Outdoor refrigeration system with auxiliary heating feature

Abstract

Disclosed and described is an outdoor refrigeration system for a walk-in unit or conditioned space using an auxiliary heating feature to maintain a consistent temperature range. In an example, the outdoor refrigeration system includes a conditioned space unit, where the conditioned space unit is positioned at least partially in an ambient environment, a heating circuit coupled to a controller, where the heating circuit includes at least one heating element, and a refrigeration circuit coupled to the controller. In an example, the outdoor refrigeration system is configured to maintain a set temperature range in the conditioned space unit when an ambient temperature of the ambient environment is below a freezing point of water at a fixed altitude or a barometric pressure range.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority to U.S. Provisional Patent Application No. 63 / 549,284, filed Feb. 2, 2024, the entire contents of which application are incorporated by reference in their entirety.TECHNOLOGICAL FIELD

[0002] Example embodiments of the present disclosure relate generally to refrigeration systems and, more particularly, to outdoor refrigeration systems for walk-in units or conditioned spaces.BACKGROUND

[0003] In conventional refrigeration systems, such as conventional walk-in foodservice cooler applications, baseboard heaters or other standalone heating devices with integrated controls have traditionally been used to maintain internal temperatures above the freezing point of water when the ambient (e.g., outdoor) temperature drops below freezing so as to prevent food spoilage by freezing. Through applied effort, ingenuity, and innovation, many of the problems associated with these conventional refrigeration systems have been solved by developing solutions that are included in embodiments of the present disclosure, many examples of which are described in detail herein.BRIEF SUMMARY

[0004] The following presents a simplified summary of one or more examples of the disclosure in order to provide a basic understanding of such examples. This summary is not an extensive overview of all contemplated examples and is intended to neither identify key or critical elements of all examples, nor delineate the scope of any or all examples. Its sole purpose is to present some concepts of one or more examples in a simplified form as a prelude to the more detailed description that is presented later.

[0005] In some examples, a refrigeration system is provided. The refrigeration system includes: a conditioned space unit, the conditioned space unit being positioned at least partially in an ambient environment; a heating circuit communicably coupled to a controller, where the heating circuit comprises at least one heating element; and a refrigeration circuit communicably coupled to the controller. In one aspect, the refrigeration system is configured to maintain a set temperature range in the conditioned space unit when an ambient temperature of the ambient environment is below a freezing point of water at a fixed altitude or a barometric pressure range.

[0006] In some aspects, alone or in combination with any of the previous aspects, the refrigeration circuit includes: a compressor operably coupled to the refrigeration circuit; a condenser including a condenser input and a condenser output; and an evaporator including an evaporator input and an evaporator output, where the evaporator input is communicably coupled to the condenser output and the evaporator output is communicably coupled to the condenser input.

[0007] In some aspects, alone or in combination with any of the previous aspects, the conditioned space unit is entirely located in the ambient environment. In one aspect, alone or in combination with any of the previous aspects, at least a portion of the conditioned space unit is physically attached to a structure and a remainder of the conditioned space unit is located in the ambient environment.

[0008] In some aspects, alone or in combination with any of the previous aspects, the at least one heating element is adjacent to a fan, where the fan is configured to direct a flow of air into the conditioned space unit. In one aspect, alone or in combination with any of the previous aspects, the fan and the at least one heating element are adjacent to the evaporator.

[0009] In some aspects, alone or in combination with any of the previous aspects, the refrigeration system further includes a temperature measuring device. In one aspect, alone or in combination with any of the previous aspects, the temperature measuring device includes a temperature probe. In one aspect, alone or in combination with any of the previous aspects, the temperature measuring device is configured to measure the temperature of the conditioned space unit. In one aspect, alone or in combination with any of the previous aspects, the temperature measuring device is operably coupled to the controller.

[0010] In some aspects, alone or in combination with any of the previous aspects, the controller is configured to activate the at least one heating element based on determining that a temperature of the conditioned space unit is below a minimum value of the set temperature range. In one aspect, alone or in combination with any of the previous aspects, the controller is configured to activate the refrigeration circuit based on determining that a temperature of a conditioned space is above a maximum value of the set temperature range.

[0011] In some aspects, alone or in combination with any of the previous aspects, the at least one heating element includes a resistance heater. In one aspect, alone or in combination with any of the previous aspects, the controller includes an ignition-proof material. In one aspect, alone or in combination with any of the previous aspects, the heating circuit includes at least one ignition-proof component.

[0012] In some aspects, alone or in combination with any of the previous aspects, the refrigeration system further includes a circulating fan. In one aspect, alone or in combination with any of the previous aspects, the circulating fan is communicably coupled to the heating circuit and the refrigeration circuit. In one aspect, alone or in combination with any of the previous aspects, the circulating fan is configured to direct heated air away from the at least one heating element and into the conditioned space unit.

[0013] In some aspects, alone or in combination with any of the previous aspects, one or more components of the refrigeration system are installed in an outdoor environment. In one aspect, alone or in combination with any of the previous aspects, one or more components are exposed to an ambient environment.

[0014] In some aspects, alone or in combination with any of the previous aspects, the at least one heating element is positioned within the conditioned space unit. In one aspect, alone or in combination with any of the previous aspects, the ambient temperature is at or below a freezing point of water.

[0015] In some aspects, alone or in combination with any of the previous aspects, the refrigerant includes an A3 refrigerant. In one aspect, alone or in combination with any of the previous aspects, the refrigeration circuit further includes a maximum charge of 5.3 ounces of the A3 refrigerant per compressor. In one aspect, alone or in combination with any of the previous aspects, the refrigerant includes propane.

[0016] In some aspects, alone or in combination with any of the previous aspects, the controller is coupled to a source of power.

[0017] In some examples, an outdoor walk-in refrigeration unit is also provided. The outdoor walk-in refrigeration unit includes one or more refrigeration systems operably coupled to at least one outdoor walk-in refrigeration unit, the one or more refrigeration systems each including: a conditioned space unit, the conditioned space unit being positioned at least partially in an ambient environment. A heating circuit is communicably coupled to a controller, where the heating circuit includes at least one heating element. A refrigeration circuit is communicably coupled to the controller, where the refrigeration system is configured to maintain a set temperature range in the conditioned space unit when an ambient temperature of the ambient environment is below the set temperature range.

[0018] In some examples, a method of maintaining a temperature of an outdoor walk-in refrigeration unit is also provided. The method includes providing one or more refrigeration systems operably coupled to at least one outdoor walk-in refrigeration unit, where each refrigeration system includes: a conditioned space unit, the conditioned space unit being positioned at least partially in an ambient environment. A heating circuit is communicably coupled to a controller, where the heating circuit includes at least one heating element. A refrigeration circuit is communicably coupled to the controller; and a temperature measuring device, sensing, via the temperature measuring device, that a temperature of the conditioned space unit is at or below an outside temperature adjacent the outdoor walk-in refrigeration unit and activating the heating circuit using the controller.

[0019] In some aspects, the method further comprises sensing, via the temperature measuring device, that the temperature of the conditioned space unit is above a maximum value of a set temperature range and activating the refrigeration circuit using the controller.

[0020] In some aspects, alone or in combination with any of the previous aspects, the refrigeration circuit further comprises: a compressor operably coupled to the refrigeration circuit, a condenser comprising a condenser input and a condenser output, and an evaporator comprising an evaporator input and an evaporator output. In one aspect, alone or in combination with any of the previous aspects, the evaporator input is communicably coupled to the condenser output and the evaporator output is communicably coupled to the condenser input.

[0021] In some aspects, alone or in combination with any of the previous aspects, the conditioned space unit is entirely located in the ambient environment. In one aspect, alone or in combination with any of the previous aspects, at least a portion of the conditioned space unit is physically attached to a structure and a remainder of the conditioned space unit is located in the ambient environment.

[0022] In some aspects, alone or in combination with any of the previous aspects, the at least one heating element is adjacent to a fan, wherein the fan is configured to direct a flow of air into the conditioned space unit. In one aspect, alone or in combination with any of the previous aspects, the fan and the at least one heating element are adjacent to the evaporator.

[0023] In some aspects, alone or in combination with any of the previous aspects, the temperature measuring device comprises a temperature probe. In one aspect, alone or in combination with any of the previous aspects, the temperature measuring device is configured to measure the temperature of the conditioned space unit. In one aspect, alone or in combination with any of the previous aspects, the temperature measuring device is operably coupled to the controller. In one aspect, alone or in combination with any of the previous aspects, the at least one heating element comprises a resistance heater.

[0024] In some aspects, alone or in combination with any of the previous aspects, the controller comprises an ignition-proof material. In one aspect, alone or in combination with any of the previous aspects, the heating circuit comprises at least one ignition-proof component.

[0025] In some aspects, alone or in combination with any of the previous aspects, the refrigeration system further comprises a circulating fan. In one aspect, alone or in combination with any of the previous aspects, the circulating fan is communicably coupled to the heating circuit and the refrigeration circuit. In one aspect, alone or in combination with any of the previous aspects, the circulating fan is configured to direct heated air away from the at least one heating element and into the conditioned space unit.

[0026] In some aspects, alone or in combination with any of the previous aspects, one or more components of the refrigeration system are installed in an outdoor environment. In one aspect, alone or in combination with any of the previous aspects, one or more components are exposed to an ambient environment.

[0027] In some aspects, alone or in combination with any of the previous aspects, the at least one heating element is positioned within the conditioned space unit. In one aspect, alone or in combination with any of the previous aspects, the ambient temperature is at or below a freezing point of water.

[0028] In some aspects, alone or in combination with any of the previous aspects, the refrigerant comprises an A3 refrigerant. In one aspect, alone or in combination with any of the previous aspects, the refrigeration circuit further comprises a maximum charge of 5.3 ounces of the A3 refrigerant per compressor. In one aspect, alone or in combination with any of the previous aspects, the refrigerant comprises propane.

[0029] In some aspects, alone or in combination with any of the previous aspects, the controller is coupled to a source of power.

[0030] It should be understood that while an exemplary system configuration is depicted with respect to the figures, these examples are non-limiting. It is envisioned that additional or alternative configurations may be included in the design of the refrigerant circuit, specifically depending on the specifications of the walk-in refrigeration unit. While certain exemplary examples have been described and shown in the accompanying drawings, it is to be understood that such examples are merely illustrative of and not restrictive on the broad disclosure, and that this disclosure not be limited to the specific constructions and arrangements shown and described, since various other changes, combinations, omissions, modifications and substitutions, in addition to those set forth in the above paragraphs, are possible. Those skilled in the art will appreciate that various adaptations, modifications, and combinations of the just described examples can be configured without departing from the scope and spirit of the present disclosure. Therefore, it is to be understood that, within the scope of the appended claims, the present disclosure may be practiced other than as specifically described herein.

[0031] The features, functions, and advantages that have been discussed may be achieved independently in various examples of the present disclosure or may be combined with yet other examples, further details of which can be seen with reference to the following description and drawings.

[0032] The above summary is provided merely for purposes of summarizing some example embodiments to provide a basic understanding of some aspects of the present disclosure. Accordingly, it will be appreciated that the above-described embodiments are merely examples and should not be construed to narrow the scope or spirit of the disclosure in any way. It will be appreciated that the scope of the present disclosure encompasses many potential embodiments in addition to those here summarized, some of which will be further described below.BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Having described certain example embodiments of the present disclosure in general terms above, reference will now be made to the accompanying drawings. The components illustrated in the figures may or may not be present in certain embodiments described herein. Some embodiments may include fewer (or more) components than those shown in the figures.

[0034] FIGS. 1A-1B are block diagrams illustrating operating environments for an example refrigeration system in accordance with one or more embodiments of the present disclosure;

[0035] FIGS. 2A-2B are block diagrams illustrating walk-in refrigeration units in accordance with one or more embodiments of the present disclosure;

[0036] FIG. 3 illustrates components of a refrigeration system in accordance with one or more embodiments of the present disclosure; and

[0037] FIG. 4 is a block diagram illustrating a refrigeration system in accordance with one or more embodiments of the present disclosure.DETAILED DESCRIPTION

[0038] As described above, in conventional refrigerant systems, such as in conventional walk-in foodservice cooler applications, baseboard heaters or other standalone heating devices with integrated controls have been used to maintain walk-in internal temperatures above the freezing point of water when the ambient (e.g., outdoor) temperature drops below freezing so as to prevent food spoilage by freezing. Providing improved efficiency with systems in low outdoor / ambient conditions whether using conventional refrigerants or alternative refrigerant solutions, namely those using flammable refrigerants and / or requiring reduced amounts of refrigerants remains a technical challenge, as standalone heating devices create a potential ignition source.

[0039] Thus, a need exists for a refrigeration system that has the ability to efficiently and safely heat a conditioned space when the ambient temperature falls below a certain or otherwise defined value. The presently disclosed system, in some examples, integrates a heating element into the refrigeration system thereby allowing both the refrigerant circuit and the heating element to be operated by the same controller. Specifically, the present disclosure may be adapted for outdoor use in cold climates by utilizing an auxiliary heating feature to maintain a consistent temperature range in a low temperature outdoor environment so as to compensate for heat transfer from the conditioned space to the outside / ambient environment.

[0040] Disclosed and described herein is a refrigeration system for an outdoor walk-in unit or conditioned space using an auxiliary heating feature to maintain a consistent temperature range. In some examples, the present disclosure is directed to refrigeration systems which use conventional refrigerants. In another example, the present disclosure is directed to refrigeration systems which use A3 classified refrigerants (according to the ISO817 Standard), such as R290 (e.g., propane). Because R290 is classified as a flammable refrigerant, adding a standalone heater to a refrigeration system using R290 may be undesirable as it may result in a fire hazard. In some examples, the refrigeration system includes electrical components which are either solid state or sealed to not be a potential source of ignition in the event of a leak when A3 type refrigerants are used. Thus, the present disclosure provides a refrigeration system configured to safely maintain a consistent temperature range using an auxiliary heating feature and ignition-proof components.

[0041] Examples of the present disclosure may be further directed to refrigeration systems which use conventional refrigerants or A3 classified refrigerants (according to the ISO817 Standard) in a walk-in refrigeration unit. In some examples, the A3 refrigerant is R290 (e.g., propane), which is an ultra-low GWP (Global Warming Potential) refrigerant that, when used in refrigeration systems, both lowers the energy consumed and reduces global warming. Being that R290 is classified as a flammable refrigerant it is restricted in the amount that can be safely used in a refrigeration circuit. For example, the current charge limit R290 is 150 gm (5.3 oz) per compressor in the United States. This charge restriction typically limits the refrigeration capacity of systems employing R290 as a refrigerant.

[0042] Examples of the present disclosure now may be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all, examples of the disclosure are shown. Indeed, the disclosure may be embodied in many different forms and should not be construed as limited to the examples set forth herein; rather, these examples are provided so that this disclosure may satisfy applicable legal requirements. Like numbers refer to like elements throughout.

[0043] It should be understood that “communicably coupled,” as used herein, encompasses components that are formed integrally with each other, or are formed separately and coupled together, for example, to allow the flow of refrigerant and / or heat. Furthermore, “communicably coupled” encompasses components that are formed directly to each other, or to each other with one or more components located between the components that are communicably coupled together. Furthermore, “communicably coupled” encompasses components that are detachable from each other, or that are permanently coupled together. Furthermore, communicably coupled components encompasses components that retain at least some freedom of movement in one or more directions or may be rotated about an axis (e.g., rotationally coupled, pivotally coupled). As would be evident to one of ordinary skill in the art in light of the present disclosure, in some embodiments, communicably coupled may refer to components that are in fluid communication with one another such that, for example, a refrigerant may flow be therebetween. By way of a non-limiting example, the components (e.g., compressor, condenser, evaporator, etc.) of an example refrigeration circuit may be in fluid communication (e.g., communicably coupled).

[0044] “Thermally coupled” or “in thermal communication” as used herein encompasses components that are directly or indirectly coupled so as to facilitate heat transfer between the components. Said heat transfer encompasses any type of heat transfer including radiation, conduction, convection, phase changes, and the like. Furthermore, “thermally coupled” encompasses components wherein a temperature change of one component affects a temperature of another component. Furthermore, “thermally coupled” encompasses any connection, coupling, link, or the like between components such that heat from one component is imparted to another component.

[0045] “Ambient environment” as used herein refers to a non-air-conditioned environment or non-temperature-regulated environment. Examples of a non-air-conditioned ambient environment include the outside / outdoors, or structures existing in the outdoors that are without a heating / cooling systems, e.g., barns, sheds, storage units and the like. “Ambient temperature” as used herein is an air temperature of the non-temperature-regulated ambient environment.

[0046] FIG. 1A illustrates an operating environment 100 for a refrigeration system 20, in accordance with an example of the present disclosure. The operating environment 100 comprises a walk-in refrigeration unit 10, a refrigeration system 20, and a coupled structure 12. As illustrated in FIG. 1A, the walk-in refrigeration unit 10 is positioned outdoors and not attached to or integrated with an air-conditioned coupled structure 12. The coupled structure 12 comprises any building such as a home, business, warehouse, and / or the like.

[0047] The walk-in refrigeration unit 10 comprises any refrigerated device or appliance (e.g., a refrigerator, cooler, and / or the like) configured to maintain a temperature-regulated environment within an interior storage space or compartment. In some examples, the walk-in refrigeration unit 10 comprises four walls, a floor, a celling and at least one entrance / door. Other shapes and configurations of the walk-in refrigeration unit 10 are contemplated. In some examples, the space regulated by the walk-in refrigeration unit 10 is configured to maintain a temperature at or above the freezing point of water at a fixed altitude or barometric pressure range, e.g., avoiding a temperature at which water freezes. In some examples, the space regulated by the walk-in refrigeration unit 10 is configured to maintain food at a temperature at or above the freezing point of water at a fixed altitude or barometric pressure range.

[0048] The temperature of the walk-in refrigeration unit 10 is maintained by a refrigeration system 20 installed or mounted to the walk-in refrigeration unit 10. As illustrated in FIG. 1A, because the walk-in refrigeration unit 10 is not integrated within the structure 12, the exterior of the walk-in refrigeration unit 10 is exposed to the ambient environment. As described above, “ambient environment” as used herein refers to a non-air-conditioned environment (i.e., any space or volume that is not enclosed by the walk-in refrigeration unit 10 and / or structure 12).

[0049] FIG. 1B illustrates an operating environment 101 for the refrigeration system 20, in accordance with examples of the present disclosure. The operating environment 101 comprises the walk-in refrigeration unit 10, the refrigeration system 20, and the coupled structure 12. As illustrated in FIG. 1B, the walk-in refrigeration unit 10 may be adjacent to the structure 12. In some examples, the walk-in refrigeration unit 10 shares a wall with the structure 12 and is accessible through the structure 12 but does not share a temperature-regulation system with the structure 12.

[0050] FIGS. 2A and 2B illustrate the walk-in refrigeration unit 10, in accordance with examples of the present disclosure. As illustrated in FIG. 2A, the walk-in refrigeration unit 10 comprises a conditioned space 102, a barrier 104, and the refrigeration system 20. In some examples, the conditioned space 102 comprises an enclosed temperature-regulated space within the walk-in refrigeration unit 10. As described with respect to FIG. 1A, the conditioned space 102 does not comprise a space regulated at a temperature lower than the freezing point of water (i.e., a freezer). In some examples, the barrier 104 is configured to separate the conditioned space 102 from the ambient environment (e.g., a wall, ceiling, roof, and / or the like). In some examples, the barrier 104 comprises a thickness of at least four inches.

[0051] In some examples, the refrigeration system 20 comprises a heating element 9, where the heating element 9 is communicably coupled to a circulating fan 6. In some examples, the circulating fan 6 is configured to direct heated air away from the heating element 9 and into the conditioned space 102. In some examples, the refrigeration system 20 is configured to allow airflow in a first direction 200 (e.g., into the conditioned space 102) and a second direction 201 (e.g., out of the conditioned space.

[0052] As illustrated in FIG. 2B, the refrigeration system 20 comprises a group of interior components 106 positioned or installed within the conditioned space 102 and a group of exterior components 108 positioned or installed outside of the conditioned space 102. In some examples, the interior components 106 and the exterior components 108 comprise the refrigeration system 20. In some examples, the walk-in refrigeration unit 10 comprises additional groups of system components in order to increase the overall refrigeration capacity of the walk-in refrigeration unit 10. In some examples, the interior components 106 and the exterior components 108 are coupled together via a liquid line 18 and suction line 13 as described in greater detail with respect to FIG. 4. In some examples, the liquid line 18 and suction line 13 are configured to pass through a hole, aperture, or passage in the barrier 104. In some examples, the interior components 106 are positioned within an area of the conditioned space 102 which allows for airflow 200 and 201 between the interior components 106 and the rest of the conditioned space 102.

[0053] FIG. 3 illustrates the group of interior components 106, in accordance with an embodiment of the present disclosure. In some examples, the interior components 106 comprise the heating element 9, an evaporator 5, and a housing 107. In some examples, the heating element 9 is positioned adjacent to the evaporator 5, allowing for heat transfer from the heating element 9 to the evaporator 5. The heating element 9 is configured to convert electrical energy into heat and comprises a suitable material such as a resistance wire or coil, ceramic and / or semiconductor compounds, quartz, thick film sheets, and / or composites of the same. In some examples, the evaporator 5 is located within the housing 107 and the heating element 9 is communicably coupled to an exterior of the housing 107.

[0054] FIG. 4 provides a block diagram illustrating the refrigeration system 20, in accordance with some examples of the present disclosure. The refrigeration system 20 is configured for use in the walk-in refrigeration unit 10. In some examples, the conditioned space 102 is separated from the ambient environment via a wall or barrier, wherein one or more components of the refrigeration system 20 are configured to pass through the barrier, as described in greater detail with respect to FIG. 2B. In some examples, components of the refrigeration system 20 are integrated into a single self-contained system.

[0055] FIG. 4 depicts a source of power 103 connected in series with a controller 1. In some examples, the source of power 103 comprises any direct current (DC) or alternating current (AC) voltage source (e.g., a generator, battery, fuel cell, and / or the like) configured to provide power to components of the refrigeration system 20. FIG. 2 further depicts a compressor 2 communicably coupled to an input of a condenser 3. The input of the condenser 3 leads to an output, which is communicably coupled to an input of an expansion device 4. The expansion device 4 comprises an output which is communicably coupled to an input of an evaporator 5 via a liquid line 18. The input of the evaporator 5 leads to an output, which is communicably coupled to the compressor 2. A condenser fan 7 is positioned near the condenser 3 and an evaporator fan 6 is positioned near the evaporator 5. The controller 1 and the source of power 103 are communicably coupled to the compressor 2.

[0056] The refrigeration system further comprises a temperature probe 8 which is communicably coupled to the controller 1. In some examples, the temperature probe comprises a thermometer or other temperature-measuring device positioned within the conditioned space 102. The temperature probe is configured to measure a temperature, or one or more temperature thresholds, of the conditioned space 102 and transmit data to the controller 1.

[0057] The refrigeration system further comprises a heating circuit 22, the heating circuit 22 comprising the heating element 9 and a switch (not shown), where the heating element 9 is controlled by the controller 1. In some examples, the heating element 9 is positioned adjacent to a circulating fan 6 configured to direct heated air away from the heating element 9 and into the conditioned space 102.

[0058] In some examples, the source of power 103 comprises any direct current (DC) or alternating current (AC) voltage source capable of providing power to the system components 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10. In some examples, the controller 1 is any ignition-proof electronic controller configured to provide logic and decisioning for the system 20. In some examples, the controller is configured to activate the compressor 2 in order to maintain and / or cycle about a set temperature point or between temperature thresholds or set points. In some examples, the controller 1 is configured to maintain a set point (e.g., between 32 and 40 degrees Fahrenheit or 0 and 5 degrees Celsius and is configured to activate the compressor when a sensed temperature deviates by one to three degrees from the set point. In some examples, the controller 1 is configured to activate the heating element when a sensed temperature deviates by one to three degrees from the set point. In some examples, the presently disclosed system may comprise multiple compressors 2 and may therefore include a controller configured to activate each compressor sequentially, for example, for avoiding an excessive surge in amperage which would result from each compressor 2 activating simultaneously. For example, the controller may be configured to activate each compressor 2 sequentially based on a sensed temperature from the temperature probe 8, a change in temperature, a manual input, or an event exceeding or falling below a temperature threshold. In some examples, electrical components of the refrigeration system (such as the controller 1) are either solid state or sealed so as to not be a potential source of ignition in the event of a leak.

[0059] In some examples, the refrigeration system 20 is configured to receive a refrigerant (not shown). The liquid refrigerant is configured to pass into an input of the evaporator 5. The at least one evaporator fan 6 may be positioned near the evaporator 5 and is configured to direct atmospheric air over the evaporator 5, causing evaporation of the liquid refrigerant.

[0060] In some examples, the compressor 2 is configured to pull cold, low-pressure gaseous refrigerant from the evaporator 5 into a compressor input. In some examples, the compressor 2 pulls the cold refrigerant through the suction line 13. The compressor 2 then raises the temperature and pressure of the refrigerant and outputs the heated refrigerant into an input of the condenser 3. In some examples, the at least one condenser fan 7 is positioned near the condenser 3 and is configured to direct atmospheric air over the condenser 3, causing the refrigerant to cool from a gaseous state to a liquid state. The refrigerant then flows through the liquid line 18 from an output of the condenser 3 into an input of the expansion device 4 for evaporative cooling.

[0061] In some examples, the system 20 comprises a plurality of compressors 2 connected in parallel between the outputs of the evaporator 5 and the inputs of the condenser 3. In some examples, the system 20 comprises a plurality of expansion devices 4 connected in parallel between the outputs of the condenser 3 and the inputs of the evaporator 5. Examples of such systems are found in co-assigned U.S. Pat. No. 11,859,885.

[0062] In some examples, the refrigeration system 20 may be configured for use in a walk-in refrigeration unit 10. In some examples, a single refrigeration system 20 is sufficient to provide the total refrigeration capacity of the walk-in refrigeration unit, or alternatively, multiple systems 20 are installed in order to provide sufficient refrigeration capacity. In some examples, refrigeration system 20 is configured within the refrigeration unit such that the condenser 3 and at least one condenser fan 7 are positioned outside of the conditioned space 102. In another example, evaporator 5 and at least one evaporator fan 6 are positioned inside of the conditioned space 102. In some examples, the condenser 3 and condenser fan 7 are separated from the evaporator 5 and evaporator fan 6 via a wall or barrier 104.

[0063] In some examples, the system 20 is configured to receive a refrigerant having a GWP (Global Warming Potential) value less than 10. Specifically, the system 20 is configured to receive R290 refrigerant (i.e. propane), which has a GWP value of 3. The current charge limit for R290 is 150 gm (5.3 oz) per compressor in the United States, and therefore the system 20 is configured to receive a charge less than 5.3 oz of R290 refrigerant per compressor.

[0064] Also, it will be understood that, where possible, any of the advantages, features, functions, devices, and / or operational aspects of any of the examples of the present disclosure described and / or contemplated herein are combinable and / or included in any of the other examples of the present disclosure described and / or contemplated herein, and / or vice versa. In addition, where possible, any terms expressed in the singular form herein are meant to also include the plural form and / or vice versa, unless explicitly stated otherwise.

Claims

1. A refrigeration system comprising:a conditioned space unit, wherein the conditioned space unit is positioned at least partially in an ambient environment;a heating circuit communicably coupled to a controller, wherein the heating circuit comprises at least one heating element; anda refrigeration circuit communicably coupled to the controller,wherein the refrigeration system is configured to maintain a set temperature range in the conditioned space unit when an ambient temperature of the ambient environment is below a freezing point of water at a fixed altitude or a barometric pressure range.

2. The refrigeration system of claim 1, wherein the refrigeration circuit comprises:a compressor operably coupled to the refrigeration circuit;a condenser comprising a condenser input and a condenser output; andan evaporator comprising an evaporator input and an evaporator output, wherein the evaporator input is communicably coupled to the condenser output and the evaporator output is communicably coupled to the condenser input.

3. The refrigeration system of claim 1, wherein the conditioned space unit is entirely located in the ambient environment.

4. The refrigeration system of claim 1, wherein at least a portion of the conditioned space unit is physically attached to a structure, and a remainder of the conditioned space unit is located in the ambient environment.

5. The refrigeration system of claim 1, wherein the at least one heating element is adjacent to a fan, wherein the fan is configured to direct a flow of air into the conditioned space unit.

6. The refrigeration system of claim 2, wherein the fan and the at least one heating element are adjacent to the evaporator.

7. The refrigeration system of claim 1, further comprising a temperature measuring device.

8. The refrigeration system of claim 7, wherein the temperature measuring device comprises a temperature probe.

9. The refrigeration system of claim 7, wherein the temperature measuring device is configured to measure the temperature of the conditioned space unit.

10. The refrigeration system of claim 9, wherein the temperature measuring device is operably coupled to the controller.

11. The refrigeration system of claim 1, wherein the controller is configured to activate the at least one heating element based on determining that a temperature of the conditioned space unit is below a minimum value of the set temperature range.

12. The refrigeration system of claim 10, wherein the controller is configured to activate the refrigeration circuit based on determining that a temperature of a conditioned space is above a maximum value of the set temperature range.

13. The refrigeration system of claim 1, wherein the controller comprises an ignition-proof material.

14. The refrigeration system of claim 1, wherein the heating circuit comprises at least one ignition-proof component.

15. The refrigeration system of claim 1, wherein the at least one heating element comprises a resistance heater.

16. The refrigeration system of claim 1, further comprising a circulating fan.

17. The refrigeration system of claim 16, wherein the circulating fan is communicably coupled to the heating circuit and the refrigeration circuit.

18. The refrigeration system of claim 16, wherein the circulating fan is configured to direct heated air away from the at least one heating element and into the conditioned space unit.

19. The refrigeration system of claim 1, wherein one or more components of the refrigeration system are installed in an outdoor environment.

20. The refrigeration system of claim 1, wherein one or more components are exposed to an ambient environment.

21. The refrigeration system of claim 1, wherein the at least one heating element is positioned within the conditioned space unit.

22. The refrigeration system of claim 1, wherein the ambient temperature is at or below a freezing point of water.

23. The refrigeration system of claim 1, wherein the refrigerant comprises an A3 refrigerant.

24. The refrigeration system of claim 23, wherein the refrigeration circuit further comprises a maximum charge of 5.3 ounces of the A3 refrigerant per compressor.

25. The refrigeration system of claim 1, wherein the refrigerant comprises propane.

26. The refrigeration system of claim 1, wherein the controller is coupled to a source of power.

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