Principle of operation
The principle of operation of an car refrigerator, in other words, the cooling method used in it.
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Thermoelectric (Peltier). Cooling using thermoelectric plates, so-called. Peltier elements. When current is passed through such a converter, one side of the plate is cooled, and the other side is heated. Thanks to this, in car refrigerators of this type, it is possible to implement not only cooling, but also heating (see "Operating modes"). Compared to compressor refrigerators, thermoelectric systems are much simpler, more reliable, more compact and cheaper. On the other hand, with higher power consumption, they have lower performance. And the efficiency of Peltier elements is not very high — in particular, they do not cool to a certain temperature, but to a certain number of degrees relative to the ambient temperature (usually 10 – 15 °C).
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Absorption. Absorption refrigerators are known as devices that can operate not only from electricity, but also from a gas cylinder. The principle of their operation is based on the absorption of ammonia by water and the heating of the water-ammonia solution with a heater; the heater can be either electric or gas. Accordingly, one of the main advantages of such models is independence from electricity. This is especially true when used outdoors, especially since the gas consumption is very low — for example, a 5-liter cylinder can last for almost 10 d
...ays of continuous operation. At the same time, in terms of speed and overall cooling efficiency, such models are noticeably superior to thermoelectric ones, although they are inferior to compressor ones. On the other hand, the design of the absorption car refrigerator is quite simple, and the noise level is low. The volume of such units can be quite impressive — up to 100 liters or more.
— Compressor. Similar models use the same principle of operation as conventional home refrigerators. The compressor "drives" the refrigerant through the refrigeration circuit between the evaporator and condenser; cooling occurs due to the evaporation of the refrigerant, then excess heat is discharged to the outside through the condenser heat exchanger. This principle of operation is considered the most effective: compressor car refrigerators very quickly gain operating temperature and perfectly cool the contents, it is quite possible to provide freezing in them, and the volume of such a unit can be almost any. On the other hand, compressor systems are quite complex and expensive, they do not tolerate shocks and shaking, and they also require a constant power supply, which can create inconvenience during long field trips.Max. cooling at
This parameter determines how many degrees the refrigerator is able to cool the product loaded into it relative to the ambient temperature. Let's say the maximum cooling for a particular refrigerator model is 20°C; at an air temperature of +30°C, a product with the same temperature is loaded into it. Thus, the final temperature of the product will be 30 – 20 = +10 °C. In addition, it should be noted that the final temperature cannot be lower than the minimum cooling temperature (see Minimum cooling temperature)
Min. cooling temperature
The minimum temperature to which the refrigerator is able to cool the product placed in it when operating in cooling mode. It should be taken into account that the minimum cooling temperature is not always achievable in fact: the actual cooling temperature depends on the ambient temperature and on the capacity of the refrigerator for maximum cooling (for more details on the calculation formula, see "Maximum cooling per (°C)"). However, this applies only to refrigerators that are not equipped with compressors (see Compressor);
compressor models are able to reach the minimum cooling temperature regardless of external conditions.
Сooling energy consumption
The power consumed by the refrigerator when operating in cooling mode. The greater this power, the more performant the refrigerator is, usually, and the less time it takes to cool the product. On the other hand, note that more power means more power consumption — which can be critical, for example, during long-term operation from a car battery (that is, when the car engine is turned off).
