Guest post by National Luna

PART2: How much power does a camping fridge use at different temperature settings?

In last month’s blog, we looked at how ambient temperatures affect your camping fridge’s power consumption. We did this by comparing the energy efficiency of a common camping fridge, where the internal temperature was set at 4ºC, and the ambient temperature was altered through 21ºC, 32ºC and 43ºC.

By keeping the fridge’s temperature fixed 4ºC, and only altering the ambient temperature, we were able to highlight the impact that external conditions have on a camping fridge’s energy use. In this particular example, the energy used was roughly 3 times higher (within a 24-hour period) when comparing the fridge’s performance at 43ºC as opposed to 21ºC.

The lesson: If possible, try to keep your camping fridge cool, well ventilated, and away from direct sunlight and/or high-ambient conditions. In case you missed it, you can read that blog piece here.

This month, we’re looking at how various temperature settings affect the energy use of the same 60-litre single-compartment fridge. We’ve done this by following the same methodology as last month’s test, however, in this case, we’ve fixed the ambient temperature at 32ºC, and then fluctuated the fridge’s settings through +4ºC, -6ºC and -16ºC.

This allows us to “exclude” the effects of ambient conditions, and focus solely on how various temperature settings affect a common camping fridge’s energy consumption.

The following graphs depict this best…

With our 60-litre test fridge set at +4ºC, the unit’s compressor cycles on 18 to 20% of the time within a 1-hour period. All three tests were conducted at an ambient temperature of 32ºC.
Dropping the internal temperature to -6ºC, more than triples the energy used within a 1-hour window.
A further decrease to -16ºC sees the power consumption almost double to what it would be at -6ºC. Bear in mind that – in the short term – it’s often unnecessary to freeze food beyond -6ºC. Naturally, if this setting was used at a 43ºC ambient temperature, the energy used would be significantly higher.

KEY POINTS

As mentioned in our previous test / blog, the greater the difference between the fridge’s internal- and external temperatures, the faster these two temperatures want to equalize.

That said, your fridge’s insulation is the only barrier that’s slowing down this process. Given that insulation is never 100% effective, eventually, some loses will occur and the fridge’s compressor will have to cycle on in order to replace the lost energy.

In short: Decreasing your fridge’s internal temperature has the same effect as raising the external / ambient temperature. The worst-case scenario would be if the internal temperature was set very low, and the ambient temperature was very high. In this case, it’s not uncommon for the compressor to run 100% of the time.

TEMPERATURE SETTING TIPS

Of course, very few things are better than an ice-cold beer in the bush, however, it pays to be mindful of how “ice-cold” temperatures impact the energy use of your camping fridge.

Generally speaking, most household fridges operate within a 4ºC to 7ºC range. Setting your camping fridge any lower than that may be unnecessary in terms of power consumption.

That said, it can be a good idea to set your fridge’s temperature super low while you’re driving – when the fridge is drawing power from the vehicle’s alternator – and then to adjust the temperature upwards once you get to camp and the fridge is running on battery power.

By doing things this way, you not only ensure that your drinks are cold when you get to camp, you also reduce how much work the compressor has to do thanks to residual cooling.

In much the same way, if you have a dual-compartment fridge, it can be helpful to deep-freeze ice bricks and/or meat in the freezer section while you’re driving, then, once you get to camp, adjust the temperature setting upwards (approximately 7ºC), and move the ice bricks / meat to the fridge section where it can slowly defrost and assist with keeping things cool.

In closing, perhaps the most important lesson of all is knowing that optimum energy efficiency requires a hands-on approach – both in terms of mitigating the effects of high-ambient temperatures, and, to actively adjust your fridge’s settings to best suit the conditions of the day.