Intake device of natural ventilation system of livestock premises in windy weather and cold season

Abstract

The supply of external air to the livestock building in windy weather and in cold season is one of the problems of the natural ventilation system. In windy weather there is overcooling of the lower zone due to air pressurization from the windward side into the room through the supply devices, and in the cold season at low external temperatures a significant temperature drop occurs in the height of the livestock room. This problem can be solved by using a supply device, the intake pipe of which is equipped with a control valve to prevent overcooling of the lower zone of the room in windy weather, and in order to prevent a significant temperature difference in the cold season, the duct is elongated and installed parallel to the pitched roof of the livestock building. The control valve consists of two flaps pivotally mounted on the fixed shaft of the air intake pipe. The valves of the control valve are connected by a calibrated tension spring and are directed to the inlet of the air intake pipe with the possibility of their opening from the maximum approach to the maximum diluted position. This article presents the scheme and principle of operation, the results of theoretical research on the study of the intake device of the natural ventilation system of the livestock premise. The heat and mass change in the proposed air intake device is considered, the dependence of the degree of external air heating in the air intake device Δt н depending on the external air speed v and the air supply duct length x is obtained, and dependency graphs are constructed. It is confirmed that Δt н heating degree of the livestock premise decreases with the increase of the external air speed v and with the increase of x duct length it increases. It is noted that if the length x of the supply air duct is equal to 3 meters, the Δt н heating degree of the livestock premise is 5.6 ºC at -20 ºC external temperature.