Holding Area Barn A

DESCRIPTION

• Positive pressure tubes installed to supplement natural ventilation in the milking center holding area and aid in heat abatement.
• Airjets are targeted to reach 300-400 ft/min (1.5-2 m/sec) at the level of the cows’ backs, in effect “showering” cows with fresh air at minimum heat abatement speed when combined with soaking from sprinklers.
• All combined, the 6 positive pressure tube systems deliver fresh air at a rate of approximately 50 air changes an hour.
• Original design called for 6 tubes, but only 5 were put up. After one summer season, the producer has decided to add the additional tube to improve coverage over the entire holding area.
• The tube system uses less energy than the three rows of seven 36 in (91 cm) recirculating fans needed to sufficiently cool the holding area.
• Sprinklers were updated to improved coverage of the holding area and droplet size, and also located between the tubes. Soaking must be combined with fast moving air to provide heat abatement.
• Tubes are spaced every 9 ft (2.7 m) on center. The diameter of the tubes and number of holes are sized to match the fan air output, balancing static pressure, aperture ratio and discharge coefficient for consistent discharge along the length of the tube. Tubes are suspended with double-cable supports to prevent twisting and wear on the fan-tube connection, and to keep the bottom of the tubes clear of the crowd gate when they are not in use.
• The wall area between and below the fans is enclosed during operation to avoid drawing air from inside the barn and recycling it back through the tubes. The curtain below the fans may be opened during mild but not yet hot spring and fall weather while the positive pressure tubes are not running.

More information about holding area heat abatement strategies can be found on the Heat Abatement Blueprint page.