Storing most of your energy in hot water?

[john j]

In my house, most of the energy needed is heating or cooling.
So why not do most of my energy storage in, say 5 or 10, tanks of 1000 litres of water. Properly insulated.
They could be in the basement or a room, where the wasted heat would benefit the house.
When you need heat from the storage you send water through the coil of tubing in the upper part of the tanks.
When you have heat to store you send hot water through the coil of tubing in the lower part of the tanks.

Same tanks might be of use storing cool water during summer...
Tanks could be divided by temp, so you have tanks at, say 30, 60 and so on, giving best use of your heat.

Is this crazy?
Cheers, john, Denmark

[DamonHD]

Such thermal stores definitely do exist, but they end up being bigger than you might imagine.

For example, for my small house I'd need 40+ tonnes of water to carry heat from summer to winter for space heating.

http://www.earth.org.uk/milk-tanker-thermal-store.html

Rgds

Damon

[john j]

You´re right, but I want the watertanks to be a supplement to my battery bank.Thought they could become a substitute for buying more batteries.
Also here in DK, we have a problem of the windmills here making more power than needed, during night times and other times.
So if we get close to free electricity, this could be interesting...

[john j]

Damon, this site of yours is really amazing. Great job!

I plan on using heat recovery ventilation in my house.
And considering the standard hotwater tanks that you can buy with just 50 mm of insulation, would it be worthwhile to put more insulation on such a tank?
Any idea of the effect of another 100 or even more, say 500 mms of insulation?
John

[DamonHD]

I worked out that it was much much better to greatly increase the volume of water and go with lots of cheaper insulation then (say) just the minimum possible volume of water with the best possible insulation (vacuum panels).

In fact, my not-even-worthy-of-the-back-of-an-envelope calculations, IIRC, suggested storing twice as much water and being content with a 50% energy loss.  Soaking up the energy in the summer to compensate using more solar thermal collectors would not have been a problem.

Rgds

Damon

[fabricator]

Don't even consider DC water heating with a turbine, AC is the only way to make actual hot water and it takes a LOT, repeat, a LOT of wind power to heat water, especially in volumes in the thousands of gallons.

[artv]

Hi all ,...not really sure if this applies but, convection is alot like induction not inductance,....heat a copper tube with hot water ,place six tubes around the central core ,the heat transfers to the outer six ,...can this same technique be applied to inductors???.......and do the six hold the equal amount of energy of the core,...or do the sum of the six equall , the core...........artv

[BigBreaker]

You can decrease the volume of water necessary by using a salt, often calcium chloride.  the salt will make a hydrate with the water that "freezes" and melts at a useful temperature.  The phase change stores the equivalent of many tens of Celsius degrees in sensible heat.

As mentioned above though, it's best to store heat that started out as heat, IE solar thermal, and store electricity that started out as electricity IE wind power.  Heating and cooling use VAST amounts of electricity.  If you really want heat from your turbine, an electrically driven ground or air source heat pump is more efficient.  Resistance heating is only ~30% as efficient as a heat pump.

[roosaw]

While this may appear to be a sensible solution you are going to be surprised at the amount of energy you lose.  There is NO way to stop heat flow.  There are things you can do to minimize it though.  One large tank is better (less surface area) than several smaller tanks, more insulation is better up to a point after which it actually promotes better cooling (I did not believe this at first but the engineering don't lie), lots and lots of low temp water is better than a little very hot water (T^4 losses!!!).  The idea of seasonally storage is, well, let's just say very aggressive.  I'd say very hard and costly.  Course if it is free……..

[Antero]

You can get warming energy with wind and there is a good solution for warming controller;

http://translate.google.fi/translate?sl=fi&tl=en&js=n&prev=_t&hl=fi&ie=UTF-8&layout=2&eotf=1&u=http%3A%2F%2Fwww.poikkis.net%2Findex.php%3Ftopic%3D5032.0&act=url

Antero