Wednesday, July 20, 2011

Converting a Clothes Dryer to Use Solar Heated Attic Air

Randy has done a really interesting new project that reduces the energy used to dry clothes at his house by a factor of five!

His scheme converts a regular dryer to use hot air supplied by his unique attic solar heating collector instead of heating the air within the dryer.  A duct from his attic collector supplies air to the revamped intake of the converted dryer.  The dryer exhaust air is vented out through the wall in the normal way.

The converted dryer on the left and the new intake ducting on the right.
The upper duct connects to the attic solar collector.
Dryers are major users of energy in homes. A Canada study shows that dryers typically use 930 KWH a year to do 416 dryer loads (2.23 KWH per load). Nearly all of this heat energy is simply expelled outdoors (wasted). In addition, as the dryer vents air outside, it pulls fresh air into the house which has to be heated or cooled (depending on season) to room temperature -- this can easily add another 300 KWH plus per year.    Since refrigerators have become much more efficient over the years, dryers now stand out as the applicance using the most energy in many homes.  It is amazing to me that Energy Star has taken no action in this area -- but, I guess that's another story.

For all the details on Randy's dryer project...

I've also added a new section that gathers together several ideas and projects that save energy on clothes drying ...

Some highlights on Randy's dryer conversion:

The silver duct on the right is the dryer air inlet.
It takes air from the dryer cabinet on the lower right, and supplies it to the drum.  The idea is to change this so that
the air source is the attic solar collector.
Randy pluged the normal air inlet (lower right), and
added the 4 inch connection for the new attic air source.

The upper duct is the new air inlet ready to be hooked up to the attic air source.
Lower duct is the normal dryer exhaust vent that goes to the wall.

The duct that brings the hot air from the attic collector
down to the dryer inlet.

The temperature on the right is the attic collector temperature.
Temperature on the left is the dryer inlet temperature.

Drying a full load of mixed clothes takes 90 minutes, and uses only 0.6 KWH.

Gary July 20, 2011
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