Combined geothermal and solar thermal organic rankine cycle system
AssigneeUnited Technologies Corporation
InventorsSitaram Ramaswamy, Guangyan Zhu
Life of this patent
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Abstract
In a system where the thermal energy of a geothermal fluid is applied to an ORC system, the energy is enhanced by the use of solar energy to thereby increase the temperature of the fluid being applied by the ORC system. A single heat exchanger version provides for direct heat exchange relationship with the geothermal and solar fluids, whereas a two heat exchanger version provides for each of the geothermal and solar fluids to be in heat exchange relationship with the working medium of the ORC system. Control features are provided to selectively balance the various fluid flows in the system.
Claims20
An energy recovery system for use with a geothermal source containing a fluid which can be removed at a higher temperature and returned at a lower temperature, comprising:
- an organic rankine cycle system having a closed loop circuit with a working fluid being circulated therethrough;
- at least one heat exchanger fluidly connected to said organic rankine cycle system and to be connected to a geothermal fluid for selectively transferring heat from the geothermal fluid to said organic rankine cycle system;
- a solar collector thermally coupled to said at least one heat exchanger for selectively transferring heat from said solar collector to said organic rankine cycle system;
- and
- a control for controlling the energy recovery system, said control determining whether solar heat is available from said solar collector, and if heat is available from said solar collector, determining whether sufficient solar heat is available to provide energy recovery without heat from the geothermal fluid, and operating in a solar mode alone if there is sufficient solar heat available, operating in a geothermal mode only if there is no solar heat available, and operating in combination of the solar and geothermal modes if there is solar heat available, but it is not sufficient.
A method of operating an energy recovery system comprising the steps of:
- circulating a working fluid through an organic rankine cycle system having a closed loop circuit, and at least one heat exchanger, said at least one heat exchanger receiving the working fluid, and said at least one heat exchanger being selectively heated by a geothermal fluid obtained from a geothermal source, and also being heated by a solar fluid which is heated by a solar collector also thermally coupled to said at least one heat exchanger for selectively transferring heat from said solar collector to said working fluid;
- and
- determining whether solar heat is available from said solar collector, and if heat is available from said solar collector, determining whether sufficient solar heat is available to provide energy recovery without the geothermal fluid, and operating in a solar mode alone if there is sufficient solar heat available, operating in a geothermal mode only if there is no solar heat available, and operating in combination of the solar and geothermal modes if there is solar heat available, but it is not sufficient.
Dependencies are inferred from the claim text.