Sunday, February 22, 2009

Solar Water Heater Project- Step One

I'm posting this on the web as a way to encourage myself to do some thinking before I get too far into this project. We'll see if I get past the thinking stage.

A couple of years ago I built a 12' x24' metal shed for the purpose of drying wood. It has a 10/12 pitched roof which is covered with clear "pro-sky" skylight material. The shed gets hot during the day but cools rapidly at night. It retains very little heat in the winter. There is a lot of solar energy going into the shed but the siding is uninsulated metal. The heat is dissipated very quickly.

From shed

I plan to turn the shed into a regular storage shed now which requires covering the skylights to make the space useful. I'd rather not waste the solar potential of this building.

The construction of the roof is 2 x 6 inch rafters 24 inches on center. I would like to use the space between each rafter as a solar water heater. I found a plan for a solar water heater on the Internet at :

The plan appears to come from the Maine Solar Energy Association( I think it can be adapted to my use.

From shed

To use this building as a storage shed and solar water heater I'm going to have to move it. The first task will be to get the stuff that has accumulated out of it. And figure out the best way to move it half a mile across the fields.

Questions I have currently include:

1. Can a system like this produce hot water in a Minnesota winter?

2. Can the pro-sky roofing material withstand enough heat?

3. Does the pro-sky material allow enough solar energy through to heat water?

4. The plan has 1/2 inch copper pipes spaced six inches apart. Heat transfer plates available for in floor heat applications, which I'm planning to paint black and use as heat collectors are only four inches wide per pipe. Will it affect the function of the heater much if I place the pipes 4 inches apart instead of six?

5. The design of my building does not allow for space to fill the system using gravity - what is the best way to allow for pumping water into the system?

6. What's the best way to move this shed?

Sunday, February 01, 2009

A Conversation with the Breeze

I had a conversation with a breeze. We spoke in the woods at the edge of a field. It was warm for winter. Snow stuck in clumps on my snowshoes. I had stopped, unzipped my coat to let the heat escape. I stood a moment in silence. Then it was two, then three.

There was an old apple tree in the bramble where woods meet the field, apples high up withered and clinging in defiance of winter. I stood and considered the trees, the apples and the snow. That is when it came. The gentle scrape of branches. The creak of old limbs and the rattle of leaves.

"I know you", I said to the wind as it carried away some of my extra heat. "You are the one who took my warmth last week. You helped the cold nip my toes". "No", it said. "I am not that old. I was just born there in the valley where the brown grass soaks up the sun. I made my way up the hill through these branches just now. I am headed for the field. Who knows what will happen then."

I knew it was true, I could smell brown grass from the valley. And then I was alone again.