Coleman Stirling Power Coolers

[thezfunk]

Originally Posted by GordMay

WELCOME aboard, and thanks for the information, thezfunk.

Your name intrigues me. Are The Z Funk, the ZF unk(le) or what?

Funny you ask. It was suppose to be Z Funk but way, way, way back at the start of the internet that name had already been taken so I tried 'the z funk' and it worked. I have been using it ever since.

[ericb]

Hi all. I'm new to this forum. I'm actually not a boatee, though.
I do know that the Coleman website states that the Stirling Power Cooler is no longer available. a real pity since i went thru a lot of trouble getting one...
However, Global Cooling is still selling the TwinBird version.
I'm in the Netherlands, and I ordered one last week from the Dutch office. I'm planning on hooking it up to a solar powered battery (18Wp Sunsei panel, 15Ah battery). I'm thinking that should be enough to keep the cooler running for some time...

Does anyone else have experience on using solar power for the stirling cooler? (I'm aware of the henhouse, but I'm trying to find the minimalist solution)

Regards, Eric.

[witzgall]

Eircb;

If you are considering a 18w 12v panel, and a 15ah battery, I would think that your power system would be very undesized for powering the cooler. I am not sure how much research you have done with respect to selar and battery systems, but 18w for perhaps 5 hours (I would guess less in the Neatherlands) would provide very little actual power to your battery, not enough to run the coller in any case, for that long.

I would also think that you would be draining the battery 100%, which is not good for battery life.

Does this make sense?

Chris

[ericb]

Chris,

I've been doing some research, and theoretically it should work.
I only want to run the cooler at a little above zero (C). The stirling cooler should use about 10 watts to keep everything at 3 degrees C while at 25 outside. At temperatures lower than 25, the cooler should switch off from time to time. etc.
If I'm wrong, I'll either have to pick a larger battery/panel or set the cooler at a higher temp.

I was curious if any other people have any experience with such a minimalist approach .

Eric.

[Tropic Cat]

I have a question... after 81 posts in this thread and several posters actively doing research and posting that they're lining up to by one of these coolers or cooling units, what's the bottom line?

Has anyone actually used one with decent results?
Do they work as advertised?
Will someone please post their actual experience?

The only results offered so far seem to be negative, yet this thread has been going on forever.

[witzgall]

We have used ours for weekend cruising with great results. The power cord (Cigarette lighter cord) shorted, but other that that, it has worked perfectly. I don't have an AH or AMPS meter, so I cannot tell you how much juice it has used, but I don't think is is alot. Our house bank was 150ah, just upgraded to 300ah, so I think this could be run on the highest cooling setting on weekends, and full time if we get some solar/wind power onboard. Ours sits on a piece of closed cell foam, on the sole of the boat, by the nav station.


Chris

Originally Posted by rickm505

I have a question... after 81 posts in this thread and several posters actively doing research and posting that they're lining up to by one of these coolers or cooling units, what's the bottom line?

Has anyone actually used one with decent results?
Do they work as advertised?
Will someone please post their actual experience?

The only results offered so far seem to be negative, yet this thread has been going on forever.

[witzgall]

OK, so 10 watts for 24 hours is 240 watts, or 20AH. You should size your battery at least 2x the # of AH you want to draw from them each cycle, if you want it to last any length of time, So you should be looking at a 40ah battery minimum. At the smaller size of things, you may not be drawing at the 20h rate, so the rated capacity of the battery may be less than what is specified for the 20h rate.

Then, lets look at the solar side of things. 18 watts is 1.5a@12v So for 5 hours, that is 7.5 hours. With OPTIMUM placement of the panel, in a place that gets full sun for 5 hours, you may get that. 7.5 ah. So you are drawing out 20ah each day, and depositing 7.5ah. This is a deficit.

Assuming your 10w draw (and I have not confirmed this on our unit) the I would think a 55ah battery and a 50 watt panel would do the trick - or my math is off (and that is certainly possible).

I assume that you are looking to put this on a small boat, perhaps one without an engine? Tell us more.

Chris

Originally Posted by ericb

Chris,

I've been doing some research, and theoretically it should work.
I only want to run the cooler at a little above zero (C). The stirling cooler should use about 10 watts to keep everything at 3 degrees C while at 25 outside. At temperatures lower than 25, the cooler should switch off from time to time. etc.
If I'm wrong, I'll either have to pick a larger battery/panel or set the cooler at a higher temp.

I was curious if any other people have any experience with such a minimalist approach .

Eric.

[ericb]

@Rick: I was wondering the same,that's why I posted. At least it's given a result

@Chris: I'm planning to use it at a camping site where I only need cooling. No other consumers present, apart from the incidental phone or MP3-player.
Since you actually use one, can you tell me if it's running fulltime on your weekend out? That's the one I'm curious about, since I'm calculating with only 25% running time. Plus, even if there is no direct sunlight, a solar panel will provide a (smaller) current. Let's say we have 15 hours of daylight. So, on an average summer day , we get about 5 hours of bright burning 1,5A, but the other 10 daylight hours will still give me a number of Amps.
I know, it's guessing. But that's also the fun of it for me.

Ericb

[witzgall]

Ericb;

You are right about the extra power, but most folks use 5-6 times the wattage as total output for the day. You never get 100% out of a system, even at the optimal time of day and angle. Trust me, I know about this fact - we have a 2kw array on our home, and our estimated power output, in sunny NC with good panel placement and southern exposure.

I don't think 25% running time at 10 watts when running is realistic. Have you read something that showed it would only run 25% of the time? I read something that a user reported .9 amps draw at the lowest colling settging this would be 100% duty cycle, not 25%.

I think it will be running all of the time, just more or less during the day and night. If you are using this at a camping site whre you can drive in, just get yourself a big deep cycle bat from Walmart or such (do they have them in NL?) and forget the solar - charge the batt at home.

Chris

I did run mine plugged into my truck overnight several times. I woould run it at the highest cooling seting while driving, and then at the lowest at night. Truck started fine.

[thezfunk]

I got one and I use it in my work vehicle to keep food and beverages cold. There have been hot days at 90 or so outside and obviously warmer on the inside of the vehicle where it runs for 6-7 hours on a car battery at the lowest cool setting which is about 38F degrees with no problems. Truck starts just fine at the end of the day. I love it and it does everything exactly like I wanted. Want to know anything else?

[ericb]

Thanks for the replies. I must admit I might have been a bit optimistic. However, there is only one way to make sure: just go ahead and do it
I'll just start with the 18W/15Ah. I can always add more capacity. Chopping things in half after starting big won't really work, would it? :P

Eric

[Tropic Cat]

Thanks guys, at least this is something in the way of feedback. I think I understand that both of these units are the small portable types and neither of you guys has current draw data over time or current plots in a tropical environment.

Has no one bought the stand alone Stirling cooling unit and added it to an on board refrig box?

When this thread began, I thought this thread was really on to something. Alas, it's been nearly 6 months and I'm getting close to a refrig/freezer refit and decision time. So, please forgive my impatience, I was hopeful there would have been a little more data to go on.

[thezfunk]

Originally Posted by rickm505

Thanks guys, at least this is something in the way of feedback. I think I understand that both of these units are the small portable types and neither of you guys has current draw data over time or current plots in a tropical environment.

Has no one bought the stand alone Stirling cooling unit and added it to an on board refrig box?

When this thread began, I thought this thread was really on to something. Alas, it's been nearly 6 months and I'm getting close to a refrig/freezer refit and decision time. So, please forgive my impatience, I was hopeful there would have been a little more data to go on.

If I am not mistaken...I think you just volunteered for a more indepth experiment.

I do just have the portable unit. Unfortunately, in these types of situations someone has to be the first to either try and succeed or try and fail. The great part about failing is that you end up learning quite a bit!

[Icetug]

To all, I have been using a twinbied unit for a about a month. I have installed it in an existing icebox on my sailboat. It is right now just sitting on top of the box with some insulation to seal up the opening. Far from the optimum but a test run anyway.

The existing box is not highly insulated and there is some leakage at the top. The small fan on the unit runs all the time and is marked on it that it draws .47 amp 12VDC so the unit will ALWAYS use this amount, even if the box gets cooled down. The company did tell me that the unit would shut down if it overshoots and gets a little too cold but don't bet on this ever happening if your box is very big. The box I have is a typical deep, approx 3 feet x 3 feet with some ood shapes more like a triangle that follows the hull. There are 3 temps available, refer, freeze, and deep freeze. I leave mine on refer and it holds about 38-45F even when the boat is 93F inside. Of course, it is running pretty much flat out all the time. There is an 8 amp fuse in the unit so total draw must be lower than that. I don't have a meter on the unit so I can't monitor performance all the time.

Bottomline is this so far. The twinbird will do the job. I am sure if I divide the box into two areas I can get it to freeze a small area and refer cool the other using an air bleed from the freezer. The fan runs all the time, so if you want total quiet then pass on this one (it isn't that loud though). It is a package unit so you must have the room to install it, although it isn't picky on how you orient it. Being a package it is very easy to install, no refrigerant lines to run, no thermostat lines, just poke it in an insulated box and plug it in. Obviously, the better your box the better it will run. It is expensive, however it is about the same cost as a compressor type unit if you figure in everything. It will run even if it is hot inside the boat without loss of efficiancy, something an air cooled compressor won't do.

As far as running this on a 15 ah battery and solar panel. Hey you can try it but I would have a good return policy so you can get a bigger one when you find out it doesn't work. The only way you could possibly get that rig to work is if your box has 4" of tight foam insulation and is about as big as an ice chest inside, and that would still be pushing it.

Hope this helps.

[Caribsailors]

Interesting Icetug,

If you could share the model number and where you purchased that would be great

Thanks for the explanation of your experiences

Cheers