The most common method for storing electricity on a bulk scale is currently pumped hydroelectric. This is comparatively expensive, has long build times, and a shortage of potential sites. Other methods include compressed air, thermal energy storage, and various battery technologies. For power generation, steam and gas turbine cycles largely dominate.
This UK company's new approach uses a patented condenser method to extract energy from the steam turbine exhaust and heat pumps it to temperatures suitable for additional energy extraction.
This provides dramatic efficiency increases on a wide range of energy storage and generation applications including thermal electric and hydrogen combustion, geothermal and bio-fuel generation and conventional power plants, reducing associated emissions and fuel consumption.
This new process uses a heat pumping condenser method, air compressors with compression heat recovery, and air expander turbines. The air compressor and expanders can be arranged in brayton cycles where air compression heat is recovered to pre-heat the steam turbine flow. Where air and thermal storage are practicable, the compressor and turbines can separate as with adiabatic compressed air systems, the air being stored using off peak electricity and compression heat extracted for thermal storage. The main advantage is that the air compressor no longer presents a peak time energy drain, increasing peak power output.
The condenser heat exchanger tubes use the airflow to absorb latent heat energy from the steam turbine exhaust and also to provide the air turbine expansion heat. These functions are enhanced by staged venturi effect nozzles on the air tubes. As the air accelerates through the tubes it is adiabatically cooled, increasing the temperature gradient between the air and steam exhaust. Since air is accelerated up to supersonic velocities, accelerations are performed in stages with intermediate heat absorbing sections to control the heat absorption rate and prevent steam freezing to the tube. When the air leaves the condenser, it is slowed in final nozzle stages, causing significant re-pressurisation heat between 200-240°C which is then used for energetic air turbine expansion.
Efficiency is expected at around 80% based on data for the component cycles. These high efficiency levels can be achieved by limiting the most significant points where energy is lost – the air compression heat and the latent condensing energy are both recovered in a useable state. Installation costs for thermal electric energy storage enhanced by this method will be significantly less than the competing adiabatic compressed air whose efficiency it now matches, providing highly competitive net payback and estimated return on investments, particularly where existing power station equipment is repurposed. It also provides enhanced potential for wide ranges of other power generation applications.
UK company is looking for partners from the power industry and seeking companies that can help bring this solution to the market.
UK company is seeking a joint venture agreement or licencing agreement with power industry companies and also seeking financial agreements with investors.
