I think that a barraca lanera is more like a giant warehouse or complex.

Con el objetivo de armar localmente los vehículos, General Motors alquiló al empresario lanero Travella una barraca de lanas ubicada en la calle Garay N0 1.
http://www.asociacionchevrolet.20m.com/his033.htm

La Corporación Buenos Aires Sur alquiló por diez años el edificio donde hoy funciona el emprendimiento: las instalaciones de una barraca lanera abandonada ubicada en la calle Pedro de Mendoza 3825, con vista al Riachuelo, en donde la empresa invirtió 2,4 millones de pesos en refacciones.
http://www.taringa.net/posts/noticias/2303408/Madres-de-Plaz...

Every single kilo of wool we deliver passes through the hands of our staff at our Trelew facility, in the heart of the wool industry in Patagonia.
http://www.dewavrin.com/Wool/Argentina

TRELEW (Wool Combing Plant) - ARGENTINA
This new facility is the most modern plant in the american continent. COSU-LAN produces approximately 5 million kgs of tops ranging from 17.5 micron to 22.5 micron.
http://www.gschneider.com/index.php?page=woolplants

Like this:
http://images.google.ca/imgres?imgurl=http://www.framptonons...

This link and others suggest that a Barraca Lanera was much more than just a place to store wool. I coincide with Michelle that it was a place where processing took part that included storing, and machinery in as long as the industrial revolution brought them in. One must consider that hese buildings are from the 19th century or before. This would explain the size of some of these buildings, even 2 or more stories.
researching in the english (british and Australian wool industry of those times I came about the name "Woolen mills". I believe this is most probably an equivalent. The problem is not finding enough information to what activities went on in a Barraca Lanera.