Karvidės vėdinimo sistemos reguliavimo metodo sudarymas

Abstract

Taikant statybinės šiluminės fizikos ir aerodinamikos principus bei atlikus tipiškų karvidžių statybinių ir technologinių rodiklių analizę sudarytas naujas natūralaus vėdinimo sistemos parametrų apskaičiavimo ir reguliavimo metodas, pagal kurį užterštam orui šalinti kraigo plyšio plotas atitinka šalčiausio laikotarpio (šalčiausio penkiadienio) reikalingą vėdinimo intensyvumą ir nereguliuojamas, o šviežiam orui įeiti angų sienose plotas keičiamas priklausomai nuo lauko oro temperatūros pagal sudarytą formulę. Tipiškoms pastaraisiais metais statomoms karvidėms rekomenduotinas užterštam orui šalinti kraigo plyšio savitasis plotas (plotas gyvulio bendrosios šilumos srauto kilovatui arba 500 kg masės karvei, duodančiai 18 kg pieno per parą) – 0,05-0,07 m². Didžiausias šviežiam orui įeiti angų vienoje išilginių sienų savitasis plotas – apie 0,12 m²/kW. Krentant lauko oro temperatūrai nuo 25 °C šilumos iki 20°C šalčio šis plotas sumažinamas 80 %

The objective of the work is to compose the new regulation and calculation method for natural ventilation system parameters, according which, in order to eliminate polluted air, the opening of cowshed ridge would satisfy the required ventilation intensity during the coldest period without being regulated. The width of openings in the wall for fresh air is changed according outside temperature, subject to the equation. While composing the method, analytical researches were used, applying construction thermal physics and aerodynamic principles. The ultimate equations were related to the construction and technological factors of recently built and perspective cowsheds. In order to increase the universality of the method the width of the ventilation openings are expressed in total animal heat flow unit. The equation for calculation of specific width of ridge openings for elimination of polluted air was composed; as well as the equation for calculation of specific width of wall openings for fresh air. For practical application of this method the data was collected about constructions and technological rates of 21-24 m width cowsheds in 160-230 places. As a result the equation was composed, according to which the width of the openings for fresh air was regulated. The recommended specific width of ridge openings for elimination of polluted air (the width per one total animal heat flow kilowatt) is 0.05-0.07 m²/kW. The greatest specific width of openings in the one longitudinal wall for fresh air is 0.12 m²/kW. When outside temperature decreases from plus 25 °C to minus 20 °C this width is reduced to 80 %