heat in the kitchen

I am looking at adding a small place 20ft* 55ft, (plus a dishroom/restroom and storage in the back!)
my question is I am looking at this type of oven and I will have sort of an open kitchen, how can I control the keap and keek the dining room cool?
was thinking of making an insulated box to help contain the heat…

http://cgi.ebay.com/Garland-Double-Stac … dZViewItem