Camping Refrigeration and Cooling

When it comes to the power efficiency of a 12 volt camping fridge – up until recent times, there has really only been two main factors that have been the core focus when talking about reduced power consumption. They are insulation (cabinet insulating quality) and compressor (motor).

 

Jarrod & his very own refrigeration & energy system. Totally independent & off-grid.

Insulation:

Just like a traditional camping icebox – the better the insulation, the longer the ice holds (the colder your drinks stay for longer). A 12volt travel fridge is exactly the same – the better the insulation, the longer it stays cold and less your fridge compressor needs to run (less power you use).

Compressor:

The compressor (motor) pumps the cooling refrigerant through the fridge (cooling your food) and it cycles throughout the day (ie: just like your household fridge freezer, you will hear it start and stop periodically throughout the day/night). With the temperature settings or dial on the fridge, the colder we want the fridge (ie: to freeze) the longer the compressor runs each hour. The warmer we want the fridge (ie: to refrigerate) the less it runs per hour.

There is a difference in compressor sizes and this is often determined by the size of the insulated cabinet and – or – how well insulated the cabinet is.

The Condenser:

There is a third major contributing factor that determines the efficiency of a 12volt travel fridge and that is it’s condenser system. A condenser is a bit like a radiator on a car – it gets rid of the heat out of the fridge – ie: food, insulation etc….  In short, the easier and quicker a condenser can get rid of heat, the less the fridge will run, the more power efficient it will be and this is why a good quality condenser is so important.

Here’s what the internal workings of a fridge look like. Mesh grid on right is the condenser

Different Condensers:

What I have decided to do is to show two entirely different condensers – why they are built the way they are, and the benefits of each.

Finned Condenser:

A finned condenser is mainly used in applications where there is a very small area allocated (ie: built into the bottom corner of a fridge.). The fins on a finned condenser are very compressed close together due to the lack of space available – the idea is that many fins create as much surface area as possible and act like a heat sink… ie: designed to disperse as much heat away as possible.

 

Positives:
More compact: Being built into the bottom corner of a fridge makes the overall external fridge size/dimensions quite compact. Great for vehicles with limited storage space.

 

 

More internal volume: The area above the compressor/condenser is not wasted… giving more internal cooling space.   

Negatives:
Noisy: Because this condenser system is built into the bottom corner of the fridge, these built in systems need all the help they can to get rid of heat. So a fan is mounted directly behind the condenser to suck air (air is sucked horizontally from one side of the fridge to the other,) through/past to help cool (ie: like a radiator in a car). These close fins create significant air/fan noise – what sounds quiet in a camping showroom floor can sound like a jet engine in the peace and quiet of the outback. 

 

They block and need constant maintenance: Because there are so many fins that are so close together – they tend to constantly block with a matted blanket of fluff. This blanket forms a shield and doesn’t allow the air to suck past the fins easily and therefore the fridge stops getting rid of the heat it needs to. In turn, the fridge runs harder – uses more power and wont cool as well. I have seen so many of these full of lint and a combination of talcum powder type bull dust. This also increases the noise.

Contains heat: A finned condenser is often surrounded by a steel plate that wraps around it (containing the condenser in one unit), this unfortunately helps to hold the heat in – especially when the compressor stops. In most cases the fan stops in unison with the compressor. (Please note: In some fridges, the fan will still operate after the compressor stops – this will continue to use power.)

Condenser surrounded by a steel plate

Wire on Tube Condenser

Wire on Tube Condensers are usually found on the end of fridges & this is mainly because of the extra area they require. The cooling tubes / wire is spread out & this makes it easier to disperse heat away.

Positives:

Eradicates heat easily: This type of condenser system has a vent on top of it – as hot air rises naturally, it is always dispersing heat even when the compressor and condenser fan are turned off. This means the fridge runs less, is quieter and can be more power efficient because of it.

Super quiet: This type of condenser has the cooling tubes that are spread out over a large area. There is a larger cooling fan, which doesn’t need to run as hard and that’s because it is mounted at the bottom of the fridge and pushes upwards (simply cycling air in a low volume and therefore impeccably quiet manner).

Minimal maintenance: Because the tubes are spread so far and over a large area, they are easy to clean if required and the chances of a fluff blanket forming are basically non-existent! The fridge runs more efficiently and there is less (virtually nothing) to worry about with maintenance from this perspective.

Uses less power: Because a wire on tube condenser gets rid of heat easier and quicker (than a boxed in finned condenser system) – it doesn’t need to run as hard / often and therefore is way more power efficient in most cases. The less power you use, the less solar energy you need (massive cost savings here) and this most definitely makes for a far more relaxing camping experience (less stressful).

Negatives:

Bigger Footprint: The negative for wire on tube condensers is the fact they take up more room as they sit on the entire end of the fridge – making the overall footprint of the fridge slightly bigger when being stored in your vehicle. (then again, do you use a bigger footprint – or – create more internal fridge area? I’m not sure which way to look at this, but I think the efficiency on battery power would far outweigh a slight bulkiness).

Last thoughts:

My desired outcome from writing this blog came about because of my distaste for poor quality produced travel fridges on the market – they are a dime a dozen at the moment and often the same fridge with a different colour or name (all telling us their fridge is better than the other!). The end loser is you… the customer. Being cheaper, these fridges definitely save us all a few dollars initially (I’m not against that by the way.) – but because of the inefficiency, we all end up spending more money on bigger battery systems or larger solar power to drive them. It would appear that is a short term gain for a long term loss!

If you’re looking to buy a fridge now or in the future, I would look at three core features:

  1. Great quality insulation and tough cabinet quality
  2. A quality compressor / motor with a reputable brand
  3. An exceptional condenser that can get rid of heat easily (nice and large, easy to service)

If you have any questions, please feel free to contact me personally via email (via filling out the form below) – or – call us on (07) 5479 3300 direct. I look forward to hearing from you!

Cheers,

Guru. 

One Comment

  • Roger Waskow says:

    Hi Jarrod

    There are a few FB sites I subscribe to and it would be great if I could put this info on them. Just wondering if you could send this to me in a format to put on FB. Also with your name and business details.

    Thanks

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