How far east of true north would be acceptable? « Alternative Technology Assn Forums

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How far east of true north would be acceptable?

(13 posts) (8 voices)

Started 6 years ago by FreddyBare
Latest reply from FreddyBare

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FreddyBare
Member

I'm having some major dilemmas after my earthworks man thought my house was 90deg different to what it is so if I build my house true north, I will have an area of about 20m2 that will have to have deeper foundations due to them bearing on fill. If I was to orientate the house say 5-8deg to the east I would have about 4m2 of fill to contend with. Would building this amount to the east have a dramatic change to my passive solar design? I have read somewhere that 5deg to the east is optimal, but I can't seem to find the article/forum that I read this from.

My house is in Greendale, Victoria 650mts above sea level, probably about 8-10mths of heating weather, I get afternoon shade at about 4pm everyday due to the forest to the west of the site. If anyone want to critique my plan I'm happy to post it online.

Thanks in Advance

Scott

Posted Thursday 7 May 2015 @ 7:32:05 am from IP #
Johnnojack
Member

Dont be so If you have a forest to the West then moving a bit East is a good solution.

Posted Thursday 7 May 2015 @ 1:17:08 pm from IP #
Eco
Member

Your Home Technical Manual does not think that small deviations from true North is much of an issue.

http://www.yourhome.gov.au/passive-design/orientation

"Orientation does not have to be precise: there is a degree of flexibility."

Posted Thursday 7 May 2015 @ 11:37:45 pm from IP #
FreddyBare
Member

So orientating to the east shouldn't matter, especially seeing as I have shade in the afternoon? This is quite a dilemma for me.

Posted Friday 8 May 2015 @ 7:31:40 am from IP #
FreddyBare
Member

My only concern with that article 'Eco' is that it is referencing to existing dwellings, obviously, I have the liberty to build where I want, but with the impetus that it could be detrimental in some shape or form. I really need to know is true North the best orientation or is east of north the best? I'm in a cold climate, I really don't want to get this wrong for a few thousand dollars.

Posted Friday 8 May 2015 @ 7:37:46 am from IP #
Chip
Member

According to an architect friend in cold Canberra which is at about 650 m ASL, up to 10 degrees either side of north isn't going to make much difference. If you tend to have a few foggy mornings then going a little west might be optimal, if in your case you have some afternoon shade then going a little east would be optimal. What makes a bigger impact is whether early or late sun shines on a wall that runs at right angles to your northern wall.

No house design is perfect for every day so whatever the design compromises, our houses need to be "driven" after we move in. Where we place furniture, the timing of opening/closing curtains, the colours we choose for the vertical and horizontal surfaces that sun lands on are all factors that can be adjusted to make best use of situation and weather.

But if you would prefer to go to direct north and have the space and flexibility wrt boundary, a backhoe could probably do another metre of cutting into a hill or your engineer may sign off on slightly bigger edge beam together with a couple of backhoed pier holes down through fill to original ground. In our case piers didn't need steel and were poured to bottom of slab/edge beams at least a day before main pour.

Posted Friday 8 May 2015 @ 9:07:05 am from IP #
sun2steam
Member

Look for instance here: http://www1.solmetric.com/cgi/insolation_lookup/lookup.cgi
They unfortunately do not have data for Australia but plenty of data for the US. For a rough guess it is sufficient if you check out a US location with a similar latitude as your dwelling and swap East and West.

Eg.the data for Long Beach, California could be used for Sydney as it has about same latitude North as the latitude South for Sydney.

As you can see the system is very forgiving with 95% position efficiency for angle of North +- 30 degrees and even straight East or West is still good with about 80% position efficiency.
Just add a few more panels (it is possible to have more nominal 'power' from the panels than the converter size. Google oversizing PV) and you will be fine. Panels are cheap. If you build a house they represent just a very tiny percentage of the total cost, probably less than the cost of changing a higher quality of bathroom tiles. And bathroom tiles produce no electricity.

Did you design the roof that you can install a large number of panels, at least 5 kW?

Posted Friday 8 May 2015 @ 9:09:21 am from IP #
FreddyBare
Member

My panels are on my shed and face due north, I appreciate all of you input in relation to my possible new orientation, Chip you have given me new found enthusiasm for the ability to alter my plan, and I thank you. I'm leaning towards a 6Deg angle towards East, as that will save money and possible energy for heating my house. Thanks to all of the ATA crew, you guys are invaluable.

Posted Friday 8 May 2015 @ 9:29:16 am from IP #
bashworth
Member

I did some solar panel calculations that indicated that 30 degrees of true north didn't lose much efficiency. See http://www.anewhouse.com.au/2012/01/solar-panel-alignment/

Posted Friday 8 May 2015 @ 10:44:33 pm from IP #
FreddyBare
Member

I've moved the house 5 deg east, thanks for the help People now that I'm removing my building envelope, I'm even thinking of a redesign, My architect loves me, NOT, haha

Posted Thursday 28 May 2015 @ 11:34:17 am from IP #
David
Member

bashworth said:
I did some solar panel calculations that indicated that 30 degrees of true north didn't lose much efficiency.

30 degrees I know from my system that I installed here that they drop off quite badly later in the day for data and history would not matter much for 5-6 degrees but 30 degrees.

Note: EST only ever used for time reference (No DST).

http://pvoutput.org/list.jsp?id=14923&sid=12798

Have a look at how generation drops off when your at 30 degree east of true north, mind you I had no choice for this system, our future farm house construction a different story.

Posted Friday 29 May 2015 @ 7:56:49 pm from IP #
Russell Moore
Member

When we built in the early 80s, PV wasn't on our horizon owing to the costs at the time.

We were also assured that angling the house a little to the east would help warm the house earlier in the morning, so we built about 6 degrees east of north. Not really sure if it helps, but now we have PV as well, and there appears to be little if any difference to others PV orientated true north.

Posted Sunday 31 May 2015 @ 12:56:43 pm from IP #
FreddyBare
Member

Thanks for your replies, I'm moving forward with more confidence now due to all of you responses

Posted Sunday 31 May 2015 @ 1:05:22 pm from IP #

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