Would you be interested in....

[szopen]

I want to bounce an idea around and see what you guys think.

I see from this site that almost everybody uses an esky on their boat for storage of beer, ice, food, fish and whatever else you keep in there.

Esky is just an insulated box where cooling is provided by ice melting inside.

One of the things I have been tinkering with a while ago is a simmilar size freezer (it was for a very different purpose but it might work quite well on a boat).

Basic setup would be a 100L freezer, CFC free cooling system, running on power from 12V battery.

As a freezer has a fair bit of power consumption relying only on the boat battery is not an option.
This problem would be solved by a set of solar panels and a battery charge controller. This would provide enough power to keep the battery charged.

From what I have tested this setup can keep the freezer working 24/7.

As a side benefit your boat battery would always be charged.

So a real freezer working at about -10 C, no need for ice, all your stuff nice and cold...

Would you be interested?

And how much would you pay?

All comments appreciated.

[FNQCairns]

Hi szopen, here is what I would like and what would go through my head if I was thinking of one.

What is the max amp draw.

What would be the maintenance amp draw half full and frozen at or better than -12deg with an outside 36 deg ambient temperature with 3 30 second openings per hour (this to me is real world usage).

What physical size would the solar cell be.

Would the cell be easy clean type?

I would also like it to be a poly esky.

A saltwater sealed engine compartment.

Might all be too hard?

I will be looking for something like the above later, dont think I will find it though!

Cheers fnq

[szopen]

fnq,

I have actually made some of these freezers before so I am sure it works.
Funny thing they were build in China but solar panels and charge controller were coming from Australia (cheaper).

They were drawing less than 3 amps with compressor running
(70% of the time but with inside temperature set at -18 C, and outside at + 32C)
More than 10 openings per hour.

At the compressor start up it would draw a bit more but for a very short time only.

Solar cells output was a tad over 5.5 amps, that provided enough current to charge the battery for overnight operation (with much less frequent opening).
Solar cells were about 1.5m^2.
I have used standard rigid alu frame cells, other types would work as well.

I don't think a poly body would work well.
Inside tank has to be steel (galvanized and powder coated) or aluminum.
As the heat is going out through skin condenser the outside will have to be metal as well.

Sealed engine compartment is no problem (skin condenser).

At the moment I am just toying with the idea to use such a thing on a boat, not really ready to manufacture or sell.

[rabbitohbill]

What refrigerant are you running & whats the refrigeration capacity of the system in kW?....I guess at around -20SST.
The capacity will make or break this thing...as will cost.
Whats the wall thickness & whats the insulating material?
What brand of compressor?

[szopen]

I have used R134a.
Compressor was a special marine type unit as one of the most important things about the whole thing is the ressistance of compressor to shocks.

It was also a 12V DC unit and that helps a lot with power consumption.

For the box I have used a standard tropical class 100L freezer box as I could get them for close to nothing from the freezer factory at the time.
Insulation was 60mm polyurethane.

As said before this has been working with inside temperature at -18 C so it will work even more efficiently with -12 C or so which is all that is needed for a boat.

So capacity is not an issue.

I know that cost is.
So I have asked how much would anybody pay?

[FNQCairns]

szopen, sounds good so far, not yet completly sure what I would be getting to put a price on it.

A couple more questions, how long would the warrenty be and how inclusive also how would it perform at 32deg and 97% humididty?.
Also because I have not checked around to find out as if I was buying are there any other units out there that this unit would be competing with for my dollar?
Would it keep ice as well as a top quality esky if I didn't need to run it for the trip? and finaly how much weight would I be adding to my boat in total.
Making you work for your answer huh!

cheers fnq

[szopen]

fnq,

No problem with the questions.

Lets say a one year warranty for parts and materials, 3 year warranty for corrosion.

Or another option is a 5 year full warranty where you pay a certain amount every year. (In this way the cost of extended warranty is not included in original purchase price).

Yes it would keep ice as good or better than an esky.

I want to add again that one of the important side benefits of such system installed is that it will keep your boat batteries charged, if you have a flat battery just stop the freezer (it will keep cold for quite a while) and the current will go to the batteries.

Of course in the daytime only

Yest there are other solar powered freezers available but I have not seen one adapted to boat use (shape, waterproofing etc.)

Regarding the weight I would say maybe 50 kg not including the battery.
But than no ice to carry around either.


Regarding the price.

I would say around 2000A$.

[PinHead]

R134A...you are in China aren't you ? R12..I could make a fortune if I could get my hands on about 200kgs of that..it is still made and used in China I believe.

[scuttlebutt]

I'm interested to know how much bulk does this add - compared to a standard 100 litre esky, and where does the bulk go? Is it on a side, or underneath? I have a 100 litre esky on my boat (centre console) though "walk around" space is limited.

Also, what are the options for mounting the solar cells? For instance, in my Centre console I don't know where I'd mount them, unless they came in segments that could be mounted vertically on the console walls, and I imagine that would affect efficiency.

If those issues could be addressed I think it would be something for the wishlist

cheers,

steve

[szopen]

PinHead,

I know what you are talking about

Yes it is available in China, cheap as well. Slowly being phased out though. They did sign Montreal protocol but still have a few years to go.

As to you getting your hands on it...

I have seen once a TV program about people smuggling the stuff through the US Mexico border. In small filling cans. Much better profits than smuggling drugs (bought for 2$ sold for 12$) and simply confiscated if caught, no risk at all.

Scuttlebut,

The exact shape is to be defined, best to think about it as a smaller version of the house freezer. Extra space when comparing with an esky would be the compressor compartment.
I had also thought about something different shapewise that is a a higher unit lets say WxLxH 55cmx55cmx100cm so you use much less floor space and have a top lid to be used as a "table", can't sit on it though.

Installation of solar panels can be done in a few ways. If you have a fixed top/roof they can be there (best place) and hard type panels can be used, if no roof/top than soft panels (flexible) can be installed on the bow in front of the windshield.

[FNQCairns]

Hi Szopen, sounds like it is all worked out, I paid almost $1500 years ago for a portable low amp freezer, they are much less now and your idea really does sound good, I think I would consider $2000 today for a system that worked like you say with no compromises.

Hope you get it up and running.

Cheers fnq