A group of Swiss researchers claim to have developed a process that can capture heat during summer and then later use it during winters. Additionally the captured energy can be physically transported anywhere it may be needed.
The new system uses concentrated sodium hydroxide (NaOH) as the thermal storage medium, and a collection of largely off-the-shelf components to capture, convert, and release heat energy on demand.
To achieve this, water is poured onto dry sodium hydroxide and an exothermic reaction ensues, where the chemical energy contained in the NaOH is released as heat. Since NaOH is extremely hygroscopic, more heat is produced from water condensing from vapour in the air and the sodium hydroxide solution is heated even further. This way, more heat is liberated by adding water.
Similarlry, if heat energy collected from the sun or any other source is fed into the NaOH solution diluted with water (H2O), the moisture quickly evaporates and the solution becomes more concentrated. This concentrated mixture can then be kept stored for many months, even years, until the heat is once again liberated when the NaOH is exposed to water again. The solution can also be easily transported in tanks to other areas where heat energy is needed.
The storage medium is a viscous liquid composed of a 50 per cent NaOH solution that is made to trickle along in a spiral pipe, where it soaks up water vapour along the way and then conveys the generated heat into the pipe. The heat is then free to radiate, convect, and conduct into the area requiring warmth.
The reverse of this process – passing heat through the medium to store energy has also been demonstrated in the system. The moisture from the NaOH solution evaporates when heat is applied, which is then drained off and condensed.