DIYbanter - View Single Post - Windmill nonsense.. Tilting at Wind mills

The Natural Philosopher

wrote:
Mark wrote:
On 6 Jul 2006 14:08:17 -0700, wrote:

Small heat gains and largish cooling can be done this way with low
equipment cost and even lower energy use. Happy to give you more
details if you like, though I presume you know the strategies I mean.
Please do...

Mark

ok. The main effect one takes advantage of is thermal storage in the
house structure. This means the indoor temp doesnt swing up and down as
much as outdoors does. Outdoor temps are higher in daytime than
nighttime, and of course vary from day to day. This gives us 2
opportunities for free heating and cooling.

1. In spring/autumn one can ventilate the house during afternoons to
raise interior temp, closing ventilation at other times. The simple
system I used could gain 2C this way.

2. In summer one can ventilate at night, when it might be 10-15C
outdoors. This cools the structure down. During the following day the
house wont heat up as much. The max result of this system was 10C
cooling, with 4-6C being typical. 4-6C is a lot of comfort gain.

Compared to conventional heating and cooling this approach takes very
little energy to run, saving money and energy and improving comfort,
especially in summer.

Essentially this is how we actually work.

That, plus opening the curtains by day except in summer maximises solar
gains..I have been TRYING to indicate to SWMBO that keeping the windows
SHUT in summer actually keeps the house cooler...along with the fact in
winter that thermostats do not control how FAST a house heats up, juts
how hot it is when it stops..and that opening windows if its too hot
doesn';t make it cooler, just sends the oil bill through the roof..

Then theres the concept of stratification, the fatc that indoor air
tends to separate to warmer air up and cooler air down. This can be
used for another degree C of gain. For best cooling, the hottest air
should be ejected. For best heating, replace the coolest air.

Theres also loft ventilation, which would be controlled separately for
best cooling. One can also expand on this system with other low cost
low energy heat and cool options that all add a bit more gain to the
system.

Loads more that can be done as well, like heat exchanger ventilation..

You could also make something like a passive fridge, utilising heat from
direct sunlight to heat a refrigerant, and then cooling it again on the
north side of the house.

NT