CN109073283B

CN109073283B - Water-cooled refrigerated transport system

Info

Publication number: CN109073283B
Application number: CN201780025979.XA
Authority: CN
Inventors: J.D.斯卡塞拉; T.J.贝内迪特
Original assignee: Carrier Corp
Current assignee: Carrier Corp
Priority date: 2016-04-27
Filing date: 2017-04-24
Publication date: 2021-08-03
Anticipated expiration: 2037-04-24
Also published as: WO2017189420A1; CN109073283A; SG11201808754UA; EP3449193A1; US20190128568A1

Abstract

A refrigeration system (30) includes a compressor (36) for driving refrigerant along a refrigerant flowpath (34) and having a first stage (36A) and a second stage (36B). The first heat exchanger (38) is along the refrigerant flowpath. The intercooler heat exchanger (120) is along the refrigerant flow path. The second heat exchanger (42) is along the refrigerant flow path. An additional heat exchanger (170) is along the refrigerant flowpath between the second stage of the compressor and the first heat exchanger.

Description

Water-cooled refrigerated transport system

Cross Reference to Related Applications

The benefit of U.S. patent application No. 62/328,206, entitled "Water-Cooled referred Transport System," filed 2016, month 4, and day 27, the disclosure of which is incorporated herein by reference in its entirety as if set forth in detail.

Background

The present disclosure relates to refrigerated transport systems, such as intermodal containers. More particularly, the present disclosure relates to such refrigerated transport systems having a water cooling mode.

An exemplary refrigerated intermodal container (also referred to as a shipping container or an intermodal shipping container) has an equipment module at one end of the container. The equipment module includes a vapor compression system having a compressor, a heat rejection heat exchanger downstream of the compressor along a refrigerant flowpath, an expansion device, and a heat absorption heat exchanger. One or more first fans may drive the flow of external air across the heat rejection heat exchanger. One or more second fans may drive the internal airflow across the heat absorption heat exchanger. In various implementations, to power the container, there may be a power cord for connecting to an external power source. The equipment modules may be preformed as modules that are matable with the remainder of the container body (e.g., insertable into the open front end of the body) for ease of manufacture or maintenance. One example of such a container refrigeration system is sold under the trademark natura line by Carrier Corporation of Farmington, connecticut. One example of such a system is seen in U.S. patent application 62/098144 to Rau, filed on 30/12/2014 and entitled "Access Panel," the disclosure of which is incorporated herein by reference in its entirety as if set forth in detail. Additionally, refrigerated cars, refrigerated railcars, and the like may have refrigeration systems with different forms or degrees of modularity.

Several models of equipment with optional water cooled condensers (gas coolers of the R-744 unit) are sold. The water-cooled heat exchanger is located downstream of the air-cooled heat rejection heat exchanger along a refrigerant flowpath from the compressor. Water cooling is used in high ambient temperature conditions where the air flow over the air-cooled heat rejection heat exchanger is insufficient. One example is a ship board, where water is supplied from a ship's water supply system that provides a recirculating flow of water and rejects heat to an external aquatic environment (e.g. sea water). Water cooling is seen as an expensive option with limited market acceptance.

Furthermore, several models of equipment modules have two compressor stages with intercooling. In an exemplary configuration, the intercooler heat exchanger is a refrigerant-to-air heat exchanger positioned along the outside air flow path downstream of the heat rejection heat exchanger. The natura line module integrates an intercooler and a heat rejection heat exchanger in a single Round Tube Plate Fin (RTPF) unit. Water cooling such units presents the added expense of adding a second refrigerant-water heat exchanger for intercooling.

Disclosure of Invention

One aspect of the present disclosure is directed to a refrigeration system including a compressor for driving a refrigerant along a refrigerant flowpath and having a first stage and a second stage. The first heat exchanger is along the refrigerant flowpath. The intercooler heat exchanger is along the refrigerant flow path. The second heat exchanger is along the refrigerant flowpath. The additional heat exchanger is along a refrigerant flowpath between the second stage of the compressor and the first heat exchanger.

In one or more embodiments of any of the preceding embodiments, the additional heat exchanger is a refrigerant-water heat exchanger.

In one or more embodiments of any of the preceding embodiments, the system is devoid of other refrigerant-water heat exchangers.

In one or more embodiments of any of the preceding embodiments, the additional heat exchanger is a brazed plate heat exchanger.

In one or more embodiments of any of the preceding embodiments, the liquid supply fitting and the liquid return fitting are along a liquid flow path through the additional heat exchanger.

In one or more embodiments of any of the preceding embodiments, the first heat exchanger and the intercooler heat exchanger are fin-and-tube heat exchangers sharing fins.

In one or more embodiments of any of the preceding embodiments, the first heat exchanger and the intercooler heat exchanger are in series along the air flow path.

In one or more embodiments of any of the preceding embodiments, the first electric fan is positioned to drive the first air flow across the first heat exchanger and the intercooler heat exchanger, and the second electric fan is positioned to drive the second air flow across the second heat exchanger.

In one or more embodiments of any of the foregoing embodiments, the refrigeration system is a refrigeration module mountable to an end of the intermodal container.

In one or more embodiments of any of the preceding embodiments, the refrigerated transport system includes a refrigeration system. The refrigerated transport system also includes a body enclosing the refrigerated compartment. The first heat exchanger is positioned to reject heat to the outside environment in the first cooling mode. The second heat exchanger is positioned to absorb heat from the refrigerated compartment in the first cooling mode.

In one or more embodiments of any of the preceding embodiments, the controller is configured to turn off the first electric fan in response to sufficient sensed water pressure in the additional heat exchanger.

In one or more embodiments of any of the preceding embodiments, the body comprises: a pair of side walls; a top portion; a bottom; and one or more doors.

In one or more embodiments of any of the preceding embodiments, the refrigerated transport system is a refrigerated intermodal shipping container. The one or more doors include a pair of hinged doors at a first end of the body. The refrigeration system is mounted in the equipment box at a second end of the main body opposite the first end.

Another aspect of the present disclosure relates to a vessel, comprising: a hull; a plurality of refrigerated intermodal shipping containers in or on the hull; and a cooling water supply system. The cooling water supply system includes: one or more heat exchangers positioned to transfer heat between the seawater and the heat transfer fluid; and a supply/return system of heat transfer fluid comprising one or more pumps for driving a flow of heat transfer fluid and conduits terminating in respective supply and return conduits coupled to the additional heat exchanger.

In one or more embodiments of any of the preceding embodiments, the heat transfer fluid is grey water.

In one or more embodiments of any of the preceding embodiments, the method for operating a refrigeration system or a refrigerated transport system includes, in a first mode: operating a compressor to drive a refrigerant along a refrigerant flowpath, the refrigerant passing through an intercooler heat exchanger between a first stage and a second stage; passing the refrigerant through an additional heat exchanger to reject heat from the refrigerant to the fluid stream; passing a refrigerant through a first heat exchanger; and passing the refrigerant through a second heat exchanger along a refrigerant flowpath to absorb heat.

In one or more embodiments of any of the preceding embodiments, there is no forced air flow across the first heat exchanger and the intercooler heat exchanger.

In one or more embodiments of any of the preceding embodiments, in the first mode, the fluid flow is water flow.

In one or more embodiments of any of the preceding embodiments, the method further comprises, operating in the second mode comprises: operating a compressor to drive a refrigerant along a refrigerant flowpath, the refrigerant passing through an intercooler heat exchanger between a first stage and a second stage; passing the refrigerant through an additional heat exchanger; passing the refrigerant through a first heat exchanger to reject heat; and passing the refrigerant through a second heat exchanger along a refrigerant flowpath to absorb heat.

In one or more embodiments of any of the preceding embodiments, in the second mode, the first mode fluid flow is disabled and the air flow is driven across the first heat exchanger and the intercooler.

The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims.

Drawings

Fig. 1 is a cross-sectional view of a refrigerated cargo container.

Fig. 2 is a rear view of the refrigerated cargo container.

Fig. 3 is a schematic view of a refrigeration system for a refrigerated cargo container.

Fig. 4 is a front view of the refrigeration unit of the container of fig. 1.

Fig. 5 is a schematic side sectional view of a refrigerated cargo container.

FIG. 6 is a partial view of a subassembly of an air-cooled condenser/intercooler and a water-cooled condenser.

Fig. 7 is a partial cross-sectional view of the air-cooled condenser/intercooler taken along line 7-7.

Fig. 8 is a simplified view of a container ship.

Fig. 9 is a simplified partial schematic view of a cooling water supply system of a ship.

Like reference numbers and designations in the various drawings indicate like elements.

Detailed Description

Fig. 1 shows an intermodal container 20 that may be shipped, truck loaded, train loaded, etc. The container has a body 22 enclosing an interior 24. The body and the interior are substantially formed as a right hexahedron. The body has a top 22A, a bottom 22B, a first side 22C, a second side 22D, a first end 22E, and a second end 22F. The top, bottom and sides may be a unitary rigid metallic structural system. The first end may be closed by an equipment module 26 ("equipment box"). The second end may be substantially formed by a pair of oppositely hinged

doors

28A, 28B (fig. 2).

The exemplary pair of

rear doors

28A, 28B (fig. 2) are hinged to adjacent sides along their outboard edges and meet at their outboard edges. To secure the doors in place, each door has a pair of vertically oriented locking bars mounted in sleeves for rotation about their central vertical axes. At the upper and lower ends, each locking bar has a cam that can interact with an associated complementary positioning element mounted in the respective sill and sill. As the doors rotate between their open and closed conditions, the locking bar may rotate about 90 ° or up to about 180 ° between a locked condition, in which the cam is interlocked with the keeper, and an unlocked condition, in which the cam may pass freely from the keeper.

The equipment module contains a vapor compression refrigeration system 30 (fig. 3). The exemplary system uses a carbon dioxide based refrigerant, such as R-744. The illustrated example includes, in sequence along a major portion of the refrigerant flowpath 34, a compressor 36, a heat rejection heat exchanger 38, an expansion device 40 (e.g., an electronic expansion valve, a thermal expansion valve, an orifice, etc.), and a heat absorption heat exchanger 42. The one or more first fans 50 may drive the flow of external air 520 across the heat rejection heat exchanger. The heat rejecting heat exchanger is therefore called an air-cooled condenser (ACC). The term "condenser" is used in a broad sense in the art to comprehend both real and gas condensers. One or more

second fans

52A, 52B (fig. 3 and 4) may drive the internal air streams 522A, 522B across the heat absorption heat exchangers along the

respective flow paths

510A, 510B.

In various implementations, to power the container, there may be a power cord (not shown) for connecting to an external power source. For example, the external power source may be from a ship or truck-trailer carrying the container or may be from a facility or site in which the container is stored. Further, the container may be associated with a generator 60 (fig. 3, e.g., with an internal combustion engine). For a conventional container, the generator may be part of an attached "generator set" that is separately mountable to the vehicle (trailer or rail car) carrying the container. Other transport refrigeration systems, such as a dedicated trailer, may integrate a generator into the body of equipment mounted to the front of the trailer box. The refrigeration system may include a main controller 64 (e.g., having a processor, memory, and storage device for running programs to perform desired functions) powered by a main battery 66. The battery is typically a rechargeable battery that is charged when the container is plugged into an external power source or running generator set.

The equipment modules may be preformed as modules that are matable with the remainder of the container body (e.g., insertable into the open front end of the body) for ease of manufacture or maintenance.

The module 26 includes a front panel or panel assembly 70 (fig. 4). In fig. 1 and 4, the lower right (in the drawings; to the left on the container) panel of the assembly 70 is shown cut away. On the left side of the drawing, the lower panel is removed to expose the various components. The panel assembly 70 may have a plurality of openings, some of which may be closed by various means. Two of the openings are along the

air flow paths

510A, 510B of the two

evaporator fans

52A and 52B. These flow paths may be isolated from each other or may be only adjacent halves of a single flow path (or may be combined, separated, and merged). In this example, the opening spans the fan such that a portion of the opening is upstream of the fan and a portion of the opening is downstream. The openings are closed by

respective access passages

80A, 80B (fig. 4). The exemplary faceplate 80A includes a rotary gate valve (e.g., manual or motorized) for providing a vent for fresh air exchange. It may also have a small blower fan 81A to draw air from the flow path 510A (or may rely on leakage past an adjacent evaporator fan). Other valve/gate configurations may be provided. The illustrated faceplate 80B lacks any vents/valves and/or blowers, but may have one.

The exemplary system 30 is a heat-conserving system. The exemplary economized system has a compressor as a two-stage compressor with respective first and

second stages

36A and 36B. In the exemplary embodiment, first stage 36A and second stage 36B are a low pressure stage and a high pressure stage, respectively. The exemplary stage is typically powered by an electric motor 37. For example, the stages may be individual banks of cylinders of a reciprocating compressor. Fig. 3 shows a compressor having a total suction port 90 and a total discharge port 92. The economizer ports are labeled 94. The exemplary economizer involves a flash tank economizer subsystem 100 located between the heat rejection heat exchanger 38 and the expansion device 40. The exemplary system 100 includes a flash tank 102 having a liquid outlet 104 for feeding the expansion device 40 and a steam outlet 106 for feeding saturated steam along an economizer line 108 to the economizer port 94. Typically, the mixing of the saturated steam helps to cool (lower) the temperature of the refrigerator leaving the first stage. This, together with the charge air cooler, serves to reduce that temperature to prevent the second stage temperature (exhaust temperature) from becoming too high. The economizer expansion device 110 may be integrated with the flash tank or upstream of the inlet 112 of the flash tank. The exemplary expansion device 110 is a conventional high pressure expansion valve.

The exemplary refrigeration system is also an intercooler system having an intercooler heat exchanger 120. The intercooler heat exchanger may be between the first and

second stages

36A, 36B along the chiller flow path in some modes of operation. An exemplary intercooler heat exchanger (intercooler) 120 is a refrigerant-to-air heat exchanger. The exemplary refrigerant-air heat exchanger is along an outside air flow path 508. In an exemplary embodiment, the intercooler heat exchanger 120 is downstream of the heat rejection heat exchanger 38 along the flow path 508. As discussed further below, the

heat exchangers

38 and 120 may be integrated into a single air-cooled condenser/intercooler unit 121 (fig. 6) having separate legs 124 associated with the

heat exchanger

38 and 126 associated with the heat exchanger 120. An exemplary combined unit is a finned tube heat exchanger (e.g., round tube sheet fin (RTPF)), where the metal fins 128 and tube sheet are shared by two sets of tube legs. Other configurations may mix the tubes, and the exact balance of the tubes associated with the respective legs may be determined by various performance factors.

An intercooler is positioned along an interstage line 130 (FIG. 3) forming interstage leg 34-1 of flow path 34. An interstage line extends from a port 134 on the compressor. In the exemplary intermediate cold and economized embodiments, the intercooler line 130 merges with the economizer line 108 such that an intercooler refrigerant stream may be returned to the second stage via the economizer port 94.

FIG. 3 illustrates a number of additional features that may be conventional in baseline economized and cooled systems. These include a valve 140 along the economizer line (e.g., an economizer solenoid valve) that can selectively allow and block economizer flow. Check valve 142 along the economizer line prevents reverse flow through port 106. An unloader valve 144 (e.g., an unloader solenoid valve) is positioned along an unloader line 146 that extends from the second stage inlet (economized port) condition back to the first stage inlet (suction port 90) condition. In the exemplary embodiment, this is shown as extending between the junction of

lines

108 and 130 and the suction line upstream of suction port 90. Physical arrangements other than those shown can achieve the same jet conditions.

One of the other conventional features is a filter/dryer 150, a high side charge port 152, a low side charge port 153, a low side pressure relief valve 154, a high side pressure relief valve 156, various pressure sensors 158, various temperature sensors 160, and a flash pressure relief valve 162.

The system 30 adds a water cooled heat rejection heat exchanger 170 (also known as a water cooled condenser) upstream of the heat rejection heat exchanger 38 along the refrigerant flowpath to the exemplary baseline refrigeration system. The heat exchanger 170 places the water flow path 172 in an exchange relationship with the refrigerant flowing therethrough. While the term "water" is used as the actual substance, the flow in the flow path 172 is generally not pure water, but may have one or more of a variety of additives for bacteria control, corrosion inhibition, freeze protection, pump lubrication, and the like. This water is identified in the art as "grey water". Fig. 3 shows an inlet fitting 174 and an outlet fitting 176 along a flow path 172. The water pressure sensor 178 may be somewhere along the flow path 172 between the fittings. As discussed below, these may be connected to respective supply and return

lines

180, 182 via respective fittings 184, 186 (e.g., automatic drain quick connect fittings) to supply cold water and return hot water. To prevent misconnection, the

fittings

174 and 176 may be different from each other, e.g., of opposite gender.

The system 30 may have one or more non-water cooling modes in which there is no flow along the flow path 172. These may include one or more heat-conserving modes and one or more non-heat-conserving modes.

The system 30 also has at least one mode in which there is water flow along the flow path 172. This will occur, for example, when the container is on a ship, as discussed below. In the case of containers stacked in a ship, the inlet air flow along the flow path 508 may have relatively hot air due to poor circulation. Due to the lack of heat rejection via the heat exchanger 170, the system 30 may not be able to cool the container in those situations. Similarly, an extreme outdoor temperature may overwhelm the basic capacity of the system otherwise. In such a case, the flow along flow path 170 pre-cools the refrigerant entering heat exchanger 38. Depending on the circumstances, this cooling may be to a temperature below the temperature of the ambient air.

Typically, the control may generally reflect existing control protocols for water cooled refrigerated containers and heat/inter-cooled containers. As in conventional water-cooled systems, the pressure sensor 178 may be used by the controller to determine when to switch to water-cooled mode. When the threshold water pressure is sensed, the controller may cut power to the condenser fan 50 while continuing to operate the compressor, evaporator fan, and other components normally. When the water pressure is not sensed, the controller will operate the condenser normally.

The cooling of the refrigerant entering the heat exchanger 38 allows for indirect cooling of the refrigerant passing along the intercooler circuit 34-1. For example, rather than rejecting heat to the air flow 520, the heat exchanger 38 may absorb heat from the air flow 520 and allow the intercooler heat exchanger 120 to reject heat to the air flow 520 again. Another mechanism or kinetics is direct heat transfer via heat from the intercooler heat exchanger to the heat exchanger 38. As mentioned above, the

heat exchangers

38 and 120 may be two sections of a single physical unit. For example, the single unit may be a plate fin heat exchanger, wherein the two sections are formed from different individual tube legs 124, 126 (fig. 7), but share fins 128. The fins may conduct heat from the intercooler heat exchanger section tubes to the heat exchanger section 38 tubes. In such a case, the fan 50 may be turned off to prevent the air flow 520. It is thus seen that by positioning the water-cooled condenser 170 upstream of the air-cooled condenser 38, the water-cooled condenser 170 may provide direct cooling of the refrigerant along the main flow path and indirect cooling of the refrigerant along the intercooler flow path to allow intercooled operation in the water-cooled mode. This avoids the need to provide a second water cooled heat exchanger along the intercooler flow path 34-1, for example.

Fig. 8 shows a cargo ship 600 carrying a plurality of containers 602 stacked on the top side and a plurality of containers 604 in compartments in the interior of the hull 606 of the ship. Illustratively, the chilled water system 618 on-board the vessel includes a seawater side 620 that includes one or more intake ports 622 for drawing in seawater and one or more exhaust ports 624 for discharging seawater. One or more pumps 626 may drive a flow of seawater from an inlet to an outlet and through the seawater side of the one or more water-water heat exchangers 630. On the grey water side 640, one or more pumps 642 drive flow through the grey water side of the heat exchanger 630. The various supply and return

manifold structures

660, 662 may ultimately terminate in separate supply lines 180 and return lines 182 for separate containers. Other details such as various filters, sanitizers, expansion tanks/buffers, etc., are not shown, but may be included, as is known or as yet developed in the art.

The system may be fabricated using materials and techniques that are otherwise conventional or have not been developed.

The use of "first," "second," etc. in this description and in the claims is for distinguishing between claims and not necessarily for indicating relative or absolute importance or chronological order. Similarly, an element identified as "first" (or a similar designation) in a claim for one element does not prevent such "first" element from identifying an element referred to as "second" (or a similar designation) in another claim or in this description.

One or more embodiments are described. Nevertheless, it will be understood that various modifications may be made. For example, when applied to existing basic refrigeration systems and/or container structures and associated methods of use, details of such existing configurations or its associated use may influence details of a particular implementation. Accordingly, other embodiments are within the scope of the following claims.

Claims

1. A refrigeration system (30), comprising:

a compressor (36) for driving refrigerant along a refrigerant flowpath (34), the compressor (36) having a first stage (36A) and a second stage (36B);

a first heat exchanger (38) along the refrigerant flowpath;

an intercooler heat exchanger (120) along the refrigerant flowpath;

a second heat exchanger (42) along the refrigerant flowpath; and

an additional heat exchanger (170) along the refrigerant flowpath between the compressor second stage and the first heat exchanger;

characterized in that the first heat exchanger and the intercooler heat exchanger are tube and fin heat exchangers sharing fins (128).

2. The refrigeration system of claim 1, wherein:

the additional heat exchanger (170) is a refrigerant-water heat exchanger.

3. The refrigeration system of claim 1, wherein:

the system has no other refrigerant-water heat exchanger.

4. The refrigeration system of any of claims 1-3, wherein:

the additional heat exchanger (170) is a brazed plate heat exchanger.

5. The refrigeration system of any of claims 1-3, further comprising:

a liquid supply fitting (174) and a liquid return fitting (176) along a liquid flow path (172) through the additional heat exchanger (170).

6. The refrigeration system of any of claims 1-3, wherein:

the first heat exchanger (38) and the intercooler heat exchanger (120) are in series along an air flow path (508).

7. The refrigeration system of any of claims 1-3, further comprising:

a first electric fan (50) positioned to drive a first air flow across the first heat exchanger (38) and the intercooler heat exchanger (120); and

a second electric fan (52A, 52B) is positioned to drive a second air flow across the second heat exchanger (42).

8. The refrigeration system of claim 7, being a refrigeration module mountable to an end of an intermodal container (20).

9. A refrigerated intermodal shipping container (20) including the refrigeration system of any preceding claim.

10. A method for operating the refrigeration system of any of claims 1-8, the method comprising in a first mode:

operating the compressor (36) to drive the refrigerant along the refrigerant flowpath (34), the refrigerant passing through the intercooler heat exchanger (120) between the first and second stages;

passing the refrigerant through the additional heat exchanger (170) to reject heat from the refrigerant to a fluid stream;

passing the refrigerant through the first heat exchanger (38); and

passing the refrigerant through the second heat exchanger (42) along the refrigerant flowpath to absorb heat.

11. The method for operating a refrigeration system of claim 10, wherein in the first mode:

there is no forced air flow over the first heat exchanger (38) and the intercooler heat exchanger (120).

12. The method for operating a refrigeration system of claim 10 or claim 11, wherein:

in the first mode:

the fluid flow is a water flow.

13. The method for operating a refrigeration system of claim 10 or claim 11, further comprising operating in a second mode comprising:

passing the refrigerant through the additional heat exchanger (170);

passing the refrigerant through the first heat exchanger (38) to reject heat; and

14. The method for operating a refrigeration system of claim 13, wherein:

in the second mode of operation, the first mode of operation,

the first mode fluid flow is disabled; and

an air flow is driven across the first heat exchanger (38) and the intercooler heat exchanger (120).

15. A vessel (600) comprising:

a hull (606);

a plurality of refrigerated intermodal shipping containers (20) according to claim 9 in or on the hull; and

a cooling water supply system, comprising:

one or more heat exchangers (630) positioned to transfer heat between the seawater and the heat transfer fluid; and

a supply/return system of the heat transfer fluid comprising one or more pumps (642) for driving a flow of the heat transfer fluid and conduits terminating in respective supply (180) and return (182) conduits coupled to the additional heat exchanger (170).