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Projects Updates for Reduce Cooling Tower and Chiller Plant Water Use

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  2. Illini Union cooling towers removed

    Associated Project(s): 
    Reduce Cooling Tower and Chiller Plant Water Use

    The Illini Union has demolished its old cooling towers for HVAC in the past 15 years, and recently demolished the old evaporator cooling system for the refrigeration chilling water in 2017. Almost all of our HVAC is now on DDC, with the exception of AHU’s 1, 2, & 3 in the South Building attic, and AHU-21 in the North Building NW subbasement.

  3. OMA representatives review stand-alone cooling towers

    Associated Project(s): 
    Reduce Cooling Tower and Chiller Plant Water Use

    Water Station Foreman, Shawn Young, indicated today that there are two remaining stand-alone cooling towers on campus buildings maintained by F&S: Temple Buell Hall and the Personnel Services Building.  One of these (Personnel) is scheduled to be added to the central chilled water loop in 2020, according to the Utilities Energy Production and Distribution Master Plan.  Base on that discussion, Morgan Johnston will be following up with the Water SWATeam to let them know that because there are so few remaining stand-alone cooling towers, this is not a high-priority item to pursue.

  6. Water & Stormwater SWAT Meeting Minutes 3/30/2017

    Associated Project(s): 
    BIF Greywater Pipe System
    Reduce Cooling Tower and Chiller Plant Water Use
    Water Audit / Inventory
    Water and Stormwater SWATeam
    Agriculture, Land Use, Food, and Sequestration (ALUFS) SWATeam

    Updates and discussion of greywater meter, greywater design standards, cooling tower cycles of concentration, water use dashboard, and student outreach. 

    Attached Files: 

  7. Water Use and Cycles of Concentration (COC) in a cooling tower

    Associated Project(s): 
    Reduce Cooling Tower and Chiller Plant Water Use
    Land and Water iCAP Team

    Below is information provided by Jeremy Overmann, B.S. Ch. E., Water Treatment Specialist, on the water use and cycles of concentration (COC) in a cooling tower, as requested after a Land and Water SWAT meeting. 

    "

    Water SWAT members,

     

    Here is some more information regarding the cooling tower discussion at today’s meeting.

     

    This first graph shows how much water a typical 100 ton Cooling Tower uses per hour, and how this changes when the tower is operated at various Cycles of Concentration (COC)

    NOTE:  a 1 ton cooling tower can remove 15,000 BTU/hr of heat.

     

    2Q==

     

    Most standard chemically treated Cooling Towers use unsoftened water and operate between 4 – 6 COC, depending on the source water quality (also called Make-Up water) and the efficacy of the chemical treatment program.

    As COC increases, the potential for formation of calcium scale (and possibly other types of scale) increases.  Scale deposits reduce the energy efficiency of the chiller and the cooling tower, and result in the need for labor intensive cleaning to remove the scale.

     

     

    The following table shows the relationship between volume of Cooling Tower blowdown (bleed), blowdown rate (% bleed), COC, and total water usage.

    Cycles of Concentration is controlled by choosing the rate of blowdown.  This is done by controlling the blowdown (bleed) valve at the bottom of the tower.

     

    COC

    BLOWDOWN

    TOTAL USAGE (Makeup)
     

    Gallons

    Percent

    Gallons

    Percent

    1.5

    10,000

    100%

    15,000

    100%

    2

    5000

    50%

    10,000

    66%

    3

    2500

    25%

    7500

    50%

    4

    1667

    17%

    6667

    44%

    5

    1250

    13%

    6250

    42%

    6

    1000

    10%

    6000

    40%

    7

    833

    8%

    5833

    39%

    8

    714

    7%

    5714

    38%

    Note: Evaporation = 5000 Gallons

     

     

     

    In a “Zero” blowdown cooling tower, softened water is used, and cycles of concentration ranges from 20 – 100 or higher.  To achieve proper water chemistry to provide corrosion protection, usually need to operate at > 20 COC. 

    During the Champaign Regional Office Building study, the highest COC achieved was 51.  The blowdown valve is turned off, however some water is lost from leaks in the tower, and from droplets of water that escape with the air that is drawn through the tower.

     

    COC

    BLOWDOWN

    TOTAL USAGE (Makeup)
     

    Gallons

    Percent

    Gallons

    Percent

    1.5

    10,000

    100%

    15,000

    100%

    5

    1250

    13%

    6250

    42%

    10

    555

    6%

    5550

    37%

    25

    208

    2%

    5208

    35%

    50

    102

    1%

    5102

    34%

    75

    66

    0.7%

    5066

    34%

    100

    51

    0.5%

    5051

    34%

    200

    25

    0.3%

    5025

    34%

    Note: Evaporation = 5000 Gallons

     

    "

     

  9. iWG Meeting Notes from Jan. 27, 2017

    Associated Project(s): 
    iCAP Working Group (iWG)
    Reduce Cooling Tower and Chiller Plant Water Use
    Indoor Bike Parking
    Green Lab Program
    Formal Sustainability Procedures

    The iCAP Working Group met and discussed the following agenda items.  Meeting notes are attached.

    1. Brief iCAP Portal overview by Morgan
    2. Discuss any updates to Water002, Cooling Tower Increase COC
    3. Discuss Trans008, Bike Parking in Ramps
    4. Discuss updates to Econs004, Green Labs Coordinator
    5. Consider issues with recommendation process and view recommendation tracker

    Attached Files: 

  10. Water & Stormwater SWATeam Meeting Minutes 2/2/2017

    Associated Project(s): 
    Water and Stormwater SWATeam
    BIF Greywater Pipe System
    Reduce Cooling Tower and Chiller Plant Water Use
    Obtain and Publicize Water Data
    Use of Non-Potable Water (such as Greywater)

    Review of pending recommendations: BIF Greywater, Increase Cooling Tower COC, Design Center Greywater Piping. Discussion on possible edits to the SWAT/iWG process. Student members will submit proposal to Student Sustainability Commision for apermanent meter to measure BIF greywater use. The Water SWATeam will meet every other week and will have a joint meeting with the Agriculture, Land Use, Food, and Sequestration (ALUFS) SWATeam this semester. 

    Attached Files: