U.S. patent application number 13/935202 was filed with the patent office on 2015-01-08 for heat reclaiming refrigeration system using compound multi heat sink condenser.
The applicant listed for this patent is David A. Jones, Lance C. Laufer. Invention is credited to David A. Jones, Lance C. Laufer.
Application Number | 20150007594 13/935202 |
Document ID | / |
Family ID | 52131881 |
Filed Date | 2015-01-08 |
United States Patent
Application |
20150007594 |
Kind Code |
A1 |
Laufer; Lance C. ; et
al. |
January 8, 2015 |
Heat Reclaiming Refrigeration System Using Compound Multi Heat Sink
Condenser
Abstract
A method, and or process, of achieving a double-wall heat
recovery refrigeration condenser system, capable, within a single
compound condenser, of energy transfer to a heat recovery heat
sink, or multiple heat recovery heat sinks, as well as a heat
rejection sink, in, any combination of, or all of, the individual
heat sinks, in any ratio, requiring no change in the amount of
active working fluid, typically a refrigerant, charge requirement.
The compound condenser thus eliminates the need for working fluid
storage, and controls for controlling said storage, found in
typical multi heat sink condenser systems, and also, thus
eliminates the complexity associated with said controls and
storage. This manner of condenser is used as part of a vapor
compression refrigeration system to typically, but not exclusively,
reclaim heat from a refrigeration process, for the purpose of
heating water.
Inventors: |
Laufer; Lance C.; (Winnipeg,
CA) ; Jones; David A.; (Winnipeg, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Laufer; Lance C.
Jones; David A. |
Winnipeg
Winnipeg |
|
CA
CA |
|
|
Family ID: |
52131881 |
Appl. No.: |
13/935202 |
Filed: |
July 3, 2013 |
Current U.S.
Class: |
62/113 ;
62/498 |
Current CPC
Class: |
F28D 7/106 20130101;
F28F 2265/16 20130101; F25B 2500/01 20130101; F28D 7/0091 20130101;
F25B 2339/047 20130101; F28D 1/0461 20130101; F28D 1/0477 20130101;
F28D 7/103 20130101; F28F 1/32 20130101; F25B 39/04 20130101; F28D
7/14 20130101; F28D 2021/007 20130101; F28D 7/16 20130101; F28F
1/003 20130101 |
Class at
Publication: |
62/113 ;
62/498 |
International
Class: |
F25B 29/00 20060101
F25B029/00 |
Claims
1. A heat reclaiming refrigeration system for receiving a working
fluid therein and for cooling a target fluid, the system
comprising: a compressor device arranged to compress the working
fluid from a compressor inlet to a compressor outlet of the
compressor device; a condenser including a working passage arranged
to communicate the working fluid therethrough from a condenser
inlet to a condenser outlet of the working passage of the
condenser, the condenser inlet being in communication with the
compressor outlet so as to be arranged to receive the working fluid
therefrom; an expansion device arranged to produce a drop in
pressure in the working fluid from an expansion device inlet to an
expansion device outlet, the expansion device inlet being in
communication with the condenser outlet so as to be arranged to
receive the working fluid therefrom; and an evaporator device
including a working passage arranged to communicate the working
fluid from an evaporator inlet to an evaporator outlet of the
working passage of the evaporator, the evaporator inlet being in
communication with the expansion device outlet so as to be arranged
to receive the working fluid therefrom and the evaporator outlet
being in communication with the compressor inlet such that the
compressor inlet is arranged to receive the working fluid from the
evaporator outlet; the working passage of the evaporator device
being in heat exchanging relationship with the target fluid so as
to be arranged to transfer heat from the target fluid to the
working fluid in the working passage of the evaporator device; the
working passage of the condenser comprising a constant passage
between the condenser inlet and the condenser outlet in which at
least a section of the constant passage is in concurrent heat
exchanging relationship with: i) at least one heat reclaiming
passage receiving a respective heat reclaiming fluid therein; and
ii) a heat rejection fluid maintained separate from the heat
reclaiming fluid of said at least one heat reclaiming passage.
2. The system according to claim 1 wherein the working passage
includes a double wall boundary between the working passage and
said at least one heat reclaiming passage across which heat is
arranged to be transferred from the working fluid to the heat
reclaiming fluid, the double wall boundary comprising a pair of
boundary walls defining an externally vented safety passage
therebetween.
3. The system according to claim 1 wherein the condenser is
operable in a heat rejection mode in which a system control is
arranged to: maintain the heat reclaiming fluid of said at least
one heat reclaiming passage in a passive and non-flowing condition
in heat exchanging relationship with the working passage of the
condenser; and maintain the heat rejection fluid in an active and
flowing condition in heat exchanging relationship with the working
passage of the condenser.
4. The system according to claim 1 wherein the condenser is
operable in a heat reclaiming mode in which a system control is
arranged to: maintain the heat reclaiming fluid of said at least
one heat reclaiming passage in an active and flowing condition in
heat exchanging relationship with the working passage of the
condenser; and maintain the heat rejection fluid in a passive and
non-flowing condition in heat exchanging relationship with the
working passage of the condenser.
5. The system according to claim 1 wherein the condenser is
operable in a combined heat rejection and heat reclaiming mode in
which a controller of the system is arranged to: maintain the heat
reclaiming fluid of said at least one heat reclaiming passage in an
active and flowing condition in heat exchanging relationship with
the working passage of the condenser; and maintain the heat
rejection fluid in an active and flowing condition in heat
exchanging relationship with the working passage of the
condenser.
6. The system according to claim 1 wherein the working passage is
in concurrent heat exchanging relationship with both the heat
rejection fluid and the heat reclaiming fluid of said at least one
heat reclaiming passage along a full length of the working
passage.
7. The system according to claim 1 wherein a common section of the
working passage is in concurrent heat exchanging relationship with
both the heat rejection fluid and the heat reclaiming fluid of said
at least one heat reclaiming passage and at least one auxiliary
section of the working passage is in heating relationship with only
one of the heat rejection fluid and the heat reclaiming fluid of
said at least one heat reclaiming passage.
8. The system according to claim 1 wherein the heat rejection fluid
and the heat reclaiming fluid of said at least one heat reclaiming
passage are arranged in heat exchanging relationship through
different boundary walls of the working passage of the
condenser.
9. The system according to claim 8 wherein the working passage of
the condenser comprises a generally annular passage defined between
an outer tubular wall assembly and at least one inner tubular wall
assembly extending longitudinally within the outer tubular wall
assembly, and wherein the heat rejection fluid and the heat
reclaiming fluid of said at least one heat reclaiming passage are
arranged such that the heat rejection fluid is in heat exchanging
relationship with the working fluid through one of the outer
tubular wall assembly and said at least one inner tubular wall
assembly and the heat reclaiming fluid is in heat exchanging
relationship through another one of the outer tubular wall assembly
and said at least one inner tubular wall assembly which is
different than the heat rejection fluid.
10. The system according to claim 8 wherein the heat rejection
fluid comprises air in heat exchanging relationship with the
working fluid through an outermost boundary of the working passage
of the condenser.
11. The system according to claim 1 wherein: the working passage of
the condenser includes a generally annular portion defined between
an outer tubular wall assembly and at least one inner tubular wall
assembly extending longitudinally within the outer tubular wall
assembly; said at least one inner tubular wall assembly defining a
respective first auxiliary passage bound by said at least one inner
tubular wall assembly; the condenser further comprises an auxiliary
tubular wall receiving the outer tubular wall assembly
substantially concentrically therethrough to define a second
auxiliary passage bound between the auxiliary tubular wall and the
outer tubular wall assembly; and the heat rejection fluid and the
heat reclaiming fluid of said at least one heat reclaiming passage
being arranged such that the heat rejection fluid is in heat
exchanging relationship with the working fluid through one of the
outer tubular wall assembly and said at least one inner tubular
wall assembly and the heat reclaiming fluid is in heat exchanging
relationship through another one of the outer tubular wall assembly
and said at least one inner tubular wall assembly which is
different than the heat rejection fluid.
12. The system according to claim 1 wherein said at least one heat
reclaiming passage comprises a plurality of heat reclaiming
passages, each receiving a respective heat reclaiming fluid
therein, and wherein the heat rejection fluid and each heat
reclaiming fluid are arranged in heat exchanging relationship
through respective different boundaries of the working passage of
the condenser.
13. The system according to claim 12 further comprising an outer
tubular wall assembly and a plurality of independent inner tubular
wall assemblies extending alongside one another longitudinally
within the outer tubular wall assembly such that: the working
passage of the condenser is defined between the outer tubular wall
assembly and the plurality of independent inner tubular wall
assemblies extending longitudinally within the outer tubular wall
assembly; the heat rejection fluid is in heat exchanging
relationship with the working fluid through the outer tubular wall
assembly; and each heat reclaiming fluid is located in a respective
one of the inner tubular wall assemblies so as to be in heat
exchanging relationship with the working fluid through the
respective inner tubular wall assembly.
14. The system according to claim 1 further comprising a heat
reclaiming circuit in communication between said at least one heat
reclaiming passage of the condenser and a storage device for
storing heat reclaiming fluid therein which has been circulated
through said at least one heat reclaiming passage by the heat
reclaiming circuit.
15. The system according to claim 14 in combination with a
plurality of usage devices, each usage device including a usage
circuit in communication with the storage device and a controller
for controlling circulation of the usage circuit between the
storage device and the respective usage device according to a
respective heat demand of the respective usage device.
16. The system according to claim 1 wherein said at least one heat
reclaiming passage includes a heat reclaiming fluid mover
associated therewith and arranged to induce a flow of the heat
reclaiming fluid through the heat reclaiming passage, a reclaim
temperature sensor device for determining a temperature of the heat
reclaiming fluid prior to entering the condenser, and a system
control arranged to increase operation of the heat reclaiming fluid
mover in response to the temperature of the heat reclaiming fluid
sensed by the reclaim temperature sensor device being below a
prescribed target temperature.
17. The system according to claim 16 further comprising a
condensing condition sensor device arranged to determine a
condensing condition of the working fluid, a system control being
arranged to decrease operation of the heat reclaiming fluid mover
in response to the condensing condition being below a prescribed
lower limit.
18. The system according to claim 16 further comprising a heat
rejection fluid mover associated with the heat rejection fluid and
arranged to induce a flow of the heat rejection fluid across a
boundary of the working passage of the condenser and a condensing
condition sensor device arranged to determine a condensing
condition of the working fluid, a system control being arranged to
increase operation of the heat rejection fluid mover in response to
the condensing condition being above a prescribed upper limit.
19. The system according to claim 18 wherein the prescribed upper
limit is greater than a target condensing condition corresponding
to optimal cooling efficiency.
20. The system according to claim 1 further comprising a heat
rejection fluid mover associated with the heat rejection fluid and
arranged to induce a flow of the heat rejection fluid across a
boundary of the working passage of the condenser and a condensing
condition sensor device arranged to determine a condensing
condition of the working fluid, a system control being arranged to
increase operation of the heat rejection fluid mover in response to
the condensing condition being above a prescribed upper limit if a
heating demand on the heat reclaiming fluid of said at least one
heat reclaiming passage has been met.
21. A method of reclaiming heat from a refrigeration system using a
working fluid for cooling a target fluid, the method comprising: i)
providing a refrigeration system comprising: a) a compressor device
arranged to compress the working fluid from a compressor inlet to a
compressor outlet of the compressor device; b) a condenser
including a working passage arranged to communicate the working
fluid therethrough from a condenser inlet to a condenser outlet of
the working passage of the condenser, the condenser inlet being in
communication with the compressor outlet so as to be arranged to
receive the working fluid therefrom; c) an expansion device
arranged to produce a drop in pressure in the working fluid from an
expansion device inlet to an expansion device outlet, the expansion
device inlet being in communication with the condenser outlet so as
to be arranged to receive the working fluid therefrom; and d) an
evaporator device including a working passage arranged to
communicate the working fluid from an evaporator inlet to an
evaporator outlet of the working passage of the evaporator, the
evaporator inlet being in communication with the expansion device
outlet so as to be arranged to receive the working fluid therefrom
and the evaporator outlet being in communication with the
compressor inlet such that the compressor inlet is arranged to
receive the working fluid from the evaporator outlet, and the
working passage of the evaporator device being in heat exchanging
relationship with the target fluid so as to be arranged to transfer
heat from the target fluid to the working fluid in the working
passage of the evaporator device; ii) providing the working passage
of the condenser in the form of a constant passage between the
condenser inlet and the condenser outlet which is in concurrent
heat exchanging relationship with: a) at least one heat reclaiming
passage receiving a respective heat reclaiming fluid therein; and
b) a heat rejection fluid maintained separate from the heat
reclaiming fluid of said at least one heat reclaiming passage; iii)
arranging the condenser to be operable in a heat reclaiming mode
when heating demands on the heat reclaiming fluid are sufficient to
maintain efficient operation of the condenser by maintaining the
heat reclaiming fluid of said at least one heat reclaiming passage
in an active and flowing condition in heat exchanging relationship
with the working passage of the condenser, and by maintaining the
heat rejection fluid in a passive and non-flowing condition in heat
exchanging relationship with the working passage of the condenser;
iv) arranging the condenser to be operable in a heat rejection mode
when heating demands on the heat reclaiming fluid have been met by
maintaining the heat reclaiming fluid of said at least one heat
reclaiming passage in a passive and non-flowing condition in heat
exchanging relationship with the working passage of the condenser,
and maintaining the heat rejection fluid in an active and flowing
condition in heat exchanging relationship with the working passage
of the condenser; and v) arranging the condenser to be operable in
a combined heat rejection and heat reclaiming mode when heating
demands on the heat reclaiming fluid have not been met but are
insufficient alone to maintain efficient operation of the condenser
by maintaining the heat reclaiming fluid of said at least one heat
reclaiming passage in an active and flowing condition in heat
exchanging relationship with the working passage of the condenser,
and maintaining the heat rejection fluid in an active and flowing
condition in heat exchanging relationship with the working passage
of the condenser.
22. The method according to claim 21 including maintaining a fixed
active charge of working fluid throughout operation in either the
heat reclaiming mode, the heat rejection mode, or the combined heat
rejection and heat reclaiming mode regardless of the ratio of heat
transfer to the heat rejection fluid and heat transfer to the heat
reclaiming fluid in the combined heat rejection and heat reclaiming
mode.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to refrigeration vapor
compression condenser heat exchangers used in refrigeration systems
for heat recovery, and more particularly the present invention
relates to a compound condenser for transferring condenser heat
energy concurrently to multiple heat sinks via separate heat
transfer fluids. According to a preferred embodiment, the compound
condenser includes a double wall so as to be well suited for either
potable or non-potable heat recovery.
BACKGROUND
[0002] In the typical vapor compression refrigeration system,
various components, such as the compressor, condenser, evaporator
and expansion devices, are arranged to transfer heat energy between
a fluid in a heat exchange relationship with an evaporator (also
known as the heat source) and a fluid in heat exchange relation
with the condenser (also known as the heat sink).
[0003] It is also known in conjunction with such refrigeration
systems to utilize multiple heat exchangers on the discharge,
condenser side, of the compressor as desuperheaters and or
condensers to transfer the heat from the condensing refrigerant,
also known as working fluid, to multiple heat sinks. Often one or
more of these heat exchangers are used for the purpose of heat
reclaim, such as water heating.
[0004] Typical applications include the use of standard
air-conditioning units to heat swimming pools and the use of
refrigeration or cooling units to heat potable or non potable hot
water. Applications are common in industrial, commercial,
institutional and residential installations when there is a
somewhat coincidental need for both cooling and heat.
[0005] However, such known systems have several drawbacks that have
inhibited their full commercial acceptance. Principal among such
drawbacks are the difficulty of design and the complexity of the
heat exchangers and related controls to allow the system to perform
effectively over the normal expected operating ranges of the
equipment.
[0006] The magnitude of the complexity is evidenced by the multiple
patents for controls, devices and systems, related to design and
control of these systems. Therefore, there is a need for a
simplified system that allows the transfer of heat to multiple heat
sink fluids in the same vapor compression refrigeration system.
[0007] The vapor compression refrigeration system was first
described in detail, but never built, by Oliver Evans in 1805.
British Patent No. 6662 was granted to Jacob Perkins for the vapor
compression refrigeration system in 1835. The working prototype,
using ether as a refrigerant, had an evaporator vessel submerged in
liquid that provided the heat to vaporize the refrigerant, the
gaseous refrigerant was drawn from the evaporator and compressed
with a hand operated compressor, the compressed refrigerant was
passed through tubing in water where it condensed, the condensed
liquid refrigerant was then passed through a pressure reduction
valve to start the cycle again. This system contained what has
remained the four principle features of a refrigeration system
still common today: the evaporator; the compressor; the condenser;
and, the expansion device.
[0008] A typical vapor compression refrigeration system is shown in
FIG. 1 using liquid source to liquid heat sink as per Perkins.
However, this schematic could also depict liquid, gas, or solid
sources, to liquid, gas, or solid heat sinks, in any combination.
Also included is a representation showing liquid to gas proportions
and energy movement in the condenser 3. Energy is transferred from
an energy (heat) source to the working fluid normally a
refrigerant, in an evaporator 1, causing it to evaporate. This
gaseous working fluid moves to a compressive device 2 where the
pressure is raised, with the associated increase in temperature.
This compressed gaseous working fluid then moves to the condenser 3
where the energy is transferred from the working fluid through the
condenser to a heat sink fluid causing the gaseous working fluid to
condense. The liquid working fluid is returned to the evaporator,
through an expansion device 4, to begin the cycle again.
[0009] These systems are common, simple, and generally problem
free. They are the basis of modern refrigeration vapor compression
systems from air-conditioners to artificial ice plants and
everything in between. These systems are ubiquitous in our modern
life, found in our homes, our businesses, and even our
transportation.
[0010] A vapor compression refrigeration system is a heat transfer
device, i.e. a heat pump. In operation there will always be a
reduction of energy, or cooling, on the evaporator or source side
of the system and an increase in energy, heat, on the condenser or
heat sink side of the system. Although highly efficient in
providing heating or cooling as a single product, the use of both
simultaneously has always intrigued learned people.
[0011] Since early in the invention of the refrigeration, heat
pump, cycle, learned people have been struggling to take advantage
of the heat rejection part of the process to heat fluids, either
directly, or more advantageously, as a free by-product of a needed
cooling process. The challenge from the beginning has been that in
order to use a simple refrigeration system as taught by Perkins,
for simultaneous heating and cooling the need for heating and
cooling must occur at the same time, be coincidental, and there
must be sufficient cooling and heating loads to allow the system to
operate correctly. If either of the loads is insufficient, there is
a load differential. If there is a load differential or the loads
are not coincidental the total system operation will suffer. The
challenge was apparent to the learned as the patent record shows.
The evolution to the multi condenser refrigeration system can be
clearly seen in the patent record of refrigeration devices used to
heat water.
[0012] The first teaching on heat reclaim is U.S. Pat. No.
1,331,600 to Wales for a combination cooler water heater. In order
to address the differential and coincidental load challenge, Wales
limited the amount of water in the hot water tank as well as
providing for a brine cooling thermal mass in the cooler. With the
use of controlled storage, excess cooling could be stored in the
brine thermal mass, and a shortage of condenser energy to properly
heat the water could be overcome by reducing the amount of water.
Thus both coincidental and differential load problems could be
reduced, however they were not necessarily eliminated.
[0013] Unfortunately, as can be imagined, even with the benefits
provided by the brine and the storage tank, the system would not
necessarily provide sufficient heating and or cooling at all times
in all applications. The system was capable of levelling the loads;
it was not capable of addressing fundamental differences in the
loads.
[0014] The result is that in the later teachings in U.S. Pat. No.
2,042,812 to Tull, the need for a coincidental load was removed by
not specifically using the cooling from the device, in effect
wasting the cooling. This system basically heated water with the
energy available around the unit. No attempt was made to use the
cooling. Some would say a regression in efficient energy usage but
an advancement in ensuring that the water heating demand would be
met.
[0015] In U.S. Pat. No. 2,095,017 to Wilkes the system was once
again taught as providing cooling to the room and electric
supplemental heat was added to increase water temperature and as a
means to ensure hot water production met demand.
[0016] In U.S. Pat. No. 2,375,157 again to Wilkes, his previous
patent was expanded with teaching on the use of two evaporators
connected to two separate heat sources connected to a single hot
water generating system. One can imagine that Wilkes recognized
that some of the electric heat used in the water tank of his
previous patent could be offset if there was more cooling
demand.
[0017] In U.S. Pat. No. 2,632,306 to Ruff, the teaching provides a
solution for the problem of maintaining cooling when no hot water
demand exists. This was achieved by bleeding hot water and
artificially creating a hot water demand to provide demand
cooling.
[0018] In U.S. Pat. No. 3,188,829 to Siewert, an additional
air-cooled heat exchanger is provided in series with the hot water
heat exchanger condenser that acts as the condenser when the demand
for hot water has been met. This is a dual heat sink design with
the first heat sink being hot water that is heated and the second
heat sink is the air that is heated with the excess heat. The
second heat sink ensures that the need for cooling is always met
when there is no coincidental demand for hot water.
[0019] Siewert's teachings ensured that there was no need for
coincidental heating of water when cooling was required. This not
only ensured that cooling demand was met, but it can reasonably be
seen how it could actually increase the total amount of water that
could be heated as well, as explained below.
[0020] Because the need for balanced coincidental loads had been
eliminated, the water heating apparatus could be added to cooling
systems which had much greater capacity than the capacity needed
just for water heating. With the greater amount of heat available,
more water heating could be done when there was coincidental
need.
[0021] However, Siewert was now moving away from the simple system
as taught by Perkins, and the refrigeration system modifications
would end up becoming far more complex than simply the addition of
another condenser.
[0022] One of the key considerations for proper operation of a
vapor compression refrigeration system is that the working fluid
should be completely liquefied before it enters the expansion
device. This ensures that all of the energy that was absorbed by
the working fluid in the evaporator through evaporation has been
transferred to the condenser through the condensation process, and
also that the expansion device works properly. This process of
making the gaseous working fluid a liquid occurs in the
condenser(s) of a typical vapor compression refrigeration system.
To ensure that the working fluid is a liquid the condenser normally
cools the working fluid down below its saturation temperature, also
known as subcooling. In order for the leaving liquid working fluid
to be sub cooled, some portion of the condenser must be filled with
liquid working fluid that is being cooled past the condensing
temperature.
[0023] If there is too little liquid working fluid in the
condenser, the proper sub cool design point will not be reached and
system operation and performance will be affected negatively. If
there is too much liquid working fluid in the condenser, the
condensing heat transfer area is reduced also affecting operation
and performance in a negative manner. Thus maintaining the designed
liquid to gas proportions in the condenser, over the normal
operating range of the system, is a very important aspect of
optimizing system performance.
[0024] With a simple refrigeration system, i.e. a system having one
evaporator, and one condenser, the system can typically be designed
so that through the expected operating ranges of the equipment, the
active operating working fluid charge requirements do not vary
beyond the systems ability to accommodate the change.
[0025] However, with more complex refrigeration systems designed
with multiple condensers, and multiple heat sinks, typically,
achieving a fixed unchanging active refrigeration charge is not as
easy, resulting in the need for added controls and or working fluid
storage.
[0026] FIG. 2 shows a system schematic for an air source to a
liquid heat sink and then to an air heat sink as per Siewert.
However, this schematic could also depict liquid, gas, or solid
sources, to liquid, gas, or solid first heat sinks, followed by
liquid, gas, or solid second heat sinks, in any combination. This
schematic depicts the first heat exchanger operating as a
desuperheater (a device that removes energy from the working fluid
but does not cool the working fluid enough so that it will
condense) and the second operating as the condenser. Also included
is a representation showing liquid to gas proportions and energy
movement in the condensers.
[0027] The various steps of the process are described as follows.
Energy is transferred from an energy (heat) source to the working
fluid, in an evaporator 1, causing it to evaporate. This gaseous
working fluid moves to a compressive device 2 where the pressure is
raised, with the associated increase in temperature. The compressed
gaseous working fluid then moves to the first series heat
exchanger, 3A, which is operating as a desuperheater, where
sensible energy can be transferred from the gaseous working fluid
to the first heat sink fluid. This energy transfer is not enough to
cause the gaseous working fluid to condense. The gaseous working
fluid then moves to the next series heat exchanger, 3B, which is
operating as a condenser where energy is transferred from the
gaseous working fluid through the condenser to a single, second
heat sink fluid causing the gaseous working fluid to condense. The
liquid working fluid is returned to the evaporator, through an
expansion device 4, to begin the cycle again.
[0028] FIG. 3 schematically represents the same simplified series
multiple condenser vapor compression circuit as shown in FIG. 2,
but with the first heat exchanger, 3A, operating as a condenser,
and the second heat exchanger, 3B, operating as a subcooler or
simply a refrigeration passage. Also depicted are liquid/gas
proportions and energy movement representation in the heat
exchangers.
[0029] The various steps of the process are described as follows.
Energy is transferred from an energy (heat) source to the liquid
working fluid, in an evaporator 1, causing it to evaporate. This
gaseous working fluid moves to a compressive device 2 where the
pressure is raised, with the associated increase in temperature.
This compressed gaseous working fluid then moves to the first heat
exchanger, 3A, which is operating as a condenser where the energy
is transferred from the gaseous working fluid through the condenser
to a heat sink fluid causing the gaseous working fluid to condense,
the working fluid is generally further cooled sensibly in this heat
exchanger (subcooled) before it moves to the next heat exchanger,
3B, which can operate as a sub-cooler where further sensible energy
can be transferred to the second heat sink fluid or a working fluid
passage where no changes are made to the energy content of the
working fluid. The liquid working fluid is returned to the
evaporator, through an expansion device 4, to begin the cycle
again.
[0030] In the series condenser system, all of the working fluid
goes through all of the heat exchangers in series, allowing all of
the working fluid to contact all of the heat sink fluids. As the
energy in the gaseous working fluid is released to the condenser
the working fluid becomes a liquid. In a series condenser system,
three possible operational modes can be envisioned: 1) All of the
condensing working fluid energy is transferred in the second heat
exchanger; 2) All of the condensing working fluid energy is
transferred in the first heat exchanger; 3) Some of the energy is
transferred in each of the heat exchangers.
[0031] In the first case, if all of the condensing working fluid
energy is transferred in the second heat exchanger which is
operating as a condenser the first heat exchanger must be full of
gaseous working fluid, as no condensing has taken place.
[0032] In the second case, if all of the condensing working fluid
energy is transferred in the first heat exchanger which is
operating as a condenser then all of the working fluid leaving the
first heat exchanger must be liquid. This results in the second
heat exchanger being completely full of liquid working fluid as the
working fluid entering is liquid, and the working fluid leaving
must be liquid.
[0033] In the third case there will be a condition in between the
two extremes of the first case and the second case.
[0034] In comparing the first case and the second case, it is clear
that the volume of liquid working fluid in each case is very
different. In each case the heat exchanger that is acting as the
condenser will have roughly the same amount of liquid working
fluid. In the first case the other heat exchanger is completely
full of gaseous working fluid in the second case it is completely
full of liquid working fluid.
[0035] In FIG. 2 and FIG. 3, this can be seen clearly by comparing
the liquid gas ratio representations. It can be seen that a
refrigeration system would need more working fluid to operate in
case two (FIG. 3), than in case one (FIG. 2). It can also be
envisioned that a refrigeration system with enough working fluid to
operate in case two would not operate properly in case one.
[0036] To avoid the issues that must be addressed with the changing
working fluid charge requirements of these multi heat sink multi
condenser systems, it is very common for the first condenser to be
operated strictly as a desuperheater, a device that transfers a
limited amount of energy, that is insufficient to cause the working
fluid to condense, and there are many patents teaching designs and
controls on this subject. The disadvantages of this operation is
that only a fraction of the energy can be transferred to the first
heat sink, and the second heat sink must always be operated.
[0037] If the first heat exchanger is designed to be both
desuperheater and condenser at different times or in varying
ratios, the changes in the required working fluid charge must be
addressed by the addition of extra controls and devices.
[0038] Siewert recognized the issues associated with the changing
active working fluid charge requirements within his design and a
great deal of the patent is used to address the components and
controls required to properly control these varying active working
fluid charges. This is why the refrigeration system shown in FIG.
4, a copy of the drawing in Siewert, modified for comparison, is
far more complex than the idealized systems represented in FIGS. 2
and 3.
[0039] FIG. 4 shows the same simplified series flow multiple
condenser vapor compression circuit schematic with the added
controls and devices as taught by Siewert. Items 5-9 have been
added to FIG. 2 and FIG. 3. The various steps in the process are
described as follows. Energy is transferred from an energy (heat)
source to the liquid working fluid, in an evaporator 1, causing it
to evaporate. This gaseous working fluid moves to a compressive
device 2 where the pressure is raised, with the associated increase
in temperature. The compressed gaseous working fluid then moves to
the series heat exchangers that can operate in several modes: In
the first mode, the first heat exchanger, 3A, operates as a
desuperheater, the second heat exchanger, 3B, operates as a
condenser and subcooler; In the second mode, the first heat
exchanger, 3A, operates as a condenser and the second heat
exchanger, 3B, operates as a sub cooler; And finally, in the third
mode, the first heat exchanger, 3A, operates as a condenser and the
second heat exchanger, 3B, operates as a working fluid passage.
Energy is transferred from the gaseous working fluid through the
heat exchangers to the heat sink(s), causing the working fluid to
condense. The liquid working fluid is returned to the evaporator,
through an expansion device 4 to begin the cycle again. Additional
components included are: a bypass control valve 5; regulating means
6 for controlling operation of 3B; a working fluid receiver
(working fluid storage device) 7; a pressure responsive valve 8
operable to maintain predetermined minimum system pressure at
working fluid storage device 7; and, an on-off control valve 9 to
regulate operation of the pressure responsive valve 8.
[0040] Subsequent patents, which have been many, have maintained
the multiple condenser teaching of Siewert. These later teachings
have modified the hot water condenser auxiliary condenser
arrangement, have introduced parallel condenser designs, have added
additional controls for better operation, and taught of different
water heating. However, all of the subsequent teachings on this
subject have maintained the concept of 2 or more individual heat
exchangers capable of being condensers and or desuperheaters, at
least one of which heats water.
[0041] Although such systems have proven effective at reclaiming
and conserving energy, these systems have several fundamental
disadvantages that have prevented more widespread acceptance as
noted in the following:
[0042] 1) The multiple operating parameters associated with
differing condensing conditions that range from cold water to no
water, have a large variable effect on the liquid to gas working
fluid proportions in the condensers, resulting in a general
requirement for different amounts of active working fluid in the
system at different operating conditions. These changes in the
required amounts of active working fluid require controls and
mechanisms for determining when the amount of active working fluid
should change, methods of adding and removing working fluid from
the active system, and apparatus to store the extra working
fluid.
[0043] 2) These systems tend to require significantly more working
fluid than standard cooling systems, which is an environmental
challenge.
[0044] 3) With the multiple condensers, the controls to operate
each, as well as the controls and apparatus described in point 1
above, most such systems are complicated and expensive.
[0045] 4) In practice, because of the complexity and the
variability of operating conditions, service and repair of these
systems has been much more difficult.
SUMMARY OF THE INVENTION
[0046] The present invention provides a process, and or method of
achieving a multi heat sink, heat-recovery compound condenser with
a fixed active working fluid charge requirement, capable of
eliminating the need for the refrigeration controls and devices
that control system working fluid volume typically needed in these
systems. This is achieved by having one condenser with additional
heat sink fluid heat transfer path(s) within said condenser. These
additional heat sink fluid heat transfer paths, when used for heat
recovery, are the means of reclaiming the available heat and
transferring it to a fluid which can be used to supply heat. The
heat-recovery heat sink fluid could be used directly or it could be
connected indirectly to the usage device(s) through storage or heat
exchange device(s). With such path(s) in place, the condensing
working fluid is in contact with both the heat recovery heat sink
heat transfer fluid(s) and the heat rejection heat sink heat
transfer fluid(s) in such a manner that the condensing working
fluid is unaffected by the ratio of the energy going to the
individual heat sinks. This method would typically simplify
controls, reduce the number of components, reduce the refrigeration
charge, and simplify servicing of a refrigeration system, in
comparison to other multi heat sink condenser methods with similar
functionality.
[0047] According to one aspect of the invention there is provided a
heat reclaiming refrigeration system for receiving a working fluid
therein and for cooling a target fluid, the system comprising:
[0048] a compressor device arranged to compress the working fluid
from a compressor inlet to a compressor outlet of the compressor
device;
[0049] a condenser including a working passage arranged to
communicate the working fluid therethrough from a condenser inlet
to a condenser outlet of the working passage of the condenser, the
condenser inlet being in communication with the compressor outlet
so as to be arranged to receive the working fluid therefrom;
[0050] an expansion device arranged to produce a drop in pressure
in the working fluid from the expansion device inlet to the
expansion device outlet, the expansion device inlet being in
communication with the condenser outlet so as to be arranged to
receive the working fluid therefrom; and
[0051] an evaporator device including a working passage arranged to
communicate the working fluid from an evaporator inlet to an
evaporator outlet of the working passage of the evaporator, the
evaporator inlet being in communication with the expansion device
outlet so as to be arranged to receive the working fluid therefrom
and the evaporator outlet being in communication with the
compressor inlet such that the compressor inlet is arranged to
receive the working fluid from the evaporator outlet;
[0052] the working passage of the evaporator device being in heat
exchanging relationship with the target fluid so as to be arranged
to transfer heat from the target fluid to the working fluid in the
working passage of the evaporator device;
[0053] the working passage of the condenser comprising a constant
passage between the condenser inlet and the condenser outlet which
is in concurrent heat exchanging relationship with: [0054] i) at
least one heat reclaiming passage receiving a respective heat
reclaiming fluid therein; and [0055] ii) a heat rejection fluid
maintained separate from the heat reclaiming fluid of said at least
one heat reclaiming passage.
[0056] In the preferred embodiment, the working passage includes a
double wall boundary between the working passage and said at least
one heat reclaiming passage across which heat is transferred from
the working fluid to the heat reclaiming fluid. Preferably these
boundary walls will be in tight physical contact, possibly with
surface enhancements, in order for the heat to be effectively
transferred by conduction from one wall to the other. The safety
passage between these walls will be vented externally, such as
being open to the atmosphere. In the event of a breach of either of
the walls the escaping fluid will move through the boundary and out
of the system.
[0057] Preferably the condenser is operable in a heat rejection
mode, a heat reclaiming mode, or a combined heat rejection and heat
reclaiming mode.
[0058] In the heat rejection mode a controller of the system is
arranged to: [0059] maintain the heat reclaiming fluid of said at
least one heat reclaiming passage in a passive and non-flowing
condition in heat exchanging relationship with the working passage
of the condenser; and [0060] maintain the heat rejection fluid in
an active and flowing condition in heat exchanging relationship
with the working passage of the condenser.
[0061] In the heat reclaiming mode the controller of the system is
arranged to: [0062] maintain the heat reclaiming fluid of said at
least one heat reclaiming passage in an active and flowing
condition in heat exchanging relationship with the working passage
of the condenser; and [0063] maintain the heat rejection fluid in a
passive and non-flowing condition in heat exchanging relationship
with the working passage of the condenser.
[0064] In the combined heat rejection and heat reclaiming mode the
controller of the system is arranged to:
[0065] maintain the heat reclaiming fluid of said at least one heat
reclaiming passage in an active and flowing condition in heat
exchanging relationship with the working passage of the condenser;
and
[0066] maintain the heat rejection fluid in an active and flowing
condition in heat exchanging relationship with the working passage
of the condenser.
[0067] According to a second aspect of the present invention there
is provided a method of reclaiming heat from a refrigeration system
using a working fluid for cooling a target fluid, the method
comprising:
[0068] i) providing a refrigeration system comprising: [0069] a) a
compressor device arranged to compress the working fluid from a
compressor inlet to a compressor outlet of the compressor device;
[0070] b) a condenser including a working passage arranged to
communicate the working fluid therethrough from a condenser inlet
to a condenser outlet of the working passage of the condenser, the
condenser inlet being in communication with the compressor outlet
so as to be arranged to receive the working fluid therefrom; [0071]
c) an expansion device arranged to produce a drop in pressure in
the working fluid from an expansion device inlet to an expansion
device outlet, the expansion device inlet being in communication
with the condenser outlet so as to be arranged to receive the
working fluid therefrom; and [0072] d) an evaporator device
including a working passage arranged to communicate the working
fluid from an evaporator inlet to an evaporator outlet of the
working passage of the evaporator, the evaporator inlet being in
communication with the expansion device outlet so as to be arranged
to receive the working fluid therefrom and the evaporator outlet
being in communication with the compressor inlet such that the
compressor inlet is arranged to receive the working fluid from the
evaporator outlet, and the working passage of the evaporator device
being in heat exchanging relationship with the target fluid so as
to be arranged to transfer heat from the target fluid to the
working fluid in the working passage of the evaporator device;
[0073] ii) providing the working passage of the condenser in the
form of a constant passage between the condenser inlet and the
condenser outlet which is in concurrent heat exchanging
relationship with: [0074] a) at least one heat reclaiming passage
receiving a respective heat reclaiming fluid therein; and [0075] b)
a heat rejection fluid maintained separate from the heat reclaiming
fluid of said at least one heat reclaiming passage;
[0076] iii) arranging the condenser to be operable in a heat
reclaiming mode when heating demands on the heat reclaiming fluid
are sufficient to maintain efficient operation of the condenser by
maintaining the heat reclaiming fluid of said at least one heat
reclaiming passage in an active and flowing condition in heat
exchanging relationship with the working passage of the condenser,
and by maintaining the heat rejection fluid in a passive and
non-flowing condition in heat exchanging relationship with the
working passage of the condenser;
[0077] iv) arranging the condenser to be operable in a heat
rejection mode when heating demands on the heat reclaiming fluid
have been met by maintaining the heat reclaiming fluid of said at
least one heat reclaiming passage in a passive and non-flowing
condition in heat exchanging relationship with the working passage
of the condenser, and maintaining the heat rejection fluid in an
active and flowing condition in heat exchanging relationship with
the working passage of the condenser; and
[0078] v) arranging the condenser to be operable in a combined heat
rejection and heat reclaiming mode when heating demands on the heat
reclaiming fluid have not been met but are insufficient alone to
maintain efficient operation of the condenser by maintaining the
heat reclaiming fluid of said at least one heat reclaiming passage
in an active and flowing condition in heat exchanging relationship
with the working passage of the condenser, and maintaining the heat
rejection fluid in an active and flowing condition in heat
exchanging relationship with the working passage of the
condenser.
[0079] The present invention overcomes the disadvantages of the
prior art systems in several aspects. In operation, the disclosed
design provides a means for the condensing working fluid to be in
simultaneous, thermal contact with two or more heat sink heat
transfer fluids. In addition, the disclosed system is capable of
transferring energy to any one, any combination of, or all of, the
individual heat sink heat transfer fluids, in any ratio, within the
same condenser structure.
[0080] Furthermore, because the condensing process of the working
fluid in the disclosed multi heat sink compound condenser is
independent of the ratio of energy going to the different heat
sinks there is no condenser impact on the needed operational active
working fluid charge, resulting from the varying ratios of energy
going to each of the heat sink heat transfer fluids. With no
variation in operational charge required by the condenser the
refrigeration system will operate over the design operation range
on a fixed refrigeration charge in the same manner as a single heat
sink condenser without the additional: refrigeration controls;
refrigeration devices; refrigeration storage; and, extra working
fluid associated with prior art multi heat sink refrigeration
systems.
[0081] In short, the disclosed invention allows a multi heat sink
compound condenser to be as simple, from a refrigeration design
perspective, as the original vapor compression system patented by
Perkins in 1834. Using the disclosed invention, multi heat sink
condenser systems, once correctly designed, will operate over their
designed operating ranges with fixed active operating working fluid
charges, just as a single heat sink condenser system does.
[0082] The percentage of energy going to each heat sink can be
adjusted by varying the flow of heat transfer fluids to the
associated heat sinks in such a manner that is advantageous for the
intended purpose.
[0083] In some embodiments, a common section of the working passage
is in concurrent heat exchanging relationship with both the heat
rejection fluid and the heat reclaiming fluid of said at least one
heat reclaiming passage along a full length of the working
passage.
[0084] Alternatively, the common section of the working passage
which is in concurrent heat exchanging relationship with both the
heat rejection fluid and the heat reclaiming fluid may extend along
only a portion of the length so that one or more auxiliary sections
of the working passage in series with the common section is in
heating relationship with only one of the heat rejection fluid and
the heat reclaiming fluid of said at least one heat reclaiming
passage. For example, one auxiliary section of the working passage
immediately adjacent the condenser inlet may be in heat exchanging
relationship with only the heat reclaiming fluid corresponding to a
desuperheating zone of the condenser.
[0085] Preferably the heat rejection fluid and the heat reclaiming
fluid of said at least one heat reclaiming passage are arranged in
heat exchanging relationship through different boundary walls of
the working passage of the condenser.
[0086] The working passage of the condenser may comprise a
generally annular passage defined between an outer tubular wall
assembly and at least one inner tubular wall assembly extending
longitudinally within the outer tubular wall assembly. In this
instance, the heat rejection fluid and the heat reclaiming fluid of
said at least one heat reclaiming passage are arranged such that
the heat rejection fluid is in heat exchanging relationship with
the working fluid through one of the inner and outer tubular wall
assemblies and the heat reclaiming fluid is in heat exchanging
relationship through another one of the inner and outer tubular
wall assemblies which is different than the heat rejection
fluid.
[0087] When the heat rejection fluid comprises air, preferably the
heat rejection fluid is in heat exchanging relationship with the
working fluid through an outermost boundary of the working passage
of the condenser.
[0088] When the working passage of the condenser includes a
generally annular portion defined between an outer tubular wall
assembly and at least one inner tubular wall assembly extending
longitudinally within the outer tubular wall, preferably said at
least one inner tubular wall assembly defines a respective first
auxiliary passage bound by said at least one inner tubular wall
assembly. The condenser may further comprise an auxiliary tubular
wall receiving the outer tubular wall assembly substantially
concentrically therethrough to define a second auxiliary passage
bound between the auxiliary tubular wall and the outer tubular wall
assembly.
[0089] The heat rejection fluid and the heat reclaiming fluid of
said at least one heat reclaiming passage are then preferably
arranged such that: [0090] i) the heat rejection fluid is received
in one of the first and second auxiliary passages so as to be
arranged in heat exchanging relationship with the working fluid
through a corresponding one of the inner and outer tubular wall
assemblies; and [0091] ii) the heat reclaiming fluid is received in
another one of the first and second auxiliary passages different
than the heat rejection fluid so as to be arranged in heat
exchanging relationship with the working fluid through a
corresponding one of the inner and outer tubular wall assemblies
different than the heat rejection fluid.
[0092] When there is more than one heat reclaiming passage, each
receiving heat reclaiming fluid therein, preferably the heat
rejection fluid and the heat reclaiming fluid are each arranged in
heat exchanging relationship through respective different
boundaries of the working passage of the condenser. In this
instance, the condenser can include an outer tubular wall assembly
and a plurality of independent inner tubular wall assemblies
extending alongside one another longitudinally within the outer
tubular wall assembly. The working passage of the condenser is thus
defined as the volume within the outer tubular wall assembly not
occupied by the plurality of inner tubular wall assemblies. The
working passage is thus the space extending between the inner and
outer tubular wall assemblies and extending longitudinally with the
outer tubular wall assembly. The heat rejection fluid is thus in
heat exchanging relationship with the working fluid through the
outer tubular wall assembly, while one or more heat reclaiming
fluids are located in respective ones of the inner tubular wall
assemblies so as to be in heat exchanging relationship with the
working fluid through the respective inner tubular wall
assembly.
[0093] There may be provided a heat reclaiming circuit in
communication between said at least one heat reclaiming passage of
the condenser and a storage device, for example a tank for storing
a heat reclaiming fluid therein, or a direct usage device, for
example, swimming pools, hot tubs, and washers, or an indirect
usage device, for example a heat exchanger, for using the heat
reclaim fluid, which has been circulated through said at least one
heat reclaiming passage by the heat reclaiming circuit. Each heat
reclaiming passage may be associated with: i) a heat reclaiming
fluid mover which is arranged to induce a flow of the heat
reclaiming fluid through the heat reclaiming passage, ii) a reclaim
temperature sensor for determining a temperature of the heat
reclaiming fluid prior to entering the condenser, and iii) a
controller arranged to increase operation of the heat reclaiming
fluid mover in response to a temperature of the heat reclaiming
fluid sensed by the reclaim temperature sensor being below a
prescribed target temperature. Increasing operation of the heat
reclaiming fluid mover can involve turning it on if it is currently
not in operation, or simply increasing the operation thereof, for
example by increasing speed or increasing the modulation if using a
modulating control.
[0094] A condensing condition control device may also be provided
which is arranged to determine a condensing condition of the
working fluid so that the controller may be arranged to decrease
operation of the heat reclaiming fluid mover in response to the
condensing condition being below a prescribed lower limit.
Decreasing operation of the heat reclaiming fluid mover can involve
turning it off if it is currently in operation, or simply reducing
the operation thereof, for example by reducing speed or reducing
the modulation if using a modulating control.
[0095] The system may further include: i) a heat rejection fluid
mover associated with the heat rejection fluid and arranged to
induce a flow of the heat rejection fluid across a boundary of the
working passage of the condenser, ii) a condensing condition
control device arranged to sense a condensing condition of the
working fluid, and iii) a controller arranged to increase operation
of the heat rejection fluid mover in response to the condensing
condition being above a prescribed upper limit. In some instances
the prescribed upper limit is greater than a target condensing
condition corresponding to optimal cooling efficiency.
[0096] When there is provided a heat rejection fluid mover
associated with the heat rejection fluid and arranged to induce a
flow of the heat rejection fluid across a boundary of the working
passage of the condenser and a condensing condition control device
arranged to determine a condensing condition of the working fluid,
the controller may also be arranged to increase operation of the
heat rejection fluid mover in response to the condensing condition
being above a prescribed upper limit if a heating demand on the
heat reclaiming fluid of said at least one heat reclaiming passage
has been met.
[0097] According to another aspect of the present invention there
is provided a heat reclaiming method operable within a vapor
compression refrigeration circuit typically, but not exclusively,
described as containing:
[0098] i) an evaporator i.e. a heat exchanger in thermal connection
with a heat source fluid on one side and an evaporating working
fluid on the other side; the working fluid intake port of the
evaporator is connected, either directly or indirectly, with or
without devices or control to the discharge port of the expansion
device via tubing; the evaporator discharge port is connected,
either directly or indirectly, with or without devices or controls,
to the suction port of the compressive device via tubing;
[0099] ii) a compressive device: capable of raising the pressure,
with the associated increase in temperature of a gaseous working
fluid; the suction port connected either directly or indirectly,
with or without devices or controls, to the discharge port of the
evaporator via tubing; the discharge port connected either directly
or indirectly, with or without devices or controls, to the intake
port of the condenser via tubing;
[0100] iii) a condenser i.e. a heat exchanger in thermal contact
with a heat sink fluid on one side and condensing working fluid on
the other side; the working fluid intake port of the condenser is
connected, either directly or indirectly, with or without devices
or controls, to the discharge port of the compressive device via
tubing; the condenser discharge port is connected, either directly
or indirectly, with or without devices or controls, to the intake
port of the expansion device via tubing;
[0101] iv) an expansion device: a device capable of maintaining a
pressure differential between its two ports; the intake port
connected either directly or indirectly, with or without devices or
controls, to the discharge port of the condenser via tubing; the
discharge port connected either directly or indirectly, with or
without devices or controls, to the intake port of the evaporator
via tubing;
[0102] in which the heat reclaiming method comprises configuring a
single refrigeration vapor compression condenser with gas or liquid
as the primary heat sink heat transfer fluid, to operate as a
double wall multi heat sink condenser, with liquid secondary and
subsequent heat sink heat transfer fluid(s) as exampled in the
detailed descriptions.
[0103] The heat reclaiming method is capable of simultaneous
thermal connection with multiple heat sink heat transfer fluids,
capable of transferring energy to any one, any combination of, or
all of, the individual heat sink heat transfer fluids, via separate
heat transfer fluid path(s) within the same condenser structure as
exampled in the detailed descriptions.
[0104] The heat reclaiming method is also capable of maintaining a
fixed active working fluid charge, in a multi heat sink
refrigeration vapor compression system by the use of a multi heat
sink compound condenser, eliminating the need for separate
refrigeration storage devices and associated controls as exampled
in the detailed descriptions.
[0105] Various embodiments of the invention will now be described
in conjunction with the accompanying drawings in which:
BRIEF DESCRIPTION OF THE DRAWINGS
[0106] FIG. 1 is a schematic of a prior art vapor compression
refrigeration circuit;
[0107] FIG. 2 is a schematic of a prior art simplified series flow
multiple condenser vapor compression circuit operating as a
desuperheater to the condenser;
[0108] FIG. 3 is a schematic of a prior art simplified series flow
multiple condenser vapor compression circuit operating as condenser
to sub-cooler;
[0109] FIG. 4 is a prior art multiple condenser vapor compression
circuit schematic;
[0110] FIG. 5A is a front view of a prior art air cooled
condenser;
[0111] FIG. 5B is an end view of the condenser according to FIG.
5A;
[0112] FIG. 5C is a partly sectional front view of one channel of
the condenser according to FIG. 5A;
[0113] FIG. 5D is an end view of the channel of FIG. 5C;
[0114] FIG. 6A is a partly sectional front view of an air cooled
condenser with a double wall heat reclaim;
[0115] FIG. 6B is an end view of the condenser according to FIG.
6A;
[0116] FIG. 6C is a partly sectional front view of one channel of
the condenser according to FIG. 6A;
[0117] FIG. 6D is an end view of the channel of FIG. 6C;
[0118] FIG. 7A is a partly sectional front view of an air cooled
condenser with a single wall heat reclaim;
[0119] FIG. 7B is an end view of the condenser according to FIG.
7A;
[0120] FIG. 7C is a partly sectional front view of one channel of
the condenser according to FIG. 7A;
[0121] FIG. 7D is an end view of the channel of FIG. 7C;
[0122] FIG. 8A is a partly sectional front view of an air cooled
condenser with multiple heat reclaims;
[0123] FIG. 8B is an end view of the condenser according to FIG.
8A;
[0124] FIG. 8C is a partly sectional front view of one channel of
the condenser according to FIG. 8A;
[0125] FIG. 8D is an end view of the channel of FIG. 8C;
[0126] FIG. 9A is a partly sectional front view of a prior art tube
in tube coaxial liquid-cooled condenser with heat rejection
[0127] FIG. 9B is a partly sectional front view of a section of the
condenser according to FIG. 9A;
[0128] FIG. 9C is an end view of the condenser section of FIG.
9B;
[0129] FIG. 10A is a partly sectional front view of a tube in tube
in tube coaxial liquid-cooled condenser with central heat rejection
at the inner side of the working passage and double wall heat
reclaim at the outer side of the working passage;
[0130] FIG. 10B is a partly sectional front view of a section of
the condenser according to FIG. 10A;
[0131] FIG. 10C is an end view of the condenser section of FIG.
10B;
[0132] FIG. 11A is a partly sectional front view of a tube in tube
in tube coaxial liquid-cooled condenser with central double wall
heat reclaim at an inner side of the working passage and heat
rejection at the outer side of the working passage;
[0133] FIG. 11B is a partly sectional front view of a section of
the condenser according to FIG. 11A;
[0134] FIG. 11C is an end view of the condenser section of FIG.
11B;
[0135] FIG. 12 is a schematic representation of the condenser in
the heat rejection mode.
[0136] FIG. 13 is a schematic representation of the condenser in
the heat reclaiming mode.
[0137] FIG. 14 is a schematic representation of the condenser in
the combined heat rejection and heat reclaiming mode.
[0138] FIG. 15 is a schematic representation of a preferred
embodiment of the heat reclaiming refrigeration system.
[0139] FIG. 16 is a partly sectional front view of a section of the
condenser according to the system of FIG. 15, illustrating a
portion of the working passage.
[0140] FIG. 17 is an exemplary compressor performance chart,
and
[0141] FIG. 18 is an exemplary chart of comparative combined system
performance of a cooling system with electric water heating.
[0142] In the drawings like characters of reference indicate
corresponding parts in the different figures.
DETAILED DESCRIPTION
[0143] The multi heat sink compound condenser invention can be
applied to any vapor compression condenser, including but not
limited to: tube in shell; tube in tube; and, tube in fin. The
pertinent design consideration is that the condensing working
fluid, commonly a refrigerant, is in a simultaneous heat exchange
relationship with all of the multiple heat sink fluid heat transfer
passages.
[0144] It is acknowledged that changes to existing condenser
designs will be required to apply the invention.
[0145] Following are exemplary embodiments of some common condenser
designs as well as those same condenser configurations with
possible applications of the invention. These examples are to
illustrate the process and or method of application and are in no
way exhaustive of all of the refrigeration condenser designs in
which the invention can be applied, or all of the manners in which
it can be applied by a person skilled in the art.
[0146] Referring to the accompanying figures there is illustrated a
heat reclaiming refrigeration system generally indicated by
reference numeral 10 in FIG. 15. The system 10 circulates a working
fluid, therein through the various stages of a refrigeration
cycle.
[0147] As best shown in FIG. 15, the refrigeration system 10
generally includes a compressor device 12 which includes a
compressor inlet 14 and a compressor outlet 16 through which the
working fluid is received. The compressor device 12 is arranged to
compress the working fluid by raising the pressure, and hence also
the temperature, of the fluid from the inlet 14 to the outlet
16
[0148] The system 10 also includes a compound condenser 18 which
includes a working passage extending therethrough from a condenser
inlet 20 to a condenser outlet 22. Various embodiments of the
compound condenser 18 are shown in the accompanying figures as
described below.
[0149] In each instance, the condenser inlet 20 is in communication
with the compressor outlet 16 so as to be arranged to receive the
working fluid therefrom by using various forms of tubing or the
like by direct or indirect connection therebetween. The working
fluid passes through the working passage of the condenser 18 such
that it is in heat exchanging relationship with various heat sink
fluids to be described in further detail below to remove heat from
the working fluid and condense the working fluid between the
condenser inlet 20 and condenser outlet 22.
[0150] The system 10 further generally includes an expansion device
24 having a passage therethrough from an expansion device inlet 26
to an expansion device outlet 28 for receiving the working fluid
therethrough. The expansion device inlet is in communication with
the condenser outlet 22 so as to be arranged to receive the working
fluid therefrom by tubing or the like by direct or indirect
connection therebetween.
[0151] An evaporator device 30 includes a working passage extending
therethrough from an evaporator inlet 32 to an evaporator outlet
34. The evaporator inlet is in communication with the outlet of the
expansion device so as to receive the working fluid therefrom by
tubing or the like in direct or indirect connection therebetween.
The evaporator outlet is in communication with the compressor inlet
to complete the refrigeration cycle such that the compressor inlet
is arranged to receive the working fluid from the evaporator outlet
by tubing or the like in direct or indirect communication
therebetween. The working fluid in the working passage of the
evaporator device is arranged to be in heat exchanging relationship
with a target fluid to be cooled by the system by permitting heat
to be transferred from the target fluid to the working fluid in the
working passage of the evaporator device. In a typical example, in
a room which is to be cooled, the target fluid is air, which is
blown across the working passage of the evaporator.
[0152] Throughout the various embodiments, the working passage of
the condenser 18 is a constant volume passage receiving the working
fluid constantly therethrough so that the system maintains a fixed
active charge of working fluid throughout operation in the various
modes which include the heat reclaiming mode, the heat rejection
mode, or the combined heat rejection and heat reclaiming mode
described in further detail below. The fixed active charge of
working fluid is maintained regardless of the ratio of heat
transfer to the heat rejection fluid and heat transfer to the heat
reclaiming fluid in the combined heat rejection and heat reclaiming
mode.
[0153] In some embodiments, as represented schematically in FIG.
15, the working passage may comprise a single channel or multiple
channels 33 joined by inlet and outlet manifolds 35 which
collectively define a passageway from the condenser inlet 20 to the
condenser outlet 22 which is unchanging in volume and
configuration.
[0154] Generally at least a first portion of boundary walls of a
working passage of the condenser 18 is in heat exchanging
relationship with a heat rejection fluid. In the embodiments of
FIGS. 6A, 7A and 8A described below, the heat rejection fluid may
be ambient air or any other fluid surrounding the first portion of
the boundary walls which surround the working passage of the
condenser 18, that is the heat rejection fluid surrounds the
outermost boundary of the working passage in communication with
heat transfer fins or the like. Alternatively, as shown in the
embodiments of FIGS. 10A and 11A described below, the heat
rejection fluid may be contained within a respective heat rejection
passage which shares a boundary with the working passage for
transferring heat therebetween at the common boundary. The common
boundary between the working fluid and the heat rejection fluid is
preferably a single wall boundary, but may also take the form of a
double wall boundary in further embodiments.
[0155] In all instances, at least a second portion of the boundary
walls of the working passage of the condenser 18 is also arranged
in heat exchanging relationship with one or more heat reclaiming
fluids, within respective heat reclaiming passage(s) extending
through the condenser 18. The heat reclaiming passage(s) also share
a common boundary with the working passage in the condenser 18 for
exchanging heat between the working fluid and the heat reclaiming
fluid through the common boundary therebetween. The common boundary
between the working fluid and the heat reclaiming fluid may be a
single wall or double wall boundary as described below.
[0156] The first and second portions of the boundary walls of the
working passage of the condenser 18 through which heat is exchanged
with the heat rejection fluid and the one or more heat reclaiming
fluid(s) may each extend along a full length of a common section of
the working passage between the condenser inlet 20 and condenser
outlet 22. In this manner the working fluid through the condenser
18 is in simultaneous and concurrent heat exchanging relationship
with both the heat reclaiming fluid or fluids in the one or more
heat reclaiming passages and the heat rejection fluid along a full
length of the working passage through the condenser. In this
instance the one or more heat reclaiming passages extend in heat
exchanging relationship along the working passage from a heat
reclaim inlet in proximity to the condenser outlet 22 to a heat
reclaim outlet in proximity to the condenser inlet 20.
[0157] Alternatively, the common section of the working passage
which is in concurrent heat exchanging relationship with both the
heat rejection fluid and the one or more heat reclaiming fluids may
extend along only a portion of the length of the working passage.
In this instance one or more auxiliary sections of the working
passage in series with the common section is in heating
relationship with only one of the heat rejection fluid and the heat
reclaiming fluid of said at least one heat reclaiming passage. For
example, one auxiliary section of the working passage immediately
adjacent the condenser inlet may be in heat exchanging relationship
with only the heat reclaiming fluid corresponding to a
desuperheating zone of the condenser.
[0158] The heat reclaiming fluid in the heat reclaiming passage of
the condenser 18 is typically part of a heat reclaiming circuit 36
which cycles the fluid in a loop between the passage in the
condenser 18 and a storage, heat exchange, or use device 38. A heat
reclaim fluid mover 40 is provided in series with the circuit 36 in
the form of a pump for example for pumping the heat reclaiming
fluid when the fluid is water.
[0159] The circuit is typically also provided with an outlet
reclaim temperature control device 42 in series between the heat
reclaim fluid exiting the condenser 18 and entering the storage,
heat exchange, or use device 38 for measuring the temperature of
the heat reclaiming fluid exiting the condenser 18. Similarly an
inlet reclaim temperature control device 44 can be connected in
series between the fluid exiting the storage, heat exchange, or use
device(s) and the heat reclaim fluid entering the condenser 18 to
monitor the temperature of the heat reclaim fluid entering the
condenser 18.
[0160] In typical operation, the fluid mover 40 is activated to
circulate fluid through the heat reclaiming circuit until the
heating demands on the heat reclaiming fluid have been met. This
can be accomplished simply by providing a controller which actuates
the pump if the sensed temperature of the reclaim fluid at
temperature control device 44 falls below a target temperature for
the storage, heat exchange, or use device 38 which is determined to
satisfy heating requirements.
[0161] If the heat reclaiming circuit is combined with a plurality
of usage devices, each usage device can include its own heat
exchanging circuit in heat exchanging relationship with common or
separate storage, heat exchange, or use device(s). A respective
controller then controls the circulation of fluid through the
respective heat exchanging circuits to meet the respective heat
demand of the respective device(s).
[0162] The operation of the fluid mover 40 within the heat
reclaiming circuit affects the heat transfer to the heat reclaiming
fluid passing through the condenser 18 by actively introducing new
heat reclaiming fluid for heat exchanging with the working fluid.
Similarly the system 10 typically includes a fluid mover 46
associated with the heat rejection fluid(s) to control the flow of
heat rejection fluid across respective boundaries of the working
passage of the condenser 18 to affect the heat transfer rate to the
heat rejection fluid.
[0163] In the embodiments of FIGS. 6A, 7A, and 8A the heat
rejection fluid mover 46 is a fan which induces a flow of ambient
air across the outermost boundary of the working passage of the
condenser 18 when actuated to increase the transfer of heat from
the working fluid to the heat rejection fluid.
[0164] The working passage through the condenser 18 is typically in
the form of a passage defined between an outer tubular wall
assembly 48 which typically defines an outermost boundary of the
working passage and one or more inner tubular wall assemblies 50
typically defining an innermost boundary of the working
passage.
[0165] The inner tubular wall assembly 50 also typically defines a
respective first auxiliary passage therethrough for receiving a
heat reclaim fluid P3 or heat rejection fluid P1 therethrough
depending on the application. In all instances, typically one of a
heat reclaim fluid or a heat rejection fluid is communicated
through the passage of the inner tubular wall assembly 50 to be in
heat exchanging relationship across the innermost boundary of the
working passage defined by the inner tubular wall assembly while a
different one of the heat reclaim or heat rejection fluids is in
heat exchanging relationship with outer tubular wall assembly 48
defining the outermost boundary wall of the working passage through
the condenser 18.
[0166] The fluid in heat exchanging relationship across the
outermost boundary wall of the working passage may be contained
within an auxiliary boundary wall 62 as in the embodiments of FIGS.
10A and 11A for example. In this instance the space between the
outer tubular wall assembly 48 and the auxiliary boundary wall 62
defines a second auxiliary passage in addition to the first
auxiliary passage bound by the inner tubular wall assembly 50.
[0167] In some of the embodiments of the condenser 18, for example
as shown in FIGS. 6A, 10A and 11A, when the heat reclaiming fluid
is hot water, for example potable water or water for various
domestic usages or any non-domestic application, such that it is
important to prevent contamination of the water by the working
fluid, or the working fluid by the water, due to a leak, one of the
tubular wall assemblies 48 or 50 which is between the working fluid
P2 and the heat reclaiming fluid P3 comprises a double wall
assembly.
[0168] The double wall assembly is formed of a first tubular wall
60A and a second tubular wall 60B received concentrically and
longitudinally within the first tubular wall 60A so as to define an
annular gap therebetween. Tubular wall 60B and 60A are largely in
tight heat conductive contact, forming a minimal gap between them.
The gap between them is externally vented, generally open to the
atmosphere, allowing the fluid from a breach of either 60B or 60A
to escape and not contaminate the other.
[0169] To assist in operation of the overall system 10 of FIG. 15
which incorporates any one of the embodiments of the condenser 18
therein, the controller of the system also communicates with an
inlet condenser control device 52 connected in series with the
tubing carrying the working fluid from the compressor device to the
condenser 18 and an outlet condenser control device 54 in series
with the tubing carrying the working fluid from the outlet of the
condenser 18 to the inlet of the expansion device.
[0170] In the simplest form of operation of the system, the heat
reclaim fluid mover 40 that moves the heat reclaim fluid will run
at the same time as the compressor 12 that moves the working fluid.
There would be a control device somewhere in the system between the
compressor and the expansion device, reacting to operating
conditions, which would directly, or indirectly through a system
control, cause the heat rejection fluid mover to be activated in
response to predetermined conditions. Depending on the application,
additional controls can be added to deal with too cold and or too
hot heat reclaim temperatures, and to improve performance.
[0171] The condenser inlet control device 52 is preferably a
pressure and temperature sensor for determining the real
temperature and the condensing pressure from which the condensing
temperature can then be determined. In alternative embodiments, the
control device 52 may comprise either a pressure or temperature
sensor for directly measuring the temperature or pressure of the
working fluid at the condenser inlet 20.
[0172] Operational strategies roughly in order of simplicity with
simplest first are as follows:
[0173] 1) A heat reclaim fluid mover 40 that starts at the same
time as compressor 12 for heat reclaim, and the heat rejection
fluid mover 46 starting for heat rejection based on high condensing
pressure which is measured at control device 52.
[0174] 2) The same system as 1 with an additional sensor device 44
that monitors the heat reclaim fluid temperature and limits on/off
of the heat reclaim fluid mover(s) 40 to prevent over heating of
the heat reclaim fluid.
[0175] 3) The same system as 1 or 2 with control device 52 being
used additionally, to cause the system control to limit the heat
reclaim fluid mover 40 operation, to control against too low
condensing conditions.
[0176] 4) The same system as 1 or 2 or 3 with an additional control
device to the heat rejection fluid mover(s) and or heat reclaim
fluid mover(s) to adjust operating pressures based on multiple
parameters to maximize efficiency.
[0177] Referring generally to the various embodiments of the
condenser, the operation of the heat reclaiming refrigeration
system 10 of the present invention, as depicted on FIG. 15, and
more particularly the compound condenser 18, will now be described
in reference to FIGS. 12 through 15.
[0178] The compressor 12 is started when there is a demand for
cooling. Working fluid in the evaporator 30 is evaporated absorbing
heat. The absorption of this heat causes the target fluid in
contact with the evaporator to be cooled providing the desired
cooling. The compressor 12 compresses the gaseous working fluid
coming from the evaporator raising the working fluid's pressure and
associated temperature. The working fluid exits the compressor 12
and enters the heat-reclaim condenser 18 following the working
fluid path P2. Heat can be transferred from the hot working fluid
through the inner wall to the heat-reclaim fluid in P3 or through
the outer wall to the heat-rejection fluid in P1. The amount of
heat that is transferred to each of the paths is governed by the
difference in temperature between the hot working fluid in P2 and
each of the other fluids, heat-reclaim in P3 and heat-rejection in
P1.
[0179] In order to maximize heat transfer to the heat-reclaim fluid
the system must be operated in a manner that maximizes the
difference in temperature between the hot working fluid in P2 and
the reclaim fluid in P3 and minimizes the difference between the
hot working fluid in P2 and the heat-rejection fluid in P1. In
order to do this the heat rejection fluid mover 46 can be kept
switched off, allowing the heat-rejection fluid in P1 to warm up
close to the working fluid temperature in P2 and heat reclaim fluid
mover 40 can be operated to move the heat reclaim fluid through P3
to a storage, heat exchange, or use device(s) 38 and replenishing
through P3 with colder heat-reclaim fluid from the device(s).
38
[0180] As long as there is a demand for cooling, the system can
operate in this manner transferring most of the heat to the
heat-reclaim fluid. In fact with an unlimited supply of cool
heat-reclaim fluid no heat-rejection would be required.
[0181] The process however, is not unlimited and most heat-reclaim
applications do not have unlimited amounts of heat reclaim demand.
Refrigeration compressors have operating limits and as the
heat-reclaim fluid temperature rises the compressor compression
ratio must rise as well in order to maintain the difference in
temperature between P2 and P3.
[0182] As can be seen in FIG. 17, in a typical compressor
performance chart, there are absolute barriers to operation, based
on the needed cooling temperature, with lower needed cooling
temperatures resulting in lower possible condensing temperatures.
In addition, as the needed condensing temperature rises, for a
given cooling evaporation temperature, both the compressor capacity
and efficiency are reduced.
[0183] Example 1 and 2 on FIG. 17 demonstrate this. Example 1 is
the maximum condensing temperature, 140 F, for this compressor
operating with a 30 F evaporating temperature, whereas Example 2 is
at a lower condensing temperature, 110 F, for the same evaporating
temperature. The effect of the lower condensing temperature is an
increase in cooling capacity of nearly 34% and an increase in the
cooling EER (Energy Efficiency Ratio) of over 100%.
[0184] In order for this compressor to remain within its
recommended operating range for a 30 F evaporating temperature, the
condensing temperature must be kept below 140 F, and the lower the
condensing temperature can be kept the higher the cooling
efficiency will be.
[0185] As long as the heat-reclaim fluid is at a temperature that
maintains the refrigeration system condensing temperature below
design, the heat rejection fluid mover 46 remains off.
[0186] When the discharge pressure and or temperature at the
control device 52 exceeds the design limits, the heat-rejection
fluid mover 46 is started, and operated in such a manner that the
condensing temperature of the working fluid circuit is kept at the
desired design temperature. This may be done by cycling the heat
rejection fluid mover 46 off and on, or preferably, controlling the
speed of the heat rejection fluid mover 46.
[0187] The effect of the heat rejection fluid mover(s) operating is
to increase the difference in temperature between P2 and P1, and to
increase the associated heat transfer from P2 to P1. The combined
heat transfer of P2 to P3 and P2 to P1 is now capable of
maintaining the design condensing temperature, when the heat
transfer from P2 to P3 only, was not. The result is that cooling
operation and efficiency can be maintained, and heat-reclaim can be
maximized for the conditions.
[0188] As the temperature of the heat-reclaim fluid in P3 continues
to rise, the heat transfer from P2 to P3 will continue to decrease,
resulting in the need for the heat transfer from P2 to P1 to
increase. This will occur automatically as the discharge control
device 52 reacts to the higher compressor discharge pressures and
or temperatures by causing the system control to increase the speed
or operational frequency of the heat rejection fluid mover 46.
[0189] The heat-reclaim fluid passing through P3 can be at any flow
rate desired as long as the temperature of the heat-reclaim fluid
as measured at temperature control device 44 entering the condenser
18 is, preferably, at or below the temperature of the leaving
liquid working fluid as measured by the temperature control device
54. Cooling efficiency and ultimately the amount of energy that can
be transferred is enhanced by greater flow of the heat reclaim
fluid.
[0190] It is possible to have operating conditions where the
heat-reclaim temperature 44 may be higher than the liquid working
fluid temperature 54 in that case the heat-reclaim fluid flow rate
must be controlled so as to ensure that the temperature of the
heat-reclaim fluid leaving the condenser 18 as measured at
temperature sensor 42 is higher than the entering temperature 44.
This is done by varying the capacity of the heat-reclaim fluid
mover 40 or alternatively by the use of a modulating valve in the
water line. If this is not done there is a possibility that at
these conditions the heat-reclaim fluid could actually be cooled by
the working fluid.
[0191] If storage, heat exchange, or use device 38 reaches the
desired maximum temperature as measured by temperature control
device 44, heat reclaim fluid mover 40 can be shut off to prevent
further heat-reclaim heat transfer. Although the system will
automatically adapt to the changing condensing conditions, and
maintain the working fluid condensing temperature by modulating the
heat rejection fluid mover 46, if there is no need for
heat-reclaim, optimally, the operating condensing temperature can
be lowered to improve cooling efficiency.
[0192] For the purpose of this document the term "Total output
power" will be defined as the result of a useful energy transfer,
specifically, cooling for air conditioning and the heating of a
fluid, expressed in Watts.
[0193] The efficiency of a refrigeration system operating in
cooling is typically measured in EER, which is defined as
BTU/Watt-hr. When the same system is used for heating, the
efficiency is measured in COP, which is Watts/Watts, or
Watt-hr/Watt-hr, or BTU/BTU. As can be seen they are basically the
same formula. The only difference is that the EER will be higher by
the ratio of a watt-hr to BTU which is 3.412. In both cases the
numerator is the work done (energy output) and the denominator is
the energy required to do it (energy input).
[0194] As discussed previously, cooling efficiency goes down as
condensing temperature goes up. However, the ultimate maximum
temperature of the heat-reclaim fluid, for a given heat exchanger
design, goes up as the condensing temperature goes up. A higher
potential refrigeration condensing temperature not only improves
the potential usefulness of the heat-reclaim fluid but can also
increase the amount of energy that may be transferred. Fortunately
because of the beneficial effect of the heat-reclaim, although
cooling efficiency may go down with higher condensing temperatures,
total system efficiency, the combination of cooling and
heat-reclaim divided by the energy used, will actually remain very
high, and higher than cooling efficiency alone at lower condensing
temperatures.
[0195] The following examples are demonstrative of the concept and
are in no way prescriptive as to operation:
Operation 1 (Example 2 from FIG. 17 {cooling only}) Cooling
watts=BTUH/3.412=15000/3.412=4396 watts Input Power=1340 watts
Cooling COP=4396/1340=3.28
[0196] Heat of rejection=cooling Watts+input power=4396+1340=5736
Watts Operation 2 (Example 2 from FIG. 17 {cooling and
heat-reclaim}) Cooling watts=BTUH/3.412=15000/3.412=4396 watts Hot
water production=heat of rejection=4396+1340=5736 watts Total
output power=cooling+hot water production=4396+5736=10132 watts
Total system COP=Total output power/power input=10132/1340=7.56
Operation 3 (Example 1 from FIG. 17 {cooling and heat-reclaim})
FIG. 18 Line 8 Cooling watts=BTUH/3.412=11200/3.412=3282 watts
Cooling COP=3282/2130=1.54
[0197] Heat of rejection=cooling Watts+input power=3282+2130=5412
watts Hot water production=heat of rejection=5412 watts Total
output power=cooling+hot water production=3282+5412=8694 watts
COP=Total output power/power input=8694/2130=4.08
[0198] Although the cooling efficiency COP in Operation 3 at 1.54
is less than 1/2 the COP cooling efficiency of Operation 1 at 3.28,
the overall total system efficiency, because of the value of the
heat-reclaim, is the ratio of 4.08/3.28=24% higher, demonstrating
the benefit of operating at higher condensing temperatures if it
increases the heat-reclaim energy. Operation 1 is a cooling only
COP and has no heating component through heat-reclaim or the use of
primary energy.
[0199] To get a truer system comparison of operating efficiency,
both compared systems must produce the same amount of cooling and
water heating, therefore consideration of the energy to heat the
hot water in an alternative manner is required. Therefore the
cooling only system could be described as a standard cooling system
with electric water heating equivalent to the heat-reclaim.
Operation 4 (comparative standard system providing the same cooling
and hot water production as Operation 3. with the same cooling
efficiency as Example 2. FIG. 17, and standard electric hot water
production--FIG. 18 Line 16.) Cooling
watts=BTUH/3.412=11200/3.412=3283 watts Power=1001 watts
Cooling COP=3283/1001=3.28
[0200] 5413 watts of hot water Power for hot water=5413 Total Input
power=Input Power of the refrigeration system+Power for hot
water=1001+5413=6414 Watts Total output power=cooling+hot water
production=3283+5413=8695 watts Total system COP using electric
heat for hot water=Total output power/power
input=8695/6414=1.36
[0201] When the additional energy required to heat the hot water is
added to the input energy of the standard air conditioning system
operating at the lower condensing conditions of Example 2, FIG. 17.
as shown in Operation 4, the resultant total system COP is only
1.36.
Even though the cooling COP of the standard system at 3.28 Example
2. FIG. 17. is over 100% greater than the cooling COP of the heat
reclaim system of 1.54, operating at the higher condensing
conditions of Example 1. FIG. 17, this efficiency advantage is not
enough to overcome the less energy efficient production of hot
water. The heat reclaim system has a combined, cooling and water
heating, efficiency COP of 4.08 FIG. 18 Line 8, and the standard
cooling system, providing the same cooling and hot water, has a
combined efficiency COP of 1.36 FIG. 18 Line 16. The result is that
the standard non heat reclaim system will use three times as much
energy, 4.08/1.36=3, than the heat reclaim system, to provide the
same amount of cooling and hot water.
[0202] An operational matrix can be developed for each application
to establish the best compromise for condensing temperature
operation. It may share characteristics with an exemplary
comparative combined system performance chart of a cooling system
with electric water heating as shown in FIG. 18. Although, as can
be clearly seen, even when as little as 50% of the available heat
is recovered, to heat the hot water, the combined efficiency of the
heat reclaim system will be over twice as high as the standard
system, without heat reclaim, and using electric hot water
heat.
When there is a demand for cooling and no demand for heat reclaim,
the system operates in the heat rejection mode of FIG. 12. In this
instance: the refrigeration compressor 12 is operating, heat
reclaim fluid mover 40 is off, heat rejection fluid mover 46 is
active, and the system operates as a standard refrigeration system
with 100% of condenser heat being rejected. In the heat rejection
mode a system control is arranged to maintain the heat reclaiming
fluid in a passive and non-flowing condition in heat exchanging
relationship with the working passage of the condenser 18 while
also maintaining the heat rejection fluid in an active and flowing
condition in heat exchanging relationship with the working passage
of the condenser 18.
[0203] When there is a demand for cooling and sufficient heat
reclaim demand for full heat reclaim condensing, the system
operates in the full heat reclaiming mode of FIG. 13. In this
instance: refrigeration compressor 12 is operating; heat reclaim
fluid mover 40 is active; the heat rejection fluid mover 46 is off,
and the system operates as 100% heat-reclaim unit. In the full heat
reclaim mode a system control device is arranged to maintain the
heat reclaiming fluid in an active and flowing condition in heat
exchanging relationship with the working passage of the condenser
18, while maintaining the heat rejection fluid in a passive and
non-flowing condition in heat exchanging relationship with the
working passage of the condenser 18.
[0204] Alternatively when there is a demand for cooling and there
is not enough heat reclaim demand for full heat reclaim the system
is operable for simultaneous heat reclaim and heat rejection at the
condenser 18, as depicted in FIG. 14. In this instance:
refrigeration compressor 12 is operating; heat reclaim fluid mover
40 is active; the heat rejection fluid mover 46 is also active. In
the combined heat rejection and heat reclaiming mode the controller
of the system is arranged to maintain the heat reclaiming fluid in
an active and flowing condition in heat exchanging relationship
with the working passage of the condenser 18, and maintain the heat
rejection fluid in an active and flowing condition in heat
exchanging relationship with the working passage of the condenser
18. Ideally a control device is used to modulate the heat rejection
fluid mover 46 to maintain the compressor condensing conditions as
measured at condenser inlet control device 52, and condenser outlet
control 54, at the desired operating temperatures and pressures
while maximizing heat reclaim.
[0205] Higher condensing pressures will typically result in less
efficient operation of the refrigeration circuit, which is a
negative, and higher reclaim water temperatures, which is a
positive. Depending on application and energy costs these operating
parameters can be changed to optimize the system performance.
Typically this is accomplished by modulating the heat reclaim fluid
mover 40 and heat rejection fluid mover 46 to maintain a condensing
condition measured at control device 52.
[0206] Refrigeration systems also typically operate more
efficiently with lower condensing temperatures. As the temperature
of the reclaim water rises the condensing temperature must rise to
maintain the heat transfer which is governed by the difference in
temperature between the working fluid and the temperature of the
heat reclaim fluid in the condenser.
[0207] At some point the required condensing temperature for
transferring all of the heat to the heat-reclaim fluid becomes
undesirable or impossible for any of a number of reasons including
but not limited to: Lower system capacity; Lower system efficiency;
or, System design limits. When full heat transfer to the
heat-reclaim fluid is no longer desired or possible some of the
heat can still be transferred to the heat-reclaim fluid by
operating the condensing circuit in such a manner as to maintain
condensing temperatures as high as possible, within the system
limitations, based on the net benefit of the reclaimed heat or
desired operating conditions. At these conditions all of the
compressor superheat and some of the condensing energy can still be
transferred to the heat-reclaim fluid.
[0208] In the heat reclaiming mode of FIG. 13, the controller is
preferably arranged to start the heat reclaiming fluid mover 40 in
response to the temperature of the heat reclaiming fluid sensed by
the control device 44, being below a prescribed target temperature.
The system control is further arranged to decrease or limit
operation of the heat reclaiming fluid mover 40 in response to the
condensing pressure being below a prescribed lower operational
limit or in response to the working fluid condensing conditions
being too low, as measured by control device 52. The controller
will switch from the heat reclaiming mode to the combined mode by
actuating the heat rejecting fluid mover 46 in response to the
condensing pressure or temperature condition sensed by the
condensing condition control device 52 being above a prescribed
upper limit. The prescribed upper limit may be greater than a
target condensing temperature or pressure corresponding to optimal
cooling efficiency in consideration of heat recovery to increase
overall efficiency.
[0209] In the heat rejection mode of FIG. 12, the system control is
preferably arranged to actuate or increase operation of the heat
rejection fluid mover 46 in response to a condensing pressure
sensed by the sensor device 52 being above a prescribed upper
limit, if a heat reclaim demand on the heat reclaiming fluid of
said at least one heat reclaiming passage has been met.
[0210] Particulars with regard to various embodiments of the
compound condenser 18 will now be described in the following
pages.
[0211] For comparison purposes, FIGS. 5A through 5D show a prior
art air-cooled condenser 200 in which heat transfer fins 202
transfer heat to the heat-rejection heat sink gaseous heat transfer
fluid, typically air, from the tubing 204 constraining the gaseous
compression working fluid. The tubing 204 has an outer tube wall
constraining the gaseous working fluid therein. In this instance, a
standard air-cooled condenser creates two fluid paths, the first
being the gas that travels over the fins external to the tube, P1,
and a second within the inner tube which constrains the gaseous
working fluid in P2. The path constraining the gaseous working
fluid will be in fluid connection with the compressive device and
expansion device as described previously. Heat is transferred
across the wall of the tube from the condensing gaseous working
fluid into the fins and then into the gaseous heat rejection heat
transfer fluid. The gaseous working fluid enters the condenser as a
superheated gas. While passing through the condenser the working
fluid will first cool sensibly to the saturation point then with no
change in temperature it will then condense to a liquid giving off
the latent heat. When fully condensed additional sensible cooling
will occur and the working fluid will then leave the condenser as a
subcooled liquid.
[0212] FIGS. 6A through 6D illustrate one embodiment of the
condenser 18 according to the present invention in which an
air-cooled condenser according to FIGS. 5A through 5D has been
enhanced so that the working fluid in passage P2 is in concurrent
heat exchanging relation with i) the heat reclaiming fluid in
passage P3 and ii) the heat rejection fluid in P1 using the heat
transfer fins 202. More particularly the condenser 18 in this
instance is a heat recovery, dual sink, air/water-cooled compound
condenser. The heat transfer fins 202 transfer heat to the heat
rejection heat sink gaseous heat transfer fluid, typically air. The
outer tubular wall assembly 48 mounts the fins 202 thereon and
defines the outer boundary constraining the gaseous working fluid
in P2. The outer tubular wall assembly 48 receives the inner
tubular wall assembly 50 concentrically therein to extend
longitudinally within the outer tubular wall assembly 48. The inner
tubular wall assembly 50 constrains the heat-reclaim liquid heat
transfer fluid therein.
[0213] In this embodiment, the inner tubular wall assembly 50
defines the double wall assembly comprised of the first tubular
wall 60A and the second tubular wall 60B, as previously described.
The double wall assembly comprised of the first and second tubular
walls thus collectively acts as the barrier or boundary between the
working fluid in P2 and the heat reclaim liquid in P3. The first
tubular wall 60A of the inner tubular wall assembly 50 defines the
inner boundary of the working passage in this instance. The annular
gap P4 between the first and second tubular walls 60A and 60B again
defines a safety passage, which should be externally vented.
[0214] The compound multi-tube in fin condenser 18 shown in FIGS.
6A to 6D thus creates three fluid paths, one is the gas in P1 that
travels over the fins external to the tube, a second is the heat
reclaim fluid passage P3, and a third is the working fluid passage
P2. The safety passage P4 prevents the cross-contamination of the
heat-recovery heat transfer fluid and the working fluid in the
event of a failure of a tube wall.
[0215] The working fluid is constrained in P2. P3 constrains a
heat-recovery liquid heat sink heat transfer fluid, and in P1 is
the gaseous heat-rejection heat sink heat transfer fluid external
to the outer tube in contact with the fin.
[0216] P2 constraining the working fluid will be in fluid
connection with the refrigeration system compressor device and
expansion device as described previously.
[0217] There are three possible modes of heat transfer operation
within the compound condenser 18 according to FIGS. 6A through 6D
as follows.
[0218] i) Heat from the gaseous working fluid is transferred
through the double wall, inner tubular wall assembly 50 at the
inner boundary of P2 to the heat-recovery heat transfer fluid in
P3. Little or no heat is transferred from the gaseous working fluid
in P2 through the heat transfer fin to P1. This is accomplished by
stopping the flow of the gaseous heat-rejection heat transfer fluid
through P1 while allowing the flow of the heat-recovery heat
transfer fluid through P3.
[0219] ii) Heat from the gaseous working fluid is transferred from
P2 through the outer tubular wall assembly 48 to the attached heat
transfer fins then to the gaseous heat-rejection heat sink heat
transfer fluid in P1. Little or no heat is transferred from the
gaseous working fluid in P2 through the inner tube wall assembly to
the heat-recovery heat transfer fluid P3. This is accomplished by
stopping the flow of the heat-recovery heat transfer fluid through
P3 while allowing the flow of the gaseous heat-rejection heat
transfer fluid through P1.
[0220] iii) Heat from the gaseous working fluid is transferred from
P2 through the inner tubular wall assembly 50 to the P3
heat-recovery heat transfer fluid; as well as from P2 through the
outer walls and fins to the P1 gaseous heat-rejection heat transfer
fluid simultaneously. This is accomplished by allowing the flow of
all of the heat transfer fluids. To control the amount of energy
being transferred to each of the individual heat transfer fluids,
the flows of the heat transfer fluids can be varied.
[0221] Regardless of the heat transfer mode, the gaseous working
fluid enters the condenser 18 as a superheated gas. While passing
through the condenser 18, the working fluid will first cool
sensibly to the saturation point then with no change in temperature
it will condense to a liquid giving off the latent heat. When fully
condensed, additional sensible cooling will occur and the working
fluid will then leave the condenser 18 as a subcooled liquid.
[0222] FIGS. 7A to 7D illustrate another embodiment of the
condenser 18 in which the condenser in this instance comprises a
compound air-cooled condenser using a single wall between the
working fluid and heat reclaim. Although the invention is
envisioned as a double wall arrangement as in FIGS. 6A to 6D to
protect both the vapor refrigeration circuit and the liquid
heat-reclaim heat sink circuit from cross contamination in the
event of a failure of a tube wall, the invention is equally
applicable to a single wall configuration of the inner tubular wall
assembly 50 in the event that the protection is not desired or
required.
[0223] The operation of the invention in single walled
configuration is identical to the operation as described in FIGS.
6A to 6D except that the inner tubular wall assembly 50 in this
instance comprises a single wall inner tube so that heat is
transferred from the gaseous working fluid in P2 through the single
wall inner tube to the heat-reclaim heat sink fluid in P3.
[0224] FIGS. 8A to 8D illustrate another embodiment of the
condenser 18 in which the condenser comprises a compound air-cooled
condenser using more than one heat reclaim. For purposes of
manufacturing and or application, the invention can be envisioned
with multiple heat recovery heat sink paths, shown with, but not
limited to two. If so equipped, this application of the invention
would operate in the same general manner as FIGS. 6A to 6D and 7A
to 7D if the fluids in all of the paths were connected to the same
heat-reclaim heat sink.
[0225] If the heat reclaim paths are connected to different
heat-reclaim heat sinks, then additionally the proportion of heat
being transferred to each of the heat-recovery heat sinks can be
modulated by adjusting the fluid flow to the appropriate paths.
[0226] More particularly, in the embodiment of FIGS. 8A through 8D,
there is provided more than one heat reclaiming passage P3 through
the condenser, receiving heat reclaiming fluid therein such that
the one or more heat reclaiming fluids are arranged in heat
exchanging relationship through respective different boundaries of
the working passage of the condenser.
[0227] The heat reclaiming passages are defined by respective
independent inner tubular wall assemblies 50 extending alongside
one another such that the overall grouping of inner tubular wall
assemblies 50 may be substantially concentrically received with the
outer tubular wall assembly 48. The outer tubular wall assembly 48
again defines the outer boundary of the working passage through the
condenser which receives the working fluid in P2. In this instance,
the working passage of the condenser includes both a peripheral
portion which surrounds the grouping of inner tubular wall
assemblies in a circumferential or annular direction adjacent the
outer boundary as well as a remaining inner portion between the
inner tubular wall assemblies 50. The working passage is thus the
volume or space between the outer tubular wall assembly 48 and the
collective grouping of inner tubular wall assemblies 50 which
define respective boundaries about the working fluid passage. The
heat rejection fluid is thus in heat exchanging relationship with
the working fluid through the outer tubular wall assembly 48, while
the one or more heat reclaiming fluids are located in respective
ones of the inner tubular wall assemblies 50 so as to be in heat
exchanging relationship with the working fluid through the
respective inner tubular wall assemblies.
[0228] In the illustrated embodiment of FIGS. 8A through 8D, the
inner tubular wall assemblies each comprise a single wall tube.
However, similarly to the difference between the embodiments of
FIGS. 6A through 6D and 7A through 7D, in a variation to the
embodiment of FIGS. 8A through 8D, each inner tubular wall assembly
50 may instead comprise a double wall assembly formed of a first
tubular wall 60A and a second tubular wall 60B with an annular
safety gap P4, there between across which heat can be
transferred.
[0229] Turning now to FIGS. 9A through 9C a prior art tube in tube
coaxial liquid-cooled condenser 300 is shown. In this instance the
condenser includes an outer tube wall 302 which concentrically
receives an inner tube wall 304 therein so that the annular space
constrained between the inner and outer tube walls defines a heat
rejection passage for a heat rejection fluid in P1. The inner tube
wall constrains the gaseous working fluid in P2 therein.
[0230] Alternatively, the fluids in P1 and in P2 can be readily
reversed. In either instance, the tube in tube condenser 300
creates two fluid paths, one between the outer tube and the inner
tube and a second within the inner tube. Either one of these paths
will constrain the gaseous working fluid with the other
constraining a heat-rejection liquid heat sink heat transfer
fluid.
[0231] The path constraining the gaseous working fluid will be in
fluid connection with the compressor device and expansion device as
described previously.
[0232] Heat is transferred across the wall of the inner tube from
the condensing gaseous working fluid to the heat sink heat transfer
fluid regardless of the path each has. The heat will transfer from
the inner tube path to the outer path if the working fluid is
constrained in the inner tube, and from the outer path into the
inner tube if the heat sink heat transfer fluid is constrained in
the inner tube.
[0233] The gaseous working fluid enters the condenser as a
superheated gas. While passing through the condenser the working
fluid will first cool sensibly to the saturation point then with no
change in temperature it will condense to a liquid giving off the
latent heat. When fully condensed additional sensible cooling will
occur and the working fluid will then leave the condenser as a
subcooled liquid.
[0234] Turning now to FIGS. 10A through 10C and FIGS. 11A through
11C, two further embodiments of the condenser 18 are shown in which
the condenser in both instances generally comprises a tube in tube
liquid-cooled condenser as in FIG. 9A which has been modified to
include an additional heat reclaim passage, thus creating a
compound tube in tube in tube condenser. More particularly, in
these embodiments of the invention, the working passage P2 of the
condenser comprises a generally annular passage defined between the
outer tubular wall assembly 48 at the outer side of the working
passage and the inner tubular wall assembly 50 at the inner side of
the working passage which extends substantially concentrically and
longitudinally within the outer tubular wall assembly.
[0235] The inner tubular wall assembly 50 defines a respective
first auxiliary passage bound by the inner tubular wall assembly 50
which receives a first one of the heat reclaim or rejection fluids
such that the first one of the heat reclaim or heat rejection
fluids is in heat exchanging relationship with the working fluid
across the inner tubular wall assembly 50.
[0236] The condenser 18 of FIGS. 10A to 10C and 11A to 11C differs
from the prior art configuration of FIGS. 9A through 9C in that it
further includes the auxiliary tubular wall 62 surrounding the
outer tubular wall assembly 48 of the working passage so that the
auxiliary tubular wall 62 receives the outer tubular wall assembly
48 substantially concentrically therein. The auxiliary tubular wall
62 and the outer tubular wall assembly 48 of the working passage P2
define a second auxiliary passage which is annular in shape between
the auxiliary tubular wall 62 and the outer tubular wall assembly
48 of the working passage.
[0237] The second auxiliary passage receives a second one of the
heat reclaim or heat rejection fluids different from the first one
of the fluids received in the first auxiliary passage noted above
such that the second one of the heat reclaim or heat rejection
fluids is in heat exchanging relationship with the working fluid
across the outer tubular wall assembly 48.
[0238] Regardless of which of the heat reclaim and heat rejection
fluids is received in the first auxiliary passage or the second
auxiliary passage, in each instance the heat rejection fluid and
the heat reclaiming fluid are received in the first and second
auxiliary passages so as to be arranged in heat exchanging
relationship with the working fluid at opposing inner or outer
sides of the working passage. More particularly, the heat rejection
fluid and the heat reclaiming fluid are arranged such that: i) the
heat rejection fluid is received in one of the first and second
auxiliary passages so as to be arranged in heat exchanging
relationship with the working fluid through a corresponding one of
the inner and outer tubular wall assemblies; and ii) the heat
reclaiming fluid is received in another one of the first and second
auxiliary passages different than the heat rejection fluid so as to
be arranged in heat exchanging relationship with the working fluid
through a corresponding one of the inner and outer tubular wall
assemblies different than the heat rejection fluid.
[0239] The compound tube in tube in tube condenser 18 again creates
three fluid paths, one between the outer auxiliary tube 62 and the
outer tubular wall assembly 48 at the outer side of the working
passage, a second between the outer tubular wall assembly 48 and
the inner tubular wall assembly 50 of the working passage to define
the working passage P2, and a third within the inner tubular wall
assembly 50 of the working passage. The gaseous working fluid is
constrained in P2. The other two paths, P1 and P3, constrain
separate heat sink heat transfer fluids.
[0240] In each of the embodiments of FIGS. 10A to 10C and 11A to
11C one of the outer tubular wall assembly 48 or the inner tubular
wall assembly 50 of the working passage which forms a common
boundary with the heat reclaim fluid comprises the double wall
assembly. As described above, the double wall assembly in each
instance includes a first tubular wall 60A and a second tubular
wall 60B which are generally concentric with one another and in
tight physical and heat conductive contact with each other so as to
allow heat exchange, but not so tight as to prevent the fluid from
a breach of either of the tubular walls from escaping through the
external venting, which define an annular gap P4 therebetween. The
gap is typically open to the atmosphere, preventing a breach of
either of the tube walls to allow mixing of the respective fluids.
Therefore the double wall assembly created by the first and second
tubular walls 60A and 60B is located at the boundary between the
working passage and the heat reclaim passage such that the gap in
the double wall assembly defines the safety passage P4 to prevent
the cross contamination of the heat-recovery heat transfer fluid
and working fluid in the event of a failure of a tube wall.
[0241] As in all embodiments, the working passage P2 constraining
the gaseous working fluid will be in fluid connection to the
compressor device and expansion device as described previously.
[0242] Turning now more particularly to the embodiment of FIGS. 10A
through 10C, in this instance the inner tubular wall assembly 50 of
the working passage is a single wall boundary, while the outer
tubular wall assembly 48 of the working passage comprises the
double wall assembly formed of the first and second tubular walls
60A and 60B as described above. The heat reclaim passage P3 is thus
located in the outermost passage between the outer tube wall
assembly 48 of the working passage and the auxiliary tubular wall
62, while the heat rejection passage P1 is located in the innermost
passage constrained by the inner tubular wall assembly 50 of the
working passage.
[0243] Alternatively as shown in FIGS. 11A through 11C however,
with a water-cooled condenser it is possible to interchange the
heat reclaim and heat rejection fluids relative to the embodiment
of FIGS. 10A through 10C. In this instance, the outer tubular wall
assembly 48 comprises a single wall boundary and the inner tubular
wall assembly 50 of the working passage is the double wall assembly
formed by the first and second tubular walls 60A and 60B. The heat
rejection passage P1 is thus located in the outermost passage
between the auxiliary outer wall 62 and the outer tubular wall
assembly 48 of the working passage, and the heat reclaim passage P3
is located in the innermost passage constrained by the inner
tubular wall assembly 50. FIGS. 11A through 11C thus demonstrates a
configuration with the heat transfer fluids interchanged relative
to FIGS. 10A and 10C.
[0244] With the exception of the location of the double wall
assembly, the operation of the condenser 18 of FIGS. 10A to 10C and
11A to 11C are identical. In each instance there are three possible
modes of heat transfer operation within the compound condenser 18
as described in the following.
[0245] i) Heat from the gaseous working fluid is transferred from
P2 through the double wall boundary of the working passage to the
heat reclaim heat sink fluid in P3. Little or no heat is
transferred from the gaseous working fluid in P2 to heat the
rejection fluid in P1. This is accomplished by stopping the flow of
the heat rejection heat transfer fluid through P1, while allowing
the flow of the heat-reclaim heat transfer fluid through P3.
[0246] ii) Heat from the gaseous working fluid is transferred
through the single wall boundary of the working passage from P2 to
the heat-rejection fluid in P1. Little or no heat is transferred
from the working fluid in P2 to the heat reclaim heat transfer
fluid in P3. This is accomplished by stopping the flow of the
heat-reclaim heat transfer fluid through P3, while allowing the
flow of the heat-rejection heat transfer fluid through P1.
[0247] iii) Heat from the gaseous working fluid is transferred from
P2 to both the heat-rejection heat transfer fluid in P1 and the
heat-reclaim heat transfer fluid in P3 simultaneously. This is
accomplished by allowing the flow of both of the heat sink heat
transfer fluids. To control the amount of energy being transferred
to each of the individual heat transfer fluids the flows of the
heat transfer fluids can be varied.
[0248] Regardless of the heat transfer mode, gaseous working fluid
enters the condenser as a superheated gas. While passing through
the condenser the working fluid will first cool sensibly to the
saturation point then with no change in temperature it will
condense to a liquid giving off the latent heat. When fully
condensed additional sensible cooling will occur and the working
fluid will then leave the condenser as a subcooled liquid.
[0249] As with the air-cooled condenser application of the
teachings, with a water-cooled condenser it is possible to
configure the invention with single wall heat exchangers or
multiple heat sink tubes without varying the intent of the
invention. In addition with a water-cooled condenser it is possible
to configure the invention with an additional double wall between
the working fluid and the heat-rejection fluid without varying the
intent of the invention.
[0250] As stated previously, the preceding are exemplary
embodiments of some common condenser designs as well as those same
condenser configurations with possible applications of the
invention.
[0251] These examples are to illustrate the process and or method
of application and are in no way exhaustive of all of the
refrigeration condenser designs in which the invention can be
applied or all of the manners in which it can be applied by a
person skilled in the art.
[0252] When properly designed, the compound multi heat sink
condenser, as disclosed, will result in a multi heat sink
refrigeration system with a fixed active working fluid charge
requirement within the condenser that is largely unaffected by the
ratio of the energy being transferred to each of the heat sinks
allowing the refrigeration system to operate identically to a
single heat sink system.
[0253] FIGS. 12, 13, and 14 illustrate compound multi heat sink
condenser, vapor compression circuit schematics which are
applicable to all of the compound condenser embodiments described
herein and should be contrasted with prior art arrangements in
FIGS. 2 and 3. More particularly, FIGS. 12, 13 and 14 illustrate
simplified, compound multi heat sink condenser, vapor compression
circuit schematics, including graphical depictions of liquid to gas
ratios, active working fluid charge requirements and energy
movement representation in the condensers. In each instance:
[0254] 1) Energy is transferred from an energy (heat) source to a
liquid working fluid, in an evaporator, causing it to
evaporate.
[0255] 2) This gaseous working fluid moves to a compressive device
where the pressure is raised, with the associated increase in
temperature.
[0256] 3) This gaseous working fluid then moves to the condenser,
where the energy can be transferred from the gaseous working fluid
through the condenser to any or all of the multiple heat transfer
fluids, either individually or simultaneously in any ratio, based
on the respective temperature and flow of the heat transfer fluids,
causing the gaseous working fluid to condense. In FIG. 12 energy is
moving from the working fluid in P2 to the first heat transfer
fluid in P1; which in this case is the air in contact with the
fins. In FIG. 13 energy is moving from the working fluid in P2 to
the second heat transfer fluid in P3, which in this case is the
heat-reclaim water constrained in the inner tube. In FIG. 14,
energy is moving from the working fluid in P2 to both heat transfer
fluids in P1 and in P3, simultaneously.
[0257] 4) The liquid working fluid is returned to the evaporator,
through an expansion device either directly or with the addition of
other controls, heat exchangers or devices, to begin the cycle
again.
[0258] As can be seen clearly, by comparing the graphical
depictions of liquid to gas ratios, active working fluid charge
requirements and energy movement representation in the condensers
for each drawing, the heat sink, or sinks, that the energy is
moving to has no impact on the ratio of liquid to gas nor on the
active working fluid charge requirements within the compound
condenser.
[0259] It is understood that while certain forms of the present
invention associated with certain refrigeration processes have been
illustrated and described herein, the invention is not to be
limited to the specific forms, refrigeration processes, or
arrangements of parts described and shown.
[0260] In addition variations of the specific construction and
arrangement of the heat exchanger disclosed above can be made by
those skilled in the art without departing from the invention as
defined in the claims.
[0261] Some examples of these variations include but are not
limited to: i) Multi wall internal piping to meet potable water
requirements in some jurisdictions; ii) Heat transfer enhancements
to the tubing, either internally or externally; including but not
limited to the use of fins; deformation of the tubes and other
methods to increase surface area, etc; iii) The addition of
controls or monitoring equipment to the refrigeration circuit; and
iv) The use of flow control on any, or all, of the condenser heat
transfer fluids.
[0262] Since various modifications can be made in the invention as
herein above described, and many apparently widely different
embodiments of same made within the spirit and scope of the claims
without department from such spirit and scope, it is intended that
all matter contained in the accompanying specification shall be
interpreted as illustrative only and not in a limiting sense.
* * * * *