Monday, August 30, 2010

Connecting a PAHS Air Tube

Today I hooked up one of the upper air tubes for the Passive Annual Heat Storage system. The PAHS system uses eight 6" diameter tubes to bring in fresh air and remove stale air. Four lower tubes enter through the back walls at floor level, and four upper tubes enter through the roof.

March 19, 2010, Shortly After the Roof Was Poured.

This image shows all the tubes protruding through the roof. The four smallest and shortest vertical green tubes protruding through the roof (some are hard to see) are part of the upper PAHS air tube system. Each of the short vertical tubes will be connected by a horizontal tube to one of the long green vertical tubes coming up from the ground behind the back walls. The two sets of vertical tubes could not be connected by horizontal tubes until after the backfill was put in place and settled, because the moving soil might distort and break them. (In the photo only three long tubes are visible; two of the tubes are adjacent to each other at the interior corner.) For example, the long tube closest to the viewer will be connected to the short tube to the right of the closest large tube. These are the two tubes I connected today.

Cleaning Wet Clay Off the Tubes and Elbows

Finally we've had no rain for the past ten days or so, and the top three-inch layer of backfill clay is dry. But below that, it is a wet muck from the continuous rains we've had all spring and summer. A couple hours of digging around the two tubes and between them with a round shovel, and I was ready to measure and fit the tubes and elbows together. The last step was to clean all the connections and glue them together.

Connected Tubes Ready to be Covered

Now the air-tube circuit is complete. The closer vertical tube is coming up through the roof. The bottom of the horizontal tube is about 18" above the top of the roof. (It's hard to imagine that there's an office below this tube.) The outside of the back wall lies just to this side of the back connecting elbow and the long buried vertical tube.

The PAHS insulated umbrella will run about two to four inches above the top of the horizontal tubes. Over the roof of the house, the insulated umbrella will consist of two layers of 2.5" styrofoam sandwiched between three layers of 6 mil clear plastic vinyl.

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