Balance Model to Calculate the Ventilation Rate of a Mechanically Ventilated Finishing Pig House in East China

摘要

This paper studies the ventilation rate of a mechanically ventilated finishing pig house with manure gutters from January 23th to 26th, 2016. The barn is located at the suburbs of Huainan, a city at north of Jiangsu in eastern China. Two methods for the calculation of the ventilation rate in pig building were compared based on the balances of animal heat and moisture for growing pigs. Data of temperature, relative humidity and air velocity was obtained in the interior of building, as well as the external conditions. The operational status and rotational speed of ventilation fans were monitored at six stages. The analysis shows that temperature of all units in pig house ranged from 11.5°C to 14.7°C about 30min in average, and relative humidity from 44.9% to 82.6%. The average air temperature inside the pig house was 13.7 °C, while the relative humidity was 69.7%. The inside air temperature was increased by 17.8°C and relative humidity reduced by 6.8% in average than outside. The average air velocity in the lower area of the building was 0.28 m/s. The average inlet and outlet air velocity of the pig building were 3.2 and 5.3 m·s~(-1), respectively. The directly measured ventilation rate of a pig barn was 6069 m~3·h~(-1). The average moisture and heat balance ventilation rate of pig barn was 6207m~3·h~(-1), 5880 m~3·h~(-1), and the difference of ventilation rate between directly measured and balance measured during the field experiment was 137 m~3·h~(-1), 189 m~3·h~(-1) respectively.