A method for testing an overspeed protection apparatus of a single-shaft system that includes: a) operating the system at nominal speed and under electrical load, wherein the load is selected to be low enough that, after dropping the load, the speed of the system rises such that the speed remains below steam turbine threshold speed lower than gas turbine threshold speed, such that first overspeed protection is triggered when the speed of the steam turbine reaches the steam turbine threshold speed, and second overspeed protection is triggered when the speed of the gas turbine reaches the gas turbine threshold speed; b) dropping the load; c) increasing the mass flow of the steam introduced into the steam turbine and/or of the fuel introduced into the gas turbine such that the speed of the steam turbine reaches the steam turbine threshold speed; d) testing whether the first overspeed protection is triggered.

A method for testing an overspeed protection apparatus of a single-shaft system that includes: a) operating the system at nominal speed and under electrical load, wherein the load is selected to be low enough that, after dropping the load, the speed of the system rises such that the speed remains below steam turbine threshold speed lower than gas turbine threshold speed, such that first overspeed protection is triggered when the speed of the steam turbine reaches the steam turbine threshold speed, and second overspeed protection is triggered when the speed of the gas turbine reaches the gas turbine threshold speed; b) dropping the load; c) increasing the mass flow of the steam introduced into the steam turbine and/or of the fuel introduced into the gas turbine such that the speed of the steam turbine reaches the steam turbine threshold speed; d) testing whether the first overspeed protection is triggered.

A waste heat recovery system including a drive unit, the drive unit having a drive shaft, a compressor, the compressor operably coupled to the drive shaft, wherein operation of the drive unit drives the compressor, and a waste heat recovery cycle, the waste heat recovery cycle coupled to the drive unit and the compressor, wherein a waste heat of the drive unit powers the waste heat recovery cycle, such that the waste heat recovery cycle transmits a mechanical power to the compressor, is provided. Furthermore, an associated method is also provided.

Systems and methods for controlling a heat engine system are provided. One method includes initiating flow of a working fluid through a working fluid circuit having a high pressure side and a low pressure side by controlling a pump to pressurize and circulate the working fluid through the working fluid circuit and determining a configuration of the working fluid circuit by determining which of a plurality of waste heat exchangers and which of a plurality of recuperators to position in the high pressure side of the working fluid circuit. The method also includes determining, based on the determined configuration of the working fluid circuit, for each of a plurality of valves, whether to position each respective valve in an opened position, a closed position, or a partially opened position and actuating each of the plurality of valves to the determined opened position, closed position, or partially opened position.

Systems and methods for controlling a heat engine system are provided. One method includes initiating flow of a working fluid through a working fluid circuit having a high pressure side and a low pressure side by controlling a pump to pressurize and circulate the working fluid through the working fluid circuit and determining a configuration of the working fluid circuit by determining which of a plurality of waste heat exchangers and which of a plurality of recuperators to position in the high pressure side of the working fluid circuit. The method also includes determining, based on the determined configuration of the working fluid circuit, for each of a plurality of valves, whether to position each respective valve in an opened position, a closed position, or a partially opened position and actuating each of the plurality of valves to the determined opened position, closed position, or partially opened position.

A system (100) comprises a cryogenic engine (16) and a power generation apparatus, wherein the cryogenic engine and the power generation apparatus are coupled with each other to permit the cryogenic engine (16) and the power generation apparatus to work co-operatively with each other in a synergistic manner. The cryogenic engine (16) and the power generation apparatus are mechanically and optionally thermally coupled with each other so that the output means is shared between the cryogenic engine (16) and the power generation apparatus and that the two systems can be operated in the most power efficient manner and may also thermally interact to the potential advantage of both performance and economy.

A system (100) comprises a cryogenic engine (16) and a power generation apparatus, wherein the cryogenic engine and the power generation apparatus are coupled with each other to permit the cryogenic engine (16) and the power generation apparatus to work co-operatively with each other in a synergistic manner. The cryogenic engine (16) and the power generation apparatus are mechanically and optionally thermally coupled with each other so that the output means is shared between the cryogenic engine (16) and the power generation apparatus and that the two systems can be operated in the most power efficient manner and may also thermally interact to the potential advantage of both performance and economy.

Heat engine systems having selectively configurable working fluid circuits are provided. One heat engine system includes a pump that circulates a working fluid through a working fluid circuit and an expander that receives the working fluid from a high pressure side of the working fluid circuit and converts a pressure drop in the working fluid to mechanical energy. A plurality of waste heat exchangers are each selectively positioned in or isolated from the high pressure side. A plurality of recuperators are each selectively positioned in or isolated from the high pressure side and the low pressure side. A plurality of valves are actuated to enable selective control over which of the plurality of waste heat exchangers is positioned in the high pressure side, which of the plurality of recuperators is positioned in the high pressure side, and which of the plurality of recuperators is positioned in the low pressure side.

Heat engine systems having selectively configurable working fluid circuits are provided. One heat engine system includes a pump that circulates a working fluid through a working fluid circuit and an expander that receives the working fluid from a high pressure side of the working fluid circuit and converts a pressure drop in the working fluid to mechanical energy. A plurality of waste heat exchangers are each selectively positioned in or isolated from the high pressure side. A plurality of recuperators are each selectively positioned in or isolated from the high pressure side and the low pressure side. A plurality of valves are actuated to enable selective control over which of the plurality of waste heat exchangers is positioned in the high pressure side, which of the plurality of recuperators is positioned in the high pressure side, and which of the plurality of recuperators is positioned in the low pressure side.

A fluid expander is disclosed as used in conjunction with an air compressor that is driven by a prime mover. The fluid expander is structured to extract useful work from a fluid stream and add that work to the work provided by the prime mover to the compressor. In some embodiments a clutch can be used to decouple the expander from the compressor if insufficient work is developed by the expander. A gear train can also be used to change the rotational speed prior to work being delivered to the compressor.