What size battery is needed to power the house?





Batteries Tesla i>

Tesla announces the development of the battery for home use. Cool. But why? Here are a couple of options:

- Self-contained house, solar or wind powered energy. These sources do not provide a constant supply of energy, which means that it must be stored somewhere
- Many homeowners keep at a diesel or gasoline generator. Used infrequently, but when you suddenly need - it is irreplaceable. You can instead use the generator battery
- Power company would like to have each had the battery. Then it was possible to reduce the peak load on the network. For example, when you turn on the air conditioner or other consumers.

But how big the battery should be to meet our needs?

How long should the battery be able to work? Musk said something about a week. Ok. Now - energy consumption. I will make the assumption - 2000 watts continuous consumption. Of course, sometimes need to, but sometimes less. On average, let it be 2 kW. If you are confused by this figure, you can easily substitute your.




Watt - a Joule per second, so it's time to recalculate seconds.




Now one can calculate the amount of energy stored in the battery.




To imagine how much energy in joules will conduct an experiment. Take a book and put it on the floor. Now lift up and put on the table. To raise the books you energy costs (increasing its potential energy in the gravitational field). Book weighing pounds, raised by 1 meter, receives energy of about 10 joules.

Let's go back to the batteries. The dimensions of the battery depends on its type. At Tesla - lithium-ion batteries. By Wikipedia , the energy density of a battery is 0.9 - 2.23 MJ / l (megajoules per liter). Suppose Tesla supply the best batteries in the world. Then cubic meter battery will contain 2.3 x 10 9 sup> Joules.

We denote the energy density as σ, and the volume as V:




We substitute the known values:



Get about half a cubic meter. Not Bad. The house in general can make it to the height of the ceilings, somewhere 2.5 meters. A beauty make the battery thickness of 10 cm. Then the width of it should be about 2 meters. Might work.

For fun here estimated that for the power house from batareek- "tablets" they need to be about 40 cubic meters. And you can count to warm themselves:

- How many AA batteries required for powering homes and what they will take the volume? We can assume that it holds about 10 kJ of energy .
- If you decide to feed your house from the nuclear station operating thorium, thorium as you would want? The energy density can be taken from Wikipedia
- Because Apple decided build solar power plant of 130 MW for internal use, it is possible to calculate what size panel you would be needed for powering your own home ? Imagine that the sun produces 1 kW of energy per square meter, and the efficiency of the panel is 25%. Do not forget that during the day the angle of incidence changes. In the calculations can be useful this post .

This is a translation of the article. As you know, the best way to learn something on the Internet - to lay out the wrong answer. In connection with this, on this occasion, I would love to hear the story of how you have done in your home power system, backup or offline. I>

Source: geektimes.ru/post/246048/

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