Testing different types of sand batteries.. Results of testing I have done.

My progress and videos I have gained info from:

Overview of the sand battery:
1752 A DIY Sand Battery - The Theory, Practice And Use
https://www.youtube.com/watch?v=Icai6OOIh2M

Using the waste heat of a Diesel heater:
DIY Vevor Diesel Stove with Free Energy Sand Battery
https://youtu.be/x3VDCuyRJqw

Sand heat storage fireplaceㅣCleaning the fireplace
https://youtu.be/8XMOXftD_Ik

Isec solar cooker build:
https://www.youtube.com/watch?v=YX1SGK7gTg8

Someone who is doing a similar build as mine:
https://youtube.com/shorts/I5CHVMwNlys

3 ways to contain heat.
https://www.wtamu.edu/~cbaird/sq/2014/07/10/what-makes-heat-rise/

My permies thread on my progress on sand battery:

https://permies.com/t/206700/Sand-battery-thermal-mass-proto