depends on which way you hook them up as to if they are parallel flow or counter flow. there is yet another type of heat exchanger called a cross flow heat exchanger but you don't see these very often. i experimented with something similar to this by putting my IC in a bucket and then had the recirc flow go from top of the bucket down over the ic and out the bottom. but i now brew small enough batches that i just put the kettle in the fridge overnight