I am planning on "building" a Walipini, or some variation on that theme. I want to be able to produce food during the winters here in Utah.
Using the information from this thread, it seems that to the angle for the roof to get full sun at the winter solstice would be around ~64 degrees; this means that the roof would be almost 25' high with a 12' width (wanted to do 24', but that might not work that well). I think this may be higher than my house...
Are there any alternatives to a Walipini or at least the roof that would actually work? I would prefer to only use the sun for heat instead of installing a rmh. According to weather.com the average low here in winter is 27 degrees.
I was thinking of building a pitched roof, which would decrease the height by half.. but I don't know if that is the best way to go.
Eaton Wright : I would get a second opinion on the sun angle, This is a little outside my area of knowledge, but I understood the winter sun should hit the glazing
on the roof at right angles, increasing the angle past your North Latitude will promote overheating during the most active part of the growing season. This would be the
smallest amount of glazing (shed roof)and the height of your back wall would be reduced, It makes no difference to the height of your back wall but Walipinies are ether
earth bermed, or dug out pits to use the earth as a Thermal flywheel, you get more bang for your buck with the increased protection of the pit thermal flywheel and your
building is not as high and you will need less insulation !
Your average low seemed high to me so I checked, and that is a good temp for Salt lake city, but you will be colder at a higher altitude, so make sure the average temp
accurately reflects your local conditions!
Also the percent of every day (on average ) that the temperature is below freezing is 60% that would be at night while the sun is not shining ! That is a lot of thermal mass
that must be heated during the shortest days of the year !
It is very possible that I have mis-understood your plans, and there is a good reason for increasing the angle of your glazing, but do get a second opinion! Perhaps Search
a few more Permies sites ? I will sit back and watch this one for developments
Can you go to the Permies Toolbox at the top of this page to the right of the spinning sun, click on my profile and add your location etc. look at your 'Authors Name'
space, and L@@K at mine! More information means the advice you get is more accurate, and may help you find a near neighbor with Greenhouse/ Walioini experience!
For the Good of the Craft ! Big AL
Success has a Thousand Fathers , Failure is an Orphan
Walipis were designed for the high mountains in the tropics, they don't translate to higher latitudes as well as you would hope.
There are lots of lower cost greenhouse ideas for your latitude. I would do a partially underground hoophouse with double layer poly. If you get 3 feet down, berm the north side and ends with the remains, insulate the berm to tie into the mass (like an earthship or PAHS/wofati), and do the normal black water barrels for additional mass--you should be able to handle those temps if you have daily sun. You will still need to add heat if you have long cloudy spells.
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Location: Salt Lake Valley, Utah, hardiness zone 6b/7a
posted 4 years ago
I have read recommendations that the angle be set a little toward the winter side of the equinoxes, rather than for the winter solstice, unless you are going to install lighting. With the short days, most plants will go dormant anyway, so optimizing for season extension might be better.
Two problems with Wasatch Front locations: most hillside lots are facing East or West, and, Ice fog (which we haven't had to deal with for a few years, but which can last for many weeks, once it sets in. Ice fog is usually only a problem from November through February and requires snow cover.) If you want to overwinter cold sensitive plants, you will have to invest in some sort of supplemental heat.
The high altitude and dry air make for very sharp contrasts, black or white, no shades of gray, i.e. shade tolerant plants don't necessarily do well in the shade here. Translucent glazing would provide a diffuse light that would be beneficial throughout the year.
Consider applying wofati techniques, particularly insulating the surrounding soil.