The Swedish pig house is generally closed. Fresh air enters the roof of the pig house first, and then walks through the ceiling air intake to the pig house.
The movement of the air is determined by the temperature difference inside the pig house. The pigs generate a lot of heat and cause the air flow to rise. The pigs, ceilings, walls and floors usually consume energy. When the weather is cold, an upward flow of air is formed in the middle of the pig house. At the ceiling, the air travels along the wall panels, floors, and then back to the center of the pig house, which is usually a pig's habitat. The temperature dropped along the way, and to the floor, the temperature dropped enough to create a steady flow of air.
The air inlet should move and cooperate with the airflow in the house. In Sweden, most of the air intakes are not on the wall but on the ceiling. In order to equalize the temperature as quickly as possible and avoid blowing the air directly onto the pigs, people try to mix the incoming fresh air with the air inside. This means that the air intake should be located in the middle of the pig house, and do not let cold air blow directly onto the pig.
The interior of the pig house is also part of the ventilation system. Most pigs in Sweden are kept on the floor and the floor is well ventilated. Now keepers realize that in order to prevent the air flow directly onto the pigs, there must be obstacles on the floor, and the wall and high troughs are used for this purpose. They also recognize that scorpions protruding from the walls and ceiling may interfere with the movement of the airstream, and due to certain structural obstacles, the incoming airstream may be deflected, creating a detrimental direct airflow to the herd .
Ventilation must not be affected by natural wind. If the air inlet and fan are mounted on the wall, the amount of ventilation can be determined by the wind passing through the pig house. So in Sweden, the air intakes are set on the ceiling and the fans are placed in vertical pipes. As a result fresh air must pass through the ceiling of the pig house. Due to the radiant heat ventilation brought about in the summer, many problems will arise. In order to deal with the problem of radiant heat, reflective roof panels are usually used. However, the most critical is the structure of the roof, which should allow air to enter the ceiling from the entire pig house.
The air must come in slowly along a wide enough slit so that the cold air layer enters the air inlet at a low velocity, while the hot air layer enters the upper part of the roof along the roof.
So modern Swedish ventilation generally has a good, controlled air intake; fans combined with shutters; heaters that heat the inside air and controls that control the air intakes, fans, shutters, and heaters. All of the above factors directly affect the temperature and humidity in the house.