Overview of Collected Integrated Chiller Retrofit Case Studies Dr. Lisa Gartland (510) 595-7674, firstname.lastname@example.org 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!