gpm water flow in 1/4 inch pipe

I was wondering what the flow rate for 1/4" copper pipe was. I want to build a heat exchanger and need to know the flow rate. I tried to look it up on the net with no luck. Thanks

tube

First we would have to know how you are measuring the tubing. Small sizes of copper tubing are ofter referred to by their o.d., in which case your 1/4" copper would be 1/8" plumbing size, rather than plumbing 1/4" which is 3/8" o.d. Next, the pressure is a determining factor, as is the total length including the allowance for bends. Without all those factors you cannot even approximate the flow, although you can be sure it is very little. Normally heat exchangers with those small tubes use a large mainifold with fairly short lengths of the small tubing between them.