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Melžyklos temperatūrinio režimo panašumo modelio sudarymas
Date Issued |
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2005 |
The objective of this study is to develop a simulation model of temperature regime of typical milking parlor. The fundamentals of construction termophysics were applied while developing simulation model. The parameters of named model were expressed by total heat flow of animals, choosing milking place to be adequate to 1 kW of total heat of animals. Model developed initially had differential equation form. When the latter is integrated, the model is received, according which calculation is simple. The model evaluates the heat accumulation of external barrier and heat accumulation of equimpment, as well as changing heat flow of heating heat and heat of animals. After analysing technological and technical solutions of typical milking parlors, there were receiwed the following values of initial and model parameters: coefficient of the heat transmission of the walls - 0,5 W/m²K and roof - 0,25 W/m²K; specific area of external barrier that accumulate heat - 18,5 m²/kW total heat flow of animal; specific heat losses through the external barriers of the milkign parlor and losses with ventilation (heat losses for 1 kW flow of the total heat of cattle, when temperature difference between inside and outside air is 1 K) - 0,022-0,039 1/K. While working out the model, the following results were receiwed: when outside temperature is -20°C and required air temperature in milking parlor is 15° C twice a day for 3 hours, the heater, of 1,5 kW for one milking unit, must be turn on. Between milking inside temperature decreases to 6° C.
Sudarytas paprastu metodu sprendžiamas patalpos oro temperatūros dinamikos panašumo (matematinis) modelis, kuris įvertina atitvarų šilumos akumuliaciją, periodinį šildytuvų bei gyvulių šilumos srautą. Modelio parametrai parinkti išanalizavus tipiškų melžyklų technologinius ir techninius duomenis. Kai lauke 20°C šalčio ir norima, kad melžimo metu patalpos oro temperatūra pakiltų iki 15°C, sprendžiant modelį nustatyta: du kartus per parą po 3 val. turi būti įjungtas šildytuvas, kurio galia 1,5 kW/melžimo vietai. Tarp melžimo patalpos oro temperatūra sumažėja iki 6° C.