WO2019050736A1

WO2019050736A1 - Receiver assembly and heat pump system having the same

Info

Publication number: WO2019050736A1
Application number: PCT/US2018/048507
Authority: WO
Inventors: Guangyu SHEN; Jingkai WENG
Original assignee: Carrier Corporation
Priority date: 2017-09-08
Filing date: 2018-08-29
Publication date: 2019-03-14
Also published as: EP3679309B1; ES2934321T3; US20210063059A1; CN207556037U; EP3679309A1

Abstract

An accumulator assembly and a heat pump system. The accumulator assembly comprises: an accumulator tank body, wherein an inlet and outlet port is disposed at the bottom of the tank body and is flush therewith; and a connecting pipe, having a first end connected to the inlet and outlet port, and a second end for connection to an air conditioning system. According to the accumulator assembly of the present invention, because the inlet and outlet port is flush with the bottom of the accumulator tank body, in the case where all the refrigerant is needed for the operation of the system, refrigerant and lubricating oil accumulated within the accumulator tank body can be completely drained from the tank body, thus ensuring sufficient refrigerant to satisfy load demand while simultaneously ensuring sufficient lubricating oil to satisfy the lubrication requirements of the compressor.

Description

RECEIVER ASSEMBLY AND HEAT PUMP SYSTEM HAVING THE SAME

TECHNICAL FIELD

[0001] The present invention relates to the field of air conditioning, and more particularly to an accumulator for a heat pump system.

BACKGROUND ART

[0002] At present, heat pump systems having both cooling and heating functions are widely used in various commercial and domestic applications such as hospitals, shopping malls, and homes. In practical application, heat pump system condensers typically employ coiled heat exchangers to achieve more substantial contact and heat transfer with air, whereas evaporators typically utilize plate heat exchangers for maximal heat exchange between a primary and secondary refrigerant (e.g. water). The working principle involves switching the heat exchange flow path in the heat pump system, so that in the cooling mode the coiled heat exchanger serves as a condenser and the plate heat exchanger serves as an evaporator, whereas in the heating mode, the coiled heat exchanger serves as an evaporator and the plate heat exchanger serves as a condenser, thereby enabling the plate heat exchanger to respectively perform the functions of cooling and heating. Since plate heat exchangers often have a much smaller volume than coiled heat exchangers, when the heat pump system is switched to the heating mode, less of the refrigerant flowing through the plate heat exchanger is needed for condensation heat transfer, and hence the surplus refrigerant needs to be temporarily stored in an accumulator. In the cooling mode, it flows out of the accumulator to once again participate in the working cycle.

[0003] An existing type of accumulator utilizes a dual pipe system, i.e. a separate inlet pipe and an outlet pipe are provided. Such an accumulator has a relatively high material cost and manufacturing cost. Another type of existing accumulator has a single pipe system, i.e. liquid inflow and outflow are accomplished using one pipe. However, when a single-pipe accumulator is used, it is prone to a phenomenon whereby lubricating oil entering the accumulator with the refrigerant is retained in and builds up in the accumulator, which affects the service life of the heat pump system by causing a loss of lubricating oil in the compressor. This in turn impacts on system reliability. SUMMARY OF THE UTILITY MODEL

[0004] It is an object of the present utility model to provide an accumulator that reduces the accumulation of lubricating oil.

[0005] Another object of the present utility model is to provide a heat pump system having an accumulator that reduces the accumulation of lubricating oil.

[0006] In order to achieve one object of the present invention, according to an aspect of the present invention there is provided an accumulator assembly, comprising: an accumulator tank body, wherein an inlet and outlet port is disposed at the bottom of the tank body and is flush therewith; and

a connecting pipe, having a first end connected to the inlet and outlet port, and a second end for connection to an air conditioning system.

[0007] In order to achieve the other object of the present invention, in accordance with another aspect of the present invention there is also provided a heat pump system, comprising: the accumulator assembly as described above, wherein the connecting pipe of the accumulator assembly is connected vertically downward to the heat pump system between the throttling member and the evaporator in the heat pump system cooling mode, and the bottom inlet and outlet port of the accumulator assembly is integrally mounted vertically downward in the heat pump system.

DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 is a schematic view of the accumulator of the present invention.

[0009] FIG. 2 is a partially enlarged schematic view of the accumulator of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Referring to FIGs. 1 and 2, one embodiment of an accumulator assembly in accordance with the present concept is illustrated. The accumulator assembly 100 comprises an accumulator tank body 110 and a connecting pipe 120 coupled thereto. Here, an inlet and outlet port 111 is provided at the bottom portion 110a of the accumulator tank body 110, and the key point is that the inlet and outlet port 111 is flush with the bottom portion 110a of the accumulator tank body 110. At the same time, a first end 120a of the connecting pipe 120 is connected to the inlet and outlet port 111, and a second end 120b thereof is used for connection to an air conditioning system. In certain scenarios, the air conditioning system is a heat pump system. Under this arrangement, since the inlet and outlet port is flush with the bottom of the accumulator tank body, in the case where all the refrigerant is needed for operation of the system, the refrigerant and lubricating oil accumulated in the accumulator tank body can be fully drained from the accumulator tank body, thus ensuring sufficient refrigerant to satisfy load demand while simultaneously ensuring sufficient lubricating oil to satisfy the lubrication requirements of the compressor. If the inlet and outlet port is placed higher than the bottom of the accumulator tank body, when the refrigerant is discharged from the accumulator tank body, a portion of the lubricating oil will accumulate in the height difference region between the inlet and outlet port and the bottom of the accumulator tank body, where the accumulated volume will depend on the volume of the height difference region, and this will affect the lubrication of the compressor and thus the reliability of the entire heat pump system.

[0011] According to the teachings of the foregoing solution for solving the problem of media accumulation in the accumulator, the solution can be refined and improved from various angles to obtain further optimization of performance or improvement in cost performance.

[0012] For example, the inlet and outlet port 111 can be disposed at the lowest point of the bottom portion 110a of the accumulator tank body 110, whereby the complete discharge of various fluid media in the accumulator tank body can be ensured to the utmost extent.

[0013] As another example, the accumulator tank body 110 may be provided with a level bottom portion 110a to facilitate manufacturing, in which case the inlet and outlet port 111 can be disposed at the center point of the bottom portion 110a of the accumulator tank body 110. Such an arrangement maximizes the distance of flow from each part of the bottom of the accumulator tank body to the inlet and outlet port, so that the amount of lubricant adhering to the bottom of the accumulator tank body due to its own viscosity is reduced.

[0014] Further, as another auxiliary improvement, the connecting pipe 120 may also be welded to the inlet and outlet port 111 to facilitate processing. It is also possible to provide an arcuate flow guiding surface at the inlet and outlet port 111 so that the flow resistance of the refrigerant in and out of the port is smaller. Moreover, the connecting pipe 120 can be configured as a round pipe, which is more versatile and easy to select.

[0015] In accordance with the foregoing conception of an accumulator, an embodiment of a heat pump system not shown in the drawings is also provided herein. This heat pump system has the basic components and connection methods of the conventional heat pump system, which will therefore not be elaborated herein. More critically, the heat pump system further comprises any one of the foregoing embodiments, wherein the second end 120b of the connecting pipe 120 of the accumulator assembly 100 is connected between the condenser and the evaporator of the heat pump system, and the connecting pipe of the accumulator assembly is integrally connected vertically downward to the heat pump system. [0016] Thus, the accumulator assembly in the foregoing embodiment can perform the functions in the heat pump system of temporarily storing and releasing the refrigerant and the lubricating oil flushed with the refrigerant, and of completely discharging the refrigerant and lubricating oil under high load conditions to stabilize the performance of the system.

[0017] As a more specific embodiment, the heat pump system further comprises a heat exchange circuit having a compressor exhaust port, a four-way valve assembly, a condenser, a throttling member, an accumulator assembly, an evaporator and a compressor suction port, sequentially connected via pipes; wherein, the four-way valve assembly is capable of switching the flow direction to enable a cooling mode and a heating mode; in the cooling mode, the refrigerant medium is circulated from the compressor exhaust port to the compressor suction port via the four-way valve assembly, condenser, throttling member, accumulator assembly, and evaporator; and in the heating mode, the refrigerant medium circulates from the compressor exhaust port to the compressor suction port via the four-way valve assembly, evaporator, accumulator assembly, throttling member, and condenser.

[0018] As a further embodiment, the condenser should have a larger volume than the evaporator, in which case, in the cooling mode, the connecting pipe 120 serves as a drain pipe, and a portion of the refrigerant flows out of the accumulator tank body 110; in the heating mode, the connecting pipe 120 serves as a liquid inlet pipe, and a portion of the refrigerant flows into the accumulator tank body 110.

[0019] In these more specifically configured heat pump systems, the accumulator assembly can likewise perform the functions of temporarily storing and releasing the refrigerant and the lubricating oil flushed with the refrigerant, and of completely discharging the refrigerant and lubricating under high load conditions to stabilize the system performance.

[0020] The working process will be exemplified herein with reference to the aforementioned embodiments of the heat pump system.

[0021] When the cooling mode is operated, the four-way valve assembly is reversed to connect the compressor exhaust port with the condenser and the compressor suction port with the evaporator. Now, high-pressure high-temperature refrigerant flows out from the compressor exhaust port and flows into the condenser through the four-way valve assembly, and the high-pressure medium-temperature refrigerant that flows out then heads to the throttling member to be throttled into low-pressure low-temperature refrigerant, which then flows through the accumulator assembly. Refrigerant which has undergone this process next flows into the evaporator to be cooled, and the low-pressure medium-temperature refrigerant that flows out flows back to the compressor suction port through the four-way valve assembly, thereby completing cooling mode operation.

[0022] When the heating mode is operated, the four-way valve assembly is reversed to connect the compressor exhaust port with the evaporator and the compressor suction port with the condenser. Now, the high-pressure high-temperature refrigerant flows out from the compressor exhaust port and flows into the evaporator through the four-way valve assembly, and then the high-pressure medium-temperature refrigerant that flows out passes through the accumulator assembly headed for the throttling member, where it is throttled into low-pressure low-temperature refrigerant, which then enters the evaporator to release heat. The low-pressure medium-temperature refrigerant that subsequently flows out flows back to the compressor suction port through the four-way valve assembly, thereby completing heating mode operation. Since the evaporator typically has a smaller volume than the condenser, this process generally does not require participation of all of the refrigerant; the refrigerant that is not involved in the operation will accumulate in the accumulator assembly and will flow out again as the mode switches.

[0023] It would be readily apparent that the accumulator assembly is not limited to a heat pump system having only a cooling and heating mode, and is equally applicable to a heat pump system further provided with three heat exchangers and a heat recovery and/or water heating mode, or other modifications. Further, the accumulator assembly is not limited to a heat pump system, and any system which requires different amounts of refrigerant in different situations and has a need for temporary storage of refrigerant may adopt the accumulator assembly according to the present concept. For example, some equipment manufacturers only provide condensing units that are installed outdoors, such that the accumulator as presently conceived could also be employed in situations where it is not possible to know the evaporator which may be configured indoors by the customer or the amount of refrigerant which may be provided in response to the length of tubing.

[0024] The above examples mainly illustrate the accumulator of the present utility model and the heat pump system provided with the same. Although only a few of the embodiments of the present utility model have been described, it should be appreciated by those skilled in the art that the present utility model may be embodied in many other forms without departing from the purport and scope of the utility model. Accordingly, the present embodiments are to be considered as illustrative and not restrictive, and the scope of the invention may encompass various modifications and substitutions.

Claims

1. An accumulator assembly, characterized in comprising:

an accumulator tank body, wherein an inlet and outlet port is disposed at the bottom of the tank body and is flush therewith; and

2. The accumulator assembly as recited in claim 1, characterized in that the inlet and outlet port is disposed at a lowest point of the bottom of the accumulator tank body.

3. The accumulator assembly as recited in claim 1, characterized in that the inlet and outlet port is disposed at a center point of the bottom of the accumulator tank body.

4. The accumulator assembly as recited in any one of claims 1 to 3, characterized in that the accumulator tank body has a level bottom.

5. The accumulator assembly as recited in any one of claims 1 to 3, characterized in that the connecting pipe is welded to the inlet and outlet port.

6. The accumulator assembly as recited in any one of claims 1 to 3, characterized in that the inlet and outlet port is provided with an arcuate flow guiding surface.

7. The accumulator assembly as recited in any one of claims 1 to 3, characterized in further comprising the connecting pipe being a round pipe.

8. A heat pump system, characterized in comprising an accumulator assembly, said accumulator assembly comprising: an accumulator tank body, wherein an inlet and outlet port is disposed at the bottom of the tank body and is flush therewith; and a connecting pipe, having a first end connected to the inlet and outlet port, and a second end connected downwardly to the heat pump system.

9. The heat pump system as recited in claim 8, characterized in further comprising a heat exchange circuit having a compressor exhaust port, a four-way valve assembly, a condenser, a throttling member, an accumulator assembly, an evaporator and a compressor suction port, sequentially connected via pipes;

wherein, the four-way valve assembly is capable of switching the flow direction to enable a cooling mode and a heating mode;

in the cooling mode, the refrigerant medium is circulated from the compressor exhaust port to the compressor suction port via the four-way valve assembly, condenser, throttling member, accumulator assembly, and evaporator; and/or in the heating mode, the refrigerant medium circulates from the compressor exhaust port to the compressor suction port via the four-way valve assembly, evaporator, accumulator assembly, throttling member, and condenser.

10. The heat pump system as recited in claim 9, characterized in that the condenser has a volume greater than that of the evaporator, wherein:

in the cooling mode, the connecting pipe serves as a drain pipe, and a portion of the refrigerant flows out of the accumulator tank body;

in the heating mode, the connecting pipe serves as a liquid inlet pipe, and a portion of the refrigerant flows into the accumulator tank body.