re: zoned passive heating
2 mar 2003
>let's take an single story ranch home, say 70 x 30...
you might enjoy a lower surface to volume ratio with less money and heat
loss, eg a 48'x48' or a 2-story 32'x32' house. where would you built it?
>one side is heated by collecting heat and storing in water in the attic.
harry thomason designed an "a-frame swiss chalet (house number 4) like
that around 1970. it didn't work well because the only polyethylene film
he could buy for the "pancake thermal mass" in the basement ceiling had
lots of pinholes. i believe that has changed these days. israelis fill
poly film duct with water to store heat in greenhouses.
>one tank in the attic, and a heavily insulated tank in the cellar or crawl
>space. close the vents in the winter and open in the summer. high
>insulation in the flooring.
you'd have more airflow on summer nights if cool air came into the basement
and left at the top of the house. it's easier to insulate a boxful of water
than a whole floor...
>at say, 8pm, the water drains via gravity or assisted, into the cellar tank
>finned tube, plumbed to the "top" of the cellar tank, allow heat
>to migrate via thermosyphon to bedrooms at night providing heat.
you might put most of the basement thermal mass in a 4'x8'x8' epdm-lined
plywood box, with polyethylene film ducts between rafters, laid flat over
welded wire fencing and filled with an inch of water. with enough "radiator
surface," you can heat the rooms above without any fin-tube.
>a pump, operating via pv, returns the water to the upper attic tank
>in the morning as soon as the sun starts shining.
with a transparent south roof and a reflective north roof.
>in the summer, attic heat gain would be collected in the water with the
>water being returned to the lower tank (where it is colder / cooler) and
>the heat allowed to dissipate.
you might put lots of insulation in the attic floor and ventilate
the attic from soffit to ridge during the day and use the basement
ducts to collect coolth at night...