"Stand Alone" Heat Exhangers and DHW


Old 01-15-12, 03:52 PM
Thread Starter
Join Date: Nov 2011
Location: USA
Posts: 421
Received 3 Votes on 3 Posts
Question "Stand Alone" Heat Exhangers and DHW

I've seen more than a few diagrams, and read several descriptions, of DHW systems that utilize a heat exchanger that is a separate unit, and not a component of the tank itself. An example:

image courtesy pmengineer.com

I'm wondering about the advantages of such a system, as opposed to, say, a conventional indirect hot water tank w/HE inside of the tank...?

Thanks for any feedback.

Last edited by NJT; 01-15-12 at 06:05 PM.
Sponsored Links
Old 01-15-12, 04:28 PM
Join Date: Jan 2011
Location: usa
Posts: 90
Received 0 Votes on 0 Posts
Well in my own home i have used a boiler mate ( tank with coil inside) for the last 25 years and it has served me good. I have used the heat exchanger headers an commercial jobs with a 200 gal. tank 120degree water and than another header for 160 degree to a kit.
Are you talking about a residential system? You will probably have some one come along that has
more info on home use. Paul
Old 01-15-12, 05:33 PM
Thread Starter
Join Date: Nov 2011
Location: USA
Posts: 421
Received 3 Votes on 3 Posts
Hi Paul,

That's one of the things I'm wondering about, whether it is more applicable to commercial applications with high DHW usage (like for example, apartment buildings), where more storage (bigger or multiple tanks) is needed.
Old 01-15-12, 05:57 PM
Join Date: Dec 2011
Location: Usa
Posts: 67
Received 0 Votes on 0 Posts
In my house I use a flat plate heat exchanger for my 80 gal. DHW. It's a Lochnivar 4-port Solar tank with electric element in it. You really need 4 ports, 2 for HX water & 2 for domestic cold in & hot out.

Rheem has commercial hot water storage tanks with multiple ports.

Works great, has a Bronze Grundfos 15-42 on the fresh water tank side & Iron 15-42 on the boiler side, both run at once in a counter flow in the HX.

Pumps & HX have to be correctly sized for your BTU transfer rate.

GEA is a great brand HX & they have an online simulator to help pick size. OR use use cheaper brands & go double on their advertized rates.
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: