A method for modifying a solar thermal power plant operating on conventional oil based technology into a hybrid solar thermal power plant includes: providing an oil-based solar thermal power plant, which includes a solar collection system with at least one radiation absorber tube containing a heat transfer oil to be heated by the solar collection system; providing a molten salts solar thermal power plant, which includes a solar collection system to heat a molten salts mixture; and coupling the respective plants such that the hybrid solar thermal power plant is configured to heat medium temperature steam generated by the oil based solar power plant by the molten salts mixture thereby producing high temperature steam and subsequently supplying it to a steam turbine to generate electricity.

A solar power system includes a solar energy collector that has at least one solar receiver that is operable to carry a working fluid and at least one solar reflector that is operable to direct solar energy towards the at least one solar receiver to heat the working fluid. The working fluid has a maximum predefined operational temperature up to which it can be heated. A first storage unit is connected to receive the working fluid from the at least one solar receiver, and a second storage unit is connected to provide the working fluid to the at least one solar receiver. A power block generates electricity using heat from the heated working fluid. A heater is operable to heat the working fluid to approximately the maximum predefined operational temperature.

A solar hybrid power plant comprises a combustion turbine generator, a steam power system, a solar thermal system, and an energy storage system. Heat from the solar thermal system, from the energy storage system, or from the solar thermal system and the energy storage system is used to generate steam in the steam power system. Heat from the combustion turbine generator exhaust gas may be used primarily for single phase heating of water or steam in the steam power system. Alternatively, heat from the combustion turbine generator exhaust gas may be used in parallel with the energy storage system and/or the solar thermal system to generate steam, and additionally to super heat steam. Both the combustion turbine generator and the steam power system may generate electricity.

Solar energy is collected and used for various industrial processes, such as oilfield applications, e.g. generating steam that is injected downhole, enabling enhanced oil recovery. Solar energy is indirectly collected using a heat transfer fluid in a solar collector, delivering heat to a heat exchanger that in turn delivers heat into oilfield feedwater, producing hotter water or steam. Solar energy is directly collected by directly generating steam with solar collectors, and then injecting the steam downhole. Solar energy is collected to preheat water that is then fed into fuel-fired steam generators that in turn produce steam for downhole injection. Solar energy is collected to produce electricity via a Rankine cycle turbine generator, and rejected heat warms feedwater for fuel-fired steam generators. Solar energy is collected (directly or indirectly) to deliver heat to a heater-treater, with optional fuel-fired additional heat generation.

To operate solar thermal technology economically, a cheap heat transfer fluid is used. To either completely spare or significantly reduce the energy-intensive auxiliary heating at night, a water tank is simply installed in the plant without a threat to the environment. With the water tank, the salt HTF is thinned by adding water when the solar heating is not in operation.

Energy storage systems are disclosed. The systems may store energy as heat in a high temperature liquid, and the heat may be converted to electricity by absorbing radiation emitted from the high temperature liquid via one or more photovoltaic devices when the high temperature liquid is transported through an array of conduits. Some aspects described herein relate to reducing deposition of sublimated material from the conduits onto the photovoltaic devices.

A heat exchanger (10) is disclosed for providing heat exchange between fluids (24, 25), such as in a solar power plant (1), wherein said heat exchanger (10) comprises a first pipe connector (13) and a second pipe connector (14), and a pipe bundle (17) extending between the first and second pipe connectors (13, 14), wherein said pipes (17a-17n) of the pipe bundle (17) are configured to guide a second fluid (25), wherein said pipe bundle (17) is connected to the first and second pipe connectors (13, 14) at pipe connection points (16) so the inside of the pipes (17a-17n) of the pipe bundle (17) is in fluid communication with the cavities (15) of the first and second pipe connector (13, 14), and wherein pipes (17a-17n) of the pipe bundle (17) are arranged next to each other and extend together between the pipe connectors (13, 14) in a meandering manner providing a plurality of crests (20a, 20b) on the pipes (17a-17n) between the pipe connectors (13, 14), and so that crests (20) of pipes (17a-17n) of the pipe bundle (17) are arranged to extend into recesses (21) provided by one or more crests (20) on other pipes (17a-17n) of the pipe bundle (17).

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.

A dispatchable storage combined cycle power plant comprises a topping cycle that combusts fuel to generate electricity and produce hot exhaust gases, a steam power system, a heat source other than the topping cycle, and a thermal energy storage system. Heat from the heat source, from the thermal energy storage system, or from the heat source and the thermal energy storage system is used to generate steam in the steam power system. Heat from the topping cycle may be used in series with or in parallel with the thermal energy storage system and/or the heat source to generate the steam, and additionally to super heat the steam.

A control method for optimizing generated power of a solar-aided coal-fired power system under off-design working conditions sets maximizing generated power without changing main steam flow rate as a control goal. A solar-coal feedwater flow distribution ratio is adjusted to adjust water flow rate heated by a solar heat collection system, so as to achieve the control goal. Control steps include reading relevant information; calculating the water flow rate range heated by the solar heat collection system, and an applicable solar-coal feedwater flow distribution ratio range; establishing a correspondence between the generated power and the solar-coal feedwater flow distribution ratio within this range; selecting a solar-coal feedwater flow distribution ratio corresponding to the maximum generated power; and adjusting the water flow rate entering the solar heat collection system to an optimized value. The present invention can flexibly control the solar-coal coupling and improve the economy.