Like normal refrigerators but smaller
Mini Refrigerators come in different sizes and configurations – from the smallest bar or hotel room fridges to small fridge freezer combos, ranging in size up to 5 cu ft.
As mentioned, aside from hotel rooms, mini refrigerators are used as dorm fridges, beverage coolers or bar refrigerators, in small apartments or as outdoor units.
Ever wondered why some mini refrigerators are completely silent when running (usually in hotel rooms) while other refrigerators give out the “normal” compressor noises? This is because the silent fridges do not have a compressor or fan! They use the so called adiabatic cooling principle, where instead of compressor, a heat source is needed. Heat can come from electricity – 110V AC in hotel room fridges, 12V DC in car, RV and camping fridges – or propane in camping fridges.
Peltier coolers can be silent too (they do not have a compressor also), their fans are the only source of noise. Peltier based fridges are not considered to be mini refrigerators, they fit into portable / car cooler category.