Hi All,
Thanks for all the explanation, since the wind turbine efficiency is proportional to TSR, does it means that HAWT has higher efficiency than VAWT?
The "Higher TSR is more efficient" business is about a geometry issue mainly characteristic of the typical HAWT - which is a wing flying in a circle at right angles to the incoming wind, extracting its torque by diverting the air sideways. It doesn't necessarily map to other geometries.
VAWT designs have their own peculiar issue - having to fight their way upwind for part of the rotation. That tends to make them less efficient than HAWTs - though by how much depends on their geometry (especially how they handle the upwind part of the trip). But though they tend to be less efficient (wind-to-horsepower) than HAWTs, there are some designs where the efficiency is still very good.
VAWTs have other advantages that may make them attractive in some cases - especially for turbulent sites.
but I heard from few VAWT supplier, VAWT can produce more than HAWT is that true? Beside that, how do we calculate the efficiency of wind turbine?
Sounds like somebody selling them, all right. B-) Not sure what he's talking about. For a given cross-section presented to the wind, a HAWT will normally collect more power than a VAWT. But a HAWT typically presents a circle to the wind while a VAWT typically presents a rectangle, intercepting more area. (I once did a back-of-the-envelope calculation which suggests that a Savonius using the patented optimized profile, the same diameter as a really good HAWT, would only have to be about 12% taller than the diameter to collect the same power.) Perhaps he's talking about the possibility of making a VAWT that is as wide as a HAWT and the height of the tower. B-)
One of the downsides of a VAWT's typically lower efficiency is that it requires more horizontal support for a given amount of power collection.
Most of the people here build HAWTs because they are easier, especially if you want to mount them on top of a tower, than a VAWT of equivalent power. Putting something up in the air a few tens of feet gives it access to faster, less turbulent, wind. Available power goes up with the CUBE of the wind speed so wind a bit faster is a LOT better.