夏季通风系统

TUNNELVENTILATION

纵向通风

September2011BernardGreenDISCUSSIONTOPICS

议题ClosedEnvironmentHouses

密闭环境式鸡舍WindChill

风冷效应TunnelVentilationDesign

纵向通风系统设计CoolingSystems

冷却系统RelativeHumidity

相对湿度EvaporativeCooling

蒸发冷却OperatingaCoolingSystem

操作冷却系统OperatingTunnelVentilatedHouses

操作纵向通风鸡舍HotWeatherPreparation

炎热季节前的准备工作CLOSEDENVIRONMENTHOUSES

密闭式鸡舍CommonlyknownasTunnelVentilation(TV)

通常知为纵向通风For(effective)temperaturecontrolinhotweather

夏季有效控制温度Takesplacedownlengthofhouse

整个鸡舍内都在运作Exhaustfansatonegableend

排风机安置在鸡舍末端边墙上Longinletsineachsidewallatoppositeend

另一端两侧有长的进风口Airispulleddownlengthofhouse

空气从一端拉到另一端Coolingeffectofairmovement(windchill)

空气运动的冷却效果（风冷）Fansvaryairspeedandeffect

风机效能决定风速和效果TunnelVentilation

纵向通风WINDCHILL

风冷效应ProbablythemostimportantfactorinTV

纵向通风中最重要的因素Coolingeffectfromairmovementonthebirds

空气运动对鸡只的冷却效果Dependson:birdage,drybulbtemperature,airspeed,RH

取决于：鸡只日龄，干球温度，空气速度，相对湿度Remember-Controllerprobe,drybulbthermometercannotmeasurewindchill

记住

–控制器的探针，干球温度计无法测量风冷效应Variouswindchillchartsavailable

可得到不同风冷效应的图表HowmanyfansshouldIuse?

我应该使用多少台风机呢？Always

basethefinaldecisiononbirdcomfort

鸡只舒适决定一切WindchillExample

风冷例证0.51.01.52.02.53.0AirVelocity(m/s)8.05.53.51.09.06.54.52.0WindChill(°C)OlderBirdsYoungerBirds-ExampleTUNNELVENTILATIONDESIGN

纵向通风设计Twofactorstoconsider:

要考虑两个因素：1. Airspeed

空气速度fancap.[m³/hr]=speed[m/s]xCSA[m2]x3600

风机排风量（立方米/小时）=速度（米/秒）xCSA(平方米)x3600CSA=crosssectionarea

CSA=横截面积CSA=(WxH)+(½WxR)

CSA=

（宽X高）+（1/2宽XR）3600=convertm/stom/hr

3600=米/秒变成米/小时NarrowhousepreferredforTV

狭窄的鸡舍最适合用纵向通风系统Selectfanbasedon

operatingpressure

根据工作压力选择风机FanOperatingPressure

风机的工作压力∆P∆P∆P∆PFanOperatingPressure=∆P+∆P+∆P+∆P风机工作压力∆P∆PFanPerformanceExample

风机性能12mHouse–8x50”fans40500m³/hr→2,65m/s38000m³/hr→2,54m/s34500m³/hr→2,30m/s32000m³/hr→2,10m/sFanPerformanceExample

风机性能例证PressurePa01225313750FanCapm³/hr431854063538084363843468430434PressureInWC0.000.050.100.120.150.22. Temperaturegradientfrominlettofans

进风口到出风口的温度梯度Veryimportantinlong,widehouses

对长而宽的鸡舍尤为重要Considerbirdgeneratedheat

要考虑鸡只也产生热Radiantheatgainfromsun(throughroof)

来自太阳（穿过屋顶）辐射热的增加Keeptemperaturerise<2,5°C

保持温度上升小于2.5摄氏度.Totalinletareamustmatchfullfanoperatingcapacity

整个进风口面积必须与所有风机的排放量相匹配.AirDeflector风挡AirDeflectors

风挡Usedinhouseswithlowairspeedorhighroof

用于风速低或高屋顶鸡舍AirDeflectorshave2effects:

风挡具有两个效用:1. IncreaseairspeedbyreducingCSA

通过降低截面积提高风速2. Makesairmovementmoreuniform

使空气运动更加均匀Evensoutairspeedfromsidewalltosidewall

均衡鸡舍内一侧边墙至另一侧边墙的风速AirDeflectors

风挡Installation

安装Installnomorethan10mapart

安装间距不要超过10米Donotinstalltoolow!

不要安装的过低!Minimumheight±2,4m

最低高度约2.4米Toolowcanincreasepressureonfansandhaveoppositeeffect

安装过低会对风机增大压力,会产生相反效果.

COOLINGSYSTEMS

冷却系统Atsomestagewindchillisn’tenough

某些阶段风冷效应并不够Airmustthenbecooled

所以空气必须要进行冷却Options:

选择:1. Spray(foggers)

喷雾2. CoolingPads

湿帘CoolingPads

湿帘Calculatingpadarea:

计算湿帘面积MustknowtotaloperatingTVfancapacity

必须知道纵向通风鸡舍总的风机排风能力padarea[m²]=fancap[m³/hr]÷2,03[m/s]÷3600

湿帘面积(平方米)=风机排风量(立方米/小时)÷2.3(米/秒)÷36002,03m/s

designairspeedthru150mmpad

通过150毫米厚湿帘风速1,27m/s

designairspeedthru100mmpad

通过100毫米厚湿帘风速3600

conversionfromm³/hrtom³/s

小时立方米转成秒立方米Installequallyoneitherside(atendofthehouse)

对等安装一端两侧Ensurepadisinstalledincorrectorientation

确保湿帘按正确方位安装Preferabletoinstalloncoolingpadroom

最好安装湿帘间Allowspressurecontrolafterpad

空气通过湿帘后压力可控制Easiertosealinwinter(veryimportant!)

冬季便于密封（特别重要）66%74%24CoolingPadOrientation

湿帘方位CoolingPadRoom

湿帘间（湿帘小屋）CoolingPad湿帘(150mm)WeightedCurtain自重卷帘RackandPinionInlet带框架挡板的进风口RELATIVEHUMIDITY

相对湿度Comparisonofamountofwaterintheairatacertaintemperature,relativetomaximumpotentialamountatsametemperature

Coldair

canholdlittlemoisture

冷空气=含水分较少Hotair

canholdmoremoisture

热空气=含水分较多Astemperatureincreases,RHdecreases

随着温度上升，相对湿度降低Astemperaturedecreases,RHincreases

同上相反TemperatureRHEVAPORATIVECOOLING

蒸发冷却Whatisit??Howdoesitwork??

这是什么？怎么工作的？Nothingtodowithwarmairagainstcoldwater

与暖空气与冷水作用无关Nothingtodowithcoldwateronthebirds

与冷水和鸡只无关Little(nothing)todowithwatertemperature

与水温几乎没关系Achievedbyatransferofenergy(heat)fromthehotairtothewater

将热空气中的热能转换成水Airgivesenergytowater

coolerair

空气将能量给予水分

较凉的空气Waterabsorbsenergy

evaporates

水分吸收能量

蒸发Amountofcoolingpossibledependsonoutsidewetbulbtemp(RH)

冷却的量取决于外界的湿球温度（相对湿度）Dryenvironment(lowRH)

veryeffective

干燥的环境（较低的相对湿度）

效果非常好CoolingPotential

冷却潜能ΔT=MaximumcoolingpossibleCoolingpadis±75%efficient,soActualcooling=0,75xΔTThiswillbethetemperaturerightatthepadDryBulbWetBulbΔTΔTΔTsmallHighRH(humid)SmallcoolingpotentialHumidclimateEarlymorningLateafternoon,eveningΔTbigLowRH(dry)BiggercoolingpotentialDryclimateDuringpeaktemperatureBirdsandEvaporativeCooling

鸡只与蒸发冷却Whenabirdisheatstressed,itlosesheatintwo

鸡受热应激时，两种释热：ways:1. Convection,conduction,radiation(airmovement)

对流，传播，散发 Occursduringinitialstagesofheatstress

热应激最初阶段发生2. Evaporativecooling

蒸发冷却Whenairmovementisnolongeradequate

空气运动不再起作用时Evaporativecoolingtakesplaceinthebird

鸡只开始蒸发冷却Asthebirdbreathes,airpassesoverthewetsurfacesofitsrespiratorysystem

随着鸡只呼吸，空气经过其呼吸系统潮湿的表面Likeacoolingpad,moistureisevaporated

就像湿帘，水分被蒸发Effectisincreasedbypanting(upto250/min.)

急速喘气增加效果250/分LowRHeasiertoloseheat

相对湿度低

较容易释放热能OPERATINGACOOLINGSYSTEM

操作冷却系统EffectivenessofbirdscoolingsystemdependsonRHofairaroundit

冷却系统的效果取决于周边空气中的相对湿度IfRHlow

effective

如果相对湿度低

有效果IfRHhigh

ineffective(canleadtomortality)

如果相对湿度高

无效果（可导致鸡只死亡）RuleofThumb(guideline):

法则（指导）IfhouseRH>70%,switchcoolingOFF

如果鸡舍RH>

70%，关掉湿帘Temperaturewillincrease,RHwilldecrease

温度上升，RH下降CANNOT

operatecoolingontemperaturealone!MUST

operateoncombinationofTempandRH不能只是根据温度来操作湿帘必须综合考虑温度和相对湿度OPERATINGTVHOUSES

管理纵向通风系统的鸡舍Usefanstoregulateairspeed,windchill,birdcomfort

利用风机调节风速，风冷效应和鸡只舒适程度Ifthebirdsareallsittingflat,theremaybetoomuchairmovement

如果鸡只全部卧在地上，有可能是风速太大。Beextremelycarefulwithyoungchicks

对于年轻鸡只要格外小心Tunnelinletmustbepressurecontrolled

纵向通风的进风口必须靠压力控制NEVER

operatefansonlyondrybulbtemperature

切勿只靠干球温度操作风机Thermometers,sensorscan’tfeelwindchill

温度计和感应器无法感觉到风冷效应Watchbirdcomfort(don’tventilateforhumancomfort)观察鸡只舒适（通风不是为了人员的舒适）Thebirdswilltellyouiftheyarehot,cold,comfortable

鸡只会告诉你是否冷热，是否舒适。Whenallfansareon,onlythenintroducecooling

所有风机运转之后再开启湿帘HouseRH>70%

switchcoolingOFF

RH大于70%，关闭湿帘。IfRHdropsbelow70%,canswitchbackON

如RH低于70%，再重新开启湿帘Moderncontrolsdothisautomatically

现代控制系统都是自动控制。OPERATINGTVHOUSES

管理纵向通风鸡舍ThepurposeofacoolingsystemisNOTtoreducetemperaturetothesetpoint

冷却系统的目的不是把温度降到设定点。ItistoHOLDthetemperaturewherethebirdswerelastcomfortable

只是把温度控制在以往鸡只感到舒适的范围。WhenRHishigh,airvolume/exchangeiscritical

相对湿度高时，空气量/交换量十分重要。Movegentlythroughthehouseandgetbirdstostand,releasingheatload

空气较温和地通过鸡舍，使鸡只站立起来，释放积蓄的热能。ReleaseentireheatloadbeforeswitchingtoCrossVentilation(minimumventilation)

启动横向通风系统（最小通风系统）之前，要排除全部积蓄的热能。PoorlyDesignedTunnelVentilationSystem

设计差的纵向通风系统NoAirMovement0,4m/s0,8m/s1,3m/sAirExchangeRate=1,5minutes空气交换率=1.5分钟Canexpectheatst