A method for converting thermal energy into mechanical energy in a thermodynamic cycle includes placing a thermal energy source in thermal communication with a heat exchanger arranged in a working fluid circuit containing a working fluid (e.g., sc-CO2) and having a high pressure side and a low pressure side. The method also includes regulating an amount of working fluid within the working fluid circuit via a mass management system having a working fluid vessel, pumping the working fluid through the working fluid circuit, and expanding the working fluid to generate mechanical energy. The method further includes directing the working fluid away from the expander through the working fluid circuit, controlling a flow of the working fluid in a supercritical state from the high pressure side to the working fluid vessel, and controlling a flow of the working fluid from the working fluid vessel to the low pressure side.

An energy system includes a turbine flue heat exchanger feeding a storage tank arranged to deliver water on a high temperature (90° C.) line to supply circuits. A heat pump and storage tank are arranged to deliver lower temperature (45° C.) water on a low temperature line to the supply circuits. A number of the supply circuits are each arranged to receive high temperature water, receive low temperature water, and use these flows to deliver a process water supply at a desired high, low or intermediate temperature (65° C.). In some each supply circuits the blending is controlled by control of a low temperature line pump according to temperature of the process outlet. The low temperature tank is supplied by a heat pump the inlet of which is fed by a heat recovery heat exchanger which recovers waste heat from a plant, and so it is more efficient than if it received cold water. Electrical energy for the heat pump is at least partly supplied by the high temperature heater gas turbine. Overall, the system has excellent energy efficiency due to the manner in which waste heat is utilized, improved efficiency of a heat pump, and real time control of the high and low water lines.

There are various source of heat energy. Amongst the various sources Solar energy, waste heat form garbage, waste heat from transformers, waste heat from chemical reactions, waste heat from plant and machinery, heat from geo-thermal or the vast heat energy lying in the seas and oceans are some of the major ones which are free and unused. Apart from these, we can also produce heat energy from fuels like fossil fuels, hydrogen gas, forest products etc. A lot of heat energy is being wasted and though converted to mechanical or electric energy it is not that efficient. However, using the evaporation or sublimation and condensation process brought about through difference in temperature and the use of buoyancy factor to increase the efficiency of the energy production, the heat energy can be converted to mechanical or electrical energy in excess of hundred percent. Moreover, heat energy obtained from hydrolysis of some chemicals like salts or hydroxides and their dehydration for reuse or the heat stored as latent heat on melting of salts can be utilized for huge storage of energy for some months or more and use it through this invention method. The energy lying in the water under the oceans during winter can be easily utilized for production of huge energy when there are very low (freezing) temperatures on the surface of the earth.

A system includes a heat pump including a system for conveying a refrigerant fluid between two heat exchangers, the refrigerant fluid circulating through a closed circuit; at least two heat exchangers, at least one of the first and second heat exchangers including a plurality of energy storage devices collecting a portion of the energy of the refrigerant fluid or of a secondary fluid; a system for conveying the refrigerant fluid intended to receive or transmit a given amount of energy through the plurality of energy storage devices, and a system for conveying a secondary fluid intended to receive or transmit a given amount of energy through the plurality of energy storage devices.

An installation for producing electricity and heat, comprising a gas turbine unit, a photovoltaic unit and a solar thermal unit, and being configured for switching between: a first operation mode, in which the gas turbine unit produces said electricity and said heat, a second operation mode, in which the gas turbine unit produces only part of said electricity and the photovoltaic unit produces a rest of said electricity, and in which the solar thermal unit either produces a rest of said heat or provides heat to the gas turbine unit, and a third operation mode, in which said electricity and said heat are produced by the photovoltaic unit, the solar thermal unit, and optionally one or several steam turbines of the gas turbine unit.