Wide Body Freestall Buildings Understanding the System

Transcription

1 Wide Body Freestall Buildings Understanding the System Joe Harner K-State Dairy Team Kansas State University Manhattan, KS /

2 Lower profile roofs results in a higher proportion of the air space being at the cow level potentially more airflow 2

3 300 to 350' for conventional natural ventilated freestalls Natural ventilated freestalls - 4/12 roof slope 4-Row Conventional Freestall Building Cross ventilated freestalls - 0.5/12 roof slope 30'-8" 17'-1" 100 to 150' between buildings 220' for low profile cross ventilated freestalls 100' 8-Row Low Profile Cross Ventilated Freestall Building Fans Airflow Cow Feed Baffle (Bottom 8 ft above alley) Airflow Feed Drive Feed Structural support posts of roof not shown Roof Slope - 0.5/12 Cow 210' Cow Feed Feed Drive 10' Evaporative Pad Airflow 18' Airflow Airflow Feed Cow 13' Low Profile Cross Ventilation 3

4 First LPCV constructed in ND 64 m x 128 m ft & 800 Crossbred cows Roof slope -.5 in 12 4

5 Dairy Footprint 8,400 Cows 55 Hectares 5

6 5,000 cows 130 m x 410 m 1,200 cows Low Profile Cross Ventilation 6

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8 Critical Areas for Airflow Cross -Section Area sq.ft. Cross-Section Area = 37 sq m 12 sq m 6 sq m 128 sq ft 64 sq ft FEED LINE AREA 5 hrs/day FREESTALL AREA hrs/day 8

9 To Milk Parlor Evaporative Pad 200 Cows Bottom of Baffle 8' above alley floor (6'4" opening) 200 Cows 210' Entrance Doors 200 Cows Baffle 200 Cows 200 Feedspaces 20' Cross (2-8' Water Troughs) 184 Freestalls per Pen (46" stall width) NORTH 84-51" fans located along west side 420' Cross -Section Area sq.ft. 128 sq ft 64 sq ft 9

10 Impact of Roof Slope 30 m wide & 4 m Sidewalls Roof Housing Roof Slope Roof Area Housing Area Total Area Roof / Total % ½ / m 2 121m m % 1 / m 2 121m m % 2 /12 39 m 2 121m m % 3 /12 58 m 2 121m m % 4 /12 77 m 2 121m m % 10

11 Building: Width 60, 75,90, 120 & 150 m Wide Ventilation controlled by sidewall inlet Wider building Increased air exchange Increased temperature rise Increased roof loads 11

12 Total Building Air Exchange Time Vs Width 3 m Pad/m of Building Length 4.3 m sidewall 0.5/12 roof slope Pad Velocity (mps) Nominal Building Width (m) sec 123 sec 174 sec sec 103 sec 145 sec sec 88 sec 125 sec sec 77 sec 109 sec 12

13 Evaporative Cooling 13

14 Ventilation: Open vs Pad vs Mist Add water cool air Evaporative Pad 75 % moisture High Pressure Mist Wet Bulb C High humidity low pressure soaker at feed line 14

15 Evaporative Cooling Evaporative Pads Recycles water Air uniformly cooled Winter insulation Controlled light High Pressure Mist Increase contact time No water recycling Easier to install Curtain inlet Set contact time Water recycle system Life of pad Non uniform cooling Nozzle maintenance Water filtration system 15

16 Air inlet with an evaporative pad Two 1.5 m evaporative pads 3 m wide x 110 m long Winter inlet parlor transfer lane 16

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18 Cooling Efficiency (%) 10 vs 15 cm Pad Efficiency cm pad 15 cm pad Face Velocity (m/s) 18

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20 Impact of Evaporative Cooling on Barn #2 Temperatures Ambient Ave 23.8 C ( ) Lower Temperature Limit (C) Ambient Pen 1 9 m from pad Pen 6 82 m from pad > hrs 161 hrs 254 hrs > hrs 40 hrs 96 hrs > hrs 0 11 hrs Time Period July 17 to August 16 ~ 720 hours of continuous data collection 20

21 Comparison of LPCV Dairies Dairy Average Temperature Rise Between Baffles or Pens Temperature Rise/Foot of Building Width LPCV # o C 0.47 o C/30 m LPCV # o C 0.43 o C/30 m LPCV # o C 0.61 o C/30 m LPCV # o C 0.53 o C/30 m LPCV #5 Not available 0.32 o C/30 m Average 0.32 o C 0.47 o C/30 m 21

22 Relative Humidity (%) Comparison Relative Humidity When Ambient RH is > or < 70 % RH > 70 RH < External Pen(Lote) 2 Pen(Lote) 4 Pen(Lote) 6

23 Comparison of Temperatures when Ambient RH is < or > 70 % Oct 31 to Nov 5, 2013

24 Comparison of THI when Ambient RH is < or > 70 % Oct 31 to Nov 5, 2013

25 Impact of Cooling System When RH is < 70 % or > 70 % on the Total Hours when THI is > 70 Oct 31 to Nov 5, 2013

26 Summer Environment - Brazil

27 Temperature Difference vs Outdoor Temperature Jan 1 to Mar 20, 2013

28 KSU Study on Evaporative Pads Pad efficiency is a function of exposure time & air moisture capacity THI > 25.5 C / % Tends to decrease the greater the moisture holding capacity of the air Air at given velocity & exposure time to moisture can only absorb so much Design 0.25 to 0.35 L/min/m 2 of pad area 28

29 Building: Insulation 3 Types Flexible fiberglass Close-cell, rigid & semi-flexible open cell Rigid board insulation Insulation vs no insulation Summer radiant heat Winter - condensation 29

30 Moisture condensing between insulation and roof Roof insulated but not purlins Moisture condensing on purlins no insulation on roof or purlins Roof and purlins insulated with spray on insulation 30

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32 Ventilation: Fans 1.5 kw / m fan most common Automated fan control Air Exchanges Summer -- 1 to 2 minutes Winter maybe 8 to 40 minutes Air exchange determined by inlet area 32

33 Fan horsepower is about the same as in a natural ventilated freestall with a row of fans over the feed line and freestalls the electrical energy differences is in ventilation during the spring, fall & winter however not all of the fans are operating during non heat stress periods. 33

34 Airflow Rate (m 3 /s) y = x x R² = Static Pressure (mm of water) 34

35 Ventilation: Baffles Baffles vs No Baffles Air speed in stall area (2.7 vs 1.3 mps) Soft vs Hard Baffles Curtains or metal One dairy felt baffles added 2.2 kg/cow/dy (no data to support from authors) 35

36 Baffle Opening Unobstructed opening Baffles Design Front of stalls (head to head) White metal - reflectivity Parallel to the feed lines 2.5 m above alley & 2 m above beds (61 m) WARNING : BAFFLE OPENING FUNCTION OF # OF BAFFLES & FANS 36

37 Air Velocity at High Ventilation Rate Velocity at Baffle 3 m/s Velocity at Inlet 1.78 m/s F A N S Cow Feed Feed Drive Feed Cow Cow Airflow Feed Feed Drive Feed Cow P A D S Velocity at Feed Rail 0.91 m/s Air Exchange Rate for the Building 64 Seconds 37

38 Static Pressure (mm of water) Baffles =.1 (.635 per Baffle) Pad = 1.27 F A N S Cow Feed Feed Drive Feed Cow Fans = 3.8 (Baffles + Pads) Cow Airflow Feed Feed Drive Feed Cow Static pressure drop per baffle may be estimated using Pitot tube equation P A D S 38

39 Baffle Opening (m) Influence of Air Speed and Number of Baffles on Baffle Opening Number of Baffles Air Speed Through Evaporative Pad (m/s) Note: Total static pressure limited to 4 mm and evaporative pad height equals 3 m. Baffle opening assumed to be equal to the top of the concrete curb and bottom of baffle. 39

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41 Fans Stall Cow Stall Feed Headlock Headlock Feed Stall Cow Stall Stall Cow Stall Feed Headlock Headlock Feed Stall Cow Stall Pads Light Level (footcandles) Building Light 25 footcandles Direction of Air Movement RECOMMENDED LIGHT RANGE Research 15 to 20 fc recommended 41

42 10 vs 2 vs 1 Doors 10 Doors - ~ 1 m at end 2 Doors - ~ 10 m at end 1 Door - ~ 15 m at end 42

43 5 Doors / m ft Great Door Debate 20' 80' R30' 1 Door / m ft R18' 12' 32' 10 m ' m w/out Doors 20' 80' R50' R30' 52' 16 m 20' 80' 43

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46 LPCV (wide body) Summary Thermal neutral environment maintained Baffles move air into stall space Floor space / stall is not size neutral Perimeter space of fan / inlet maintenance Dependent on number of end wall doors Power requirements Parlor the same Ventilation slightly increases (similar in summer) Artificial lighting requires more than natural long day Cold weather employee / cow advantages Land foot print reduced

47 Thanks -- Questions 47