Note: Descriptions are shown in the official language in which they were submitted.
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Description
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Closed ~eat Pump System Producing Electrical Power
Technical Field
This invention relates to a heat pump process and
apparatus which is applicable to the generation of elec-
trical power, production of mechanical power, and cooling of
discharges from nuclear and thermal electrical generating
.~ plants and more particularly to a process and apparatus
comprising an evaporator and a condenser where the heating
necessary to cause evaporation in the evaporator and the
cooling necessary to cause condensing in the condenser are
obtained from warm and cold fluid sources.
Background Art
The shortage of oil and natural gas is rapidly becoming
a significant problem for producers of electrical energy as
well as other processors that require large amounts of
energy to process their products. As the supplies of the
fossilized fuels are diminishing and their costs escalating,
it is necessary to investigate the so-called natural ener-
gies such as hydro power, solar energy, indirect solar
- energy, etc. One of the many faceted solutions to the
present energy crisis appears to lie in the utilization of
the energy differentials existing between two fluid sources
as different temperatures, such as are present in tropical
ocean waters wherein the warm ocean surface waters are at
temperatures considerably higher than the cold deep ocean
waters.
Although the total energy existing in two large fluid
sources at different temperatures is enormous, the specific
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energy, the energy existing per unit of weight or mass is
~, very small indeed, necessitating new and novel techniques
and cycles to utilize the small amount of specific energy
available to do productive work.
The heat pump has been known as one of the most efficient
methods for heating and cooling with the application of
small amounts of external energy. Application of heat pump
principles appear to offer the solutions for obtaining
usable energy from the aforementioned energy sources with
low specific energies. Previously, heat pump systems have
been designed to obtain the maximum amount of heat transfer
from one source to another source with the minimum amount of
power applied. To utilize heat sources of low specific
energy for the production of energy, it is now necessary to
devise heat pump systems that will produce the maximum
amount of energy with the minimum amount of heat energy
applied.
Therefore it is an object of this invention to provide
a process and an apparatus which overcomes the aforemen-
tioned inadequacies of the prior art devices and provides animprovement which is a significant contribution to the
advancement of the pertinent art.
Accordingly, it is an object of the present invention
to provide a novel and improved heat pump system which is
operable to produce mechanical power and/or electrical power
using a warm fluid source for supplying heat to offset the
heat loss which occurs during vaporization of a refrigerant
and a cold fluid source to effect condensing of the refriger-
ant vapors.
It is also an object of the present invention to
provide a process and an apparatus into which a prime mover
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is driven by the pressure difference between the evaporator
section of the apparatus and the lower saturation pressure
of the refrigerant in the condenser section of the apparatus.
It is another object of this invention to provide a
means of converting all or part of the output of the said
prime mover to electrical energy by means of an electrical
generator and an electrical control means.
It is still another object of the present invention to
provide a controlled means of returning the condensed
refrigerant from the condenser means to the evaporator means
to replace the refrigerant evaporated in the evaporator
means.
` A further object of the present invention is to provide
- a means of controlling the speed of the prime mover means
regardless of variations in the load on the generator means,
by means of a control valve means and conduit means in
parallel with the prime mover means which is capable of by-
passing a portion of the flow of refrigerant vapors from the
evaporator means to the condenser means, thereby controlling
the pressure across the prime mover means.
- Yet another object of the present invention is to
provide a heat exchanger means and a pump means to bring the
refrigerant in the evaporator means into thermal contact
with the warm fluid source, effectively replacing the heat
of vaporization lost in the evaporator means by the evapora-
ting of the refrigerant.
Still another object of the present invention is to
provide a heat exchanger means within the condenser means
wherein the refrigerant vapors in the condenser means are
brought into thermal contact with the cooling fluid to
remove the heat of condensation.
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/,nother object of the present invention is to provide a
closed system in which a refrigerant is present at satura-
tion pressures corresponding to the saturation pressures for
the given refrigerant at the various temperatures that are
present in the system.
Another object of the present invention is to provide a
prime mover of the positive displacement type with the
lowest possible volumetric efficiency in order to derive the
maximum power from the existing and available pressure
differentials while requiring the least mass flow of re-
frigerant vapors and subsequently requiring the least energy
from the fluid sources.
Other objects and a fuller understanding of this
invention may be had by referring to the summary of the
invention, the description and the claims, taken in con-
junction with the accompanying drawing.
Disclosure of the Invention
It has now been found that the foregoing and related
objects can readily be attained in a novel and improved heat
pump process and apparatus for the production of mechanical
power and electrical energy using fluid sources of low
specific energy as the means of powering the process and
apparatus. Although these two fluid sources could be oil,
natural gas, atmospheric air, waste streams, salt water,
fresh water, or any other two fluids in which energy differ-
entials exist as a function of their different temperatures;
I shall, for simplicity, refer to the two fluids as a warm
water source and a cold water source.
This process and apparatus comprises a closed heat pump
system containing a refrigerant such as ammonia, freon,
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water, carbon dioxide, carrene, or any other suitable
refrigerant and comprises an evaporator means and a condenser
means. Conduit means connects the evaporator to the con-
denser means. Heat exchanger means and pump means brings
the refrigerant in the evaporator means into thermal contact
with the warm water source. Heat exchanger means within the
condenser means and a pump means brings the refrigerant
vapors in the condenser means into thermal contact with the
cold water source. A pump means and conduit means returns
the condensed refrigerant, liquid, back into the evaporator
means. A liquid level control means within the evaporator
means and a divert valve means allows the refrigerant to
flow from the condenser means to the evaporator means when
the level of the refrigerant in the evaporator means when
the level of the refrigerant in the evaporator is less than
the desired level and allows the refrigerant to flow back
into the condenser means when the refrigerant level in the
evaporator means is satisfactory. A prime mover means is
interposed into the conduit means connecting the evaporator
means to the condenser means. An electrical generator means
is coupled to the said prime mover means to convert all or
part of the power developed in the prime mover means to
electrical power. An electrical control means is connected
to the electrical generator means to direct the electrical
power from the electrical generator means to the elements of
the apparatus which require electrical power, and further,
to direct excess electrical power for external usage. A
controllable valve means and conduit means is disposed in
parallel with the prime mover means, whereby the refrigerant
vapor flow can by-pass the prime mover means as a means to
control the speed of the prime mover means compensating for
variations in loads on the electrical generator means. An
optional enclosure, may enclose the heat exchanger means
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with an inlet means and an outlet means and a recirculating
pump means to provide increased heat exchanger efficiency
due to the forced circulation of the warm water source
through the enclosure.
A fundamental characteristic of the heat pump system,
of which this invention is a novel variation, comprises a
closed loop system established between an evaporator means
and a condenser means. In the case of the subject inven-
tion, the heat to the evaporator means is furnished by the
warm water source, and the cooling, or condensing, means in
the condenser means is furnished by the cold water source,
the process operating at the saturation pressures for the
refrigerant. The prime mover means is interposed in the
closed loop to provide mechanical power as well as power to
drive an electrical generator means. An electrical control
means directs electrical power to the elements of the
apparatus, and further directs excess electrical power for
external usage. A pump means, conduit means, divert valve
means and a liquid level control means return the condensed
refrigerant, liquid, to the evaporator means in a controlled
manner. The speed of the prime mover means is controlled by
a controllable valve means and conduit means in parallel
with the prime mover means.
The power developed by the said prime mover means is a
function of the pressure differential across the prime mover
means. The pressure differential is the difference between
the saturation pressure of the refrigerant in the evaporator
means, which is heated by the warm water source, and the
saturation pressure of the refrigerant in the condenser
means, which is cooled by the cold water source. Since the
prime mover is of the positive displacement type, the amount
of refrigerant vapors passing through the prime mover means
is a function of its volumetric efficiency. Therefore, it
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is desirable to use a positive displacement prime mover with
the lowest possible volumetric efficiency in order to use
the least amount of refrigerant vapors and therefore obtain
the maximum amount of generated power for the amount of heat
available.
The practice of the instant invention enables an
apparatus capable of producing mechanical power and elec-
trical power generation using water souces of low specific
energy in an efficient manner.
This invention accordingly comprises a process and an
apparatus possessing the features, properties and the
relationship of elements which will be exemplified in the
article hereinafter described, and the scope of the invention
will be indicated in the claims.
lS Brief Description of the Drawings
For a fuller understanding of the nature and objects of
the invention, reference should be had to the following
detailed description taken in connection with the accom-
panying drawing in which:
2~ Fig. 1 illustrates a specific example of the instant
invention, namely an apparatus capable cf the production of
mechanical power and electrical power generation using only
the energy available from low specific energy sources,
namely two fluid sources at different energy potentials as a
result of their differences in temperature.
sest Mode for Carrying Out the Invention
Referring now to Fig. 1, therein illustrated is one
embodiment of an apparatus for the production of mechanical
power and the production of electrical power~ which functions
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as a heat pump deriving the energy needed to sustain its own
operation, and additionally, excess power for external
usage, from two fluid sources at different energy levels as
a result of their being at different temperatures. A
distinguishing feature of this invention is that the appa-
ratus herein described and illustrated uses a positive
displacement type of prime mover which derives its power
from the pressure difference across the prime mover and
being of low volumetric efficiency, displaces a minimum of
refrigerant vapors. Since this i~s basically an adiabatic
throttling process, extremely low temperature differences
between the evaporator and condenser can be used to produce
significant power as opposed to a turbine type of prime
mover which would require large changes in enthalpy to
obtain significant power. Thus the apparatus hexein des-
cribed and illustrated can use two fluid sources at tempera-
ture differences, which have heretofore been considered
insignificant, to supply the energy necessary to power the
apparatus.
The major components of the apparatus illustrated in
Fig. 1 include an evaporator 12 which functions as a rese-
rvoir for the refrigerant 13. The pump 50 draws the refrig-
erant 13 from the evaporator 12 and by means of a conduit 54
pumps the refrigerant 12 into the heat exchanger 60 and then
returns said refrigerant 13 to the evaporator 12 through a
conduit 66, thereby bringing the refrigerant 13 into thermal
contact with the warm fluid source. A condenser 30 contains
therein a heat exchanger 32. A pump 34 draws in fluid from
the cold fluid source through a conduit 36 and pumps said
fluid through the heat exchanger 32. The cold fluid is
subsequently returned to the cold fluid source by means of a
conduit 38. A means has thus been established to bring the
cold fluid from the cold fluid source into thermal contact
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with the refrigerant vapors within the condenser 30. A
conduit 14 connects the evaporator 12 and the condenser 30.
A prime mover 24 of the posit:ive displacement type is
interposed into the conduit 14. An electrical generator 26
is coupled to the prime mover 24 to convert all or part of
the power developed in the prime mover 24 into electrical
power. An electrical control 28 directs the electrical
power produced by the electrical generator 26 to the elements
of the apparatus which require electrical power, and further
directs excess electrical energy for external usage. A
conduit 18, a conduit 22 and a controllable valve 20, placed
in parallel with the prime mover 24, control the speed of
the prime mover 24 to a constant value by the capability of
by-passing the flow of refrigerant vapors around the prime
mover 24 thus compensating for variations in loads on the
electrical generator 26. A control means 16 senses the
speed of the prime mover 24 and modulates the controllable
valve 20. A pump 42 draws condensed refrigerant vapors and
liquid from the condenser 30 through a conduit 40 and pumps
said refrigerant 13 through a conduit 44 to a divert valve
48. A liquid level control 52 is located in the evaporator
12. The liquid level control 52 maintains the desired level
of refrigerant 13 in the evaporator 12 by controlling the
divert valve 48, allowing the refrigerant 13 to flow into
the evaporator 12 by means of conduit 54 when the level of
the refrigerant 13 in the evaporator 12 is less than the
desired level, and diverting the flow of said refrigerant 13
back into the condenser 30 when the level of the refrigerant
13 in the evaporator 12 is satisfactory by means of a
conduit 46. When thermal circulation of the warm fluid
source around the heat exchanger 60 is insufficient for a
particular design or when the warm fluid source is confined,
as in the case of warm oil in a pipeline, an enclosure 58
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encloses the heat exchanger 60. This enclosure is provided
with an inlet means 62 and an outlet means 56. Flow of the
warm fluid from .he warm fluid source is induced by a
recirculating pump 64.
With further reference to Fig. 1, a specific example of
the instant invention is illustrated wherein the warm and
cold fluid sources are specifically the warm ocean surface
water and the cold deep ocean water. The closed apparatus
10 is initially evacuated of air and gas and charged with
the refrigerant 13 to be used, let us say for the purposes
of this example, ammonia. The refrigerant 13 exists as a
liquid to the level in the apparatus 10 to which it is
filled and the balance of the apparatus 10 is then filled
with the refrigerant 13 vapors at the saturation pressure
for ammonia corresponding to the temperature of the appa-
ratus 10. For example if the apparatus was 80F, the
pressure in the apparatus 10 would be the saturation pres-
sure of ammonia at 80F, or 153 psia. Operation of the
apparatus 10 is then instituted by means of auxiliary power
equipment since no electrical power exists at the electrical
control 28. Cooling or condensing water is then being
pumped through the heat exchanger 32 within the condenser 30
by the pump 34 which draws in cold deep ocean water through
conduit 36 and pumps the same to the heat exchanger 32.
After passing through the heat exchanger 32, the cold or
condensing water is returned to the ocean by means of
conduit 38. Pump 50 draws refrigerant 13 from the evapora-
tor 12 through conduit 54 and pumps the refrigerant 13 to
the heat exchanger 60. The refrigerant 13 returns to the
evaporator 12 through conduit 66. The recirculating pump 64
draws warm ocean surface water into the inlet 62 of the
enclosure 58 and discharges this flow around the heat
exchanger 60 and out of the outlet 56 of the enclosure 58.
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The refrigerant 13 is thus effectively brought into thermal
contact with a heating source, in this case warm surface
ocean water. The saturation pressure in the evaporator then
becomes the saturation pressure of the refrigerant 13 corres-
ponding to the temperature to which it is being heated bythe warm ocean surface water and the saturation pressure in
the condenser 30 is then the saturation pressure for the
refrigerant 13 in the condenser 30, corresponding to the
saturation pressure for the refrigerant 13 for the temp-
erature to which the refrigerant is being cooled by thecooling, or deep ocean water. In this example, if the
effective temperature in the evaporator 12 were to be 80F,
the pressure in the evaporator 12 portion of the apparatus
10 would be 153 psia, and if the effective temperature in
the condenser 30 were to be 60F, the pressure in the
condenser 30 portion of the apparatus 10 would be 107.6
psia, thus creating a pressure differential of 45.4 psi
across the prime move 24. The prime mover 24 is driven by
this pressure differential and the mass flow of refrigerant
vapors from the evaporator 12 to the condenser 30 would be a
function of the volumetric displacement of the prime mover
24. The electrical generator 26, driven by the prime mover
24, then provides the energy to operate the apparatus. The
condensed refrigerant vapors and liquid in the condenser 30
are returned to the evaporator 12 by means of pump 42, which
draws the refrigerant 13 from the condenser 30 through
conduit 40 and pumps this refrigerant 13 to the divert valve
48. The liquid level control 52 controls the level of the
refrigerant 13 in the evaporator by operating the divert
valve 48, allowing refrigerant 13 to flow from the divert
valve 48 to the evaporator 12 through conduit 54 when the
level of the refrigerant 13 in the evaporator 12 is less
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than the desired level and diverting the refrigerant 13
flows back into the condenser 30 through conduit 46 when
the level of the refrigerant 13 in the evaporator 12 is
satisfactory. The control 16 senses the speed of the prime
5 mover 24 and controls the controllable valve 20 to maintain
the speed of the prime mover 24 constant, compensating for
variations in loads on the electrical generator 26.
A heat pump method of producing mechanical power and
electrical power has thus been described, whereby the
temperature differentials present in the ocean, or other
warm and cold fluid sources, is the only energy required to
power the said apparatus and provide excess power and/or
electrical power for external usage.
The foregoing process and apparatus has a substantial
savings over that of the prior art in that no conventional
energy sources are required to operate the apparatus and the
apparatus utilizes energy sources of low potential, low
temperature differences, to effectively obtain significant
power production.
The present disclosure includes that contained in the
appended claims, as well as that of the foregoing descrip-
tion. Although this invention has been described in its
preferred forms with a certain degree of particularity, it
is understood that the present disclosure of the preferred
forms has been made only by way of example and numerous
changes in the details of construction and the combination
and arrangement of parts may be resorted to without depart-
ing from the spirit and scope of the invention.
