halifaxearthtech: photo by Lykaestria from Wikimedia Commons (Energy)
This is a project I've been meaning to do for some time. I hope to give these away as (quazi-gag) gifts or perhaps sell them legitimately. A bicycle wheel is repurposed to be portable thermal mass, that you can place beneath a sunny window to store and release those warm rays on wintery days.



I'd had some cob saved from a project two years ago. All I had to do was just add water. The clay came from the Bay of Fundy mud, I'd bought some sharp masonry sand and used for straw some empty kale seedpods left over from harvesting kale seeds for Annapolis Seeds . I used 50% clay, 22% sand and 30% parts straw, if you assume the mud was 100% clay, though it did contain some silt.





I've put the mass in a bag for now to keep it moist so I can press in some mosaic tiles and give it further polishing. Though it's only a 20" wheel it is incredibly heavy, which is a good sign though it will be lighter when it dries out.
halifaxearthtech: photo by Lykaestria from Wikimedia Commons (Energy)
I found a sattelite dish last evening. It must have blown off someone's roof. At any rate it looked like it had been sitting outside in the parking lot a long time. This was an exciting find, because sattelite dishes are parabolic in shape, and are designed to focus radio signals from tv sattelites onto a reciever, which translates the signal into something a television can interpret.



A sattelite dish is a three-dimensional parabola, and it can also focus the sun's rays onto a point. These are already being made to function as stoves. There are already tons of blogs about this within a search of seconds.

This guy is enjoying melting My Little Ponies in a collector made from a very large dish, being used in California in high summer. This blog illustrates an interesting fact that dark objects will cook faster than lighter ones. Hence a marshmallow will take a long time until it starts to singe, and then as it gets darker will burn more and more quickly.

http://www.cockeyed.com/incredible/solardish/dish01.shtml

I became skeptical of the potential of a little collector in March in the far North but I had to try.
This kid made something he colourfully calls the Solar Death Ray: power of 5'000 suns. This sattelite dish is only slightly larger than mine.

http://www.youtube.com/watch?v=TtzRAjW6KO0

And Myth Busters also covered this in Archamedes Death Ray

http://www.youtube.com/watch?v=emX8KGc8xPo

This company is in Nova Scotia and uses two parabolic mirrors to melt small quantities of metals. They are looking for investors

www.lunenburgfoundry.com

So last night, instead of putting together a workshop I'm supposed to deliver today, I spent the night cleaning the grime off of the dish and fixing it to a base. I'm sure the attendees of a workshop on food forests will appreciate the importance of immediate gratification given this opportunity for passive solar technology.




This one has some nice adjustability


When the dish was immaculate, I glued on strips of aluminum foil. I'd already started this process by the time I learned that little mirrors would work better by creating a more highly reflective surface.



It must be said that concentrating the rays of the sun can set things on fire and blind you. If you think that a fusion reactor several tens of thousands of times the size of the earth doesn't have the potential to harm you if underestimated, I am not responsible for any repercussions.

Then I waited till the earth turned Halifax toward the sun again.
Today is a hazy day. The sun could be concentrated into an area the size of a tennis ball. When I placed my hand in the focus it became warm.

I also need to build a more robust food-holder. I've taped on the original plastic antenna to remember where the focus point is located.

This is a sun-finder, really a section of pvc pipe with two holes drilled 180 degrees apart. When you can see the sun shine through both holes, you know the sun-finder, and anything parallel to it, is pointed toward the sun. It is near the time of being equinox, and we are near the 45'th latitude, so the sun is about 45 degrees from the horizon at noon.



I think my next attempt will be with mirrors. I am finally becoming somewhat proficient with the glass cutting knife, or I might just purchase and dismantle a disco ball. Hopefully by summer I will be nearer my goal of bringing Halifax to its knees boiling water for coffee or tea.
halifaxearthtech: photo by Lykaestria from Wikimedia Commons (Energy)
The Maria Telkes cooker is finished and I've given it a trial run
This is a design I got here
It took me six attempts at the wooden main cooker box part, because I don't have great tools, and I am a beginning woodworker.




















The large foil fins are for focussing sunlight into the box over the range of time and sun-tracking for however long it takes to cook what you are cooking.
As a test I attempted to melt cheese onto toast. The cheese got warm, and vapour condensed into a fog inside of the glass, but it did not melt. Either February is too cold here to use it outside, or the box needs better insulation (there were gaps in the caulking), or or something else. I did make the box smaller to fit the panes of glass I had avaiable, because I just couldn't get the hang of the glass-cutter, but maybe the smaller box just won't get as hot. The box according to the plans was truly enormous. With the fins I'd say the box is still a bit too large and bulky to be practical and I'm interested in seeing how small I can make it.

Stay tuned!

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