Introduction
When buying a refrigerator, you may come across two main technologies: the compressor refrigerator and the absorption refrigerator. Both cool, but in very different ways, with real consequences for energy consumption, noise, the power sources you can use, and price. This article explains how each one works and when to choose it, whether for the home, a caravan, or occasional use.
Compressor Refrigerators: How They Work
The compressor refrigerator is by far the most common in households. It relies on the vapour-compression cycle: an electric compressor pressurises a refrigerant, which condenses, then expands and evaporates inside the appliance while absorbing heat. This is the same technology described in our guide to the different types of refrigerators.
Advantages
- Energy efficiency: for the same amount of cooling, a compressor uses considerably less electricity than an absorption system.
- Cooling power: it reaches low temperatures quickly and copes well with high ambient heat.
- Regulation: the thermostat switches the compressor off and on, which keeps the internal temperature stable (ideally between 4 and 5 °C in the fridge compartment).
Disadvantages
- Noise: the compressor produces an intermittent hum when it kicks in, although inverter models have become very quiet. To dig deeper, see how many decibels for a quiet refrigerator.
- Power supply: it needs an electrical source (230 V mains, or 12 V for portable compressor coolers).
Absorption Refrigerators: How They Work
The absorption refrigerator uses neither a compressor nor any moving part. It is driven by a heat source (an electric heating element, a gas burner, sometimes recovered heat) that sustains a chemical cycle. The domestic version is based on the diffusion system developed by the Swedish engineers Baltzar von Platen and Carl Munters in 1928: it combines ammonia as the refrigerant, water as the absorbent, and hydrogen as an inert gas to balance the pressures. The absence of a compressor is what makes it almost silent.
Advantages
- Silence: with no moving parts, it makes practically no noise, which makes it ideal for a bedroom, a hotel minibar, or a boat.
- Flexible power sources: many caravan and motorhome models are so-called "three-way" units (230 V, 12 V and gas), useful off-grid. That is a real asset when you want to keep food cool without electricity.
Disadvantages
- Energy efficiency: an absorption system has a low efficiency (a coefficient of performance below 1), whereas a compressor comfortably exceeds 1. For the same cooling output, absorption therefore uses far more electricity.
- Sensitivity to heat: its cooling struggles as ambient temperature rises, and it takes longer to recover.
Consumption, Noise and Uses: The Comparison
In short, an absorption refrigerator trades efficiency for silence and flexibility of power source. On mains electricity, it uses noticeably more than a compressor of comparable size, which weighs on the bill for everyday home use. Running on a gas bottle, however, it becomes very handy where there is no electricity. The compressor, meanwhile, remains the champion of efficiency and of performance in hot conditions, at the cost of a slight operating noise.
For domestic use, the European energy label (the A to G scale, in force since March 2021 and adopted in Switzerland) applies to the compressor appliances sold in shops; comparing the stated annual consumption in kWh/year is the best benchmark. If you are mainly after a portable backup solution, it is worth also looking at other cooling options such as the Peltier module or even replacing a fridge temporarily with a passive cooler.
Conclusion
The choice depends above all on how you will use it. For the home, where the appliance runs continuously, the compressor refrigerator is almost always the better choice: more efficient, more powerful and cheaper to run. For camping, caravanning, a boat, or a bedroom where silence matters and where you want to be able to run on gas, the absorption refrigerator still makes sense. And if you are instead torn between an old appliance and a newer one, our guide on whether to repair or replace your fridge can help you decide. The absorption cycle is described in detail by Wikipedia (absorption refrigerator).