You can keep your Cool Brewing bag cold just as you would keep any cooler cold. Just add ice packs or anything cold to keep reach and keep the desired temperature. A great method is to use plastic bottles of ice. This way you can just refreeze them once they thaw and there is no mess. They also last much longer than ice packs.
Fermentation bucket in foodstuff quality plastic, with lid, 42L
Bucket in foodstuff quality plastic, with lid and airlock, 42 L