The invention relates to a method and to a steam power plant, wherein solar energy can be very flexibly and very efficiently coupled into the water steam circuit of the steam power plant.

Atmospheric solar energy recovery. At least one example is a method comprising: warming a first fluid from heat in atmospheric air, the warming creates an increase in volume of the first fluid; moving a working piston by the increase in volume of the first fluid during the warming, the movement to a first position; holding the working piston in the first position to create a first fixed working volume; exchanging heat in first fluid with a second fluid while the working piston is held in the first position, thereby reducing pressure of the first fluid below atmospheric pressure; and then releasing the working piston; moving the working piston by a first differential pressure between atmospheric pressure and pressure of the first fluid; and converting movement of the working piston caused by the first differential pressure into usable work.

A method of operating a solar energy plant and a solar plant are disclosed. Thermal energy produced in the plant is used to heat a first volume of water and charge a hot store in the plant. Electricity produced in the plant operates a heat engine or other device, such as a refrigeration unit, to extract heat and consequently cool a second volume of water and charge a cold store. As desired, energy is transferred from the hot store to a heat engine and energy is transferred from the heat engine to the cold store to operate the heat engine to produce power in the plant.

A temperature control system includes: a compressor, a condenser, an expansion valve, and an evaporator all connected in series to form a refrigerant circuit. The system includes an electricity generating arrangement fluidly connected to the refrigerant circuit between the compressor and one of the condenser and the evaporator, the electricity generating arrangement comprising a solar thermal collector adapted to heat refrigerant leaving the compressor, and a fluid driven electricity generator adapted to receive refrigerant heated by the solar thermal collector.

Electrical energy storage and discharge system for storing electrical energy as thermal energy includes a heat pump cycle with first working fluid, a water steam cycle with second working fluid, a first thermal storage system with first thermal fluid, a second thermal storage system with second thermal fluid, an electrical heater member and a power regulating member, fluidly connected to each other. The system includes fluidly connected first cold and hot storage tanks, and the system includes fluidly connected second cold and hot storage tanks. The electrical heater is operably connected to the system between the tanks. The power regulating member is electrically connected to one or more electrical sources to regulate excess electrical energy, partially, to the electrical heater, and partially, to the heat pump cycle.

A method of operating a solar energy plant and a solar plant are disclosed. Thermal energy produced in the plant is used to heat a first volume of water and charge a hot store in the plant. Electricity produced in the plant operates a heat engine or other device, such as a refrigeration unit, to extract heat and consequently cool a second volume of water and charge a cold store. As desired, energy is transferred from the hot store to a heat engine and energy is transferred from the heat engine to the cold store to operate the heat engine to produce power in the plant.

A method of operating a solar energy plant and a solar plant are disclosed. Thermal energy produced in the plant is used to heat a first volume of water and charge a hot store in the plant. Electricity produced in the plant operates a heat engine or other device, such as a refrigeration unit, to extract heat and consequently cool a second volume of water and charge a cold store. As desired, energy is transferred from the hot store to a heat engine and energy is transferred from the heat engine to the cold store to operate the heat engine to produce power in the plant.