Note: Descriptions are shown in the official language in which they were submitted.
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THERMAL COMPRESSOR
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of and priority to Greece
Patent Application No.
20130100487, filed on August 30, 2013, the disclosure of which is herein
incorporated by
reference as if set forth in its entirety.
TECHNICAL FIELD
[0002] In general, various embodiments of this invention relate to the
compression of fluid
using thermal energy and, specifically, to a compressor having at least two
sealed containers
arranged in series that are periodically isolated to energize/heat a working
fluid contained
therein, such that the working fluid is propelled between the containers and
through the
compressor by natural circulation.
BACKGROUND
[0003] Compressors are commonly used mechanical devices, and are widely
used for fluid
compression and/or fluid circulation in hydraulic networks. Many prior art
compressors are
rotary compressors that include blades that rotate around a shaft and transfer
mechanical energy
to a working fluid, thereby increasing a fluid's potential energy. Such blades
are typically
enclosed in a hull or operate in direct contact with the environment. In
addition to rotary
compressors, reciprocating compressors are also used in industrial
applications, in which the
potential energy of a moving piston is utilized in order to compress the
working fluid inside a
cylinder. In both types of compressors, when the desired compression level is
attained, an
exhaust valve can open and release the compressed working fluid.
[0004] Conventional compressors such as these present a series of
disadvantages. One
such disadvantage is the inability to utilize thermal energy directly for the
compression of a
working fluid (i.e., without the prior transformation of the thermal energy to
mechanical
energy). This limitation precludes the use of such devices in applications
where the
transformation of the available thermal energy to mechanical energy is not
possible, or it can
lead to a reduction of an installation's efficiency. Another disadvantage of
conventional blade
compressors is their high cost and complexity of construction, as they are
specifically designed
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according to the thermodynamic specifications of a particular fluid. Further,
conventional
compressing devices can exhibit convulsions, or even total stall, during their
operation in cases
where the compressing fluid enters a two-phase flow zone. Consequently,
conventional
compressors are not considered suitable to compress a working fluid during a
two-phase flow.
[0005] Accordingly, there exists a need for an improved compressor that
improves upon the
disadvantages exhibited by conventional compressors, and particularly a
compressor that
reduces moving parts and can handle fluids in multiple phases.
SUMMARY OF THE INVENTION
[0006] The current invention is related to a compressor that can directly
transform thermal
energy into potential energy of a working fluid. Moreover, the compressor is
compatible with
typical installations that would otherwise include a standard compressor, as
well as installations
where an abundance of thermal energy and a need for compressing a working
fluid coexist.
[0007] In some embodiments, a compressor includes at least two sealed
heating containers
of independent size, shape and material, connected in series in which
compression takes place
successively with the use of thermal energy provided to the working fluid. In
some instances,
the heating containers are connected by a piping system and are periodically
isolated or
connected to one another by valves (e.g., solenoid valves). In general, the
valves included in
the compressor can include any type of appropriate valve which can be
controlled using any
known method. In some instances, the valves can be controlled by a central
controlling
system/controller. Through the periodic isolation/connection of the heating
containers the
working fluid can be propelled from an entering point to an exit point of the
thermal
compressor through natural circulation. In other embodiments, the heating
containers can be
compartments of a single pressure vessel, where the compartments to which
thermal energy is
provided are linked through a system of portable interfaces/diaphragms, thus
avoiding the need
for a piping system and valves. A portable interface/diaphragm can include a
slice of metal,
plastic, or other material adapted to move back and forth in order to allow or
prevent fluid flow.
These systems can be a part of a closed circuit or can operate autonomously
between any two
points of different pressure in the environment.
[0008] In some embodiments, in order to transfer thermal energy to the
working fluid, heat
exchangers, electrical heaters, or a combination of the two are utilized. Such
heat exchangers
or electrical heaters can be placed inside or outside of the containers, or
can be incorporated in
the walls of the containers. In instances in which heat exchangers are used,
the heat exchangers
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can receive thermal energy from a thermal circuit connected to the thermal
compressor. The
thermal circuit can receive thermal energy from, for example, the waste heat
of any installation
(e.g., a mechanical installation); the ambient heat of the environment; heat
that has been
harnessed from geothermal installations; the heat accumulated by solar thermal
collectors; a
steam generating apparatus; a turbo machine; a photovoltaic cell; an internal
combustion
engine; a nuclear reactor; a natural gas, diesel, gasoline, coal, biomass,
and/or ethanol burner; a
natural gas, diesel, gasoline, coal, biomass, and/or ethanol steam generator;
excess heat from
electrical coils; heat concentrated by mirrors; a concentration power plant
(e.g., a solar tower, a
linear concentration power plant, a Stirling dish, a linear Fresnel collector,
a Parabolic trough);
a Stirling engine; a steam engine; a Fracking natural gas fire; thermoelectric
materials; heat
generated from cooling machines (e.g., air conditioners, refrigerators, etc.);
and combinations
thereof The containers can be connected in a way that allows the simultaneous
and/or separate
heating of the containers through substantially simultaneous and/or separate
provision of heat.
The amount of heat provided to each container, as well as the duration of the
heating process,
are conducted in accordance with the timing of the entire system and can be
controlled by the
central controlling system.
[0009] The embodiments of the thermal compressor described herein exhibit
several
advantages over conventional compressors. First, by compressing the working
fluid within the
containers using thermal energy (e.g., through the use of heat exchangers),
the thermal
compressor can directly exploit thermal energy and convert it to potential
energy without
additional installations (e.g., those required for the transformation of
thermal to mechanical
energy) that incur significant energy losses, particularly in cases where
there is excess
exploitable thermal energy. Further, the absence of a fan and moving parts may
nullify
mechanical losses, as well as the need for scheduled maintenance, thus
increasing the
efficiency and reliability of the system. Moreover, due to the absence of a
fan and associated
moving parts, which are usually characterized by complex geometry, the
construction of the
thermal compressor can be significantly simpler and less expensive than
conventional
compressors.
[0010] In general, in one aspect, embodiments of the invention feature a
thermal
compressor that includes a first constant volume container having a first heat
exchanger
adapted to heat a working fluid; a second constant volume container
fluidically coupled in
series with the first constant volume container, the second constant volume
container including
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a second heat exchanger adapted to heat the working fluid; at least one
container connection
valve adapted to control flow of the working fluid between the first container
and the second
container; and a controller, where the first container and the second
container are arranged and
the controller controls the valve and heating of the working fluid to induce
natural circulation
from the first container to the second container due to at least one of a
difference in pressure, a
difference in working fluid density, and a difference in fluid level.
[0011] In various embodiments, at least one of the first heat exchanger
and the second heat
exchanger is adapted to use a thermal fluid, which in some cases can be
provided from a closed
thermal circuit, to heat the working fluid. The thermal circuit may receive
thermal energy from
at least one of a thermal solar collector, a turbo machine, a geothermal
installation, a steam
generating apparatus, a photovoltaic energy saving installation, the ambient
heat of the
environment, an internal combustion engine, a nuclear reactor, a burner,
electrical coils, heat
concentrated by mirrors, a concentration power plant, a Stirling engine, a
Fracking natural gas
fire, thermoelectric materials, and heat generated from cooling machines. In
some instances, at
least one of the first container and the second container include an
electrical resistor, which
may be disposed outside the container, insider the container, and/or in a well
of the container.
In certain instances, the controller is further adapted to isolate operation
of the first heat
exchanger and the second heat exchanger so that the first heat exchanger and
the second heat
exchanger heat the working fluid at different times. The controller may be
further adapted to
control at least one additional valve to selectively isolate the working fluid
in at least one of the
first container and the second container. In some instances, at least one of
the first heat
exchanger and the second heat exchanger is adapted to heat the working fluid
in an isochoric
process to increase pressure of the working fluid contained in at least one of
the first container
and the second container. The working fluid may be selected from the group
consisting of
water, atmospheric air, refrigerants (e.g., R134a, R1234yf, R407c, R11, R12,
R13, R14, R21,
R22, R23, R32, R41, R113, R114, R115, R116, R123, R124, R125, R141b, R142b,
R143a,
R152a, and combinations thereof), Organic Rankine cycle fluids (e.g., R245fa,
R141b, R236fa,
R218, R227ea, R236ea, R245ca, R365mfc, RC318, and combinations thereof),
ammonia,
propane, carbon dioxide, and combinations thereof
[0012] In some instances, the first container is disposed at a first height
and the second
container is disposed at a second height, where the first height is greater
than the second height
to induce natural flow from the first heat exchanger to the second heat
exchanger. The first
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heat exchanger may be adapted to heat the working fluid until a first pressure
is reached, and
the second heat exchanger may be adapted to heat the working fluid until a
second pressure is
reached. In some cases, the working fluid in the first container and the
second container
consists of a gas and liquid before heating, and after heating, the working
fluid in the first
container consists of a gas and liquid and the working fluid in the second
container consists of a
gas. The thermal compressor may include a second container connection valve,
and in some
instances liquid may flow from the first container to the second container and
gas may flow
from the second container to the first container when the container connection
valves are
opened. In some cases, the first container is adapted to hold the working
fluid at a first density
and the second container is adapted to hold the working fluid at a second
density when the
container connection valve is closed to induce natural flow between the first
container and the
second container when the container connection valve is opened.
[0013] The thermal compressor may be adapted to be coupled to a work
producing system,
which may include an expanding device, a generator, and a work system heat
exchanger, where
the working fluid travels through the work producing system. In some
instances, the work
producing system is configured to provide, through natural circulation, a mass
transfer of the
working fluid from the work producing system to the first container after the
working fluid
exits the work system heat exchanger. In such instances, the work producing
system may
further include at least one buffer tank disposed between the first container
and the work
system heat exchanger. In some instances, the work producing system is
configured to provide,
through natural circulation, a mass transfer of the working fluid from the
second container to
the work producing system before the working fluid enters the expanding
device. In such
instances, the work producing system may further include at least one buffer
tank disposed
between the second container and the expanding device. In some instances, the
container
connector valve includes a portable interface to selectively obstruct flow. In
certain
embodiments, the thermal compressor can include at least one additional
container arranged in
series with the first container and the second container. In some cases, the
thermal compressor
is adapted to be coupled to a heat pump, which can include a compressor, a
condenser, an
expansion element, and an evaporator.
[0014] In general, in another aspect, embodiments of the invention feature
a method of
thermally compressing a working fluid. The method may include the steps of
heating a
working fluid in a first constant volume container with a first heat
exchanger, heating the
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working fluid in a second constant volume container with a second heat
exchanger, and
controlling at least one container connection valve disposed between the first
container and the
second container to allow natural circulation of the working fluid from the
first container to the
second container based on at least one of a difference in pressure, a
difference in working fluid
density, and a difference in fluid level.
[0015] In various embodiments, the working fluid may be heated in an
isochoric process.
In some instances, the first heat exchanger heats the working fluid when
pressure in the first
container is below a threshold value. In such instances, the second container
may transfer the
working fluid to a working circuit during heating of the working fluid by the
first heat
exchanger, and a thermal circuit may circulate a thermal fluid through the
first heat exchanger
to heat the working fluid. In other instances, the second heat exchanger heats
the working fluid
when pressure in the second container is below a threshold value. In such
instances, the first
container may receive the working fluid from a working circuit during heating
of the working
fluid by the second heat exchanger, and a thermal circuit may circulate
thermal fluid through
the second heat exchanger to heat the working fluid. In some cases, the second
heat exchanger
heats the working fluid before the first heat exchanger heats the working
fluid within a cycle.
The valve may be opened after the first heat exchanger and the second heat
exchanger have
heated the working liquid. In certain embodiments, a density in the first
container is greater
than a density in the second container to promote natural circulation.
BRIEF DESCRIPTION OF THE FIGURES
[0016] In the drawings, like reference characters generally refer to the
same parts
throughout the different views. Also, the drawings are not necessarily to
scale, emphasis
instead generally being placed upon illustrating the principles of the
invention. In the
following description, various embodiments of the present invention are
described with
reference to the following drawings.
FIG. 1 is a schematic fluid circuit diagram of a thermal compressor connected
to a
thermal circuit and a work producing system that generates electricity,
according to one
embodiment.
FIGS. 2A, 2B are a schematic semi-transparent side view and non-transparent
perspective view, respectively, of a container including an electrical
resistor within its interior
according to one embodiment.
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FIGS. 3A, 3B are a schematic semi-transparent side view and non-transparent
side
view, respectively, of a container having an electrical resistor wreathed
about its exterior,
according to one embodiment.
FIG. 4 is a schematic, semi-transparent side view of an exemplary
configuration of
the thermal compressor during heating of working fluid in a container,
according to one
embodiment.
FIG. 5 is a schematic, semi-transparent side view of an exemplary
configuration of
the thermal compressor during mass transfer of working fluid into and out of
the thermal
compressor, according to one embodiment.
FIG. 6 is a schematic, semi-transparent side view of an exemplary
configuration of
the thermal compressor during heating of working fluid in another container,
according to one
embodiment.
FIG. 7 is a schematic, semi-transparent side view of an exemplary
configuration of
the thermal compressor during mass transfer of working fluid between two
containers through
natural circulation, according to one embodiment.
FIG. 8 is a table showing the states of the working fluid contained within the
containers at various phases of a thermal compression cycle, according to one
embodiment.
FIGS. 9A-9C are tables with exemplary operating parameters for a turbine in a
work
producing system for use with the thermal compressor system shown in FIG. 1,
according to
one embodiment.
FIG. 10 is a schematic, fluid circuit diagram of a thermal compressor,
according to
one embodiment.
FIG. 11 is a schematic, fluid circuit diagram of a thermal compressor,
according to
another embodiment.
FIG. 12 is a schematic, fluid circuit diagram of a thermal compressor having
three
containers, according to one embodiment.
FIG. 13 is a schematic, fluid circuit diagram of two thermal compressors in
parallel
connected to a thermal circuit, according to one embodiment.
DETAILED DESCRIPTION
[0017] Embodiments of the present invention are directed to a compressor
that compresses
a working fluid with direct use of thermal energy (e.g., from the environment
or as the waste
from an installation, amongst other heat sources). In general, the compressor
of the present
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invention can be used in conjunction with any working fluid, for example,
water, atmospheric
air, refrigerants (e.g., R134a, R1234yf, R407c, R11, R12, R13, R21, R22, R23,
R32, R41,
R113, R114, R115, R116, R123, R124, R125, R141b, R142b, R143a, R152a), Organic
Rankine
cycle fluids (e.g., R245fa, R141b, R236fa, R218, R227ea, R236ea, R245ca,
R365mfc, RC318),
ammonia, propane, carbon dioxide, and combinations thereof Certain embodiments
of the
compressor are described in greater detail below in conjunction with the
accompanying
drawings.
[0018] In
a first embodiment, depicted in FIG. 1, a thermal work system 137 includes a
thermal compressor 16 connected to a thermal circuit 135 that provides heat to
the thermal
compressor 16 and a work producing system 136. FIG. 1 depicts an embodiment of
the thermal
circuit 135 with a thermal energy input 1 (e.g., a solar thermal collector). A
solar thermal
collector can be used to exploit the excess heat accumulated on such
collectors by converting
the solar thermal collector 1 into a cogeneration unit that produces
electricity in addition to hot
water. The electricity generated can be directly utilized for domestic
consumption, and can
therefore reduce a household's electricity consumption from the grid. The
thermal energy input
1 can receive thermal energy from any known thermal energy source (e.g., the
waste heat of
any installation, the ambient heat of the environment, heat that has been
harnessed from
geothermal installations, etc.). Further, while FIG. 1 depicts use of
compressed fluid from the
thermal compressor 16 with the work producing system 136 to generate
electricity, in general,
the thermal compressor 16 can be used in conjunction with any system that uses
compressed
fluid. For example, the thermal compressor 16 can be used in conjunction with
a heat pump.
[0019] In
various embodiments, the thermal compressor 16 includes a first container 5
and
a second container 6. The containers 5, 6 may each have a constant volume. In
some
embodiments, the first container 5 may have a smaller volume than the second
container 6.
Fluid (e.g., a working fluid) within the containers 5, 6 can be heated using
heating elements
133, 134, that include, for example, heat exchangers, electrical heaters,
electrical resistors, or
combinations thereof In embodiments in which electrical resistors are used, in
some instances
the electrical resistors can be located within the interior of the heat
containers 5, 6, as depicted,
for example, in FIGS. 2A and 2B. In other instances, the electrical resistors
can be wreathed
around the exterior of the heat containers 5, 6, as depicted for example in
FIGS. 3A and 3B.
The containers 5, 6 may include pressure sensors 206, 208, respectively, to
sense pressure of
the working fluid therein. The containers 5, 6 may include pressure safety
valves 205, 207,
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respectively, to protect the containers 5, 6 from excessive pressures. In some
embodiments, the
container 5 is connected to the container 6 by a pipe 132 including a
container connection valve
109 (e.g., a solenoid valve). In other embodiments, as shown for example in
FIGS. 4-7, the
containers 5, 6 are connected using a double pipe and valve system having, for
example, an
upper pipe 132a including an upper container connection valve 109a and a lower
pipe 132b
including a lower container connection valve 109b. In other embodiments, the
containers 5, 6
may be compartments of a single pressure vessel and connected through a system
of portable
interfaces/diaphragms. The connection(s) between the containers 5, 6 can also
be controlled by
poppet valves, moving interfaces, or any other device capable of controlling
flow through a
pipe (or pipes) placed between the containers 5, 6. The container 5 can
receive working fluid
requiring compression from the work producing system 136, such as working
fluid exiting an
expanding device 10 (described in greater detail below). The flow of working
fluid into the
container 5 can be controlled by a valve 115. The container 6 can deliver a
compressed
working fluid to the work producing system 136. The flow of compressed working
fluid can be
controlled by a valve 110. The operation of any valves in the thermal circuit
135, the thermal
compressor 16, and the work producing system 136, or a subset thereof, can be
controlled by a
central controlling system (or controller) 116, for example, in response to
measurements
observed by various pressure and temperature sensors throughout the thermal
work system 137
to achieve a desired thermodynamic state within the thermal work system 137.
[0020] In various embodiments, the containers 5, 6 can be isolated from
each other (e.g., by
closing the valve 109), allowing a different amount of thermal energy to be
provided to the
container 5 than is provided to the container 6. By enabling isolation of the
containers 5, 6
from each other, the pressure and/or density of the working fluid contained
within the container
5 can be controlled to be greater than the pressure and/or density of the
working fluid contained
within the container 6 at select times during the cycle. Further, in some
embodiments, the
container 5 can be installed at a higher altitude ("level") than the container
6. Following the
isolation and separate provision of thermal energy to the containers 5, 6, the
containers 5, 6 can
be connected to one another (e.g., using either a single pipe or a double pipe
arrangement), at
which point the pressure, density, and/or level difference between the
containers induces flow
of the working fluid from the container 5 to the container 6. This flow of
fluid created by such
pressure, density, and/or level differences (and characterized by generally
few or a total
absence of moving mechanical parts driving the working fluid) is referred to
as "natural
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circulation." A description of one embodiment of the system 137 operating
according to these
principles is described below in reference to FIG. 1.
[0021] As shown in the embodiment depicted in FIG. 1, the thermal
compressor 16 is
connected to the work producing system 136. In the embodiment shown, the work
producing
system 136 includes a buffer tank 7, which can contain or be wreathed in an
electrical resistor 8
to which voltage is provided by, for example, a battery 9 or a portion of the
electricity
generated by the work producing system 136. The buffer tank 7 may be equipped
with a
pressure transmitter 209, a thermometer (or temperature sensor) 211, and a
pressure safety
valve 210. A valve 111 and a flow regulating valve 212 can be placed between
the buffer tank
7 and the turbine 10. The turbine 10 (or other expansion device) can be
connected to an
electrical generator 11, which converts the mechanical energy of the turbine
10 into electricity.
In some embodiments, the electrical generator 11 and the turbine 10 are
equipped with
electronic sensors 213 and/or controllers 214, which provide information
regarding the status of
their operation. The working fluid exiting the turbine 10 may enter a
condenser (or work
system heat exchanger) 12 (in some instances via a valve 112). The condenser
12 can have a
pressure meter 215 and/or a thermometer 216 installed at its outlet in order
to, for example,
monitor and/or regulate the operation of the work producing system 136.
Following the
condenser 12, the working fluid may flow through a check valve 113 and a valve
114 before
entering a buffer/suction tank 13. The buffer tank 13 can potentially contain
or be wreathed in
an electrical resistor 14, to which voltage is provided by, for example, a
battery 15 or a portion
of the electricity generated by the work producing system 136. The buffer tank
15 may be
equipped with a pressure transmitter 218 and a pressure safety valve 217. In
some
embodiments, the inlet of the thermal compressor 16 is connected to the buffer
tank 13 via the
valve 115. In embodiments in which the thermal compressor 16 is coupled to a
heat pump, the
heat pump can include a similar system as the work producing system 136
described above, but
with an evaporator 140 and fluid flowing in the opposite direction.
[0022] As shown in FIG. 1, the thermal compressor 16 may receive thermal
energy from
the thermal circuit 135 that includes a thermal energy input (e.g., a solar
thermal collector) 1
that collects, delivers, and/or heats a thermal fluid (e.g., water/antifreeze
solution) using solar
energy. Although this disclosure refers to solar heated water/antifreeze
solution, other thermal
fluids can be used as well, such as water, atmospheric air, refrigerants
(e.g., R134a, R1234yf,
R407c, R11, R12, R13, R21, R22, R23, R32, R41, R113, R114, R115, R116, R123,
R124,
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R125, R141b, R142b, R143a, R152a), Organic Rankine cycle fluids (e.g., R245fa,
R141b,
R236fa, R218, R227ea, R236ea, R245ca, R365mfc, RC318), ammonia, propane,
carbon
dioxide, and combinations thereof In some instances, the thermal circuit 135
delivers heated
thermal fluid from the thermal solar collector 1 to a storage/heater tank 3,
in some cases
transporting the thermal fluid through the valves 102 and 104 to a heat
exchanger contained in
the storage/heater tank 3, in order for the fluid in the storage/heater tank 3
to be heated for
domestic or other use. Heated thermal fluid can also be transported from the
heat exchanger
contained in the storage/heater tank 3 to an expansion tank 4, in some cases
through a valve
105. In addition to the expansion tank 4, the thermal circuit 135 can also
include a pressure
safety valve 203 to protect the system 137 from potentially destructive
pressure levels. In other
instances, the thermal circuit 135 delivers heated thermal fluid from solar
thermal collector 1 to
a heat exchanger 133 for heating working fluid in the container 5, and to heat
exchanger 134
for heating working fluid in the container 6 of the thermal compressor 16. In
some cases, the
heated thermal fluid can be delivered to the thermal compressor 16 by
transporting it through a
valve 101, a circulator 2, and a check valve 103.
[0023] In various embodiments, when the temperature of the thermal fluid
in the
storage/heater tank 3 (which can be monitored by a temperature sensor 202)
surpasses a
predetermined value, and/or the temperature of the thermal fluid flowing
through the thermal
circuit 135 (which can be monitored by a thermometer 201) surpasses a
predetermined value,
circulation of working fluid in the work producing system 136 is initiated,
allowing for
expansion of compressed working fluid to produce electricity.
[0024] In some embodiments, measurements from the pressure sensors 206,
208, 209, 215,
218 and the thermometers 211, 216 are gathered. Based on these measurements,
working fluid
in the buffer tanks 7, 13 can be isochorically heated (i.e., such that
temperature and pressure are
increased at a constant volume) using the electrical resistors 8, 14, or
another heat source, until
the pressure and/or density of the working fluid reaches a desired level. The
valves 110, 111,
112, 114, 115 may be controlled by the controller 116 to induce an initial
flow of working fluid
in the work producing system 136. Once the desired thermodynamic state of the
work
producing system 136 is attained (e.g., natural circulation is induced across
the turbine 10, to
the container 5, and/or from the container 6) the heating of working fluid in
the buffer tanks 7,
13 may cease. However, such heating may continue and/or resume if, for
example, the
thermodynamic state of the work producing system 136 deviates from its desired
state. As long
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as the turbine 10 and the electrical generator 11 do not emit a malfunction
signal, the valve 111
may remain open in order to allow the transfer of working fluid from the
buffer tank 7 to the
turbine 10. A flow adjustment valve 212 may adjust the amount of working fluid
provided to
the turbine 10 in order for the electrical generator 11 to operate at the
desired operating point.
The working fluid exiting the turbine 10 (e.g., in the form of superheated
steam) may enter the
condenser 12, and after being condensed into a liquid, be transported to and
accumulated in the
buffer tank 13. In some embodiments, the check valve 113 ensures that the flow
of the
working fluid is directed towards the buffer tank 13 and not permitted to
backflow.
[0025] In parallel with the above-described operation of the work
producing circuit 136, the
thermal circuit 135 can also be in operation. In some embodiments, as soon as
the pressure in
the container 6 is lower than a predetermined level, the valve 107 may be
opened, the valve 104
may be closed, and a valve 106a may be opened (while a valve 106b is closed)
to direct heated
thermal fluid in the thermal circuit 135 to a heat exchanger 134 coupled to
(e.g., contained
within) the container 6. In some embodiments, when closing the valve 102 and
opening the
valve 101, a circulator 2 is set into motion at a volumetric flow rate such
that an appropriate
amount of heat is transferred to the working fluid contained within the
container 6, thereby
isochorically heating the working fluid to a desired pressure and density.
Heating the working
fluid in the container 6 to such desired pressure may result in the fluid
being heated from a
liquid (or liquid/gas mixture) into a gas without any liquid. The volumetric
flow rate of the
thermal fluid and transfer of thermal energy to the working fluid can be based
on a variety of
measurements in the thermal circuit 135, including those taken by the
thermometers 201, 204.
The check valve 103 can be placed in a depression of the circulator 2 so as to
prevent the
working fluid from flowing backwards towards the circulator 2.
[0026] At the same time as working fluid in the container 6 is being
heated, the valve 115
may be open in order to allow the transfer of working fluid from the buffer
tank 13 to the
container 5. The working fluid transitions from Phase 3 to Phase 1, as
indicated in FIG. 8 and
described below. Such fluid transfer may occur by natural circulation and be
induced by a
pressure, density, and/or level difference between the working fluid contained
within the buffer
tank 13 and the container 5. As the working fluid being transferred from the
buffer tank 13 to
the container 5 has already passed through the condenser 12, it may be in a
liquid phase. FIG.
4 shows an example configuration of the thermal compressor 16 during this
process in an
embodiment in which the containers 5, 6 are connected by a double piping
system with the
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pipes 132a, 132b and the valves 109a, 109b. In this embodiment, the valves
109a, 109b, 110
are closed in order to isolate working fluid within the container 6 as the
working fluid is heated
to a gas. In some embodiments, as shown for example in FIG. 5, if the working
fluid contained
in the container 6 reaches its desired pressure and/or density before the mass
transfer between
the buffer tank 13 and the container 5 is complete, the valve 110 may open and
the working
fluid in a gas phase in the container 6 may flow to the buffer tank 7 while
the working fluid in
the liquid phase is still entering the container 5. The working fluid may flow
naturally from the
container 6 to the buffer tank 7 due to higher pressure in the container 6
than the buffer tank 7.
[0027] Once the pressure of the working fluid within the container 6
reaches a desirable
level, the valve 107 can be closed to cease heating the working fluid in the
container 6. At the
same time, the container 5 may be isolated and heating of the working fluid
contained therein
may begin. This process transitions the working fluid from Phase 1 to Phase 2,
as described in
FIG. 8 (described below). For example, the valves 106b, 108 may be opened and
the valve
106a closed to direct the thermal fluid a heat exchanger 133 coupled to (e.g.,
contained within)
the container 5. FIG. 6 shows an example configuration of the thermal
compressor 16 during
this process. In this embodiment, the valves 109a, 109b, and 115 are closed
while the working
fluid (e.g., in liquid or liquid/gas form) contained in the container 5 is
heated. The amount of
thermal energy delivered to the container 5 may be controlled by adjusting the
volumetric flow
rate of the circulator 2 (which can take into account the temperature readings
of the
thermometers 201, 204) such that the working fluid contained within the
container 5 is
isochorically heated to a desired state (e.g., a greater pressure and/or
greater density than the
working fluid in the container 6). Heating the working fluid in the container
5 to such desired
pressure may result in the working fluid transitioning from a liquid into a
liquid/gas mixture.
As shown in FIG. 6, while the working fluid within the container 5 is being
heated, the valve
110 may be open in order to allow mass transfer of working fluid from the
container 6 to the
buffer tank 7. Such working fluid mass transfer may occur by natural
circulation, as can be
induced by a pressure, density, and/or level difference between the working
fluid contained
within the container 6 and the working fluid in the buffer tank 7. Once a
desired amount of
working fluid has been transferred from the container 6 to the buffer tank 7,
the valve 110 may
be closed to isolate the container 6 from the buffer tank 7.
[0028] When the pressure and density of the working fluid within the
container 5 reaches a
desired level, the valves 101, 106b, 108 may close, isolating the containers
5, 6 from the
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thermal circuit 135. In some embodiments, when the containers 5, 6 are
isolated, the valves
102, 104, 105 are opened and heated thermal fluid exiting the solar thermal
collector 1 is
directed into the heat exchanger contained in the storage/heater tank 3. In
addition, the valves
110, 115 may be closed and the containers 5, 6 may be isolated from the work
producing
system 136, as well. Following the isolation of the containers 5, 6 from the
thermal circuit 135
and the work producing system 136, the containers 5, 6 can be fluidically
connected to each
other to allow for the flow of working fluid from the container 5 to the
container 6 by natural
circulation (i.e., induced by a pressure, density, and/or level difference
between working fluid
in the containers 5, 6). This process causes the working fluid to transition
from Phase 2 to
Phase 3, as identified in FIG. 8. In an embodiment in which the container 5 is
connected to the
container 6 by a single pipe 132, such connection can occur by opening the
valve 109. In an
embodiment in which the container 5 is connected to the container 6 by a
double pipe system,
as depicted in FIG. 7, such connection can occur by opening the valves 109a,
109b, leading to
natural circulation of working fluid between the containers 5, 6. In such an
embodiment, after
heating of working fluid in the container 5 when the container 5 contains a
liquid/gas mixture
and the container 6 contains a gas (Phase 2 in FIG. 8), movement of working
fluid between the
containers 5, 6 can occur with few or no mechanical parts driving the flow of
working fluid.
Liquid of the liquid/gas mixture is located in the lower portion of the
container 5 and the gas is
located in the upper portion of the container 5 based on differences in
density. In this
embodiment, the density of the working fluid contained in the container 5 may
be greater than
the density of the working fluid contained in the container 6 (e.g., the
density of the liquid/gas
mixture in the container 5 is greater than the density of the gas in the
container 6). The density
differences can induce flow of the liquid working fluid from the container 5
through the pipe
132b (which connects the lower portion of the container 5 to the lower portion
of the container
6) into the container 6. Because the container 6 is of fixed volume and the
valve 110 is closed,
the flow of liquid into the container 6 may force some of the working fluid in
gaseous form
from the container 6 to the container 5 through the pipe 132a (which connects
an upper portion
of heating container 6 to an upper portion of heating container 5). The
induced flow between
the containers 5, 6 can continue until the pressure within the two heating
containers becomes
equal (e.g., until the pressure sensors 206, 208 emit the same signal), which
in some cases can
take several seconds, at which time the valve 109 (or the valves 109a, 109b)
may be closed.
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[0029] At this point, the disclosure has described an exemplary complete
cycle of the
operation of the thermal compressor 16 of the present invention when used in
conjunction with
the thermal circuit 135 and the work producing system 136, as shown in FIG. 1.
Subsequently,
the cycle may be repeated, starting with the isolation and heating of working
fluid contained
within the container 6, and transitioning the working fluid from Phase 3 to
Phase 1, as
identified in FIG. 8.
[0030] In some embodiments, in a situation in which any sensor or central
controlling
system 116 emits a malfunction and/or error signal, the system 137 described
above may cease
its function. In such situations, once functionality is restored, the entire
process described
above, starting with generating an initial flow in the work producing system
136 (e.g., by
isochorically heating working fluid in the buffer tanks 7, 13), can be
repeated.
[0031] The work producing system 136 can operate effectively when paired
with the
thermal compressor 16. FIGS. 9A-9C include exemplary operating parameters for
the system
136 at the turbine 10.
[0032] As described above, the thermal compressor 16 can receive thermal
energy from a
wide variety of thermal energy sources, including from the waste heat of any
installation (e.g.,
a mechanical installation); the ambient heat of the environment; heat that has
been harnessed
from geothermal installations; the heat accumulated by solar thermal
collectors; a steam
generating apparatus; a turbo machine; a photovoltaic cell; an internal
combustion engine; a
nuclear reactor; a natural gas, diesel, gasoline, coal, biomass, and/or
ethanol burner; a natural
gas, diesel, gasoline, coal, biomass, and/or ethanol steam generator; excess
heat from electrical
coils; heat concentrated by mirrors; a concentration power plant (e.g., a
solar tower, a linear
concentration power plant, a Stirling dish, a linear Fresnel collector, a
Parabolic trough); a
Stirling engine; a steam engine; a Fracking natural gas fire; thermoelectric
materials; and heat
generated from cooling machines (e.g., air conditioners, refrigerators, etc.).
Further, the
working fluid compressed by the thermal compressor 16 can be used in a wide
variety of
applications, including the compression of air and/or other fluids, solar
and/or conventional
cooling applications, desalination applications, refrigeration, Stirling
engine applications,
thermoelectric applications, internal combustion engine applications, turbo
machinery
applications, large scale steam turbine applications, power production
applications, automobile
driving power applications, and combinations thereof This flexibility is an
asset, and FIGS.
10, 11, and 12 depict examples of thermal compressors 16 in isolation that can
be installed in
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many installations requiring a compressor, including those that also have a
source of thermal
energy.
[0033] In various embodiments, the valves 106a, 106b (e.g., solenoid
valves) may be
replaced by a single three-way valve 106, as shown, for example, in FIG. 10.
In such
embodiments, in situations in which heated thermal fluid is delivered to the
container 6, the
valve 106 can direct thermal fluid to the container 6 while precluding flow to
the container 5.
The opposite applies when thermal fluid is to be delivered to the container 5.
[0034] In various embodiments, the thermal compressor 16 can include
three (or more)
heating containers 5, 6, 20, as shown, for example, in FIG. 12. Although FIG.
12 shows a
system including three heating containers, the same principles can be applied
to add as many
heating containers to the thermal compressor 16 as desired. In some instances,
the pressure,
density, and/or level difference(s) between the container 5 and the container
6 may not generate
desirable thermodynamic and/or flow conditions. To improve performance, one
option is to
add the third heating container 20 to the thermal compressor 16. Similar to
the containers 5, 6,
the container 20 may include a pressure sensor 220 and a pressure safety valve
221. The
addition of more heating containers can allow the working fluid to reach its
desired state in
more than two stages. The container 20 can be isolated and separately heated
in the same
manner as described above regarding the isolation and separate heating of the
container 5 and
the container 6. The container 20 can be separately heated by, for example,
closing the valves
107, 108, opening the valve 130, and having the four-way valve 106 direct
heated thermal fluid
from the thermal circuit 135 to a heat exchanger 138 coupled to the container
20. The
container 20 can be isolated from the work producing system 136 and other
containers 5, 6 by,
for example, closing a valve 131 (or analogous valves in a double pipe
connection
embodiment) and the valve 110. The working fluid contained within the
container 20 can be
heated to a pressure and/or a density, and/or kept at an elevation, that
induces the flow of
working fluid from the container 6 to the container 20 by natural circulation.
The working
fluid can be induced to flow from the container 5 to the container 6 in the
same manner as
described above with respect to FIG. 1. The addition of additional heating
containers can result
in less energy being required to achieve a desired pressure increase.
[0035] In various embodiments, the thermal compressors described above may
be used in
parallel (e.g., thermal compressors 16a, 16b in FIG. 13) to improve temporal
continuity and
attain a substantially constant volumetric flow rate at an outlet 139 of the
thermal compressors
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16a, 16b. Such operation can be useful in situations where the outlet 139 of
the thermal
compressors 16a, 16b is connected to a device that requires constant fluid
flow to operate (e.g.,
certain turbines or other expanders). As depicted in FIG. 13, the first
thermal compressor 16a
includes a container 5a and a container 6a, which is arranged in parallel to a
second thermal
compressor 16b including a container 5b and a container 6b. Although FIG. 13
only shows two
thermal compressors 16a, 16b in parallel, in other embodiments, more thermal
compressors can
be included.
[0036] Each numerical value presented herein, for example, in a table or
a chart, is
contemplated to represent an exemplary value in a range for a corresponding
parameter.
Accordingly, when added to the claims, the numerical value provides express
support for
claiming a range around that value, which may lie above or below the numerical
value, in
accordance with the teachings herein. Absent inclusion in the claims, each
numerical value
presented herein is not to be considered limiting in any regard.
[0037] The terms and expressions employed herein are used as terms and
expressions of
description and not of limitation, and there is no intention, in the use of
such terms and
expressions, of excluding any equivalents of the features shown and described
or portions
thereof In addition, having described certain embodiments of the invention, it
will be apparent
to those of ordinary skill in the art that other embodiments incorporating the
concepts disclosed
herein may be used without departing from the spirit and scope of the
invention. The structural
features and operational functions of the various embodiments may be arranged
in various
combinations and permutations, and all are considered to be within the scope
of the disclosed
invention. Accordingly, the described embodiments are to be considered in all
respects as only
illustrative and not restrictive. Furthermore, the configurations, materials,
and dimensions
described herein are intended as illustrative and in no way limiting.
Similarly, although
physical explanations have been provided for explanatory purposes, there is no
intent to be
bound by any particular theory or mechanism, or to limit the claims in
accordance therewith.
