WO2006098558A1

WO2006098558A1 - Heat-absorption-type power generation system

Info

Publication number: WO2006098558A1
Application number: PCT/KR2006/000734
Authority: WO
Inventors: Se-Il Oh
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-03-15
Filing date: 2006-03-03
Publication date: 2006-09-21
Anticipated expiration: 2007-09-15
Also published as: KR100658321B1; KR20060099901A

Abstract

The present invention provides a heat-absorption-type power generation system, in which a first thermal medium of an external circulation cycle absorbs external heat while it passes through a heat absorption unit, exchanges heat with a second thermal medium flowing in an internal circulation cycle while the first thermal medium flows in the direction opposite the flowing direction of the second thermal medium of the internal circulation cycle, and generates power when the first thermal medium, having absorbed heat, expands in an expansion unit. The power generation system includes an external circulation cycle (10) having an expansion unit (11) for generating power, with a first thermal medium flowing in the external circulation cycle; an internal circulation cycle (20) arranged inside the external circulation cycle, with a second thermal medium flowing in the internal circulation cycle in the direction opposite the flowing direction of the first thermal medium; and a heat absorption unit (H3) to transfer heat of an external fluid to the first thermal medium of the external circulation cycle. In the power generation system, the first thermal medium exchanges heat with the second thermal medium in both a first heat exchanging unit (Hl) and a second heat exchanging unit (H2).

Description

HEAT-ABSORPTION-TYPE POWER GENERATION SYSTEM

Technical Field

[1] The present invention relates to heat- absorption-type power generation systems and, more particularly, to a heat-absorption-type power generation system, in which a first thermal medium of an external circulation cycle absorbs external heat while it passes through a heat absorption unit, exchanges heat with a second thermal medium flowing in an internal circulation cycle while the first thermal medium flows in the direction opposite the flowing direction of the second thermal medium of the internal circulation cycle, and which generates power when the first thermal medium, which has absorbed heat, expands in an expansion unit. Background Art

[2] Korean Patent Application No. 1986-0010374 filed on December 4, 1986 discloses a "Device for Converting Heat to Power".

[3] The power generation device for converting heat to power disclosed in the above- mentioned Korean Patent Application is a movable device, which is configured to convert heat to electric power and includes a mechanical frame having two vertical plates, and a horizontal boiler mounted on one of the two vertical plates such that one end of the boiler is held on a surface of the vertical plate. A horizontal condenser is mounted on the vertical plate at a position above the horizontal boiler such that one end of the horizontal condenser is held on the same surface of the vertical plate. The above-mentioned power generation device also has a divariant expansion unit, which has a rotary-type restricting vane and is mounted on the same surface of the vertical plate, with an output shaft included in the expansion unit and extending horizontally relative to the surface of the vertical plate. In the operation of the power generation device, refrigerant flows through the refrigerant circuit of a Rankine cycle, in which pressurized gas refrigerant flows from the boiler to the condenser while it expands in the expansion unit. The expansion unit acts as a means for pumping the refrigerant so as to actively circulate the refrigerant in the boiler. To accomplish the above- mentioned function of the expansion unit, the ends of both the boiler and the condenser are connected to the expansion unit, so that the gas refrigerant is condensed in the condenser to become a liquid refrigerant, and the liquid refrigerant is naturally recovered from the condenser into the boiler due to gravity. An electric power generator is installed on the mechanical frame at a position around the vertical plate. The above-mentioned power generation device also includes a hot fluid heat exchanging circuit unit, which couples the horizontal boiler to a heat source including a heat exchanger related to the horizontal boiler, and a cold fluid heat exchanging circuit unit, which couples the condenser to a cold source which includes a heat exchanger corresponding to the condenser. The power generation device further includes a fluid circulation pump, which is mounted to the vertical plate and is coupled to the output shaft of the expansion unit. The power generation device also includes a flow control unit, which controls the flow rate of the gas refrigerant flowing from the horizontal boiler to the expansion unit such that both the fluid circulation pump and the drive shaft of the electric power generator can be operated at consistent speeds. The flow control unit controls the flow rate of the fluid that flows through the heat exchanging circuit units, and includes a belt drive unit held on the vertical plate coupled to the output shaft of the expansion unit.

[4] However, the conventional power generation device, which converts heat to power, uses only a single thermal medium (refrigerant) such that the thermal medium exchanges heat with another fluid in the horizontal boiler. In other words, the horizontal boiler is used as an external heat source in the power generation device, so that the device requires a user to use fossil fuels and results in environmental pollution. Disclosure of Invention Technical Problem

[5] Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a heat-absorption-type power generation system, in which a first thermal medium of an external circulation cycle absorbs external heat while it passes through a heat absorption unit, exchanges heat with a second thermal medium flowing in an internal circulation cycle while the first thermal medium flows in the direction opposite the flowing direction of the second thermal medium, and generates power when the first thermal medium, which has absorbed heat, expands in an expansion unit, so that the power generation system does not use fossil fuels, such as petroleum, coal, etc., or nuclear power, thus causing no environmental pollution, and which also improves energy efficiency due to an increase in the yield of its output power relative to input energy, does not include an explosion stroke, unlike a conventional internal combustion engine, thus reducing operational noise, and can be used as an air conditioner or a refrigerator having no external unit, or can be used as a water-cooled chiller. Technical Solution

[6] In order to achieve the above object, according to one aspect of the present invention, there is provided a heat-absorption-type power generation system, comprising: an external circulation cycle including an expansion unit for generating power, with a first thermal medium flowing in the external circulation cycle; an internal circulation cycle arranged inside the external circulation cycle, with a second thermal medium flowing in the internal circulation cycle in a direction opposite a flowing direction of the first thermal medium of the external circulation cycle; and a heat absorption unit to transfer heat of an external fluid to the first thermal medium of the external circulation cycle, wherein the first thermal medium of the external circulation cycle exchanges heat with the second thermal medium of the internal circulation cycle in both a first heat exchanging unit and a second heat exchanging unit.

[7] The first thermal medium of the external circulation cycle may have a boiling point higher than a boiling point of the second thermal medium of the internal circulation cycle and lower than a boiling point of the external fluid fed to the heat absorption unit.

[8] The heat-absorption-type power generation system may further comprise: a vapor feed pump provided in a line of the external circulation cycle at a predetermined position between the heat absorption unit and the first heat exchanging unit.

Advantageous Effects

[9] As is apparent from the above descriptions, the heat-absorption-type power generation system according to the present invention absorbs heat from external water or air and generates power from the heat, so that it does not use fossil fuels, such as petroleum, coal, etc., or nuclear power, thereby causing no environmental pollution. The power generation system also has improved energy efficiency due to an increase in the yield of its output power relative to input energy. Furthermore, the system does not include an explosion stroke, unlike a conventional internal combustion engine, so that the system has remarkably reduced operational noise. Furthermore, the system may be used as an air conditioner or a refrigerator having no external unit, or may be used as a water-cooled chiller. Brief Description of the Drawings

[10] FIG. 1 is a block diagram illustrating the construction of a heat-absorption-type power generation system according to a first embodiment of the present invention; and

[11] FIG. 2 is a block diagram illustrating the construction of a heat- absorption-type power generation system according to a second embodiment of the present invention. Best Mode for Carrying Out the Invention

[12] Hereafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

[13] As shown in FIG. 1, a heat-absorption-type power generation system according to a first embodiment of the present invention includes an external circulation cycle 10 having an expansion unit 11 for generating power. An internal circulation cycle 20 is arranged inside the external circulation cycle 10, with a second thermal medium flowing in the internal circulation cycle 20 such that the second thermal medium flows in the direction opposite the flowing direction of a first thermal medium of the external circulation cycle 10. The power generation system also includes a heat absorption unit H3, which transfers heat of an external fluid to the first thermal medium of the external circulation cycle 10. In both a first heat exchanging unit Hl and a second heat exchanging unit H2 of the power generation system, the first thermal medium of the external circulation cycle 10 exchanges heat with the second thermal medium of the internal circulation cycle 20.

[14] The first thermal medium of the external circulation cycle 10 is a medium having a boiling point higher than that of the second thermal medium of the internal circulation cycle 20 and lower than that of the external fluid fed to the heat absorption unit H3. For example, when isobutane, having a boiling point of -12°C, is used as the first thermal medium, R22, having a boiling point of -40.8⁰C, much lower than that of the isobutane, is preferably used as the second thermal medium.

[15] In the external circulation cycle 10, the liquid-phase first thermal medium flows into the heat absorption unit H3, in which the first thermal medium absorbs heat from an external fluid so as to become a gas-phase medium. The gas-phase first thermal medium passes through the first heat exchanging unit Hl and exchanges heat with the second thermal medium of the internal circulation cycle 20, thus becoming a superheated vapor-phase medium. The superheated vapor-phase first thermal medium flows to the expansion unit 11 by way of a throttle valve 15 and adiabatically expands in the expansion unit 11, thus actuating the output shaft (not shown) of the expansion unit 11 and generating power. Thereafter, in the second heat exchanging unit H2, the gas-phase first thermal medium exchanges heat with the second thermal medium of the internal circulation cycle 20, thus becoming a liquid-phase medium. The liquid-phase first thermal medium is pumped by a liquid pump 13 and is fed to the heat absorption unit H3.

[16] When the external circulation cycle 10, in which the first thermal medium circulates, is adapted to a power generation system, the expansion unit 11 is used as a turbine. However, when the external circulation cycle 10 is adapted to another system having a function other than power generation, the expansion unit 11 may be configured as a rotary expansion unit, a divariant expansion unit, or a reciprocating expansion unit.

[17] In the internal circulation cycle 20, the superheated vapor-phase second thermal medium, which has been highly pressurized and heated to a high temperature in a compressor 21, is fed from the compressor 21 to the first heat exchanging unit Hl. In the first heat exchanging unit Hl, the superheated vapor-phase second thermal medium exchanges heat with the first thermal medium of the external circulation cycle 10 such that the first thermal medium absorbs heat from the second thermal medium. Thus, the second thermal medium in the first heat exchanging unit Hl is condensed and is fed to an expansion valve 23. The condensed second thermal medium adiabatically expands in the expansion valve 23, thus becoming a low temperature thermal medium. In the second heat exchanging unit H2, the low temperature second thermal medium exchanges heat with the first thermal medium of the external circulation cycle 10 such that the second thermal medium absorbs heat from the first thermal medium, thus becoming a vapor-phase thermal medium. Thereafter, the vapor-phase second thermal medium is fed to the compressor 21, thus accomplishing a cycle.

[18] As described above, the function of the internal circulation cycle 20 is equal to that of a heat pump system, in which the second heat exchanging unit H2 is used as a condenser.

[19] In the heat absorption unit H3, the external fluid may be air or water. Furthermore, the boiling point of the external fluid in the heat absorption unit H3 must be not lower than that of the first thermal medium.

[20] The heat-absorption-type power generation system having the above-mentioned construction according to the present invention is operated as follows. The power generation system generates power in the expansion unit 11 using the first thermal medium of the external circulation cycle 10, so that the operation of the system will be described based on the circulation of the first thermal medium. In the operation of the power generation system, a liquid-phase first thermal medium absorbs heat from an external fluid in the heat absorption unit H3, thus becoming a gas-phase medium. Assuming that the first thermal medium is isobutane, having a boiling point of -12°C, that the isobutane as the first thermal medium has reached the heat absorption unit H3 at an inlet temperature of -15°C, and that an external fluid of at a temperature of 20⁰C flows through the heat absorption unit H3 in the direction opposite the flowing direction of the first thermal medium so as to exchange heat with the first thermal medium, the isobutane used as the first thermal medium may be discharged from the heat absorption unit H3 in a gaseous state at a temperature of 15°C or higher .

[21] Thereafter, the first thermal medium exchanges heat with the second thermal medium of the internal circulation cycle 20 in the first heat exchanging unit Hl, thus becoming a superheated vapor-phase medium. In other words, due to a heat exchange process executed in the first heat exchanging unit Hl, in which the second thermal medium, having been adiabatically compressed by the compressor 21 and having a temperature of 80⁰C, exchanges heat with the second thermal medium, the first thermal medium becomes a superheated vapor-phase medium having a temperature of 70⁰C or higher. The superheated vapor-phase first thermal medium flows into the expansion unit 11 and actuates the output shaft of the expansion unit 11, thus generating power.

[22] If the coefficient of performance (COP) of the heat-absorption-type power generation system according to the present invention is set to 5, the power generation system can yield output power, which is equal to the maximum of 4.4 times the input power of the system, such as power for the motor of the compressor 21, the motor of the external fluid circulation pump, the fan motor 31, and the motor of the liquid pump 13. The power generation system of the present invention generates power by absorbing heat from external water or air, so that the system does not require the use fossil fuels, such as petroleum, coal, etc., or nuclear power, thus causing no environmental pollution.

[23] As shown in FIG. 2, the heat-absorption-type power generation system according to the second embodiment of the present invention further includes a vapor feed pump 15, which is provided in the line of the external circulation cycle 10 at a predetermined position between the heat absorption unit H3 and the first heat exchanging unit Hl. The general shape of the power generation system according to the second embodiment, except for the vapor feed pump 15, remains the same as that of the power generation system according to the first embodiment.

[24] The vapor feed pump 15 can clearly define the heat absorption unit H3 as an evaporation unit and the first heat exchanging unit Hl as a superheating unit. Thus, the vapor feed pump 15 can be used to prevent the liquid-phase first thermal medium from flowing into the first heat exchanging unit Hl. Industrial Applicability

[25] As is apparent from the above description, the heat-absorption-type power generation system according to the present invention absorbs heat from external water or air and generates power from the heat, so that it does not use fossil fuels, such as petroleum, coal, etc., or nuclear power, thereby causing no environmental pollution. The power generation system also has improved energy efficiency due to an increase in the yield of its output power relative to input energy, and does not include an explosion stroke, unlike a conventional internal combustion engine, so that the system has remarkably reduced operational noise. Another advantage of the system resides in that it may be used as an air conditioner or a refrigerator having no external unit, or may be used as a water-cooled chiller.

[26] Although preferred embodiments of the present invention have been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claim.

Claims

[1] A heat-absorption-type power generation system, comprising: an external circulation cycle including an expansion unit for generating power, with a first thermal medium flowing in the external circulation cycle; an internal circulation cycle arranged inside the external circulation cycle, with a second thermal medium flowing in the internal circulation cycle in a direction opposite a flowing direction of the first thermal medium of the external circulation cycle; and a heat absorption unit to transfer heat of an external fluid to the first thermal medium of the external circulation cycle, wherein the first thermal medium of the external circulation cycle exchanges heat with the second thermal medium of the internal circulation cycle in both a first heat exchanging unit and a second heat exchanging unit.

[2] The heat-absorption-type power generation system according to claim 1, wherein the first thermal medium of the external circulation cycle has a boiling point higher than a boiling point of the second thermal medium of the internal circulation cycle and lower than a boiling point of the external fluid fed to the heat absorption unit.

[3] The heat-absorption-type power generation system according to claim 1, wherein, in the external circulation cycle, the first thermal medium in a liquid phase flows into the heat absorption unit, in which the first thermal medium absorbs heat from the external fluid and becomes a gas-phase medium; the gas- phase first thermal medium passes through the first heat exchanging unit and exchanges heat with the second thermal medium of the internal circulation cycle, thus becoming a superheated vapor-phase medium; the superheated vapor-phase first thermal medium flows to the expansion unit by way of a throttle valve and adiabatically expands in the expansion unit, thus actuating an output shaft of the expansion unit and generating power; the gas-phase first thermal medium exchanges heat with the second thermal medium of the internal circulation cycle in the second heat exchanging unit, thus becoming a liquid-phase medium; and the liquid-phase first thermal medium is pumped by a liquid pump and is fed to the heat absorption unit.

[4] The heat-absorption-type power generation system according to claim 1, wherein, in the internal circulation cycle, the second thermal medium, which has been highly pressurized and heated to a high temperature in a compressor so as to become a superheated vapor-phase medium, is fed from the compressor to the first heat exchanging unit; the superheated vapor-phase second thermal medium exchanges heat with the first thermal medium of the external circulation cycle in the first heat exchanging unit such that the first thermal medium absorbs heat from the second thermal medium and the second thermal medium is condensed and is fed to an expansion valve; the condensed second thermal medium adia- batically expands in the expansion valve, thus becoming a low temperature thermal medium; the low temperature second thermal medium flows to the second heat exchanging unit and exchanges heat with the first thermal medium of the external circulation cycle in the second heat exchanging unit such that the second thermal medium absorbs heat from the first thermal medium, thus becoming a vapor-phase thermal medium; and the vapor-phase second thermal medium flows to the compressor.

[5] The heat-absorption-type power generation system according to claim 1, further comprising: a vapor feed pump provided in a line of the external circulation cycle at a predetermined position between the heat absorption unit and the first heat exchanging unit.