what does " air socks" mean in this context?

[translation]

Dubbed the Mckinney experiment, this unique Wal-Mart, is the proving ground for 26 different energy-saving trials. For example,in the winter, used grease from fried chicken will be combined with used oil from the auto center to heat the store. In the summer, huge air socks get cold air closer to customers cutting AC cost. Over the next 3 years,Wal-Mart will carefully study all these experiments.

thanks.

[Casiopea]

View here: http://www.airmax.net/