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Originally, tunnel doors were only thought of as a method of reducing heating costs and litter caking in the tunnel inlet area of totally-enclosed houses.
Poultry farmers realized that:
The heaters near the tunnel curtains running nearly constantly during cold weather, while the remaining heaters operated only occasionally.
Poultry farmers who installed gates at tunnel entrances, with greater thermal insulation and tightness, often saw significant reductions in heating costs , which is not surprising considering the tunnel inlet can extend over 1/3 of the of the length of the brooding area in many of today’s broiler houses ( Figure 1 ).
Something that many producers discovered which they didn’t expect was that tunnel doors often proved nearly as beneficial during hot weather as they did during cold weather.
Producers found that tunnel doors produced better air movement in the tunnel inlet area, eliminated the “dead spot” near the side wall just past the end of the tunnel opening.
Most importantly, they improved side wall-to-wall air velocity uniformity throughout a house, all of which helped to lessen heat-stress-related production problems often experienced during hot weather.
Houses with traditional tunnel curtains
Incoming air doesn’t tend to stir much as it enters and moves down the house. It comes straight into the center of the house, collides with the air entering through the opposing tunnel curtain opening, and moves down the house toward the tunnel fans without a significant level of circulation.
Houses with tunnel doors
The incoming air pattern is very different, resembling the air circulation pattern created by the side wall inlets during cold weather.
The angled opening of the tunnel door directs the incoming air up to and along the ceiling, where it remains until it reaches the center of the house where it collides with the incoming air from the opposite side of the house.
It then rolls down toward the floor and then back to the side wall, creating a circular air flow pattern (Figure 2).
This circular air flow pattern continues for about 30 meters as the air moves down the house towards the tunnel fans.
It is this circular air flow pattern that increases the amount of air movement across the floor in the tunnel inlet area, eliminates the dead spot just past the end of the tunnel inlet opening, and promotes more uniform wall-to-wall air speeds throughout a house.
The benefits of circular air co...
