Tuesday, May 05, 2020 at 11:32
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It may be helpful to describe just how 'eutectic fridges' work and their advantages/disadvantages.
Firstly, bear in mind at all times just how any refrigeration works. After reducing the fridge chamber and its contents to the desired temperature, the sole function of any refrigeration system is to remove heat that enters the chamber in order to maintain the chosen low temperature. This heat enters through the insulation, warm air entry through opening the chamber, and the addition of warm commodities to the chamber.
In a 'conventional' fridge, the compressor runs intermittently to remove the entered heat that was gained from the above means. Consequently, the power to drive the compressor can come from a solar panel if the sun is shining, the vehicle alternator if the engine is running, or stored energy from a battery if the previous are not available.
In a 'eutectic fridge', which also has a similar compressor system, the stored energy comes from the eutectic medium which has been cooled by the solar or alternator. It does not require a battery to maintain the chamber temperature when electric sources are not available. To achieve this, the eutectic fridge has energy storage in the form of a volume of fluid that has been cooled below the 'phase transition point' when the external power was available. The eutectic fluid is in the form of a brine solution composed of water and typically sodium/calcium salts or glycol of specific ratio. Its significant feature is the 'transition phase' from frozen solid to thawed liquid where appreciable specific heat transfer takes place. The energy to cause this thawing is taken from the heat entering the chamber. Hence, they must be operated at a very low temperature set point to take advantage of the eutectic transition function.
So in essence, both types of refrigeration systems have a similar feature. They each store energy, one in an electric battery, the other in an eutectic solution. Each of them are required to remove the same heat energy entering the chamber. The eutectic cell adds weight, volume and cost to its fridge, the auxiliary battery adds weight, volume and cost to the conventional fridge. Each of them require similar generation of electrical energy. Each of them operate for a limited time before regeneration of the stored energy is required. The eutectic must always be operated at a low set point to embrace the phase transition function.
There may be some efficiency differences in the cyclic operation of the compressors but it would be minor. The major point of efficiency for both is always in the insulation value of the fridge chamber, and this adds volume to the cabinet. The compact storage and reliability of lithium batteries has increased the benefit of electrical storage and boosted the appeal of conventional compared to eutectic fridges.
As usual, it gets down to personal preference and the assessment of capital expenditure.
AnswerID:
631373
Follow Up By: Frank P (NSW) - Tuesday, May 05, 2020 at 16:45
Tuesday, May 05, 2020 at 16:45
Kimberley Kampers were selling Autofridges for quite a while as an option. Through our
Kimberley group I got to meet Autofridge's proprietor. He subsequently helped me with the refrigerant side of my water-cooled mod to my conventional fridge. In combination with lithium batteries that has delivered a very effective improvement in terms of fridge performance and power management.
FollowupID:
907380