> > >Now I'll offer my favoured system.
> > > >
> > > >Outside air is hot in day and cool at night. Houses (brick, block, and
> > > >concrete ones) have a lot of thermal capacity. If ventilated heavily
> > > >at night, the whole structure is cooled, and day time temps stay much
> > > >lower. Biggest temp drop I ever achieved this way was 10C! All for the
> > > >cost of a couple of 12" fans.
>
> Where were the fans? The attic? Blowing from where to where?
All I did to get upto 10C was put a 12" deskfan by an open window, with a 2nd sash open for through draught. It was basically test setup no 1. There was no attic venting there, and no automated control... do it all properly for a better result. Note 10C was the max drop I got,
6C was more typical, just from that one measure. The idea of a sash window (the Georgians had them up to the ceiling) is that
> when both halves are opened, hot air in the room rises to the ceiling and
> floats out of the window with cooler outside air coming in the bottom.
indeed - but that can be improved on. That original approach equalises mid air indoor temp to outdor temp. Tops only approach equalises top indoor air to outdoor air, thus giving you another 1-2C of benefit.
If the "earth tube" is slanting away from the house and the house is on an
> incline condensation runs out.
if.... Even on a steep slope it wont all run out.
As with the earth tube, controls need to be in place to detect whether it is
> worth drawing in outside air either for heating or cooling.
One thing I found was proper control makes a big difference.
Regards, NT