Author Topic: 500 gallon battery  (Read 5272 times)

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vawtman

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500 gallon battery
« on: November 15, 2007, 01:22:53 AM »
A thought ive been pondering.

The water from the well comes in at say 50deg.and feeds a water heater that needs to heat it to what we like probably at least 50 more degrees.


 If wind/solar and basement heat could raise this there wouldnt be many losses.


 If the turbine raised the tank to say 90deg in winter it would be radiated out to the house.


 Put elements in the tank and it would be hard for any turbine to overheat the water to any high limit region.

 During the summer it could be insulated for normal hot water.


 Thoughts

« Last Edit: November 15, 2007, 01:22:53 AM by (unknown) »

elvin1949

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Re: 500 gallon battery
« Reply #1 on: November 14, 2007, 11:06:25 PM »
vawtman

 I am setting up a small greenhouse [8ft by 20ft].

Plan on using a solar heated 350 gallon tank for

heat storage.

 Will see what happen,s.

later

Elvin
« Last Edit: November 14, 2007, 11:06:25 PM by elvin1949 »

Capt Slog

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Re: 500 gallon battery
« Reply #2 on: November 15, 2007, 04:44:08 AM »
Sounds reasonable, wish I had one!


Have you seen the sodium acetate solution method of storing heat?  I did a quick google search of the board but couldn't find it on here.  I saw a system using this on TV years ago.  Basically it's a huge version of those snap heat-packs, the ones where you have a gel and when it crystalizes it gives up it's latent heat.  The tank(s) are filled with this stuff and you liquify it during the summer when the heat is plentyful, when you need the heat in winter you set it to crytalize and get the heat back.  I remember seeing what loked like channels of the stuff, perhaps 12-18 inches square section, running under the house.  I wondered at the time how it was controlled.


I've never seen it since, but a google search of the web threw up this


http://www.freepatentsonline.com/4603004.html

« Last Edit: November 15, 2007, 04:44:08 AM by Capt Slog »

scorman

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Re: 500 gallon battery
« Reply #3 on: November 15, 2007, 06:49:23 AM »
storing is nice, but need a complete system


did a quick check on the chemistry and note that the "melting point" of sodium acetate is 130F ..it has a high latent heat of fusion, which means that it is a good heat storage mechanism and most of all ...cheap ...but how do you make it work???


BTW, another trick is to thicken solution with starch:

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V1Y-48S4JCG-3&_user=10&_cover
Date=09%2F30%2F2003&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C0000502
21&_version=1&_urlVersion=0&_userid=10&md5=6f882a3945aa225216609e92e77db1df


These storage devices are typically used to absorb solar heat such as in a sunroom with large thermopane glass picture windows....but from my own installation, it is rare to get much above 100F in winter, so it wouldn't work there ..won't melt ..need a lower temp phase change chemistry


Other applications solar collector heating mechanisms inlude using high tech schott vacuum solar collector get up to 400C :

http://www.us.schott.com/solarthermal/english/products/receiver/details.html

I have seen this system in a residential offgrid in Ontario.

They pump thru heated tubes imbedded in concrete floors on both first and second levels.

BUT, why use phase change storage instead of simply using the house mass as a heat sink as above????


slightly OT - here is a potential use of heat used for cooling:

http://www.climatewell.com/


note that travel trailer 12v/propane fridge just uses heat to make cold ...no compressor


I too would like to have a use for any surplus wind energy in summer, once domestic hot water is achieved.


Stew Corman from sunny Endicott

« Last Edit: November 15, 2007, 06:49:23 AM by scorman »

ghurd

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Re: 500 gallon battery
« Reply #4 on: November 15, 2007, 07:06:19 AM »
I believe you are talking about a "tempering tank", that happens to have a dump load heater connected.

The local electric companies give a discount if the water heater is electric, and an 80 gallon tempering tank is installed.

G-

« Last Edit: November 15, 2007, 07:06:19 AM by ghurd »
www.ghurd.info<<<-----Information on my Controller

Capt Slog

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Re: 500 gallon battery
« Reply #5 on: November 15, 2007, 08:07:50 AM »
I went to the science direct site, an interesting article that along with your intial comments, has me puzzling.


The application of sodium acetate that I thought I knew, is that of a solution.  I used to make it for lecture demos when I was a university chemistry technician.  It's a long time ago, but I think it was around 50% vol/vol with water.  I used to boil it, and then put it to cool.  All this had to be done in very clean glassware.  Dropping a 'seed' of solid NaAc into the beaker would cause the 'supercooled' solution to instantaneously crystalize to solid, at which point it would give out loads of heat.  (actually, the favourite use was a conjuring trick; pour the liquid into a paper bag containing the seed, and then scrunch the bag up, it looks like the liquid has vanished!).


Now I'm not so sure.


The uses I've found today in various articles are using the NaAC not as a solution, but seemingly 'pure' stuff that is melted. I'm wondering now if I was mistaken all these years, and that in making my 'solutions' I was actually making the trihydrate form.


Either way, as you say, it needs a lot of heat to get it back to liquid.

« Last Edit: November 15, 2007, 08:07:50 AM by Capt Slog »

fcfcfc

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Re: 500 gallon battery
« Reply #6 on: November 15, 2007, 06:37:35 PM »
You don't want to use renewable electric for a heating application, IE PV, Wind, etc... Use renewable electric for non heating applications and solar thermal collectors for heating applications. Much more efficient and cost effective. If the old fuel tank is steel, it will rust out in time. You need a material that won't corrode. Using phase change materials is more complicated than you think. Better to stick with a properly sized pure water storage tank.
« Last Edit: November 15, 2007, 06:37:35 PM by fcfcfc »

vawtman

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Re: 500 gallon battery
« Reply #7 on: November 16, 2007, 04:28:19 PM »
Hi Bill

 I think different from you on this.Where you from?


...Mark

« Last Edit: November 16, 2007, 04:28:19 PM by vawtman »

feral air

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Re: 500 gallon battery
« Reply #8 on: November 16, 2007, 11:18:08 PM »
I think different too.


The MythBusters proved that an 80gallon hot water tank makes for a good projectile so watch out for that, whatever you do. You really don't want a 500 gallon tank poking out of your roof, or worse. ;-)


take it easy

« Last Edit: November 16, 2007, 11:18:08 PM by feral air »

JW

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Re: 500 gallon battery
« Reply #9 on: November 17, 2007, 12:57:53 AM »
I saw something simular, to the idea of a 500gallon thermal storage battery, in a popular mechanics issue a coupla years back. This used a heat exchanger tied into a lake on one side of a heatpump. Sounds like it would work. Heat loss would be in your favor. A heatsink of that size, could easily gleen some efficiency losses, which would be considered average mean temp, to desired heating or cooling conditions of the system your working with, vawtman.


 JW

« Last Edit: November 17, 2007, 12:57:53 AM by JW »

JW

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Re: 500 gallon battery
« Reply #10 on: November 17, 2007, 01:31:29 AM »
  Actually this idea could possibly work quite well.


 Think about it, if the 500 gallon tank was filled with brine(saltwater) And had 2 heatexchangers, one for the heatpump, and one for a air-to-water heat exchanger such as a 4core auto radiator(or 2 in series) outside the house. Done just right, the radiators outside, could use air convection instead of a fan to cool.


  The circulating pump could be a simple cyntrifugal type re-circulating the brine.


 In the winter you would cool the 500 gallon tank in the basment with the heatpump, and leave the circulating pump to the outside radiators off.


   My only concern is dew forming under the floor of the basment and the 1st floor.


JW

« Last Edit: November 17, 2007, 01:31:29 AM by JW »

vawtman

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Re: 500 gallon battery
« Reply #11 on: November 17, 2007, 06:25:40 AM »
lol :>(
« Last Edit: November 17, 2007, 06:25:40 AM by vawtman »

fcfcfc

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Re: 500 gallon battery
« Reply #12 on: November 17, 2007, 06:39:13 AM »
Central PA...

www.WeAreSolar.com
« Last Edit: November 17, 2007, 06:39:13 AM by fcfcfc »

fcfcfc

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Re: 500 gallon battery
« Reply #13 on: November 17, 2007, 07:11:47 AM »
Hi: Reading your first email again, it sounds like you want SDHW and maybe some space heating in the Winter. To be more specific on my comment below about RE electric for non thermal applications, unless you live on top of a high mountain and have wind turbines up the wazoo, (huge surplus of electric) you are better off using solar for heating. Not knowing where you live of course could change that, like if you lived in a "lake effect" zone with no sun basically. But aside form that, for heating, you want to size the storage tank with the gross area of the thermal array balanced against the average load. One of the easiest things to do is do a solar vertical air heater for heating months (given open wall space) at about 1 square foot of collector per 10 sqft of heated floor space. Put in a separate 80 gallon preheat water tank and a couple of evacuated tube collectors for a preheat system for DHW. This will give you 90+% of your DHW from the sun and take anywhere from 1/4 to 1/3 of you space heating load depending on many different variables. Sizing the vertical like that should negate the need to store the heat. You simply use it when you have it. The internal mass of the house will handle most overheat situations within a tolerance range The big cost savings here is that no storage is needed for the Winter system and no infrastructure costs trying to link the space heating with the DHW. These factors will keep you front end costs down..
« Last Edit: November 17, 2007, 07:11:47 AM by fcfcfc »

vawtman

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Re: 500 gallon battery
« Reply #14 on: November 17, 2007, 08:09:11 AM »
Hi Bill

 Im in Wi and am getting lake effect snow has we speak.Solar for me is pretty much out of the question 6 months out of the year.I do get great wind during that time though.

 To use a wind turbine to run the washing machine,well pump,dryer,stove ect.Would probably cost 5grand for the system.Payback would take my lifetime.


 Heating is probably 80% of my costs during this time of year.

« Last Edit: November 17, 2007, 08:09:11 AM by vawtman »

feral air

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Re: 500 gallon battery
« Reply #15 on: November 17, 2007, 01:07:59 PM »
"unless you live on top of a high mountain and have wind turbines up the wazoo, (huge surplus of electric) you are better off using solar for heating. Not knowing where you live of course could change that, like if you lived in a "lake effect" zone with no sun basically."


Or if you live in a "mountain effect" zone where there's cloud cover all day, every day, during the winter months.  :-(

« Last Edit: November 17, 2007, 01:07:59 PM by feral air »

fcfcfc

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Re: 500 gallon battery
« Reply #16 on: November 18, 2007, 04:37:19 PM »
Hi: Single wall evac's might work for you though they are a bit more expensive than the double wall design. They can gather a bit more usable heat on a cloudy day.

Electric wise, 3413 BTU's per 1KWH, so for even 100,000 BTU's of heat in a day you would need 30KWH, which would require quite a big turbine unless you had constant wind...

Your best bet might be a high efficiency Geothermal heat pump for your heating needs if you can afford the up front costs..
« Last Edit: November 18, 2007, 04:37:19 PM by fcfcfc »

vawtman

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Re: 500 gallon battery
« Reply #17 on: November 18, 2007, 05:35:48 PM »
Bill,Please remember one thing.Im doing this for a fun hobby.


 Thanks for all your thoughts though.


 I still didnt get the satellite dish converted yet.That i think will make an awesome solar collector.

« Last Edit: November 18, 2007, 05:35:48 PM by vawtman »

fcfcfc

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Re: 500 gallon battery
« Reply #18 on: November 19, 2007, 03:13:08 PM »
Direct beam energy only... I have one I use for high temperature solar demos at RE fairs and schools...
« Last Edit: November 19, 2007, 03:13:08 PM by fcfcfc »

vawtman

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Re: 500 gallon battery
« Reply #19 on: November 19, 2007, 04:21:36 PM »
Just visited your site Bill.Awesome work your doing.However didnt see a pick of the unit you descibe.

 Would be hot to see a pick and story about it.
« Last Edit: November 19, 2007, 04:21:36 PM by vawtman »

feral air

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Re: 500 gallon battery
« Reply #20 on: November 19, 2007, 05:04:39 PM »
"Electric wise, 3413 BTU's per 1KWH, so for even 100,000 BTU's of heat in a day you would need 30KWH, which would require quite a big turbine unless you had constant wind..."


To add another person (heat-wise) to your home you'd need to make about 3KWhs a day*.


That's an easier way to look at it for me since I know that 6 people wandering around my house is enough to keep it warm - 8 people if we're just chillin' on the couch or whatever. So my place takes roughly 18KWh a day to heat in the winter...not too bad.


How many people does it take to keep your place warm?...Minus the number living in the house=how many people you need to add, times 3=number of KWhs you need per day.


*An "average male" puts off about 390 BTUs an hour which is about 9360 BTUs a day. 3KWh is 879 BTUs more than that, so I've erred on the high side. take it easy

« Last Edit: November 19, 2007, 05:04:39 PM by feral air »

fcfcfc

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Re: 500 gallon battery
« Reply #21 on: November 19, 2007, 07:27:03 PM »
I only have 3 sections of the 8 done. It's a 3-1/2 meter dish. I just don't have the time to finish it. I manually just position the sections when I want to use it. I have a whole support structure complete with linear drives etc. for easy whole dish movement designed, but it is not done. Actually I am going to only do 7 of the 8 sections so I have a place to walk into to get close to the focus. I have so many incomplete inventions and projects, the stress load has taken all the fun out of it.. Such goes the need for money ... thanks for the site visit...
« Last Edit: November 19, 2007, 07:27:03 PM by fcfcfc »

sbotsford

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Re: 500 gallon battery
« Reply #22 on: January 10, 2008, 11:07:35 PM »
But the tank was built for oil.  Filling it with water will rust the tank fairly quickly. If you do this, you need to put an anti-corrosion additive into the tank water, and extract any heat from it for domestic use with a heat exchanger.


This would not be unreasonable to do:  Set up your heating elements.  

Put opening in top of tank, and run 100 feet of soft copper pipe, or 300 feet of pex tubing into the tank, keeping both ends outside.  This becomes the supply line for your domestic hot water tank.  When the tank is warm, it preheats your water.  When the tank is hot, your hot water heater doesn't come on.  when the tank is cold, you're no worse off than you were before.  Don't let pipe contact heating elements.


Need some fail safe:  If the element burns out, you could have a run-away windmill.

Multiple elements.  Continuity lights.


Not sure I'd want to take a chance with 500 gallons of hot water running around loose in my basement.  Had the relief valve pop on my water heater once.  That was mess enough.

« Last Edit: January 10, 2008, 11:07:35 PM by sbotsford »

sbotsford

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Re: 500 gallon battery
« Reply #23 on: January 10, 2008, 11:10:31 PM »
Keep reading.  There are problems with it going back into solution.  Sort of like the sedimentation problem in batteries.  


I've also heard about systems that use hydroscopic salts. When you let them absorb water vapour, they heat up, when you heat them up, they dry out.  Seems tricky to do, and also keep your house at comfortable humidity levels.

« Last Edit: January 10, 2008, 11:10:31 PM by sbotsford »

vawtman

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Re: 500 gallon battery
« Reply #24 on: January 25, 2008, 08:12:48 PM »
Hi sbotsford, sorry i missed your reply.

 I run commercial hot water systems that use air separators and rust isnt a problem even with no additives.All steel piping.

 Has far has the mill running away its early yet.To darn cold for anything lately.


 It is amazing how much the pressure increases when first heating a closed system.


 So the importance of an operating relief valve.


 Thanks if your around yet.

« Last Edit: January 25, 2008, 08:12:48 PM by vawtman »

finnsawyer

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Re: 500 gallon battery
« Reply #25 on: January 26, 2008, 08:56:01 AM »
Do you know how a sauna stove heats the water in the attached open top tank?  It's a gravity situation.  Cold water sinks and displaces the hot water.  A pipe directs the cold water into the stove where the heating occurs.  The hot water then flows out to the top of the tank.  You could do the same with a heating element wrapped around an external pipe.  For anybody that might be interested I've got a used 80 gallon glass lined water tank they can have for free.  They only need come get it.
« Last Edit: January 26, 2008, 08:56:01 AM by finnsawyer »