Friday, November 13, 2009

New Idea for Heating Domestic Water

Energy Alternatives has come up with a new design for heating domestic water.  Their design pipes water/antifreeze through several PEX pipes that are suspended in the attic ridge roof vent. 

The water heated by the PEX tubing is passed through a heat exchanger coil in a domestic water preheat tank.  The domestic water is preheated in this tank before it goes on to the regular water heating tank.

No real data is given on performance, and I suspect that for many climates, this is a three season heater at best, but it does offer an interesting alternative to solar, and it keeps the external look of the roof unchanged.

One article suggests that the cost of a 40 ft section of the PEX ridge vent assembly might be around $300, and that a full kit including the preheat tank with heat exchanger might be about $3100.

Here are some thoughts about DIY implementation of the ridge vent design that could (I think) be done for less than $1000 -- maybe substantially less.

Thanks very much to Chris for finding this and suggesting it!


1 comment:

  1. I would think in more humid climates that this system would be prone to condensation at times. Perhaps if the PEX were placed to the sides of the vent, over the shingled area, any condensate would just roll down the roof.


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