Mystery Heat Exchanger

A friend recently gave me a cupro-nickel heat exchanger. This is a classic single pass shell-and-tube HEX, with 74 approximately 0.25 inch diameter tubes inside a 3.5 inch diameter shell. The overall length of the HEX is about 17 inches. The tube flow fittings are 1.5" and the shell fittings are 1" diameter. Each end is stamped with "YR CO" and the number 109429. It was originally intended to be used to augment heat in a swimming pool and appears to support a reasonably high flow rate through the tubes.

I cannot find any information on this unit and need to know its approximate BTU transfer rate at, say 180 degree shell water temp flowing at 6 GPM, with 80 degree F input water to the tubes, flowing at 10-15 gpm.

I'm a satellite design engineer and this is a bit outside my normal daily calculation....

If anyone has seen this HEX or knows its specifications, or can give me a thumbnail calculation of its capability, please contact me here or off-list at "bill at satcomresources dot com" (trying to keep the spambots from finding this addy!).

Thanks!

Bill