The only difference is in length, they both do the same thing.
Not if it was disconnected properly
This are used to convert solar energy to heat i.e thermal energy for using various purposes e.g solar cooker ,cncentrated solar power,solar water heater,solar furnace etc
Yes you can do that. I had an oil fired furnace that also heated the hot water in a coil inside the furnace. I got an electric hot water heater and had a plumber disconnect the coil in the furnace and hook up the electric hot water heater. No problems after four years.
by the way the steam condenses back to water
Stove Refrigerator Microwave Iron Curling Iron Blow dryer Furnace Hot water heater Toaster Coffee Pot
a heater a thermal jacket water and food
1 hour
Central heating systems usually heat on a different system from the hot water heater, unless the main heater is a combination furnace/hot water heater. If this is the case, it could be because the outflow of hot water is greater than the ability of the furnace to heat the water.
Is the furnace a hydroponic system? If it is you only need to get a heat exchanger (As you don't want the water to your heater flowing through the furnace) and plumb it as another zone in your house. If not you need to find a device for heating water that fits your furnace. and plumb the heat exchanger to that. I believe an heat exchanger is required by code in either case.
If your furnace is less then 50000btus then yes.
No, each must be vented seperately.
It doesn't. It comes from the water heater which is usually close to the furnace. In the basement or utility room.