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Minor solar oven setback

Posted by admin on Nov 21st, 2008
Nov 21

A little over a week ago we had a few days of high winds, high temperatures, and lots of devastating fires. It seems that the people who live in the north and eastern hills of the valley are always being ravaged by wild fires. Being in the valley it is always a concern that we might be affected by the fires and have something happen to our home as well, but since our house has been standing since 1952 without (fire) incident then I feel relatively assured that we are safe. If we could only find a way to immune ourselves from earthquakes….

Unfortunately my solar oven suffered a bit of a set back due to the winds, but it should be fixable with some spare Plexi-Glass I have from a previous experiment. I should be able to use it as a replacement if I so choose to use the same window frame.

High winds and an unstable bike next to glass = not a good thing

High winds and an unstable bike next to glass = not a good thing

Solar oven project update

Posted by admin on Sep 29th, 2008
Sep 29

I started cutting out the frame of the new solar oven from scrap plywood laying around in the garage this past weekend. I have all of the sides cut out and ready for assembly, I just need to find my wood dowel pins to put the pieces together and I need to find a scrap piece of wood big enough for the bottom. I had to make the sides in two pieces because I didn’t have anything left that was big enough to make it solid. Here’s what I have so far:

The top of the sides are set at a 30 degree angle – I had read that is the optimal angle for solar panels somewhere. Once I locate my dowel pins and find a piece for the bottom then it should go together fairly quickly.

Here’s a picture of the one I built last summer. It’s got an old window I found in our garage from some previous owner, and it works pretty well. It’s lined with foil and the bricks in the bottom are to help keep the temperature a little more even. The test I did with it yesterday got it up to over 170 degrees. If it was built a little better and all the gaps and holes sealed up then I might be able to get it hot enough to boil water. I’ll be adding reflector flaps to the new one to ensure it will get more than hot enough for that. It currently sits on an old skateboard for portability, because with the bricks it’s quite heavy:

Motorcycle hypermiling, and solar oven part II

Posted by admin on Sep 19th, 2008
Sep 19

Since becoming a new motorcycle rider over the last two months I’ve had to put my hypermiling “research” on hold. I needed to fully focus my attention on what I was doing while riding because looking at the pavement pass by and thinking that if I make one little mistake…and the pavement up ahead could be permanently embedded in various parts of my body. Now that I’ve got over 800 miles under my belt on the bike I’m feeling much more comfortable and have actually started incorporating a few of the techniques I learned while hypermiling in the car. The hard part though, is that since it’s a manual transmission and I don’t always know what gear I’m in, it’s a bit dangerous to put it back into gear in certain situations (like turns, for example) so I don’t coast as much as I could otherwise.

This weekend I’m planning to find as much scrap wood around the house and rebuild my solar oven. My initial attempt turned out alright, and we cooked some beans in it one day (I think it took 6 hours tho), but it’s not sealed very well and should be made deeper and more efficient. So, as promissed in one of my early on posts, I’m going to rebuild it and document it for those who might want to attempt the same project.

Silly project, day two

Posted by admin on Apr 10th, 2008
Apr 10

I took the mini solar oven to work today and unfortunately found a problem right away. The way the building is situated, the mid-morning sun doesn’t start to hit the window I’m using until around 10:30am. As the sun crept into the box I started taking temperature measurements at semi-regular intervals. Here’s what I recorded, it’s a bit disappointing:

10:30 = 75
11:15 = 85
12:30 = 95 – start of full sun in the box
1:30 = 102
2:30 = 98 – moved to the western window which caused the drop in temp
3:15 = 105
4:30 = 109

As you can see, the highest it got was 109 degrees but I was really hoping for around 150. I attribute this mostly to a tint on the windows and a slight haze in the sky. It was a bright sunny day, but I’m guessing there was about a 10% haze.

I’m going to give it another try tomorrow. I’ve added a 15″x15″ reflector panel to the lid to amplify the amount of sun being collected (I’ll take pictures later this week). I know that the reflector will help considerably and the lack of having one on the prototype I built for the backyard last summer was part of the problem with it’s inability to go higher than about 200 degrees.

I’m going to bring home the mini solar oven this weekend and test it outside to see how much of a difference the windows at work make.

Check back tomorrow!

Silly project, just for fun

Posted by admin on Apr 10th, 2008
Apr 10

I was at work today, heating up my lunch (which I bring every day, thanks to my awesome wife) in the microwave when I got a moment of inspiration. To hopefully help this all make a bit more sense, let’s start with a little back history to explain the basis of the project you’re about to read about. Last summer I built a solar oven which worked…okay, I guess. We did cook a pot of beans in it one day so I guess it works well enough. I’ve been meaning to revamp it and have been thinking about that more and more lately, which is probably the reason for my lunchtime epiphany today.

My idea was to build a small solar oven to heat my lunch in. I sit in an office on the south west corner of the building so I get decent light in the window by the time I get to work. I spent some time tonight building my contraption and I must say, I think it turned out pretty well. It’s in prototype rough mode but I think it’s actually going to work. I used two old cardboard boxes, used tinfoil, duct tape (new, unfortunately), and a piece of plexi-glass I used for a water heating experiment last summer. It’s probably about one cubic foot of interior space. Here’s a picture –

mini solar oven for the office

I’m going to take it to work tomorrow and test it out. I’ll report on what I find tomorrow night.

If you’re so inclined, this would be a great project to do with kids. I just started with a small box, made sure it was deep enough for a container, the back of it was high enough to accomodate for a 30-45 degree angle, then just started putting it together. One note is that I did double layers of cardboard for insulation, otherwise it wouldn’t realize it’s full heat retention potential 🙂