annual report for 2010-2011 - drake landing solar communitybased on sr-1, the global horizontal...

AAnnnnuuaall RReeppoorrtt ffoorr 22001100--22001111

Prepared for:

Natural Resources Ressources naturelles Canada Canada

Prepared by:

Science Applications International Corporation (SAIC Canada)

February 2012 CM002171

PROPRIETARY

Drake Landing Solar Community Energy Report 2010-2011 February 2012

CM002171 i Science Applications International Corporation

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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.


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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 .......................................................................................................................... 9 2.1 Incident Solar Energy .................................................................................................................... 9 2.2 Solar Thermal Energy Collected .................................................................................................. 10

2.2.1 Solar Thermal Energy Collected .......................................................................................... 10 2.2.2 Solar Energy Collection Efficiency ....................................................................................... 11 2.2.3 Solar Energy Delivered to Short Term Thermal Storage Tanks .......................................... 11

2.3 Long Term Energy Storage (BTES) ............................................................................................ 13 2.4 BTES Temperatures .................................................................................................................... 15 2.5 Thermal Energy Delivered to HX-2 .............................................................................................. 19 2.6 Energy Delivered to District Loop ................................................................................................ 20 2.7 Gas Usage ................................................................................................................................... 23 2.8 Solar Fraction .............................................................................................................................. 24 2.9 Solar PV Energy Delivered .......................................................................................................... 24 2.10 Fluid Flow Rates .......................................................................................................................... 25 2.11 Fluid Properties ............................................................................................................................ 29 2.12 Electrical Energy from Local Utility .............................................................................................. 30 2.13 Ambient Temperatures ................................................................................................................ 31

3 Performance Analysis .......................................................................................................................... 32 3.1 Solar Collectors ........................................................................................................................... 32

3.1.1 Collector Efficiency .............................................................................................................. 32 3.1.2 Collector Flow Distribution ................................................................................................... 33

3.2 Heat Exchanger Performance ..................................................................................................... 33 3.2.1 Heat Exchanger 1- Efficiency .............................................................................................. 34 3.2.2 Heat Exchanger 1- Effectiveness ........................................................................................ 34 3.2.3 Heat Exchanger 2- Efficiency .............................................................................................. 34 3.2.4 Heat Exchanger 2- Effectiveness ........................................................................................ 35

3.3 District Loop ................................................................................................................................. 36 3.4 Household Heat Meter Readings ................................................................................................ 38 3.5 CWEC Comparison ..................................................................................................................... 39 3.6 University of Calgary Irradiation .................................................................................................. 42

APPENDIX A Effectiveness Mathematic Description ............................................................................. 43 APPENDIX B System Schematic ........................................................................................................... 44 APPENDIX C List of Issues .................................................................................................................... 45 APPENDIX D System Control Modifications .......................................................................................... 50


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PROPRIETARY

LIST OF FIGURES Figure 1-1 System Energy Diagram ........................................................................................................................6 Figure 2-1 Weekly Incident Solar Energy for 2010-2011 ........................................................................................9 Figure 2-2 Weekly Totals of Solar Energy Collected ............................................................................................ 10 Figure 2-3 Weekly Totals of Solar Energy Injected Into STTS ............................................................................. 11 Figure 2-4 Weekly BTES Energy Flow ................................................................................................................. 13 Figure 2-5: Annual BTES Energy Flow .................................................................................................................. 14 Figure 2-6 BTES Temperature Sensor locations ................................................................................................. 15 Figure 2-7: BTES Core Temperature .................................................................................................................... 16 Figure 2-8: BTES Lateral Temperatures ............................................................................................................... 17 Figure 2-9 Weekly Solar Thermal Energy Delivered to HX-2 ............................................................................... 19 Figure 2-10 Weekly Energy Delivered to District Loop ......................................................................................... 20 Figure 2-11 District Energy Distribution ................................................................................................................ 21 Figure 2-12 Weekly District Energy Distribution by Source .................................................................................. 22 Figure 2-13 Weekly Totals of Gas Used (GM-1) .................................................................................................. 23 Figure 2-14 Weekly PV Energy ............................................................................................................................ 24 Figure 2-15: Collector Loop ................................................................................................................................... 25 Figure 2-16: STTS HX-1 ........................................................................................................................................ 26 Figure 2-17: BTES Charging Flow Rate (l/s) ......................................................................................................... 27 Figure 2-18: BTES Discharging Flow Rate (l/s) .................................................................................................... 27 Figure 2-19: STTS HX-2 ........................................................................................................................................ 28 Figure 2-20: District Loop ...................................................................................................................................... 29 Figure 2-21: Glycol pH ........................................................................................................................................... 30 Figure 2-22: Glycol Concentration ......................................................................................................................... 30 Figure 2-23 Ambient Temperatures ...................................................................................................................... 31 Figure 3-1: Collector Efficiency .............................................................................................................................. 32 Figure 3-2 Block 1 vs. All Blocks .......................................................................................................................... 33 Figure 3-3: HX-1 effectiveness .............................................................................................................................. 34 Figure 3-4: HX-2 effectiveness .............................................................................................................................. 35 Figure 3-5: District loop Temperature Drop ........................................................................................................... 36 Figure 3-6: District Loop Supply Temperature....................................................................................................... 37 Figure 3-7: Heat Meter Readings .......................................................................................................................... 38


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PROPRIETARY

LIST OF TABLES Table 1-1 Summary .................................................................................................................................................7 Table 2-1 Incident Solar Energy for 2010-2011 ................................................................................................... 10 Table 2-2 Energy Collected for 2010-2011........................................................................................................... 11 Table 2-3 Solar Energy Injected to STTS for 2010-2011 ..................................................................................... 12 Table 2-4 BTES Energy for 2010-2011 ................................................................................................................ 13 Table 2-5 BTES Core Temperatures for 2010-2011 ............................................................................................ 16 Table 2-6 BTES Lateral Array 1 Temperatures for 2010-2011 ............................................................................ 17 Table 2-7 BTES Lateral Array 2 Temperatures for 2010-2011 ............................................................................ 17 Table 2-8 Solar Thermal Energy Delivered for 2010-2011 ................................................................................... 19 Table 2-9 Thermal Energy Delivered to DHL for 2010-2011 ................................................................................ 20 Table 2-10 Gas Usage for 2010-2011 .................................................................................................................. 23 Table 2-11 PV Energy for 2010-2011 ................................................................................................................... 25 Table 3-1: TMY Annual Heating Degree Comparison ........................................................................................... 39 Table 3-2: CWEC Annual Solar Irradiation Comparison: SR-2 ............................................................................. 40 Table 3-3: CWEC Annual Solar Irradiation Comparison: SR-1 ............................................................................. 41 Table 3-4: TMY Annual Solar Irradiation Comparison ........................................................................................... 42 Table D-1 – System Control Modifications ............................................................................................................ 50


CM002171 5 Science Applications International Corporation

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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 2010 to June 2011. The data summarized in Section 2 is analysed and discussed in Section 3.

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.

http://www.dlsc.ca/



(SAIC Canada)

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1.4 Overview Figure 1-1 depicts 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

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4058.9 GJ

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1.5 Summary Table 1-1 provides a summary for 2010-2011.

Table 1-1 Summary 2010-2011 2009-2010 2008-2009 2007-2008

Total Incident Solar Energy 12480.0 GJ 12709.1 GJ 13902.0 GJ 13321 GJ

Total Solar Energy Collected 4058.9 GJ 4274.5 GJ 4390.9 GJ 4469 GJ

Total Solar Energy Delivered to STTS 3929.7 GJ 4042.6 GJ 4330.3 GJ 4855 GJ

Total Energy Delivered to BTES 2262.7 GJ 2499.4 GJ 2713.3 GJ 2609 GJ

Total Energy Extracted from BTES 1218.7 GJ 863.7 GJ 561.7 GJ 152 GJ

Total Energy Delivered from STTS to HX-2 2754.4. GJ 2555.5 GJ 1980.6 GJ 2345 GJ

Total Solar Energy Delivered to District Loop 2455.9. GJ 2026.1 GJ 1791.9 GJ 1671GJ

Natural Gas Energy Used 436.2 GJ 543.6 GJ 1194.3 GJ 1574 GJ

Boiler Thermal Energy Delivered to the District Loop 403.3 GJ 519.5 GJ 1172.2 GJ 1365 GJ

Total Energy Delivered to District Loop 2859.3 GJ 2545.1 GJ 2964.2 GJ 3035.7 GJ

Average Solar Collector Efficiency 32.5% 32.5% 31.6% 34%

Average Efficiency of HX-1 96.8% 94.6% 98.6% 92%

Average Efficiency of HX-2 89.2% 79.3% 90.4% 71%

Average BTES core temperature 51.9 °C 44.3 °C 41.4 °C 40 °C

PV energy generated 11.54 GJ 12.81 GJ 13.66 GJ 10 GJ

Solar Fraction 85.9% 79.6% 60.4% 55%

Heating Degree Days (18°C ref.) 4911 5069 5393 5274



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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 2010.

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 2010-2011, starting on July 1, 2010. Pyranometer readings show small negative values at night. This is typical 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 2010-2011

Based on SR-1, the global horizontal insolation (GHI) received at the project location was 4,584 MJ/m² over the year. This is 7.8% lower than the typical value of 4974 MJ/m² expected for this area, as found in the CWEC (Canadian Weather for Energy Calculations) file for Calgary Airport (See section 3.6 for more information). It is also noted that the 12,480 GJ of solar radiation incident on the collectors in 2010/11 is the lowest of the four years since the system became operational, and is 6.2% lower than the average of those previous three years.

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Table 2-1 lists a set of values that describe the ranges of incident solar radiation. 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 2010-2011

Description SR-1

Horizontal [GJ]

SR-2 Slope [GJ]

Maximum Energy Week 403.9 396.1 Minimum Energy Week 45.4 73.3 Average Weekly Value 201.9 238.8 Annual Total 10564.1 12480.0

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 and Table 2-2 shows an annual summary of the collected energy. Due to heavy snow fall during the 21st week (November 18 – 25), an overall negative value of collected energy was calculated (-2.4 GJ), which is displayed as zero on this chart.

Figure 2-2 Weekly Totals of Solar Energy Collected

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Table 2-2 Energy Collected for 2010-2011

Description Energy [GJ] Highest Weekly Value 155.8 Lowest Weekly Value -2.4 Average Weekly Value 77.6 Annual Total 4058.9

The 4,059 GJ of solar energy collected is the lowest value of the four years the project has operated, 7.3% less than the average of the first three years. This is due primarily to the low insolation value in this year (6.2% lower than the average of the first three years), but also due to the expected decline in collector efficiency, as the BTES field slowly charges up with more heat over the first few years of operation.

2.2.2 Solar Energy Collection Efficiency Collection efficiency for the year is the ratio of solar energy collected to solar energy available. 4058.9 GJ Collected 12480.0 GJ Available

Collection Efficiency = Collected = 32.5% Available This is the same average collector efficiency as in the previous year.

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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Table 2-3 Solar Energy Injected to STTS for 2010-2011

Description Energy [GJ] Highest Weekly Value 151.7 Lowest Weekly Value 0.0 Average Weekly Value 75.1 Annual Total 3929.7

The 3,930 GJ delivered to the STTS is 3.2% lower than the value for solar energy collected. While some heat is lost to the atmosphere in HX-1 and the short lengths of pipe adjacent to it, this difference is likely largely due to instrumentation error. The 3.2% difference is within expectations of accuracy.

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2.3 Long Term Energy Storage (BTES) Figure 2-4 shows the energy sent to the BTES and the energy recovered from the BTES; Table 2-4 shows an annual summary of the energy injected into and extracted out of the BTES.

Figure 2-4 Weekly BTES Energy Flow

Table 2-4 BTES Energy for 2010-2011

Description Sent to BTES [GJ]

From BTES [GJ]

Maximum Energy Week 124.5 130.4 Minimum Energy Week 0.0 0.0 Average Weekly Value 43.2 23.4 Annual Total 2262.7 1218.7

Figure 2-5 shows the energy injected into the BTES and energy recovered from the BTES for the first four years of operation. The 54% recovery fraction from the BTES (extracted energy divided by delivered energy) is significantly higher than previous years (34%, 21% and 6% for the previous years, from most recent to oldest). This is as anticipated, as the BTES is now approaching full charge and thus moving toward stable year-to-year operation. A control change, where both BTES pumps run simultaneously improved the ability of the system to recover energy stored in the BTES was also a contributing factor. Note that the energy delivered to the BTES is 9.5% lower this year than previous. The largest contributing factor to this is the lower solar radiation available this year (6.2% less).

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(SAIC Canada)

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Figure 2-5: Annual BTES Energy Flow

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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 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. Since some of the temperature sensors have failed, the readings are taken from the remaining reliable temperature sensors: TS22-1, TS22-5 and TS22-7. A weighted average of the three sensors is taken where TS22-5 (the sensor located in the middle) is weighted as double.

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

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LLaatteerraall AArrrraayy 11 LLaatteerraall AArrrraayy 22

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(SAIC Canada)

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Figure 2-7: BTES Core Temperature

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

Table 2-5 BTES Core Temperatures for 2010-2011

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

(°C) TS-22-1 39.8 62.9 37.3 48.5 TS-22-5 43.5 67.8 44.9 56.2 TS-22-7 41.1 62.1 42.0 50.9

Average 2010-2011 64.3 41.4 51.9 Average 2009-2010 65.1 42.3 53.0 Average 2008-2009 59.5 34.0 46.1

Note: Some erroneous data was ignored in Table 2-5: 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 2009-2011. The annual average is taken as a weighted average where TS22-5 (closest sensor to the centre) is weighted as double. Note that the BTES core temperature achieved its highest values yet in the summer of 2010, exceeding 65°C, and that the BTES was coolest to a lower temperature in March of 2010 than for the previous two years. This latter is due to a change in the control which allowed for more heat to be drawn from the BTES during the heating season. This control change, which allows the BTES to operate effectively at a lower average temperature, will lessen overall thermal losses from the BTES, and thereby increase the average solar fraction of the system in future years.



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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 2010-2011

Description Min. (°C) Max. (°C) Average (°C) TS-23-1 (Centre) 36.3 68.9 50.5 TS-23-2 34.8 65.5 49.6 TS-23-3 33.0 63.6 47.7 TS-23-4 31.7 61.9 45.6 TS-23-5 30.4 59.6 42.8 TS-23-6 29.3 56.7 40.2 TS-23-7(Outside Edge) 28.4 54.8 39.1

Table 2-7 BTES Lateral Array 2 Temperatures for 2010-2011

Description Min. (°C) Max. (°C) Average (°C) TS-24-1 (Centre) 35.9 70.7 50.7 TS-24-2 34.8 67.8 50.3 TS-24-3 0.8 62.4 29.0 TS-24-4 31.8 63.1 45.8 TS-24-5 30.6 60.8 43.5 TS-24-6 29.5 58.6 41.1 TS-24-7(Outside Edge) 28.9 56.0 39.5

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 the BTES lateral temperature profile for both months at a instantaneous point when the flow was off for at least 4 hours- the specific instantaneous points were chosen since they are the maximum and minimum temperatures reached in the BTES. Note that TS24-3 has not operated properly since May 2010. The plot also shows the lateral BTES temperatures for the previous year. The lower temperatures in the current year, as compared to the previous year, result from the change in control strategy that has improved heat recovery from the BTES, thus allowing the BTES to operate effectively at lower temperatures.

Figure 2-8: BTES Lateral Temperatures



(SAIC Canada)

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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. For the balance of the year, the district loop operates continuously.

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

Table 2-8 Solar Thermal Energy Delivered for 2010-2011

Description Energy (GJ) Highest Weekly Value 142.9 Lowest Weekly Value 1.7 Average Weekly Value 53.0 Annual Total 2754.4.

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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-24 and FM-3.

Figure 2-10 Weekly Energy Delivered to District Loop

Table 2-9 Thermal Energy Delivered to DHL for 2010-2011

Description Solar Energy (GJ)

Boiler Energy (GJ) Total (GJ)

Highest Weekly Value 135.1 84.8 178.0 Lowest Weekly Value 2.9 0.0 2.9 Average Weekly Value 47.2 7.8 55.0 Annual Total 2455.9. 403.3 2859.3

The solar energy delivered to the district loop, shown in Figure 2-10, is delivered from the STTS tanks which may have been directly collected from the solar collectors or recovered from the BTES. The 2,859 GJ delivered to the district loop is significantly more than the previous year – by 12.3% - but is very close to the average of the previous three years combined. The most dominant factor in determining the amount of heat delivered to the district loop is the average temperature throughout the year (or heating degree-days). This value is also influenced by the behaviour of the residents (e.g. thermostat settings, open windows). Figure 2-11 shows the cumulative annual distribution of the energy sent to the district loop by the boiler, direct solar energy and indirect (BTES) energy. The following figure shows the same data, but in a weekly format that

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clearly shows that the gas boilers are only used during peak heating times, and also shows that the size of the load being met by heat recovered from the BTES (indirect solar) decreases steadily from November through February, as expected.

Figure 2-11 District Energy Distribution

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Figure 2-12 Weekly District Energy Distribution by Source

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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 2-13 Weekly Totals of Gas Used (GM-1)

Table 2-10 Gas Usage for 2010-2011

Description Usage (m3) Equivalent Energy (GJ)

Highest Weekly Value 1960.0 71.5 Lowest Weekly Value 0.0 0.0 Average Weekly Value 229.8 8.4 Annual Total 11950.0 436.2

Gas usage declined by almost 20% over the previous year, even though 12.3% more total heat was delivered to the homes this year. The boiler efficiency is the ratio 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.

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Energy delivered to the district loop: 403.3GJ. Equivalent gas energy input: 436.2GJ.

Boiler Efficiency = Boiler Energy Delivered

= 92.4% Gas Energy Input

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: 2455.9. GJ. Total Energy Delivered: 2859.3 GJ.

Solar Fraction = Solar Energy Delivered = 85.9% Total Energy Delivered

2.9 Solar PV Energy Delivered Figure 2-14 gives the daily PV energy delivered as 240 VAC power. Note that almost no energy was collected during the 21st week due to a heavy snow fall.

Figure 2-14 Weekly PV Energy

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Table 2-11 PV Energy for 2010-2011

Description Energy (GJ) Highest Weekly Value 0.44 Lowest Weekly Value 0.03 Average Weekly Value 0.24 Annual Total 11.54

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 2-15 shows that the flow rate in the collector loop was above 14 l/s for approximately 700 hours in the 2010-2011 year, and above this same value for approximately 1,100 hours in the previous two years. Figure 2-15 shows the flow curve for the collector loop (P1) and Figure 2-16 shows the flow curve for the water flow between the STTS and HX1 (P2). The plots show the curves for the past three years.

Figure 2-15: Collector Loop

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(SAIC Canada)

PROPRIETARY

Figure 2-16: STTS HX-1

Figure 2-15 and Figure 2-16 show that the collector loop and STTS - HX-1 loop have similar flow distributions and that they operated at maximum flow for approximately 700 hours in the year; this is less than the previous years where the glycol flow was at maximum flow for approximately 1000 hours. The “stepped” nature of the curves in Figure 2-15 shows that the control algorithms for this collector loop pump are biased toward certain specific pump rate set points (approximately 25%, 50% and 100% of full rate, based on the flatter sections of the curve). The 50% value, at approximately 8 l/s corresponds to start-up conditions where the glycol pumps operate at 50% while bypassing the heat exchanger (HX-1), until the “stagnant” glycol is warmed sufficiently to deliver heat across HX-1. Figure 2 -15 shows only the tendency to operate at maximum and minimum values, on the water side of HX-1.“

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(SAIC Canada)

PROPRIETARY

Figure 2-17 shows the flow through the BTES while charging and Figure 2-18 shows the flow while discharging (P6).

Figure 2-17: BTES Charging Flow Rate (l/s)

Figure 2-18: BTES Discharging Flow Rate (l/s)

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(SAIC Canada)

PROPRIETARY

The BTES pumps (P 6.1, P6.2) are constant flow pumps that serve for both charging and discharging, and are expected to provide a flow rate in the range of 3 l/s. It is evident from Figure 2-17 and Figure 2-18 that the BTES flow rate has degraded slightly, with most of the degradation occurring after 2008-2009, since which it has remained fairly stable: . The average flow rate in 2008-2009 was 2.75 while the average flow in 2010-2011 was 2.58. The exception to this is the approximately 800 hours of discharging in 2010-2011, when both pumps were operated in parallel, something which did not occur in earlier years, or during BTES charging. The BTES discharging flow in Figure 2-18 shows that the flow generally operated longer throughout the year when charging as compared to discharging. Figure 2-19 shows the flow from the STTS to HX-2 (P4); this flow transfers heat from the STTS to the district loop.

Figure 2-19: STTS HX-2

The low flow rate in 2009-2010 (shown in Figure 2-19) was caused by pump issues and deposits in HX-2. Pump maintenance and heat exchanger cleaning has allowed higher flow rates in 2010-2011. The pump operated for approximately 7,100 hours this year, 6,400 hours in 2009-2010 and 5,800 hours in 2008-2009. The pump is running more often since there is more heat available in the BTES; more heat is transferred from the STTS to the district loop. Figure 2-20 shows the district loop flow rate; the flow has remained relatively constant from year to year. The district loop was operating for 8060 hours; 92 % of the year.

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(SAIC Canada)

PROPRIETARY

Figure 2-20: District Loop

2.11 Fluid Properties The following plots show a summary of the results from fluid property tests of the collector loop glycol. Figure 2-21 shows the glycol pH and the reserve alkalinity. Note that during early operation, through April of 2009, the fluid properties were checked frequently. After initial system problems were resolved and the system operation and fluid properties were demonstrated to be more stable, the time between inspections has been increased. Currently the fluid is only tested when an incident causes a need for testing – it is recommended that regular fluid testing resumes.

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(SAIC Canada)

PROPRIETARY

Figure 2-21: Glycol pH

Figure 2-22shows the glycol concentration of the glycol – water solution.

Figure 2-22: Glycol Concentration

2.12 Electrical Energy from Local Utility The Energy Centre electric meter connected to the data collection system (EM-1) has operated only sporadically throughout the year. The data collected is insufficient to allow appropriate analysis.

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Gly

col C

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tion



(SAIC Canada)

PROPRIETARY

2.13 Ambient Temperatures Minimum, maximum, and average weekly temperatures for the year are given in Figure 2-23. 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 2-23 Ambient Temperatures

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ent T

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re (°

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Max Min Average EnvCan Calgary 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), along with a linear fit to this data. The plot also shows the efficiency curve for the model of collector used at Drake Landing. 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 occasionally (e.g. exceptionally high or low efficiencies). 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 14 L/s and includes irradiation measurements between 700 and 1000 W/m². The NSTF 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 (solar time) when the incident angle is close to normal, and thus to laboratory test conditions. Some transient data was also eleminated by only including 30 minutes or more of consecutive measurements which meet the criteria described above. The first and last measurements in each time sequence that met the conditions were also ignored, as they may well have contained some time with transient operations.

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 varies in the DLSC system. The back of

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Collector Efficiency Measured Efficiency (η)

NSTF Efficiency Curve

Measured data - Linear Trend



(SAIC Canada)

PROPRIETARY

the solar collectors at DLSC are also protected (by the garage roofs) while they are un-insulated and exposed during the NSTF 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 3-2 is approximately 22% which is close to the expected 23%. The plot shows some random scatter at low flow rates but the overall trend is stable.

Figure 3-2 Block 1 vs. All Blocks

For unknown reasons, at high flow rates, it appears that the flow through block 1 reaches a maximum at 3.25 L/s. The flow meter (FM6) has a maximum flow rate of 4 L/s so the measurements are likely accurate.

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 significantly 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, but is also very difficult to measure dynamically. 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

y = 0.2208x

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(SAIC Canada)

PROPRIETARY

cause scatter in heat exchanger effectiveness. Because of this, the effectiveness is calculated and plotted at design flow rates.

3.2.1 Heat Exchanger 1- Efficiency The efficiency of heat exchanger 1 is calculated as follows: Energy delivered to STTS: 3929.7 GJ. Solar Energy Collected: 4058.9 GJ.

HX-1 Efficiency = Energy Delivered to STTS = 96.8% 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 are both above 12.5 l/s. The minimum flow rate is used to reduce scatter in the plot caused by transient effects.

Figure 3-3: HX-1 effectiveness

An 80% effectiveness is to be expected in a heat exchanger. It is assumed that scatter in the plot is caused by transient data points.

3.2.3 Heat Exchanger 2- Efficiency The efficiency of heat exchanger 2 is calculated as follows: Solar Energy Delivered to District Loop: 2455.9. GJ. Energy Extracted: 2754.4. GJ.

HX-2 Efficiency = Solar Energy Delivered to Domestic Loop = 89.2% Energy Extracted An efficiency of 89.2 is lower than expected which gives reason to doubt the accuracy of the instrumentation.

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(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 and cold side of the heat exchanger is above 5 l/s. The minimum flow rate is used to reduce scatter in the plot caused by transient effects.

Figure 3-4: HX-2 effectiveness

An 80% effectiveness is to be expected in a heat exchanger. It is assumed that scatter in the plot is caused by transient data points, however there is very little scatter in Figure 3-4.

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(SAIC Canada)

PROPRIETARY

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

Figure 3-5: District loop Temperature Drop

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(SAIC Canada)

PROPRIETARY

Figure 3-6: District Loop Supply Temperature

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.

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(SAIC Canada)

PROPRIETARY

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 166.7 GJ, a loss of 5.8%, at the last meter reading on June 14, 2011. This is consistent with the previous year when the loss was 5.1%.

Figure 3-7: Heat Meter Readings

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Metasys Energy Meters 2862.37 GJ

2695.63 GJ



(SAIC Canada)

PROPRIETARY

3.5 CWEC 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-(daily maximum – daily minimum)/2)1.

Table 3-1: TMY Annual Heating Degree Comparison

Heating Degree Day

CWEC TS-1

2007-2008 2008-2009 2009-2010 2010-2011 July 86 38 97 90 52 August 99 142 113 128 59 September 252 265 244 169 196 October 377 389 392 517 273 November 648 608 518 493 635 December 801 834 942 965 749 January 812 781 770 742 799 February 684 710 738 631 793 March 675 554 698 464 653 April 412 529 446 395 421 May 277 258 271 322 201 June 132 167 163 153 79

Total 5257 5274 5393 5069 4911 % Difference TMY 0.0% 0.3% 2.5% -3.6% -5.5%

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

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 surface at a tilt 45° facing south. The solar irradiation measured at DLSC from the tilted pyranometer (SR-2) is compared to the Canadian Weather for Energy Calculations (CWEC) solar irradiation values (as adjusted to a 45° south-facing tilt using the sky modelling algorithms incorporated in the TRNSYS software package).

Table 3-2: CWEC Annual Solar Irradiation Comparison: SR-2

Available Solar Energy (MJ/m²)

CWEC at 45° SR-2 (45°)

Month 2007-2008 2008-2009 2009-2010 2010-2011

July 709 749 675 662 646 August 661 573 626 591 585 September 568 560 564 631 410 October 560 474 499 288 445 November 364 320 259 320 288 December 300 225 174 238 240 January 402 274 323 225 247 February 441 399 420 363 372 March 600 525 606 494 484 April 588 577 599 579 594 May 628 552 654 541 581

June 617 590 666 555 533

Total 6,437 5,816 6,065 5,490 5,449

% Difference CWEC 0.0% -9.6% -5.8% -14.7% -15.3%



(SAIC Canada)

PROPRIETARY

Table 3-3: CWEC Annual Solar Irradiation Comparison: SR-1


CWEC SR-1 (Horizontal)

Month 2007-2008 2008-2009 2009-2010 2010-2011


June 679 644 741 659 595

Total 4,974 4,629 4,963 4,649 4,584

% Difference CWEC 0.0% -6.9% -0.2% -6.5% -7.8%



(SAIC Canada)

PROPRIETARY

3.6 University of Calgary Irradiation Table 3-4 is a monthly summary of the available solar energy on a horizontal surface (GHI). 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 and measurements taken at the University of Calgary.

Table 3-4: TMY Annual Solar Irradiation Comparison


CWEC (GHI) UofC SR-1 UofC SR-1

Month 2009-2010 2010-2011


June 679 567 659 553 595

Total 4,974 4,436 4,649 4,225 4,584

% Difference CWEC -10.8% -6.5% -15.0% -7.8%

% Difference UofC 4.8% 8.5%



(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

TTcmTTcm

orTTcm

TTcmQQ

−−

−−

==

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 2010.07 01-Mar-10 01-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 Controll issues were causing the boiler to run unneccessarily so it was mannually turned off.

2010.11 29-Apr-10 03-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 unlost flow rates.

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

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



(SAIC Canada)

PROPRIETARY

ID No. Start Date End Date Description Comments 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.

2010.16 14-Aug-10 23-Sep-10 Electric Meter EPM-1 has not reported electric consumption since August 14, 2010. The meter started working again after a grid power outage on September 23.

2010.17 13-Aug-10 13-Aug-10 Pressure Sensor Calibration

JCI performed a calibration of PS3 on this date.

2010.18 19-Aug-10 23-Sep-10 Loss of Glycol It was noticed on this date that there was a loss of glycol from the PRV on Block 1. It was later determined that the loss of glycol was caused by an expansion tank bladder failure. Glycol was added on September 23 and the bladder was replaced on September 27.

2010.19 19-Aug-10 19-Aug-10 HX-2 Cleaning HX2 was dismantled and cleaned. The cleaning had little affect on the performance data since there is negligable heat demand in the district loop.

2010.20 14-Sep-10 14-Sep-10 Ts-8, TS-9, TS-10 erroneous reading

Due to temperature sensor calibrations/ checking, TS-8, TS-9. TS-10 reported erroneous data for a single reading. These sensors are not used in energy calculations.

2010.21 21-Sep-10 21-Sep-10 TS-3.2, TS-12 erroneous reading

Due to temperature sensor calibrations, TS-12 reported erronious data at 12:50 and TS3.2 reported erroneous data at 15:00. Neither of these sensors are used in energy calculations.

2010.22 23-Sep-10 23-Sep-10 Grid Power Outage

The grid power was out from 10:20 to 11:10 on this date. Backup pumps were powered by the emergency power system causing the battery voltage to drop slightly. The system operated as expected during the power outage and returned to normal operation when the power came back on.



(SAIC Canada)

PROPRIETARY

ID No. Start Date End Date Description Comments 2010.23 27-Sep-10 4-Oct-10 Back-up pumps

running The solar collection backup pumps (P1.2, P2.2) were automaticall turned on due to programing/ control issues, which were resolved on October 4, 2010.

2010.24 14-Oct-10 16-Nov-10 Electric Meter EPM-1 has not reported electric consumption since October 14, 2010.

2010.25 13-Sep-10 17-Oct-10 Glycol Pressure High glycol pressures were caused by caused was caused by a low air pressure in HX-2. Once the cause was discovered, the air pressure in both expansion tanks were set to 20psi.

2010.26 16-Nov-10 16-Nov-10 Power Outage There was a power outage at 12:45 am which lasted for approximately 2 hours. The back-up power system performed as expected.

2010.27 16-Nov-10 25-Nov-10 Snow Heavy snow fall covered both the solar thermal and PV panels resulting in little to no production for a ten day period.

2010.28 18-Nov-10 -- TS 2.1 and 2.2 failure

It was noted on this date that the two temperature sensors have failed. Because of their failure neither sensor is used in the controls.

2010.29 1-Nov-10 5-Apr-11 Solar Collector Flow Tests

The solar collection glycol loop controls were overridden several times throughout the month to study the effects of lower flow rates.

2010.30 11-Dec-10 12-Mar-11 BTES Pumps In order to increase heat transfer from the BTES during cold weather, the BTES pumps were manually turned on to operate simultaneously. Running both pumps together increased the flow rate through the BTES from 2.5 - 2.7 L/s to 3 L/s.

2011.01 12-Jan-11 12-Jan-11 Boiler Control Adjustment

On this date the boiler controls were modified to better accommodate low load conditions.

2011.02 14-Jan-11 14-Jan-11 Lost Data A UPS was shut down for maintenance/ replacement on this date which resulted in a loss of a data point at 9:40.



(SAIC Canada)

PROPRIETARY

ID No. Start Date End Date Description Comments 2011.03 17-Jan-11 17-Jan-11 P-6.2 Repair The removal of P6.2 resulted in some

air entering the BTES loop causing low flow (1.6 - 2.4 L/s) for a period of approximately 12 hours. Fluid filters in the BTES loop were also replaced during this period.

2011.04 30-Jan-11 1-Feb-11 PV Output The recorded data of the photovoltaic output is following an unusual pattern: it did not produce energy on a sunny day (Jan. 31).

2011.05 5-Apr-11 5-Apr-11 Glycol Flow Control Change

The solar collector (glycol) loop controls were modified where flow was decreased to increase the temperature rise over the collectors. The objective is to obtain a temperature rise of 20°, rather than 15°.

2011.06 11-Dec-10 12-Mar-11 BTES Pumps The BTES controlls were overridden during the winter months to avoid unneccesary charging.

2011.07 20-Apr-11 -- PV Expansion The rooftop PV system was expanded, and started operation on April 20, 2011. Instrumentation has not yet been installed to measure the output of the expanded array, so this data is not included in this report, although the net electricity usage as measured by EM-1 will decline accordingly.

2011.08 1-Jun-11 2-Jun-11 Electric Meter EPM-1 stopped reporting electricity consumption at 7pm on June 1st. The issue was resolved at 10:30 on June 2nd by briefly cutting the meters power supply. The meter display reported error B4 and error D7.

2011.09 14-Jun-11 14-Jun-11 Electric Meter EPM-1 stopped reporting electricity consumption at 2:50pm on June 14, the issue was resolved at 11:20 am the same day.

2011.10 24-Jun-11 29-Jun-11 Electric Meter EPM-1 stopped reporting electricity consumption at 9:50 pm on June 14, the issue was resolved at 10:20 am on June 29.



(SAIC Canada)

PROPRIETARY

ID No. Start Date End Date Description Comments 2011.11 2-Jun-11 Electric Meter EPM-1 stopped reporting electricity

consumption at 9:50 pm on June 14, the issue was resolved at 10:20 am on June 29.

2011.12 30-Jun-11 -- Electric Meter EPM-1 stopped reporting electricity consumption on June 31. Communication from the electric meter was momentarily regained on July 3 for approximately 20 minutes. The electric meter has been offline since.



(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 = 58°C

19-Jan-10 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 above TS14 to start, and it stops if the difference drops to less than 3.

annual report for 2010-2011 - drake landing solar communitybased on sr-1, the global horizontal...

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