Evaporative-Cooled vs. Air-Cooled Chillers: Kirtland AFB Case Study www.amec.com DISCUSSION TOPICS  Brief Overview of Air-Cooled and Evaporative-Cooled Condenser Technologies  Pros and Cons  Scope and Results of Kirtland AFB Study  Conclusions and Recommendations  Q&A 2 AIR-COOLED CONDENSER BASICS  Refrigerant hot gas is cooled and condensed in Air-to-Refrigerant Heat Exchanger (coil).  Air-Cooled Condenser efficiency depends on ambient air dry bulb temperature, i.e. the higher OAT is, the more power is required to compress hot gas in order to condense it into liquid. 3 EVAPORATIVE-COOLED CONDENSER BASICS  Treated water is sprayed over condenser coil. Part of water is evaporated thus lowering surface temperature of the condenser and the air drawn across it.  Remaining water is collected in drain pan and recirculated back to sprayer.  Make-up city water is added to replace evaporated water.  Refrigeration system efficiency is increased by 25-50% compared to air-cooled due to lower vapor compression pressure, thus reducing compressor‘s energy. 4 AIR-COOLED AND EVAPORATIVE-COOLED CONDENSER COMPARISON  PROS OF AIR-COOLED vs. EVAPORATIVE-COOLED:  Smaller cabinet  Lighter weight  No condenser water piping and treatment  Lower equipment cost  Lower maintenance cost  No water consumption for condenser operation  PROS OF EVAPORATIVE-COOLED vs. AIR-COOLED: 20-40% lower electrical consumption of the chiller Quieter operation 5 KIRTLAND AFB ENERGY STUDY OBJECTIVE:  Increase the energy efficiency of existing facilities on various Air Force Bases in order to reduce the building annual operating cost. STUDY SCOPE:  Evaluate life cycle costs of replacement of existing Air-Cooled Chillers with Evaporative-Cooled Chillers at seven (7) buildings.  Life Cycle Cost Analysis compared costs associated with Evaporative-Cooled Chillers against Status Quo (air-cooled chillers), and included: Capital Cost Estimate (material and labor) at +/-30% accuracy. Maintenance Cost analysis. Operating Cost Analysis (electricity and water). 6 KIRTLAND AFB ENERGY STUDY RESULTS CAPITAL COST COMPARISON FOR EVAPORATIVE AND AIR- COOLED CHILLERS BUILDING CHILLER EVAPORATIVE-COOLED AIR-COOLED NO. TONNAGE CHILLERS CHILLERS 1005 60 $178,000 $74,000 20140 60 $178,000 $74,000 322 70 $204,000 $84,000 1017 90 $262,000 $113,000 20222 100 $279,000 $130,000 20361 165 $389,000 $176,000 472 250 $471,500 $235,000 7 KIRTLAND AFB ENERGY STUDY RESULTS ANNUAL OPERATING COST COMPARISON FOR EVAPORATIVE AND AIR-COOLED CHILLERS ELECTRICITY CITY WATER AND CHILLER MAINTENANCE KWh x 1,000 / COST SEWER TONS (chiller only) (chiller only) (chiller only) EVAP- AIR- EVAP- AIR- EVAP- AIR-COOLED COOLED COOLED COOLED COOLED COOLED 60 49 / $3,920 28 / $2,240 $0 $323 $1,600 $2,000 60 49 / $3,920 28 / $2,240 $0 $323 $1,600 $2,000 70 56 / $4,480 30 / $2,400 $0 $353 $1,600 $2,000 90 34 / $2,720 16 / $1,280 $0 $196 $2,400 $3,200 100 66 / $5,280 39 / $3,120 $0 $463 $2,400 $3,200 165 102 / $8,160 56 / $4,480 $0 $665 $2,400 $3,200 250 200 / $16,000 108 / $8,640 $0 $1,260 $2,400 $3,200 8 KIRTLAND AFB ENERGY STUDY RESULTS 10- YEAR LIFE CYCLE COST COMPARISON FOR EVAPORATIVE AND AIR-COOLED CHILLERS LCC OF COST RATIO OF LCC OF AIR- BLDG CHILLER EVAPORATIVE- AIR-COOLED / COOLED NO. TONNAGE COOLED EVAP-COOLED CHILLERS CHILLERS CHILLERS 1005 60 $301,000 $201,000 67% 20140 60 $301,000 $201,000 67% 322 70 $350,000 $233,000 62% 1017 90 $462,000 $293,000 64% 20222 100 $513,000 $335,000 65% 20361 165 $757,000 $557,000 74% 472 250 $1,386,000 $1,191,000 86% 9 KIRTLAND AFB ENERGY STUDY RESULTS 10- YEAR LIFE CYCLE COST COMPARISON FOR EVAPORATIVE AND AIR-COOLED CHILLERS 10