Thread: Primus fridges

Yes me old mate - basically it works on the absorbtion process - either using amonia or lithium bromide mixed with water.

The system works - the same way as a 2 or three way caravan fridge - the heat source - gas or mains electricity (or 12v if a 3 way) heats an area - where the amonia of LbR boils out of the water and rises, as it rises it enters a condenser secion - cooled by ambient air, this conenses the relatively high pressure vapour into a high presure liquid which - due to the pressure - is then squeezed through an orifice/measuring device (tx valve equiv) where the high pressure liquid is then alowed to expand into the evaporator - as the pressure drops the temp drops - and you have cooling.

Its the same - almost as any fridge - but you are replacing the compressor with a heat source to raise the temp - thus the pressure.

Not as efficient as a compressor driven system - they take a while to pull down - but if you are out in the bush with no power they are good. Hook up a lpg cylinder to them and off you go.

If you want it for use in the car ( ie. touring ) get an Engel or Waeco compressor fridge ( range from $800 to $1200 for 40 -60 litres ). An absorption fridge draws heaps from your battery ( 8-10 amps ) continuously and for that is not very efficient.

If you want one as your "base camp" fridge, running off gas, or mains, then this might be worth considering, but it does sound a little pricey for an absorption fridge. It won't be much good in the "tropics". note it only cools down to 30 degrees below ambient. If you're in a 45 degree day its not going to keep your milk at 4 degrees.

A compressor fridge will cool to whatever temp you set it to.

Originally Posted by waynep

If you want it for use in the car ( ie. touring ) get an Engel or Waeco compressor fridge ( range from $800 to $1200 for 40 -60 litres ). An absorption fridge draws heaps from your battery ( 8-10 amps ) continuously and for that is not very efficient.

If you want one as your "base camp" fridge, running off gas, or mains, then this might be worth considering, but it does sound a little pricey for an absorption fridge. It won't be much good in the "tropics". note it only cools down to 30 degrees below ambient. If you're in a 45 degree day its not going to keep your milk at 4 degrees.

A compressor fridge will cool to whatever temp you set it to.

Sorry Wayne I have to slightly disagree here - especially if the system is using lithium bromide or amonia, the evaporation temp (at a 40 Deg C + ambient) is still going to be in excess of minus 5 Deg C,

There has been a vast improvement on these new systems - especially with the expansion device and they are far better than they use to be.........

However pull down times are bloody slow - and for the cost a compressor driven one has to be the better option.

Originally Posted by ladas

Sorry Wayne I have to slightly disagree here - especially if the system is using lithium bromide or amonia, the evaporation temp (at a 40 Deg C + ambient) is still going to be in excess of minus 5 Deg C,

There has been a vast improvement on these new systems - especially with the expansion device and they are far better than they use to be.........

However pull down times are bloody slow - and for the cost a compressor driven one has to be the better option.

What ...disagree with me ...how dare you...you think you're some sort of expert on this subject or something

Aldi are selling 3 way 42 litre absorption type fridges at the moment for $299.

Dunno how good or bad it is though. :/

thanks for the info, I already have a compressor fridge for touring but am looking for something bigger for week long fishing trips, especially the freezer bit.So more questions, how much gas do these babies chew, i know that is dependant on environment but roughly what run time do you get out of a 8.5-9kg bottle?

Originally Posted by crump

thanks for the info, I already have a compressor fridge for touring but am looking for something bigger for week long fishing trips, especially the freezer bit.So more questions, how much gas do these babies chew, i know that is dependant on environment but roughly what run time do you get out of a 8.5-9kg bottle?

I have an Engel 25litre compressor (bloody good fridge ) and a 30 odd litre Primus, 3 way, which we bought to run on LPG when camping.

I ran it over Christmas, to keep extra booze cold (on 240v) and it ran like a charm

Like Caravan fridges, you have to ensure that they are level, to work properly.

Cheers,

Originally Posted by crump

thanks for the info, I already have a compressor fridge for touring but am looking for something bigger for week long fishing trips, especially the freezer bit.So more questions, how much gas do these babies chew, i know that is dependant on environment but roughly what run time do you get out of a 8.5-9kg bottle?

Crump

The typical 'consumption' in LPG terms is approx 16 - 20 gramms / hour

So taking the worst case senario 1 kg in approx 50 hours -

9kg bottle should last for 450 hours.

Or just over 18 days
Ladas