Extra heat in a closed cycle power generation system, such as a reversible closed Brayton cycle system, may be dissipated between discharge and charge cycles. An extra cooling heat exchanger may be added on the discharge cycle and disposed between a cold side heat exchanger and a compressor inlet. Additionally or alternatively, a cold thermal storage medium passing through the cold side heat exchanger may be allowed to heat up to a higher temperature during the discharge cycle than is needed on input to the charge cycle and the excess heat then dissipated to the atmosphere.

Systems and methods relating to use of external air for inventory control of a closed thermodynamic cycle system or energy storage system, such as a reversible Brayton cycle system, are disclosed. A method may involve, in a closed cycle system operating in a power generation mode, circulating a working fluid may through a closed cycle fluid path. The closed cycle fluid path may include a high pressure leg and a low pressure leg. The method may further involve in response to a demand for increased power generation, compressing and dehumidifying environmental air. And the method may involve injecting the compressed and dehumidified environmental air into the low pressure leg.

The disclosure provides a heat pump cycle that allows for an improved matching of the T(Q) slopes of the heat pump cycle. More particularly, in the heat pump cycle, the high temperature heat exchange is separated into two stages. Furthermore, a portion of the working fluid that was cooled in the first stage, is further cooled by expansion before being mixed with a heated working fluid for input to the recuperating heat exchanger.

The disclosure provides a heat pump cycle that allows for an improved matching of the T(Q) slopes of the heat pump cycle. More particularly, in the heat pump cycle, the high temperature heat exchange is separated into two stages. Furthermore, a portion of the working fluid that was cooled in the first stage, is further cooled by expansion before being mixed with a heated working fluid for input to the recuperating heat exchanger.

Hydrogen boilers with no measurable NOx emissions. In some versions the fuel is a ratio of already mixed hydrogen and oxygen, ratio of pre-mixed hydrogen and oxygen, or the fuel comprises hydrogen and the burner also contains a separate nozzle for introducing a ratio of oxygen. In some versions, these ratios are stoichiometric between hydrogen oxygen. Some versions show burner systems that monitor the combustion process, which is a condensing process, and have hydrogen oxygen pilots and ultraviolet flame detectors. These hydrogen boilers can supply all the process steam needed by a system or can supply part of the process steam needed by a system.

Systems and methods for variable pressure inventory control of a closed thermodynamic cycle power generation system or energy storage system, such as a reversible Brayton cycle system, with at least a high pressure tank and an intermediate pressure tank are disclosed. Operational parameters of the system such as working fluid pressure, turbine torque, turbine RPM, generator torque, generator RPM, and current, voltage, phase, frequency, and/or quantity of electrical power generated and/or distributed by the generator may be the basis for controlling a quantity of working fluid that circulates through a closed cycle fluid path of the system.

The present invention provides a solar energy collecting and converting system comprising a plurality of segmented reflective elements such as mirrors forming a trough shape structure. These reflective elements are attached to the glass top of a metal box. The solar cells are placed at the bottom of the box and heat sinks are placed underneath the solar cells. Further, the segmented reflective mirrors are attached to a rod at the bottom for additional support. In a variation of the system, the solar cells are replaced with an insulated container comprising light absorbing material at the bottom of the panel. A glass window on the top of insulated container lets the solar light pass through and heat the light absorbing material. The small size of the window does not let the heat radiate from the insulated container through the window and improves the performance of the whole system.

Biomass (e.g., plant biomass, animal biomass, and municipal waste biomass) is processed to produce useful products, such as fuels. For example, systems are described that can use feedstock materials, such as cellulosic and/or lignocellulosic materials, to produce ethanol and/or butanol, e.g., by fermentation.

Biomass (e.g., plant biomass, animal biomass, and municipal waste biomass) is processed to produce useful products, such as fuels. For example, systems are described that can use feedstock materials, such as cellulosic and/or lignocellulosic materials, to produce ethanol and/or butanol, e.g., by fermentation.

Heat storage devices suitable for storing solar energy, and associated systems and methods are disclosed. A representative system includes a storage housing that contains a working fluid. A working fluid inlet pipe is coupled to the storage housing. A plurality of concrete plates are positioned in the housing, with the adjacent plates at least partially forming individual flow passages. A working fluid outlet pipe is coupled to the housing. A controller maintains a predominantly laminar flow of the working fluid in the flow passages. In some embodiments, the working fluid can be thermal oil having a boiling temperature of 300 C. or higher.