Re: passive solar must face south?

 Hello Ryan;



Not exactly, glazing facing generally south is the most basic factor,
but still means little unless all aspects of the design work together
successfully. A well integrated design is the key.


There is always reason to use intelligence and knowledge
of the site climate when designing a home.  Every building
is a passive Solar building.  Some are just real bad ones,
because the designers incompetently ignored the climate.

As far as the 27° E of S goes, it's a very good orientation.  I am not
familiar with the exact figure from your area, but my guess would be
that the optimum orientation would be about 12° E of S.  You want it
to collect enough early morning sun to take the chill off early. You also
want it facing away from the late afternoon sun.  Remember that the
angles will be the same on Sept 21st when it's hot, as on March 21st.
I would rather have "direct gain" facing 27° E of S, than due south.


There are general approaches, but any building design (including
passive Solar design) is far better when done based on the specific
parameters of the project. This means, not only the site and Solar,
but also the myriad of factors of the occupants, their lifestyle,
budget, etc. Living with passive Solar is an experience. A house
will do things on its own.  Like it has a life ;O)  Compatibility is
a consideration. The analogy I like is "A sailboat, compared to
a power boat"

Your site sounds real easy.....in terms of Solar gain orientation.


Of course. Just as it is not usually optimal to heat 100% with
Solar, it is also seldom optimal to heat 100% with natural gas
or any other conventional fuel.


Getting a good gain area is the easy part. You need a floor plan
which doesn't require hardly any west or north facing windows,
and still works and looks great. You need to have a way to keep
your south facing windows from overheating the house. Sept 21st
you want to block the gain, and/or vent. March 21st you want to
store the heat for later use, but still not overheat the house. This
is all worked out, just like every other aspect of the design, as the
whole thing takes shape.  It should to be a heating machine, but it
has to feel like a home. I have always found the joy/challenge of
passive Solar design to be melding it into a 'style' which says
something other than "Look at how Solar I am"


  My experience from nearly 200 design jobs has been that it is
the norm to not have a clear, open, long, due south exposure looking
out at the perfect view.  I find the 'front' facing north to usually
be an advantage (for a great floor plan, etc.).  It puts your large
expanses of glass away from the 'street' and back in the more
private areas of the lot, and of the house.


You don't need to be trying to design a house yourself. You need to
find someone who is good enough at it to do it for a living. Find Solar
houses in your area which you like, and meet with the designers. Take
advantage of someone else's experience.  It is way too involved to
ever learn exactly what to do on a forum like this. We can be general,
and can tell you a lot of what not to do, but you need a building design
which integrates your needs, living space, structure, and passive Solar
into one, and that takes many hours of professional work.

Laren Corie
Passive Solar Building Design Since 1975 (retired)

 
A lot of the information l have read on solar, heating, etc. state
homes should be positioned with the long side facing south. This is to
take advantage l assume, of the suns heating ability. In todays world
of much higher insulation in the walls and ceiling and low E windows,
is this still an absolute? The reason l ask is the place we would like
to build our new home is on a narrow ridge that limits the placement
to long side facing west.  This is also the place for the best
views.The area  also has temps. in 95-105 range in summer. The solar
panels can be placed facing south and that is not a problem but l am
still concerned about the house. Any comments are greatly appreciated.
    Thx, Ernie
On 09 Jun 2003 10:47:08 -0600, tunaNO@SPAMindra.com wrote:

 if you don't need the suns heat in the winter, but need cooling in the
summer, get it out of the sun.

--
Steve Spence
www.green-trust.org

 Yup, all depends on where you are located.

In the "temperate belt" - around 35 degree latitude, say -  you need winter
passive heating, so you have the maximum windows facing (true) south and you
have overhangs to shade them in the summer. On north walls have as few
windows as possible. If you must, make them very small. I built such a house
that was 80' east-west and from 25' to 35' deep - north- south. The 25' deep
part was comfortably warm after 4-5 hours of sun but, deeper than that, it
was always quite cool at the north ends. The max north-south distance
depends on the heights of your south wall and your windows.

Remember also that magnetic south is not true south. At the 35 degree
latitude, true south is about 16 degrees east of magnetic south, so a little
south-south east is the way to go.  If you have a lot of sun in the
afternoons and evenings, a west or south west facing room with large windows
might get hot, so plant trees if you need to and can.  Morning sun should be
less of a problem, since things should be cool then, unless you live in a
humid zone.

Good luck

Sd