Calculation the paremetrs of natural ventilation system of animal shed = Obliczanie parametrow systemu naturalnej wentylacji w pomieszceniach dla zwierząt

Abstract

In design a natural ventilation system for animal shed it is necessary to assess the ventilation induced by thermal buoyancy and wind forces during different seassons and under different animal housing conditions. The ratio of thermal buoyance and wind was established and the methodology was prepared to forecast ventilation intensity based on the calculations of air speed in inlet and outlet openings. The equation was formed to calculate the ratio of size inlet and outlet areas. The accuracy of the methodology was approved by experimental research under natural conditions of barn operation. The difference between the experimental and calculated air speed values in the ouitlet opening was insignificant and was within 0-8% range. According to the analytical and experimental research results it was calculated that in a typical animal house air speed in the outlet of the rooftop was 1.3 m/s (when there is no wind, this speed decreases to 0.3 m/s), ratio ventilation rate of thermal buoyancy and wind forces–0.27; and in order to have all air removed through the rooftop outlet in winter, the area of inlets in the walls does not have exceed 40% of the rooftop outlet area.