Abstract: Methods and systems for recuperated superheat return are provided. A coolant is supplied in a vapor state to a compressor. The coolant compressed by the compressor is cooled with a gas cooler. The coolant cooled by the gas cooler is supplied to an inlet of a high pressure side of a recuperator. The coolant from an outlet of the high pressure side of the recuperator is supplied to a portion of a coolant circuit. The coolant is supplied back from the portion of the coolant circuit to an inlet of a low pressure side of the recuperator. The coolant in the low pressure side of the recuperator is heated with thermal energy transferred by the recuperator from the coolant in the high pressure side of the recuperator. The coolant in the vapor state from an outlet of the low pressure side of the recuperator is supplied to the compressor.

Abstract: A continuous reinforced cold water pipe (CWP) for an Ocean Thermal Energy Conversion (OTEC) system is formed from a sequential series of molded pipe sections, which are formed from a series of rigid frame sections and a curable material to form the continuous reinforced CWP. Each molded pipe section is formed by moving a rigid frame section into a mold, enclosing at least a portion of the rigid frame section in the curable material, and curing the curable material. As each molded pipe section is moved out of the mold, the next sequential rigid frame section, which is connected to the previous rigid frame section, is moved into the mold. The cycle is repeated as many times as required to form the continuous reinforced CWP having a desired length.

Abstract: A continuous reinforced cold water pipe (CWP) for an Ocean Thermal Energy Conversion (OTEC) system is formed from a sequential series of molded pipe sections, which are formed from a series of rigid frame sections and a curable material to form the continuous reinforced CWP. Each molded pipe section is formed by moving a rigid frame section into a mold, enclosing at least a portion of the rigid frame section in the curable material, and curing the curable material. As each molded pipe section is moved out of the mold, the next sequential rigid frame section, which is connected to the previous rigid frame section, is moved into the mold. The cycle is repeated as many times as required to form the continuous reinforced CWP having a desired length.

Abstract: Methods and systems for recuperated superheat return are provided. A coolant is supplied in a vapor state to a compressor. The coolant compressed by the compressor is cooled with a gas cooler. The coolant cooled by the gas cooler is supplied to an inlet of a high pressure side of a recuperator. The coolant from an outlet of the high pressure side of the recuperator is supplied to a portion of a coolant circuit. The coolant is supplied back from the portion of the coolant circuit to an inlet of a low pressure side of the recuperator. The coolant in the low pressure side of the recuperator is heated with thermal energy transferred by the recuperator from the coolant in the high pressure side of the recuperator. The coolant in the vapor state from an outlet of the low pressure side of the recuperator is supplied to the compressor.

Abstract: Enclosures are described that encapsulate or surround a joint between two or more elements, for example two pipes or a pipe and a valve. The enclosures prevent direct contact between the joint and the surrounding water, for example fresh or salt water, and prevent biofouling and corrosion of the joint. An enclosure encapsulates the joint and forms an enclosed space around the joint. Some or all of the enclosure includes a flexible material. The enclosed space is filled with a protective liquid that is retained in the enclosed space and that will be in direct contact with the joint. Due to the flexible nature of the flexible material, the pressure inside the enclosed space is maintained substantially equal to the exterior pressure outside the membrane.

Abstract: A continuous reinforced cold water pipe (CWP) for an Ocean Thermal Energy Conversion (OTEC) system is formed from a sequential series of molded pipe sections, which are formed from a series of rigid frame sections and a curable material to form the continuous reinforced CWP. Each molded pipe section is formed by moving a rigid frame section into a mold, enclosing at least a portion of the rigid frame section in the curable material, and curing the curable material. As each molded pipe section is moved out of the mold, the next sequential rigid frame section, which is connected to the previous rigid frame section, is moved into the mold. The cycle is repeated as many times as required to form the continuous reinforced CWP having a desired length.

Abstract: A heat-exchanger module that conveys a fluid through one or more heat exchangers with little or no pressure drop is presented. The heat-exchanger module comprises a first manifold that smoothly channels the fluid from a fluid source to each of the heat exchangers. The heat-exchanger module further comprises a second manifold that smoothly channels the fluid from the heat exchangers to a fluid sink. The manifolds are dimensioned and arranged to mitigate development of pressure drops in the fluid flow.

Abstract: A heat exchanger module for thermally coupling a first fluid and second fluid is disclosed. The heat exchanger module comprises a plurality of heat exchangers, each of which is fluidically coupled to a common seawater inlet and a common seawater outlet. The heat exchanger module is dimensioned and arranged for integrating with an OTEC system located on an offshore platform that is deployed in a body of water. The heat exchanger module physically and fluidically couples with ports included in pontoons attached to the offshore platform. The ports are individually controllable so that the module can be added or removed from the OTEC system without interrupting operation of other heat exchanger modules integrated with the OTEC system.

Abstract: A cooling system and process in an OTEC system are described where the sub-cooled working liquid from the working fluid pump outlet is used to cool the working fluid pump motor, either directly or indirectly via heat exchange with a secondary fluid. The heat from the motor that is being rejected into the working fluid just prior to the working fluid flowing to the evaporator helps to alleviate heat duty in the evaporator meaning more potential for the evaporator to create energy. Also, because two-phase evaporators, such as those in an OTEC system, are less efficient than single-phase heat exchangers at single-phase heating, this pre-heating of the working fluid will help the evaporator performance substantially.

Abstract: Fluid conveying pipes and processes of forming such pipes using friction stir welding. The fluid conveying pipes are formed from a pipe section that includes a first barrel coaxially and concentrically disposed within a second barrel. The first barrel and the second barrel are each formed from one or more sections or plates where longitudinal extending facing edges of the plates are friction stir welded (FSW) together along a seam(s) that extends longitudinally from the first end to the second end thereof. A plurality of the pipe sections can be connected together end to end using circumferential FSW seams to form a pipe.

Abstract: Fluid conveying pipes and processes of forming such pipes using friction stir welding. The fluid conveying pipes are formed from a pipe section that includes a first barrel coaxially and concentrically disposed within a second barrel. The first barrel and the second barrel are each formed from one or more sections or plates where longitudinal extending facing edges of the plates are friction stir welded (FSW) together along a seam(s) that extends longitudinally from the first end to the second end thereof. A plurality of the pipe sections can be connected together end to end using circumferential FSW seams to form a pipe.

Abstract: Enclosures are described that encapsulate or surround a joint between two or more elements, for example two pipes or a pipe and a valve. The enclosures prevent direct contact between the joint and the surrounding water, for example fresh or salt water, and prevent biofouling and corrosion of the joint. An enclosure encapsulates the joint and forms an enclosed space around the joint. Some or all of the enclosure includes a flexible material. The enclosed space is filled with a protective liquid that is retained in the enclosed space and that will be in direct contact with the joint. Due to the flexible nature of the flexible material, the pressure inside the enclosed space is maintained substantially equal to the exterior pressure outside the membrane.

Abstract: A cooling system and process in an OTEC system are described where the sub-cooled working liquid from the working fluid pump outlet is used to cool the working fluid pump motor, either directly or indirectly via heat exchange with a secondary fluid. The heat from the motor that is being rejected into the working fluid just prior to the working fluid flowing to the evaporator helps to alleviate heat duty in the evaporator meaning more potential for the evaporator to create energy. Also, because two-phase evaporators, such as those in an OTEC system, are less efficient than single-phase heat exchangers at single-phase heating, this pre-heating of the working fluid will help the evaporator performance substantially.

Abstract: A pontoon that includes infrastructure for fluidically coupling a heat exchanger or heat exchanger module into each of the seawater and working-fluid distribution systems of an OTEC power generation system is provided. In some embodiments, a pontoon comprises: (1) a first passage for conveying seawater between a first port and a second port at which a heat exchanger module can be connected; and (2) a conduit and connectors for connecting the heat exchanger module and the working fluid circulation system—even while the heat exchanger module is submerged. In some embodiments, pontoons in accordance with the present invention enable heat exchangers or heat exchanger modules to be added or removed to an OTEC system without disrupting the operation of other heat exchangers or heat exchanger modules in use in the OTEC system.

Abstract: A power system based on a binary power cycle and utilizing a multi-component working fluid is disclosed. The working fluid is partially vaporized and a split recirculation approach is used to control the enthalpy-temperature profiles to match the heat source. A portion of the unvaporized working fluid is sprayed into the condenser.

Abstract: A heat exchanger module for thermally coupling a first fluid and second fluid is disclosed. The heat exchanger module comprises a plurality of heat exchangers, each of which is fluidically coupled to a common seawater inlet and a common seawater outlet. The heat exchanger module is dimensioned and arranged for integrating with an OTEC system located on an offshore platform that is deployed in a body of water. The heat exchanger module physically and fluidically couples with ports included in pontoons attached to the offshore platform. The ports are individually controllable so that the module can be added or removed from the OTEC system without interrupting operation of other heat exchanger modules integrated with the OTEC system.

Abstract: A pontoon that includes infrastructure for fluidically coupling a heat exchanger or heat exchanger module into each of the seawater and working-fluid distribution systems of an OTEC power generation system is provided. In some embodiments, a pontoon comprises: (1) a first passage for conveying seawater between a first port and a second port at which a heat exchanger module can be connected; and (2) a conduit and connectors for connecting the heat exchanger module and the working fluid circulation system—even while the heat exchanger module is submerged. In some embodiments, pontoons in accordance with the present invention enable heat exchangers or heat exchanger modules to be added or removed to an OTEC system without disrupting the operation of other heat exchangers or heat exchanger modules in use in the OTEC system.

Abstract: A heat-exchanger module that conveys a fluid through one or more heat exchangers with little or no pressure drop is presented. The heat-exchanger module comprises a first manifold that smoothly channels the fluid from a fluid source to each of the heat exchangers. The heat-exchanger module further comprises a second manifold that smoothly channels the fluid from the heat exchangers to a fluid sink. The manifolds are dimensioned and arranged to mitigate development of pressure drops in the fluid flow.

Abstract: A power system based on a binary power cycle and utilizing a multi-component working fluid is disclosed. The working fluid is partially vaporized and a split recirculation approach is used to control the enthalpy-temperature profiles to match the heat source. A portion of the unvaporized working fluid is sprayed into the condenser.