Hot water is something that many people take for granted in the home. It is a basic necessity of life for most households. If the power goes down or a disaster strikes, then hot water will be one of the first things to go. This is why an ingenious engineer developed a simple do-it-yourself way to create large amounts of hot water with nothing but stove parts, wood, an old water heater and a thermosiphon. The method can heat up an entire hot water tank in anywhere from 30 to 45 minutes in an emergency.
The key part you need is a thermosiphon. This a length of copper tubing that has been coiled around on itself like a tightly wound spring. The siphon should be around 10 inches high and about four inches in diameter. Set up a small stove outside and attach four-inch stove piping to the top. Place the thermosiphon in the stovepipe over the heat source. You will have to cut holes in the sides of the pipe since the top and bottom ends of the thermosiphon need to be exposed. Connect the cold-water line on the hot water heater to the bottom of the thermosiphon. Attach the top of the thermosiphon to the top valve on the water heater. Make sure there is water in the heater.
All you have to do now is stoke up a fire in the stove. The heat will draw the cold water up from the bottom where it will exit the thermosiphon at the top and enter back into the water tank. This is slightly dangerous. The water will be far too hot to use when it comes out of the tank. Additionally, the water could become several hundred degrees in temperature and cause damage to the tank.