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Energy storage

Posted: Mar 14 2019 8:29am
by unklegrumpknee
It doesn't have to be a battery!!!!

Phase change material.
Better yet Bio PCM.
Look at phasechange.com

Using this system one can use off peak power for air conditioning at a time when the outside temperature is less getting more " Cold for the buck"
Virtually unlimited cycle life.
The company has installed data to back up their claims of a three year pay back.
And it doesn't have to be an either/ or situation.
A much smaller battery combined with the PCM system could eliminate peak use completely.

Re: Energy storage

Posted: Mar 14 2019 1:28pm
by billvon
unklegrumpknee wrote:
Mar 14 2019 8:29am
Using this system one can use off peak power for air conditioning at a time when the outside temperature is less getting more " Cold for the buck"
Google Ice Bear. It's on the market now.

Re: Energy storage

Posted: Mar 15 2019 12:42pm
by unklegrumpknee
Thanks Bill
What they offer is not new technology.
The use of ice has been practiced for a long time. That's where the term ton of air conditioning started. A ton of ice a day.
A very dense storage system.

But think, doesn't it make more sense to store the energy at a temp closest to it's use.
No additional moving parts.
Less Delta T for the AC unit.

Re: Energy storage

Posted: Mar 18 2019 2:10pm
by billvon
unklegrumpknee wrote:
Mar 15 2019 12:42pm
But think, doesn't it make more sense to store the energy at a temp closest to it's use.
Not for A/C systems. They need a more significant temperature difference for effective cooling.

But for things like refrigerators (maintaining one constant temperature, with one level of heat flow in and out) they are great.

Re: Energy storage

Posted: Mar 19 2019 3:56am
by Punx0r
The greater the temperature difference between your storage (thermal mass) and the useage temperature, the physically smaller/lighter your storge will be (but the requirement for effective insulation will increase).

It's why we store hot water above the temperature we want to use it with and then dilute it with cold water. Otherwise we'd need a bigger hot water cyclinder.

Secondly, melting ice is undergoing a phase change (solid to liquid) and absorbs a lot of heat energy. So ice at 0°C disproportionately a lot more potential cooling than water at 1°C.

Re: Energy storage

Posted: Apr 02 2019 7:35pm
by unklegrumpknee
B. Said Not for A/C systems. They need a more significant temperature difference for effective cooling.
It is not being used for cooling, it is used to store the cold. Like industrial freezer packs

The greater the temperature difference between your storage (thermal mass) and the useage temperature, the physically smaller/lighter your storge will be (but the requirement for effective insulation will increase)
That is for sensible heat storage. The PCM is latent heat. A large amount of energy at the melting point.
Just like your ice example.
Ice is a phase change material. A PCM.
They do cover a large amount of area. Makes transfer easier. They are placed in wall or ceiling so they don't take up any interior space.
Zero space requirements.

Re: Energy storage

Posted: Apr 02 2019 8:40pm
by billvon
unklegrumpknee wrote:
Apr 02 2019 7:35pm
B. Said Not for A/C systems. They need a more significant temperature difference for effective cooling.
It is not being used for cooling, it is used to store the cold. Like industrial freezer packs
Well, but that's a slightly different application. Freezer packs go from -5C to +20C, and keep the +20C area close to 0C. They are good at this since they absorb lots of heat at their phase change temperature (say, -2C.)

Lining the interior of a room with PCM will be more problematic. If you set it to 72F (via formulation changes) then you have to get the temperature significantly below 72F to crystallize the material. Then it will tend to maintain a surface temperature of 72F. But then you have to have a temperature significantly _above_ 72F to get good heat transfer.

Re: Energy storage

Posted: Apr 03 2019 5:52am
by unklegrumpknee
B. Said Not for A/C systems. They need a more significant temperature difference for effective cooling.
It is not being used for cooling, it is used to store the cold. Like industrial freezer packs

The greater the temperature difference between your storage (thermal mass) and the useage temperature, the physically smaller/lighter your storge will be (but the requirement for effective insulation will increase)
That is for sensible heat storage. The PCM is latent heat. A large amount of energy at the melting point.
Just like your ice example.
Ice is a phase change material. A PCM.
They do cover a large amount of area. Makes heat transfer easier. They are placed in wall or ceiling so they don't take up any interior space.
Zero space requirements.

Re: Energy storage

Posted: Apr 03 2019 7:11pm
by billvon
unklegrumpknee wrote:
Apr 03 2019 5:52am
B. Said Not for A/C systems. . . . They are placed in wall or ceiling so they don't take up any interior space. Zero space requirements.
If they are placed in walls and ceilings (presumably of inhabited space) but they are not used for A/C purposes - what are they for?

Re: Energy storage

Posted: Apr 03 2019 8:31pm
by amberwolf
The basic idea is something like "thermal mass" (without much mass), to keep the room within a narrower temperature range.

A while back before my housefire, I looked around at PCM wallboard, that does basiclaly this. Dunno how they work exactly, but that's how they were advertized.


(after the fire, didn't need it, they added an inch of foamboard insulation between the walls and the drywall, whcih has made a tremendous difference all by itself).

Re: Energy storage

Posted: Apr 03 2019 8:43pm
by unklegrumpknee
Exactly Amberwolf thermal mass. Constant temperature thermal mass. Which is even better.

Re: Energy storage

Posted: Apr 03 2019 8:55pm
by unklegrumpknee
The latent heat of water is 144 BTU/lb
1 degree F raise in temp requires 1 BTU
A lot of the PCM'S are about half.
So that one pound melting is equal in storage to 72 lbs of water changing one degree,

Re: Energy storage

Posted: Apr 14 2019 11:10am
by jhaz6471
If you were to build a new house 2k - 2.5k sq ft, Insulate it well , put up a double car garage and put a basement under it, and insulate it.
Fill it with water , there is enough heat value in it to heat your house the entire winter. Summer season there is enough ice for the summer for cooling in north east Ohio.

1) heat pump 2 for 1 energy value -buy one . get one free
2) No waste of energy of the season, hot or cold
3) heat pump does not operate in the summer

One giant ice cube :shock:

JimJr

Re: Energy storage

Posted: Jun 12 2020 11:08am
by unklegrumpknee
jhaz6471 wrote:
Apr 14 2019 11:10am
If you were to build a new house 2k - 2.5k sq ft, Insulate it well , put up a double car garage and put a basement under it, and insulate it.
Fill it with water , there is enough heat value in it to heat your house the entire winter. Summer season there is enough ice for the summer for cooling in north east Ohio.

1) heat pump 2 for 1 energy value -buy one . get one free
2) No waste of energy of the season, hot or cold
3) heat pump does not operate in the summer

One giant ice cube :shock:

JimJr
The challenges of doing that especially the large block of ice. The expansion would destroy the walls. The water being stagnant: how much algae and bacterial growth would there be?
Phase change material eliminates these challenges yet can be a tenth or less in size and still be very cost effective.

Re: Energy storage

Posted: Jun 13 2020 12:44am
by Hillhater
Here is a video etc od a house that you may find interesting..
Its known as the WaterTank house, in Adelaide SA.
It is a very unique design with some novel features, as well as a custom design.
It does most of the things you wish for..cool in summer, warm in winter, etc, but also conserves water in a very dry climate.
https://www.lifestyle.com.au/tv/grand-d ... ?id=367022

Re: Energy storage

Posted: Jul 07 2020 11:13am
by jhaz6471
unklegrumpknee

The challenges of doing that especially the large block of ice. The expansion would destroy the walls. The water being stagnant: how much algae and bacterial growth would there be?
Phase change material eliminates these challenges yet can be a tenth or less in size and still be very cost effective.

-------------------------------------------------------------------------------------------------------------------------------------------------------------------

1) Expansion problems -- Freeze from center of block to outside , expansion occurs at phase change - 10% All the expansion is
done before it gets to the walls.

2) Use reverse osmosis water -- Bacteria and algae need food to grow, No sunlight , not much grows at a max of 55F.
Well water would be a problem if it did . Most of the time the temp will be 32F solid or liquid

3)a) Water doesn't have the corrosion problems of an other phase change materials have. Once the water losses all its free oxygen ,
It will not corrode any thing more. I have have 90 year old steel boiler pipes that look almost new on the inside of them along
with the cast iron radiators to attest to that.

b) Cost - water is cheap compared to the others

c) Water phase change is 144 Btu's per pound 32F liquid to 32F solid and is closer to the average temperature outside of the house
for heat losses or gains in this my part of the country (USA).
d) Other than the cost of the insulated room under the garage , the heat pump would be equal to most heating or air conditioning
systems costs. Almost no maintaining costs . A closed loop system.
e) water is 25 times more efficient than air in transferring Btu's

f) No EPA hazards ,No steam problems , Low heat differentials . Lowest possible temperature over shoots in the process. Least
amount of electricity and outside of the house equipment . Heat coefficient is better than at air at 10f degrees


Jim Jr