Usually panasonic projectors have fan speed option. If you are not using the economy mode , then it should be in bright mode where the lamp is much brighter than normal, hence the projector fan runs at high speed and so is the fan noise. this mode is used when light ambiance is uncontrolled.
Check this option in the menu . Do not block the ventilation of the projector . This may in turn cause the projector to run hot
thus making the fan to run fast .
Hopefully you can cut the fan noise by turning to Eco mode.