LOW AMBIENT OUTDOOR COIL RESTRICTOR PLATE FOR AIR CONDITIONER
A low ambient cooling system for a variable refrigerant flow heat pump includes an outdoor air conditioning unit and an indoor air conditioning unit. The outdoor air conditioning unit includes an outdoor heat exchanger with one or more valves that selectively control refrigerant flow through different sections of condenser coils during a low ambient cooling mode. During the low ambient cooling mode, the condenser coils of the outdoor heat exchanger include an active coil section through which refrigerant flows and an inactive coil section that is closed. An outdoor-coil restrictor plate with holes is attached to the active condenser coil in the outdoor air conditioning unit. The outdoor-coil restrictor plate restricts excessive heat release from the active coil section of the condenser coils in the outdoor heat exchanger during the low ambient cooling mode.
The subject matter described below relates generally to low ambient restrictor plate for an outdoor coil of an air-conditioning system. More particularly, the described subject matter relates to a low ambient restrictor plate that reduces the release of heat from condenser coils of an outdoor air conditioning unit during a cooling mode in low ambient conditions.
BACKGROUNDIn general, an air-conditioning system based on a heat pump design transports heat to, and from, an indoor air-conditioned space. Heat is transferred between the indoor space and the outdoor environment via an outdoor heat exchanger and an indoor heat exchanger that are connected through piping that circulate a heat medium (e.g., a refrigerant or water).
During a heating mode, the indoor unit provides heat to the indoor space. To do so, the outdoor unit absorbs heat from the outdoor ambient environment, transfers the absorbed heat to the refrigerant (e.g., by evaporating the refrigerant), circulates the refrigerant to the indoor unit where the indoor unit releases the heat to the indoor space (e.g., by condensing the refrigerant).
A heat pump essentially performs the reverse operation during a cooling mode. That is, the indoor unit absorbs heat from the indoor space (e.g., by evaporating the refrigerant), and the heat pump circulates the refrigerant to the outdoor unit where the outdoor unit releases the heat to the outdoor ambient environment (e.g., by condensing the refrigerant).
In some heat pumps, the heating mode and the cooling mode are performed seasonally. That is, the heating mode is performed during cold ambient temperatures and the cooling mode is performed during warm ambient temperatures. Traditional problems that exist for heat pumps may include how effectively heat is released to, or absorbed from, the ambient when a heating mode is performed during cold ambient temperatures and a cooling mode is performed during warm ambient temperatures. These problems are typically addressed by increasing heat absorption from cold ambient air or increasing heat release to warm ambient air.
However, certain heat pumps may also perform the cooling mode during cold ambient temperatures. Unlike traditional operations, performing a cooling mode during cold ambient temperatures presents unique problems. For example, the outdoor unit releases heat to the outdoor environment during a cooling mode by condensing the refrigerant. During warmer temperatures, heat pumps must essentially work against hotter outdoor temperatures to condense the refrigerant since heat must forcibly be released to a warm ambient.
In contrast, when an outdoor unit performs a cooling mode during cold ambient temperatures, the hotter outdoor temperature working against the condensing of the refrigerant is no longer an issue. Instead, a new problem may arise in that the cooler ambient temperature draws an excess amount of heat from the refrigerant as the outdoor unit condenses the refrigerant. This cooling mode during low ambient conditions may cause an uncontrolled drop in temperature and pressure beyond the predetermined temperature and pressure. During an uncontrolled drop in refrigerant temperature and pressure, the evaporator of the indoor units may freeze since the refrigerant has been overly cooled. As will be understood by one skilled in the art, these problems of performing a cooling mode in a low ambient environment become more dramatic during colder temperatures below freezing (e.g., below about 23° F. or −5° C.).
With these problems, general attempts to improve the capacity of a heat pump may exasperate the problems that arise during low ambient cooling. For example, approaches that increase heat release from the outdoor unit exasperate problems that occur during a cooling mode in cooler ambient temperatures, since it may cause excessive released from the condenser coil.
Attempts to address low ambient conditions may be focused on controlling the wind entering the outdoor unit. However, these approaches do not address the problems associated with uncontrolled release of heat from the outdoor coil itself. As discussed above, a major problem that occurs during a cooling mode in low ambient temperatures is uncontrolled release of heat from the coils of the outdoor heat exchanger. This uncontrolled release of heat may still occur even if wind is prevented from entering the outdoor unit due to the low ambient temperatures.
It would therefore be desirable to provide a outdoor coil restrictor plate that controls the release of heat from outdoor coils that are active during a cooling mode in low ambient conditions.
SUMMARYA low ambient cooling system is provided for a variable refrigerant flow heat pump, that includes the following: an outdoor air conditioning unit that includes a compressor, a fan, and a housing that includes an air inlet and an air outlet; an outdoor heat exchanger that is installed in the housing of the outdoor air conditioning unit and that includes one or more valves configured to selectively control refrigerant flow through different sections of condenser coils during a low ambient cooling mode, the condenser coils of the outdoor heat exchanger include an active coil section through which refrigerant flows during the low ambient cooling mode and inactive coil section that is closed during the low ambient cooling mode; and an active-outdoor-coil restrictor plate that includes an inner surface attached to the active coil section, an outer surface opposite to the inner surface, an edge that connects the outer surface to the inner surface, and holes that extend from the outer surface to the inner surface to reduce excessive heat release from the active coil section of the condenser coils in the outdoor heat exchanger during the low ambient cooling mode.
The low ambient cooling system may further include an indoor air conditioning unit. The indoor unit includes an evaporator in the low ambient cooling mode and that is connected to the outdoor air conditioning unit through piping and an expansion valve.
The low ambient cooling system may further include a wind guard attached to the housing of the outdoor air conditioning unit.
The low ambient cooling block system may further include a controller configured to control the valves of the of the outdoor heat exchanger to selectively control refrigerant flow through the active coil section and the inactive coil section of the outdoor heat exchanger during the low ambient cooling mode.
The controller may be configured to control the valves to open refrigerant flow through the active coil section of the outdoor heat exchanger and to open refrigerant flow through the inactive coil section of the outdoor heat exchanger during a high ambient cooling mode.
The active-outdoor-coil restrictor plate may be reversibly fastenable to the active coil section of the outdoor heat exchanger.
The holes of the active-outdoor-coil restrictor plate are circular or rectangular. The active-outdoor-coil restrictor plate includes one or more rows of the holes, one or more columns of the holes, or both rows and columns of holes. The holes of the active-outdoor-coil restrictor plate may be uncovered. The holes in the active-outdoor-coil restrictor plate may be cutouts.
A method of restricting heat release in an outdoor heat exchanger during low ambient cooling is provided, which includes the following: providing an outdoor unit configured to perform a low ambient cooling mode, the outdoor unit includes condenser coils having an active coil section and an inactive coil section in the low ambient cooling mode; attaching an inner surface of an active-outdoor-coil restrictor plate to the active coil section of the condenser coils of the outdoor unit, the active-outdoor-coil restrictor plate includes holes; and restricting, via the active-outdoor-coil restrictor plate, heat release in the active coil section of the outdoor unit during the low ambient coiling mode.
The method may also include detecting an outdoor ambient temperature; determining whether the outdoor ambient temperature is at, or below, a predetermined temperature; and controlling the outdoor unit to perform the low ambient cooling mode in response to determining that the predetermined temperature is at, or below, the predetermined temperature.
The holes of the active-outdoor-coil restrictor plate in the method may be uncovered.
The accompanying figures where like reference numerals refer to identical or functionally similar elements and which together with the detailed description below are incorporated in and form part of the specification, serve to further illustrate an exemplary embodiment and to explain various principles and advantages in accordance with the present disclosure.
The instant disclosure is provided to further explain in an enabling fashion the best modes of performing one or more embodiments. The disclosure is further offered to enhance an understanding and appreciation for the inventive principles and advantages thereof, rather than to limit in any manner the embodiments.
It is further understood that the use of relational terms, such as first and second, if any, are used to distinguish one from another entity, item, or action without necessarily requiring or implying any actual such relationship or order between such entities, items or actions. Some embodiments may include a plurality of processes or steps, which can be performed in any order unless expressly and necessarily limited to a particular order (i.e., processes or steps that are not so limited may be performed in any order).
The outdoor unit 100 includes a housing 102 having an inlet 104 and an outlet 106. Within the housing 102 of the outdoor unit 100, the outdoor unit 100 includes a compressor 2, a four-way valve 4 (e.g., a reversing valve), an outdoor heat exchanger 6 (e.g., an outdoor coil), an outdoor fan 8 (e.g., a blower fan), a controller 10, an outdoor temperature sensor 12, and an expansion valve 14 (e.g., a metering valve). The outdoor unit 100 also includes an inactive coil valve 16 and an active coil valve 18 that are respectively opened and closed during a low ambient cooling mode, which is discussed further below. The inactive coil valve 16 and the active coil valve 18 selectively controlled (by, e.g., the controller 10) to control the flow of refrigerant through the different sections of the outdoor heat exchanger 6.
The indoor unit 200 includes a housing 202 having an inlet 204 and an outlet 206. Within the housing 202 of the indoor unit 200, the indoor unit 200 includes an indoor heat exchanger 20 (e.g., an indoor coil) and an indoor fan 22 (e.g., a blower fan).
The controller 10 is operatively connected to the components within the outdoor unit 100 and the indoor unit 200. For example,
The controller 10 may be connected to the components of the variable refrigerant flow heat pump 1 through wired connections, wireless connections, or both. For ease of reference and illustration, the connections of the controller 10 are only explicitly shown in
As shown in the cooling mode in
In
On the other hand,
During low ambient temperatures, the outdoor heat exchanger 6 may release an excessive amount of heat while condensing the refrigerant. When an excess amount of heat is released from the outdoor heat exchanger 6, the refrigerant becomes overly cooled. Left uncontrolled, this may cause the refrigerant in the indoor heat exchanger 20 operating as an evaporator to freeze.
Unlike the cooling mode in
During the low ambient cooling mode, the surface area of the coils in the outdoor heat exchanger 6 is reduced, since the cooler ambient temperature will facilitate heat release from the condenser coils of the outdoor heat exchanger 6.
While the variable refrigerant flow heat pump 1 can control the flow of refrigerant through certain sections of the outdoor heat exchanger 6 through operation of the inactive coil valve 16 and the active coil valve 18, this control alone may be insufficient to prevent the outdoor heat exchanger 6 from releasing an excessive amount of heat to the ambient environment.
In order to restrict the release of heat from the remaining active coil sections of the outdoor heat exchanger 6 that remain open to refrigerant flow during a low ambient cooling mode, the variable refrigerant flow heat pump 1 includes a restrictor plate 30.
During the low ambient cooling mode, the outdoor heat exchanger 6 includes a first inactive coil section 24, a second inactive coil section 26, and an active coil section 28.
In
As shown in
This configuration allows the restrictor plate 30 to restrict the heat release from the active condenser coil 40 by allowing heat release from the exposed portions 42 of the active condenser coil 40 and restricting heat release from the unexposed portions 44 of the active condenser coil 40.
In combination with the variable refrigerant flow heat pump 1 and the corresponding control of the first inactive coil section 24, the second inactive coil section 26, and the active coil section, these features of the restrictor plate 30 provide greater control of the release of heat during low ambient cooling.
For example, the variable refrigerant flow heat pump 1 may be limited to reducing the flow of refrigerant to one predetermined section, such as the active coil section 28. However, the restrictor plate 30 provides further restriction, and control, of the release of heat from the active condenser coil 40 beyond the limitations of the control of the variable refrigerant flow heat pump 1 alone, such as through valve control.
Consequently, the combination of the variable refrigerant flow heat pump 1 and the restrictor plate 30 on the active coil section 28 allows greater restriction of the amount of heat released from the outdoor heat exchanger 6 during the low ambient cooling mode of
As discussed above and shown in
For example,
For example,
Note that in
Without the restrictor plate 30, the active condenser coil 40 would be entirely exposed to the ambient environment. During low ambient cooling, this provides problems since an excess amount of available heat 60 will be released to the ambient environment through ambient heat exchange 64.
Furthermore, even though the variable refrigerant flow heat pump 1 can control which section of the outdoor heat exchanger 6 is active, the variable refrigerant flow heat pump 1 may be limited by, e.g., the control of refrigerant flow through the coils through inactive coil valve 16 and the active coil valve 18. During a low ambient cooling mode, the control of the inactive coil valve 16 and the active coil valve 18 may be inadequate to prevent excessive release of available heat 60 during low ambient temperatures.
On the other hand, the restrictor plate 30 in combination with the variable refrigerant flow heat pump 1 allows a greater control of the release of available heat 60 from active condenser coil 40 of outdoor heat exchanger 6. The restrictor plate 30 provides these features without a costly redesign of the configuration of the outdoor heat exchanger 6, the controller 10, and/or the variable refrigerant flow heat pump 1 to accommodate low ambient cooling conditions.
The restrictor plate 30 also utilizes a relatively small amount of space in the outdoor unit 100, since the restrictor plate 30 is flat. This allows the restrictor plate 30 to be installed without modifying either the components of the outdoor heat exchanger 6 or increase the area of space that the outdoor unit 100 occupies. The area that the space the outdoor unit 100 occupies (e.g., the footprint) is significant in residential and commercial settings.
The outdoor heat exchanger 6 includes an active coil section 28 with a restrictor plate 30. As shown in
The outdoor unit 100 may include one or more wind guards 70 to block wind from entering the housing 102 of the outdoor unit 100. The wind guards 70 may be used in combination with the restrictor plate 30, as shown in
In addition, the outdoor heat exchanger 6 is depicted with a first inactive coil section 24 and a second inactive coil section 26. However, the number of inactive coil sections of the outdoor heat exchanger 6 is not particularly limited. For example, the outdoor heat exchanger 6 may include only two coil sections, which may correspond to the first inactive coil section 24 and the active coil section 28. The active coil section 28 is smaller than the inactive coil (e.g., one or both of the first inactive coil section 24 and the second inactive coil section 26).
Step 1404 in the method 1400 is to attach a restrictor plate 30 to the active coil section 28 of the outdoor heat exchanger 6 in the outdoor unit 100. The restrictor plate 30 may be reversibly attached to the active coil section 28 via fasteners (e.g., screws, rivets, nuts, and/or bolts). The fasteners may extend through the outer surface of the restrictor plate 30. The restrictor plate 30 restricts the release of available heat 60 in the active coil section 28 during a low ambient cooling mode.
Step 1406 of the method 1400 in
In Step 1408, the controller 10 determines whether the outdoor temperature is equal to, or less than, a predetermined temperature (e.g., 23° F. or −5° C.). The determination in Step 1408 may be made when the variable refrigerant flow heat pump 1 performs a cooling operation or a low ambient cooling operation.
If the controller 10 determines that the outdoor temperature is greater than the predetermined temperature, the controller 10 controls the variable refrigerant flow heat pump 1 to perform a high ambient cooling mode. The high ambient cooling mode can be seen in
Note that the terms active and inactive refer to the refrigerant flow during low ambient cooling mode. Thus, refrigerant flows through the first inactive coil section 24 and the second inactive coil section 26 when the inactive coil valve 16 is opened in, e.g., the high ambient cooling mode, as shown in
During the high ambient cooling mode, which can be seen in
On the other hand, in Step 1408 in the method 1400 of
In the low ambient cooling mode, the controller 10 closes the inactive coil valve 16 and opens the active coil valve 18. The controller 10 may operate the four-way valve 4 to switch the flow of refrigerant between the outdoor unit 100 and the indoor unit 200. In the low ambient cooling mode, the indoor unit 200 absorbs heat from the indoor space and release heat to the ambient environment through the active coil section 28 of the outdoor heat exchanger 6 in the outdoor unit 100.
In Step 1414 of the method 1400 in
Although not shown explicitly in
The components of the variable refrigerant flow heat pump 1 and system described above are example components. As will be understood by one skilled in the art, the variable refrigerant flow heat pump 1 may include one or more of each of the components. For example, the variable refrigerant flow heat pump 1 may include more than one indoor unit 200, more than one outdoor unit 100, more than one valve, and more than one sensor. There may be more than one of the components described above in the indoor unit 200 and the outdoor unit 100. For example, the outdoor unit 100 may include more than one compressor 2. The system may also include more than one controller 10.
The controller 10 discussed above may include one or more processors and memory. The controller 10 may be, or include, e.g., a microcontroller, a microcomputer, or a digital signal processor. The memory can include a static memory (e.g., ROM, PROM, EPROM, masked), dynamic memory (e.g., RAM, SRAM, DRAM), and/or a hybrid memory (e.g., NVRAM, EEPROM, Flash) that holds information used by the controller 10. This can include one or more programs for operating the components of the variable refrigerant flow heat pump 1, data used by the controller 10 (e.g., predetermined temperatures), and/or technical information used by the controller 10. In various embodiments, the memory of the controller 10 may include a flash drive, a solid-state drive, a magnetic or optical drive, or any suitable memory device.
This disclosure is intended to explain how to fashion and use various embodiments in accordance with, not limit. the true, intended, and fair scope and spirit thereof. The foregoing description is not intended to be exhaustive, or limited to, the precise form disclosed. Modifications or variations are possible in light of the above teachings. The embodiments above are chosen and described to provide illustration of the principles as practical applications, and to enable one of ordinary skill in the art to utilize the various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the disclosure as determined by the appended claims, as may be amended during the pendency of this application for patent, and all equivalents thereof, when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.
Claims
1. A low ambient cooling system for a variable refrigerant flow heat pump, comprising:
- an outdoor air conditioning unit that includes a compressor, a fan, and a housing that includes an air inlet and an air outlet;
- an outdoor heat exchanger that is installed in the housing of the outdoor air conditioning unit and that includes one or more valves configured to selectively control refrigerant flow through different sections of condenser coils during a low ambient cooling mode, the condenser coils of the outdoor heat exchanger include an active coil section through which refrigerant flows during the low ambient cooling mode and inactive coil section that is closed during the low ambient cooling mode; and
- an active-outdoor-coil restrictor plate that includes an inner surface attached to the active coil section, an outer surface opposite to the inner surface, an edge that connects the outer surface to the inner surface, and holes that extend from the outer surface to the inner surface to reduce excessive heat release from the active coil section of the condenser coils in the outdoor heat exchanger during the low ambient cooling mode.
2. The low ambient cooling system according to claim 1, further comprising
- an indoor air conditioning unit that includes an evaporator in the low ambient cooling mode and that is connected to the outdoor air conditioning unit through piping and an expansion valve.
3. The low ambient cooling system according to claim 1, further comprising a wind guard attached to the housing of the outdoor air conditioning unit.
4. The low ambient cooling system according to claim 1, further comprising
- a controller configured to control the valves of the of the outdoor heat exchanger to selectively control refrigerant flow through the active coil section and the inactive coil section of the outdoor heat exchanger during the low ambient cooling mode.
5. The low ambient cooling system according to claim 4, wherein
- the controller is configured to control the valves to open refrigerant flow through the active coil section of the outdoor heat exchanger and to open refrigerant flow through the inactive coil section of the outdoor heat exchanger during a high ambient cooling mode.
6. The low ambient cooling system according to claim 1, wherein
- the active-outdoor-coil restrictor plate is reversibly fastenable to the active coil section of the outdoor heat exchanger.
7. The low ambient cooling system according to claim 1, wherein
- the holes of the active-outdoor-coil restrictor plate are circular or rectangular.
8. The low ambient cooling system according to claim 1, wherein
- the active-outdoor-coil restrictor plate includes one or more rows of the holes.
9. The low ambient cooling system according to claim 8, wherein
- the active-outdoor-coil restrictor plate includes one or more columns of the holes.
10. The low ambient cooling system according to claim 1, wherein the active-outdoor-coil restrictor plate includes one or more columns of the holes.
11. The low ambient cooling system according to claim 1, wherein
- the holes of the active-outdoor-coil restrictor plate are uncovered.
12. The low ambient cooling system according to claim 1, wherein
- the holes in the active-outdoor-coil restrictor plate are cutouts.
13. A method of restricting heat release in an outdoor heat exchanger during low ambient cooling, comprising:
- providing an outdoor unit configured to perform a low ambient cooling mode, the outdoor unit includes condenser coils having an active coil section and an inactive coil section in the low ambient cooling mode;
- attaching an inner surface of an active-outdoor-coil restrictor plate to the active coil section of the condenser coils of the outdoor unit, the active-outdoor-coil restrictor plate includes holes; and
- restricting, via the active-outdoor-coil restrictor plate, heat release in the active coil section of the outdoor unit during the low ambient coiling mode.
14. The method according to claim 13, further comprising
- detecting an outdoor ambient temperature,
- determining whether the outdoor ambient temperature is at, or below, a predetermined temperature; and
- controlling the outdoor unit to perform the low ambient cooling mode in response to determining that the predetermined temperature is at, or below, the predetermined temperature.
15. The method according to claim 13, wherein
- the holes of the active-outdoor-coil restrictor plate are uncovered.
Type: Application
Filed: Oct 8, 2019
Publication Date: Apr 8, 2021
Inventors: Joseph Paul BUSH (Lawrenceville, GA), Allen BARBELY (Auburn, GA)
Application Number: 16/595,671