Power cycle and system for utilizing moderate and low temperature heat sources

• US 6,769,256 B1
• Filed: 02/03/2003
• Issued: 08/03/2004
• Est. Priority Date: 02/03/2003
• Status: Expired due to Fees

• Current Assignee: Kalina Power Limited
• Original Assignee: Kalex Systems LLC
• Inventors: Kalina, Alexander I.
• Primary Examiner(s): Nguyen, Hoang
• Application Number:
  US10/357,328
• Time in Patent Office: 547 Days
• Field of Search: 606/49, 606/51, 606/71, 606/73, 606/412, 606/53, 606/76
• US Class Current: 60/653
• CPC Class Codes: F01K 25/065 with an absorption fluid remaining at least partly in the liquid state, e.g. water for ammonia F01K5/00 takes precedence

Abstract

A new thermodynamic cycle is disclosed for converting energy from a low temperature stream, external source into useable energy using a working fluid comprising of a mixture of a low boiling component and a higher boiling component and including a higher pressure circuit and a lower pressure circuit. The cycle is designed to improve the efficiency of the energy extraction process by recirculating a portion of a liquid stream prior to further cooling. The new thermodynamic processes and systems for accomplishing these improved efficiencies are especially well-suited for streams from low-temperature geothermal sources.

Claims

1. A method for implementing a thermodynamic cycle comprising the steps of:

transforming thermal energy from a fully vaporized boiling stream into a usable energy form to produce a lower pressure, spent stream;

transferring thermal energy from an external heat source stream to a boiling stream to form the fully vaporized boiling stream and a cooled external heat source stream;

transferring thermal energy from the spent stream to a first portion of a heated higher pressure, basic working fluid stream to form a partially condensed spent stream and a first pre-heated, higher pressure, basic working fluid stream;

transferring thermal energy from the cooled external heat source stream to a second portion of the heated higher pressure, basic working fluid stream to form a second pre-heated, higher pressure, basic working fluid stream and a spent external heat source stream;

combining the first and second pre-heated, higher pressure basic working fluid streams to form a combined pre-heated, higher pressure basic working fluid stream;

separating the partially condensed spent stream into a separated vapor stream and a separated liquid stream;

pressurizing a first portion of the separated liquid stream to a pressure equal to a pressure of the combined pre-heated, higher pressure basic working fluid stream to form a pressurized liquid stream;

combining the pressurized liquid stream with the combined pre-heated, higher pressure basic working fluid stream to form the boiling stream;

combining a second portion of the separated liquid stream with the separated vapor stream to from a lower pressure, basic working fluid stream;

transferring thermal energy from the lower pressure, basic working fluid stream to a higher pressure, basic working fluid stream to form the heated, higher pressure, basic working fluid stream and a cooled, lower pressure, basic working fluid stream;

transferring thermal energy cooled, lower pressure, basic working fluid stream to an external coolant stream to from a spent coolant stream and a fully condensed, lower pressure, basic working fluid stream; and

pressurizing the fully condensed, lower pressure, basic working fluid stream to the higher pressure, basic working fluid stream.

2. The method of claim 1, wherein the external heat source stream is a geothermal stream.