Posted in Sustainable Homes and Living

Off-The-Shelf DIY solar water heating — Version 2

I’ve had a bit of a reset on the Off-The-Shelf solar domestic water heating system.

The idea of this system is to provide a very easy to build DIY solar domestic water heating system that uses off the shelf collector, tank, controls, etc.  — a system in which you just install the off the shelf components rather than building your own collector and tank.  The objective is to keep the total cost to about $1000 (compared to about $8000 for commercially installed systems).

The first version of this system used plastic mat style pool heating collectors installed in a horizontal format and at a not very steep tilt angle.  I’ve decided to change to a vertically oriented mat style pool heating collector installed at a steep tilt angle.   The advantages include an easier and cleaner installation, better cold season performance, less susceptibility to summer overheating, and more flexibility in trying a vented glazing system to increase winter performance without overheating.

The new collector

The new collector is a single 4 by 10 ft pool heating collector mounted off my existing Solar Shed.  The vertical mount appears to be more secure and less subject to sags and folds — it basically hangs from the upper manifold with straps to secure it from winds.  Its easy to install and appears to be quite secure.
More collector area could be provided by going with a 4 by 12 collector and/or adding a 2nd collector.

The same Softank that was used on version 1 is retained.

The plot below shows one sunny days performance.

Sunny day performance

On this sunny October day, the collector heated the 132 gallons of water from 83F to 110F.  It was mostly sunny with an ambient temperature of about 70F — so, this is quite nice performance.

For later in the season when ambient temperatures are lower, I intend to try some form of vented glazing to see if the winter performance can be improved over that of an unglazed collector — stay tuned.

All the details on the build and performance to date…

If you have any ideas for improving this design, please let me know.

Gary

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