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Main Menu Mike Morin 407-388-8226 CT/HX.

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Presentation on theme: "Main Menu Mike Morin 407-388-8226 CT/HX."— Presentation transcript:

1 Main Menu Mike Morin CT/HX

2 Main Menu

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5 Key to a Cooling Tower – Evaporation

6 Main Menu Evaporation…

7 Main Menu Evaporation…

8 Main Menu Evaporation…

9 Main Menu Cooling Towers Types of Cooling Tower/Systems

10 Main Menu Fluid Coolers/Evaporative Condensers Types of Cooling Tower/Systems

11 Main Menu Rivers/Bays Types of Cooling Tower/Systems

12 Main Menu Spray Ponds Types of Cooling Tower/Systems

13 Main Menu Types of Cooling Towers: Induced Draft vs. Forced Draft

14 Main Menu Types of Cooling Towers: Induced Draft vs. Forced Draft

15 Main Menu Types of Cooling Towers: Natural Draft Air movement is dependent upon the difference in density between the entering air and internal air

16 Main Menu Types of Cooling Towers: Counterflow vs. Crossflow

17 Main Menu Types of Cooling Towers: Counterflow vs. Crossflow

18 Main Menu Types of Cooling Towers: Open Circuit vs. Closed Circuit

19 Main Menu Types of Cooling Towers: Open Circuit vs. Closed Circuit

20 Main Menu Types of Cooling Tower Fans Centrifugal Fans – Typically Forced Draft high volume/static pressure high energy consumption require approximately double HP of an equivalent tonnage Axial fan tower. quiet operation decibels quieter than standard axial fan

21 Main Menu Types of Cooling Tower Fans Axial Flow Fans – Typically Induced Draft high volume / low static pressure low energy consumption low sound fans available

22 Main Menu Cooling Towers by the Book Terms and Definitions BTU (British Thermal Unit) – A Btu is the heat energy required to raise the temperature of one pound of water one degree Fahrenheit in the range from 32 – 212 degrees F. An evaporative cooling ton is 15,000 Btu’s per hour as opposed to 12,000 Btu’s for refrigeration applications

23 Main Menu Cooling Towers by the Book Terms and Definitions Approach – The difference between the temperature of the cold water leaving the tower and the wet-bulb temperature of the air. Wet-Bulb – The lowest temperature that water theoretically can reach by evaporation. **Wet-bulb and Approach are the extreme parameters in selection and design of cooling towers **

24 Main Menu Cooling Towers by the Book Terms and Definitions Dry-bulb – entering ambient temperature Range – the difference between the hot water entering the tower and the cold water leaving the tower, also known as Delta T (∆T) Cell – smallest tower division that operate independently with regard to air/water flow

25 Main Menu Cooling Towers by the Book Terms and Definitions Make-up – the amount of water required to replace normal losses caused by bleed, drift and evaporation Drift – the water entrained in the exit air flow and discharged to the atmosphere – not including evaporation Bleed – water that is discharged to waste to help keep the dissolved solids concentration below a certain limit.

26 Main Menu Cooling Towers by the Book Design Symbols & Formulas Range (∆T) = T(1) – T(2) T(1) = Entering Water Temperature T(2) = Leaving Water Temperature ∆T = Delta T or Range

27 Main Menu Cooling Towers by the Book Design Symbols & Formulas Tonnage = GPM x ∆T x 500/15,000 One Cooling Tower Ton = 15,000 BTU/HR ∆T = Delta T or Range = T(1) – T(2)

28 Main Menu Cooling Towers by the Book Design Symbols & Formulas Approach = T(2) – T(wb) T(2) = Leaving Water Temperature Wet-Bulb – The lowest temperature that water theoretically can reach by evaporation.

29 Main Menu Cooling Towers by the Book Typical Commercial HVAC Design Conditions for Florida: Range:95°F to 85°F Wet-bulb: 79°F or 80°F 3 GPM per Ton for standard HVAC applications

30 Main Menu Cooling Towers by the Book Cooling Tower Selection – Example #1 Conditions: 1200 USGPM flow 95ºF T(1) entering water temperature 85ºF T(2) leaving water temperature 80ºF T(wb) wet-bulb What is capacity of this equipment?

31 Main Menu Cooling Towers by the Book Cooling Tower Selection #1 Two options 1.Tonnage = GPM x ∆T x 500/15,000 2.Tonnage = GPM/3 * * Option 2 is only on standard HVAC Applications with ∆T of 10, not applicable on industrial applications

32 Main Menu Cooling Towers by the Book Cooling Tower Selection #1 – Option #1 Tonnage = GPM x ∆T x 500/15,000 Remember Conditions Are: 1200 USGPM flow 95ºF T(1) entering water temperature 85ºF T(2) leaving water temperature 80ºF T(wb) wet-bulb Tonnage = 1200 x 10 x 500/15,000 Tonnage = 400 tons

33 Main Menu Cooling Towers by the Book Cooling Tower Selection #1 – Option #2 Tonnage = GPM/3 Remember Conditions Are: 1200 USGPM flow 95ºF T(1) entering water temperature 85ºF T(2) leaving water temperature 80ºF T(wb) wet-bulb Tonnage = 1200 GPM/3 Tonnage = 400 tons

34 Main Menu Cooling Towers by the Book Cooling Tower Selection #2 Conditions: 1200 USGPM flow 110ºF T(1) entering water temperature 85ºF T(2) leaving water temperature 80ºF T(wb) wet-bulb What is capacity of this equipment?

35 Main Menu Cooling Towers by the Book Cooling Tower Selection #2 – Option #1 Tonnage = GPM x ∆T x 500/15,000 Remember Conditions Are: 1200 USGPM flow 110ºF T(1) entering water temperature 85ºF T(2) leaving water temperature 80ºF T(wb) wet-bulb Tonnage = 1200 x 25 x 500/15,000 Tonnage = 1,000 tons

36 Main Menu Cooling Towers by the Book Cooling Tower Selection #2 – Option #2 Tonnage = GPM/3 Remember Conditions Are: 1200 USGPM flow 110ºF T(1) entering water temperature 85ºF T(2) leaving water temperature 80ºF T(wb) wet-bulb Tonnage = 1200 GPM/3 = 400 tons Wrong Answer - Option two is not applicable in non-standard HVAC applications!

37 Main Menu Materials of Construction Know your water quality…… G235 galvanized steel All Stainless steel construction Stainless hot and cold water basins Elastomeric/Polyureas (Rhino & Line X) Fiberglass/Fiberglass reinforced polyester (FRP) Electrostatic sprays or paints Wood Concrete

38 Main Menu Materials of Construction Galvanized Steel Quality G-235 Coating = 2.35 oz of zinc per square feet of steel sheet

39 Main Menu Materials of Construction Heat Transfer Wetdeck Options/History PVC CPVC Steel (galvanized or stainless) Wood Asbestos

40 Main Menu Cooling Tower Maintenance After new equipment or spring start-up inspect after 24 hours of operation

41 Main Menu Cooling Tower Maintenance…

42 Main Menu Cooling Tower Maintenance

43 Main Menu Cooling Tower Maintenance

44 Main Menu Cooling Tower Maintenance

45 Main Menu Cooling Tower Maintenance

46 Main Menu Routine Maintenance: Fan Drives Sheave Alignment Tip: Aluminum sheaves have different bushing torque requirements than cast iron sheaves. Over torquing may cause aluminum sheaves to crack. Check installation instructions or consult unit manufacturer.

47 Main Menu Routine Maintenance: Fan Drives Fan Belt Tension

48 Main Menu Routine Maintenance: Fan Motor Outside surfaces should be cleaned quarterly to ensure proper motor cooling Equipment (since ’01) utilize a Cooling Tower Duty Rated motor with permanently lubricated ball bearings and special moisture protection on the bearings, shaft, and windings

49 Main Menu Cooling Tower Life Expectancy Rule of Thumb for Tower Life Expectations Packaged Cooling Towers: Galvanized – years Stainless – years Fiberglass (non protruded)… years Field Erected Towers – Wood… years Field Erected Towers – Ceramic… years

50 Main Menu Cooling Tower Life Expectancy Rule of Thumb for Tower Life Expectations Replacement cost of a new tower is typically 2 to 3 times the cost of tower alone. Usually $200 - $400 per ton budget based on difficulty of install and materials of construction chosen. If the repair is 40% - 50% of new unit replacement cost, the retrofit is usually the best solution

51 Main Menu Cooling Tower Applications UNDERSTAND THE COOLING TOWER!

52 Main Menu To be 85° or not to be 85° That is the question.

53 Main Menu Centrifugal Chiller: 70°F ! Screw Chiller: 70°F ! Reciprocating Chiller: 70°F ! Absorption Chiller: 85°F ! Cooling Tower Applications - To Be 85° or not to be 85°?

54 Main Menu Cooling Tower Applications Operator’s job to maintain condenser water temperature between 70ºF and 85ºF. When………

55 Main Menu Cooling Tower Applications The load varies between 15% and 100% and temperature varies from 10ºF to 80ºF wet-bulb Also…….

56 Main Menu Cooling Tower Applications You will also you will be required to: Use minimum energy!!! Maintain temperature while sequencing chillers, pumps and cooling towers! Avoid frequent fan cycling!! Maintain a minimal size maintenance crew!!!!!! And if you happen to be from the North you must also Prevent Freezing!!

57 Main Menu Cooling Tower Applications Next Question… How do you manage the performance of a cooling tower? Air Management or Water Management?

58 Main Menu Cooling Tower Applications Air Management = Capacity control The cooling tower capacity is directly proportional to air flow!

59 Main Menu Cooling Tower Applications – Capacity Control Maintain Full Water Flow to Tower This allows airside capacity control mechanisms to work properly resulting in better tower control and more stable operating conditions for the chiller. What can happen if tower is controlled by water flow?

60 Main Menu Cooling Tower Applications – Capacity Control Reduced water flow may result in uneven distribution of water through the wet deck Reduces Thermal Efficiency Increases Potential Scale Build -Up Increases Potential Carry-Over/Drift Increases Potential for Motor Overload (Centrifugal Fan Units) Increases Potential Icing in Winter in North

61 Main Menu Cooling Tower Applications – Capacity Control Cooling Tower Capacity is Directly Proportional to Airflow. Airflow Modulation is the Best Method of Cooling Tower Capacity Control including… Variable Frequency Drives Two - Speed Motors Fan Cycling – no more than six per hour

62 Main Menu Cooling Tower Applications – Capacity Control Popularity of VFD’s on Pumps is up… Induced Draft Cross Flow Towers - Maybe The manufacturers of these type of towers (BAC and Marley) have provided different forms of variable water condition controls over the years including low water dams and low flow nozzles.

63 Main Menu Popularity of VFD’s on Pumps is up… Induced Draft Cross Flow Towers

64 Main Menu Cooling Tower Applications – Capacity Control Popularity of VFD’s on Pumps is up… Forced Draft Counter Flow Towers – NO (but maybe soon) Because these towers spray distribution are designed as pressurized headers there is no way to properly control low flow distribution and Should Not be considered as good candidates for water flow VFD’s!!!

65 Main Menu Large Installations Capacity Controls Multiple towers, chillers and pumps Winter operation: one chiller, one pump = one tower/cell Use automatic valves on inlet, outlet and equalizer Don’t over control – 3 to 4 steps maximum

66 Main Menu Rx for Cooling Towers

67 Main Menu Cooling Towers: Life-Reducing Conditions Contaminant fouling (sand, grit, scale, rust, etc.) Chemical imbalance Lack of maintenance Corrosion

68 Main Menu Sand, Silt, Rust, Scale, Dirt, Etc. Settled in the tower basin, required shoveling. Fouled our water treatment system. Caused excessive cartridge replacements. Plugged our spray nozzles.

69 Main Menu Source: Airborne Solids

70 Main Menu Source: Make-up Water Loss of water via evaporation Make-up water

71 Main Menu Solids Accumulation Solids load: 5 ppm (ASHRAE Std.) Tower size: 250 ton (750 gpm) 2,000 operating hours per year (approximately 40 hours per week) Example:

72 Main Menu Solids Accumulation 105,000 cubic inches of solids 5 inches deep in the tower basin

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75 Problem: Solids Accumulation

76 Main Menu Problem: Solids Accumulation

77 Main Menu Accumulation breeds bacteria growth Problem: Bacteria

78 Main Menu Accumulation breeds bacteria growth Bacteria contaminates the water Problem: Bacteria

79 Main Menu Accumulation breeds bacteria growth Bacteria contaminates the water Water mixes with the air Problem: Bacteria

80 Main Menu Accumulation breeds bacteria growth Bacteria contaminates the water Water mixes with the air Air becomes contaminated Problem: Bacteria

81 Main Menu What bacteria can be found in a typical cooling tower??? Problem: Bacteria

82 Main Menu What bacteria can be found in a typical cooling tower??? Legionella Tuberculosis Whooping cough Strep pneumonia Staph pneumonia Problem: Bacteria

83 Main Menu Keep cooling tower exhaust away from building air intake Use an effective biocide Wear protective devices when cleaning or working in a tower Keep suspended solids and organics out of cooling water loops ASHRAE Guidelines

84 Main Menu Problem: Solids-Fouling

85 Main Menu Problem: Solids-Fouling

86 Main Menu Problem: Fouling

87 Main Menu Problem: Fouling

88 Main Menu Problem: Fouling

89 Main Menu Problem: Fouling in the tower fill

90 Main Menu Solution Techniques Full Stream Make-up Water Side Stream Basin Cleaning

91 Main Menu Solution: Full-Stream Protection

92 Main Menu Solution: Side-Stream Protection

93 Main Menu Solution: Basin Sweeper Systems

94 Main Menu Sweeper System: Sample Configuration

95 Main Menu Sweeper Nozzle: Pattern of Influence

96 Main Menu

97 What kind of filter?

98 Main Menu Filter Choices Separators Cartridge Filters Strainers Screens Sand Filters

99 Main Menu Screens,Bags, Cartridges

100 Main Menu Sand Filter: How it works

101 Main Menu Sand Filter: Backwash Process

102 Main Menu Centrifugal Action Separator

103 Main Menu Filtration Selection Criteria Particle size removal Flow range Pressure loss Maintenance requirements Liquid loss Solids handling Space requirements Engineering & technical support

104 Main MenuQuestions?


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