[jeff5may]

This is not an equal comparison. The bphe is rated for up to 17000 btu at whatever flow rate v.temp, whereas the coax he is rated for half that capacity under normal heat pump operating conditions. The plate he is $100 plus shipping, I'm guessing it would do roughly 3 times more heat transfer under the same head pressure (based roughly on price). Surplus city has the next size up coax exchanger, rated for 1.7 tons (20kbtu) for $43 plus shipping. Compared to this coax exchanger, the bphe would still probably be more efficient. But plate exchangers have more maintenance needs than coax exchangers and efficiency would eventually drop to below the coax exchanger due to fouling. In contrast, coax exchangers take very little maintenance because they don't have little nooks and crannies for crud to settle or grow in.

In my dealings with Surplus city, they have never charged an outrageous amount for shipping. They just don't calculate shipping on the website until your order is completed because they usually ship all the smaller items in one box. Also, they sell many large, heavy items that can only be shipped by freight. If in doubt, just call them. They can supply you with white papers and such for your items as well, you just have to ask for them.

Dremd just ordered one of the 1.7 ton coax exchangers for his bayou cabin cooler project. It was around $80 shipped. He posted his surprise at the unexpected "heavy-dutyness" of the exchanger in his thread.