Building your own fridge or cooler

[PaulC]

Thanks Madjack, I'll go back to cruising the forum now I must be the dumdum here, Waeco use exactly those for their coolers.
Cheers
Paul

[mikeschn]

Hi Mike

My thought was the thermoelectric unit was small, and it was 12v, and I could build it into the lid of the ice box.

All true, but with a major problem 92 Amps a day that needs to be one hell of a battery.

I can hear you thinking only run it part of day

If you only intend to run it part of the day, another big problem rears its ugly head, when its switched off, it becomes a thermal link to the outside temperature which means rapid warming of the interior.

The other reason they dont like ice inside is because the unit is a thermal bridge condensation will quickly form on the thermo unit, its ok to use thermal packs (those sealed blue eutectic blocks)

Okay, so it sounds like I won't be using it long if I am rustic, unless I have a couple batteries, and my solar panel. Still, it'll work okay while I am driving.

It also sounds like I need two lids... one with the thermoelectric unit, and one without.

Are you going to have a little corner of your spreadsheet calculating the electrical consumption of the thermoelectrics?

You never did say if there was a good 110v option (with an inverter) to do what I am trying to do, both mechanically and electrically.

Mike...

[GeorgeTelford]

Hi Paul

As far as I am aware I have not mentioned 120V thermoelectric units.

Hi Mike

Reccomend a mains unit?, Over here all fridges arre ranked in efficiency classes, The unit I experimented on in the motorhome was class B (Class A being the best) it was rated at 210,000 KWhr/yr this averaged 3 Amps per hour after invertor losses, with no extra insulation. For the mathmatical amongst us the fridge powered with no invertor losses would be around 2 Amps hr

Lets take a class A fridge this would only require 2.18 amps (this is the first one I found online, rated at 153,000KWhr/yr, would be 1.45Amphr without invertor losses) This is with the standard one inch if you are lucky insulation, lets say we can halve the heat loss with best efforts at insulation that would be a tiny bit over 1 Amp per hour

Now a single 100 Amphour battery would cover 2 days using 50 Ah, this doesnt allow for the fact that when traveling we could take the power from the alternator to the battery Via a split charge DIODE

But how long Rustic (days)? and is there much traveling or all on one spot?

[mikeschn]

Well a typical camping trip is from Friday evening til noon on Sunday.

While many trips land us in an electric campground, there's been a couple trips that landed us in a rustic area.

Maybe once I've crunched the numbers (with the help of your spreadsheet) I'll realize I need a different plan. That's why I am thinking "ice" box, using thermoelectric only when it makes sense.

Mike...

[GeorgeTelford]

Hi Mike

thats not even 2 full days,

DIY Top loading "cooler" with muchos insulation, use eutetic blocks, 2 lids if you really want to use the thermo gubbins (but for 2 days it wouldnt matter)

[mikeschn]

George,

You're not going to give up on the concept already, are you? What about the guy who wants to take that same setup to Alaska.

Or what if Heikki wants to come and visit England with that setup?

Or what if I want to go to Flordia for a couple weeks?

Mike...

[cracker39]

I've used a 110v/propane fridge in a pickup camper I once had and it worked great. I even ran it on propane while driving as the side wall vent didn't let in enough moving air to disquingish the tiny flame that powered it. Besides, if the flame went out, the gas shut off. You had to hold down a button on the gas valve until the flame heated heated a spring inside that held the valve open.

Hijack??? Maybe, but it is realated to coolers.

Now, it's KISS time. A while back, WM had a simple, but sturdy, medium size styrofoam cooler with sides that were straight up and down (perpendicular to the bottom) for less than $6. I failed to buy one when I saw them, thinking I could get one later...wrong...they no longer have them. What I planned to do was build a "box" around it with another 2" of foil-backed foam insulation (for a total of 3" - 3 1/2" of insulation) and duct or plastic tape, including a second lid, making it a "super coolbox". I'd use a regular cooler for the food and drinks in the TTT, and keep my super coolbox in the truck to hold the spare ice.

Sorry for the interruption, George.

Now we return this thread to the world of mechanical/electrical coolers.

[GeorgeTelford]

Hi Dale

Thats no Hijack it totally on topic.

Why not make the whole thing? the plastic on a bought unit acts as a thermal bridge....

why not use these instead of ice?



Saves draining melted ice, easily reuseable

[apratt]

George, I really like the principal behind the Esicool. Is there plans out there to show how to make something like that. It reminds me of a hanging cooler that is wraped with canvass and the top part of the canvass is tucked in a pan of water. The canvass keep itself wet by soakiing itself with the water and with the wind it keep everything cool inside. I just like to have something that I can keep in the galley. Thank for the info you have.

p.s. also I like to build it like a cooler (top loading, so the cold says inside)

[cracker39]

Hi Dale

Thats no Hijack it totally on topic.

Why not make the whole thing? the plastic on a bought unit acts as a thermal bridge....

With the styrofoam cooler as the internal part, adding foam insulation, there would be no plastic...just layers of foam and foil backing on the outside to reflece heat.

why not use these instead of ice?



Saves draining melted ice, easily reuseable

The re-freezable packs are a good idea. Also, I can use half-gallon milk jugs of water frozen. When it melts, you have drinking water. The milk jugs are better than 2-liter bottles as they are square and fit better in the cooler. Also, water frozen in large baggies can be used. You have ice in these to break up and put in drinks.

[Guy]

Dear Gearge,

Any way to combine your ideas with this link
http://www.tnttt.com/viewtopic.php?t=2997&start=0&postdays=0&postorder=asc&highlight=making+icebox

I also found another idea in Sail magazine where the author took an Igloo cooler, cut out the middle, joined two parts, insulated it heavily.

[GeorgeTelford]

Hi Guy

I am just holding forth on the subject at the moment, that is a very good article though.

Hi APratt

I dont know of any plans, it is basically an absorbed water jacket and does work on the basic evapouration principle.

Hi Mike

Not giving up, but this is only a discussion of principles, what happens and why, I am considering maing up a test rig/prototype though.

Night for now though, need some sleep