Casita refrigerator needs 12 volts

[Brian B-P]

Originally Posted by Francesca Knowles

There are four sets of numbers there (see below)- how do you interpret that first row ???

At first glance I thought that was for 12v use when on gas/(converted)110...but it's the same as that given for 12v only!

Tom provided the translation of the first row, which corresponds to a feature item referring to energy consumption according to a European (IEC) standard. Dometic's product page for this model (RF60) gives a fuller version:

Energy consumption - according to EN ISO 7371,i.e.: 25 0C / 5 0C:1,90 kWh/24h

That was supposed to be

Energy consumption - according to EN ISO 7371,i.e.: 25 °C / 5 °C:1,90 kWh/24h

As per Euro practice, the comma is the decimal point. The 5°C value would presumably be the temperature maintained inside the refrigerator for the test.

This item is repeated as the consumption for operation on 230V AC. It is not the energy consumption for operation of the controls, because there is no outside-supplied power used for controls - as the specsheet says they are not electronic:

Thermostat electromechanic

The other reason it is apparent that this is the energy consumption of the controls is that it is far too much.

[Brian B-P]

Originally Posted by Francesca Knowles

There are four sets of numbers there (see below)...

The last three rows correspond to cooling on the three power sources: 12VDC, AC power (in Europe, with their 230V power), and propane gas. None of them include power for controls, because there isn't any - this model (the RF 60) does not have electronic controls.

This model has 110W heaters (AC and DC), which would use 110 W x 24 h/day = 2.64 kW-h/day if running continuously, so it appears to cycle on and off to maintain the set temperature, being on for about 1.9/2.64 = 72% of the time (17.3 hours/day).

The DC row expresses consumption in amp-hours (a useful number for a user considering how quickly their battery will be exhausted) and reflects always-on operation (because as the spec sheet explains the thermostat works only in AC and propane modes) at 12V. This corresponds to
220 Ah/24h x 12V = 2.64 kWh/24h, or
110 W x 24 h = 2.64 kWh/24h

The energy content of propane is 50.35 kJ/g, so the energy consumption per day on propane (assuming that their spec is for propane, not butane) is
50.35 kJ/g x 265 g/24h / 3600 kJ/kWh = 3.7 kWh/24h
The burner uses 11 g/h, which would be 50.35 kJ/g x 11 g/h / 3.6 kJ/Wh = 154 W
That's much higher consumption than with electricity. Propane operation is effective, because a lot of energy is carried in a filled propane tank compared to a similar mass of charged battery and the burner has higher output than the 110 watt electric heaters, but it is not very efficient, presumably because the heat doesn't transfer very efficiently into the refrigerator system.


By the way, this sample model (RF60) should have similar performance to small RV refrigerators, but it is not for use in RVs.