Integrated Chiller Retrofit Case Studies

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					Overview of Collected Integrated
 Chiller Retrofit Case Studies
            Dr. Lisa Gartland
   (510) 595-7674, positivenergy@california.com
 Integrated Chiller Retrofit Case Studies

• Cool $ense workshops have been held
  around the country
  – Boston, Denver, San Diego, Kansas City,
    Atlanta, and Washington D.C.
• Case studies collected in each region
  – most are highly integrated retrofits
  – all exemplify aspects of the Cool $ense message
Integrated Chiller Retrofit Case Studies

 • Overview of collected case studies
   –   chiller retrofit/replacement examples
   –   cooling system improvement example
   –   building load reduction example
   –   integrated retrofit economics
   –   how retrofits can be improved
 • Details of individual case studies are
   on the Cool $ense web site
   – http://eetd.lbl.gov/CoolSense
   Integrated Chiller Retrofit Case Studies
           Chiller Retrofits/Replacements

• Most of my case studies start with and keep
  electric centrifugal chillers
  – don’t often switch to gas-fired or absorption chillers
• Significant efficiency gains
  – original full-load efficiencies of 0.72 to 0.90 kW/ton
  – replacement efficiencies of 0.48 to 0.65 kW/ton
• Total capacity stays about the same
  – 260 tons/100,000 square feet “before”
    245 tons/100,000 square feet “after”
     Integrated Chiller Retrofit Case Studies
                     Chiller Retrofit Example

     Lawrence Street Center
          Denver, CO
       office space
       radio stations
       140,000 square feet
       14 stories
       built in 1982
         Chiller “Before”
•   400 ton electric chiller
•   R-11 refrigerant
•   0.72 kW/ton efficiency
•   Less than 15 years old
•   Operating at 60% capacity
Integrated Chiller Retrofit Case Studies
  Lawrence Street Center - Chiller Retrofit

                       Chiller “After”
• Driveline retrofit, replaces the driveline, including
  starter, motor, compressor, purge unit and controls
• Kept old heat exchanger
   – checked condition of shells & tubes condition with
      eddy current testing of condenser & evaporator
• Capacity reduced from 400 tons to 290 tons
• Full load efficiency of 0.59 kW/ton

        Retrofit     Rebate        Annual      Payback
         Cost                      Energy       Period
                                   Savings      (years)
        $ 94,000     $ 32,000      $ 12,500       4.96
      Integrated Chiller Retrofit Case Studies
                   Chiller Replacement Example

Kansas City
International
Airport

3 terminals, 1 office
1,000,000 square feet
2 stories
built in 1970
                                 Chiller “Before”
    • Two 2750-ton electric chillers
        – installed in 1970, estimated efficiency 0.85 - 0.9 kW/ton at full load
        – R-12 refrigerant, no refrigerant containment system
    • Never run the second chiller & often running at part-loads
    • 48-49°F discharge water temperatures, not meeting design 42°F
 Integrated Chiller Retrofit Case Studies
Kansas City Intl Airport - Chiller Replacement
                              Chiller “After”
• Three 1500-ton electric chillers
    –   more flexible staging capability than with the 2 larger chillers
    –   R-134a refrigerant
    –   efficiency of 0.65 kW/ton at full load
    –   saving about 0.25 kW/ton
• Running closer to full-load capacities for higher efficiencies
• Meeting 42°F design water discharge temperature

                                Purchase &       Annual          Payback
                                Installation     Energy           Period
                                  Cost ($)      Savings ($)       (years)
        New Chillers             $800,000        $63,500            12.6
  Integrated Chiller Retrofit Case Studies
           Cooling System Improvements

• Most common cooling system improvements
  –   replacement of cooling towers
  –   new, more efficient fans, pumps & motors
  –   addition of economizer or evaporative cooling
  –   new air handler units with variable volumes
  –   automated control systems to integrate building
      operation with outside conditions and indoor loads
• Rarer cooling system improvements
  – thermal storage
  – heat recovery systems
          Integrated Chiller Retrofit Case Studies
                    Cooling System Improvements

Rhode Island Hospital Trust
      Rhode Island

    office space
    computer operations
    140,000 square feet
    1 story
    built in 1983
                                  “Before” Scenario
         •   Need to reduce demand and on-peak electricity consumption
         •   One 275 ton electric chiller & 208 tons of rooftop units
         •   CFC-11 refrigerant, 0.75 kW/ton efficiency
         •   Building expanding by 50%, or 70,000 square feet
         •   Plenty of room for equipment
 Integrated Chiller Retrofit Case Studies
      Rhode Island Hospital Trust Building

• Ice storage system
   – 390 ton brine chiller, three 761 ton-hour ice banks
   – create ice at night, cooling load diverted to ice banks during day
• 390 ton high efficiency brine chiller
   – meets summer loads in building and computer room
• Rooftop units originally cooled computer room all year
   – retrofit with chilled water coils & hooked up to heat exchanger
   – original rooftop units kept for backup capability
• Added variable speed drives, high efficiency motors, EMCS
• T-8 fluorescent lights used with occupancy sensors

          Project        Rebate     Annual Energy    Payback
            Cost                       Savings        Period
         $1,200,000     $ 575,000     $ 196,000      3.2 years
 Integrated Chiller Retrofit Case Studies
             Building Load Reductions

• Lighting Improvements
  –   most projects add T-8 lamps & electronic ballasts
  –   fewer use low energy incandescents & exit signs
  –   occupancy sensors could be used more often
  –   additional daylighting rarely introduced and/or
      compensated for by lighting sensors
• Wall and window upgrades to reduce loads
  – low-emissivity films used fairly commonly
  – insulation is rarely increased
  – surface reflectivities never increased
      Integrated Chiller Retrofit Case Studies
              Building Load Reduction Example

        New York Life Building
          Kansas City, MO

           office space
           220,000 square feet
           12 stories
           built in 1888
           Envelope Measures
• New energy-efficient windows
   – double-pane, low-e, insulated frames
   – custom-made operable windows
• Exterior masonry walls
   – R-11 fiberglass insulation added
• New roof with R-20 insulation
• 5-7 year paybacks
  Integrated Chiller Retrofit Case Studies
      Kansas City’s New York Life Building
                          Lighting Measures
• Overhead lighting
   – T8 Fluorescent tubes
   – solid-state, low-energy, dimmable ballasts
• Daylighting
   – ceilings slope down from windows to reflect light into interior
   – interior light shelves, light reflective colors
• Computer-controlled system
   – adjust overhead light levels according to the amount of daylight
   – occupancy sensors turn off lights when no one is present
• 3-4 year paybacks

•Saved $0.50 to $0.80 per square foot
•Comfortable, modern office building with historic character
   Integrated Chiller Retrofit Case Studies
        Integrated Retrofit Economics Example

Worcester Polytechnic Institute
       Worcester, MA

Gordon Library & Fuller Laboratory
library and computer laboratory
128,700 square feet total
4 & 6 stories
built in 1958 & 1985

    Integrated Retrofit     Cost       Utility  Annual       Payback
        M easures            ( $)    Incentive  Energy        Period
                                        ( $)   Savings( $)    ( years)
       New Chiller         110,240       4,250      6,430         16.5
      AHU Controls           6,900       4,430        560           4.4
  EM S plus VSD pumps       75,000       6,670      4,650         14.7
    Lighting Retrofits     159,600      43,940    38,710            3.0
  CoolingT ower/HeatEx     221,400    141,280     21,070            3.8
          T otal          $573,140   $200,570    $71,420            5.2
Integrated Chiller Retrofit Case Studies
Improving Integrated Retrofits - Chiller Sizing

                      New 600 ton electric centrifugal
                      chiller, about to be installed
                      in Boston’s Hurley Building.
                         This chiller replaces an equal
                         capacity chiller, despite lighting
                         load reductions and increased
                         system efficiencies!

                       • Know your building loads both
                         before & after retrofit work!!
                       • Downsize, rightsize or stage
                         your chillers to most efficiently
                         meet these loads!
   Integrated Chiller Retrofit Case Studies
Improving Integrated Retrofits - Higher Motivations

    • Most common motivations
      –   CFC phaseouts
      –   equipment age or imminent failure
      –   high utility bills or increasing fuel costs
      –   rebate programs
    • Motivations leading to the “best” retrofits
      – comfort or indoor air quality problems
      – environmental concerns or energy efficiency goals
      – extensive building renovation
     Integrated Chiller Retrofit Case Studies
                     Set Challenging Goals

Green Building
San Diego, CA

office space
73,000 square feet
3 stories
built in 1981


• Goal of four year payback in terms of energy savings
• High levels of energy & environmental performance
  – use less than 9 kWh per square foot annually
  – use environmentally friendlier materials
• Model for sustainable building practices in San Diego
  Integrated Chiller Retrofit Case Studies
           Green Building’s Goals Were Met
                                   Purchase &         Total    Payback
                                 Installation Cost   Savings    Period
                                         ($)            ($)     (years)
 High Efficiency Heat Pumps           15,000          13,700      1.1
   New Lobby Heat Pumps               10,250          1,400       7.3
    New Cooling Towers                57,000          1,650      34.5
      VSDs on Pumps                   18,100          14,900      1.2
Reduced Supply & Outside Air              0           7,100       0.0
   Light Fixture Revisions            40,100          13,100      3.1
      Lighting Controls               45,500          6,700       6.8
 Occupancy Sensor Interlock            5,100          2,100       2.4
  CRT Occupancy Sensors               21,000          5,900       3.6
        Window Films                  46,000          3,850      11.9
Panels in Sloped Glass Offices         9,700           750       12.9
             Total                   $267,750        $71,150      3.8

    •Used 8.0 kWh/sq.ft, meeting 9kWh/sq.ft. goal
Integrated Chiller Retrofit Case Studies
                    Summary


• Integrated retrofit projects CAN combine
  – high energy efficiency
  – innovative technology for chillers, thermal
    storage, air handling, lighting, etc.
  – financial viability
• When it’s time to replace your chiller
  – set high goals for your building, then meet them!

				
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