Refrigeration and freezing

[Zizzer_Zazzer_Zuz]

I'm back from family obligations and ready to get this project in full gear.  I'm planning a trip to NY to buy a bus.  Maybe the week of Thanksgiving. This thread is not about buying the bus. Here, I am hoping for some insight from the communal knowledge concerning cold food storage, especially frozen food. I will be traveling alone and have my sights set on a shorty school bus. 

My current thought process goes something like this.  A freezer large enough to store several pounds of meat/veg/convenience but also able to freeze bottles of water.  Those bottles of water would be shared with a traditional cooler that would act as the cold storage for day to day use.  I'm hoping to be able to swap bottles, melted for frozen, once a day maybe and never opening the freezer again that day.

- Cons
Power Consumption
cost
Size
noise
manual, swapping ice bottles

- Pros
modular
fridge+Freezer (or just fridge)
Spare cooler
never buy ice

I intend to build vented but insulated cabinets for the fridge and cooler. I will be running on 12v but MIGHT consider LP.

My questions run along the lines of how many Ah are needed for a battery bank to run it? How quickly will one freeze water bottles? Would it be better to just get a combo unit?

Yes, I know ambient temp will play some part in the cost to run as well as the time it takes to freeze water bottles. I'm just looking for rough numbers and suggestion.

 

[highdesertranger]

the absolute best would be to have 2 separate 12v volt units. one for a freezer one for a refer. this would give you maximum storage. I run 2 off 2 deep cycle 12v batteries and 160 watts of solar. when I build my trailer I will switch to four 6v batteries, a lot more solar and add one more refer. highdesertranger

 

[Spaceman Spiff]

Agree with highdesertranger.  You would be able to go with a smaller freezer (or store more food the bigger one) and have cold beer in the refrigerator one; no ice needed.

My problem with ice chests is that the good ones are good at keeping food cold but suck at bringing stuff down to temperature.  I takes a lot of energy to bring a can of beer down from 70º to 35º.

 -- Spiff

 

[SternWake]

If building cabinets around a fridge, one can also just build a super insulated fridge with a danfoss compressor.

4 inches of foam on all sides and a well ventilated cooling unit is as good as one can do.

http://www.vfamerica.com/eng/coolingunits.html

The thing I do not like about coolers and Ice, or frozen bottles, is that they rarely keep the whole cooler and everything in it sub 40F.

Freezing bottles to keep a cooler cold, will use more energy than keeping a fridge at 38f. if you need a freezer and a fridge, Then HDR's solution makes most sense to me.
I have a freezer compartment in my fridge, and all i put inside of it are ice trays, and i can't remember the last time i used them.

Someone no doubt could calculate the BTUs needed to turn a known volume of water to ICE and then infer how much energy is required to do so via a compressor fridge/freezer and add estimate inefficiencies, but that person is not me.



This site has a lot of good info on battery powered refrigeration:
http://www.kollmann-marine.com/

 

[MrNoodly]

I takes a lot of energy to bring a can of beer down from 70º to 35º.

And WAY more to refreeze a gallon jug of water.

 

[MrNoodly]

And WAY more to refreeze a gallon jug of water.

And for the cost of enough solar and batteries to refreeze a gallon of water a day, you could buy a second fridge instead of using a cooler. Maintaining the temperature in a fridge or freezer requires less power than recovering the temperature after warmer things have been placed in them. And you don't need to keep worrying about the status of frozen jugs, either in the cooler or the fridge. Besides, when you put a gallon of ambient-temperature water in a freezer, the first thing it does is defrost the food you're trying to keep frozen. Repeated freezing/thawing is bad for food.

 

[Zizzer_Zazzer_Zuz]

the absolute best would be to have 2 separate 12v volt units.  one for a freezer one for a refer.  this would give you maximum storage.  I run 2 off 2 deep cycle 12v batteries and 160 watts of solar.  when I build my trailer I will switch to four 6v batteries, a lot more solar and add one more refer.  highdesertranger

Sure, two units would be great but pricey.  At some point I would just be better off with an over/under.

I'm hoping to start with about twice that much solar.

I'm 90% convinced to having a tow bar and trailer lights installed pretty much day one. Not sure if I'm going to tow a car, a small trailer or just hand a utility box off the back. Regardless it seems a good investment.

 

[Willy]

A number of 12v compressor coolers have 2 compartments (Waeco CF-50 is one), with the main 1 able to freeze food while the 2nd smaller 1 (above the compressor) act's to keep food just cold. I think Whynter makes 1 with 2 separately cooled sections. I have an Engel and a Waeco, one used as a freezer and the other a fridge. I prefer having 2 units in case 1 bites the biscuit. ..Willy.

 

[Almost There]

A number of 12v compressor coolers have 2 compartments (Waeco CF-50 is one), with the main 1 able to freeze food while the 2nd smaller 1 (above the compressor) act's to keep food just cold. I think Whynter makes 1 with 2 separately cooled sections. I have an Engel and a Waeco, one used as a freezer and the other a fridge. I prefer having 2 units in case 1 bites the biscuit. ..Willy.

And I prefer the two separate units because the combination units have it divided up so that neither section is big enough for much of anything.

The best way to figure out how  much fridge or freezer space you need is to go to your own fridge in your S&B and pull out all the things you absolutely must have when you move to the van. Allow for using smaller sizes if you're used to buying the jumbo size because you'll quickly figure out that it just won't all fit.

Now, take some cardboard and using the inside dimensions of the unit you're thinking about, build the inside of the fridge. Don't forget to allow for the little shelf they all have!

Load the cardboard dummy fridge with your stuff, figure out what you're not going to be taking with you until it all fits.

Then decide if the fridge is going to be big enough for you or whether you wan to move up a size.


Note: I have a pair of 65 qt Whynters after playing with the above. The fridge is barely big enough, the freezer is just about right.

 

[907KHAM687]

I use a freezer and a small cooler. I have two blue freezer pacs, I switch them out every other day at most. Anything I defrost goes into the cooler so that energy isn't wasted. I understand that this isn't the most energy efficient way to refrigerate, but I would guess that investing the fridge cost of 500-800 dollars in additional solar/batteries/high output alternator/generator would be more efficient and add flexibility to the system.

Two units would be nice though.

 

[Norcalauren]

Need 12 volt cooler for car. What brands are best? Anyone have experience with Coleman powerchil coolers?????

 

[SternWake]

Are you aware that you cannot run thermoelectric coolers for long with the engine not running? They are powerhogs, consuming about 4x as much electricity as the ~500$ 12vdc compressor fridges, and will kill your battery dead as a doornail if left plugged in overnight.

Thermo electric coolers can also only achieve, at best, about 40 degrees F below ambient temperatures, so at 81F it can only do 41f at best, and under 40f is the threshold for safe food storage.

One of the least expensive 12vDC compressor fridge options is this:
http://truckfridge.com/tf31.html

They have 41 and 51 liter models too.

Cheapest from this guy:
http://www.westyventures.com/parts.html#cart_restore

 

[Woltz]

Here is a few different people selling solar panels. Because you didn't say which part of New York, just figured the city would be a all around. I figure if you don't have any panels, you would have to look for them to power this beast. The last link might be best.

75 Watts for $50.00 Each Panel
http://newyork.craigslist.org/que/ele/5925941172.html

245 Watts for $180.00 Each Panel
http://newyork.craigslist.org/que/for/5900861793.html

175 Watts for $100.00 Each Panel or Best Offer
http://newjersey.craigslist.org/mat/5868243924.html

295 Watts for $150.00 Each Panel
http://newjersey.craigslist.org/mat/5872705628.html