HVAC UNIT WITH EXPANSION DEVICE

An outdoor HVAC unit includes a housing. A compressor is located within the housing. A heat exchanger is located within the housing and is in fluid communication with the compressor. At least one expansion device is located within the housing and is in fluid communication with the heat exchanger.

BACKGROUND

The present disclosure relates to refrigeration systems and, more particularly, to refrigeration systems with at least one indoor unit and at least one outdoor unit.

Buildings, such as university buildings, office buildings, residential buildings, commercial buildings, and the like, include climate systems which are operable to control the climate inside the building. A typical climate system includes an evaporator, a compressor, a condenser, and an expansion valve. These components utilize a refrigerant to maintain an indoor temperature of the buildings at a desired level.

SUMMARY

In one exemplary embodiment, an outdoor HVAC unit includes a housing. A compressor is located within the housing. A heat exchanger is located within the housing and is in fluid communication with the compressor. At least one expansion device is located within the housing and is in fluid communication with the heat exchanger.

In a further embodiment of any of the above, at least one isolation valve is in fluid communication with the compressor.

In a further embodiment of any of the above, the isolation value is fluidly upstream of the compressor. The at least one expansion device is fluidly downstream of the heat exchanger.

In a further embodiment of any of the above, the heat exchanger is a condenser.

In a further embodiment of any of the above, the at least one expansion device includes a plurality of expansion devices each in fluid communication with the heat exchanger.

In a further embodiment of any of the above, a plurality of liquid refrigerant lines are in fluid communication with the heat exchanger and a corresponding one of the plurality of expansion devices.

In a further embodiment of any of the above, the plurality of liquid lines are located within the housing.

In a further embodiment of any of the above, the outdoor unit operates with an A2L refrigerant.

In another exemplary embodiment, a refrigeration system includes an outdoor housing. A compressor is located within the outdoor housing. A first heat exchanger is located within the outdoor housing and is in fluid communication with the compressor. At least one expansion device is located within the outdoor housing and is in fluid communication with the heat exchanger. At least one second heat exchanger is located fluidly between the at least one expansion device and the compressor.

In a further embodiment of any of the above, the second heat exchanger is located within an indoor unit.

In a further embodiment of any of the above, at least one flow modulating valve is located fluidly between the at least one expansion device and the second heat exchanger.

In a further embodiment of any of the above, the first heat exchanger is a condenser. The second heat exchanger is an evaporator.

In a further embodiment of any of the above, a controller is configured to control the at least one modulating value, the at least one expansion device, and the compressor in response to a desired conditioning request.

In a further embodiment of any of the above, at least one isolation valve is located within the outdoor housing and fluidly between the at least one second heat exchanger and the compressor.

In a further embodiment of any of the above, a first fan is located adjacent the first heat exchanger and at least one second fan is located adjacent the at least one second heat exchanger.

In a further embodiment of any of the above, a plurality of liquid refrigerant lines are in fluid communication with the heat exchanger and a corresponding one of the at least one expansion devices.

In a further embodiment of any of the above, the refrigeration system operates with an A2L refrigerant.

In another exemplary embodiment, a method of operating a refrigeration system includes the step of fluidly isolating a first heat exchanger located within a housing of an outdoor unit from an indoor unit with at least one expansion device located within the outdoor unit. A second heat exchanger is fluidly isolated in the indoor unit from a compressor with at least on isolation valve located within the outdoor unit.

In a further embodiment of any of the above, at least one liquid refrigerant line extends from the first heat exchanger to the at least one expansion device. The at least one liquid refrigerant line is located within the housing of the outdoor unit.

In a further embodiment of any of the above, the refrigeration system operates with an A2L refrigerant.

DETAILED DESCRIPTION

A refrigeration system20is illustrated inFIG. 1and includes a compressor22delivering refrigerant into a discharge line23leading to a heat exchanger24, such as a condenser for subcritical applications and a gas cooler for trans-critical applications. The heat is transferred in the heat exchanger24from the refrigerant to a secondary loop fluid, such as ambient air, with a fan27. The high pressure, but cooled, refrigerant passes into a liquid refrigerant line25downstream of the heat exchanger24and through an expansion device26, where the refrigerant is expanded to a lower pressure and temperature. Downstream of the expansion device26, the refrigerant flows through an evaporator28and then through an isolation valve30before returning back to the compressor22. A fan29draws air to be conditioned through the evaporator28.

In the illustrated example, the compressor22, condenser24, expansion device26, and isolation valve30are located within a housing32to form an outdoor unit34. The expansion device26could include one of a TXV, a piston valve, or an EXV. Similarly, the evaporator28and the fan29are located in a housing36that forms an indoor unit38. Furthermore, the system20is configured to operate with an A2L refrigerant.

The configuration ofFIG. 1can be used in a number of applications, such as in residential systems. When used with a residential system, the evaporator28is located inside a residence and the fan29draws air through the evaporator28. Additionally, the fan29may be associated with a separate heating system for the residence. A controller40is either in direct electrical communication or wireless communication with the compressor22, the fans27,29, the expansion device26, and the isolation valve30to control or monitor operation of these elements. The controller40includes a microprocessor in communication with memory which stores programs to direct operation of the refrigeration system20.

In the event of a refrigerant leak within the refrigeration system20, the controller40can isolate refrigerant in the outdoor unit34from the indoor unit38by signaling the compressor22to stop along with signaling the isolation valve30and the expansion device26to move into a fully closed position that prevents the passage of refrigerant. One feature of this isolation approach with the outdoor unit34is that a greater percentage of refrigerant of the entire system20is captured in the outdoor unit34. In particular, a greater percentage is captured because the liquid refrigerant line25does not extend downstream of the outdoor unit34since the expansion device26is located within the housing32. This is due to the amount of refrigerant located in the liquid refrigerant line25being much greater per unit length than the amount of refrigerant in the refrigerant line connecting the expansion device26with the evaporator28.

FIG. 2illustrates example variable refrigerant flow (“VRF”) system50. In the illustrated example, the VRF system50includes a single outdoor unit52and multiple indoor units54. The outdoor unit52is located on an exterior of a building56while the indoor units54are located on an interior of the building56. Although the VRF system50only includes a single outdoor unit52in the illustrated example, the VRF system50could include multiple outdoor units52arranged in series depending on the heating and/or cooling needs of the building56. Additionally, the VRF system50is configured to operate with an A2L refrigerant.

In the illustrated example, the outdoor unit52includes a housing58enclosing an isolation valve60, a compressor62, a first heat exchanger64, a fan66, and multiple expansion devices68. The compressor62is in fluid communication with a suction line70that connects the compressor62with an outlet of the isolation valve60. Additionally, the compressor62is in fluid communication with a discharge line72that connects the compressor62with the first heat exchanger64. A liquid refrigerant line74connects an output of the first heat exchanger64with each of the three expansion devices68, such that the liquid refrigerant line74includes a branching portion between the first heat exchanger64and each of the expansion devices68.

In the illustrated example, the expansion devices68could include one of a TXV, a piston valve, or an EXV. An output of each of the expansion devices68is in fluid communication with an input line80that connects each of the expansion devices68with one of the indoor units54. One feature of having the liquid refrigerant line74located within the housing58is that the overall system refrigerant charge is reduced due to the reduction in length of the liquid refrigerant line74. This is due to the amount of refrigerant located in the liquid refrigerant line74being much greater per unit length than the amount of refrigerant in a corresponding one of the input lines80.

Each of the input lines80are in communication with a flow modulating valve82associated with each of the indoor units54. Although the flow modulating valves82are shown on an exterior of the indoor units54, the flow modulating valves82could be located within a housing84of the indoor units54. The flow modulating valves82are in electrical communication with individual temperature controls86to control a conditioned temperature of a region within the building56. To change the temperature in the corresponding region of the building56, the indoor units54each include a second heat exchanger90and a second fan92to move air within the building56over the second heat exchanger90.

Return lines94fluidly connect the second heat exchangers90in the indoor units54with the isolation valve60in the outdoor unit52. Although the isolation valve60is shown receiving each of the three return lines94in the illustrated example, an additional valve could be utilized to collect each of the return lines94into a single return line which would be in fluid communication with an input on the isolation valve60.

During operation of the VRF system50, the individual temperature controls86are used to control a temperature within the regions of the building56. To change the temperature, the individual temperature controls86can communicate with the individual flow modulating valves82for each of the associated indoor units54. Alternatively, the individual temperature controls86can communication with the rest of the VRF system50through a main controller88. The main controller88controls and monitors operation of the isolation valve60, the compressor62, the fans66and92, the expansion devices68, and/or the flow modulating valves82. The controller88includes a microprocessor in communication with memory which stores programs to direct operation of the VRF system50.

Furthermore, in the event of a refrigerant leak within the VRF system50, the main controller88can isolate refrigerant in the outdoor unit52from the rest of the indoor units54by signaling the compressor62to stop along with signaling the isolation valve60and each of the expansion devices68to move into a fully closed position that prevents the passage of refrigerant. One feature of this isolation approach with the outdoor unit52is that a greater percentage of refrigerant of the entire VRF system50is able to be captured in the outdoor unit52. In particular, a greater percentage is captured because the liquid refrigerant lines74do not extend downstream of the outdoor unit52since the expansion devices68are located within the housing58.

Although the different non-limiting examples are illustrated as having specific components, the examples of this disclosure are not limited to those particular combinations. It is possible to use some of the components or features from any of the non-limiting examples in combination with features or components from any of the other non-limiting examples.

It should be understood that like reference numerals identify corresponding or similar elements throughout the several drawings. It should also be understood that although a particular component arrangement is disclosed and illustrated in these exemplary embodiments, other arrangements could also benefit from the teachings of this disclosure.