Liquid Air

I had previously stated my ideas on “Robotic Highway”, “Wind Farm Construction Using VTOL Bases” and “The World Autonomous Air Cargo Way”. They all required autonomous robots recharging their batteries from wind turbines. There is a very big problem with this idea. That is the battery and to a certain extend electric motors and power electronics. In terms of energy storage capacity; nuclear has the highest energy density, then comes the chemical energy (combustion), then comes the phase change and the least dense is the battery.

After making some research, I found out that liquified air is the most advantageous energy storage system for autonomous robots. At the moment everybody is focused on the replacement for gasoline or the levelling of renewable power generation. Liquid air may not be a perfect solution for them. However, it is a perfect energy storage solution for autonomous robots. Here are some of the advantages:

- It has higher energy density then current batteries.

- It doesn’t require exported chemicals like batteries.

- Liquid air tanks have much longer lifecycle than the batteries which pose environmental hazard at the end of their economic life. Recycling them is also expensive and non-environment friendly (chemicals and energy used in the process).

- Liquid air can be directly converted to mechanical work. On the other hand, fuel cells require bulky and expensive fuel cells and then electric motors to convert the energy stored in a fuel to mechanical work. Combustion engines have a clear win there however fuel is an exported commodity and needs to be transported to the consumption site.

- Liquid air can be directly produced by the wind turbines using mostly mechanical parts (no electric motors). The air compressor and the chiller can be directly driven by the wind power. Negating the need for expensive electric motors for generation and compression. Additionally, negating the need for exported expensive power electronics to control the motors. The process would still require some electric, but it would be for low power electronics.

- The wind concentrator design I had proposed earlier, would be an ideal liquid air generator. The concentrated wind at the bottom would directly drive the air compressor and the chiller. The air leaving the turbine would be used to cool the compressors without a need for cooler fans.

- The liquid air would decrease the cost of the robots as well by reducing the need for expensive electric motors and their control electronics. The liquid air powered engines would be used to do the mechanical work.

- Autonomous flying bots would also benefit from the simple liquid air powered gas propulsion system. This would generate more thrust than the electric propeller powered drones. This is important during takeoff and landing. Additionally, liquid air is consumable. Therefore, the plane would lose weight as it flies unlike the battery powered drones that have constant weight of batteries.