US20130139807A1

US20130139807A1 - Thermal energy generation system

Info

Publication number: US20130139807A1
Application number: US13/701,516
Authority: US
Inventors: Eli Mandelberg; Ariel Rotstein
Original assignee: Heliofocus Ltd
Current assignee: Heliofocus Ltd
Priority date: 2010-06-07
Filing date: 2011-06-06
Publication date: 2013-06-06
Also published as: CN103403468A; WO2011154945A2; WO2011154945A3

Abstract

A thermal energy generation system having a working fluid and a system fluid, including an energy system for heating the working fluid by applying heat thereto, a main heat exchanger assembly for transferring heat from the working fluid to the system fluid, a thermal energy consumption system for receiving the heated system fluid from the main heat exchanger assembly when the temperature of the system fluid is at or above a predetermined temperature, and a thermal energy conservation assembly for receiving the heated system fluid from the main heat exchanger assembly and for reintroducing the system fluid thereto when the temperature of the system fluid is less than the predetermined temperature.

Description

FIELD OF THE INVENTION

The present invention relates generally to thermal energy generation systems.

BACKGROUND OF THE INVENTION

Thermal energy generation systems that generate thermal energy by combustion of fossil fuels are well known.
Thermal energy generation systems that generate thermal energy by use of renewable energy, such as solar energy, are gaining recognition. These thermal energy systems exploit solar energy to provide heat to thermal energy consumption systems typically in the form of a fluid heated to a predetermined temperature.

SUMMARY OF THE INVENTION

There is thus provided in accordance with an embodiment of the invention a thermal energy generation system having a working fluid and a system fluid, including an energy system for heating the working fluid by applying heat thereto, a main heat exchanger assembly for transferring heat from the working fluid to the system fluid, a thermal energy consumption system for receiving the heated system fluid from the main heat exchanger assembly when the temperature of the system fluid is at or above a predetermined temperature, and a thermal energy conservation assembly for receiving the heated system fluid from the main heat exchanger assembly and for reintroducing the system fluid thereto when the temperature of the system fluid is less than the predetermined temperature.
In accordance with an embodiment of the invention the thermal energy conservation assembly is provided for conserving the thermal energy provided by the system fluid within the thermal energy generation system. Additionally, the energy system is selected from the group consisting of a fossil-fuel based energy system, an electrical power energy system, a renewable energy system, a geothermal energy system, a wind energy system, a wave energy system, a solar energy system, a solar concentrating system, a solar tower energy system, a Fresnel lens solar energy system, a trough-Fresnel mirror solar energy system, a linear Fresnel solar energy system, a solar heliostat concentrating energy system and a parabolic trough solar concentrating energy system.
In accordance with another embodiment of the invention the working fluid is heated by solar radiation applied thereto following concentration of the solar radiation by a dish. Additionally, the working fluid is heated within a solar receiver by solar radiation impinging thereupon. Moreover, the thermal energy conservation assembly includes an auxiliary heat exchanger assembly including at least one auxiliary heat exchanger in fluid communication with the main heat exchanger assembly, at least one auxiliary heat exchanger includes a heat providing fluid volume for providing the system fluid to the auxiliary heat exchanger assembly when the temperature of the system fluid is less than the predetermined temperature, and a heat receiving fluid volume, wherein the system fluid flowing therein is heated by the system fluid flowing within the heat providing fluid volume, and for reintroducing the heated system fluid to the main heat exchanger assembly.
In accordance with yet another embodiment of the invention the system fluid flows into the main heat exchanger assembly from a system fluid reservoir. Additionally, the system fluid is reintroduced into the main heat exchanger assembly via the system fluid reservoir, wherein the temperature of the system fluid is less than the predetermined temperature. Alternatively, the system fluid is reintroduced into the main heat exchanger assembly via conduits, wherein the temperature of the system fluid is less than the predetermined temperature.
In accordance with a further embodiment of the invention the main heat exchanger assembly includes any one of a preheater provided to heat the system fluid flowing therein by the heat transferred by the working fluid, a vapor generator provided to vaporize the system fluid flowing therein from the preheater by the heat transferred by the working fluid, and a superheater provided to heat the system fluid flowing therein from the vapor generator by the heat transferred by the working fluid. Additionally, a vapor drum is in fluid communication with the vapor generator. Furthermore, the thermal energy generation system includes a vapor storage device for storing the vaporized system fluid.
There is thus provided in accordance with another embodiment of the invention a thermal energy generation system having a working fluid and a system fluid, including a solar energy system for heating the working fluid by applying solar radiation thereto, a main heat exchanger assembly for transferring heat from the working fluid to the system fluid, a thermal energy consumption system for receiving the heated system fluid from the main heat exchanger assembly when the temperature of the system fluid is at or above a predetermined temperature, and an auxiliary heat exchanger assembly including at least one auxiliary heat exchanger in fluid communication with the main heat exchanger assembly, the at least one auxiliary heat exchanger including a heat providing fluid volume for providing the system fluid to the auxiliary heat exchanger assembly when the temperature of the system fluid is less than the predetermined temperature, and a heat receiving fluid volume, wherein the system fluid flowing therein is heated by the system fluid flowing within the heat providing fluid volume, and for reintroducing the heated system fluid to the main heat exchanger assembly.
In accordance with an embodiment of the invention the solar energy system includes a solar concentrating system operative to heat the working fluid by concentrated solar radiation. Additionally, the solar radiation is concentrated by a dish. Furthermore, the working fluid is heated within a solar receiver by solar radiation impinging thereupon.
In accordance with another embodiment of the invention the system fluid flows into the main heat exchanger assembly from a system fluid reservoir. Additionally, the system fluid is reintroduced into the auxiliary heat exchanger assembly via the system fluid reservoir. Moreover, the main heat exchanger assembly includes any one of a preheater provided to heat the system fluid flowing therein by the heat transferred by the working fluid, a vapor generator provided to vaporize the system fluid flowing therein from the preheater by the heat transferred by the working fluid, and a superheater provided to heat the system fluid flowing therein from the vapor generator by the heat transferred by the working fluid.
In accordance with yet another embodiment of the invention the thermal energy generation system includes a vapor storage device for storing the vaporized system fluid. Additionally, the vapor storage device includes a vapor drum designed to store the vaporized system fluid. Moreover, the vapor drum is heated by the vapor generator.
There is thus provided in accordance with yet another embodiment of the invention a thermal energy generation system having a working fluid and a system fluid, including a system fluid reservoir for storing the system fluid, a solar energy system for heating the working fluid by applying solar radiation thereto, a main heat exchanger assembly for receiving the system fluid from the reservoir, for receiving the working fluid from the solar energy system, and for transferring heat therebetween, wherein the main heat exchanger assembly includes any one of a preheater for heating the system fluid, by the heat transferred thereto by the working fluid, a vapor generator for receiving the system fluid from the preheater and for vaporizing the system fluid by the heat transferred thereto by the working fluid therein, and a superheater for receiving the system fluid from the vapor generator and for transferring heat to the system fluid from the working fluid, a thermal energy consumption system for receiving the heated system fluid from the superheater when the temperature of the system fluid is at or above a predetermined temperature, and an auxiliary heat exchanger assembly including at least one auxiliary heat exchanger in fluid communication with any one of the preheater, the vapor generator, the superheater and the system fluid reservoir, the at least one auxiliary heat exchanger including a heat providing fluid volume for providing the system fluid to the auxiliary heat exchanger assembly when the temperature of the system fluid is less than the predetermined temperature and providing the system fluid to the system fluid reservoir, and a heat receiving fluid volume, wherein the system fluid flowing therein from the system fluid reservoir is heated by the system fluid flowing within the heat providing fluid volume, and for reintroducing the heated system fluid to any one of the preheater, the vapor generator, the superheater and the system fluid reservoir.
In accordance with an embodiment of the invention the solar energy system includes a solar concentrating system operative to heat the working fluid by concentrated solar radiation. Additionally, the solar radiation is concentrated by a dish. Moreover, the working fluid is heated within a solar receiver by solar radiation impinging thereupon.
In accordance with another embodiment of the invention the thermal energy generation system includes a vapor storage device for storing the vaporized system fluid. Additionally, the vapor storage device includes a vapor drum designed to store the vaporized system fluid. Moreover, the vapor drum is heated by the vapor generator.
There is thus provided in accordance with still another embodiment of the invention a method for generating thermal energy including heating a working fluid by impingement of solar radiation thereon, transferring heat from the working fluid to a system fluid flowing within a main heat exchanger assembly, utilizing thermal energy provided by heat within the system fluid to operate a thermal energy consumption system, wherein the system fluid enters therein from the main heat exchanger assembly at or above a predetermined temperature, and reintroducing the system fluid into the main heat exchanger assembly, wherein the temperature of the system fluid is less than the predetermined temperature.
There is thus provided in accordance with a further embodiment of the invention a method for generating thermal energy including healing a working fluid by impingement of solar radiation thereon, transferring heat from the working fluid to a system fluid flowing within a main heat exchanger assembly, utilizing thermal energy provided by heat within the system fluid to operate a thermal energy consumption system, wherein the system fluid enters therein from the main heat exchanger assembly at or above a predetermined temperature, directing the system fluid to flow within a heat providing fluid volume of an auxiliary heat exchanger assembly wherein the temperature of the system fluid is less than the predetermined temperature, heating the system fluid within a heat receiving fluid volume of the auxiliary heat exchanger assembly by the system fluid flowing within the heat providing fluid volume, and reintroducing the system fluid exiting the heat receiving fluid volume into the main heat exchanger assembly so as to be heated by the working fluid.

BRIEF DESCRIPTION OF THE DRAWING

The present subject matter will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which:

FIGS. 1A-1D are a simplified schematic illustration of a thermal energy generation system, constructed and operative in accordance with an embodiment of the present invention, at a first, second, third and fourth operative mode, respectively;

FIGS. 2A and 2B are a simplified schematic illustration of a thermal energy generation system, constructed and operative in accordance with another embodiment of the present invention, at a first and second operative mode, respectively; and

FIGS. 3A and 3B are a simplified schematic illustration of a thermal energy generation system, constructed and operative in accordance with yet another embodiment of the present invention, at a first and second operative mode, respectively.

DETAILED DESCRIPTION OF EMBODIMENTS

In the following description, various aspects of the present subject matter will be described. For purposes of explanation, specific configurations and details are set forth in order to provide a thorough understanding of the present subject matter. However, it will also be apparent to one skilled in the art that the present subject matter may be practiced without specific details presented herein without departing from the scope of the present invention. Furthermore, the description omits and/or simplifies some well known features in order not to obscure the description of the subject matter.
Reference is now made to FIGS. 1A-1D, which are each a simplified schematic illustration of a thermal energy generation system, constructed and operative in accordance with an embodiment of the present invention, at a first, second, third and fourth operative mode, respectively. As seen in FIGS. 1A-1D, a thermal energy generation system 100 comprises an energy system. The energy system may be any suitable energy system operative to heat a working fluid. For example, the energy system may comprise a fossil-fuel based energy system, an electrical power energy system or a renewable energy system. Examples of renewable energy systems are solar energy systems, geothermal energy systems, wind or wave energy systems. In the embodiment shown in FIGS. 1A-1D, the thermal energy generation system 100 comprises a solar energy system, which may be any suitable solar concentrating system 110. The solar concentrating system 110 is operative to heat a working fluid 114, flowing within the solar concentrating system 110, by concentrated solar radiation impinging upon the working fluid 114.
The solar concentrating system 110 may comprise a sun-tracking concentrator or an array of sun-tracking mirrors. As seen in FIGS. 1A-1D, the solar concentrating system 110 may comprise a solar receiver 120 provided to heat the working fluid 114 by concentrated solar radiation impinging thereon. The solar radiation may be concentrated by any suitable means, such as by a dish 124. Any suitable working fluid 114 may flow within the solar concentrating system 110, such as a gas, typically air, helium or carbon dioxide, or a liquid such as oil, water, an organic fluid or molten salt, for example. Wherein the working fluid 114 is a liquid, such as molten salt, oil, an organic fluid or water, the receiver 120 may be a tubular receiver operative to heat the liquid therein. Alternatively, the receiver 120 may be a volumetric receiver wherein the working fluid 114 is a gas, such as air, helium or carbon dioxide.
The solar concentrating system 104 may comprise a single receiver 120 and dish 124 or a plurality of receivers and dishes (not shown). The plurality of receivers and dishes may be arranged in parallel or in series. In the embodiment shown in FIGS. 1A-1D, the solar concentrating system 110 is configured as a closed loop cycle, though it is appreciated that an open loop cycle may be utilized.
It is appreciated that the solar energy system may be any suitable solar energy system, such as a solar tower energy system, a Fresnel lens solar energy system, a trough-Fresnel mirror solar energy system, a linear Fresnel solar energy system, a solar heliostat concentrating energy system and a parabolic trough solar concentrating energy system or any other suitable solar concentrating system, for example.
The working fluid 114 may flow into a main heat exchanger assembly 140 configured for transferring heat from the working fluid 114 to a system fluid 144, flowing within the main heat exchanger assembly 140. The system fluid 144 may be any suitable fluid such as a gas, typically air, helium or carbon dioxide, or a liquid such as oil, water, an organic fluid or molten salt, for example. It is noted that the working fluid 114 may be the same as the system fluid 144. Alternatively, the working fluid 114 may be different than the system fluid 144.
The system fluid 144 may flow into the main heat exchanger assembly 140 from a system fluid reservoir 150, typically in a liquid state. The system fluid 144 may be introduced into the reservoir 150 by a liquid supply line 160. Any suitable deaerator (not shown) may be provided so as to remove gases from the system fluid reservoir 150 or remove gases from any other component within the thermal energy generation system 100.
A pump 164 may be provided intermediate the reservoir 150 and the main heat exchanger assembly 140 so as to ensure the system fluid 144 continuously flows from the reservoir 150 to the main heat exchanger assembly 140.
It is noted that wherein the system fluid 144 is a gas, such as air, a blower may be provided to ensure continuous flow thereof, and wherein the system fluid 144 is a liquid, such as water, a pump, such as the pump 164, may be provided to ensure continuous flow thereof. It is further noted that additional blowers and/or pumps may be added to the thermal energy generation system 100 to ensure that the system fluid 144 and the working fluid 114 flow continuously. Additionally, some of the pumps and/or valves described herein may be obviated. The pumps and blowers may be any suitable pump and blowers known in the art.
As seen in FIG. 1A, a first operative mode is shown wherein the system fluid 144 flows along a flowpath 170. The system fluid 144 flows out of the reservoir 150 via the pump 164 and a valve 172 to the main heat exchanger assembly 140 wherein the system fluid 144 is heated by the working fluid 114.
The heated system fluid 144 flows out of the main heat exchanger assembly 140. In the first operative mode, shown in FIG. 1A, the system fluid 144 may be introduced into a thermal energy consumption system 180 via a valve 182 upon being sufficiently heated by the working fluid 114 to or above a predetermined temperature.
The thermal energy consumption system 180 is designed to utilize the thermal energy provided by the system fluid 144 wherein the system fluid 144 enters therein at or above the predetermined temperature.
The thermal energy consumption system 180 may comprise any system operative to utilize the thermal energy of the heated system fluid 144. For example, the thermal energy consumption system may comprise an industrial system. Moreover, the thermal energy provided to the thermal energy consumption system may be utilized for vaporization, pasteurization or any other thermal energy consuming process used in the chemical industry or any other industry. The thermal energy provided to the thermal energy consumption system may be used for drying, such as drying polymer containing products, for example. The thermal energy provided to the thermal energy consumption system may be used within a vapor turbine, such as a steam turbine, for generation of electricity therefrom. Additionally, the thermal energy provided to the thermal energy consumption system may be utilized to boost a vapor turbine, typically a steam turbine, such as a coal or gas fuel fired steam turbine or a steam turbine comprised in a combined cycle gas fired system. The thermal energy provided to the thermal energy consumption system may be utilized for direct heating of a solid desiccant system, such as a desiccant system comprised in an air conditioning system. Furthermore, the thermal energy provided to the thermal energy consumption system may be used for absorption cooling.
Residual thermal energy exiting the thermal energy consumption system 180, following consumption of the thermal energy within the thermal energy consumption system 180, may be further used within any other thermal energy consumption system or alternatively may be introduced back into the thermal energy generation system 100.
Turning to FIG. 1B, a second operative mode is shown wherein the temperature of the system fluid 144 flowing out of the main heat exchanger assembly 140 is less than the predetermined temperature.
The system fluid 144 may fail to reach the predetermined temperature prior to entering the thermal energy consumption system 180 at times the concentrated solar radiation may be insufficient to heat the working fluid 114 to a desired temperature capable for heating the system fluid 144 to the predetermined temperature. Insufficient concentrated solar radiation may typically occur during early morning, evening and nighttime.
The system fluid 144 may be directed to enter a thermal energy conservation assembly 188. The thermal energy conservation assembly 188 is provided for conserving the thermal energy of the system fluid 144, by reintroducing the system fluid 144 into the main heat exchanger assembly 140, whereupon the system fluid 144 is less than the predetermined temperature. As seen in FIG. 1B, the thermal energy conservation assembly 188 may comprise an auxiliary heat exchanger assembly 190 designated to reintroduce the system fluid 144 into the main heat exchanger assembly 140. The system fluid 144 may be directed to enter the auxiliary heat exchanger assembly 190 via the valves 182, 194 and 196 along a flowpath 198. The auxiliary heat exchanger assembly 190 may comprise at least one heat exchanger 201. The heat exchanger 201 may include a heat providing fluid volume 200 and a corresponding heat receiving fluid volume 202. The system fluid 144 flowing within the heat providing fluid volume 200 heats the system fluid 144 flowing within the corresponding heat receiving fluid volume 202, as will be described hereinbelow.
The system fluid 144 may enter the heat providing fluid volume 200 of the auxiliary heat exchanger assembly 190 so as to heat the system fluid 144 flowing within the corresponding heat receiving fluid volume 202. The system fluid 144 thereafter may exit the heat providing fluid volume 200 and flow to the reservoir 150. The system fluid 144 may flow to the reservoir 150 via valves 204 and 206 and a pump 210 wherein the pressure of the system fluid 144 is less than the pressure of the liquid within the reservoir 150. Alternatively, the system fluid 144 may flow to the reservoir 150 via the valves 204 and 212 and a valve 214, which valve 214 may be an expansion valve, wherein the pressure of the system fluid 144 is greater than the pressure of the liquid within the reservoir 150.
The liquid supply line 160 may be shut. Shutting the liquid supply line 160 may allow controlling the pressure degree of the liquid within the reservoir 150. Alternatively, the liquid supply line 160 may be partially open or fully open and new liquid may be introduced into the reservoir 150. Partially or fully opening the liquid supply line 160 may allow controlling the pressure degree of the liquid within the reservoir 150 and/or may allow for additional system fluid 144 to be introduced into the thermal energy generation system 100 for consumption within the thermal energy consumption system 180.
The system fluid 144 exiting the reservoir 150 may enter the heat receiving fluid volume 202 within the auxiliary heat exchanger assembly 190, via the pump 164 and the valve 172. The fluid system 144 flowing within the heat receiving fluid volume 202 may be heated by the system fluid 144 flowing within the corresponding heat providing fluid volume 200.
The system fluid 144 may thereafter exit the heat receiving fluid volume 202 and flow back to the main heat exchanger assembly 140 via a valve 234 to be heated by the working fluid 114 flowing therein.
Upon heating the system fluid 144 within the main heat exchanger assembly 140, by heat transferred from the working fluid 114, the system fluid 144 may enter the thermal energy consumption system 180 wherein the system fluid temperature is at or above the predetermined temperature, as shown in FIG. 1A. Wherein the system fluid temperature is less than the predetermined temperature, the system fluid 144 may be reintroduced into the auxiliary heat exchanger assembly 190 to follow flowpath 198, as shown in FIG. 1B. Alternatively, the system fluid 144 may be reintroduced into the reservoir 150, as shown in FIG. 1C or may be reintroduced into the main heat exchanger assembly 140, as shown in FIG. 1D.
Introducing the system fluid 144 into the auxiliary heat exchanger assembly 190, as shown in FIG. 1B, allows for minimizing a decrease in the system fluid temperature which would have occurred had the system fluid 144 been directed to flow from the reservoir 150 directly into the main heat exchanger assembly 140. This is in virtue of the transfer of heat from the system fluid 144, flowing within the heat providing fluid volume 200, to the system fluid 144 flowing within the corresponding heat receiving fluid volume 202.
The main heat exchanger assembly 140 and the auxiliary heat exchanger assembly 190 may each comprise a plurality of heat exchangers, as will be further described in reference to FIGS. 2A-3B. The main heat exchanger assembly 140 and the auxiliary heat exchanger assembly 190 may comprise any suitable configuration allowing a fluid to be heated therein. For example, the main heat exchanger assembly 140 and the auxiliary heat exchanger assembly 190 may each be configured as a shell and tube heat exchanger, a plate heat exchanger, or any other suitable configuration.
It is appreciated that the thermal energy generation system 100 may comprise any suitable heating element operative to heat a fluid flowing within the thermal energy generation system 100. Additionally, the thermal energy generation system 100 may comprise any suitable thermal energy storage device for storing thermal energy generated by the thermal energy generation system 100. Moreover, the thermal energy generation system 100 may comprise any suitable vapor storage device, such as a vapor drum described in reference to FIGS. 3A and 3B hereinbelow.
Other features and advantages of the present invention are apparent from the different examples. The provided examples illustrate different components and methodology useful in practicing the present invention. The examples do not limit the claimed invention. Based on the present disclosure the skilled artisan can identify and employ other components and methodology useful for practicing the present invention.
The following non-limiting example describes the embodiment shown in FIGS. 1A and 1B, at a discrete point in time during the operation of the thermal energy generation system 100. The working fluid 114 may be air which enters the receiver 120 at a temperature of approximately 50° C. The air is heated by concentrated solar radiation to a temperature of approximately 400° C. The heated air enters the main heat exchanger assembly 140. The system fluid 144 may be water, which flows out of the reservoir 150 at a temperature of approximately 20° C. into the main heat exchanger assembly 140, following the flowpath 170, shown in FIG. 1A. The system fluid 144 is heated within the main heat exchanger assembly 140 by the heated air and exits the main heat exchanger assembly 140 at an elevated temperature of approximately 300° C. The predetermined temperature is 450° C. Therefore the system fluid 144 is not introduced into the thermal energy consumption system 180 and is rather directed to flow into the heat providing fluid volume 200 of the auxiliary heat exchanger assembly 190, as illustrated by the flowpath 198 in FIG. 1B. The system fluid 144 exits the heat providing fluid volume 200 at a reduced temperature of approximately 50° C., following heating for the transfer of thermal energy therefrom to a corresponding system fluid 144 flowing within the heat receiving fluid volume 202. The system fluid 144 flows from the heat providing fluid volume 200 to the reservoir 150, wherein the reservoir water is at a temperature of approximately 20° C. The system fluid 144 flows from the reservoir 150 to the heat receiving fluid volume 202 at a temperature of approximately 40° C. The system fluid 144 flows out of the heat. receiving fluid volume 202 at an elevated temperature of approximately 250° C. and enters the main heat exchanger assembly 140. The system fluid 144 is heated within the main heat exchanger assembly 140 by the air to an elevated temperature of approximately 380° C. The system fluid 144, which has yet to reach the predetermined temperature, may be reintroduced into the auxiliary heat exchanger assembly 190 to flow according to the flowpath 198 shown in FIG. 1B or may be reintroduced into the reservoir 150, as shown in FIG. 1C or may be reintroduced into the main heat exchanger assembly 140, as shown in FIG. 1D. The system fluid 144 may thus circulate until the temperature of the air is heated by the concentrated solar radiation to a degree sufficient to heat the system fluid 144 to a temperature above or at the predetermined temperature. Whereupon the system fluid 144 is at or above the predetermined temperature the system fluid may be introduced into the thermal energy consumption system 180.
Turning to FIG. 1C, a third operative mode is shown wherein the temperature of the system fluid 144 flowing out of main heat exchanger assembly 140 is less than the predetermined temperature. FIG. 1C illustrates an alternative flowpath 240 to the flowpath 198 of FIG. 1B.
The system fluid 144 may be directed to enter the thermal energy conservation assembly 188 so as to reintroduce the system fluid 144 into the main heat exchanger assembly 140. As seen in FIG. 1C, the thermal energy conservation assembly 188 includes the reservoir 150 allowing the system fluid 144 to flow therethrough so as to be reintroduced into the main heat exchanger assembly 140.
The system fluid 144 may be directed to flow to the reservoir 150, via the valves 182, 194 and 212. The system fluid 144 may enter the reservoir 150 via the valve 204 and the pump 210 wherein the pressure of the system fluid 144 is less than the pressure of the liquid within the reservoir 150. Alternatively, the system fluid 144 may flow to the reservoir 150 via the valve 214 wherein the pressure of the system fluid 144 is greater than the pressure of the liquid within the reservoir 150.
The liquid supply line 160 may be shut or alternatively, the liquid supply line 160 may be partially open and new liquid may be introduced into the reservoir 150.
The system fluid 144 may thereafter exit the reservoir 150 and flow back to the main heat exchanger assembly 140 via the pump 164 and the valve 172 to be heated by the working fluid 114 flowing therein.
Upon heating the system fluid 144 within the main heat exchanger assembly 140 the system fluid 144 may enter the thermal energy consumption system 180 wherein the system fluid 144 temperature is at or above the predetermined temperature, as shown in FIG. 1A. Wherein the system fluid 144 temperature is less than the predetermined temperature the system fluid 144 may be reintroduced into the auxiliary heat exchanger assembly 190 to follow flowpath 198, as shown in FIG. 1B. Alternatively, the system fluid 144 may be reintroduced into the reservoir 150, as shown in FIG. 1C or may be reintroduced into the main heat exchanger assembly 140, as shown in FIG. 1D.
The following non-limiting example describes the embodiment shown in FIGS. 1A and 1C, at a discrete point in time during the operation of the thermal energy generation system 100. The working fluid 114 may be air which enters the receiver 120 at a temperature of approximately 50° C. The air is heated by concentrated solar radiation to a temperature of approximately 400° C. The heated air enters the main heat exchanger assembly 140. The system fluid 144 may be water, which flows out of the reservoir 150 at a temperature of approximately 20° C. into the main heat exchanger assembly 140, following flowpath 170, shown in FIG. 1A. The system fluid 144 is heated within the main heat exchanger assembly 140 by the heated air and exits the main heat exchanger assembly 140 at an elevated temperature of approximately 300° C. The predetermined temperature is 500° C. and therefore the system fluid 144 is not introduced into the thermal energy consumption system 180 and is rather directed to flow into the reservoir 150, as illustrated by the flowpath 240 in FIG. 1C. The reservoir water is at a temperature of approximately 20° C. The system fluid 144 flows from the reservoir 150 to the main heat exchanger assembly 140 at a temperature of approximately 40° C. The system fluid 144 is heated within the main heat exchanger assembly 140 by the air to an elevated temperature of approximately 350° C. The system fluid 144, which has yet to reach the predetermined temperature, may be reintroduced into the auxiliary heat exchanger assembly 190 to flow according to the flowpath 198 shown in FIG. 1B or may be reintroduced into the reservoir 150, as shown in FIG. 1C or may be reintroduced into the main heat exchanger assembly 140, as shown in FIG. 1D. The system fluid 144 may thus circulate until the temperature of the air is heated by the concentrated solar radiation to a degree sufficient to heat the system fluid 144 to a temperature above or at the predetermined temperature. Whereupon the system fluid 144 is at or above the predetermined temperature the system fluid may be introduced into the thermal energy consumption system 180.
Turning to FIG. 1D, a fourth operative mode is shown wherein the temperature of the system fluid 144 flowing out of the main heat exchanger assembly 140 is less than the predetermined temperature. FIG. 1D illustrates an alternative flowpath 250 to the flowpath 198 of FIG. 1B or the flowpath 240 of FIG. 1C.
The system fluid 144 may be directed to enter the thermal energy conservation assembly 188 so as to reintroduce the system fluid 144 into the main heat exchanger assembly 140. As seen in FIG. 1D, the thermal energy conservation assembly 188 includes conduits 252 allowing the system fluid 144 to flow therethrough so as to be reintroduced into the main heat exchanger assembly 140.
The system fluid 144 may be directed to flow back to the main heat exchanger assembly 140, via the conduits 252 and the valves 182, 194, 196 and 234.
Upon heating the system fluid 144 within the main heat exchanger assembly 140 the system fluid 144 may enter the thermal energy consumption system 180 wherein the system fluid 144 temperature is at or above the predetermined temperature, as shown in FIG. 1A. Wherein the system fluid 144 temperature is less than the predetermined temperature the system fluid 144 may be reintroduced into the auxiliary heat exchanger assembly 190 to follow the flowpath 198, as shown in FIG. 1B. Alternatively, the system fluid 144 may be reintroduced into the reservoir 150, as shown in FIG. 1C or may be reintroduced into the main heat exchanger assembly 140, as shown in FIG. 1D.
The following non-limiting example describes the embodiment shown in FIGS. 1A and 1D, at a discrete point in time during the operation of the thermal energy generation system 100. The working fluid 114 may be air which enters the receiver 120 at a temperature of approximately 50° C. The air is heated by concentrated solar radiation to a temperature of approximately 400° C. The heated air enters the main heat exchanger assembly 140. The system fluid 144 may be water which flows out of the reservoir 150 at a temperature of approximately 20° C. into the main heat exchanger assembly 140, following flowpath 170, shown in FIG. 1A. The system fluid 144 is heated within the main heat exchanger assembly 140 by the heated air and exits the main heat exchanger assembly 140 at an elevated temperature of approximately 300° C. The predetermined temperature is 480° C. and therefore the system fluid 144 is not introduced into the thermal energy consumption system 180 and is rather directed to flow back into the main heat exchanger assembly 140, as illustrated by flowpath 250 in FIG. 1D. The system fluid 144 is heated within the main heat exchanger assembly 140 by the air to an elevated temperature of approximately 350° C. The system fluid 144, which has yet to reach the predetermined temperature, may be reintroduced into the auxiliary heat exchanger assembly 190 to flow according to the flowpath 198 shown in FIG. 1B or may be reintroduced into the reservoir 150, as shown in FIG. 1C or may be reintroduced into the main heat exchanger assembly 140, as shown in FIG. 1D. The system fluid 144 may thus circulate until the temperature of the air is heated by the concentrated solar radiation to a degree sufficient to heat the system fluid 144 to a temperature above or at the predetermined temperature. Whereupon the system fluid 144 is at or above the predetermined temperature the system fluid may be introduced into the thermal energy consumption system 180.
As described hereinabove in reference to FIGS. 1B-1D, the system fluid 144 may be reintroduced into the main heat exchanger assembly 140 wherein the system fluid 144 has failed to reach the predetermined temperature. The system fluid 144 may be reintroduced into the main heat exchanger assembly 140 via the auxiliary heat exchanger assembly 190 and reservoir 150, as shown in FIG. 1B, or via the reservoir 150, as shown in FIG. 1C, or may flow directly into the main heat exchanger assembly 140, as shown in FIG. 1D. Reintroducing the system fluid 144 into the main heat exchanger assembly 140 allows for conserving and maintaining the system fluid thermal energy within the thermal energy generation system 100, as apposed to losing the system fluid thermal energy, wherein the system fluid 144 has failed to reach the predetermined temperature. Loss of the system fluid thermal energy may be caused by discarding the system fluid 144 from the thermal energy generation system 100 or by cooling the system fluid 144 or by ceasing the operation of the thermal energy generation system 100, for example.
Reference is now made to FIGS. 2A and 2B, which are each a simplified schematic illustration of a thermal energy generation system, constructed and operative in accordance with an embodiment of the present invention, at a first and second operative mode, respectively. As seen in FIGS. 2A and 2B, a thermal energy generation system 300 comprises any suitable energy system as described hereinabove. The energy system may comprise a solar energy system, which may be any suitable solar concentrating system, such as the solar concentrating system 110 shown in FIGS. 1A-1D. The solar concentrating system 110 is operative to heat a working fluid 314, flowing within the solar concentrating system 110, by concentrated solar radiation.
The working fluid 314 may flow into a main heat exchanger assembly 340 configured for transferring heat from the working fluid 314 to a system fluid 344, flowing within the main heat exchanger assembly 340. The system fluid 344 may be any suitable fluid such as a gas, typically air, helium or carbon dioxide, or a liquid such as oil, water, an organic fluid or molten salt, for example. It is noted that the working fluid 314 may be the same as the system fluid 344. Alternatively, the working fluid 314 may be different than the system fluid 344
The system fluid 344 may flow into the main heat exchanger assembly 340 from a system fluid reservoir 350, typically in a liquid state. The system fluid 344 may be introduced into the reservoir 350 by a liquid supply line 360. Any suitable deaerator (not shown) may be provided so as to remove gases from the system fluid reservoir 350 or remove gases from any other component within the thermal energy generation system 300.
A pump 364 may be provided intermediate the reservoir 350 and the main heat exchanger assembly 340 so as to ensure the system fluid 344 continuously flows from the reservoir 350 to the main heat exchanger assembly 340.
It is noted that wherein the system fluid 344 is a gas, such as air, a blower may be provided to ensure continuous flow thereof, and wherein the system fluid 344 is a liquid, such as water, a pump, such as the pump 364, may be provided to ensure continuous flow thereof. It is further noted that additional blowers and/or pumps may be added to the thermal energy generation system 300 to ensure that the system fluid 344 and the working fluid 314 flow continuously. Additionally, some of the pumps and/or valves described herein may be obviated. The pumps and blowers may be any suitable pump and blowers known in the art.
The main heat exchanger assembly 340 may comprise a plurality of heat exchangers provided to heat the system fluid 344. In the embodiment shown in FIGS. 2A and 2B the main heat exchanger assembly 340 comprises a first heat exchanger, a second heat exchanger and a third heat exchanger. The first, second and third heat exchanger may be included in a vapor generation assembly 368 wherein the first heat exchanger may comprise a conventional preheater 370 designed to elevate the temperature of the system fluid 344 flowing therein, the second heat exchanger may comprise a vapor generator 372 configured to vaporized the system fluid 344 and/or the third heat exchanger may comprise a superheater 374 designed to further elevate the temperature of the vaporized system fluid 344.
As seen in FIG. 2A, a first operative mode is shown wherein the system fluid 344 flows along a flowpath 380. The system fluid 344 flows out of the reservoir 350 via the pump 364 and a valve 382 to the main heat exchanger assembly 340. Generally, the system fluid 344 enters the preheater 370 in a liquid state and is heated therein. Thereafter the heated system fluid 344 enters the vapor generator 372 wherein the system fluid 344 is vaporized. The vaporized system fluid 344 enters the superheater 374 wherein the vaporized system fluid 344 is further heated to the predetermined temperature.
The heated system fluid 344 flows out of the main heat exchanger assembly 340. In the first operative mode, shown in FIG. 2A, the system fluid 344 may be introduced into a thermal energy consumption system 388 via a valve 390 upon being sufficiently heated by the working fluid 314 to or above a predetermined temperature.
The thermal energy consumption system 388 is designed to utilize the thermal energy provided by the system fluid 344 wherein the system fluid 344 enters therein at or above the predetermined temperature.
The thermal energy consumption system 383 may comprise any system operative to utilize the thermal energy of the heated system fluid 344. For example, the thermal energy consumption system may comprise an industrial system. Moreover, the thermal energy provided to the thermal energy consumption system may be utilized for vaporization, pasteurization or any other thermal energy consuming process used in the chemical industry or any other industry. The thermal energy provided to the thermal energy consumption system may be used for drying, such as drying polymer containing products, for example. The thermal energy provided to the thermal energy consumption system may be used within a vapor turbine, such as a steam turbine, for generation of electricity therefrom. Additionally, the thermal energy provided to the thermal energy consumption system may be utilized to boost a vapor turbine, typically a steam turbine, such as a coal or gas fuel fired steam turbine or a steam turbine comprised in a combined cycle gas fired system. The thermal energy provided to the thermal energy consumption system may be utilized for direct heating of a solid desiccant system, such as a desiccant system comprised in an air conditioning system. Furthermore, the thermal energy provided to the thermal energy consumption system may be used for absorption cooling.
Residual thermal energy exiting the thermal energy consumption system 388, following consumption of the thermal energy within the thermal energy consumption system 388, may be further used within any other thermal energy consumption system or alternatively may be introduced back into the thermal energy generation system 300.
Turning to FIG. 2B, a second operative mode is shown wherein the temperature of the system fluid 344 flowing out of the main heat exchanger assembly 340 is less than the predetermined temperature.
The system fluid 344 may fail to reach the predetermined temperature prior to entering the thermal energy consumption system 388 at times the concentrated solar radiation may be insufficient to heat the working fluid 314 to a desired temperature capable for heating the system fluid 344 to the predetermined temperature. Insufficient concentrated solar radiation may typically occur during early morning, evening and nighttime.
The system fluid 344 may be directed to enter a thermal energy conservation assembly 391. The thermal energy conservation assembly 391 is provided for conserving the thermal energy of the system fluid 344, by reintroducing the system fluid 344 into the main heat exchanger assembly 340. As seen in FIG. 2B, the thermal energy conservation assembly 391 may comprise an auxiliary heat exchanger assembly 392 designated to reintroduce the system fluid 344 into the main heat exchanger assembly 340.
The system fluid 344 may be directed to enter the auxiliary heat exchanger assembly 392, via the valves 390 and 396 along a flowpath 398.
The auxiliary heat exchanger assembly 392 may comprise a plurality of heat exchangers, such as a first auxiliary heat exchanger 404, placed intermediate the superheater 374 and the vapor generator 372, a second auxiliary heat exchanger 408, placed intermediate the vapor generator 372 and the preheater 370 and a third auxiliary heat exchanger 410, placed intermediate the preheater 370 and the reservoir 350.
Each of the first, second and third auxiliary heat exchanger 404, 408 and 410, respectively, may comprise a heat providing fluid volume 420 and a heat receiving fluid volume 430. The system fluid 344 flowing within the heat providing fluid volume 420 heats the system fluid 344 flowing within the corresponding heat receiving fluid volume 430.
The system fluid 344 may be directed to enter the auxiliary heat exchanger assembly 392 at the heat providing fluid volume 420 of the first auxiliary heat exchanger 404, wherein the system fluid 344 heats the system fluid 344 flowing in the corresponding receiving fluid volume 430, as will be described hereinbelow.
The system fluid may flow from the heat providing fluid volume 420 of the first auxiliary heat exchanger 404, via a valve 440, to the heat providing fluid volume 420 of the second auxiliary heat exchanger 408, wherein the system fluid 344 heats the system fluid 344 flowing in the corresponding receiving fluid volume 430.
The system fluid may flow from the heat providing fluid volume 420 of the second auxiliary heat exchanger 408, via valves 442 and 444, to the heat providing fluid volume 420 of the third auxiliary heat exchanger 410, wherein the system fluid 344 heats the system fluid 344 flowing in the corresponding receiving fluid volume 430.
Thereafter system fluid 344 may flow from the heat providing fluid volume 420 of the third auxiliary heat exchanger 410 to the reservoir 350.
Alternatively, the system fluid 344 may bypass any one of the first, second or third auxiliary heat exchangers 404, 408 and 410, respectively. As seen in FIG. 2B, the system fluid 344 exiting the main heat exchanger assembly 340 may bypass the first auxiliary heat exchanger 404 via the valves 390, 396 and 450. The system fluid 344 may enter the second auxiliary heat exchanger 408 via the valve 440 or may enter the third auxiliary heat exchanger 410 via the valves 442 and 444.
The system fluid 344 exiting the first auxiliary heat exchanger 404 may bypass the second auxiliary heat exchanger 408 via the valves 440, 450, 442 and 444. The system fluid 344 may enter the third auxiliary heat exchanger 410 or may enter the reservoir 350.
The system fluid 344 exiting the second auxiliary heat exchanger 408 may bypass the third auxiliary heat exchanger 410 via the valves 442 and 444 and enter the reservoir 350.
The system fluid 344 may enter the reservoir 350 via a valve 460 and a pump 462 wherein the pressure of the system fluid 344 is less than the pressure of the liquid within reservoir 350. Alternatively, the system fluid 344 may flow to the reservoir 350 via the valve 460 and a valve 468, which the valve 468 may be an expansion valve, wherein the pressure of the system fluid 344 is greater than the pressure of the liquid within reservoir 350.
The liquid supply line 360 may be shut. Shutting the liquid supply line 360 may allow controlling the pressure degree of the liquid within the reservoir 350. Alternatively, the liquid supply line 360 may be partially or fully open and new liquid may be introduced into the reservoir 350. Partially or fully opening the liquid supply line 360 may allow controlling the pressure degree of the liquid within the reservoir 350 and/or may allow for additional system fluid 344 to be introduced into the thermal energy generation system 300 for consumption by the thermal energy consumption system 388.
The system fluid 344 exiting the reservoir 350 may enter the heat receiving fluid volume 430 within the third auxiliary heat exchanger 410, via the pump 364 and the valve 382. The system fluid 344 is heated therein by the system fluid 344 flowing within the corresponding heat providing fluid volume 420 of the third auxiliary heat exchanger 410.
The heated system fluid 344 may exit the heat receiving fluid volume 430 of the third auxiliary heat exchanger 410 and flow into the preheater 370 for further heating thereof. The system fluid 344 may flow from the preheater 370, via a valve 470 to the heat receiving fluid volume 430 within the second auxiliary heat exchanger 408. The system fluid 344 is heated therein by the system fluid 344 flowing within the corresponding heat providing fluid volume 420 of the second auxiliary heat exchanger 408.
The heated system fluid 344 may exit the heat receiving fluid volume 430 of the second auxiliary heat exchanger 408 and flow into the vapor generator 372 for vaporization thereof. The system fluid 344 may flow from the vapor generator 372, via a valve 474 to the heat receiving fluid volume 430 within the first auxiliary heat exchanger 404. The system fluid 344 is heated therein by the system fluid 344 flowing within the corresponding heat providing fluid volume 420 of the first auxiliary heat exchanger 404.
The heated system fluid 344 may exit the heat receiving fluid volume 430 of the first auxiliary heat exchanger 404 and flow into the superheater 374 for further heating thereof.
As described hereinabove, the system fluid 344 may bypass any one of the first, second or third auxiliary heat exchangers 404, 408 and 410, respectively. As seen in FIG. 2B, the system fluid 344 exiting the reservoir 350 may bypass the third auxiliary heat exchanger 410 via the valve 382 and enter the preheater 370. The system fluid 344 may bypass the third auxiliary heat exchanger 410 and enter the preheater 370 wherein the temperature of the working fluid 314 is heated by the concentrated solar radiation to a degree sufficient to heat the system fluid 344 to a temperature above or at the predetermined temperature.
The system fluid 344 exiting the preheater 370 may bypass the second auxiliary heat exchanger 408 via the valve 470 and enter the vapor generator 372. The system fluid 344 may bypass the second auxiliary heat exchanger 408 and enter the vapor generator 372 wherein the temperature of the working fluid 314 is heated by the concentrated solar radiation to a degree sufficient to heat the system fluid 344 to a temperature above or at the predetermined temperature.
The system fluid 344 exiting the vapor generator 372 may bypass the first auxiliary heat exchanger 404 via the valve 474 and enter the superheater 374. The system fluid 344 may bypass the first auxiliary heat exchanger 404 and enter the superheater 374 wherein the temperature of the working fluid 314 is heated by the concentrated solar radiation to a degree sufficient to heat the system fluid 344 to a temperature above or at the predetermined temperature.
It is appreciated that a portion of the system fluid 344 may enter any one of the first, second or third auxiliary heat exchangers 404, 408 and 410, respectively or the preheater 370, vapor generator 372 or the superheater 374 while other portions of the system fluid 344 may enter any one of the first, second or third auxiliary heat exchangers 404, 408 and 410, respectively or the preheater 370, vapor generator 372 or the superheater 374.
Upon heating the system fluid 344 within the superheater 374 of the main heat exchanger assembly 340, the system fluid 344 may enter the thermal energy consumption system 388 wherein the system fluid 344 temperature is at or above the predetermined temperature, as shown in FIG. 2A. Wherein the system fluid 344 temperature is less than the predetermined temperature the system fluid 344 may be reintroduced into any one of the first, second or third auxiliary heat exchangers 404, 408 and 410, respectively, to follow flowpath 398, as shown in FIG. 2B.
As described hereinabove in reference to FIGS. 2A and 2B, the system fluid 344 may be reintroduced into the main heat exchanger assembly 340 wherein the system fluid 344 has failed to reach the predetermined temperature. The system fluid 344 may be reintroduced into the main heat exchanger assembly 340 via any one of the first, second or third auxiliary heat exchangers 404, 408 and 410, respectively, and reservoir 350, as shown in FIG. 2B. Reintroducing the system fluid 344 into the main heat exchanger assembly 340 allows for conserving and maintaining the system fluid thermal energy within the thermal energy generation system 300, as apposed to losing the system fluid thermal energy, wherein the system fluid 344 has failed to reach the predetermined temperature. Loss of the system fluid thermal energy may be caused by discarding the system fluid 344 out of the thermal energy generation system 300 or by cooling the system fluid 344 or by ceasing the operation of the thermal energy generation system 300, for example.
Introducing the system fluid 344 into any one of the first, second or third auxiliary heat exchangers 404, 408 and 410, respectively, allows for minimizing a decrease in the system fluid temperature which would have occurred had the system fluid 344 been directed to flow from the reservoir 350 directly into the preheater 370, or directly from the preheater 370 to the vapor generator 372 or directly from the vapor generator 372 to the superheater 374. This is in virtue of the transfer of heat from the system fluid 344, flowing in the heat providing fluid volume 420, to the system fluid 344, flowing within the heat receiving fluid volume 430 of the first, second and third auxiliary heat exchanger 404, 408 and 410, respectively
The main heat exchanger assembly 340 and the auxiliary heat exchanger assembly 392 may each comprise additional heat exchangers.
The main heat exchanger assembly 340 and the first, second and third auxiliary heat exchangers 404, 408 and 410, respectively, of the auxiliary heat exchanger assembly 392 may comprise any suitable configuration allowing a fluid to be heated therein, such as a shell and tube heat exchanger, a plate heat exchanger, or any other suitable configuration.
It is appreciated that the thermal energy generation system 300 may comprise any suitable heating element operative to heat a fluid flowing within the thermal energy generation system 300. Additionally, the thermal energy generation system 300 may comprise any suitable thermal energy storage device for storing thermal energy generated by the thermal energy generation system 300. Moreover, the thermal energy generation system 300 may comprise any suitable vapor storage device, such as a vapor drum described in reference to FIGS. 3A and 3B hereinblow.
It is appreciated that any one of the first, second and third auxiliary heat exchanger 404, 408 and 410, respectively may be integrated with any one of the preheater 370, the vapor generator 372 and/or the superheater 374, such as in a tube and shell heat exchanger configuration.
Other features and advantages of the present invention are apparent from the different examples. The provided examples illustrate different components and methodology useful in practicing the present invention. The examples do not limit the claimed invention. Based on the present disclosure the skilled artisan can identify and employ other components and methodology useful for practicing the present invention.
The following non-limiting example describes the embodiment shown in FIGS. 2A and 2B, at a discrete point in time during the operation of the thermal energy generation system 300. The working fluid 314 may be air which enters the receiver 320 at a temperature of approximately 50° C. The air is heated by concentrated solar radiation to a temperature of approximately 400° C. The heated air enters the main heat exchanger assembly 340. The system fluid 344 may be water which flows out of the reservoir 350 at a temperature of approximately 20° C. into the preheater 370 of the main heat exchanger assembly 340, following flowpath 380, shown in FIG. 2A. The system fluid 344 is heated within the preheater 370 by the heated air and exits therefrom at an elevated temperature of approximately 70° C. The system fluid 344 flows into the vapor generator 372, which may be configured as a conventional steam generator, and is vaporized therein to steam. The steam flows out of the vapor generator 372 at an elevated temperature of approximately 160° C. and flows into the superheater 374 for further heating thereof. The system fluid exits the superheater 374 at an elevated temperature of approximately 300° C.
The predetermined temperature is 450° C. and therefore the system fluid 344 is not introduced into the thermal energy consumption system 388 and is rather directed to flow into the heat providing fluid volume 420 of the first auxiliary heat exchanger 404, as illustrated by flowpath 398 in FIG. 2B. The system fluid 344 exits the heat providing fluid volume 420 of the first auxiliary heat exchanger 404 at a reduced temperature of approximately 200° C., following transfer of thermal energy therefrom to a corresponding system fluid 344 flowing within the heat receiving fluid volume 430 of the first auxiliary heat exchanger 404.
The system fluid 344 enters the heat providing fluid volume 420 of the second auxiliary heat exchanger 408. The system fluid 344 exits the heat providing fluid volume 420 of the second auxiliary heat exchanger 408 at a reduced temperature of approximately 100° C., following transfer of thermal energy therefrom to a corresponding system fluid 344 flowing within the heat receiving fluid volume 430 of the second auxiliary heat exchanger 408.
The system fluid 344 enters the heat providing fluid volume 420 of the third auxiliary heat exchanger 410. The system fluid 344 exits the heat providing fluid volume 420 of the third auxiliary heat exchanger 410 at a reduced temperature of approximately 50° C., following transfer of thermal energy therefrom to a corresponding system fluid 344 flowing within the heat receiving fluid volume 430 of the third auxiliary heat exchanger 410.
Thereafter, the system fluid 344 flows from the heat providing fluid volume 420 of the third auxiliary heat exchanger 410 to the reservoir 350, wherein the reservoir water is at a temperature of approximately 20° C. The system fluid 344 flows from the reservoir 350 to the heat receiving fluid volume 430 of the third auxiliary heat exchanger 410 at a temperature of approximately 40° C. The system fluid 344 flows out of the heat receiving fluid volume 430 of the third auxiliary heat exchanger 410 at an elevated temperature of approximately 70° C. and enters the preheater 370. The system fluid 344 exits the preheater 370 at an elevated temperature of approximately 90° C. and enters the heat receiving fluid volume 430 of the second auxiliary heat exchanger 408. The system fluid 344 flows out of the heat receiving fluid volume 430 of the second auxiliary heat exchanger 408 at an elevated temperature of approximately 110° C. and enters the vapor generator 372. The now steamed system fluid 344 exits the vapor generator 372 at an elevated temperature of approximately 160° C. and enters the heat receiving fluid volume 430 of the first auxiliary heat exchanger 404. The system fluid 344 flows out of the heat receiving fluid volume 430 of the first auxiliary heat exchanger 404 at an elevated temperature of approximately 250° C. and enters the superheater 374. The system fluid 344 exits the superheater 374 at an elevated temperature of approximately 380° C.
The system fluid 344, which has yet to reach the predetermined temperature, may be reintroduced into the auxiliary heat exchanger assembly 392 to flow according to flowpath 398 shown in FIG. 2B. The system fluid 344 may thus circulate until the temperature of the air is heated by the concentrated solar radiation to a degree sufficient to heat the system fluid to a temperature above or at the predetermined temperature. Whereupon the system fluid 344 is at or above the predetermined temperature the system fluid may be introduced into the thermal energy consumption system 388.
Reference is now made to FIGS. 3A and 3B, which are each a simplified schematic illustration of a thermal energy generation system, constructed and operative in accordance with yet another embodiment of the present invention, at a first and second operative mode, respectively. As seen in FIGS. 3A and 3B, a thermal energy generation system 500 is comprised mainly of the components of thermal energy generation system 300 of FIGS. 2A and 2B, albeit a vapor drum 510 which may be an alternative to the second auxiliary heat exchanger 408 of FIGS. 2A and 2B. It is noted that the drum 510 may be provided in addition to the second auxiliary heat exchanger 408.
The vapor drum 510 may be any conventional vapor drum comprising a vapor drum reservoir 520, typically including a drum liquid therein. The drum 510 is in fluid communication with the vapor generator 372 via tubes 528. The drum liquid may be vaporized by heat provided by the vapor generator 372. The drum vapor may rise to a top portion 530 of the drum 510.
The vapor generator 372 may be configured in any suitable configuration, such as a multiplicity of tubes (not shown) designated to be heated by the working fluid 314 flowing within a main heat exchanger assembly 540, thereby providing heat for vaporizing the drum liquid.
The drum 510 allows for storing a relatively large volume of vapor within the drum reservoir 520 wherein the vapor is generated therein.
As seen in FIG. 3A, a first operative mode is shown wherein the system fluid 344 flows along a flowpath 580. The system fluid 344 flows out of the reservoir 350 via the pump 364 and the valve 382 to the main heat exchanger assembly 540. Generally, the system fluid 344 enters the preheater 370 in a liquid state and is heated therein. Thereafter the heated system fluid 344 enters the drum reservoir 520 and is vaporized along with the drum liquid by heat provided by the vapor generator 372. The vaporized system fluid 344, which now includes the drum vapor, rises to the top portion 530 of the drum 510. The vaporized system fluid 344 enters the superheater 374 wherein the vaporized system fluid 344 is further heated to the predetermined temperature.
The heated system fluid 344 flows out of the main heat exchanger assembly 540. In the first operative mode, shown in FIG. 3A, the system fluid 344 may be introduced into the thermal energy consumption system 388 via the valve 390 upon being sufficiently heated by the working fluid 314 to or above a predetermined temperature.
Turning to FIG. 3B, a second operative mode is shown wherein the temperature of the system fluid 344 flowing out of the main heat exchanger assembly 540 is less than the predetermined temperature.
The system fluid 344 may be directed to enter a thermal energy conservation assembly 584. The thermal energy conservation assembly 584 is provided for conserving the thermal energy of the system fluid 344, by reintroducing the system fluid 344 into the main heat exchanger assembly 540. As seen in FIG. 3B, the thermal energy conservation assembly 584 may comprise an auxiliary heat exchanger assembly 592 designated to reintroduce the system fluid 344 into the main heat exchanger assembly 540.
The system fluid 344 may be directed to enter the auxiliary heat exchanger assembly 592, via the valves 390 and 396 along a flowpath 598.
The auxiliary heat exchanger assembly 592 may comprise a plurality of heat exchangers, such as a primary auxiliary heat exchanger 604, placed intermediate the superheater 374 and the vapor generator 372 and a secondary auxiliary heat exchanger 610, placed intermediate the preheater 370 and the reservoir 350. The primary auxiliary heat exchanger 604 may be similar to the first auxiliary heat exchanger 404 of FIGS. 2A and 2B and the secondary auxiliary heat exchanger 610 may be similar to the third auxiliary heat exchanger 410 of FIGS. 2A and 2B.
The system fluid 344 may be directed to enter the auxiliary heat exchanger assembly 592 at a heat providing fluid volume 620 of the primary auxiliary heat exchanger 604, wherein the system fluid 344 heats the system fluid 344 flowing in a corresponding receiving fluid volume 630, as will be described hereinbelow.
The system fluid 344 may flow from the heat providing fluid volume 620 of the primary auxiliary heat exchanger 604, via the valve 440, to the drum reservoir 520, so as to heat the drum liquid within the drum reservoir 520 along with the system fluid 344 flowing therein from the preheater 370.
The system fluid 344 may flow from the drum 510, via the valves 442 and 444, to the heat providing fluid volume 620 of the secondary auxiliary heat exchanger 610, wherein the system fluid 344 heats the system fluid 344 flowing in the corresponding receiving fluid volume 630.
Thereafter, the system fluid 344 may flow from the heat providing fluid volume 620 of the secondary auxiliary heat exchanger 610 to the reservoir 350.
Alternatively, the system fluid 344 may bypass the primary or secondary auxiliary heat exchangers 604 or 610, respectively. As seen in FIG. 3B, the system fluid 344 exiting the main heat exchanger assembly 540 may bypass the primary auxiliary heat exchanger 604 via the valves 390, 396 and 450. The system fluid 344 may enter the drum 510 via the valve 440 or may enter the secondary auxiliary heat exchanger 610 via the valves 442 and 444.
The system fluid 344 exiting the primary auxiliary heat exchanger 604 may bypass the drum 510 via the valves 440, 450, 442 and 444. The system fluid 344 may enter the secondary auxiliary heat exchanger 610 or may enter the reservoir 350.
The system fluid 344 exiting the drum 510 may bypass the secondary auxiliary heat exchanger 610 and may enter the reservoir 350.
As described hereinabove, the system fluid 344 may enter the reservoir 350 via the valve 460 and the pump 462 wherein the pressure of the system fluid 344 is less than the pressure of the liquid within reservoir 350. Alternatively, the system fluid 344 may flow to the reservoir 350 via the valve 460 and the valve 468, which valve 468 may be an expansion valve, wherein the pressure of the system fluid 344 is greater than the pressure of the liquid within reservoir 350.
The liquid supply line 360 may be shut or alternatively, the liquid supply line 360 may be fully or partially open and new liquid may be introduced into reservoir 350.
The system fluid 344 exiting the reservoir 350 may enter the heat receiving fluid volume 430 within the secondary auxiliary heat exchanger 610, via the pump 364 and the valve 382. The system fluid 344 is heated therein by the system fluid 344 flowing within the corresponding heat providing fluid volume 420 of the secondary auxiliary heat exchanger 610.
The heated system fluid 344 may exit the heat receiving fluid volume 630 of the secondary auxiliary heat exchanger 610 and flow into the preheater 370 for further heating thereof. The system fluid 344 may flow from the preheater 370 to the drum 510. The system fluid 344 and drum liquid is heated therein by the corresponding system fluid 344 flowing therein via the valve 440.
The heated system fluid 344 may exit the drum 510 and flow via the valve 474 to the heat receiving fluid volume 430 within the primary auxiliary heat exchanger 604. The system fluid 344 is heated therein by the system fluid 344 flowing within the corresponding heat providing fluid volume 420 of the primary auxiliary heat exchanger 604.
The heated system fluid 344 may exit the heat receiving fluid volume 430 of the primary auxiliary heat exchanger 604 and flow into the superheater 374 for further heating thereof.
As described hereinabove, the system fluid 344 may bypass any one of the primary or secondary auxiliary heat exchangers 604 and 610, respectively. As seen in FIG. 3B, the system fluid 344 exiting the reservoir 350 may bypass the secondary auxiliary heat exchanger 610 via the valve 382 and enter the preheater 370. The system fluid 344 may bypass the secondary auxiliary heat exchanger 610 and enter the preheater 370 wherein the temperature of the working fluid 314 is heated by the concentrated solar radiation to a degree sufficient to heat the system fluid 344 to a temperature above or at the predetermined temperature.
The system fluid 344 exiting the drum 510 may bypass the primary auxiliary heat exchanger 604 via the valve 474 and enter the superheater 374.
The system fluid 344 may bypass the primary auxiliary heat exchanger 604 and enter the superheater 374 wherein the temperature of the working fluid 314 is heated by the concentrated solar radiation to a degree sufficient to heat the system fluid 344 to a temperature above or at the predetermined temperature.
It is appreciated that a portion of the system fluid 344 may enter any one of the primary or secondary auxiliary heat exchangers 604 and 610, respectively, or the preheater 370, vapor generator 372 or the superheater 374 while other portions of the system fluid 344 may enter any one of the primary or secondary auxiliary heat exchangers 604 and 610, respectively or the preheater 370, vapor generator 372 or the superheater 374.
Upon heating the system fluid 344 within the superheater 374 of the main heat exchanger assembly 540, the system fluid 344 may enter the thermal energy consumption system 388 wherein the system fluid 344 temperature is at or above the predetermined temperature, as shown in FIG. 3A. Wherein the system fluid temperature is less than the predetermined temperature the system fluid 344 may be reintroduced into any one of the primary or secondary auxiliary heat exchangers 604, and 610, respectively, or drum 510 to follow flowpath 598, as shown in FIG. 2B.
As described hereinabove in reference to FIGS. 3A and 3B, the system fluid 344 may be reintroduced into the main heat exchanger assembly 540 wherein the system fluid 344 has failed to reach the predetermined temperature. The system fluid 344 may be reintroduced into the main heat exchanger assembly 540 via any one of the primary or secondary auxiliary heat exchangers 604, and 610, respectively, drum 510 and reservoir 350, as shown in FIG. 3B. Reintroducing the system fluid 344 into the main heat exchanger assembly 540 allows for conserving and maintaining the system fluid thermal energy within the thermal energy generation system 500, as apposed to losing the system fluid thermal energy, wherein the system fluid 344 has failed to reach the predetermined temperature. Loss of the system fluid thermal energy may be caused by discarding the system fluid 344 out of the thermal energy generation system 500 or by cooling the system fluid 344 or by ceasing the operation of the thermal energy generation system 500, for example.
Introducing the system fluid 344 into any one of the primary or secondary auxiliary heat exchangers 604, and 610, respectively, or drum 510, allows for minimizing a decrease in the system fluid temperature which would have occurred had the system fluid 344 been directed to flow from the reservoir 350 directly into the preheater 370, or directly from the preheater 370 to the vapor generator 372 or directly from the vapor generator 372 to the superheater 374. This is in virtue of the transfer of heat from the system fluid 344, flowing in the heat providing fluid volume 620, to the system fluid 344 flowing within the heat receiving fluid volume 630 of the primary or secondary auxiliary heat exchangers 604, and 610, respectively, or in virtue of the transfer of heat from the system fluid 344 flowing in the drum 510 via valve 440 to the system fluid 344 flowing within the drum 510 from the preheater 370.
The main heat exchanger assembly 540 and the auxiliary heat exchanger assembly 592 may each comprise additional heat exchangers.
The main heat exchanger assembly 540 and the primary or secondary auxiliary heat exchangers 604, and 610, respectively, of the auxiliary heat exchanger assembly 592 may comprise any suitable configuration allowing a fluid to be heated therein, such as a shell and tube heat exchanger, a plate heat exchanger, or any other suitable configuration.
It is appreciated that the thermal energy generation system 500 may comprise any suitable heating element operative to heat a fluid flowing within the thermal energy generation system 500. Additionally, the thermal energy generation system 500 may comprise any suitable thermal energy storage device for storing thermal energy generated by the thermal energy generation system 500. Moreover, the thermal energy generation system 500 may comprise any suitable vapor storage device, such as the vapor drum 510.
It is noted that additional pumps, blowers and/or valves may be utilized in the thermal energy generation system 500. Additionally, some of the pumps and/or valves described herein may be obviated.
Other features and advantages of the present invention are apparent from the different examples. The provided examples illustrate different components and methodology useful in practicing the present invention. The examples do not limit the claimed invention. Based on the present disclosure the skilled artisan can identify and employ other components and methodology useful for practicing the present invention.
The following non-limiting example describes the embodiment shown in FIGS. 3A and 3B, at a discrete point in time during the operation of the thermal energy generation system 500. The working fluid 314 may be air which enters the receiver 120 at a temperature of approximately 50° C. The air is heated by concentrated solar radiation to a temperature of approximately 400° C. The heated air enters the main heat exchanger assembly 540. The system fluid 344 may be water which flows out of the reservoir 350 at a temperature of approximately 20° C. into the preheater 370 of the main heat exchanger assembly 540, following flowpath 580, shown in FIG. 3A. The system fluid 344 is heated within the preheater 370 by the heated air and exits therefrom at an elevated temperature of approximately 70° C. The system fluid 344 flows into the drum reservoir 520 wherein the drum liquid is water.
The system fluid 344 flows within the drum 510 so as to heat the drum water within the drum reservoir 520 along with the system fluid 344 flowing therein from the preheater 370. The system fluid 344 is vaporized along with the drum water by heat provided by the vapor generator 372. The resultant steamed system fluid 344, which now includes the drum vapor, rises to the top portion 530 of the drum 510. The steamed system fluid 344 enters the superheater 374 at an elevated temperature of approximately 160° C. for further heating thereof. The system fluid 344 exits the superheater 374 at an elevated temperature of approximately 300° C.
The predetermined temperature is 450° C. and therefore the system fluid 344 is not introduced into the thermal energy consumption system 388 and is rather directed to flow into the heat providing fluid volume 620 of the primary auxiliary heat exchanger 604, as illustrated by flowpath 598 in FIG. 3B. The system fluid 344 exits the heat providing fluid volume 620 of the primary auxiliary heat exchanger 604 at a reduced temperature of approximately 200° C., following transfer of thermal energy therefrom to a corresponding system fluid 344 flowing within the heat receiving fluid volume 630 of the primary auxiliary heat exchanger 604.
The system fluid 344 enters the drum reservoir 520 so as to heat the drum water within the drum reservoir 520 along with the system fluid 344 flowing therein from the preheater 370. The system fluid 344 exits the drum 510 at a reduced temperature of approximately 100° C.
The system fluid 344 enters the heat providing fluid volume 620 of the secondary auxiliary heat exchanger 610. The system fluid 344 exits the heat providing fluid volume 620 of the secondary auxiliary heat exchanger 610 at a reduced temperature of approximately 50° C., following transfer of thermal energy therefrom to a corresponding system fluid 344 flowing within the heat receiving fluid volume 630 of the secondary auxiliary heat exchanger 610.
Thereafter, the system fluid 344 flows from the heat providing fluid volume 620 of the secondary auxiliary heat exchanger 610 to the reservoir 350, wherein the reservoir water is at a temperature of approximately 20° C. The system fluid 344 flows from the reservoir 350 to the heat receiving fluid volume 630 of the secondary auxiliary heat exchanger 610 at a temperature of approximately 40° C. The system fluid 344 flows out of the heat receiving fluid volume 630 of the secondary auxiliary heat exchanger 610 at an elevated temperature of approximately 70° C. and enters the preheater 370. The system fluid 344 exits the preheater 370 at an elevated temperature of approximately 90° C. and enters the drum 510. The system fluid 344 and the drum water are heated therein by the corresponding system fluid 344 flowing therein via the valve 440. The resultant steamed system fluid 344, which now includes the drum steam, flows out of the drum 510 at an elevated temperature of approximately 160° C. and enters the heat receiving fluid volume 630 of the primary auxiliary heat exchanger 604. The system fluid 344 flows out of the heat receiving fluid volume 630 of the primary auxiliary heat exchanger 604 at an elevated temperature of approximately 250° C. and enters the superheater 374. The system fluid 344 exits the superheater 374 at an elevated temperature of approximately 380° C.
The system fluid 344, which has yet to reach the predetermined temperature, may be reintroduced into the auxiliary heat exchanger assembly 592 to flow according to the flowpath 598 shown in FIG. 3B. The system fluid 344 may thus circulate until the temperature of the air is heated by the concentrated solar radiation to a degree sufficient to heat the system fluid to a temperature above or at the predetermined temperature. Whereupon the system fluid 344 is at or above the predetermined temperature the system fluid may be introduced into the thermal energy consumption system 388.
It will be appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described herein above. Rather the scope of the present invention includes both combinations and subcombinations of the various features described hereinabove as well as variations and modifications which would occur to persons skilled in the art upon reading the specifications and which are not in the prior art.

Claims

1-31. (canceled)

32. A thermal energy generation system having a working fluid and a system fluid, comprising:

an energy system for heating the working fluid by applying heat thereto;

a main heat exchanger assembly for transferring heat from the working fluid to the system fluid;

a thermal energy consumption system for receiving the heated system fluid from said main heat exchanger assembly when the temperature of the system fluid is at or above a predetermined temperature; and

a thermal energy conservation assembly for receiving the heated system fluid from said main heat exchanger assembly and for reintroducing the system fluid thereto when the temperature of the system fluid is less than said predetermined temperature.

33. A thermal energy generation system according to claim 32 wherein said thermal energy conservation assembly is provided for conserving said thermal energy provided by the system fluid within said thermal energy generation system.

34. A thermal energy generation system according to claim 32 wherein said energy system is selected from the group consisting of: a fossil-fuel based energy system, an electrical power energy system, a renewable energy system, a geothermal energy system, a wind energy system, a wave energy system, a solar energy system, a solar concentrating system, a solar tower energy system, a Fresnel lens solar energy system, a trough-Fresnel mirror solar energy system, a linear Fresnel solar energy system, a solar heliostat concentrating energy system and a parabolic trough solar concentrating energy system.

35. A thermal energy generation system according to claim 32 wherein the working fluid is heated by solar radiation applied thereto following concentration of said solar radiation by a dish.

36. A thermal energy generation system according to claim 32 wherein said working fluid is heated within a solar receiver by solar radiation impinging thereupon.

37. A thermal energy generation system according to claim 32 wherein said thermal energy conservation assembly comprises an auxiliary heat exchanger assembly including at least one auxiliary heat exchanger in fluid communication with said main heat exchanger assembly, said at least one auxiliary heat exchanger including:

a heat providing fluid volume for providing the system fluid to the auxiliary heat exchanger assembly when the temperature of the system fluid is less than said predetermined temperature; and

a heat receiving fluid volume, wherein the system fluid flowing therein is heated by the system fluid flowing within said heat providing fluid volume, and for reintroducing the heated system fluid to said main heat exchanger assembly.

38. A thermal energy generation system according to claim 32 wherein the system fluid flows into said main heat exchanger assembly from a system fluid reservoir.

39. A thermal energy generation system according to claim 38 wherein the system fluid is reintroduced into said main heat exchanger assembly via said system fluid reservoir, wherein the temperature of the system fluid is less than said predetermined temperature.

40. A thermal energy generation system according to claim 32 wherein the system fluid is reintroduced into said main heat exchanger assembly via conduits, wherein the temperature of the system fluid is less than said predetermined temperature.

41. A thermal energy generation system according to claim 32 wherein said main heat exchanger assembly comprises any one of:

a preheater provided to heat the system fluid flowing therein by said heat transferred by the working fluid;

a vapor generator provided to vaporize the system fluid flowing therein from said preheater by said heat transferred by the working fluid; and

a superheater provided to heat the system fluid flowing therein from said vapor generator by said heat transferred by the working fluid.

42. A thermal energy generation system according to claim 41 wherein a vapor drum is in fluid communication with said vapor generator.

43. A thermal energy generation system according to claim 32 and comprising a vapor storage device for storing vaporized said system fluid.

44. A thermal energy generation system having a working fluid and a system fluid, comprising:

a solar energy system for heating the working fluid by applying solar radiation thereto;

an auxiliary heat exchanger assembly including at least one auxiliary heat exchanger in fluid communication with said main heat exchanger assembly, said at least one auxiliary heat exchanger including:

a heat providing fluid volume for providing the system fluid to said auxiliary heat exchanger assembly when the temperature of the system fluid is less than said predetermined temperature; and

45. A thermal energy generation system according to claim 44 wherein said solar energy system comprises a solar concentrating system operative to heat said working fluid by concentrated solar radiation.

46. A thermal energy generation system according to claim 44 wherein said main heat exchanger assembly comprises any one of:

47. A thermal energy generation system according to claim 44 and comprising a vapor storage device for storing vaporized said system fluid.

48. A thermal energy generation system according to claim 47 wherein said vapor storage device comprises a vapor drum designed to store vaporized said system fluid.

49. A thermal energy generation system according to claim 48 wherein said vapor drum is heated by said vapor generator.

50. A thermal energy generation system having a working fluid and a system fluid, comprising:

a system fluid reservoir for storing the system fluid;

a main heat exchanger assembly for receiving the system fluid from the reservoir, for receiving the working fluid from the solar energy system, and for transferring heat therebetween, wherein the main heat exchanger assembly includes any one of:

a preheater for heating said system fluid, by said heat transferred thereto by the working fluid;

a vapor generator for receiving the system fluid from said preheater and for vaporizing the system fluid by said heat transferred thereto by the working fluid therein; and

a superheater for receiving the system fluid from said vapor generator and for transferring heat to the system fluid from the working fluid;

a thermal energy consumption system for receiving the heated system fluid from said superheater when the temperature of the system fluid is at or above a predetermined temperature; and

an auxiliary heat exchanger assembly including at least one auxiliary heat exchanger in fluid communication with any one of said preheater, said vapor generator, said superheater and said system fluid reservoir, said at least one auxiliary heat exchanger including:

a heat providing fluid volume for providing the system fluid to the auxiliary heat exchanger assembly when the temperature of the system fluid is less than said predetermined temperature and providing the system fluid to the system fluid reservoir; and

a heat receiving fluid volume, wherein the system fluid flowing therein from said system fluid reservoir is heated by the system fluid flowing within said heat providing fluid volume, and for reintroducing the heated system fluid to any one of said preheater, said vapor generator, said superheater and said system fluid reservoir.

51. A method for generating thermal energy comprising:

heating a working fluid by impingement of solar radiation thereon;

transferring heat from said working fluid to a system fluid flowing within a main heat exchanger assembly;

utilizing thermal energy provided by heat within said system fluid to operate a thermal energy consumption system, wherein said system fluid enters therein from said main heat exchanger assembly at or above a predetermined temperature; and

reintroducing said system fluid into said main heat exchanger assembly, wherein the temperature of said system fluid is less than said predetermined temperature.