What is the feasibility of submarine's salt-free water softener technology?

Not very feasible.

This submarine product is actually the OEM product of Swiss SAT (Swiss Aqua Technologies) company. The address in official website is https://swatec.ch/zh., and the product name is IPS KalyxX. The descaling principle is to use the patented technology of turbulent polarization (TGP).

Let water flow through several groups of turbine electrodes made of different metals to generate a potential difference of about 0.8~ 1.8V, and generate eddy current. Then, such a device can convert calcite, which is easy to generate hard scale in water, into soft aragonite (both of which are homogeneous polymorphs of calcium carbonate), which is easy to be carried away by the current.

It can gradually soften and wash away the scale in the tap water pipeline within half a month to one month, reduce and prevent the accumulation of 76.3% scale, and its working life is at least 10 year.

In a word, the scale is softened by patented technology and is not easy to deposit. It still sounds mysterious.

I found that the literature shows that most of the scale in the pipeline is indeed formed by calcite. Therefore, it is feasible to convert calcite into aragonite. The difficulty is that aragonite is unstable and easily converted into calcite. However, it is difficult to convert calcite into aragonite, which generally requires low temperature and high pressure environment.

The patented TGP technology of Swiss company is to solve this problem, and the related principle is only explained in official website. Those who are interested can study it.

There are two commonly used water softener technologies. One is to remove calcium and magnesium ions from water with ion exchange resin to reduce the hardness of water. The other is nanocrystalline TAC technology, that is, template-assisted crystallization.

Using the high energy generated by nanocrystals, the free calcium, magnesium and bicarbonate ions in water are wrapped into nano-scale crystals, thus preventing the free ions from generating scale. Compared with tap water, soft water tastes and feels very obvious. Soft water has high oxygen content and low hardness, which can effectively prevent lithiasis, reduce the burden on heart and kidney, and is beneficial to health.

The above contents refer to Baidu Encyclopedia-Water softener.