Keeping food cold

Refrigeration is the most common form of food preservation for 'dwellers , although drying and canning also work for some foods.

Note that many 'dwellers choose to use no refrigeration at all.

• Pro - low cost, low empty weight, zero power consumption and widespread availability.
• Con - constant need to add frozen material and the requirement to dispose of any melted ice. You lose significant amounts of interior volume due to the space taken up by the cooling material.

Tips to make cooler use more effective and simple:

• store your cooler out of direct sunlight and in the coolest place available
• small coolers (L'il Oscar, etc) are often found in thrift stores for a few dollars
• ice-free methods
  • if you have regular access to a freezer at work or elsewhere rotate blue freezer packs in/out of the freezer and into your cooler. This removes the ongoing cost of buying ice but requires a number of packs so you can always have them in rotation.
  • nearly-filled bottles of water¹⁾ are free and work much like the freezer packs above.
  • in any case, having three sets in rotation allows each set to be in the freezer for 32 hours (24hrs + 8hr shift) rather than just an 8hr shift.
• if using ice
  • block ice will last longer than cubed ice
  • store food in a tub or other container to keep melted ice off it
  • use a cooler with a drain at the bottom. This makes cleaning/draining easier and may allow you to reclaim any clean water for washing or other purposes.
  • you may be able to harvest ice from trays or an icemaker at work. If doing this, remember to leave enough ice for others, refilling ice trays, etc.
• use cold weather to your advantage (see below)

A refrigerator (refer or reefer) is used to keep items at a given cool temperature, typically ⇐40F.

Refrigerators give off heat and must be ventilated; ensure any vents exhaust into open area. Cooling performance may be enhanced by adding fans to move more air across the condenser²⁾ and dusting components regularly.³⁾ Cold retention can be enhanced by adding insulation in the form of foam sheets or insulative covers made for the cooler.

Front loading or “Upright” refrigerators are square or tall rectangles shaped like residential refrigerators. They stand up and have a door that opens off the side.

• Pros
• Direct access to the contents from a walkway
• Space above unit remains usable
• Easier to load and unload for many people. Fewer “hidden” foodstuffs.
• Con
• Doors can sometimes swing open in transit.
• Items may shift and fall out when the door is opened.
• Cold air “spills” out when the full-height door opens, which has to be re-chilled and leads to higher power consumption.

Top loading refrigerators are usually low rectangles shaped like insulated coolers.

• Pros
• Can be filled to capacity more easily.
• No worries about doors swinging open and items falling out when vehicle moves
• More efficient. Better cold retention due to a lack of a bottom seal, and cold air doesn't spill out when opening the door, which may reduce power consumption if the door is opened frequently.⁴⁾
• Cons
• May have to dig for food. Easier for things to get lost/overlooked, or crushed (especially soft fruits).
• Space above top door unusable unless placed in a slide-out or similar.

Absorption (ie, propane-powered ammonia cycle) fridges were popular in RVs because they used minimal power to run the ignitor, control board, fans if any. This type of fridge had to to be quite level so the ammonia cycle cooling would work by gravity; there is no pump.⁵⁾ Using one out of level could damage the $$$ cooling unit.

These fridges are often called three way fridges because they run on propane in the field, provide heat for the absorption cycle from 12v while driving, and from shore power when available. The fridges are very efficient (both propane and 12v controls) on propane, but use a great deal of power to run off electricity.

Absorption units are rare in vandwelling setups due to size, expense, and need for exterior venting.

Over the last few years RV refrigerators have been going to 12v or, more commonly, 110v residential style units.

Words of Wisdom: “Check amps drawn [by the compressor fridge] over 24 hours, much more important when boondocking than purchase price.” – John62CT⁶⁾

12v compressor refrigerators become the standard way to chill food in solar-equipped vans. The main types of compressor fridges common in 'dwelling setups are:

• Danfoss-style compressor – Now made by Secop, these compressors have a reputation for quality. Brands include:
  • Vitrifrigo used by Sternwake⁷⁾
  • ARB used by Arctic Cat⁸⁾
  • TruckFridge used by akrvbob⁹⁾
  • Indel B 50-liter used by corttt¹⁰⁾
  • Dometic used by Mobilesport¹¹⁾
  • Iceco VL45 recommended by doc-ketamine¹²⁾. Measured 85w when compressor is running
  • Iceco JP50 recommended by panchulio.¹³⁾
  • IceCo Dual Zone Series recommended by Princess_Fluffypants. Great for people who want capable freezer space

• Sawafuji-style compressor – this compressor has one moving part and is energy efficient with low startup current.¹⁴⁾ This kind of fridge is least likely to be damaged by rough use in the outback. Downsides: initial expense, the oscillating piston can be noisy. Brands include
  • Engel used by Luciano151¹⁵⁾ and Arctic Cat¹⁶⁾
  • undertheaxles uses a Engel MT35F, and reports it consumes 12A each day.¹⁷⁾
  • Engel MT45 used by goldendinnerplate¹⁸⁾

• non-Danfoss-style compressor brands include:
  • Grape Solar used by bcbullet¹⁹⁾
  • Whynter used by towhee²⁰⁾
  • Dometic used by Every Road Leads Home²¹⁾

Note that using a compressor fridge for refrigeration vs. freezing can have vastly different power requirements:

“I use a pair of 65 qt Whynter units, one as a fridge, one a freezer. The freezer uses somewhere around 4 to 5 times the power that the fridge uses. Keeping the fridge at 40F is fairly easy, keeping the same unit at 0F is another story.” – Almost There²²⁾

The Engel MT series (MT35, MT45) are reported to have very low current draw due to clever cooling airflow design.²³⁾

Secessus describes the interior size of the Alpicool 15L (flat lid) version:

I store leftovers in pint and quart mason jars, which stand up fine in the [Alpicool] 15L. Longneck beers are slightly too tall. Since glass is heavy and harder to compact for trash removal I buy beer in cans anyhow. 16oz tallboys do fit. ←- the info discerning gentlemen need to know²⁴⁾

Some have reported good results with inexpensive “dorm” refrigerators, especially when external insulation is added.

PRO

• inexpensive
• widely available

CON

• not designed for mobile use
• typically only available in front-loading
• typically not optimized for power use
• typically not well-insulated
• requires 24/7 inverter use, with inefficiencies while running and parasitic losses while still.

Further reading:

• discussions on /r/vandwellers
• discussions on Vanliving/CRVL

Peltier cooling doesn't get used much in solar setups because it uses a lot of power and does so 100% of the time. A typical Peltier cooler might run 4-5A continuously whereas a compressor cooler might run 5A 30% of the time and turn off the rest of the time. The 100% duty cycle issue can be alleviated by wiring in a 12v thermostat.²⁵⁾

This kind of device cools to ~30-40F below ambient, which may not be a problem if the ambient is 80F or less. For best results avoid putting hot or even warmer-than-ambient items in the cooler. Use a fan on the item until it is room temp before placing in cooler.

Most lack thermostats and so can accidentally freeze food if ambient temps are low enough.

Read the manual before purchase to see how long it can be run at a stretch; fans are a common failure point when run 24/7.

• you have a surplus of power: you are hooked up to shore power, have a large solar install, or are running your heavy loads on an opportunity circuit.
• you are in an area where ambient is less than 80F and the cooler has a thermostat (or you wire in a thermostat/relay). Most snowbirds stay in areas that are <80F.
• you want to chill nonperishable items like water, beer, etc or semi-perishables like cheese and salami.
• you already own one and run it on a Low Voltage Disconnect so it doesn't run down your batteries

In low humidity areas with a significant day/night temperature differential you may be able to cool or even freeze cooler packs and water bottles. Leave them outside overnight and put them back in the cooler in the morning.