

July

10

Hea

t Con

sum

ptio

n (G

J)

MetasysEnergy Meters 2527.7 GJ

2396.6 GJ



(SAIC Canada)

PROPRIETARY

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

Table 3-1: TMY Annual Heating Degree Comparison

Heating Degree Day

CWEC

TS-1

2007-2008 2008-2009 2009-2010 July 86 38 97 90 August 99 142 113 128 September 252 265 244 169 October 377 389 392 517 November 648 608 518 493 December 801 834 942 965 January 812 781 770 742 February 684 710 738 631 March 675 554 698 464 April 412 529 446 395 May 277 258 271 322 June 132 167 163 153 Total 5257 5274 5393 5069

% Difference TMY 0.0% 0.3% 2.5% -3.6%

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



(SAIC Canada)

PROPRIETARY

Table 3-2 is a monthly summary of the available solar energy on a horizontal surface. The solar irradiation measured at DLSC from the horizontal pyranometer (SR-1) is compared to the Canadian Weather for Energy Calculations (CWEC) solar irradiation values.

Table 3-2: TMY Annual Solar Irradiation Comparison

Available Solar Energy (MJ/m²) CWEC SR-1

Month 2007-2008 2008-2009 2009-2010

July 753 767 691 704 August 608 528 569 548

September 421 405 399 470

October 307 262 266 209

November 163 145 125 153

December 118 104 99 112

January 147 132 152 121

February 227 225 251 219

March 396 358 445 364

April 508 502 548 514

May 647 556 678 575

June 679 644 741 659

Total 4,974 4,629 4,963 4,649

% Difference CWEC 0.0% -6.9% -0.2% -6.5%



(SAIC Canada)

PROPRIETARY

APPENDIX A 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 B System Schematic



(SAIC Canada)

PROPRIETARY

APPENDIX C 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

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

2009.16 1-Sep-09 1-Jan-10 TS-22-3. TS-22-4 Both sensors are reporting questionable temperature values.

2009.17 30-Sep-09 30-Sep-09 Temperature Sensor Calibration

Johnson controls performed a calibration of the monitoring system; components calibrated include temperature sensors and flow meters.

2009.18 1-Nov-09 30-Nov-09 HX-2 The monthly efficiency of HX-2 is reported to be 78.9%.

2009.19 23-Dec-09 4-Jan-10 P-4 failure Due to a failure of pump 4, solar energy could not be delivered to the district loop. All collected solar energy was either stored in the STTS or sent to the BTES during the pump down time. The excess heat supplied to the BTES may be recovered when the pump comes back online.

2009.20 1-Dec-09 31-Dec-09 HX-2 The monthly efficiency of HX-2 is reported to be 71.2%. This includes small negative energy flows due to down time of P4; neglecting P4 downtime, the HX2 efficiency is 74.1%.

2010.01 1-Sep-09 -- TS-22-3. TS-22-4 Both sensors are reporting questionable temperature values. TS-22-4 is now reporting negative temperature in the BTES core.

2010.02 19-Jan-10 19-Jan-10 Controls Adjustment At 13:07, The district loop temperature control algorithm was changed. The district loop supply temperature (Tds) is controlled based on ambient (Tamb) temperature. As of Jan 19, the algorithm is as follows: For Tamb => -2.5°C, Tds = 38°C For Tamb =< -40°C, Tds = 55°C

2010.03 18-Jan-10 18-Jan-10 TS-24, TS-25 Temperature sensors TS-24 (District loop HX2 outlet) and TS-25 (Boiler outlet) were replaced on this date.



(SAIC Canada)

PROPRIETARY

ID No. Start Date End Date Description Comments

2010.04 18-Jan-10 18-Jan-10 TS-23 TS-23 reported a district loop return temperature of 605°C for two readings (20 min) at starting at 14:40. TS-24, and TS-25 were replaced on the same date which may be the cause of the erroneous data. Correcting for the error, it was estimated that 299.4 GJ of solar energy and a total of 433.8 GJ of energy was delivered to the district loop. The result is a solar fraction of 69.0 % (from 68.9).

2010.05 1-Feb-10 28-Feb-10 TS-5 TS-5 has periodically reported erroneous readings. The effect is not evident in the daily energy values.

2010.06 1-Feb-10 28-Feb-10 P-4 P-4 was oscillating during low district heat demand. A check valve, which caused the oscillations, has been removed. With the removal of the check valve, there is some thermal siphoning; a control valve is being installed on March 5th. The pump oscillations are not evident in the data.

2010.07 1-Mar-10 1-Mar-10 TS-5 At 2:30 pm on this date, TS-5 was replaced; the work lasted for 30 minutes. The work caused an inaccurate reading (of 605°C) for 3 time steps. Corrected values were estimated using linear interpolation.

2010.08 17-Mar-10 17-Mar-10 Boiler During maintenance on this date, the boiler was run for 30 min.

2010.09 29-Mar-10 18-Apr-10 Electric Meter The electric meter has stopped working again starting at 16:10 on March 29, 2010.

2010.10 22-Apr-10 30-Apr-10 Boiler Control issues were causing the boiler to run unnecessarily so it was manually turned off.

2010.11 29-Apr-10 3-May-10 FM-4 Changes made to Metasys data trends caused problems in the data export. The result is 7 hours of lost FM-4 data on May 3 starting at 00:30. The missing data has been recreated using data from FM3, temperature sensors on HX-2.

2010.12 11-May-10 11-May-10 On May 11 a file-system error stopped the Metasys export scheduler from operating correctly. Starting at 12:30 am, 8 hours of drake landing monitoring data was lost, excluding FM-3 and FM-4. Corrections were made for key components used in energy calculations. The corrections were based on temperature data from external sources and the un-lost flow rates.



(SAIC Canada)

PROPRIETARY

ID No. Start Date End Date Description Comments

2010.13 24-May-10 -- TS-24-3 One of the BTES radial temperature sensor (TS-24-3) is reporting erroneous temperature values.

2010.14 29-May-10 29-May-10 The BTES charging/discharging controls were modified as described in Appendix B.

2010.15 6-Jun-10 18-Jul-10 Electric Meter EPM-1 has not reported electric consumption since June 6, 2010. The likely cause is that the electric meter has been reset. The problem was resolved on August 18.



(SAIC Canada)

PROPRIETARY

APPENDIX D System Control Modifications

Table D-1 – System Control Modifications

Date Description of Changes 11-Dec-09 The district loop set point temperature was modified from:

For Tamb => 5°C, Tds = 38°C, For Tamb =< -40°C, Tds = 67°C to:

Tamb => 0°C, Tds = 38°C, For Tamb =< -40°C, Tds = 5 8°C 19-Jan-01 The distict loop set point temperature was modified to:

Tamb => -2.5°C, Tds = 37°C, For Tamb =< -40°C, Tds = 55°C 29-May-10 Previously, if the hot temperature entering the BTES (TS13) is 2°C above cold

temperature exiting the BTES (TS14) then the pump runs until the difference is less than 1°C. This was changed so that TS13 must be 5 a bove TS14 to start and it stops if

the difference drops to less than 3.

dlsc 2009-2010 annual report v4x1.1 scope this document describes the thermal energy generated and...

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