WO2021050625A1

WO2021050625A1 - Air conditioning system and method of operating the same

Info

Publication number: WO2021050625A1
Application number: PCT/US2020/050045
Authority: WO
Inventors: Richard G. Lord
Original assignee: Carrier Corporation
Priority date: 2019-09-11
Filing date: 2020-09-10
Publication date: 2021-03-18
Also published as: US20220196271A1

Abstract

An air conditioning system includes an indoor unit located in or connected to a conditioned space, and an outdoor unit located outdoors at an exterior of the conditioned space. An input pathway operably connects the outdoor unit to the indoor unit and is configured to deliver a flow of liquid refrigerant from the outdoor unit to the indoor unit during operation of the air conditioning system. A return pathway operably connects the outdoor unit to the indoor unit and configured to deliver a flow of vapor refrigerant from the indoor unit to the outdoor unit. One or more high flow fittings are located along each of the input pathway and the return pathway, and are configured to automatically actuate from an open position to a closed position in response to a flow rate of refrigerant through the high flow fitting exceeding a preselected threshold.

Description

AIR CONDITIONING SYSTEM AND METHOD OF OPERATING THE SAME

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of US Application No. 62/898,879, filed on September 11, 2019, which is incorporated herein by reference in its entirety.

BACKGROUND

[0001] Exemplary embodiments pertain to moderate-to-low global warming potential (GWP) value refrigerant leak detection and mitigation.

[0002] Air conditioning systems for residential or commercial spaces or buildings typically include an indoor unit or section of a packaged unit and an outdoor unit or section of a packaged unit. The outdoor unit circulates a flow of refrigerant to an indoor unit, which is utilized to cool and dehumidify an airflow via thermal interaction with the refrigerant, and thus condition a selected space.

[0003] This refrigerant, historically, has been provided as a fluid with a high global warming potential (GWP) value such as R134A or R410A. Thus, although the refrigerants that have been used previously are effective coolants, the negative effect they can have on the environment has led to regulatory requirements to transition to refrigerants which have moderate-to-low GWP values.

[0004] Moderate-to-low GWP value refrigerants (i.e., A2L) can be mildly flammable, however, and thus their use in air conditioning systems can present a fire risk that needs to be addressed. It is desired to reduce the exposure of the conditioned space to such refrigerants. In particular, to the extent that refrigerant leaks are possible in air conditioning systems, the use of moderate-to-low GWP value refrigerants makes refrigerant leak detection and mitigation mandatory especially for indoor units of ducted residential heating, ventilation and air conditioning (HVAC) products and other similar systems.

BRIEF DESCRIPTION

[0005] In one embodiment, an air conditioning system includes an indoor unit located in or connected to a conditioned space, and an outdoor unit located outdoors at an exterior of the conditioned space. An input pathway operably connects the outdoor unit to the indoor unit and is configured to deliver a flow of liquid refrigerant from the outdoor unit to the indoor unit during operation of the air conditioning system. A return pathway operably connects the outdoor unit to the indoor unit and configured to deliver a flow of vapor refrigerant from the indoor unit to the outdoor unit. One or more high flow fittings are located along each of the input pathway and the return pathway, and are configured to automatically actuate from an open position to a closed position in response to a flow rate of refrigerant through the high flow fitting exceeding a preselected threshold.

[0006] Additionally or alternatively, in this or other embodiments a high flow fitting of the one or more high flow fittings is located between a condenser of the outdoor unit and an expansion valve of the indoor unit.

[0007] Additionally or alternatively, in this or other embodiments a high flow fitting of the one or more high flow fittings is located between an evaporator of the indoor unit and a compressor of the outdoor unit.

[0008] Additionally or alternatively, in this or other embodiments the one or more high flow fittings are located outdoors at the exterior of the conditioned space.

[0009] Additionally or alternatively, in this or other embodiments the refrigerant is one rated by the American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) as A2L or A3.

[0010] Additionally or alternatively, in this or other embodiments the automatic actuation of the high flow fittings is in response to a leak of refrigerant from the indoor unit.

[0011] Additionally or alternatively, in this or other embodiments the one or more high flow fittings each latch in the closed position once actuated via a latching mechanism.

[0012] Additionally or alternatively, in this or other embodiments the latching mechanism is one of a magnetic or mechanical latching mechanism.

[0013] Additionally or alternatively, in this or other embodiments a high flow fitting of the one or more high flow fittings is located between an expansion valve of the outdoor unit and an evaporator of the indoor unit.

[0014] In another embodiment, a method of operating an air conditioning system includes providing one or more high flow fittings on a refrigerant flow line between an indoor unit and an outdoor unit of the air conditioning system, and automatically actuating by high flow the high flow fittings from an open position to a closed position in response to a mass flow of refrigerant across the high flow fittings exceeding a threshold.

[0015] Additionally or alternatively, in this or other embodiments the one or more high flow fittings are latched at the closed position.

[0016] Additionally or alternatively, in this or other embodiments the one or more high flow fittings are latched via one of a magnetic or mechanical latching mechanism.

[0017] Additionally or alternatively, in this or other embodiments the one or more high flow fittings are reset to the opened position.

[0018] Additionally or alternatively, in this or other embodiments the automatic actuation of the one or more high flow fittings is in response to a leak of refrigerant from the indoor unit.

[0019] Additionally or alternatively, in this or other embodiments a high flow fitting of the one or more high flow fittings is located between a condenser of the outdoor unit and an expansion valve of the indoor unit.

[0020] Additionally or alternatively, in this or other embodiments a high flow fitting of the one or more high flow fittings is located between an evaporator of the indoor unit and a compressor of the outdoor unit.

[0021] Additionally or alternatively, in this or other embodiments the one or more high flow fittings are provided outdoors at an exterior of a conditioned space.

[0022] In yet another embodiment, air conditioning system includes an indoor unit located at a conditioned space. The indoor unit includes a fan coil unit, and an expansion valve fluidly coupled to the fan coil unit. An outdoor unit is located outdoors at an exterior of the conditioned space. The outdoor unit includes a compressor and a condenser fluidly coupled to the compressor. An input pathway operably connects the condenser to the expansion valve and is configured to deliver a flow of liquid refrigerant from the condenser to the expansion valve during operation of the air conditioning system. A return pathway operably connects the fan coil unit to the compressor, and is configured to deliver a flow of vapor refrigerant from fan coil unit to the compressor. One or more high flow fittings are located along each of the input pathway and the return pathway. Each high flow fitting is configured to automatically actuate from an open position to a closed position in response to a flow rate of refrigerant through the high flow fitting exceeding a preselected threshold, the flow rate exceeding the threshold due to a leak of refrigerant from the indoor unit.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike:

[0024] FIG. 1 is a schematic illustration of an embodiment of an air conditioning system;

[0025] FIG. 2 is a schematic illustration of an embodiment of a fan coil unit;

[0026] FIG. 3 is a partial cross-sectional view of an embodiment of a high flow fitting; and [0027] FIG. 4 is a schematic illustration of a method of operating an air conditioning system.

DETAILED DESCRIPTION

[0028] 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.

[0029] Referring to FIG. 1, illustrated is an embodiment of an air conditioning system 10. The air conditioning system 10 includes and indoor unit/section 12 used to cool a building 14 or other conditioned space, such as a container or refrigerated truck. An outdoor unit/section 16 is fluidly connected to the indoor unit 12 and is located outdoors, at an exterior of the building 14 or conditioned space.

[0030] The outdoor unit 16 includes a compressor 18 and a condenser 20 in a serial arrangement with an expansion device 22 and an evaporator 24 of the indoor unit 12. The indoor unit 12 and outdoor unit 16 define a vapor compression cycle in which refrigerant 26 flows as indicated by the arrow. The compressor 18 receives refrigerant vapor from the evaporator 24 and compresses it to a higher temperature and pressure, with the relatively hot vapor then passing to the condenser 20 where it is cooled and condensed to a liquid state by a heat exchange relationship with a cooling medium (not shown) such as air. The liquid refrigerant 26 then passes from the condenser 20 to an expansion device 22, wherein the refrigerant 26 is expanded to a low temperature two-phase liquid/vapor state as it passes to the evaporator 24. At the evaporator 24 a flow of relatively warm return air 28 is urged across the evaporator 24 by, for example, an evaporator fan 30. The return air 28 is cooled via thermal energy exchange with the refrigerant 26 flowing through the evaporator 24, and is flowed into the conditioned space 14 as supply air 32. The low pressure refrigerant vapor then returns to the compressor 18 where the cycle is repeated.

[0031] The indoor unit 12 is operably connected to the outdoor unit 16 via two refrigerant pathways, including an input pathway 34 extending from the condenser 20 to the expansion device 22 to deliver liquid refrigerant 26 from the condenser 20 to the expansion device 24, and a return pathway 36 extending from the evaporator 24 to the compressor 18 to deliver vapor refrigerant 26 from the evaporator 24 to the compressor 18. It is to be appreciated that this arrangement is merely exemplary, and that in other embodiments other arrangements may be utilized.

[0032] Referring again to FIG. 1, additionally in some embodiments, a pump 38 is located along the input pathway 34 to urge the liquid refrigerant 26 to the indoor unit 12. Referring now to FIG. 2, the evaporator 24 and the evaporator fan 30 may comprise a fan coil unit (FCU) disposed in an FCU housing 40. Return air 28 is admitted to the FCU housing 40 via a housing inlet 42, urged across the evaporator 24 by the evaporator fan 30, and flowed out of the FCU housing 40 into the conditioned space 14 via a housing outlet 44 as supply air 32.

[0033] The refrigerant 26 is typically one rated by the and American Society of Heating Refrigeration and Air Conditioning Engineers ASHRAE 34 Standard as A2L or A3, with an example of an A2L rated refrigerant 26 being R-454B or R32.

[0034] Referring again to FIG. 1, one or more high flow fittings 46 are positioned along the input pathway 34 and/or the return pathway 36. In one embodiment, the high flow fittings 46 are located outdoors, at the exterior of the building or conditioned space 14. The high flow fittings 46 are open during normal operation, and are configured to close in the event of a refrigerant leak in the indoor portion 12 to reduce the occurrence of refrigerant leakage into the conditioned space 14. When a significant refrigerant leak occurs, a flow rate of refrigerant across the high flow fittings 46 increases, and when the flow rate exceeds a preselected threshold, a flow rate that the high flow fitting may be calibrated for, the high flow fitting 46 automatically actuates from an open to a closed position as a reaction to the flow rate exceeding the threshold, thereby stopping the flow of refrigerant through the high flow fittings 46 and thereby stopping the flow of refrigerant along the input pathway 34 and/or the return pathway 36 to and through the indoor portion 12. Stoppage of the refrigerant flow into and through the indoor portion 12 reduces leakage of potentially hazardous refrigerant material into the conditioned space 14. In some embodiments, the high flow fitting 46 will actuate from the open position to the closed position at a threshold flow rate that is in the range of 10% to 30% greater than a maximum flow rate of non-leak operation of the air conditioning system 10.

[0035] Referring to the exemplary high flow fitting 46 of FIG. 3, the high flow fitting 46 is configured with a latching mechanism 48, for example a magnetic latching mechanism 48 such as shown, in which the high flow fitting 46 latches in the closed position once actuated from the open position to the closed position via the flow rate of the refrigerant exceeding the threshold. Once latched in the closed positon, therefore, the high flow fitting 46 may only be reset to the open position by intervention of an operator or service technician, for example. While a magnetic latching mechanism 48 is illustrated in FIG. 3, other types of latching mechanisms 48, such as a mechanical or electromagnetic latching mechanism 48 may be utilized.

[0036] While in the embodiment of FIG. 1, high flow fittings 46 are located at both the input pathway 34 and/or the return pathway 36, it is to be appreciated that in other embodiments a single high flow fitting 46 located at, for example, the input pathway 34 may be used.

[0037] Referring to FIG. 4, shown is a schematic illustration of a method 100 of operating an air conditioning system 10 is illustrated. In block 102, one or more high flow fittings 46 are provided on a refrigerant flow line between an indoor unit 12 and an outdoor unit 16 of the air conditioning system 10. In the event of a refrigerant leak in the indoor unit 12, the one or more high flow fittings 46 automatically actuate from an open position to a closed position at block 104 in response to an increase in mass flow of refrigerant across the high flow fittings 46 due to the leak. At block 106 the high flow fittings 46 latch at the closed position. The leak is repaired or otherwise addressed at block 108, after which the high flow fittings 46 may be reset to the open position at block 110. At block 112, once the high flow fittings 46 have been reset, operation of the air conditioning system 10 is restarted.

[0038] The air conditioning system 10 disclosed therein including the high flow fittings 46 provides added protection for air conditioning systems 10 utilizing mildly flammable low GWP refrigerants in reducing leakage of the refrigerant into the conditioned space 14 in the event of a catastrophic leak from the indoor unit 12 of the air conditioning system 10.

[0039] 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.

[0040] 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.

[0041] 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.

Claims

What is claimed is:

1. An air conditioning system, comprising: an indoor unit located in the or connected to a conditioned space ; an outdoor unit located outdoors at an exterior of the conditioned space; an input pathway operably connecting the outdoor unit to the indoor unit and configured to deliver a flow of liquid refrigerant from the outdoor unit to the indoor unit during operation of the air conditioning system; a return pathway operably connecting the outdoor unit to the indoor unit and configured to deliver a flow of vapor refrigerant from the indoor unit to the outdoor unit; and one or more high flow fittings disposed along each of the input pathway and the return pathway configured to automatically actuate from an open position to a closed position in response to a flow rate of refrigerant through the high flow fitting exceeding a preselected threshold.

2. The air conditioning system of claim 1, wherein a high flow fitting of the one or more high flow fittings is disposed between a condenser of the outdoor unit and an expansion valve of the indoor unit.

3. The air conditioning system of claim 1, wherein a high flow fitting of the one or more high flow fittings is disposed between an evaporator of the indoor unit and a compressor of the outdoor unit.

4. The air conditioning system of claim 1, wherein the one or more high flow fittings are disposed outdoors at the exterior of the conditioned space.

5. The air conditioning of claim 1, wherein the refrigerant is one rated by the American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) as A2L or A3.

6. The air conditioning system of claim 1, wherein the automatic actuation of the high flow fittings is in response to a leak of refrigerant from the indoor unit.

7. The air conditioning system of claim 1, wherein the one or more high flow fittings each latch in the closed position once actuated via a latching mechanism.

8. The air conditioning system of claim 7, wherein the latching mechanism is one of a magnetic or mechanical latching mechanism.

9. The air conditioning system of claim 1, wherein a high flow fitting of the one or more high flow fittings is disposed between an expansion valve of the outdoor unit and an evaporator of the indoor unit.

10. A method of operating an air conditioning system, comprising: providing one or more high flow fittings on a refrigerant flow line between an indoor unit and an outdoor unit of the air conditioning system; and automatically actuating by high flow the high flow fittings from an open position to a closed position in response to a mass flow of refrigerant across the high flow fittings exceeding a threshold.

11. The method of claim 10, further comprising latching the one or more high flow fittings at the closed position.

12. The method of claim 11, further comprising latching the one or more high flow fittings via one of a magnetic or mechanical latching mechanism.

13. The method of claim 10, further comprising resetting the one or more high flow fittings to the opened position.

14. The method of claim 10, wherein the automatic actuation of the one or more high flow fittings is in response to a leak of refrigerant from the indoor unit.

15. The method of claim 10, further comprising providing a high flow fitting of the one or more high flow fittings between a condenser of the outdoor unit and an expansion valve of the indoor unit.

16. The method of claim 10, further comprising providing a high flow fitting of the one or more high flow fittings between an evaporator of the indoor unit and a compressor of the outdoor unit.

17. The method of claim 10, further comprising providing the one or more high flow fittings outdoors at an exterior of a conditioned space.

18. An air conditioning system, comprising: an indoor unit located at a conditioned space, the indoor unit including: a heat exchanger; and an expansion valve fluidly coupled to the heat exchanger; an outdoor unit located outdoors at an exterior of the conditioned space, the outdoor unit including: a compressor; and a condenser fluidly coupled to the compressor; an input pathway operably connecting the condenser to the expansion valve and configured to deliver a flow of liquid refrigerant from the condenser to the expansion valve during operation of the air conditioning system; a return pathway operably connecting the heat exchanger to the compressor, configured to deliver a flow of vapor refrigerant from fan coil unit to the compressor; and one or more high flow fittings disposed along each of the input pathway and the return pathway, each high flow fitting configured to automatically actuate from an open position to a closed position in response to a flow rate of refrigerant through the high flow fitting exceeding a preselected threshold, the flow rate exceeding the threshold due to a leak of refrigerant from the indoor unit.