I want to raise Australian Red claw crayfish and I been thinking (a dangerous thing). So how about this for heating the water? Set the tanks up in a greenhouse and use it to heat the water during the day and then get a marine battery, a trickle charge solar panel, a 12 volt water heater element, a timer, and a thermostat. Use the sun to charge the battery during the day, set the timer to heat the water at night, and use the thermostat to control the water temperature. You could use a water heater thermostat and use the lowest setting (90 degrees f). You may have to do a little adjustments to the thermostat but it may just work. You could also heat a greenhouse at night with it. The water tanks could be built out of just about anything. I am thinking about plywood and masonry waterproof or epoxy paint. Anyone else have some simple solar solutions??? Anything would be welcome!
When you run the numbers, you will discover that getting your power from the grid will be much cheaper than the PV-plus-battery alternative, unless you live in a place without a grid connection.
I ran the numbers for a small windmill to hot water heater setup. No grid connection, just the windmill powering a second heating element in the water heater. Buffered through a car battery, since a big wind gust could make enough voltage to pop the heating element. It was something like a 20 year payback. Not counting labor time, and assuming nothing broke. Not a good investment. Ranchers do use such setups out in the field to keep water troughs from freezing, but like PD said, a lot of this small-scale stuff is only sensible in off-the-grid locations.
In a greenhouse you probably wouldn't need a separate heat source to heat the water if you insulated the ground under the water container to keep the ground from sucking up the heat. I have read solar greenhouse books that use water to heat greenhouses as far north as Wisconsin. I can get a battery trickle charger pretty cheap at Harbor Freight and a marine battery almost anywhere. Just off the top of my head....100.00 dollars for the charger (solar), 100.00 for the battery, and I am not sure about the twelve volt heating element and thermostat. I would also need fittings to house the element and a little wiring. Having said that I am going to go with an electric line considering I have power up there anyway. Heck,it was in the seventies today and my low point on the water is about 60 degrees f. I also don't have the money to buy much at all. With my existing power i could set the thing up for a little over 25 bucks.
About 70.00 dollars for water heater element and thermostat...12 volt - - - Updated - - - Did you put a fuse in to keep the element from popping?
agreed, I use solar for some lights around the yard and for camping, but not for much else, mainly due to cost.... but the tech keeps getting cheaper..... and better solar works best attached to the north or south side of the house for lights .
Solar cooker heats up super fast... South African Company Designs Unique Solar Cooker April 30, 2016 Two-man team of solar power technologists introduces Sol4, hot plate that heats up so fast its like cooking with gas or electricity