Solar water heating system..

[Derek Broughton]

I wasn't there :-). It sounded like that's what you were describing.

[Mary Fisher]

I described what was happening, there was no ambiguity.

[dold]

My stubby little overhang shades the wall completely at noon today. That doesn't seem sufficient. It actually looks like that might have been the design, as the shadow is at the base of the wall at 1pm PDT. That leaves a lot of wall exposed to the afternoon sun.

Maybe I'd rather have an overhang for the 3pm sun.

window sill on June 21 noon for my Moderate climate.

The Australian sites have more overhang, indicating 30% of window height as an overhang, but I think that is at a latitude of 27.

Maybe a pergola, with winter-solstice angle on the boards.

[dold]

Shade at noon? That seems to expose a lot of afternoon sun. Shade at 2pm? What shade times do you have?

Maybe that cuts down on the winter solar heating. It doesn't seem to. Winter Solstice is only 27 degrees for me.

I can't plant shade trees because of the layout of the house, but I could get away with some pergola, which would look good across the deck, and only nominally out of place across the front door, where my wife wants some more overhang anyway.

[Rod Speed]

[e-mail] wrote

says window sill on June 21 noon for my Moderate climate.

Nope in the mid 30s latitude.

[Rod Speed]

[e-mail] wrote

Nope, at any time of day.

No sun at any time of the day in summer.

No it doesnt.

Yeah, I deliberately ensured that the layout of the house would allow that.

[dold]

That would be a long eave for me. Actually, not possible, as the sun is visible down to the horizon in the afternoon. It's 6:30PDT, and the sun is still shining on the house at 1.1 degrees, according to SunCalc.

[dold]

Australia stretchs from -12 to -38. Maybe you are in the mid-30's.

I was referring to the site

"For latitudes north of 27.50S the response varies with climate."

[Rod Speed]

[e-mail] wrote

Yes, but the bulk of the population actually lives in the mid 30s.

Thats a different issue to what was being discussed, whether its feasible to have an eaves that ensures that no sun enters the house in summer, but does fine in winter.

You dont really need much solar heating at 27S except in the inland and there arent many people living there at all.

[Rod Speed]

[e-mail] wrote

6' is fine here, with the glass going down to floor level.

Its gone well past W by then here, so you still dont get any sun thru the N glass.

Most dont realise how far S the sun gets in summer, and I didnt either until I calculated it when designing everything.

I in fact get some sun thru the S glass in summer, very late in the day, just before sunset, but there is a dense run of trees running right along the S side of the house with vegetation down to the ground that means there isnt any heat.

The trees were deliberately designed to produce that effect.

See above.

[dold]

I've paid more attention to a lot about the sun motion since I started looking at solar. I would incorporate some of it if I were building a house, but there's not a lot to be done about the existing house.

I thought about azimuth as I looked out the window at the setting sun, after making that posting. At the elevation of 1.1, it's also at azimuth

300. That's still shining some light on my house, facing at a 215 azimuth. One of the pages suggests that extending the eaves isn't a practical solution for houses more than 30 degrees off due south.

At 3:42 pm, the temp was 107F today. The sun was at 54 el, 255 az. Presuming that I want to keep that light off the windows, I would need a 4 foot eave.

[Rod Speed]

[e-mail] wrote

Yeah, thats what I meant in my original, by far the best time to do it.

You can do addon solar air heaters, particularly if you are there when the sun is shining much.

The economics and practicality of the more gung ho stuff like attempting to store that solar gain in water etc is a lot more marginal.

Yeah, thats the main thing I did design wise, chose the block so that the house could be long in the EW direction and due N etc.

I chose the block so that it faces into a park right down the S side too, so the council mows it with a full tractor mower and it feels like that is part of the house. The big line of dense trees completely covers the ground in leaf litter, so no maintenance at all is required.

We do usually get at least one burst of 10 days over 100F most summers. It can be like walking into an oven some days.

Very dry tho, 5% is typical so swamp coolers cost peanuts to run.

I almost never have the cooler on after sundown, open all the doors up and let the outside air in.

Only ever have the cooler on overnight maybe one night a year at most.

Yeah, and thats very viable light wise. My 6' eave at 9' off the ground is fine, the main room with 3 8'x8' patio doors on the N is very bright in winter, so bright you need to ensure that the monitors and TVs etc have antiglare screens etc.

It was plenty light enough today which unusually had fog till about 10am and then heavy overcast till about lunchtime. We just had half an inch of rain yesterday, and the room was plenty bright enough yesterday too.

[News]

What do you mean? Some of my best friends are bees.