Abstract
This paper describes the noise distribution and its characteristics of the hot air heater used in the vinyl greenhouse. The greenhouse and the heater are shown in Fig. 1, 2 and 3. The noise source is the axial flow fan attached to the heater.
The noise level in the greenhouse is 98-67dB(A) within about 10m from the heater, but less than 55dB(A) at the opposite end of greenhouse. The noise level at the outside of the greenhouse is over 50dB(A) within 20m from the greenhouse.
The high frequency noise decreased with the distance from the greenhouse, but the noise of 200-300Hz caused by the axial flow fan remains high. The effect of noise reduction by vinyl film is very little.
