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Air Conditioning and Mechanical Ventilation System (Vol. 1)(serving area)ccooling coilcooling loဝchilledpart-load operation“Dry Coil”Cooling c-(perform)sd“Wet Coil”cဝ၏၏ Dcondensation pcondensate watercooling coil“Wet Coil”၃-၃၄ Cooling and dehumidifying process of coilchilled water cooling coil၏ temperature gradient၃-၃၅ Chilled water cooling coil၃-၃၆ Direct expansion cooling coil(DX coil)Chilled water cooling coilchilled water(leaving temperature)ဝexpansion cooling coil (DX coil)refrigerantဝႈ(entering ��.၉ AHU Cooling Coil SpecificationCooling coilewww.acmv.orgair distribution system(air side)Airside loadchilled water system(water side)chilled water side3-20

Chapter-3 Air Handling Units(heat transferAHUAir c၏ဂ၊(manufacturer)(user)cooling coil specifica၏ technical r“York”cooling coilAltitude (ft)(sealevel)((select)ႈ(air density၊(air density)၏(air density)၏(၁(altitude)ႈ(sea level)Coil Type (BDW)(manufacture၏cwww.acmv.org3-21

Air Conditioning and Mechanical Ventilation System (Vol. 1)Tube / Fin Material (Cu/ Al)Coil ၏ ��“Alu”Tube Height / Fin Length (38/87)၏(heightf၏(length)Rows / FPI / Circuit (6/8/C)၏(Vertical)၏row(coppFins Per Inch(FPI)၏f၏ccoi ၏ffincoolingႈႈ(pressure drop)(air resistance)bCoil Area၏၏cheatingCoilCoilAir On DB/ WBcooling coil“၏”ဝ၏ဂဝဝ“”“၏cooling coil”(air properties)Dry BulbWet BulbFAir Off DB/ WBcooling coil၏“”cooling coilဝ“”“၏ဂBulb၏”(air properties)DryWet BulbFFace VelocityCooling c(air velocity)(air velocity)“WetCoil”ႈf2.5m/s(draincooling coilpan)“”www.acmv.orgf3-22

Chapter-3 Air Handling Units(heat transfercooling coil(air)Face v၂၅cooling coil၃(heat)(2.5m/s or 500 fpm)Heating c၏၄Air Pressure Dropcoolingcoil(pressure)”Prop”ႈ(air pressure dorp)ႈ(air pressure dorp)b၏(၈)(၁ )(energy)ႈ ႈSunction Temp for BDXRefrigeradirect expansion (DX)Water ON/OFF Temperaturecooling cဝchilled wchilled water supply te“”၏emperatFcooling coilchilled ww၏“chilledure immediately after the coil.”FWater Flow RateCooling cchilled waterႈ (flow ratetotal cooling cႈႈ(pressure drop across the coil)(total capacity)AHcoilႈ (flow ratechilled wChilled wechilledႈ (flow rate)ႈ (flow rate)w၏ coolingႈ(pumping energy)Water Pressure DropChilled water supply pressureChilled water supply pressure(pressurewww.acmv.orgchilled water return pressure၏chilled water return pressurechilled wcဝ3-23

Air Conditioning and Mechanical Ventilation System (Vol. 1)Chilled waterဝႈ (flow rate)coolingcႈ(water pressure drop)pressure drop)ႈ(water(pumping energy)၏(၈)(၁ .၁ဝ Sensible Capacity ၊ Latent CapacityTotal CapacityIPQS(Btu/hr) 1.1 x CFM x(t2-t1)QL(Btu/hr) 0.68 x CFM x(W2 – W1)QTotal(Btu/hr) 4.5 x CFM x(h2-h1)SIQS Sensible Capacity(Watt) 1.232 x L/s x(t2-t1)Q L Latent Capacity(Watt) 3012 x L/s x(W2 – W1)QT Total Capacity(Watt) 1.2 x L/s x(h2-h1)CFML/s Volume Flow Rate of Air being process.h2-h1 Enthalpy Change(Btu/lb F)(kJ/kg K)t2-t1 Temperature Change( )w2 – w1 Humidity Ration Change(lbw/lb d.a)( F(kg/kg d.a)Cooling Coil Sensible Heat Factor(SHF)FormulawhereSHF room sensible heat factorSensible Cooling CapacityTotal Cooling CapacityFSensible Heat Load (kW or Btu/hr)Total Heat Load (kW or Btu/hr)(၁ ဝ)F(၁ ဝLatent cooling capacityheat llatentc(dehumidification)www.acmv.org3-24

Chapter-3 Air Handling UnitsCoil LoadCoil loadcoilheat)sensible heat“““”latent heatCooling coilဝcooling coilOff coil temperature ၏total၏၏ႈ (air flow rate)Cooling coilchilled water12 Coff coil temperature12 Cႈ (air flow rate)11.5 C17 Cႈ (air flow rate)18 C DB(Pre cooled coil)Wet Bulb Depression“ulb Depression”(WBoff coil air temperature ၏ Dry Bulb(DB)Off coil airleaving air ၏ “BulbWet Bulb”0.12 C“”finဝ (fin spacing)Finဝ“spacing(fin”Over coolinglarge wet bulb dWet Bulb depression0.5 Ccoil၏1.0 CChilled Water VelocityCopper tubem/s)chilled water0.3 m/s(velocity)( .၃)ႈ (0.3turbulence flowcoil ၏ tubeCoolingcoil ၏performance)(heat transfer(၁.၅)1.5m/sႈ (1.5m/s)tubevelocity)coil ၏velocity)၏tube(water velocity)(waterႈ(water pressure drop)(waterႈFin Spacing“Fpacing”finဝspacingfin12 FPIfinCoil ၏၏Fin(face area)(length)Cooling coil ၏FPI၊ 12 FPIwww.acmv.orgtube ၏tube14 FPI(length)(၁၂)finned areaLH”၊coil ၏”coil(height)”8 FPI၊ 10fin spacing3-25

Air Conditioning and Mechanical Ventilation System (Vol. 1)Coil ၏(depth of the coil)rowRowcoil ၏Cooling coil ၏(performance)၊heat transfer coefficient(surface)၊ LogMean Temperature Difference (LMTD)ΔAtemperature difference between supply air and return aΔBtemperature difference between chilled water supply and rႈ(heat transfer)Log Mean Temperature Difference(LMTD)U-factorthermal transmittanceheat transfer coefficientcoil ၏ overall heat flow rateU factor(၁)Air side coefficientဝair streamheat transferfin(surface)(resistance to heat transfer)(barrier)(၂)Water film coefficientchilled watercopper tube(barrier)(၃)Thermal conductanceCoilaluminum filmcopper tubeႈ (air flow rate)resistance)ႈႈ (velocity)(heat transferwater sideႈ(heat transfer resistance)Fin႑ (geometry)overall heat transfer coefficientCoil ၏(face area)ႈ(heat transfer)၃.၁၁ Cooling Coil Header ConnectionAHUcooling coilpipe)ဝ(order)(header(Right Hand – RH coil connection)(Left Hand – LH coil connection)return a(RH)www.acmv.orgဝconnection(LH3-26

Chapter-3 Air Handling Units၃-၃၇ Righit Hand (RH) and Left Hand (LH) Coil Connection၃.၁၂ AHUpipe ၊ fitting၃-၃၈ AHUChilleddevicepipe ၊ fittingwatersupplysidedeviceChilled water returndevicedevice(A) Gate valve(Isolation valve)(A) Gate Valve(Isolation valve)(B) Pressure gauge(B) Pressure gauge(C) Thermometer(C) Thermometer(D) Strainer(E) Balancing valve(F) Motorize valveChilled water control valve၃.၁၂.၁ (A) Gate ValvesGate valve(isolation)AHU ၏ chilled water supplyreturn(devices)(devices)၏www.acmv.org3-27

Air Conditioning and Mechanical Ventilation System (Vol. 1)chilled water supply“Gate Valve”AHU ၏chilled water return“Gate Valve”fittingAHU ၏gate valveဝ၌fittingAHU ၏ supplyreturngate valve၃-၃၉Gate Valve၃.၁၂.၂ (B) Pressure GaugePressure gauge(chilled water supply)chilled water returnAHU ၏ cooling coil၃-၄ Pressure Gauagechilled waterဝ၊၃-၄၁ႈ (chilled water flow rate)Chilled waterpressureႈ (flow rate)chilled water supply pressure၏difference)(pressurechilled waterႈ (flow rate)AHU ၏ specificationpressure gaugeflow rate)gaugewww.acmv.orgchilled water returndifferential pressure across the coil ၏ႈႈ (Actual chilled waterႈSupply pressure(pressure၊3-28

Chapter-3 Air Handling Units၃.၁၂.၃ (C) Temperature GaugeThermometerTemperature gaugesupply(thermometer)chilled water returnsupply temperature(chilled water)Chilled waterchilled water return temperatureCooling coil ၏(performance)(Troubleshooting)၃.၁၂.၄ (D) StrainerStrainerAHU ၏ဝဝ (chilled water supply)chilled(filter)AHUwater၊ႈ၊ cooling coil ၏ႈstrainerstrainer(mesh)၃-၄၂ Strainer၃-၄၃ Balancing Valve၃.၁၂.၅ (E) Balancing ValveBalancing valvePump(design flow rateAHUrate)friction lossPumpwater flow rate) chilled water flow rateဝႈ (flowAHUpumpဝchilledAHUႈ (flowrate)၃-၄၄ Two way valve and Three way valve၃.၁၂.၆ (F) Chilled Water Control ValveAHU“Modulating Valve”www.acmv.orgModulating Valvechilled waterCooling load၃-၄၅ chilled water control valve and Actuatorႈ (flow rate)AHU ၏ cooling loadchilled water၍ႈ (flow rate)“Actuator”3-29

Air Conditioning and Mechanical Ventilation System (Vol. 1)၃.၁၃ AHUFCU DrainAHUcondensate waterdrain pandrainpipeDrain panAHUDrain pipeAHU(site)Air Handling UnitdrainpipetrapDrain(copper)PVC၃-၄၆ Trap for Draw-Through UnitTee joint၏၊(removable) plugဝRemovable plugႈTrapfan ၏(outlet pressure)(၃-၄၆)(၃-၄၇)၃-၄၇ Drain PipAHU/FCU(Capacity in kW)7 kW7.1 kW)35 kW25mm ( ၁35.1 kW106 kW32 mm ( ၁106.1 kW176 kW40 mm ( ၁ -၃/၄176.1 kW616 kW50 mm ( ၂)616.1 kW1050 kW75 mm ( ၃)Air Handling Unitwww.acmv.org(mm)19 mm (၃/၄၃.၁၄ Air Handling Unit ( AHU )(၁)Drain)))(Code)control device3-30

Chapter-3 Air Handling Units(၂)AHUcooling coilfinned coil(8 row8 rowrowcooling coilcooling coil(cleaning)(၃)၏) Air treatment processCooling coilservicingcondensate waterCondensate drain pan(drain) U bendfloor trap(Air breakbetween the condensate drain pope and the floor trop. )(၄)AHU(switched off)cooling coilcondensate waterAHU(၅)AHU ၏ fanblowercooling coilchilled waterဝ(၆)AHU ၏၊ �� �းထားျခင္း မျပဳရ။ Air consystemၥAHUsystem(installation)(၈)AHUCode of practice for Fire Precaution(operate)ဝ(firesafety requirement)၃.၁၄.၁ AHU Fan System Design CriteriaAHUblower ၏fan4 kWFan power limitation in air conditioning systemAllowable Nameplate motor powerConstant Volume (CAV AHU)Variable Volume1.7 kW / m³/s2.4 kW / m³/sVariable Air Volume System(VAV) AHU(fan nameplate motor2.4 kW/m³/sႈ2.4 kW)Constant Air Vloume System(CAV) AHUkW/ m³/skWfan motor ၏ Nameplate reading(ႈ1.71.7)Air conditioning system(automatically s() 7 day peration)3-31

Air Conditioning and Mechanical Ventilation System (Vol. 1)function( )Occupancy sensoroccupancy sensor(no occupant)(ဂ)(detect)Security systemAHU(၃ )(shutdown)security systemAHU(shutdown)(guest room)(manual on/off) AHUဝ(ဃ)ႈ (air flow rate) 5 m³/sAHUOptimum start control algorithm၏set point(differential temperature)( )၊(zone)optimum start control၏(room temperature)scheduled occupancy၏၏ AHU2300m²(zone)၊( )AHU(shutdown)(outdoor air intake)()AHUဝexhaust air system(shutdown)AHUoccupancybuilding“cool-”P -–-outdoor air damper( )A(space)outdoor supply airsystem( )exhaustdamperDamper(pressure)Pႈ(maximum leakage rate)damper ၏100 l/sdamperper m²ႈ (leak)100l/s 2.4 m³/s၊fan systemoutdoor air connection ႈ (designexhausted airဝairflow)၏၁ %exhaust air system(zone)ဝ (zone)F၏(power)automatic shutdownဝ0.5 kWဝPart load fan power limitation၏www.acmv.org(power)11 kW3-32

Chapter-3 Air Handling Units() VAV system AHU f၏(power)Variable speed drive (VSD/VFD)11 kW၊-variable pithblade( )ႈ (design airflow) ၏ ၅ %static pressure set point၏ demand1/3 ofdesign wattage၃ %Static pressure sensor locationVAV System AHUstatic pressure sensor1/3 oftotal design fan static pressureductဝmain branch ductductMainmajor brach ductstatic pressure sensorSet point resetDirect Digital Control(DDC)resetdamper၃.၁၅ VAV AHUBuildingVAV Boxset point95%static pressure set pointreset lower()၏ ControllerAutomationAHUControl LogicSystem၌AHU၏ Direct Digital Controller(DDC)graphicControl logicBuilding Automation System၃-၄၈ Building Automation System(BAS)www.acmv.orgAHU graphic3-33

Air Conditioning and Mechanical Ventilation System (Vol. 1)၃-၄၉Air Handling Unitfield device၊ InputOutputLegendSP: Static pressureST: On/Off statusRH: Relative HumidityTA: trip alarmWFR: water flow rateA/M: Auto/Manual modeKWH: kilo-watt hourSD: Smoke detectorS/S: Start/Stop controlDPS:DifferentialpressureVSD: variable speed driveswitchM: motorised actuatorWLD: Water leakage DetectorO/C: Open/Close controlT: Temperature၃-၄၉Air Handling Unitfield device၊ InputOutput၏ Legend၃.၁၅.၁ DescriptionVariable Air Volume (VAV) AHU control applicationController (DDC)Direct Digitalmodel UAH2484LDirect Digital Controller (DDC)၏ InputDirect Digital Controller(DDC) UAH24842LInput(1)Digital Input(Dry contacts)Direct Digital Controller(DDC) UAH24842Lwww.acmv.orgDigital Input (၁၅)(connect)3-34

Chapter-3 Air Handling Units၃-၅ VAV AHUVAV AHU၏ controller၏ controllerInputOutputcontrol logicDigital Input Selector mode status On/Off status Trip status Smoke detector status(maximum 4 nos.) General dry contacts(maximum 8 nos.)(2) Analog Input(0-5 Vdc/4-20mA/ NTC 10K temperature)Direct Digital Controller(DDC)UAH24842LAnalog Input (၁၂)(connect)Analog Input Temperature sensors(maximum 4 nos.) Static Pressure Chilled water flow rate CO2 Universal Input(maximum 5 nos.)Analog Input monitoring“Fwww.acmv.org(abnormal) sensor readingrder Low Pass Filter Method”3-35

Air Conditioning and Mechanical Ventilation System (Vol. 1)Where,Vnew New reading to be updated in DDCVold Old reading updated in DDCVin Sensor reading,C constant(0.0 1.0)(3) Pulse InputDirect Digital Controller(DDC) UAH24842Lpulse width(value) 0၅1,999,999,999pulse Input (၁)(50ms)(connect)Accumulated counter(display)OutputDirect Digital Controller (DDC) UAH24842LOutput(0-10 Vdc or 4- 20mA)Digital Output(24 Vac Triac) & AnalogC(4) Digital AHUDigitalDigital Output control (၁)outputchannel(၅)configure/AHU Start/Stop(Individual schedule or manual control)F/Fan 1 Start/Stop(Individual schedule manual control)(used as By pass damper control )F/Fan 2 Start/Stop(Individual schedule manual control)Return air damper/Return air damper Open/Close control(interlock with AHU operation)Exhaust air damper/Exhaust air damper Open/Close control(interlock with AHU operation)(5) Analog OutputDirect Digital Controller(DDC) UAH24842LAnalog output channel AHU Variable Speed Drive(VSD) control AHU chilled water valve control၃.၁၅.၂ DDC Terminal Block Assignment (UAH2484L)Terminal Block (၇)www.acmv.orgTB1TB6TB8 terminal3-36

Chapter-3 Air Handling UnitsTerminalBlock on 24V24 VAC Input(L)COM24 VAC Input(N)AO1Analog Output 1COMCom terminal for AO1 & AO2AO2Analog Output 2UI1 – UI4Universal Input 1-4COM2 COM Terminals for UI 1-4UI5 – UI8Universal Input 5-8COM2 COM Terminals for UI 5-8UI9 – UI12Universal Input 9-12COM2 COM Terminals for UI 9-12RemarkEach com shared by 2 UIEach com shared by 2 UIEach com shared by 2 UIUI13 – UI16 Universal Input 13-16COM2 COM Terminals for UI 13-16Each com shared by 2 UIUI17 – UI20 Universal Input 17-20COM2 COM Terminals for UI 17-20Each com shared by 2 UIUI21 – UI24 Universal Input 21-24COM2 COM Terminals for UI 21-24P3Pulse InputCOMCom terminal for P3 & P4P4Pulse InputTO1-TO8Digital Output 1 - 8N Network wire from previous DDCN-Network wire from previous DDCN Network wire to next DDCN-Network wire to next DDCEach com shared by 2 UIOnly P3 is used.OnlyTO1,3,5,6areused.TO3 not used for Tower 1၃.၁၅.၅ AHU Control LogicAHUoperating mode (၅)(၁) Purge mode(၂) Alarm mode(၃) Normal operation mode(၄) Manual control mode(၅) Bypass damper controlwww.acmv.org3-37

Air Conditioning and Mechanical Ventilation System (Vol. 1)၃ ၁၅ ၃ Variable Air Volume (VAV) AHU ၏ DDC LayoutWiring Diagram၃-၅၁ Variable Air Volume (VAV) AHU ၏ DDC LayoutWiring Diagram၃ ၁၅ ၄ Variable Air Volume (VAV) AHU ၏ Typical Sensor Termination(၁) Purge modePurge modeAHU“Flushing ode”“Foutput) controlled device On/Off(type) exhaust air damper(set to open) On/Off(type) return air damper(set to close) AHU supply air fanwww.acmv.orgenableode”((run)purge modeFan speed“Pode”set point3-38

Chapter-3 Air Handling Units Modulating(type) chilled water valve(set to 0%)၃-၅၂ Variable Air Volume(VAV)AHU ၏ Typical Sensor Termination(၂) Alarm mode“ode”AHUAHUBlower ၏ VSD speed0% (set to 0%Return air damper(set to close)AHUdamperchilled water valve(open)Exhaust air damper(fully close)return air(close)(၃) Normal operation �www.acmv.org၊mode selection switchAuto modeselector switchMode selection switch3-39

Air Conditioning and Mechanical Ventilation System (Vol. 1)selector switchlocal modeDDC၊(၄) Manual control Mode On/Off(type) exhaust air damper On/Off(type) return air damper AHU supply air fan(set to close)(set to open)fan speedPID algorithmstatic pressure setpointoutput contol singal Modulating(type) chilled water valvealgorithmVSDcooling set pointoutput contol singalPIDmodulating actuatorAHU On/Off type Exhaust air damper(set to close) On/Off type return air damper VSD output(set to open)0% Valve output(set to 0 %)0%(set to 0 %)(၅) Bypass damper controlBypass damper control၊AHU(open/close)interlockmanuallyChilled water valve controlPActuatormodulating type chilled water valvecontrol0 10 Vdc control signalTemperature setpointdefault PID parameter default setpoint Supply air temperaturecontrol PID loop Proportional band ၏ default value Dead band ၏ default valuewww.acmv.org43-40

Chapter-3 Air Handling Units၃-၅၃ Modulating valve control၃-၅၄ Temperature controlIntegral ၏ default value(derivative constant default valuePI control)Supply Fan Variable Speed Drive (VSD) controlPFSignalVariable Speed Drive(VSD)controlOutput0 10 VdcTemperature setpointdefault PID parameter Default setpointP Minimum supply air static pressureSensor rangecontrol PID loopP Proportional band ၏ default value Dead band ၏ default valuePPIntegral ၏ default value(PI controlderivative constant default value)၃-၅၅ VSD control၃-၅၆ Static Pressure Control-End-www.acmv.org3-41

_ ၃.၅၁Direct expansion coil(DX Coil) 3-12 _ ၃.၅၂Chilled Water Cooling Coil 3-13 _ ၃.၅၃Hot Water Heating Coil 3-14 _ ၃ .၅၄Steam Heating Coil 3-14 ၃.၆ Coil (Size) 3-15 ၃.၇ AHU Cooling Coil 3-16 _ ၃ .၇၁Coil ၏Row Fin 3-17 ၃.၈ Dry Coil Wet Coil 3-20