Backward leaning lean-to greenhouse might have advantages.
I recently got free glass and made a greenhouse with it (not yet complete) Due to the number of panes and height of panes I made a backward leaning leanto close to a fence at the best location for eastern morning light. It is on the south facing side of a fence that goes east west. BUT after making it, I looked at google images of leanto greenhouses and there is NOTHING that slopes back in that manner among the images. (Which I think is kinda weird). The neat thing is that the backward sloping roof helps bounce a bit more of the light away at midday (helps prevent overheating) but is angled so that the summer evening light comes in nicely through the roof . Sun sets in north west in summer so it comes in over the fence in the evening.
Anyone want to check it out? A forward sloping greenhouse near a typical victoria fence would be ideal for a person who is about 4 ft high. There are height restrictions. Anyway, I came up with this by accident, probably it will be useful to thousands of people. http://www.youtube.com/watch?v=Pd9xQiZxKlQ
http://www.facebook.com/media/set/?set=a.10150925789340767.477288.736625...
I will add more pictures and some diagrams as the project progresses.
Brian
Finally getting some traction on the greenhouse thing. A post in an engineering forum shows that this greenhouse design will capture way more morning and evening light in summer than a comparable lean to. Up to 80% of the evening light will bounce off the lean-to roof while at a comparable time only 20% to 30% will bounce off mine. I have a video of the light bouncing inside the greenhouse and hitting the plants in the north east corner http://www.youtube.com/watch?v=P5h38xsEsSg
Now for the social engineering part. How do I get people to notice? In Canada alone, this is worth hundreds of thousands of dollars to the economy if people actually do it.
Brian
Looks excellent; we have a similar unit built on the back of our house.
Where we are, greenhouses' main use is in early spring - february to last frost. And I am most interested in catching the sun when it is between 45 and 60 degrees. RIght now, all the windows on ours are already wide open, and I have put up screens to stop the overhead sun from turning it into an oven.
I don't have room in ours, since it is a porch, but some friends of ours (who live further north in a place where they get frost every month of the year) have one with a cattle trough that collects from the eavestroughing, and serves as a huge heat sink.
As for summer sun, I have a few mirrors set up around the garden that help catch a little bit of extra light.
Thats pretty neat, Mr Smith! I have never had a greenhouse before. have not yet ran into the ventilation issue because I only found my hinges today so no door on it yet. I plan a pond in front as a heat sink. Plants are growing like crazy in it.
A friend here has a huge greenhouse with probably a thousand plants in it - veggies and herbs. It's just massive. He built at the time he built his house (30 years ago) and has been adding on to it every year. If you could drive into it, it could park five cars - easy - and have space left over for all the garden tools. It's a wood frame structure with thin plexiglass panels. He also has gardens outside growing rhubarb and strawberries.
My greenhouse came from Home Hardware and is quite small - steel frame with very cheap plastic panels - one at the back blew apart in a strong wind. I think I have roughly 200 carrots, 35 cucumbers, and 7 cabbages growing in it. I used to have a huge veggie garden but it went kaput because of invasive weeds taking over from the embankment which falls to the water.
Yeah, I moved in in February and options for the greenhouse were limited. Would have liked to attach it to the house but there is girlfriend and her son to concider. (He has athsma). Plus the house came with a hot tub in a good potential place for the darn thing, and we had to decide whether to keep or dispose of it. I am just amazed at how fast things grow in the greenhouse. and it still does not have a door. Does his greenhouse produce all year? I sited mine for best all year light. Took about a week to chose a good place because it is not as easy as it seems.
And then I had to move all the soil because the best place was used to dump all old compostables for the last decade. I think a special tool is needed to pick the best spot. And in Feb the sun's path is a lot different and there are no leaves on the trees so there is a lot of guessing going on.
Just found a super tool to visualize the sunlight direction. Seems to be 3 rays per hour on the maps. http://www.sollumis.com/ You can zoom out the maps too and check different locations at different times in the year all at once.
No, all the greenhouses here shut down from about the second frost (usually end of October) right through to April.
Pretty well complete with the greenhouse thing and it is on instructables at http://www.instructables.com/id/Design-your-greenhouse-Lean-away-Better-... When I put it on the CR4 engineering forum to get help with the physics, first response was super ignorant, and next one was super good, but then they dried up. I suspect that the first response saw to that.
It is about an hour and a half old and luckily got featured in the living section so will get a lot of views today. 92 so far.
Some good links on that page, including building a greenhouse with old windows. I've been thinking of doing this for a while now as I have old windows in storage - but they need a lot of work before they can be used.
Also, I'm a volunteer board member for the Coasters Association here on the Quebec coast, and we have a proposal in front of us for a commercial greenhouse to supply fresh produce to these isolated communities, rather than rely on stuff shipped from far away. I have to do a review of the proposal and give my opinion. Our organization will be involved somehow, maybe in co-signing a loan, I'm not sure exactly what.
Greenhouses are relatively common here because they're the best alternatives to trying to garden in the open with unpredictable weather and bugs.
Hi, Boom Boom. The big deal with your greenhouse is siting it, they say eastern sun in the morning is the biggest deal. and that sollumis.com website is brilliant. (but I found it after mine was up) I visited a neighbour yesterday and her greenhouse was under an apple tree. Things were pretty small. I had no idea how much sun from the north I get, even though I did all that solar stuff in the past. I really think people have just followed the Jones's on this one. So many lean to greenhouses on the south of houses and you have just cut off 5% (or more) of your direct sunlight for your entire growing season! Thats a HUGE mistake.
It probably took about 2 weeks to pick the location. Run out in the morning at 6 or 7 am etc just to see where the sun is rising and what blocks each location etc and check where it goes down. But that will not help much 3 months later! Biggest surprise to me is that the runner beans that got away on me in the greenhouse survived. 3 ft + when I transplanted them, some over 4 ft tall! trailing along the ground did just fine and are still well ahead of those faster runners! that were less than 2 ft tall when I put them out about a week and a half earlier. Before I moved, there was a window replacement company down the road from me. They threw out enough old windows for 5 greenhouses every week. (A neighbour had first dibs on the throw outs and used them in upisland renovations). My glass is single pane. I would love to know the relative value of double or single pane. I know double lets in a lot less light but if it is warmer earlier.....
Seems to be lots of trade offs involved. That's why I tried to put together a "design your own greenhouse" instructable. I got free panes of glass. I wasn't impressed at first, but Now, I think it is easier than framed windows.
I don't have a big property, and I'm limited as to where I can erect a new greenhouse or two - that's part of the problem.
I'm continuing with the renovations (my third year!) and because I'm adding a "mud room" at the front, I can very easily add a small greenhouse to the side with the entrance door coming from the mud room. I'm talking to my contractor to see if there's any flaws with my design.
Well I put a lot of work into the instructable and it has helped a fair bit. It was featured recently and it is "popular" at the moment. http://www.instructables.com/tag/type-id/category-living/?sort=POPULAR (this changes every day so probably it will be something else tomorrow.) It is up to 1650 views now. Here is an interesting thing. "The sun rises in the east and sets in the west" has been drilled into us since we were kids. And it is true! on 2 days of the year! This shows June 15th at my place. east west is horisontal, and the rays show the sun from where it rises to where it goes down
If anyone wants to help me with physics, there is a little problem. The 15th of june is 241 degrees of time (if 24 hours corresponed to 360 degrees of circle) but it is 256 degrees between sun up and sun down on the diagram. I am pretty sure both figures are correct. What I want to find is the amount of time that the sun is north of the east west line. Any idea how to measure this? I have found websites that give sun up and sundown times and angles but none so far that tell when the sun is exactly east or west of an observer. If I can find this, it would be useful to figure out how much better a lean forward greenhouse is in summer.
Thanks
Brian
This should take you to all the formulae you need:
http://en.wikipedia.org/wiki/Position_of_the_Sun
And this PDF includes a model sun angle calculator:
http://www.pilkington.com/resources/pilkingtonsunanglecalculatormanual.pdf
(an analog calculator, I should add)I suppose the simple formula you are looking for is 180/241x hours of sunlight for that day. Though you're not just looking at the horizontal angle of the sun. The vertical angle changes as well, and that gives you more or less light depending on how your building is made.
Sorry that is too many formulae! I cannot do math anymore. It would be surprising if no scouts group or survivalist group does not already have the times of the sun being exactly east and west calculated somethere. (For compassing, setting up compasses or something like that. Thanks for trying.
I hope to put all the stuff I learned on this project into a kick ass video about siting and designing greenhouses for your local needs. If my glass had not been so darn huge, I would have made a lean to like every other attached greenhouse and that extra light would have been all lost!
I made a little model today and it indicates that in Summer, less than 12 hours per day comes from south of the east west line. It was a surprise but a pleasant one. Probably means that my greenhouse is better than I thought. If anyone has an engineering background or is into astronomy, could you verify it for me?
(In the standard notataion, east is 90 degrees and west is 270 degrees so from zero to 90 and from 270 to 360 are north of the line.)
thanks
Brian
Today Usbport on the Cr4 engineering forum confirmed what my model showed. He has used the "starry night" program to confirm that the sun spends LESS THAN 12 hours per day in the south sector of the sky. Who would have thought! Here is most of his post from Cr4
"On this date, at 53 degrees North (for Nottingham), the Sun rises at 4:48 AM at a point of 50 degrees azimuth. It reaches the due East position, 90 deg azimuth, at 8:23 AM. It transits the meridian at a civil time of 1:08 PM (the time on your wall clock).
It then reaches the due West point (270 deg azimuth) at 5:52 PM, and then sets at an azimuth point of 310 degrees at 9:25 PM. Total daylight hours is 16 hours, 37 minutes. The Sun spends 10 hours and 37 minutes in the 'South' part of the sky, between 90 and 270 degrees azimuth. It spends 3 hours and 33 minutes in the Northeast part of the sky and 3 hours and 35 minutes in the Northwest part of the sky."
He also included diagrams from the program.
It seems now that the backward sloping greenhouse is the most educational project I have ever done. Anyway, one of the recommended places for a lean to greenhouse is on the southern side of a house. However, if 10 hours and 37 minutes of sunlight (better quality sun, I agree) comes from the south and 7 hours come from the northern part of the sky, I question the advisability of putting a HOUSE between the greenhouse and those 7 hours of sunlight! Anyway, thank goodness the project is nearly complete. I had to endure the typical indifference but also some really nasty sarchastic comments. It wears you down bit by bit.
Brian
Gawd, people are dicks. I posted the same question on the solar observers yahoo group and the "smart" answers came in thick and heavy.
Thanks to the engineer in Nottingham, I already have the answer. It is surprising that an online community of 'solar observers" were unable to provide it.
I did a video (and it is not bad) to explain some of the greenhouse stuff. The only major mistake is that I put in Victoria's latitude wrong.
It is at http://www.youtube.com/watch?v=PBbTLUahWHc If you are planning a greenhouse, or just planning a garden, it is worth a look.
Brian