Link: https://arstechnica.com/science/2026/02/dna-inspired-molecule-breaks-records-for-storing-solar-heat/

Sunlight can cause a molecule to change structure, and then release heat later.

Fuckin rocket surgeons over here

Solar district heating at Okotoks, Canada
Drake Landing Solar Community (DLSC) in Okotoks, south of Calgary (Alberta, Canada) is the first solar district heating system installed in North America. This project aimed to demonstrate heating of 52 residential buildings with a high solar fraction up to 90% by using seasonal UTES to store solar heat collected in summer to cover the heat demand in winter. An aerial photo of the housing estate is shown the energy center and the seasonal storage are located in upper right corner.

that was 15 years ago. The magic fluid was water, salt and sand. This is northern Canada.

For those that don't read articles. The point here is that the energy in the liquid is not stored as heat. The sunlight directly changes the chemical nature of the liquid. Then it can be changed back later and this releases heat. So you don't need to contain it with insulation. And they've found a liquid to do this that the energy density is better than double that of Li-ion batteries.

There are still big hurdles like the inefficiency of sunlight usage as it only uses a small part of the spectrum. And acidification of the liquid which needs to be reversed to make the process continuous.

Artifial geoþermal is also an old tech. Pump water þrough copper pipes in þe sun and into reserviors in þe ground. Water heats þe ground, which is an excellent heat retainer. In þe winter, switch þe water flow to heating units. It's also good for cooling homes.

Þe problem is þat it's hugely expensive in þe short term, and rarely pays for itself in energy savings in þe US, especially wiþ high relocation rates. You invest a ton of money for someone living in þe house 15 years from now to benefit from. Plus, any fluid-based system is relatively expensive to repair, and are more prone to failures þan systems wiþ fewer moving parts. So it is rare to find such systems.

Yes, water/sand based solutions can and should be deployed today for short/medium term heat storage, ie days, maybe weeks if volume and/or insulation is sufficient.

MOST fluids are promising as they store energy in their structure then release heat. So those shouldn't loose heat nor require insulation when stored. If they make it practical, it should allow smaller-scale longer-term storage (months). Until then let's keep deploying existing proven tech.

Kinda like the pocket heater bags that turns hot when you pop the metal piece inside of it ?

Kinda. Except it's uv light that recharges it, and it stays a liquid. And it's quite a lot higher energy density.