Ingredients:

• A substantial piece of land that you are not too fond of. The excavation work will disturb your lot even if the excavator operator is careful.

• Creative thinking and problem-solving skills; you can't imagine how many small obstacles arise along the way when building your own sand battery.

• Patience (infinite).

• Sand. In our prototype, we used 24 m³ of sand.

• Insulation material. We used 16,000 liters of perlite, a ceramic fiber fabric that withstands very high temperatures, and a waterproof insulation layer that protects against moisture.

• A piping system where hot air circulates for heating the sand.

• An excavator. Plan on renting an excavator with an operator for at least three days unless you are significantly more efficient than we were.

• A pit, large enough to accommodate the sand battery. You want to minimize the hours for backfilling the sides of the pit. But you also don't want the pit to be too small to fit the sand battery. We tested this, and it is not recommended.

• Studs, plywood, and a lot of screws and staples.

• Heat-resistant and insulating tape (a lot).

• Avoid rain and windy weather when constructing the containers for sand and insulation materials. Otherwise, you'll have to do the job twice. Like we did.

• An electric heating system that can handle up to 800 °C.

• A fan system that circulates the hot air in the sand battery. It should withstand up to 800 °C.

• Sensors that measure the heat in the sand battery.

• Programming skills to construct an app that regulates the storage and extraction of heat in the sand battery.

• A well-developed ability to laugh at seemingly hopeless situations that sometimes arise and then leave them behind and move on.

More ingredients and a more detailed description of how to build your own sand battery will be published as we progress in the prototype work. We are also outlining how, in the future, we can offer our assistance in building sand batteries for individuals, housing cooperatives, and joint property associations. Perhaps even for schools and other public buildings as part of an emergency management plan.