Alternative Power sources - Phrugal phase change materials

Author

Phrugal phase change materials

nicksanspam@ece.villanova.edu

2007-05-19, 9:25 am

George Lane is 75 years old and used to work for Dow Chemical and has about
150 patents, including US 4,613,444, "Reversible phase change compositions..."
issued on 9/23/1986, now expired, which describes adding a dash of sodium
chloride and potassium chloride and about 2% strontium chloride hexahydrate
to calcium chloride hexahydrate to help ensure phase change stability, ie
lots of cycles, freezing at 26 C and melting at 30. A similar German product
(Doerken DeltaCool24 or 28) in thin plastic pouches costs about 5 Euros/kg,
plus shipping. George says don't heat his mix much above 40 C, because that
will melt the nucleation centers, which might not return until the mix is
brought to 0 F.

Here's a link to his 12-page patent:

http://geocities.com/davidmdelaney/...composition.pdf

George says the containers need to be strong to avoid being scratched or
punctured by the mechanical actions of freezing and thawing. There's a 10%
volume change with phase, so the containers must be elastic or pleated or
have some air fill to reduce the peak pressure. They want to be well-sealed
to avoid losing or gaining water from surrounding air, with plastic walls
at least 0.035 inches thick, but this can be avoided by keeping the air at
an RH of about 35%, with something like the vapor pressure of CaCl2+6H20
at 90 F (a humidistat might open a solenoid valve with a soaker hose inside
a small room with an air heater. We can't add too much sodium or potassium,
saturation is fine, but too much or too little strontium gives the freezing
curve a slope vs a plateau. George says 1-liter soda bottles could work well
in 90 F air at 35% RH, or less. We might look at the water level and top up
1000 bottles every 10 years.

George made calcium chloride hexahydrate from DowFlake and PellaDow road
salt, at about 5 cents a pound (the strontium salt used in road flares
costs twice as much), by adding salt to water (for safety, since this is
exothermic.) The salt starts as a di- or tetrahydrate with desirable
impurities. When I suggested baking it in an oven to drive off the water,
then adding water to double the weight, he said that couldn't be done
without disassociation, but a university chem lab could analyze the water
content by various simple means. I wonder how...

One application might be a house in Calgary, Alberta, where 751 Btu/ft^2
of sun falls on a south wall on an average 18 F December day. It needs
about 144K Btu for 5 cloudy days in a row.

If 1 liter stores 225 Btu, we might have 144K/225 = 640 1-liter bottles
(about 40 ft^3) in a horizontal hexagonal stack in a small room with
an air heater or a south window made from 2 layers of GE HP92W 10 mil
Lexan polycarbonate film enclosing a 7" waterproof glazing cavity filled
with tiny cold soap bubbles (US R20-30) at night and filled with air
during the day, when 600 Btu/ft^2 of sun might enter the room over 6 hours.

If the store recharges in 5 days at 28.8K Btu/day and the bottles have
565 ft^2 of surface with a 1.5 Btu/h-F-ft^2 airfilm conductance so
the room air is 86+28.8K/6h/1.5/565 = 92 F during charging, 600A
= 28.8K+6h(92-20)A/2 makes the window area A = 58.5 ft^2, so an 8'x8'
window might do. An 8'x12' window could also provide some warm air
for the house on an average day.

Know anyone who can turn George Lane's patent into a foolproof DIY
cookbook recipe? This might be sold in a 1-pound kit with enough
strontium salt to treat a 50 pound bag of local calcium chloride.

Nick

JeB

2007-05-19, 1:25 pm

On 19 May 2007 09:13:42 -0400, nicksanspam@ece.villanova.edu wrote:

>George Lane is 75 years old and used to work for Dow Chemical and has about
>150 patents, including US 4,613,444, "Reversible phase change compositions..."
>issued on 9/23/1986, now expired, which describes adding a dash of sodium
>chloride and potassium chloride and about 2% strontium chloride hexahydrate
>to calcium chloride hexahydrate to help ensure phase change stability, ie
>lots of cycles, freezing at 26 C and melting at 30. A similar German product
>(Doerken DeltaCool24 or 28) in thin plastic pouches costs about 5 Euros/kg,
>plus shipping. George says don't heat his mix much above 40 C, because that
>will melt the nucleation centers, which might not return until the mix is
>brought to 0 F.
>

Are any of these materials dangerously toxic?
(eg: strontium chloride hexahydrate)

nicksanspam@ece.villanova.edu

2007-05-19, 5:25 pm

JeB <no@spam.org> wrote:

[color=darkred]
>Are any of these materials dangerously toxic?
>(eg: strontium chloride hexahydrate)

Dunno. I doubt it.

Nick

David Williams

2007-05-19, 5:25 pm

-> Are any of these materials dangerously toxic?
-> (eg: strontium chloride hexahydrate)

Eating a lot of it wouldn't do you much good, but the kinds of amounts
you might accidentally absorb by handling it wouldn't do you any harm.

Unless it's Strontium-90, of course!

dow

Derek Broughton

2007-05-20, 1:25 pm

nicksanspam@ece.villanova.edu wrote:

> George Lane is 75 years old and used to work for Dow Chemical and has
> about 150 patents, including US 4,613,444, "Reversible phase change
> compositions..." issued on 9/23/1986, now expired, which describes adding
> a dash of sodium chloride and potassium chloride and about 2% strontium
> chloride hexahydrate to calcium chloride hexahydrate to help ensure phase
> change stability, ie lots of cycles, freezing at 26 C and melting at 30. A
> similar German product (Doerken DeltaCool24 or 28) in thin plastic pouches
> costs about 5 Euros/kg, plus shipping. George says don't heat his mix much
> above 40 C, because that will melt the nucleation centers, which might not
> return until the mix is brought to 0 F.

A professor at Dalhousie U in Halifax, NS, experimented with similar
phase-change storage systems in the 70s, and found he couldn't cope with
the corrosion problems. I've wondered if, with modern plastics and
ceramics, it might not be time to revisit the method.
--
derek

dances_with_barkadas@yahoo.com

2007-05-21, 9:25 am

> George Lane is 75 years old and used to work for Dow Chemical and has about
> 150 patents

i'll see your history-of-engineering, and raise you five bucks:

Here's Baltzar Von Platen with the first commercially successful
absorption-cycle refrigeration

www.freepatentsonline.com/1609334.pdf

And here he is again, 55 years and 11 months later

www.freepatentsonline.com/4354361.pdf

dances_with_barkadas@yahoo.com

2007-05-21, 9:25 am

Jeff

2007-05-21, 9:25 pm

nicksanspam@ece.villanova.edu wrote:
> George Lane is 75 years old and used to work for Dow Chemical and has about
> 150 patents, including US 4,613,444, "Reversible phase change compositions..."
> issued on 9/23/1986, now expired, which describes adding a dash of sodium
> chloride and potassium chloride and about 2% strontium chloride hexahydrate
> to calcium chloride hexahydrate to help ensure phase change stability, ie
> lots of cycles, freezing at 26 C and melting at 30. A similar German product
> (Doerken DeltaCool24 or 28) in thin plastic pouches costs about 5 Euros/kg,
> plus shipping. George says don't heat his mix much above 40 C, because that
> will melt the nucleation centers, which might not return until the mix is
> brought to 0 F.
>
> Here's a link to his 12-page patent:
>
> http://geocities.com/davidmdelaney/...composition.pdf
>
> George says the containers need to be strong to avoid being scratched or
> punctured by the mechanical actions of freezing and thawing. There's a 10%
> volume change with phase, so the containers must be elastic or pleated or
> have some air fill to reduce the peak pressure. They want to be well-sealed
> to avoid losing or gaining water from surrounding air, with plastic walls
> at least 0.035 inches thick, but this can be avoided by keeping the air at
> an RH of about 35%, with something like the vapor pressure of CaCl2+6H20
> at 90 F (a humidistat might open a solenoid valve with a soaker hose inside
> a small room with an air heater. We can't add too much sodium or potassium,
> saturation is fine, but too much or too little strontium gives the freezing
> curve a slope vs a plateau. George says 1-liter soda bottles could work well
> in 90 F air at 35% RH, or less. We might look at the water level and top up
> 1000 bottles every 10 years.
>
> George made calcium chloride hexahydrate from DowFlake and PellaDow road
> salt, at about 5 cents a pound (the strontium salt used in road flares
> costs twice as much), by adding salt to water (for safety, since this is
> exothermic.) The salt starts as a di- or tetrahydrate with desirable
> impurities. When I suggested baking it in an oven to drive off the water,
> then adding water to double the weight, he said that couldn't be done
> without disassociation, but a university chem lab could analyze the water
> content by various simple means. I wonder how...
>
> One application might be a house in Calgary, Alberta, where 751 Btu/ft^2
> of sun falls on a south wall on an average 18 F December day. It needs
> about 144K Btu for 5 cloudy days in a row.
>
> If 1 liter stores 225 Btu, we might have 144K/225 = 640 1-liter bottles
> (about 40 ft^3) in a horizontal hexagonal stack in a small room with
> an air heater or a south window made from 2 layers of GE HP92W 10 mil
> Lexan polycarbonate film enclosing a 7" waterproof glazing cavity filled
> with tiny cold soap bubbles (US R20-30) at night and filled with air
> during the day, when 600 Btu/ft^2 of sun might enter the room over 6 hours.
>
> If the store recharges in 5 days at 28.8K Btu/day and the bottles have
> 565 ft^2 of surface with a 1.5 Btu/h-F-ft^2 airfilm conductance so
> the room air is 86+28.8K/6h/1.5/565 = 92 F during charging, 600A
> = 28.8K+6h(92-20)A/2 makes the window area A = 58.5 ft^2, so an 8'x8'
> window might do. An 8'x12' window could also provide some warm air
> for the house on an average day.

A few notes.

First, I have some memory of talking with an artist that made
sculptures out of empty plastic pop bottles. He had a source for the
clean unused and it seems to me it was not much money. After all 640
bottles is not trifling. If anyone really wants a go with this I'll look
into it.

Second, 28K BTUs is not a lot of energy per day. Is it really worth
making a store for that?

Third, 40C upper storeage limit does not lend itself beyond storing
excess air heater BTUs. I can't help but think that a brine storeage
would have a wider range of temperatures and would probably be easier
to charge for about the same energy density.

With all that said, there is something about calcium chloride as a
cheap energy store. Now if I could only find it in the south in the
summer! Perhaps the Dowflake which is used for road construction (but is
rather low in purity) is the way to go.

Jeff
>
> Know anyone who can turn George Lane's patent into a foolproof DIY
> cookbook recipe? This might be sold in a 1-pound kit with enough
> strontium salt to treat a 50 pound bag of local calcium chloride.
>
> Nick
>

nicksanspam@ece.villanova.edu

2007-05-22, 3:25 am

Jeff <dont_bug_me@all.uk> wrote:

[color=darkred]
>... I have some memory of talking with an artist that made sculptures out
>of empty plastic pop bottles.

A thermal mass tower might have 3 broomsticks surrounding a vertical bottle,
with 6 more vertical bottles around it, but bottle walls leak water vapor,
so they need to be topped up every year or two. Thinwall 4" PVC pipes might
work better.

>He had a source for the clean unused and it seems to me it was not much
>money.

I got a 1000 2-liter bottle sample free from a 7-Up bottler,
about 4'x4'x8' tall on a lightweight shrink-wrapped pallet.

> Second, 28K BTUs is not a lot of energy per day. Is it really worth
>making a store for that?

Sure, if you want to stay warm when it's freezing outdoors :-)

> Third, 40C upper storeage limit does not lend itself beyond storing
>excess air heater BTUs.

Most of the storage happens from 20-30 C, which makes the air heater more
efficient, with lower temp air inside and less heat loss to the outdoors.

>I can't help but think that a brine storeage would have a wider range
>of temperatures and would probably be easier to charge for about
>the same energy density.

How would that work?

Nick

dances_with_barkadas@yahoo.com

2007-05-22, 3:25 am

> 28K BTUs is not a lot of energy per day. Is it really worth
> making a store for that?

if your daily heat requirement is 27K BTU's, then it's a lot. If
you need more, then scale up the project. Or insulate better.

> 40C upper storeage limit does not lend itself beyond storing
> excess air heater BTUs.

I'll bet my next paycheck, that if we actually measured the
temperature of the two fluids you use - warm air, and warm water -
the temperatures of both, IN PRACTICE - would be lower than 40 C. As
far as theoretical desires for 3-weeks worth of stored heat, Nick has
already presented strong evidence that your ACTUAL chances of having
more than 4-5 bad-weather days in a row, are statistically lower than
your chances of getting rear-ended the next time you stop at a red
light.

> I can't help but think that a brine storeage
> would have a wider range of temperatures and would probably be easier
> to charge for about the same energy density.

Easy enough that you can show me any homepower houses that actually
do it that way? Not plans, or articles, or usenet-postings - a real
building, please.

> calcium chloride as a
> cheap energy store. Now if I could only find it in the south in the
> summer

I bet you also can't find jet fuel at your local strip mall. Does
it mean that it's not easily arranged to be delivered to your door,
with less than two hours of Googling and some phone calls?

spamtrap@teamvavavoom.co.uk

2007-05-22, 9:25 am

On 22 May, 08:09, dances_with_barka...@yahoo.com wrote:

> As
> far as theoretical desires for 3-weeks worth of stored heat, Nick has
> already presented strong evidence that your ACTUAL chances of having
> more than 4-5 bad-weather days in a row, are statistically lower than
> your chances of getting rear-ended the next time you stop at a red
> light.

That must be location-dependant. In my part of the world, it happens
every winter. For example, from 1st to 15 December inclusive last year
my solar panels produced nothing at all, and total output for December
2006 was just 2% of the April 2007 output. So 3-weeks worth of storage
would be nice, and better than zero which I have now, but I could use
a lot more.

Neon John

2007-05-22, 1:25 pm

On 22 May 2007 03:46:51 -0700, spamtrap@teamvavavoom.co.uk wrote:

>On 22 May, 08:09, dances_with_barka...@yahoo.com wrote:
>
>
>That must be location-dependant. In my part of the world, it happens
>every winter. For example, from 1st to 15 December inclusive last year
>my solar panels produced nothing at all, and total output for December
>2006 was just 2% of the April 2007 output. So 3-weeks worth of storage
>would be nice, and better than zero which I have now, but I could use
>a lot more.

Same here. It is typical to go a week or more in Dec to Feb with no sun at all. No
precipitation, just overcast.

I had a solar water heater for several years. For three seasons it worked well but
in winter, one might as well dog down the valves and leave the collectors dry until
spring.

IMO, Nick relies FAR too much on that NREL data. It's probably OK in some places but
here in this region, the geography changes far too quickly. 18 miles from here are
square miles of flat open plains. Here in the mountains, it's 10:30AM and the sun
still isn't shining on my property. It'll make my place in another hour but it'll be
gone by 17:00.

John
---
John De Armond
See my website for my current email address
http://www.neon-john.com
Cleveland, Occupied TN
What do you call 4 Blondes in an Abrams? Air Tank.

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