System and Method for Generating Steam Using a Solar Power Source in Conjunction with a Geothermal Power Source

Abstract

System and method for generating electrical power using a solar power system comprising pressurized pipes for transporting liquid water in conjunction with a geothermal power source. The pressurized pipes flow through solar collectors which concentrate light on the water flowing through the pipes. The pressurization in the pipes allows for the water to absorb large quantities of energy. The pressurized and heated water is then pumped to a heat exchanger where the thermal energy is released to produce steam for powering a steam turbine electrical generator. Thereafter, the water is returned to the solar collectors in a closed loop to repeat the process. In conjunction with the solar power system, heated water from the geothermal power source is directed through a second pipe that also traverses the heat exchanger to assist in the production of steam for powering the turbine electrical generator.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is a divisional application of U.S. patent application Ser. No. 12 / 870,202, filed on Aug. 27, 2009 and currently pending, which claims priority to U.S. provisional application No. 61 / 237,769, filed Aug. 28, 2009, each application being incorporated herein by reference.BACKGROUND OF THE INVENTION[0002]Large scale solar power plants utilizing concentrating solar power (“CSP”) technology have been in production for over twenty years. The Solar Electric Generating Systems (“SEGS”) facilities in the Mojave Desert of California are a well-known example of solar power plants using such CSP technology. Concentrating solar power utilizes solar collectors comprising large mirrors or lenses which concentrate solar energy upon an unpressurized pipe or tube that contains a heat transfer fluid. Typically, a synthetic oil having a high boiling point is used as the heat transfer fluid. For example, the SEGS facilities utilize Therminol® ...

AI Technical Summary

Benefits of technology

[0008]Disclosed herein are systems and methods for generating electrical power using a solar power system comprising pressurized pipes for transporting liquid water. The pressurized pipes flow through solar collectors which concentrate sunlight on the water flowing through said pipes. Because the pipes inside the solar collectors are pressurized, the water flowing therethrough can be heated well above the ordinary boiling point of water (100° C.). Advantageously, the systems and methods described herein rely upon the superior heat transfer capabilities of water in comparison to synthetic heat transfer fluids. Furthermore, the lack of synthetic heat transfer fluid minimizes the added costs and safety concerns associated with the use of such fluids.

[0009]Finally, the pressurized pipes described herein prevent the water flowing therethrough from flashing over to steam when heated to a high temperature. Accordingly, the instabilities and unwanted pressure drops associated with two-phase (water / steam) flow are eliminated. Furthermore, the use of water rather than steam for transporting thermal energy takes advantage of water's superior energy carrying capacity in comparison to steam.

Problems solved by technology

One disadvantage of the use of a synthetic heat transfer fluid is that the fluid has a relatively low energy density.

Another disadvantage of synthetic heat transfer fluids is that they are often flammable.

Such DSG systems have their own drawbacks, however.

First, the presence of steam in the pipes of the solar collectors reduces the efficiency of the collectors because steam has a significantly lower heat capacity than water.

Finally, DSG systems are more sensitive to variations in solar flux density and changes in atmospheric conditions because the systems will not function properly unless the water in the solar collectors is sufficiently heated to flash over to steam.

Taken together, these drawbacks necessitate the use of larger, more expensive solar collectors to produce a given amount of electricity.

Therefore, such DSG systems may have little or no cost savings in comparison to traditional CSP systems containing synthetic heat transfer fluid.

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