Of course... if you have converted to LPG you could have a go at an LPG powered fridge!
Well, maybe. I'm not sure how they work!
PAGING SIMON!!!! Simon to the LPG Phone please :)
Thats usually called a caravan on the towbar
Possible... Good points are gas consumption is economical, work better (when level, i.e. not parked on a steep hill) than a thermo-electric fridge, no flattening of batteries to worry about. Bad points are you've got a flame inside the car, it would need an exhaust flu to prevent gassing vehicle occupants (with engine off / ventilation off) so that's a hole in the roof or side of the car, usually need to be level to work properly (though some fridges are much more forgiving than others in this respect), the flu's can lead to the flame being blown out in wind/while driving (some setups seem much better than others in this respect too). Best practice is to fit the fridge with not only an exhaust flu but also it's own intake air setup (hole in the floor under the flame), the LPG tank would need modding to have a vapour take-off fitted to run to a manual shut off valve to the regulator to the fridge.
Would usually be a caravan type fridge but freestanding 240/12v and gas fridges are available (I've always had one). The freestanding type aren't meant to be ran on gas in confined spaces, no easy way of connecting to a flu.
I do fit vapour take-offs on autogas tanks, as part of the setup I insist that I supply and fit the gate valve and regulator (both external) running a length of pipe from the regulator to where the customer needs (usually the gas inlet for their campervan). On most installs I fit the gate valve so it can be accessed by reaching a hand under the vehicle. To fit the vapour take-off (on external autogas tank) I drill a 3mm hole in the top of the tank, cut a 'hidden filler' boss in half (leaves a steel hexagonal pipe with 8mm pipe compression fitting, total length about 20mm), grind the hex down so it's round, weld it onto the tank over the hole, fit a cut down/shortened 90degree fitting into the compression fitting and run pipe (copper or Faro) from this to the gate valve which is fitted directly onto the regulator. I shouldn't really be modding/welding tanks but it is safe when the tank is external, could be safe internal if I came up with a way of fitting a gas tight housing around the mod (wouldn't be too difficult). This way there's only a 3mm hole in the tank (so if the worst happened and the fitting came off it wouldn't be toooo bad) and since the internal area of the fitting is only about 8mm diameter (50sq mm / 0.1sq inch) there'll only be around 30pounds pushing against the fitting/weld if the tank sees 20bar pressure (reckon the weld would be good for about a ton).
Recently bought a thermo-electric heat pump type fridge from Halfords to slot between the front seats on long trips, it will keep stuff cool if it's cool when it goes in but takes an age to pull temperature down if stuff isn't cold when put in. Will only cool to about 15degC below ambient temp, OK in an AC cooled car and only draws 6Amps at 12v. An electric compressor type would be a lot better, or would be possible to tap into AC lines and fit another evap in an enclosed box to make a very powerful fridge that would obviously only work with the engine running... I thought about doing this when I recently had AC problems and had to change my engine, would have been the ideal time to fit it, but in the end I just wanted to get the car running again.