evaluation report€¦ · this report presents an effectiveness of hvs automatic tube cleaning...

EVALUATION REPORT

HVS Automatic Tube Cleaning System

For

Suntec City Project

Chiller No: 1

31 August 2007

Content1) Executive Summary

2) Evaluation Report

Introduction

Project Background

Approach & Methodology

The Working Principle of HVS Automatic On-line Cleaning System

3) Result Analysis & Findings

Chiller Efficiency Analysis & Findings (kW/T)

Chiller Cooling Capacity Analysis & Findings (Ton)

Chiller Approach Temperature Analysis and Findings (°C)

4) Summary & Conclusion

5) Recommendations

6) Appendixes

Appendix A - Photos Presentation

Appendix B - Chiller Efficiency (kW/Ton)

Daily Data & Monthly Average (2007, 2006 & 2005)

Graphical Presentation (2007, 2006 & 2005)

Appendix C - Cooling Capacity (Ton)

Daily Data & Monthly Average (2007 & 2006)

Graphical Presentation (2007 & 2006)

Appendix D - Condenser Approach Temperature (°C)

Carrier Log Sheet (2007, 2006 & 2005)

Appendix E - Electricity Comparison Pattern

Daily Data & Monthly Average (2007, 2006 & 2005)

Executive Summary: This report presents an effectiveness of HVS Automatic Tube Cleaning System on Chiller Efficiency (kW/Ton), Cooling Production Capacity (Ton) and Approach Temperature (°C). The system was installed at Chiller No.1 of chilled water plant located at Suntec City in September 2006 as part of Energy Conservation Measures.

The effectiveness was evaluated using pre and post operating data of the HVS system recorded at 1-minute intervals for the period from Jan 2006 to July 2007 assuming all other operating equipment and schedule remains the same. Some major events during the evaluation period are listed in the followings:

Date Major Events

8 Jan 2006 Annual Shut Down Manual Brush Cleaning by Carrier 22Jul 2006 2nd Annual Shut Down Manual Brush Cleaning in 2006 by Carrier 27 Jul 2006 Fibrescope Analysis Conducted by MatCor Technology Aug 2006 Chiller 1 shut down for whole month for servicing

29 Sep 2006 Installation of HVS System Completed and operational 9 Oct 2006 HVS System is operational and commissioned

28 Mar 2007

2nd Fibrescope Analysis Conducted by MatCor Technology.

Inspection of condition of tubes by Owner’s Representatives.

Visual verification of tubes and Finger Scrubbing Test Conducted.

Mar 2007Till Jul 2007

Continuous Collating and Monitoring of the post-HVS performance data for the next few months.

The results show there was significant improvement on the chiller performance. Average chiller efficiency (kW/T) was improved about 10.9%, average condenser water approach temperature was improved about 36.36% and cooling production capacity was improved about 3.96%. This accounts for average energy savings of about 9% and average S$ savings of about S$80,500.00 per year.

Master Summary: Performance Evaluation of Chiller 1 before & after HVS Tube Cleaning System

Suntec BAS's Data Log Suntec BAS's Data Log Carrier's Log Suntec's LogChiller Efficiency (kW/T) Cooling Capacity (T) Approach Temperature ( oC) Electricity Utilised (kWH)

Date Yr 2007 Yr 2006 Year 2007 Year 2006 Yr 2007 Yr 2006 Yr 2005 Yr 2007 Yr 2006 Yr 2005

Jan 0.701 0.692 2239 2124 3.47 6.40 5.20 496500 690400 616600

Feb 0.696 0.699 2113 2211 3.59 6.30 5.80 423000 643600 553000

Mar 0.688 0.703 2148 2146 3.50 312800 761700 697100

Apr 0.679 0.710 2252 2144 4.12 6.90 501700 648600 502500

May 0.667 0.716 2256 2131 4.14 5.60 502500 742400 569200

Jun 0.662 0.733 2289 2167 6.20 5.60 674000 680800 401400

Jul 0.661 0.742 2361 2138 4.80 728800 417400 512900

Aug 2245 4.30 149300 595700

Sep 0.720 2060 4.60 3.80 202300 656400

Oct 0.715 2212 4.10 543700 725500

Nov 0.711 2327 217100 736800

Dec 0.705 2228 390800 698700

0.679 0.713 2238 2172 3.76 5.52 5.25 3639300 6088100 7265800

Table 1

Introduction:

One set of HVS Automatic Tube Cleaning Systems was installed at Chiller No. 1 (Carrier Chiller 2500 RT Model No: 17FA563) with an objective to enhance energy savings as part of our proposed energy conservation measures.

The effectiveness of the System was evaluated using the data of the period from Jan 2006 to July 2006 (pre-installation) and Jan 2007 to July 2007 (post installation) based on Chiller Efficiency (kW/T), Cooling Production Capacity (Ton) and Approach Temperature (°C) using past and present data recorded at 1-minute intervals.

The background information, evaluation methodology and findings are described in the following sections.

Project Background:

Fouling in the water tubes of chillers is the most common problems. The relatively thin and thermal conductive surface of heat exchange tube bundles are critical components to be kept free from fouling as these tube surfaces are the nerve-center of the heat removal system. If such surfaces are kept consistently cleanse of fouling, then heat transfer capability can be maintained at optimal level at all times.

The industrial norm of the measurement of chiller efficiency is by tracking the performance of chiller (based on kW/T) continuously during the operation hours – defined as the ratio of total energy used (kW) to the total production cooling capacity (Ton).

Higher kW/T values means that the chiller is using more energy to produce the same amount of chilled water. It indicates that the chiller is getting less efficient as a result of dirt accumulation inside the heat exchange tubes, thus, requiring more energy to cool a unit of chilled water.

Condenser water tubes of the chiller no.1 was cleaned annually by using manual brush. Its condenser water approach temperature was found to be ranging from 3.8 to 6.9 °C, average efficiency was ranging from 0.692kW/T to 0.742kW/T and average cooling capacity was ranging from 2,124 Ton to 2,211 Ton.

To operate the chiller performance within the optimal operating range, it is important to maintain the condenser approach temperature within the optimal or ‘healthy’ band range (normally specified by chiller manufacturers). The industrial rule-of-thumb is that for every 1°C increase in approach temperature, there is a corresponding increase in the chiller energy consumption by 3%~5%. Conversely, if there is a reduction of 1oC in approach temperature, there is also a corresponding decrease in the chiller energy consumption by 3%~5%.

Approach & Methodology:

Our approach and methodology for evaluation of the chiller effectiveness due to the HVS system is

To collate and analyze historical Chiller Efficiency (kW/T), Chiller Cooling Production Capacity (Ton) and Approach Temperature (°C) data of Suntec City Chiller No: 1 before the installation of HVS System (Note: Performance data as obtained from Carrier Service Log Sheets, Suntec’s Maintenance Records and Suntec’s EMS Data Logging System before the installation of HVS Cleaning System shall be considered as Pre-HVS System chiller’s performance data)

To collate and analyze historical Chiller Efficiency (kW/T), Chiller Cooling Production Capacity (Ton) and Approach Temperature (°C) data of Suntec City Chiller No: 1 after the installation of HVS Cleaning System (Note: Performance data as obtained from Carrier Service Log Sheets, Suntec’s Maintenance Records and Suntec’s BAS Data Logging System after the installation of HVS Cleaning System shall be considered as Post-HVS System chiller’s performance data)

To compare pre-HVS performance data and post-HVS performance data of Chiller No: 1 to ascertain if there are any existing operating trends in Chiller Efficiency (kW/T), Chiller Cooling Production Capacity (Ton) and Approach Temperature (°C) assuming that any other operating equipment and schedules remain the same during the evaluation period.

To evaluate the impact of HVS System on the performance of Chiller No: 1 based on Chiller Efficiency (kW/T), Chiller Cooling Capacity (Ton) and Approach Temperature (°C) using past and current data.

To verify the cleaning effectiveness of HVS Brush Ball in cleaning grooved internal heat exchange tubes based on the photographic evidence as obtained from Fibrescope Analysis conducted by MatCor Technology.

To verify the extent of fouling, if any, due to scaling, slime and/or particulate deposit at the end of a 6-month post-HVS operational period (from 29 Sep 2006 till 28 Mar 2007) for the heat exchange tubes in Chiller No: 1 based on visual observation, photographic evidence and Finger Scrubbing Test.

To calculate energy savings in percentage (P) before and after HVS system installation as follows:

P = (A - B)/A x 100

Where

A is average pre-measured data

B is average post-measured data

The Working Principle of HVS System:

The HVS Automatic On-line Cleaning System was designed to allow the ‘piggy-backing’ of the inherent moving force of the circulating fluid of the heat exchange system.

HVS Brush Balls and/or HVS Elastomeric Balls of the appropriate diameter and weight are dispensed into the condenser tubes. These are then pushed along by hydraulic pressure already present from the flow of fluid running through the heat exchange core. The HVS Cleaning Devices are drawn into the network of small tubes and brush out dirt deposits accumulated on the interior of the tube. After exiting the tube, the cleaning devices are then diverted from the main pipeline into a hydrodynamic chamber which cleans off the scrubbed dirt deposits and readies them for another pass in the system.

The concept behind this approach is based on the random actions of certain geometrical configurations and physical properties of HVS Elastomeric Balls or/and HVS Brush Balls scrubbing against the inside diameter of the heat exchange tubes, as it passes through these tubes. The foulants or deposits in these tubes would then be pushed/’brushed’ out by these balls. Due to the dirt removal being a physical process, it is not subject to the variability of fluid chemistry, hence this method of cleaning is robust.

Once in place, the HVS System is fully automated, allowing for continuous, as opposed to periodic cleaning performance. This makes a big reduction in energy consumption, as the heat exchange tubes are kept consistently clean by the constant brushing and removal of foulings – thus ensuring an optimum heat transfer interface.

Basic Schematic Illustration of the Working Principleof HVS Automatic On-line Cleaning System

Chiller Efficiency Analysis & Findings:

It is observed that immediately after the Annual Shutdown Manual Cleaning done on 8 Jan 2006, the average Efficiency of Chiller 1 has improved from 0.717 kW/T to 0.692 kW/T.

Thereafter the Efficiency of Chiller No.1 slowly and steadily deteriorates to 0.742 kW/T from Jan 2006 until the 2nd Manual Cleaning which was conducted on 22 Jul 2006. The deterioration in kW/T between the period of 1st Manual cleaning in Jan 2006 and the 2nd

manual cleaning in Jul 2006 is due to the gradual build-up of dirt deposit over this period.

From Graph 1, it can be estimated that the deterioration of chiller efficiency over 7 months (from Jan 2006 to July 2006) is as follows:

Chiller Efficiency Deterioration = (EffiJul06 –EffiJan06)/EffiJan06 x 100% = (0.742-0.692)/0.692 x 100%

= 7.2% (without HVS System)

Dirt deposits was observed over the internal surface of tubes of Chiller No. 1 before each manual clean as evidenced in Photo Ref: 6, 7, 8, 9,10 & 11. (Please refer to Appendix A – Photos Presentation)

Immediately after the 2nd manual cleaning, Fibrescope Inspection was conducted by Matcor Technology on 27 Jul 2006. Despite two labour-intensive manual nylon brush cleaning procedures performed by Carrier in Jan 2006 and July 2006, scale deposition still remain in the grooves of enhanced tubes of Chiller No. 1 as evidenced in Photo Ref: 8 & 9. (Please refer to Appendix A – Photos Presentation)

From the service record, Chiller No.1 was not operational from 20 July 2007 till end Aug 2006 due to major servicing procedures. The month of Sep 2006 was allocated for the installation of HVS Cleaning System of which the installation was completed on 29 Sep 2006 and commissioned on 9 Oct 2006.

It is interesting to note that since Sep 2006 (since the installation of HVS Tube Cleaning System), the Chiller Efficiency of Chiller No.1 has improved gradually from 0.720 kW/T in Sep 2006 to 0.661 kW/T in Jul 2007.

From Graph 1, taking the Jul 2006 value of 0.742 kW/T (Just before ASD on 22 July 2006) and the July 2007 of 0.661 kW/T (Post-HVS System – after 10 months of operation), it can be estimated that Chiller No. 1 performance has improved by 10.9% since the implementation of HVS System in Sep 2006.

The Energy Efficiency Improvement Formula is derived as follows:

The Energy Efficiency Improvement (Post-HVS System) = (EffiJul06 –EffiJul07)/EffiJul06 x 100%

= (0.742-0.661)/0.742 x 100% = 10.9%

Suntec City Chiller No.1Average Monthly Chiller Efficiency For Year 2006 & 2007

0.692

0.699 0.7

030.7

100.7

16 0.720

0.715

0.711

0.705

0.701

0.696

0.688

0.667

0.662

0.661

0.679

0.733

0.742

0.650

0.660

0.670

0.680

0.690

0.700

0.710

0.720

0.730

0.740

0.750

Chi

ller E

ffici

ency

(kW

/T)

Average kW/T 0.692 0.699 0.703 0.710 0.716 0.733 0.742 0.720 0.715 0.711 0.705 0.701 0.696 0.688 0.679 0.667 0.662 0.661

Jan-06 Feb-06 Mar-06 Apr-06 May-06 Jun-06 Jul-06 Aug-06 Sep-06 Oct-06 Nov-06 Dec-06 Jan-07 Feb-07 Mar-07 Apr-07 May-07 Jun-07 Jul-07

(Source: kW/T as obtained from Suntec Automatic Data Logging System)

08 Jan 2006Just After 1st Annual Shut

Down Manual Cleaning

27 July 20061st Fiberscope Analysis Done

29 September 2006Installation of HVS System Completed

Chiller Under Service

Legend : (Jul 06 to Jul 07)Before Installation of HVS Cleaning System

After Installation of HVS Cleaning SystemNote:

Energy Efficiency of Chiller 1 has improved by 10.9% (Post-HVS System)

9 October 2006HVS System is commissioned

UnderService

22 July 2006Just Before 2nd Shut

Down Manual Cleaning

28 March 20072nd Fiberscope Analysis Done

Graph 1

Suntec City Chiller No. 1Chiller Efficiency Trend for Year 2006 & 2007

0.7100.716

0.733

0.742

0.7200.715

0.667

0.662

0.661

0.692

0.6990.703

0.7050.711

0.679

0.701

0.696

0.688

0.620

0.640

0.660

0.680

0.700

0.720

0.740

0.760

Chi

ller E

ffici

ency

(kW

/T)

Yr 2006 0.692 0.699 0.703 0.710 0.716 0.733 0.742 0.720 0.715 0.711 0.705

Yr 2007 0.701 0.696 0.688 0.679 0.667 0.662 0.661

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

9 October 2007HVS System

Commissioned

28 July 2006Just after 2nd Annual

Manual Brush Cleaning

8 January 2006Just After 1st Annual Shut Down Manual

Brush Cleaning Legend :

Before Installation of HVS Cleaning System After Installation of HVS Cleaning System

28 March 2007Fibrescope

Analysis Done

Under Service

(Source: kW/T as obtained from Suntec Automatic Data Logging System)

Chiller Under Service

Graph 2

22 July 20061st Fiberscope Analysis Done

Chiller Cooling Capacity Analysis & Findings:

Based on the Cooling Capacity data obtained from EMS System and analyzed on a daily basis from Jan 2006 until Jul 2006 (Pre-HVS) & Jan 2007 until Jul 2007 (Post-HVS System), it can be observed that the monthly average cooling capacity has improved by 3.96% over the same period. (Please refer to Graph 3)

The improvement to the average cooling capacity is derived as follows:

The Cooling Capacity Improvement (Post-HVS System)

=(Cooling Capacity Avg(Jan 07 – Jul07) – Cooling Capacity Avg(Jan 06 – Jul 06))/(Cooling Capacity Avg(Jan

06 – Jul 06)) x 100%

= (2,237-2,152)/2,152 x 100% = 3.96%

From Graph 4, it is observed that the efficiency (kW/T) of the chiller has deteriorated over the period from Jan 2006 to Jul 2006 (pre-HVS System) due to dirt accumulation within the tubes. The higher energy consumption is expected to off-set the reduction in heat transfer due to dirt accumulation within the tubes.

However, from Sep 2006 till Dec 2006 (Post-HVS System) and also Jan 2007 to Jul 2007 (Post-HVS System) as shown in Graph 5, there is a gradual decrease in the value of the chiller efficiency (kW/T) with a corresponding gradual increase in cooling capacity. This observation shows that the condenser tubes have become cleaner after implementation of the HVS Cleaning System, which is more effective method than the annual manual brush cleaning.

With the HVS system, the grooves of enhanced tubes are being consistently cleansed. This can be seen from the chiller efficiency that has recorded a much lower value (0.661 kW/T) than the kW/T value immediately before manual cleaning (0.742 kW/T) and immediately after manual cleaning (0.692 kW/T).

However, once the chiller system and its numerous heat exchange tubes reach their thermal equilibrium, the chiller performance will stabilize at an optimum level.

Suntec City Chiller No.1 Average Monthly Cooling Capacity For Year 2006 & 2007

(Source: Ton Value as obtained from Suntec Automatic Data Logging System)

21242144

2131

2167

2138

2060

22392252 2256

2289

22282212

2146

2327

2211

2245

2148

2361

2113

2000

2100

2200

2300

2400

2500

Coo

ling

Cap

acity

(Ton

Val

ue)

Before 2124 2211 2146 2144 2131 2167 2138 2060 2212 2327 2228

After 2239 2113 2148 2252 2256 2289 2361 2245


Legend : (Jan - Jul)Before Installation of HVS Cleaning System (Average = 2152) - 2006

After Installation of HVS Cleaning System (Average = 2237) - 2007Note:

Cooling Capacity of Chiller No. 1 has improved by 3.96% (Post-HVS Cleaning System)

Under Service

Graph 3

Suntec Chiller No. 1Trend Comparison of Chiller Efficiency & Cooling Capacity for Year 2006

(Source: kW/T & Ton Value as obtained from Suntec Automatic Data Logging System)

0.692

0.703

0.716

0.733

0.742

0.720

0.7150.711

0.705

0.710

0.699

2124

2211

2167

2060

2212

2327

2228

2138

2131

21442146

0.660

0.670

0.680

0.690

0.700

0.710

0.720

0.730

0.740

0.750

Chi

ller E

ffici

ency

(kW

/T)

2000

2050

2100

2150

2200

2250

2300

2350

2400

Coo

ling

Cap

acity

(Ton

Val

ue)

kW/T 0.692 0.699 0.703 0.710 0.716 0.733 0.742 0.720 0.715 0.711 0.705

Ton Value 2124 2211 2146 2144 2131 2167 2138 2060 2212 2327 2228

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov DecUnder

Service

Graph 4

Suntec City Chiller No. 1 Trend Comparison of Chiller Efficiency & Cooling Capacity for Year 2007

(Source: kW/T & Ton Value as obtained from Suntec Automatic Data Logging System)

0.701

0.696

0.688

0.679

0.667

0.6610.662

2239

2148

2289

2361

22562252

2113

0.660

0.670

0.680

0.690

0.700

0.710

0.720

0.730

0.740

0.750

Chi

ller E

ffici

ency

(kW

/T)

2000

2050

2100

2150

2200

2250

2300

2350

2400

Coo

ling

Cap

acity

(Ton

Val

ue)

kW/T 0.701 0.696 0.688 0.679 0.667 0.662 0.661

Ton Value 2239 2113 2148 2252 2256 2289 2361

Jan Feb Mar Apr May Jun Jul

Graph 5

Approach Temperature Analysis & Findings:

The condenser approach temperature of the chiller system has an impact on its performance. If the approach temperature of the chiller system increases beyond the specified upper limit (normally specified by chiller manufacturer), then it can be strongly said that the heat exchange tubes are very dirty and cleaning is required. A complete shut-down of the chiller system is then needed to initiate a manual cleaning of the dirty tubes to restore their heat transfer efficiency.

From Graph 6, based on actual data obtained from Carrier’s Log sheet and analysed for the period from Jan 2005 to July 2005, Jan 2006 to July 2006 (Pre-HVS System), and Jan 2007 to July 2007 (Post-HVS System), it was observed that the monthly average approach temperature is 5.91°C (Pre-HVS System) and 3.76°C (Post-HVS System).

Hence, the condenser approach temperature has improved by 36.36% from Year 2005 to Year 2007 as a result of the implementation of HVS Cleaning System.

The improvement to the average approach temperature is derived as follows:

The Approach Temperature Improvement (Post-HVS System)

= (Approach Temperature Avg(Jan05 – Jul05,Jan06-Jul06) – Approach Temperature Avg(Jan07-Jul07)) / (Approach Temperature Avg(Jan05 – Jul05,Jan 06 – Jul06) x 100%

= (5.91-3.76)/5.91 x 100%

= 36.36%

Suntec City Chiller No. 1Chiller Efficiency Trend for Year 2005, 2006 & 2007

(Source: Approach Temperature Data as obtained from Carrier Log Sheet)

5.2

5.85.6 5.6

4.8

4.3

3.8

6.46.3

6.2

4.6

4.1

3.473.59 3.5

4.12 4.14

6.9

3

3.5

4

4.5

5

5.5

6

6.5

7

7.5

App

roac

h Te

mp

°C

Yr 2005 5.2 5.8 6.9 5.6 5.6 4.8 4.3 3.8

Yr 2006 6.4 6.3 6.2 4.6 4.1

Yr 2007 3.47 3.59 3.5 4.12 4.14


WithHVS Cleaning System

Legend Without HVS Cleaning System (Year 2006) Without HVS Cleaning System (Year 2005) With HVS Cleaning System (Year 2007)

Note: Approach Temperature Improved by 36.3% between 2005 & 2007

Graph 6

WithoutHVS Cleaning System

WithoutHVS Cleaning System

Suntec City Chiller No. 1Trend Line Comparison between kW & Ton (From Jan to July)

1460

1480

1500

1520

1540

1560

1580

1600

2100 2150 2200 2250 2300 2350 2400

(T)

(KW

)

2007 (Post-HVS) 2006 (Pre-HVS) Linear (2007 (Post-HVS)) Linear (2006 (Pre-HVS))

Pre-HVSJan 2006 to Jul 2006

Post-HVSJan 2007 to Jul 2007

Savings due to improved kW/T

Savings due to improved cooling capacity

(Ton)pre (Ton)post

Suntec City Chiller No. 1 Trend Line Comparison between kW/T & Ton (From Jan to July)

0.650

0.660

0.670

0.680

0.690

0.700

0.710

0.720

2100 2150 2200 2250 2300 2350 2400

(T)

(kW

/T)

2007 (Post-HVS) 2006 (Pre-HVS) Expon. (2006 (Pre-HVS)) Expon. (2007 (Post-HVS))

Pre-HVSJan 2006 to Jul 2006

Post-HVSJan 2007 to Jul 2007

Summary & Conclusion:

From Graph 1 – after the installation of HVS Tube Cleaning System from Sep 2006 onwards, the Chiller Efficiency of Chiller No.1 has improved gradually from 0.720 kW/T in Sep 2006 to 0.661 kW/T in Jul 2007. Taking the July 2006 value of 0.742 kW/T (Just before ASD on 22 July 2006) and the July 2007 value of 0.661 kW/T (Post-HVS System – after 10 months of operation), it can be seen that Chiller No.1 efficiency has improved at 10.9% since the implementation of HVS System in Sep 2006.

Immediately after the Annual Shutdown Manual Cleaning done on 8 Jan 2006, the average Efficiency of Chiller No. 1 has been improved to 0.692 kW/RT. However, as seen from Graph 2, the energy efficiency of Chiller No.1 (Pre-HVS System) gradually deteriorates from 0.692 kW/T in Jan 2006 to 0.742 kW/T in July 2006 until the 2nd

Manual Cleaning conducted on 22 Jul 2006.

From Graph 3, 4 & 5 (Pre-HVS System between Jan 2006 & Jul 2006 & Post-HVS System between Jan 2007 & Jul 2007), the cooling capacity of Chiller No. 1 has increased and it corresponds with a decrease of the kW/T values as shown in Graph 4 & 5. It can be also be seen from Graph 4 that there is a sharp increase in the cooling capacity from Sep 2006 onwards (after HVS System is installed). This indicates that the grooves of the enhanced tubes are being consistently cleansed by HVS Brush Balls of the dirt deposits which cannot be reached using the ASD manual brush cleaning method. Based on the cooling capacities obtained (Pre-HVS System between Jan 2006 & Jul 2006 & Post-HVS System between Jan 2007 & Jul 2007), the chiller cooling capacity has improved by 3.96%.

Graph 6 shows that the improvement in condenser water approach temperature was about 36.36% based on the data (Period from Jan to July for years 2005 & 2007). The improvement in approach temperature was 2.15 °C which corresponds to an average energy savings of 5.02%. The Energy Saving due to a reduction in the condenser water approach temperature can be calculated as follows:

Energy Savings due to a reduction in Condenser Water Approach Temperature (Periods from Jan to Jul for 2005, 2006 & 2007)

Average condenser water temperature improvement = (5.91-3.76) = 2.15 °C Average chiller efficiency (pre-HVS System) = (0.692 + 0.742)/2 = 0.717 kW/T Average chiller efficiency (post-HVS System) = (0.701 + 0.661)/2 = 0.681 kW/T Average chiller efficiency Improvement = (0.717 – 0.681)/0.717 = 5.02%

Energy Savings for every 1 °C of approach temperature improvement= 5.02%/2.15 = 2.4%

A visual and physical check was conducted on 28 Mar 2007 using the Finger-Scrubbing Technique. It was observed that there was no staining of finger despite vigorous scrubbing on the internal surface of tubes. This is shown and evidenced in Photos Ref: 12, 13, 14, 15, 16, 17, 18 & 19.

Summary & Conclusion:

Based on the findings, there is a total energy savings of about 9% for the period from Jan 2007 and July 2007 compared to the corresponding period in year 2006. However, for the period from May 2007 to July 2007(Post-HVS System), it was observed that the kW/T value of Chiller No. 1 has consistently been hovering around the lower bandwidth of 0.661~0.667 kW/T after installation of the HVS system. This represents the optimum operating conditions and based on these conditions, there is a potential energy savings of about 11%.

Recommendation:

With the proven and validated cleaning technique of HVS Cleaning System using HVS Brush Ball specially designed for grooved tube application, we strongly recommend that such automatic cleaning system to be incorporated in all existing heat exchangers to maximize chiller efficiency and to fully exploit the inherent potential savings.

With HVS Automatic Tube Cleaning System, the conventional regular annual shutdown manual cleaning can be replaced since the System can clean the tubes and maintain optimal heat transfer efficiency of the chiller. This will in turn derive further ASD labour savings and water savings.

Therefore, with the incorporation of HVS Automatic Online Cleaning System for tube & shell heat exchangers, there will be tangible reduction in energy usage (as a result of constantly cleansed internal diameter of tube surface which in turns maintain an optimal heat transfer efficiency), intangible savings (as a result of virtually no system down-time for schedule manual cleaning – hence maintaining consistent throughput), substantial reduction in water consumption (as a result of reduced frequency of manual cleaning) and a reduction in chemical waste into the environment.

Report By:

Chesterton International Property Consultants Pte Ltd

Appendix A

Photos Presentation

Site Location

Complete Intergration of HVS Cleaning System

Annual Shut down manual brush cleaning

Condition of Grooved Tubes (Before cleaning)

Condition of Grooved Tubes (After Cleaning)

Background on Suntec’s Chiller 1 System:

2-pass centrifugal chiller of 2500 RT from Carrier Singapore Model No: 17FA563.

There is a total of 1561 heat exchange tubes for each chiller.

The internal diameter of the heat exchange tube is 16.05mm.

The length of the heat exchanger is 6000mm.

The Flow Rate is 23,000 litre per minute.

The condenser water out pipe diameter is 24 inch.

The overall system pressure is between 9 bars~10 bars.

Site location – Suntec City Chiller No: 1

Photo Ref: 1

Complete Integration of HVS Cleaning Systemon Suntec’s Chiller 1 System:

HVS Automatic Cleaning System installed at Chiller No: 1

Inspection of HVS System Central Control Module

Photo Ref: 2

Photo Ref: 3

Chiller No: 1 undergoing Annual Shut DownManual Brush Cleaning on 8 Jan 2006

Opening End Cover of Chiller No:1 on 8 Jan 2006For Annual Shut-Down Manual Cleaning

Lowering End Cover of Chiller No:1 on 8 Jan 2006For Annual Shut-Down 1st Manual Cleaning

Photo Ref: 4

Photo Ref: 5

Condition of tubes of Chiller No: 1 (Before Cleaning)as observed on 8 Jan 2006 during Annual Shutdown

Slimy condition of internal tube surface (before 1st Manual Cleaning done on 8 Jan 2006)

Layer of dirt deposit on internal tube surface (before 1st Manual Cleaning done on 8 Jan 2006)

Photo Ref: 6

Photo Ref: 7

Condition of Grooved Tubes of Chiller No: 1 using Fibrescopy Camera taken on 27 July 2006

Stubborn residue scale in groove of tube of Chiller No:1 (After 2nd Manual Cleaning done on 27 July 2006)

Stubborn residue scale in groove of tube of Chiller No:1 (After 2nd Manual Cleaning done on 27 July 2006)

Photo Ref: 8

Photo Ref: 9

Condition of tubes of Chiller No: 1 (Before the 2nd Manual Cleaning on 27 July 2006)

Dirt accumulation between the 1st and 2nd Manual Cleaning(Before 2nd Manual Cleaning on 27 July 2006)

Dirt accumulation between the 1st and 2nd Manual Cleaning(Before 2nd Manual Cleaning on 27 July 2006)

Photo Ref: 10

Photo Ref: 11

Tube Cleanliness Verification By Finger-Scrubbing TestConducted on 28 Mar 2007 (6 months after installation of

HVS Cleaning System from Sep 2006 ~ Mar 2007)

Random Finger-Scrubbing Test on tubes of Chiller No:1Conducted on 28 Mar 2007 (for Top-most Tubes)

Tubes surface observed to be completely free of dirt or slime as indicated by the clean fingers after the Scrubbing Test

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Random Finger-Scrubbing Test on tubes of Chiller No:1Conducted on 28 Mar 2007 (for Left-most Tubes)

Tubes Surface observed to be completely free of dirt or slime as indicated by the clean fingers after the Scrubbing Test

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Random Finger-Scrubbing Test on tubes of Chiller No:1Conducted on 28 Mar 2007 (for Right-most tubes)


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HVS Cleaning System from Sep 2006 ~ Mar 2007

Random Finger-Scrubbing Test on tubes of Chiller No:1Conducted on 28 Mar 2007 (for Bottom-most Tubes)


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Tube Cleanliness Verification By Fibrescope InspectionConducted on 28 Mar 2007 (6 months after installation of


Verification of condition of tubes of Chiller No:1 using Fibrescope Analysis on 28 Mar 2007


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Grooves of tubes is free from scale or dirt depositswith copper surface clearly seen indicating clean tubes

Whitish remnants over tube surface due to the removal ofscale residue under the action of HVS Brush Ball

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Grooves of tubes is free from scale or dirt depositswith copper surface clearly seen indicating clean tubes

Whitish remnants over tube surface due to the removal ofscale residue under the action of HVS Brush Ball

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evaluation report€¦ · this report presents an effectiveness of hvs automatic tube cleaning...

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