Sunday, March 22, 2015

Equinox: Sun and Cellulitis

Equinox is here, and things hang in the balance.
This week is a great time to re-orient yourself to the cardinal directions and priorities.
Amazing print done with a pinhole camera in Tijeras,
showing sun angles from summer solstice (high arc)
to winter solstice (bottom arc). From NOAA, 3/22/2015:

For us, most projects are on hold due to Ernie being laid up with a cellulitis infection in his bum leg. Instead of chopping firewood, he gets twice-daily IV antibiotics. We hope for improvement in the next few days, but nothing's certain.

This sort of setback always makes me reflective. Am I staying tuned to what's important, or just reacting to what feels most urgent? (More on that below).

I wanted to put out this update today, somewhat urgently, because I think passive solar is very cool, and it's important, and it's easy to neglect planning for it until it's too late.  This (the week of spring equinox) is is a good week to take some relevant observations.

You can do a lot of fancy math to figure out the optimal sun angles and thermal mass to match your heat loads.  This site has a pretty great library of resources:

However, nothing beats direct observation, and now is one of the key times to observe.

A solid equinox sun-path, and a second one (sun and moon) from close to the solstice, can let you skip a lot of the maths and work directly from your site data.

 You don't want to stare at the sun directly, but watch how the shadows or sunny patch moves along the ground and floor and other objects.  A vertical stick, or an angle wedge like the dial on a sundial, will make a shadow you can trace.  If you already have a building, just watch the sunny patch from a window as it moves across the walls and floor.
I made this papercut to watch its shadow trace the sun's path.

If you are modifying a building, adding a sunroom or whatever, you might rough in a frame and hang up some cardboard to represent the future walls and roof, so you can trace the patch from the future windows.

(The full moon is roughly opposite the sun, so a summer-solstice full moon traces a similar path through the sky as the winter sun. 
You can double-check it six months later if time allows.  Since most people only get a few solstices to observe while planning a building, and some of them might be cloudy, it pays to double up at each opportunity.  The Stonehenge builders sank dozens of log post markers before placing the permanent stones. )

At equinox, March 21/Sept. 21, the sun rises due east and sets due west.  If you are not 100% sure of the N/S axis of your property, this is one way to find it (not counting nearby hills).

Equinox also marks the average day length and sun angles for every place on the planet.  Winter days will be shorter, summer days longer.
Summer sun rises higher in the sky and traces a longer path.  The winter sun takes a shortcut, low across the sky. Shadows are longer in winter, and sunbeams slant almost horizontally.

In the northern hemisphere, the summer sun rises north of true East, circles clockwise across the southern sky, and sets north of true west. The winter sun makes a shorter arc, from southeast to southwest, staying lower in the sky.  
(In the Southern hemisphere, it's almost the same but swap the north and south directions: the sun still moves east to west, but counter-clockwise.  Australian winter days are all north-oriented, summer days have a long SE to SW arc with a northern noon.)
In the equatorial regions, "summer" and "winter" may not mean much. Your temperatures stay closer to optimal year-round; tropical conditions warrant a separate discussion.

So in the temperate climates, where most people need heat:
We can orient windows and sunrooms to admit more light in winter, less in summer, which is exactly what we want in a temperate climate to offset our seasonal extremes. 

Sunroom: vertical windows let in more winter sun, less in summer
Skylight: lets in the most light, but more in summer and less in winter.
If you are setting up a greenhouse or attached sunroom, it really pays to think about your goals.
Good insulation, thermal mass, and passive-solar sun angles can help you create a more moderate environment (protected from overheating and from frost). 
Too much glass (not enough walls) can cause overheating in summer and heat loss in winter, but it does let in more light for plants.
Different plant species have different light requirements and tolerances for extreme temperatures, as do fish, poultry, and other common indoor-outdoor livestock.

The Bucket Test:
This week is a great time to get out in your sunroom with a bucket or chalk and see where the sun actually hits throughout the day. I like using a 5-gallon bucket because it's about the right height for a seating bench.  You want the winter sun to hit that vertical face for best heat collection. So you want to get the sides as well as the top of the bench into the sunny spot.

If you place thermal mass along the shady side of the sun/shade line, it will get some sun in winter, but none in spring or summer.

If you place it a few degrees to the sunny side of that line, it will get sun through about 3 seasons but not too much in summer.

You can also do this test with a camera – set up a tripod or put the camera on a ledge, and take a picture every 2 hours or so from sunrise to sunset. Makes a good record that won't get messed up as you build things.
Our clients in Chehalis are doing this in preparation for adding a rocket bench to an indoor/outdoor patio space.

Speaking of Chehalis, please check our schedule for upcoming workshops. We have two in Canada and three in the USA between now and June.  As a change of pace, we're throwing in some natural building and plasters as well as rocketry at the Ecological Living Summit in Montana.

Please keep your fingers crossed that Ernie's infection will resolve quickly and he'll be released to fully enjoy these workshops.  Since his 2008 injury, we pretty much consider Ernie as a special volunteer, and any work he is able to do as a bonus.

We have delayed the Kickstarter launch for the Rocket Mass Heater Builder's Guide because of this situation and other reasons. Hoping the fallow time will turn out to serve its purpose, and there will be some benefits from it.  For example more and better connections to help us, and I can keep working on more rewards to offer as incentives once we do go live.

So if you'd like to help, and have good resources to spread the word, please remind me that you're interested.

Erica and Ernie