Heat 2 Power:
New Thermo Storage Technology []

Competitor product 1: Concrete storage

The storage consists of a bundle of horizontally arranged heat exchanger cylinders made of special concrete with a diameter of approx. 25 cm. Inside each cylinder are 2 parallel U-shaped steel tubes. To extract the stored heat, the direction of flow is reversed. A 20ft module can store up to 1.5 MWh.

Advantages:

• Simple modular construction

Disadvantages:

• Limited temperature range up to 400°C, therefore mainly intended for generating process heat
• To generate electricity, it is necessary to decouple heat to a second medium
• No continuous operation, but change between "in - out"
• Heat in the returning fluid flow cannot be used to generate electricity

Competitor product 2: lava rock storage

A container houses a bed of lava rock through which hot air flows to heat it up. To extract the stored heat, the direction of flow is reversed and switched to a circuit with a steam generation system with a downstream turbine.

Manufacturer information: The stored heat can be used to generate 1.5 MW of electrical energy over a period of 24 hours via a steam turbine.

Advantages:

• Cheap storage material
• Easily scalable
• Underground installation possible

Disadvantages:

• Relatively small usable temperature range
• Gas seeks the path of least flow resistance, hence dead spaces and uneven temperature distribution
• To generate electricity, it is necessary to decouple heat to a second medium
• No continuous operation, but change between "in - out"
• Heat in the returning fluid flow cannot be used to generate electricity
• Large volume
• No constant energy output to the subsequent heat engine, since the temperature in the storage tank continuously decreases when discharging
• Dust (abrasion from bulk material) in the circulating air circuit, therefore a (high-temperature) filter is required

Competitive product 3: Metal body

Electricity that is fed in is converted into heat via a resistance heater, which then reaches the storage core made of steel elements via a gas circuit. The stored heat reaches a heat exchanger via the same gas circuit, which feeds out process heat or process steam.

Advantages:

• High storage density
• Expensive storage material that retains its value
• Modular construction

Disadvantages:

• Limited temperature range, therefore mainly usable as heat supplier. Larger systems can also produce electricity.
• To generate electricity, it is necessary to decouple heat to a second medium
• Heat in the returning fluid flow cannot be used to generate electricity
• No constant energy output to the subsequent heat engine, since the temperature in the storage tank continuously decreases when discharging

Competitor product 4: Granulate storage

Hot air flows through the special granules and heats up to 1300°C. To extract the stored heat, the direction of flow is reversed.

Advantages:

• High maximum storage temperature
• Modular structure
• High energy density

Disadvantages:

• Gas seeks the path of least flow resistance, hence dead spaces and uneven temperature distribution
• To generate electricity, it is necessary to decouple heat to a second medium
• No continuous operation, but change between "in - out"
• No constant energy output to the subsequent heat engine, since the temperature in the storage tank continuously decreases when discharging
• Dust (abrasion from bulk material) in the circulating air circuit, therefore a (high-temperature) filter is required

Competitor product 5: Ceramic shaped bricks

Electrical resistance heaters are located in a structured accumulation of ceramic blocks and heat them up by radiation. To extract the stored heat, there is a circulating air circuit that is used to generate steam for a turbine.

Advantages:

• Very high usable temperature range
• Continuous operation (simultaneous loading and unloading) possible

Disadvantages:

• To generate electricity, it is necessary to decouple heat to a second medium
• Electrical heating inside the storage tank, therefore no use of waste heat as heat source possible
• High flow resistance
• Complex structure
• Constant energy delivery to the subsequent heat engine is only possible with a high level of control effort or parallel reheating

Other competing products

Numerous other comparable technologies .....

Their main common mistake: First select the storage material, then determine the layout of the system

Disadvantages:

The principles and their disadvantages follow the same pattern as those already mentioned above...

Note: Subsequent turbines require at least 300°C to operate. Only heat provided by the storage between 300°C and T_max can be used to generate electricity. Heat below 300°C can only be used as process heat. The usable proportion of stored heat is therefore small, and the efficiencies of existing technologies are generally poor. This is why this technology is not yet widely used.

The claimed efficiencies of the actual suppliers refer to electricity + heat, which is just a marketing trick. In addition, these tricky calculations do not take into account that the heat supply is cyclical and not continuous.