Thermo-siphoning combi systems for solar hot water.

[Jeffrey Morrow]

Below is a link to an in-depth article on solar hot water systems plumbed to thermo-siphon with standard backup systems, and to work in combination with in-floor radiant, pool heat or snow melt applications (combi-system). 

This article shows the trick to installing hot water systems that naturally move hot water from the solar tank to a backup tank, with just a few plumbing tricks and a virtually no additional cost (one check valve!). 

As alternative energy educators, I thought you'd enjoy seeing the latest tricks and tips from the field.  The simplicity of design and installation is remarkable, as is the fact that this style of connection is absolutely fail safe and fool proof. 

The goal is to improve performance at lower cost.   Here it is.  The equipment for this system costs around $3,000 new, and can be installed by a reasonably competent handyman in about two days.

The key to this system's operational efficiency is the evacuated tube collector.  Evacuated tubes simply run hotter for longer periods of the day than flat plates.  This fact is known in the industry, but not accurately reflected in SRCC ratings.  This because the SRCC rates flat plates and evacuated tube collectors under 'high noon' conditions.  Flat plate collector performance falls off sharply under low light, diffuse light, wind or cold.  Evacuated tubes do not.  I'd be happy to share data that shows flat plate verses evacuated tube performance under identical conditions during winter operation.

http://www.solarheatexchangemanufacturing.com/NewFiles/Solar%20Thermal%20Thermosiphoning%20Combi-Systems.pdf

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Jeffrey Morrow
Solar Heat Exchange Manufacturing
1301 Jonathan Drive, Lawrence, KS  66049

(785) 218-7825 (mobile)