Norcold freezer and laws of thermodynamics

[boywonder]

Originally Posted by rob_gendreau

So now I'm wondering if it makes sense to put anything in the freezer. I suppose a few frozen meals would help in the first few days (I typically keep the thermostat quite low unless I've got something really critical like some dairy or prepared food). And then just consume them. It would seem that it would then have no effect on overall power consumption if I just leave the freezer compartment empty. Is that correct?

The stackexchange answers are the correct answers....makes no difference from a thermodynamic standpoint. The fridge will use more energy and take more time cooling the added mass (whether it's popsicles in the freezer or beer in the fridge), but once the added mass is cooled there is no additional heat to remove.

If the popsicles are frozen and the beer is chilled, then not much more time or energy required since they already have their heat sucked out of them.

The specific heat capacity* of the added mass will help minimize temp swings when the fridge is opened repeatedly though since the specific heat capacity of water (beer and popsicles) is much greater than air.

*Specific heat capacity is the amount of heat that you need to add or remove from a material for a given change in temperature.

[arctictraveller]

Cold beer is SO important that doing what ever it takes to get it and keep it that way is well worth the effort. Saving any amount of amp hours is a worthy goal if it keeps the beer or food cold longer, but it's pretty easy to design around any slight inefficiency. If there was a big difference between keeping the refer only half full or completely full it would make sense to do what's most efficient, but it seems it doesn't make any difference once stuff is chilled. I'm glad I now know that.

[velo47]

If you were English you wouldn't have such worries about cold beer...

You know why the English drink warm beer?

Lucas refrigerators...

Matt
former owner of a 1972 Lotus Europa.

[LenS]

Some data on refrig. The first is my home modified Igloo refrig.

[rob_gendreau]

Cool! (heh). Thanks for the data.

[arctictraveller]

Originally Posted by velo47

You know why the English drink warm beer?
Lucas refrigerators...

You mean the Prince of Darkness?

Former owner of several TR4s and other English cars.............

[shadetreevanman]

I leave my Engel fridge on 24/7/365. I added enough solar so I didn't have to worry about turning it off.

Anecdotally, it seems to me the fridge stays colder inside with something stored in there. Or maybe that's just what I tell myself. If it's not loaded for camping it gets stocked with beer and water.

Before this upright fridge I had an Engel chest style fridge. I believed it stayed colder if loaded, and I left it on 24/7 too.

As a former owner of an MG B, Lucas is a cuss word.

[boywonder]

Originally Posted by shadetreevanman

I leave my Engel fridge on 24/7/365. I added enough solar so I didn't have to worry about turning it off.

How much solar do you have?

[shadetreevanman]

Originally Posted by boywonder

How much solar do you have?

Its not that I have a lot of solar, just 200W solar, and 210AH of Deep Cycle Batteries. Living in sunny SoCal I've found that to be sufficient to keep the fridge running and the batteries in good charge.

When I had the same batteries and only 100W of Solar, the fridge ran 24/7 too, but wouldn't recover quickly or even completely on overcast days.

When camping we're not big power users though, just the fridge, water pump, a few LED lights, phone chargers, and the occasional diesel heater.

I purposely do not have a 110V inverter in my van because I don't want to need more solar or batteries.

[arctictraveller]

My refer runs for months at a time. 300w of solar keeps the batteries topped up even in the winter when it's always overcast. 200w wasn't really enough unless I was in clear weather. I run interior lights, an inverter, tv/dvd once in while, regular heat on winter mornings, and the stereo.