Cooling Towers for District Cooling  Georges Hoeterickx  Evapco Europe
Cooling Towers for District Cooling  Design considerations  <ul><li>Approach  :  </li></ul><ul><li>Difference between cool...
Design considerations  Cooling tower size versus approach Approach ° F
Design considerations  Minimum approach   <ul><li>CTI Certification under STD-201   </li></ul><ul><li>Certification is lim...
Cooling Towers for   District Cooling  Cooling tower range   <ul><li>Range  : </li></ul><ul><li>Difference between cooling...
Design considerations Cooling   tower size versus range  Range C.T. Size
Cooling Towers for District Cooling  Design considerations  <ul><li>Avoid recirculation  :  </li></ul><ul><li>Bypass of wa...
Design considerations  Avoid recirculation   <ul><li>Top of cooling tower should be at least level  </li></ul><ul><li>with...
Design considerations  Avoid recirculation   <ul><li>Fan discharge velocity : min. 1200 fpm  (6 m/sec). </li></ul><ul><li>...
Design considerations – two side air inlet  Avoid recirculation   <ul><li>Limit downward velocity  - two side air inlet un...
Design considerations – single air inlet  Avoid recirculation   <ul><li>Limit downward velocity  - single air inlet units ...
Cooling Towers for District Cooling  Fan motors  <ul><li>High efficiency </li></ul><ul><li>50° C Rise </li></ul><ul><li>Sp...
Cooling Towers for District Cooling  Fan Motors <ul><li>Use of VFD’s for fan motors  :  </li></ul><ul><li>Allow to control...
Design considerations  VFD’s for fan motors  <ul><li>Energy saving ?  </li></ul><ul><li>Condenser water temp  1°F </li></u...
Design considerations  VFD’s for fan motors <ul><li>Water consumption :  </li></ul><ul><li>Air flow  Water consumption  </...
Design considerations  VFD’s for fan motors <ul><li>Min. RPM for gear  </li></ul><ul><li>(motor speed  ≥  450 RPM) </li></...
Cooling Towers for District Cooling  <ul><li>Cooling Tower Basin  :  </li></ul><ul><li>Hold circulating water of the tower...
Design considerations Cooling Tower Basin    <ul><li>Common basin </li></ul><ul><li>+ Easier basin and cooling tower const...
Design considerations Cooling Tower Basin  <ul><li>Individual Basin per Cell  </li></ul><ul><li>+  Easier for maintance (w...
Design considerations Water Outlets
Design considerations Cooling Tower Bassin  <ul><li>Sound mats to reduce water noise   </li></ul><ul><li>Noise reduction f...
Cost distribution main items
Cooling Tower Structure <ul><li>Typical requirements :  </li></ul>
Cooling Towers for District Cooling FRP Structure <ul><li>Reputable manufacturers have their components third party tested...
FRP Structure Boron Free Advantex glass assures a longer life of the structure
FRP Structure Obtain the specified quality
FRP Structure UV protection   <ul><li>UV degradation and moisture penetration will have influence life time of an FRP cool...
FRP structure     UV protection <ul><li>Surface veil material of non woven polyester fabric to prevent fiber blow out </li...
FRP structure UV protection STRUCTURAL  RESIN  55-25% GLASS 45-75% WOVEN ROVEN AND CONTINUOUS GLASS 250 MILS OR MORE CORRO...
FRP structure  UV protection <ul><li>Useful life of UV projected components </li></ul>
FRP structure  UV protection <ul><li>How to verify UV protection quality  ?  </li></ul><ul><li>Have samples of different w...
FRP Structure Fire retardancy <ul><li>Fire resistance and damage control of the  </li></ul><ul><li>FRP structure.  </li></ul>
FRP structure  Fire retardancy   <ul><li>Design with high quality, heat resistant / fire retardant resin systems, Class 1 ...
Obtain the required quality FRP structure  <ul><li>Major part of the cooling tower cost  </li></ul><ul><li>Most critical i...
Obtain the required quality FRP structure <ul><li>1. Demand cooling tower supplier names the FRP source and ask delivery c...
Obtain the required quality FRP structure <ul><li>1. Demand cooling tower supplier names the FRP source and ask delivery c...
Obtain the required quality FRP structure <ul><li>1. Demand cooling tower supplier names the FRP source and ask delivery c...
Cooling tower fans
Obtain the best quality  Fans   <ul><li>Fans are selected for a given airflow and static pressure  </li></ul><ul><li>Fan d...
Cooling tower fans  Noise definition  <ul><li>Specify sound pressure  </li></ul><ul><li>in dB(A) measured 1,5 meter  </li>...
Cooling tower fans Noise
Cooling tower fans Comparison  -  2000 ton tower - 196 m³/ sec @  160 Pa pressure drop  Fan dia  Nbr Blades Rpm  Tip speed...
Cooling tower fans Fan power vs cost  – 2000 ton tower – 196 m³/sec @ 160 Pa  pressure drop Fan dia  Tower price  Fan Powe...
Cooling tower fans Comparison -  5000 ton tower - 375 m³/ sec @  160 Pa pressure drop   Fan dia  Nbr  Blades Rpm  Tip spee...
Cooling tower fans Fan power – noise vs cost -  5000 ton tower –  375 m³/ sec @ 160 Pa pressure drop   Fan dia  Tower pric...
Obtain the required quality  Fan stacks
Fan stacks  Material  <ul><li>Height : 7– 10 ft - … </li></ul><ul><li>Material : Class 1 – flame spread rating 25 </li></u...
Fan stacks <ul><li>Make sure fan deck floor opening matches fan cylinder </li></ul><ul><li>Smooth air inlet </li></ul><ul>...
Obtain the required quality Air inlet louvers  Water stays in …  Sunlight stays out!
Air inlet louvers  Single pass FRP Blade louvers   <ul><li>Waterdroplets tend to splash out when fans are shut off.  </li>...
Air inlet louvers   Two pass PVC air inlet louvers <ul><li>Minimise splash-out  </li></ul><ul><li>Direct sunlight is block...
Two Pass Air inlet louvers   <ul><li>Typical two pass air inlet louvers  </li></ul>
Obtain the required quality  Drift eliminators
Obtain the required quality  Drift eliminators   <ul><li>Drift rates : 0,01 to 0,0005 % of tower flow rate </li></ul><ul><...
Drift eliminators  Quality  <ul><li>Drift rate dependends on:  </li></ul><ul><li>Waterloading  </li></ul><ul><li>Air veloc...
Drift eliminators  Efficiency comparison
Drift eliminators  Efficiency confirmation <ul><li>Ask your cooling tower supplier names manufacturer of DE </li></ul><ul>...
<ul><li>Air passes through area with minimum resistance </li></ul><ul><li>Air bypass reduces cooling effect </li></ul><ul>...
Drift losses Design considerations : air seals
Cooling Towers Fill Obtain the right quality <ul><li>Performance </li></ul>
Cooling Tower Fill Film Fill Design Considerations
Cooling Tower Fill Vertically Offset Flute PVC Film Fill
Cooling Tower Fill Vertically Fluted PVC Film Fill
Cooling Tower Fill
<ul><li>PVC </li></ul><ul><li>Fill spacing: min 19 mm </li></ul><ul><li>Fill thickness: 10 – 20 nils before formation </li...
Cooling Towers for District Cooling
Cooling Towers for District Cooling <ul><li>Obtain the specified and correct  </li></ul><ul><li>quality level ! </li></ul>
<ul><li>Thank you </li></ul><ul><li>Georges Hoeterickx </li></ul>
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George hoetricks, evapco

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  • Step one to avoid recirculation is to make sure that the top of the cooling tower should be at least level with the enclosure. Today , we as engineers are still fighting daily with architects on this issue ! or the right measurements to avoid recirculation are it is completely overlooked
  • Often VFD’s are promted to save energy in applications using electrical motors. Are we saving energy when applying VFDs on cooling towers ? We know that by lowering the condensing temperature with 1°F , the chiller efficiency improves with 3% . At the same time are the fan kw of the cooling towers more or less 5 % of the motor kw of the chiller. In other words , we will not save energy when considering all elements when reducing the cooling tower fan speed by using VFD’s.
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  • Fans are selected for a given air flow and static pressure caused in the cooling tower. Fan design parameters or characteristiques include the diameter, speed , the number and the shape of the blades and blade width. The paramters have all their influence on cost , power consumption and noise.
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  • George hoetricks, evapco

    1. 1. Cooling Towers for District Cooling Georges Hoeterickx Evapco Europe
    2. 2. Cooling Towers for District Cooling Design considerations <ul><li>Approach : </li></ul><ul><li>Difference between cooling tower water outlet temp. and design entering wb temp. </li></ul>
    3. 3. Design considerations Cooling tower size versus approach Approach ° F
    4. 4. Design considerations Minimum approach <ul><li>CTI Certification under STD-201 </li></ul><ul><li>Certification is limited to thermal operating conditions….. and a cooling approach of 2.8°C (5°F) or greater…. </li></ul>
    5. 5. Cooling Towers for District Cooling Cooling tower range <ul><li>Range : </li></ul><ul><li>Difference between cooling tower water </li></ul><ul><li>inlet and cooling tower outlet temperature. </li></ul>
    6. 6. Design considerations Cooling tower size versus range Range C.T. Size
    7. 7. Cooling Towers for District Cooling Design considerations <ul><li>Avoid recirculation : </li></ul><ul><li>Bypass of warm discharge air into the cooling tower air inlet will cause capacity losses. </li></ul>
    8. 8. Design considerations Avoid recirculation <ul><li>Top of cooling tower should be at least level </li></ul><ul><li>with enclosure. </li></ul>
    9. 9. Design considerations Avoid recirculation <ul><li>Fan discharge velocity : min. 1200 fpm (6 m/sec). </li></ul><ul><li>Downward velocity : max. 600 fpm </li></ul><ul><li>(3 m/sec). </li></ul>
    10. 10. Design considerations – two side air inlet Avoid recirculation <ul><li>Limit downward velocity - two side air inlet units </li></ul>
    11. 11. Design considerations – single air inlet Avoid recirculation <ul><li>Limit downward velocity - single air inlet units </li></ul>
    12. 12. Cooling Towers for District Cooling Fan motors <ul><li>High efficiency </li></ul><ul><li>50° C Rise </li></ul><ul><li>Space heaters </li></ul><ul><li>(avoid condensation) </li></ul><ul><li>VFD compatible </li></ul><ul><li>(insulated end shields) </li></ul>
    13. 13. Cooling Towers for District Cooling Fan Motors <ul><li>Use of VFD’s for fan motors : </li></ul><ul><li>Allow to control air flow through the cooling tower </li></ul><ul><li>Safe Fan KW </li></ul>
    14. 14. Design considerations VFD’s for fan motors <ul><li>Energy saving ? </li></ul><ul><li>Condenser water temp 1°F </li></ul><ul><li>Chiller efficiency 3% </li></ul><ul><li>Cooling tower kW = ~ 5 % </li></ul><ul><li>Chiller kW. </li></ul>
    15. 15. Design considerations VFD’s for fan motors <ul><li>Water consumption : </li></ul><ul><li>Air flow Water consumption </li></ul><ul><li>Plume formation : </li></ul><ul><li>Air flow Plume formation tendency </li></ul><ul><li>Noise control @ night </li></ul><ul><li>Fan @ half speed : – 9 dBA fan noise </li></ul><ul><li>(60% capacity) </li></ul>
    16. 16. Design considerations VFD’s for fan motors <ul><li>Min. RPM for gear </li></ul><ul><li>(motor speed ≥ 450 RPM) </li></ul><ul><li>Gear with mechanical oil pump for proper lubrication </li></ul>
    17. 17. Cooling Towers for District Cooling <ul><li>Cooling Tower Basin : </li></ul><ul><li>Hold circulating water of the tower. </li></ul>
    18. 18. Design considerations Cooling Tower Basin <ul><li>Common basin </li></ul><ul><li>+ Easier basin and cooling tower construction. </li></ul><ul><li>+ No need for equalizing connection </li></ul><ul><li>- Maintenance – sump cleaning </li></ul>
    19. 19. Design considerations Cooling Tower Basin <ul><li>Individual Basin per Cell </li></ul><ul><li>+ Easier for maintance (water) </li></ul><ul><li>- Need equalizing between basins. </li></ul><ul><li>- More costly construction </li></ul>
    20. 20. Design considerations Water Outlets
    21. 21. Design considerations Cooling Tower Bassin <ul><li>Sound mats to reduce water noise </li></ul><ul><li>Noise reduction function </li></ul><ul><li>number of layers </li></ul><ul><li>distance mats – water in basin ! </li></ul><ul><li>Sound mats will obstruct basin access : maintenance ! </li></ul>
    22. 22. Cost distribution main items
    23. 23. Cooling Tower Structure <ul><li>Typical requirements : </li></ul>
    24. 24. Cooling Towers for District Cooling FRP Structure <ul><li>Reputable manufacturers have their components third party tested per </li></ul><ul><li>ASTM E 84 for strength values and flamability </li></ul><ul><li>Ask if these evidences are part of contract submittals ! </li></ul>
    25. 25. FRP Structure Boron Free Advantex glass assures a longer life of the structure
    26. 26. FRP Structure Obtain the specified quality
    27. 27. FRP Structure UV protection <ul><li>UV degradation and moisture penetration will have influence life time of an FRP cooling tower </li></ul><ul><li>The UV rays will cause the decomposition of the polymers holding the fibre glass together </li></ul>
    28. 28. FRP structure UV protection <ul><li>Surface veil material of non woven polyester fabric to prevent fiber blow out </li></ul><ul><li>Surface veil creates a resin rich surface area to provide enhanced UV protection </li></ul><ul><li>One mil thickness of surface veil = </li></ul><ul><li>2 – 3 years life time </li></ul>
    29. 29. FRP structure UV protection STRUCTURAL RESIN 55-25% GLASS 45-75% WOVEN ROVEN AND CONTINUOUS GLASS 250 MILS OR MORE CORROSION BARRIER RESIN 60-70 % GLASS 30-40% MAT OR CLOTH 40-60 MILS EXTERNAL LINER RESIN RICH 80-90% GLASS 10-20% 15-20 MILS SURFACING VEIL TYPE C 10-20 MIL THICKNESS
    30. 30. FRP structure UV protection <ul><li>Useful life of UV projected components </li></ul>
    31. 31. FRP structure UV protection <ul><li>How to verify UV protection quality ? </li></ul><ul><li>Have samples of different weight veil material for comparison. </li></ul><ul><li>Variation in the visibility of the Continious </li></ul><ul><li>Filament Mat. </li></ul>
    32. 32. FRP Structure Fire retardancy <ul><li>Fire resistance and damage control of the </li></ul><ul><li>FRP structure. </li></ul>
    33. 33. FRP structure Fire retardancy <ul><li>Design with high quality, heat resistant / fire retardant resin systems, Class 1 type </li></ul><ul><li>Specify self extinguishing </li></ul><ul><li>High glass content = minimum burn rate </li></ul>
    34. 34. Obtain the required quality FRP structure <ul><li>Major part of the cooling tower cost </li></ul><ul><li>Most critical item for the cooling tower life time ! </li></ul><ul><li>How to obtain the required quality ? </li></ul>
    35. 35. Obtain the required quality FRP structure <ul><li>1. Demand cooling tower supplier names the FRP source and ask delivery certificates from the FRP manufacturer. </li></ul><ul><li>2. Reserve the right to inspect before delivery to verify Quality Process Map is complied with. </li></ul>
    36. 36. Obtain the required quality FRP structure <ul><li>1. Demand cooling tower supplier names the FRP source and ask delivery certificates from the FRP manufacturer. </li></ul><ul><li>2. Reserve the right to inspect before delivery to verify Quality Process Map is complied with. </li></ul>
    37. 37. Obtain the required quality FRP structure <ul><li>1. Demand cooling tower supplier names the FRP source and ask delivery certificates from the FRP manufacturer. </li></ul><ul><li>2. Reserve the right to inspect before delivery to verify Quality Process Map is complied with. </li></ul>
    38. 38. Cooling tower fans
    39. 39. Obtain the best quality Fans <ul><li>Fans are selected for a given airflow and static pressure </li></ul><ul><li>Fan design parameters : </li></ul><ul><li>diameter – speed – nbr and shape of blades – blade width </li></ul><ul><li>Fan design parameters influence : </li></ul><ul><li>cost – power consumption – noise </li></ul>
    40. 40. Cooling tower fans Noise definition <ul><li>Specify sound pressure </li></ul><ul><li>in dB(A) measured 1,5 meter </li></ul><ul><li>above fan discharge </li></ul><ul><li>(per CTI std ATC – 128) </li></ul>
    41. 41. Cooling tower fans Noise
    42. 42. Cooling tower fans Comparison - 2000 ton tower - 196 m³/ sec @ 160 Pa pressure drop Fan dia Nbr Blades Rpm Tip speed Sound Power Fan shaft Power Fan ft     m/sec dB(A) kW US $ 14 6 270.8 60.5 100.3 59.3 2100 16 7 193.9 49.5 95.6 53.2 3600 18 5 186.8 54.2 99 46 13500 18 * 4 137 40 86.3 54.9 45000
    43. 43. Cooling tower fans Fan power vs cost – 2000 ton tower – 196 m³/sec @ 160 Pa pressure drop Fan dia Tower price Fan Power ft % kW 14   - -  16 + 1, 25 % - 11 % 18 +8 % - 22 %
    44. 44. Cooling tower fans Comparison - 5000 ton tower - 375 m³/ sec @ 160 Pa pressure drop Fan dia Nbr Blades Rpm Tip speed Sound Power Fan shaft Power Fan ft     m/sec dB(A) kW US $ 22 6 226 44.2 106.3 106.3 9500 26 9 104.8 43.5 97.9 87.1 26000 26 6 89.7 37.2 90.6 104.2 60000 28 6 82.6 36.9 90 102.3 65000
    45. 45. Cooling tower fans Fan power – noise vs cost - 5000 ton tower – 375 m³/ sec @ 160 Pa pressure drop Fan dia Tower price Power Sound Power ft % kW dB (A) 22     106.3 26 + 7 % - 18 % 97.9 26 20% -2% 90.6 28 + 22% -4% 90
    46. 46. Obtain the required quality Fan stacks
    47. 47. Fan stacks Material <ul><li>Height : 7– 10 ft - … </li></ul><ul><li>Material : Class 1 – flame spread rating 25 </li></ul><ul><li>(Class II and Class III = Cheaper !) </li></ul><ul><li>UV resistance (gelcoat 20 mil). </li></ul><ul><li>Access door or removable panel </li></ul><ul><li>Assembly hardware SST </li></ul>
    48. 48. Fan stacks <ul><li>Make sure fan deck floor opening matches fan cylinder </li></ul><ul><li>Smooth air inlet </li></ul><ul><li>Fan tip clearance : 0,5% fan dia </li></ul>
    49. 49. Obtain the required quality Air inlet louvers Water stays in … Sunlight stays out!
    50. 50. Air inlet louvers Single pass FRP Blade louvers <ul><li>Waterdroplets tend to splash out when fans are shut off. </li></ul><ul><li>Sunlight still enters the cooling tower basin ! </li></ul>
    51. 51. Air inlet louvers Two pass PVC air inlet louvers <ul><li>Minimise splash-out </li></ul><ul><li>Direct sunlight is blocked from the water inside the tower and reducing the potential for algae formation ! </li></ul><ul><li>Minimum pressure drop </li></ul>
    52. 52. Two Pass Air inlet louvers <ul><li>Typical two pass air inlet louvers </li></ul>
    53. 53. Obtain the required quality Drift eliminators
    54. 54. Obtain the required quality Drift eliminators <ul><li>Drift rates : 0,01 to 0,0005 % of tower flow rate </li></ul><ul><li>Drift rate function of type DE, air velocity, water loading and spray nozzle types, … </li></ul>
    55. 55. Drift eliminators Quality <ul><li>Drift rate dependends on: </li></ul><ul><li>Waterloading </li></ul><ul><li>Air velocity </li></ul><ul><li>Spray nozzle arrangement </li></ul>
    56. 56. Drift eliminators Efficiency comparison
    57. 57. Drift eliminators Efficiency confirmation <ul><li>Ask your cooling tower supplier names manufacturer of DE </li></ul><ul><li>Demand independent test certifications according to accepted standards </li></ul>
    58. 58. <ul><li>Air passes through area with minimum resistance </li></ul><ul><li>Air bypass reduces cooling effect </li></ul><ul><li>Water loss because of higher air velocity </li></ul>Drift eliminators Execution on site
    59. 59. Drift losses Design considerations : air seals
    60. 60. Cooling Towers Fill Obtain the right quality <ul><li>Performance </li></ul>
    61. 61. Cooling Tower Fill Film Fill Design Considerations
    62. 62. Cooling Tower Fill Vertically Offset Flute PVC Film Fill
    63. 63. Cooling Tower Fill Vertically Fluted PVC Film Fill
    64. 64. Cooling Tower Fill
    65. 65. <ul><li>PVC </li></ul><ul><li>Fill spacing: min 19 mm </li></ul><ul><li>Fill thickness: 10 – 20 nils before formation </li></ul><ul><li>Flamability (ASTM E84 – max 5) </li></ul><ul><li>Designed to accomodate operational and specified Live load </li></ul>Cooling Tower Fill
    66. 66. Cooling Towers for District Cooling
    67. 67. Cooling Towers for District Cooling <ul><li>Obtain the specified and correct </li></ul><ul><li>quality level ! </li></ul>
    68. 68. <ul><li>Thank you </li></ul><ul><li>Georges Hoeterickx </li></ul>

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