Solar Drying Oven

No matter the question, if you’re working on terrestrial community ecology, eventually you have to clip mountains of vegetation to dry and weigh. In the states that’s a relatively straightforward process of sticking vegetation in massive drying ovens until all the water is removed and you can get comparable dry weights. Here, the task is quite a bit harder.

Several friends here working in Naxos for the summer have been accumulating vegetation that badly needs drying, so we set out to figure out a way to make it happen. Our first hope was to put the vegetation, wrapped in mesh, out on our back veranda where it could slowly bake in the hot Naxian sun. It works great for our laundry, but our efforts with the vegetation were foiled by the neighbor’s pesky cats who took to laying on the little pillows of dry grass. When the cats started peeing on the vegetation, we knew we definitely needed a new method.

In Kenya, where I conducted my MS research, the Research Centre had a solar drying oven for researchers to use exactly for this purpose. I then remembered I even knew a solar drying oven expert; a part of Claire’s MS project was designing and building a solar oven for the rural village she was working with in Madagascar! I decided to try my hand at designing and building one for our use. Time was of the essence though, so you’ll have to excuse the shoddy craftsmanship.

First step was designing and then finding materials. Luckily, the design isn’t too complicated. Basically, you need a large, shallow box, covered with clear glass (or plastic?) for the sun to hit, warming the air and causing it to move up into a chimney shaped box where the vegetation is sitting. The continuous flow of warm air through the chimney pulls moisture out of the samples and leaves them dry in a matter of hours… in theory.

Materials were much harder to source, especially on a budget. Living on an island, everything needs to be imported by boat, so the markup on things like wood is exceptionally high. Finally, with Johannes’ help, we found a fellow with a lumber shop willing to sell us some wood for the project. He even offered to cut it for us if we gave him the dimensions. Unfortunately, Johannes then had to leave, so the next day it was up to me to communicate with him (he spoke very nearly no english) the dimensions and plans. To do so, I built this:

ImageThe top even opened! After a good laugh at my model, he happily took it into the back and started chopping away. It worked! I came away with the wood, ready to go.

Assembly was actually fairly easy and only took a morning. The wood was of such exceptionally low quality though that we had to pepper it with nails and screws to keep it together. In an effort to save on expenses we decided to use clear sheets of plastic for the warming bed instead of glass. The plastic is very similar to that on my father’s hoop house – seemed like it should work!

Image

And it did! For about 6 minutes…

As soon as I went back into the house, those pesky cats came to explore and jumped right onto the plastic, ripping it out of the nails. We tried sealing it with duck tape (as you can see above) but nothing would work, the cats were insufferably curious and whenever it was unattended would claw their way all over it, even climbing inside.

At this point we began looking for recipes that called for cat meat, but because we love our neighbor (if not her cats) we decided it was the plastic that was going to have to go. After a bit of hunting around, we found a pane of safety glass that might keep the cats at bay and get our vegetation drying. After a bit of finagling we finally explained to the glass shop owner just what needed to happen and he happily, albeit somewhat confusedly, cut the sheet of glass and drilled holes for us. I’m not sure I ever quite convinced him what we were doing with it.

So here it is! We had to fashion “washers” our of folded cardboard after the holes and screws ended up not matching, but it seems to be working and is 100% cat proof! (so far…)

Image

Advertisements

3 thoughts on “Solar Drying Oven

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s