There are basically three types of cooling systems used in fridges. Domestic fridges and freezers use a mechanical compressor. These are by far the most efficient and of course usually mains powered. You can get specialised fridges that use 12V compressors quite popular for motor homes, and boats, where a there's a greater availability of 12V power.
Caravan fridges typically use a process called absorption. These are driven by a small heat source, and can be gas, mains or even 12V (when power is supplied by the tow vehicle) These are less efficient, and are more sensitive to the ambient temperature, They often have limited cooling capacity in the hottest weather, but better than peltier units in group three.
The third type are the Thermoelectic which use a Peltier chip module. These need 12V dc power, and have a low electrical efficiency, and a far more limited cooling capacity and can they usually have a built in fan to circulate the air across its chip, which can be quite noisy. They often can only create 15 to 20C temperature drop, so in hot weather they may not run cold enough for long term safe storage.
If you are long term seasonally pitched with mains power, you might be tempted to look at a mains powered domestic fridge. Relatively cheap, (almost anything designed for the "leisure" market has a higher price) so if you intend to run of grid then you would need to look at other alternatives.
But as Clive has suggested, the temperature in an awning can be quite extreme, not only hot but also cold so you need to look for a fridge with a wide ambient temperature operating range - check the specification.