Engineered Systems - March 2009 - (Page 39)

www.dedietrichboilers.com Basics For Absorption Chillers 0.1 ATM Steam fired Generator 5 1 Steam Condensor High temp. Generator Pump Chilled water out Cooling water out 8 Steam 3 6 0.01 ATM Evaporator 7 2 High temp. Hx Comp. Hx Low temp. Hx Absorber Evap. spray pump Chilled water in As the Boiler Should Be!!! GAS 230 and GAS 310 ECO SERIES 4 Absorber spray pump Purge pump Cooling water in Generator pump FIGURE 2. Double-effect absorption refrigeration cycle. pleting the absorber cycle. • Double-effect absorption chiller. The double-effect chiller condensing (condenser), expansion (expansion pipe), evaporation (evaporator), and absorption (absorber) steps are the same as the single-effect chiller. The double-effect chiller has an additional generator/concentrator step that improves the overall efficiency of the chiller (Figure 2). The following is a description of the double-effect chiller generator/concentration: • Generator/concentrator. The lithium-bromide solution enters the low-temperature generator/concentrator and is heated by the high temperature generator/concentrator vaporized refrigerant, raising the lithiumbromide solution to a temperature where the liquid refrigerant vaporizes and travels to the condenser. The high-temperature vaporized refrigerant discharges into the condenser. The concentrated lithium bromide solution takes one of two paths. One path has the lithium-bromide solution flowing down to the absorber, being mixed with higher concentrated lithium-bromide solution coming from the high temperature generator/ concentrator, heated, and discharged into absorber. The other path has the lithiumbromide solution being heated and pumped to the high temperature generator/concentrator where steam, hot water, or direct- fired heating is applied to raise the lithium bromide solution to a temperature where the liquid refrigerant vaporizes and travels to the condenser. The highly concentrated lithium bromide solution is mixed with the concentrated lithium bromide going to the absorber. CHILLER PERFORMANCE STANDARD The primary absorption chiller performance standard is ARI Standard 560 (2000 Standard for Absorption Water Chilling and Water Heating Packages). ARI Standard 560 applies to water cooled single-effect steam chillers, water cooled single-effect hot water chillers, water cooled double-effect steam chillers, water cooled double-effect hot water chillers, and water cooled double-effect direct-fired chillers. This standard provides testing standard conditions, rating requirements, minimum data requirements for published ratings, and integrated part load value (IPLV) or non-standard part load value (NPLV). For performing the IPLV testing, ARI Standard 560 has established standard conditions for absorption chillers including: • Entering condenser water temperature: 85° • Condenser water flow rate: 3.6 gpm/ton (single-effect indirect fired) • 4.0 gpm/ton (double-effect indirect fired, double-effect direct-fired) • Condenser water-side fouling factor: 0.00025 • Evaporator leaving water temperature: 44° • Evaporator water flow rate: 2.4 gpm/ton CONDENSING BOILERS c 99.9% Thermal Efficiency c Cast Aluminum Heat Exchanger c SCAQMD Certified to <20 ppm NOx c 9 Models Ranging from 300 to 2,000 MBH c 100 PSI Working Pressure c Lowest Pressure Drops c No Minimum Return Temperature c Best Warranty in the Industry c Noise Rating <60dBa c In Stock, Next Day Delivery!! WHEN YOU TH!NK BOILERS TH!NK Input 219 at www.esmagazine.com/instantproductinfo w w w. esmag a zin e. c o m 39 http://www.dedietrichboilers.com http://www.dedietrichboilers.com http://www.esmagazine.com/instantproductinfo http://www.esmagazine.com

Table of Contents Feed for the Digital Edition of Engineered Systems - March 2009

Engineered Systems - March 2009 Contents Editor’s Note Back2Basics Case In Point Commissioning Building Automation HVACR Designer Tips Application Checklist Teaching An Old School New Tricks Basics For Absorption Chillers A New Haven For Sustainable Schools Glossary Classifieds Advertiser Index Tomorrow’s Environment

Engineered Systems - March 2009

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