What do you think about the idea of using a chest style of deep freezer for storing hot water?

[John Allen]

What do you think about the idea of using a chest style of deep freezer for storing hot water?

Even in working order they are pretty cheap used, and I suspect you can get paid for picking up one that no longer gets cold.

http://froogle.google.com/froogle?q=chest+deep+freezer&btnG=Search+Froogle

I'm particularly attracted to the air tight seal on the hinged lid. I figure I could add more rigid foam insulation on the outside, if needed.

20 cubic feet of storage would be enough for daily use. Of course about a cubic foot may be lost due to drilling holes in the sides - near the top, for pipes, unless one has complete confidence in sealing the pipes to the interior liner.

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John A Allen

[Tony Luck]

Interesting idea.  20 cubic feet ~= 150 us gallons ... a reasonable size.

I wonder what the "R" rating for the insulation in the freezer walls is. When being used as designed, they have a delta-t of about 70 degrees fahrenheit (say 70 degree house on the outside, 0 degree frozen food on the inside).  This is quite a bit less than you will be operating at (say 40 degrees outside air in your basement in the winter, and 160 degrees water on the inside). In addition, the freezer designers may make use of the fact that frozen food doesn't pack smoothly against the walls of the freezer (unless you have nothing but packs of frozen peas!) and there are no convection currents ... so they may skimp some on insulation.  So you may well need to add the extra layer of rigid foam that you mentioned.

You'd score lots of environmental points for recycling "dead" freezers that would otherwise be headed to the landfill :-)

You'd have to be sure that the freezer is watertight ... it ought to be, but if it wasn't, nobody would notice (well not while it was still working ... ice doesn't seep out through small holes). I've owned chest freezers that had a small drain outlet that was intended to empty the water out when defrosting ... they only had a cheap plastic pipe with a plug in the end for this purpose, which might not be adequate to hold when you filled the freezer with water.

Do modern chest freezers have "auto-defrost" cycles?  If so, they might also not be water tight by design.

-Tony

[John Allen]

Tony,

You raise many good points. Another one, is that this idea would not scale very well even if it passes some of the hurdles you mention since there is a very limited supply of used chest freezers. Easy come, easy go. I donate this idea to the DIY world. (Do It Yourself)

Here is my latest idea. I'm always looking for feedback so please, one and all, let me know what you think.

Sheet metal cylinder with no top or bottom moved into the site in a floppy collapsible condition, maybe even as a roll. This will allow a fairly large size to enter via a standard door. Set it up on site and spray the inside and bottom with insulating foam that would also form a waterproof layer. Then cut holes near the top for pipes. Add a rigid foam top and you are done. Glue the top down if you are very confident. and cut it off if needed.

 Toss in a sight tube or some other fluid level indicator. Maybe even a "window" but that would be a thermal bridge. Tonight I received a call back from a foam guy and he said his open cell would sort of work but he knew of two closed cell foams that would work even better. Size could easily start at 4x4 ~ 300 gallons and expand up to 10,000 gallons. This is basically an above ground swimming pool with as much insulation as you want. The foam guy said he would send me more details tomorrow via email.

ja

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John A Allen

[Tony Luck]

This one looks much better.  This one stands or falls on the properties and durability of the foam.

 

This is also a good area to explore.  I've been shocked at how much people are charging for commercially made hot water storage tanks. Surely there must be a good solution for this part that doesn't come with a four figure price tag.

 

-Tony

 

[John Allen]

tony,

Thanks for your input. That encourages me to climb the barrier I ran into today. The first three foams I looked at are apparently not suitable, but the vendor suggested that I give up on folks that do insulation and talk to folks that do Industrial coatings.

On a broader front, I've decided to toss my hat in the ring as a Solar Thermal integrator/installer. I'll try to accept better components as they become available, and continually refine the system designs to fit the customer and the current state of the art. I plan to be open for business no later than when the CA subsidy becomes available. this is currently projected to be July 2008.

I'm very interested in working with other people on this so let me know if you want to be more than casually involved. I plan to enter the CCTO competition this year. I'm also talking to another team about importing both components and systems from China. I intend to include a complete monitoring system at least as good as I now have. One reason for this is that there will be real time alerts to me for any failures. The last big detail is that I plan to give the customer the choice of buying the system or the BTUs. For those folks that do not want to pay the upfront capital cost, I'll be looking for green investors to contribute at least the hard cost.

Feedback?

ja

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John A Allen

[Tony Luck]

Keep the insulation folks in the back of your mind.  The end solution is possibly a multi-layer one:

• Outside: The metal cylinder - provides enough mechanical strength to hold everything inside (looks nice too)
  
• Middle: Layer of insulation - keeps the heat in
• Inside: Layer of ??? - Protects the insulation from getting wet.

This third layer needs to be:

• Watertight - for years ... at least 10-15
• Survive temperatures up to 190 degrees F (or even 212F if the control system doesn't cut out and lets the system start boiling water)
• Survive temperature swings (from 50 degrees to 190 at the extremes ... but usual day to day changes will be less)

Now maybe you might find something suitable that is also a good insulator, and cheap enough to put in a 2-3" thick layer ... but if you don't, then think of the multi-layer solution.

I don't think that I have the time to be more than casually involved ... but I'm happy to bounce ideas around here, or even in a face to face brainstorming session once in a while.  The CCTO looks like fun ... but too much fun and not enough time for me :-(

Perhaps I'll be ready to be a customer by July 2008.

-Tony

[John Allen]

Thanks Tony for your input. I'll work with it.

I'd love to have you for a customer someday. Meantime keep that day job and chime in when you can.

ja

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John A Allen

[Joe Rich]

John - I have been thinking of this for SLI. There happens to be one
discarded along the railroad tracks behind SLI and it looks enticing.
It comes with insulation, should be water tight, and should be
relatively inexpensive.

On Apr 17, 8:24 pm, "John Allen" <johnaal...@gmail.com> wrote:
> What do you think about the idea of using a chest style of deep freezer for
> storing hot water?
>
> Even in working order they are pretty cheap used, and I suspect you can get
> paid for picking up one that no longer gets cold.
>

> http://froogle.google.com/froogle?q=chest+deep+freezer&btnG=Search+Fr...

[John Allen]

Sounds like a good fit. I suspect hot showers are an important component of SLI. Anything I can do to help? What do they already have in the way of Solar Thermal? Are you in Hopland now?

ja

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John A Allen