U.S. patent application number 17/763048 was filed with the patent office on 2022-08-11 for heat exchanger for mixed refrigerant systems.
The applicant listed for this patent is Carrier Corporation. Invention is credited to Richard G. Lord.
Application Number | 20220252311 17/763048 |
Document ID | / |
Family ID | 1000006350978 |
Filed Date | 2022-08-11 |
United States Patent
Application |
20220252311 |
Kind Code |
A1 |
Lord; Richard G. |
August 11, 2022 |
HEAT EXCHANGER FOR MIXED REFRIGERANT SYSTEMS
Abstract
A vapor compression cycle is provided including a compressor,
condenser, expansion device, and evaporator fluidly connected via
one or more fluid conduits, A fluid circulating within the one of
more fluid conduits has a high temperature glide. An intermediate
heat exchanger has a first part including at least one pass there
through and a second part including at least one pass there
through. The first part is arranged downstream from the condenser
and at least a portion of the fluid output from the condenser is
provided to the first part of the intermediate heat exchanger.
Within the first part, a temperature of the at least a portion of
the fluid output from the condenser is reduced.
Inventors: |
Lord; Richard G.;
(Murfreesboro, TN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Carrier Corporation |
Palm Beach Gardens |
FL |
US |
|
|
Family ID: |
1000006350978 |
Appl. No.: |
17/763048 |
Filed: |
September 18, 2020 |
PCT Filed: |
September 18, 2020 |
PCT NO: |
PCT/US2020/051484 |
371 Date: |
March 23, 2022 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62904921 |
Sep 24, 2019 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F25B 41/39 20210101;
F25B 40/02 20130101; F25B 9/006 20130101 |
International
Class: |
F25B 40/02 20060101
F25B040/02; F25B 9/00 20060101 F25B009/00; F25B 41/39 20060101
F25B041/39 |
Claims
1. A vapor compression cycle comprising: a compressor, condenser,
expansion device, and evaporator fluidly connected via one or more
fluid conduits; a fluid circulating within the one of more fluid
conduits, wherein the fluid has a high temperature glide; and an
intermediate heat exchanger having a first part including at least
one pass there through and a second part including at least one
pass there through, wherein the first part is arranged downstream
from the condenser and at least a portion of the fluid output from
the condenser is provided to the first part of the intermediate
heat exchanger, wherein within the first part, a temperature of the
at least a portion of the fluid output from the condenser is
reduced.
2. The vapor compression cycle of claim 1, wherein the high
temperature glide is at least 2.degree. F.
3. The vapor compression cycle of claim 1, wherein the high
temperature glide is at least 5.degree. F.
4. The vapor compression cycle of claim 1, wherein the high
temperature glide is at least 10.degree. F.
5. The vapor compression cycle of claim 1, wherein the fluid
includes a mixture having two or more distinct fluid components
having different boiling temperatures and condensing
temperatures.
6. The vapor compression cycle of claim 5, wherein at least one of
the two or more distinct fluid components is a refrigerant.
7. The vapor compression cycle of claim 5, wherein the refrigerant
is an A2L refrigerant or an A3 refrigerant.
8. The vapor compression cycle of claim 1, wherein the second part
of the intermediate heat exchanger is arranged downstream from and
in fluid communication with an outlet of the evaporator.
9. The vapor compression cycle of claim 8, wherein within the
second part, a temperature of a fluid provided to the second part
of the intermediate heat exchanger from the outlet of the
evaporator is increased.
10. The vapor compression cycle of claim 1, wherein a first portion
of the fluid output from the condenser is provided to the first
part of the intermediate heat exchanger and a second portion of the
fluid output from the condenser is provided to the second part of
the intermediate heat exchanger.
11. The vapor compression cycle of claim 10, further comprising
another expansion device arranged upstream from and in fluid
communication with the second part of the intermediate heat
exchanger, wherein the second portion of fluid output from the
condenser is provided to the another expansion device.
12. The vapor compression cycle of claim 11, wherein the first part
of the intermediate heat exchanger and the another expansion device
are arranged in parallel.
13. The vapor compression cycle of claim 10, wherein the first
portion of fluid output from the condenser is mixed with the second
portion of fluid output from the condenser directly upstream from
the compressor.
14. The vapor compression cycle of claim 10, wherein the second
portion of fluid output from the condenser is configured to bypass
the expansion device and the evaporator.
15. The vapor compression cycle of claim 10, wherein the
intermediate heat exchanger is a refrigerant to refrigerant heat
exchanger.
16. The vapor compression cycle of claim 10, wherein the
intermediate heat exchanger is a liquid suction heat exchanger.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Application No.
62/904,921, filed on Sep. 24, 2019, which is incorporated herein by
reference in its entirety.
BACKGROUND
[0002] Exemplary embodiments disclosed herein relate generally to a
refrigeration system, and more particularly, to a refrigeration
system suitable for use with a refrigerant mixture having a high
temperature glide fluid.
[0003] One of the most common technologies in use for residential
and commercial refrigeration and air conditioning is the vapor
compression refrigerant heat transfer loop. These loops typically
circulate a refrigerant having appropriate thermodynamic properties
through a loop that comprises a compressor, a heat rejection heat
exchanger (i.e., heat exchanger condenser), an expansion device and
a heat absorption heat exchanger (i.e., heat exchanger evaporator).
Vapor compression refrigerant loops effectively provide cooling and
refrigeration in a variety of settings, and in some situations can
be run in reverse as a heat pump.
[0004] It has been determined that commonly used refrigerants, such
as the commonly used R-410A for example, have unacceptable global
warming potential (GWP) such that their use will be phased out for
many HVAC&R applications. There are some Non-flammable, low GWP
refrigerants that could be used to replace the common refrigerant
using in most HVAC comfort cooling products but there are not good
higher pressure refrigerants and many of the options being
evaluated are mixtures that are also mildly flammable and also have
higher glides like R-454B.
BRIEF DESCRIPTION
[0005] According to an embodiment, a vapor compression cycle is
provided including a compressor, condenser, expansion device, and
evaporator fluidly connected via one or more fluid conduits. A
fluid circulating within the one of more fluid conduits has a high
temperature glide. An intermediate heat exchanger has a first part
including at least one pass there through and a second part
including at least one pass there through. The first part is
arranged downstream from the condenser and at least a portion of
the fluid output from the condenser is provided to the first part
of the intermediate heat exchanger. Within the first part, a
temperature of the at least a portion of the fluid output from the
condenser is reduced.
[0006] In addition to one or more of the features described above,
or as an alternative, in further embodiments the high temperature
glide is at least 2.degree. F.
[0007] In addition to one or more of the features described above,
or as an alternative, in further embodiments the high temperature
glide is at least 5.degree. F.
[0008] In addition to one or more of the features described above,
or as an alternative, in further embodiments the high temperature
glide is at least 10.degree. F.
[0009] In addition to one or more of the features described above,
or as an alternative, in further embodiments the fluid includes a
mixture having two or more distinct fluid components having
different boiling temperatures and condensing temperatures.
[0010] In addition to one or more of the features described above,
or as an alternative, in further embodiments at least one of the
two or more distinct fluid components is a refrigerant.
[0011] In addition to one or more of the features described above,
or as an alternative, in further embodiments the refrigerant is an
A2L refrigerant or an A3 refrigerant.
[0012] In addition to one or more of the features described above,
or as an alternative, in further embodiments the second part of the
intermediate heat exchanger is arranged downstream from and in
fluid communication with an outlet of the evaporator.
[0013] In addition to one or more of the features described above,
or as an alternative, in further embodiments within the second
part, a temperature of a fluid provided to the second part of the
intermediate heat exchanger from the outlet of the evaporator is
increased.
[0014] In addition to one or more of the features described above,
or as an alternative, in further embodiments a first portion of the
fluid output from the condenser is provided to the first part of
the intermediate heat exchanger and a second portion of the fluid
output from the condenser is provided to the second part of the
intermediate heat exchanger.
[0015] In addition to one or more of the features described above,
or as an alternative, in further embodiments comprising another
expansion device arranged upstream from and in fluid communication
with the second part of the intermediate heat exchanger, wherein
the second portion of fluid output from the condenser is provided
to the another expansion device.
[0016] In addition to one or more of the features described above,
or as an alternative, in further embodiments the first part of the
intermediate heat exchanger and the another expansion device are
arranged in parallel.
[0017] In addition to one or more of the features described above,
or as an alternative, in further embodiments the first portion of
fluid output from the condenser is mixed with the second portion of
fluid output from the condenser directly upstream from the
compressor.
[0018] In addition to one or more of the features described above,
or as an alternative, in further embodiments the second portion of
fluid output from the condenser is configured to bypass the
expansion device and the evaporator.
[0019] In addition to one or more of the features described above,
or as an alternative, in further embodiments the intermediate heat
exchanger is a refrigerant to refrigerant heat exchanger.
[0020] In addition to one or more of the features described above,
or as an alternative, in further embodiments the intermediate heat
exchanger is a liquid suction heat exchanger.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The following descriptions should not be considered limiting
in any way. With reference to the accompanying drawings, like
elements are numbered alike:
[0022] FIG. 1 is a schematic diagram of a basic vapor compression
cycle of a heating, ventilation, air conditioning and refrigeration
(HVAC&R);
[0023] FIG. 2 is an example of a temperature/enthalpy chart of a
fluid having a high temperature glide according to an
embodiment:
[0024] FIG. 3 is a schematic diagram of a vapor compression cycle
suitable for use with a fluid having a high temperature glide
according to an embodiment; and
[0025] FIG. 4 is a schematic diagram of another vapor compression
cycle suitable for use with a fluid having a high temperature glide
according to an embodiment.
DETAILED DESCRIPTION
[0026] A detailed description of one or more embodiments of the
disclosed apparatus and method are presented herein by way of
exemplification and not limitation with reference to the
Figures.
[0027] Referring now to FIG. 1, a basic vapor compression or
refrigeration cycle 10 of a heating, ventilation, air conditioning
and refrigeration (HVAC&R) system is schematically illustrated.
Examples of HVAC&R systems include split, packaged, and rooftop
systems, for example. A fluid, such as a refrigerant R-410A for
example, is configured to circulate through the vapor compression
cycle 10 such that the refrigerant R absorbs heat when evaporated
at a lower temperature and pressure in heat exchanger 18 and
releases heat when condensing at a higher temperature and pressure
in heat exchanger 14. Within this cycle 10, the refrigerant R flows
in a counterclockwise direction as indicated by the arrows. The
compressor 12 receives refrigerant vapor from the evaporator 18 and
compresses it to a higher temperature and pressure, with the
relatively hot vapor then passing to the condenser 14 where it is
cooled and condensed to a liquid state and partially subcools by a
heat exchange relationship with a cooling medium such as air or
water. The subcooled liquid refrigerant R then passes from the
condenser 14 to an expansion device 16, such as an expansion valve,
wherein the refrigerant R is expanded to a low temperature two
phase liquid/vapor state as it passes to the evaporator 18. The low
pressure vapor then returns to the compressor 12 so that the cycle
may be repeated.
[0028] Various types of refrigerants are available for use in a
vapor compression cycle. These refrigerants may include either a
single fluid, or alternatively, may include a fluid mixture or
blend including two or more distinct fluid components. The distinct
components of these refrigerant blends can have different boiling
temperatures and condensing temperatures, and can result in a
temperature glide as shown in FIG. 2. The greater difference in the
boiling and condensing temperatures increases the amount of
temperature glide.
[0029] Temperature glide is defined as the temperature difference
between the starting and ending temperature of a refrigerant phase
change within a system at a constant pressure. In existing
HVAC&R systems, the refrigerant typically used is either an
azeotropic refrigerant or a near-azeotropic refrigerant blend. An
azeotropic refrigerant is typically a single refrigerant fluid and
does not experience a temperature glide and the boiling and
condensing temperature of each component are close in temperature.
A near-azeotropic refrigerant blend experiences a very small amount
of temperature glide as it condenses and evaporates in a vapor
compression cycle, such as less than one degree for example.
Accordingly, the temperature glide of a near-azeotropic refrigerant
blend does not significantly impact the operation of the vapor
compression cycle.
[0030] In embodiments where the fluid configured to circulate
through the vapor compression cycle is a refrigerant mixture or
blend having a high temperature glide, the refrigerant blend is
considered zeotropic. As used herein, the term "high temperature
glide" includes refrigerant blends having a temperature glide of at
least two degrees, such as at least three degrees, at least four
degrees, at least five degrees, or at least ten degrees for
example. In such embodiments, a refrigerant of the refrigerant
blend can also be an A2L refrigerant or an A3 refrigerant. In an
embodiment, the refrigerant blend includes refrigerant R-454B;
however, it should be understood that R-454B is intended as an
example, and the zeotropic refrigerant or refrigerant blend
disclosed herein is not limited to this specific refrigerant.
Although a refrigerant blend is described herein as having a high
temperature glide, it should be understood that other suitable
refrigerants, fluids, or mixtures thereof that similarly have a
high temperature glide are also within the scope of the
disclosure.
[0031] An example of a temperature enthalpy diagram of a
refrigerant mixture or blend having high glide is illustrated in
FIG. 2. As shown, the temperature glide exists during both
condensing and evaporation of the refrigerant mixture. The
temperature glide of a zeotropic refrigerant blend negatively
affects operation of a basic vapor compression cycle. For example,
as a result of the temperature glide, it is difficult to get
adequate state point subcooling within a condenser required for
proper operation of the downstream expansion valve. Similarly, the
temperature glide of a zeotropic refrigerant blend makes it
difficult to achieve sufficient superheat required for proper
operation of the compressor and control of the expansion valve.
[0032] With reference now to FIGS. 3 and 4, schematic diagrams of a
vapor compression cycle 30 of an HVAC&R system suitable for use
with a zeotropic refrigerant blend, shown by RM, are illustrated
according to various embodiments. As previously described, the
vapor compression cycle 30 includes a compressor 32, a heat
rejection heat exchanger or condenser 34, an expansion device 36,
and a heat absorption heat exchanger or evaporator 38. As shown in
FIG. 3, the vapor compression cycle 30 additionally includes an
intermediate heat exchanger 40 configured to further increase the
heat transfer of the refrigerant blend RM. In an embodiment, the
intermediate heat exchanger 40 is a refrigerant to refrigerant
liquid suction heat exchanger configured to use a cold gaseous
fluid to subcool the liquid refrigerant blend output from the
condenser 32.
[0033] In the illustrated, non-limiting embodiment of FIG. 3, the
intermediate heat exchanger 40 is positioned within the suction
line extending between the evaporator 38 and the compressor 32.
Accordingly, the gaseous refrigerant blend output from the
evaporator 38 makes a pass through a second part of the
intermediate heat exchanger 40 before ultimately being supplied to
the compressor 32. In an embodiment, the intermediate heat
exchanger 40 is positioned upstream from the thermal expansion
device 36 and directly downstream from the condenser 34. The
refrigerant blend provided to a first part of the intermediate heat
exchanger 40 from the condenser 34 may be a liquid, or
alternatively, in some instances may be a two phase mixture of both
liquid and gas if adequate subcooling is not possible in the
condenser due to the high glide of the refrigerant.
[0034] As the condensed refrigerant blend passes through the first
part of the intermediate heat exchanger 40, heat transfers from the
condensed refrigerant blend to the vaporized or gaseous refrigerant
blend output from the evaporator 38. As a result of this heat
transfer, the condensed liquid refrigerant blend is further
subcooled, such as below the ambient temperature. At the same time,
the vaporized refrigerant blend is superheated, thereby allowing
the evaporator 38 to run at or near a fully saturated condition,
which enhances operation of the evaporator.
[0035] In another embodiment, illustrated in FIG. 4, the
intermediate heat exchanger 40 is fluidly coupled to an outlet of
the condenser 32 and is arranged in parallel with another thermal
expansion valve 42. A first portion of the refrigerant blend output
from the condenser 34, illustrated by RM1, is provided to a first
part of the downstream intermediate heat exchanger 40 and a second
portion of the refrigerant blend output from the condenser 34,
illustrated by RM2, is provided to the expansion device 42. The two
phase flow of refrigerant blend output from the expansion device 42
is then provided to a second part of the intermediate heat
exchanger 40. Within the intermediate heat exchanger 40, heat
transfers from the first portion of the refrigerant blend RM1 to
the at least partially vaporized or gaseous second portion of the
refrigerant blend RM2 output from the expansion valve 42. As a
result of this heat transfer, the first portion of the refrigerant
blend RM1 is further subcooled, such as below the ambient
temperature for example, and the second portion of the refrigerant
blend RM2 is superheated. It should be understood that each of the
first and second parts of the intermediate heat exchanger 40
illustrated and described herein may include a single pass, or
alternatively, may include multiple passes to achieve the desired
amount of heat transfer.
[0036] The subcooled first portion of the refrigerant blend RM1 may
then be provided to one or more downstream components, such as the
expansion device 36, evaporator 38, and/or compressor 32 for
example. The second portion of the refrigerant blend RM2 output
from the intermediate heat exchanger 40 is rejoined with the first
portion of the refrigerant blend RM1 when the first portion of the
refrigerant blend RM1 has a generally gaseous configuration. In an
embodiment, the first portion and the second portion of the
refrigerant blend RM1, RM2 are joined directly upstream from the
inlet of the compressor 32. The refrigerant can then be sent to the
compressor 32 suction or it can be introduced into an economizer
port of the compressor 32 which is part way thru the compression
process.
[0037] A vapor compression cycle 30 as illustrated and described
herein has enhanced performance when used with a refrigerant blend
having a high temperature glide compared to a basic vapor
compression system. Further, in embodiments where the HVAC&R
system is a split system having long fluid lines, the subcooling of
the refrigerant within the intermediate heat exchanger 40 may
additionally reduce the refrigerant charge.
[0038] The term "about" is intended to include the degree of error
associated with measurement of the particular quantity based upon
the equipment available at the time of filing the application.
[0039] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the present disclosure. As used herein, the singular forms "a",
"an" and "the" are intended to include the plural forms as well,
unless the context clearly indicates otherwise. It will be further
understood that the terms "comprises" and/or "comprising," when
used in this specification, specify the presence of stated
features, integers, steps, operations, elements, and/or components,
but do not preclude the presence or addition of one or more other
features, integers, steps, operations, element components, and/or
groups thereof.
[0040] While the present disclosure has been described with
reference to an exemplary embodiment or embodiments, it will be
understood by those skilled in the art that various changes may be
made and equivalents may be substituted for elements thereof
without departing from the scope of the present disclosure. In
addition, many modifications may be made to adapt a particular
situation or material to the teachings of the present disclosure
without departing from the essential scope thereof. Therefore, it
is intended that the present disclosure not be limited to the
particular embodiment disclosed as the best mode contemplated for
carrying out this present disclosure, but that the present
disclosure will include all embodiments falling within the scope of
the claims.
* * * * *