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Kỹ Thuật - Công Nghệ - Kỹ thuật - Điện - Điện tử - Viễn thông a Trane Engineers Newsletter Live Cooling Towers and Condenser Water Systems: Design and Operation 2005 2018 Trane a business of Ingersoll Rand. All rights reserved Trane, in proposing these system design and application concepts, assumes no responsibility for the performance or desirability of any resulting system design. Design of the HVAC system is the prerogative and responsibility of the engineering professional. 1 2005 American Standard Inc. Cooling Towers and Condenser Water Systems Design and Operation an Engineers Newsletter Live telecast 2005 American Standard Inc. Today’s TopicsToday’s Topics Fundamentals Chiller–tower interaction Cooling-tower terminology, operation Design conditions Cooling-tower control options System optimization Answers to your questions a Trane Engineers Newsletter Live Cooling Towers and Condenser Water Systems: Design and Operation 2005 2018 Trane a business of Ingersoll Rand. All rights reserved Trane, in proposing these system design and application concepts, assumes no responsibility for the performance or desirability of any resulting system design. Design of the HVAC system is the prerogative and responsibility of the engineering professional. 2 2005 American Standard Inc. Today’s PresentersToday’s Presenters Lee Cline systems marketing engineer Dave Guckelberger applications engineer Mick Schwedler applications engineer 2005 American Standard Inc. Cooling Towers and Condenser Water Systems Design and Operation Cooling tower fundamentals a Trane Engineers Newsletter Live Cooling Towers and Condenser Water Systems: Design and Operation 2005 2018 Trane a business of Ingersoll Rand. All rights reserved Trane, in proposing these system design and application concepts, assumes no responsibility for the performance or desirability of any resulting system design. Design of the HVAC system is the prerogative and responsibility of the engineering professional. 3 2005 American Standard Inc. Refrigeration Cycle Refrigeration Cycle 2-stage compressor evaporator condenser economizer expansion device expansion device 2005 American Standard Inc. Pressure–Enthalpy (p-h ) Chart Pressure–Enthalpy (p-h ) Chart enthalpy subcooled liquid subcooled liquid liquid + vapor mix pressure superheated vaporB 92.4 Btulb15.5 Btulb A 5 psia a Trane Engineers Newsletter Live Cooling Towers and Condenser Water Systems: Design and Operation 2005 2018 Trane a business of Ingersoll Rand. All rights reserved Trane, in proposing these system design and application concepts, assumes no responsibility for the performance or desirability of any resulting system design. Design of the HVAC system is the prerogative and responsibility of the engineering professional. 4 2005 American Standard Inc. 2-stage centrifugal chiller Refrigeration Cycle 2-stage centrifugal chiller Refrigeration Cycle enthalpy pressure expansion devices evaporator economizer condenser 9 8 7 6 5 Pe 1 3 P 1 2-stage compressor 2 Pc 4 2005 American Standard Inc. 2-stage centrifugal chiller Refrigeration Cycle 2-stage centrifugal chiller Refrigeration Cycle enthalpy pressure expansion devices evaporator economizer P c condenser Pe P 1 2-stage compressor 4 1 4'''' a Trane Engineers Newsletter Live Cooling Towers and Condenser Water Systems: Design and Operation 2005 2018 Trane a business of Ingersoll Rand. All rights reserved Trane, in proposing these system design and application concepts, assumes no responsibility for the performance or desirability of any resulting system design. Design of the HVAC system is the prerogative and responsibility of the engineering professional. 5 2005 American Standard Inc. chiller–tower interaction Heat Rejection chiller–tower interaction Heat Rejection Tower determines return condenser water temperature Chiller determines required heat rejection rate of tower Hermetic motor: 100 of electrical input Open motor: electrical input × motor efficiency Evaporator load + Compressor energy 2005 American Standard Inc. chiller–tower interaction Heat Rejection, Q chiller–tower interaction Heat Rejection, Q Q = evaporator load + input energy or Q = evaporator load × (1 + 1COP) a Trane Engineers Newsletter Live Cooling Towers and Condenser Water Systems: Design and Operation 2005 2018 Trane a business of Ingersoll Rand. All rights reserved Trane, in proposing these system design and application concepts, assumes no responsibility for the performance or desirability of any resulting system design. Design of the HVAC system is the prerogative and responsibility of the engineering professional. 6 2005 American Standard Inc. electric chiller Heat Rejection Example electric chiller Heat Rejection Example For 1 ton of evaporator load: Q = 12,000 Btuh × (1 + 16.10) = 12,000 Btuh × (1 + 0.16) = 13,967 Btuh 2005 American Standard Inc. For 1 ton of evaporator load, condenser water temperature rises … … 9.3°F at 3 gpmton T = 13,967 (500 × 3) = 9.3F electric chiller Heat Rejection Example electric chiller Heat Rejection Example … 14.0°F at 2 gpmton T = 14,000 (500 × 2) = 14.0F T = Q (Btuh) (500 × gpm) a Trane Engineers Newsletter Live Cooling Towers and Condenser Water Systems: Design and Operation 2005 2018 Trane a business of Ingersoll Rand. All rights reserved Trane, in proposing these system design and application concepts, assumes no responsibility for the performance or desirability of any resulting system design. Design of the HVAC system is the prerogative and responsibility of the engineering professional. 7 2005 American Standard Inc. chiller–tower interaction Heat Rejection chiller–tower interaction Heat Rejection Condenser water warms in proportion to heat rejection and condenser water flow rate Condenser pressure rises with condenser temperature Compressor work increases as condenser pressure rises 2005 American Standard Inc. Cooling Tower Cooling Tower “Heat transfer device, often tower-like, in which atmospheric air cools warm water, generally by direct contact (evaporation).” ASHRAE Terminology of HVAC R a Trane Engineers Newsletter Live Cooling Towers and Condenser Water Systems: Design and Operation 2005 2018 Trane a business of Ingersoll Rand. All rights reserved Trane, in proposing these system design and application concepts, assumes no responsibility for the performance or desirability of any resulting system design. Design of the HVAC system is the prerogative and responsibility of the engineering professional. 8 2005 American Standard Inc. cooling tower Components cooling tower Components sprays sump sump outdoor air louvers hot water fill to condenser cold water from condenser propeller fan 2005 American Standard Inc. cooling tower Performance Factors cooling tower Performance Factors Ambient wet-bulb temperature drives tower design and selection ASHRAE Fundamentals Handbook, “Evaporation” 0.4 value is most conservative … exceeded ~35 hoursyear a Trane Engineers Newsletter Live Cooling Towers and Condenser Water Systems: Design and Operation 2005 2018 Trane a business of Ingersoll Rand. All rights reserved Trane, in proposing these system design and application concepts, assumes no responsibility for the performance or desirability of any resulting system design. Design of the HVAC system is the prerogative and responsibility of the engineering professional. 9 2005 American Standard Inc. cooling tower Performance Factors cooling tower Performance Factors hot water temperature cold water temperature ambient wet bulb tower flow rate range approach 2005 American Standard Inc. cooling tower certification CTI Performance Limits cooling tower certification CTI Performance Limits hot water < 125°F cold water temperature ambient 60°F–90°F WB Cooling Technology Institute (CTI) may certify tower performance range > 4°F approach > 5°F a Trane Engineers Newsletter Live Cooling Towers and Condenser Water Systems: Design and Operation 2005 2018 Trane a business of Ingersoll Rand. All rights reserved Trane, in proposing these system design and application concepts, assumes no responsibility for the performance or desirability of any resulting system design. Design of the HVAC system is the prerogative and responsibility of the engineering professional. 10 2005 American Standard Inc. example at standard rating conditions Tower Performance example at standard rating conditions Tower Performance Flow rate, gpm 1500 Design WB, °F 78 Approach, °F 7 Hot water, °F 94.3 Cold water, °F 85 Fan power, hp 40 Base condition 2005 American Standard Inc. example at standard rating conditions Same Tower, Lower Flow example at standard rating conditions Same Tower, Lower Flow 96°F hot water 82°F cold water 78°F WB design ambient range = 14°F approach = 4°F 2 gpmton a Trane Engineers Newsletter Live Cooling Towers and Condenser Water Systems: Design and Operation 2005 2018 Trane a business of Ingersoll Rand. All rights reserved Trane, in proposing these system design and application concepts, assumes no responsibility for the performance or desirability of any resulting system design. Design of the HVAC system is the prerogative and responsibility of the engineering professional. 11 2005 American Standard Inc. Base Same tower, condition lower flow example at standard rating conditions Tower Performance example at standard rating conditions Tower Performance Flow rate, gpm 1500 1000 Design WB, °F 78 78 Approach, °F 7 4 Hot water, °F 94.3 96 Cold water, °F 85 82 Fan power, hp 40 40 2005 American Standard Inc. example at standard rating conditions Same Approach, Lower Flow example at standard rating conditions Same Approach, Lower Flow 99°F hot water 85°F cold water 78°F WB design ambient range = 14°F approach = 7°F 2 gpmton a Trane Engineers Newsletter Live Cooling Towers and Condenser Water Systems: Design and Operation 2005 2018 Trane a business of Ingersoll Rand. All rights reserved Trane, in proposing these system design and application concepts, assumes no responsibility for the performance or desirability of any resulting system design. Design of the HVAC system is the prerogative and responsibility of the engineering professional. 12 2005 American Standard Inc. Flow rate, gpm 1500 1000 1000 Design WB, °F 78 78 78 Approach, °F 7 4 7 Hot water, °F 94.3 96 99 Cold water, °F 85 82 85 Fan power, hp 40 40 25 example at standard rating conditions Tower Performance example at standard rating conditions Tower Performance Base Same tower, Smaller tower, condition lower flow lower flow 2005 American Standard Inc. cooling tower performance factors Approach and Range cooling tower performance factors Approach and Range ambient wet bulb, °F 0.0 4.0 8.0 12.0 16.0 50 60 70 80 tower approach, deg 100 load 50 load approach = 4 approach = 7 a Trane Engineers Newsletter Live Cooling Towers and Condenser Water Systems: Design and Operation 2005 2018 Trane a business of Ingersoll Rand. All rights reserved Trane, in proposing these system design and application concepts, assumes no responsibility for the performance or desirability of any resulting system design. Design of the HVAC system is the prerogative and responsibility of the engineering professional. 13 2005 American Standard Inc. ambient wet bulb, °F 0.0 4.0 8.0 12.0 16.0 50 60 70 80 tower approach, deg 100 load 50 load cooling tower performance factors Approach and Wet Bulb cooling tower performance factors Approach and Wet Bulb approach = 7 approach = 16 2005 American Standard Inc. ambient wet bulb, °F 0.0 4.0 8.0 12.0 16.0 50 60 70 80 tower approach, deg 100 load 50 load approach = 4 approach = 9 cooling tower performance factors Approach and Wet Bulb cooling tower performance factors Approach and Wet Bulb a Trane Engineers Newsletter Live Cooling Towers and Condenser Water Systems: Design and Operation 2005 2018 Trane a business of Ingersoll Rand. All rights reserved Trane, in proposing these system design and application concepts, assumes no responsibility for the performance or desirability of any resulting system design. Design of the HVAC system is the prerogative and responsibility of the engineering professional. 14 2005 American Standard Inc. Cooling Towers and Condenser Water Systems Design and Operation Design conditions 2005 American Standard Inc. a design issue Flow Rates a design issue Flow Rates Past rule of thumb: 3 gpmton 10° F ΔT for older, less efficient chillers ~9°F ΔT for currently produced chillers Today’s design advice Reduce flow rates Increase temperature differences a Trane Engineers Newsletter Live Cooling Towers and Condenser Water Systems: Design and Operation 2005 2018 Trane a business of Ingersoll Rand. All rights reserved Trane, in proposing these system design and application concepts, assumes no responsibility for the performance or desirability of any resulting system design. Design of the HVAC system is the prerogative and responsibility of the engineering professional. 15 2005 American Standard Inc. increase T, reduce flow rate Condenser Water increase T, reduce flow rate Condenser Water Industry advisor Pacific Gas and Electric CoolTools™ Recommendation 10°–15°F T single stage 12°–18°F T multistage or positive displacement Kelly and Chan 14.2°F T for 3.6–8.3 energy savings in various climates ASHRAE Green Guide 12°–18°F T 2005 American Standard Inc. a history of Chiller Performance a history of Chiller Performance 8.0 ASHRAE Standard 90 chiller efficiency, COP 6.0 4.0 2.0 0.0 NBI “best” available 90-75 (1977) 90-75 (1980) 90.1-89 90.1-99 centrifugal >600 tons screw 150-300 tons scroll