Absorption Cooling

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Build In & Portable Absorption Refrigeration Products
Refrigeration temperature +7 degrees C up to 32 degrees below ambient
Freezing capability ** -10 degrees

How does this refrigeration principle work?
A concentrated ammonia solution is heated in a boiler & driven off as vapour, The pressurised ammonia gas is then liquefied in a condenser. Supplied with hydrogen, it evaporates & extracts heat from the storage container. The ammonia gas then enters the absorber where it is reabsorbed in a weak solution of ammonia. Finally the saturated solution flows back to the boiler where the whole cycle starts again. The ammonia solution can be heated by three optional energy sources 12vdc, 230vAC, butane or propane gas.

Are they classed as a refrigerators?
Yes, this is a form of refrigeration & freezing

Can I use the cooler as a portable freezer?
Yes, please refer to the manufacturers instructions, Absorption refrigerators offer ** star -10 deep freezing. This enables you to keep ** rated produce for a period of two weeks.

How long do they take to get cool?
For +7 degree C refrigeration, approximately 30-40 minutes depending on the ambient temperature. ** -10 degree C freezing, approximately 1hr.

What cooling performance can I expect from my Absorption refrigerator?
7 degrees refrigerator. ** -10 deep freezing.

How do I choose the correct refrigerator or cool box for my holiday or requirements?
It is important to consider the type of climate you’ll be in, while using your portable cooler. 

Thermoelectric and absorption coolers will cool between 18–30 °C below the ambient temperature. Clearly, this may not be adequate if you are travelling in a region where temperatures reach 30 °C or more.

And so in hot regions, Dometic recommend using a compressor cooler. As shown in the table below, the cooling performance is so powerful that it can deep-freeze in even the hottest ambient temperatures:

Cooling technology

Outside temperature

Internal temperature achieved


40 °C

22 °C to 10 °C (depending on model)


40 °C

20 °C to 10 °C (depending on model)


40 °C

Preset temperature within range: 10 °C down to –22 °C (depending on model)

How do I calculate the battery consumption of my cool box?
An absorption refrigerator can draw between 80 to 170 watts on 12vdc, depending on the model. Divide the watts by the supply voltage (12vdc). (see example)

80 watts / 12v = 6.66 Ahrs per hr (average car battery size 60 to 70Ahrs, you should expect 60% of this power to be available).

Can I leave the cool box on in my vehicle if the vehicle engine is switched off?
Yes, an absorption refrigerators can be operated on the vehicles 12v battery, depending on the model (follow manufacturers instructions). Absorption 12v battery consumption must be observed, & vehicle DC cable thickness must comply with manufacturers recommendation.

Can I operate the refrigerator/cooler at any angle?
Absorption refrigerators operate up to a maximum tilt angle of 3 degrees. They should not be operated or stored on their side or upside down, this will effect the ammonia mixture inside the refrigerator & the cooling performance.

What ventilation do I need to allow?
It is imperative that the manufacturers guidelines are followed thoroughly in respect of ventilation. Portable absorption refrigerators should not be run on gas inside a vehicle or caravan or whilst sleeping in a tent. It is prohibited to operate an absorption refrigerator on gas on a marine vessel.

Cabinet refrigerators to be operated on gas, must be installed by a qualified refrigeration engineer. Specific vents must be installed to extract heat & fumes generated by the operation of the refrigerator on gas. These vents are fitted to the side of the vehicle so that heat & fumes can be exhausted to the outside.

How do I calculate the capacity of the cool box?
29 Litres = 1 cubic ft (the average household refrigerator is 4 cubic ft or 90Ltrs).

Which models include a thermostat?
All absorption refrigerators have built in thermostats.

Can I extend the 12v power cable?
Yes, please follow the manufacturers guidelines in the owners manuals, in respect of cable lengths & thicknesses over distance to avoid power loss.