Date:         Wed, 11 Jul 2007 14:03:26 -0800
Reply-To:     Troy <colorworks@GCI.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Troy <colorworks@GCI.NET>
Subject:      Heat exchanger for hot showers
Comments: To: gezapolony@SBCGLOBAL.NET
Content-Type: text/plain; charset=Windows-1252

Hi there:

If you take a look at that link I posted, you'll see there is more to this system then just wrapping some copper pipe around the manifold. Yes, I do agree that wrapping copper pipe around the manifold would produce hot water, the next question comes into play: how much hot water (what psi or gpm), will kind of temperature rise is the system capable of? Is there a way to regulate the system? If you ignore these problems, they are bound to come back and bite you in the butt. 

Doing a Google search for a heat exchanger produces a number of them. As I mentioned in a previous post, some of the criteria involved would be to determine temperature rise versus gallons per minute. Typically the higher the rise, the less volume produced. A way to regulate the system (perhaps a partial bypass of the heat exchanger itself) otherwise you'll end up with water that is either too hot or too cold. Finally, flow rate, which is largely determined by the pump capacity. If the flow rate is too great though, the heat exchanger will not be able to keep up. My goal was to be able to use the system for hot showers, although if you simply want unregulated hot water, then what you suggest would certainly fit the bill.

Considering all these problems, I have started to take a closer look at my current Coleman hot water on demand. Compared to the Zodi system Mike mentioned the other day, the Coleman produces 30,000 btu's versus the 10,000 of the Zodi. This is a very good thing as it can handle water that is 40° and heat it up to 100 plus degrees in 5 seconds, and still provide a pretty good flow rate. The Coleman has a few of its own problems, but that's another thread...

Troy