The rapid global shift to intermittent renewable energies requires viable utility-scale energy storage for uninterrupted power supply.

Hydropneumatic Isothermal Compressed Air Energy Storage (HICAES) uses a liquid inside an underground pressure vessel to accomplish isothermal air compression and expansion for energy storage and energy recovery. The pressure vessel is a hydraulic accumulator that provides for direct compression, expansion, and heat exchange, while using a fluid eliminates the need for adiabatic air compression and expansion during energy storage and recovery, making the process isothermal.  HICAES offers many advantages over Lithium-Ion batteries. 

HICAES can operate over a wide range of energy storage capacities and power response rates, making it suitable for residential, commercial, industrial, and grid-scale applications. HICAES is comprised of pumps, generators, and at least two underground vertical shafts of considerable size; one is for the pressure vessel, and the other is to store the fluid . 

HICAES is available in two technologically different forms.  One is "Hydro-Power Generator HICAES" that uses water with a high-head pump and generator, and the other is "Residential HICAES" that uses hydraulic fluid with a positive displacement pump and a hydraulic generator.  The technology can operate over a wide range of energy storage capacities and power response rates making it suitable for residential, commercial, industrial, and grid-scale applications.

HICAES is a SEITec Innovative Technology (www.SEITecinc.com).

This is a pressurized pumped-storage hydroelectric facility that works based on our patented isothermal gas compression and expansion principles in vertical underground vessels (US Patent No. US9787161B2).  Using our patented WaterSilo technology (US Patent No. US11028611B2), it constructs two vertical underground vessels; one is a pressure vessel (hydraulic accumulator) that powers a Power Unit with pressurized fluid, and the other is a fluid storage tank that receives the outflow from the generator and is equipped with a high-head pumps to re-pressurize the pressure vessel.  The technology enables energy storage and hydropower generation using highly efficient Isothermal Compressed Air Energy Storage (ICAES) and recovery.  

The slow rate of air compression/expansion and the large surface area of the vessel in contact with the ground result in a near-constant temperature (isothermal) process over the cycle.

Energy Recovery

Energy recovery is accomplished by pressurized water inside the vessel running a power unit to generate electricity.

Residential HICAES uses a high pressure pump, a power unit, an underground vertical hydraulic accumulator, and an underground vertical fluid storage vessel to enable Isothermal Compressed Gas Energy Storage.  The pressure vessel has a thick wall and is rated for the high pressure while the fluid storage vessel has a thin wall since it is under relatively low pressure.

The slow rate of air compression/expansion and the large surface area of the vessel in contact with the ground result in a near-constant temperature (isothermal) process over the cycle.

Energy recovery is accomplished by pressurized fluid inside the pressure vessel (hydraulic accumulator) running a the power unit to generate electricty.