Air flow pattern in an enclosed Japanese dairy house with push and pull low profile cross ventilation system

Abstract. For Japanese hot summer an enclosed dairy milking free stall house with low profile cross ventilation (LPCV) was constructed as to prevent from heat load. The air flow pattern was investigated by computational fluid dynamics (CFD) and measurement with three dimensional ultra sonic anemometers as to find out suitable control with baffle, inlet damper and fan rotation rate. The suitable location of baffle was 9.5 m from the inlet sidewall and the height was 2.5 m. The suitable ventilation condition for summer was that the inlet damper angle was 15º downward from horizontally, the up stage inlet fan rotation rate was 30 % and down stage fans were stopped and the exhausted fan rotation rate was 60 % from the view point of uniform air flow velocity more than 2.0 m/s and electric power saving. In winter ventilation it was seen for suitable condition that inlet damper angle was 60º toward to up and the incoming jet speed was 0.5 m/s.