Patent Description:
A climate-control system such as, for example, a heat-pump system, a refrigeration system, or an air conditioning system, may include a fluid circuit having an outdoor heat exchanger, one or more indoor heat exchangers, one or more expansion devices, and one or more compressors circulating a working fluid (e.g., refrigerant or carbon dioxide) through the fluid circuit. Efficient and reliable operation of the climate-control system is desirable to ensure that the climate-control system is capable of effectively and efficiently providing a cooling and/or heating effect on demand.

<CIT> discloses a climate-control system according to the preamble of claim <NUM>. <CIT> discloses a refrigerating plant; <CIT> discloses a load active heat pump combined two parallel single stage compressor.

This section provides a general summary of the invention, and is not a comprehensive disclosure of its full scope or all of its features.

According to the present invention, there is provided a climate-control system as defined in claim <NUM>. It comprises:
a first compressor having a first inlet and a first outlet; a second compressor in fluid communication with the first compressor and having second and third inlets, a second compression mechanism and a second outlet, the second and third inlets fluidly coupled to the second compression mechanism, the second compression mechanism configured to receive working fluid from the first compressor through the third inlet and is configured to discharge working fluid through the second outlet of the second compressor, wherein a first heat exchanger is in fluid communication with the second compressor and is configured to receive working fluid from the second compressor, wherein a second heat exchanger is in fluid communication with the first heat exchanger and includes a fourth inlet and third and fourth outlets, the fourth inlet receives working fluid from the first heat exchanger, the third outlet provides working fluid to the first inlet, wherein a first expansion device is disposed between the first heat exchanger and the second heat exchanger, wherein the fourth outlet of the second heat exchanger provides working fluid to the second inlet of the second compressor, and wherein the climate-control system further comprises a third heat exchanger disposed between the first and second compressors and including a fifth inlet, a fifth outlet providing working fluid to the second inlet of the second compressor, and a sixth outlet providing working fluid to the third inlet of the second compressor.

In some configurations of the climate-control system of any one or more of the above paragraphs, a first fluid passageway extends from the fourth outlet of the second heat exchanger through the third heat exchanger and provides working fluid from the fourth outlet of the second heat exchanger to the second inlet of the second compressor.

In some configurations of the climate-control system of any one or more of the above paragraphs, a second expansion device is disposed along the first fluid passageway at a location upstream of the third heat exchanger and a third expansion device disposed along the first fluid passageway at a location downstream of the third heat exchanger.

In some configurations of the climate-control system of any one or more of the above paragraphs, a second fluid passageway extends from a liquid conduit fluidly coupled to the third outlet of the second heat exchanger to the first fluid passageway.

In some configurations of the climate-control system of any one or more of the above paragraphs, the second fluid passageway includes a fourth heat exchanger and a fourth expansion device.

In some configurations of the climate-control system of any one or more of the above paragraphs, a third fluid passageway extends from the liquid conduit fluidly coupled to the third outlet of the second heat exchanger and provides working fluid from the liquid conduit to the first inlet of the first compressor.

In some configurations of the climate-control system of any one or more of the above paragraphs, the third fluid passageway includes a fifth heat exchanger and a fifth expansion device.

In some configurations of the climate-control system of any one or more of the above paragraphs, the fourth heat exchanger is a medium-temperature heat exchanger and the fifth heat exchanger is a low-temperature heat exchanger.

In some configurations of the climate-control system of any one or more of the above paragraphs, the second heat exchanger is a flash tank. The third outlet is a liquid outlet and the fourth outlet is a vapor outlet.

In some configurations of the climate-control system of any one or more of the above paragraphs, a bypass passageway extends from the first fluid passageway at a location upstream of the third heat exchanger to the first fluid passageway at a location downstream of the third heat exchanger.

In some configurations of the climate-control system of any one or more of the above paragraphs, a first fluid passageway is in fluid communication with the first outlet of the first compressor and provides working fluid from the first outlet of the first compressor to the third inlet of the second compressor.

In some configurations of the climate-control system of any one or more of the above paragraphs, a first <NUM>-way valve is disposed along the first fluid passageway. The first <NUM>-way valve includes a fourth inlet and third and fourth outlets.

In some configurations of the climate-control system of any one or more of the above paragraphs, the second inlet of the second compressor is in fluid communication with the third outlet of the first <NUM>-way valve and receives working fluid from the third outlet of the first <NUM>-way valve.

In some configurations of the climate-control system of any one or more of the above paragraphs, the fourth outlet of the first <NUM>-way valve provides working fluid to one of the third inlet of the second compressor and the first heat exchanger.

In some configurations of the climate-control system of any one or more of the above paragraphs, a second <NUM>-way valve is disposed along the first fluid passageway at a location downstream of the first <NUM>-way valve. The second <NUM>-way valve includes a fifth inlet and fifth and sixth outlets.

In some configurations of the climate-control system of any one or more of the above paragraphs, a second fluid passageway receives working fluid from the second outlet of the second compressor and includes the first heat exchanger. A third fluid passageway extends from the fifth outlet of the second <NUM>-way valve to the second fluid passageway.

In some configurations of the climate-control system of any one or more of the above paragraphs, the fifth inlet of the second <NUM>-way valve is in fluid communication with the fourth outlet of the first <NUM>-way valve and receives working fluid from the fourth outlet of the first <NUM>-way valve.

In some configurations of the climate-control system of any one or more of the above paragraphs, the sixth outlet of the second <NUM>-way valve is in fluid communication with the third inlet of the second compressor and provides working fluid to the third inlet of the second compressor.

In some configurations of the climate-control system of any one or more of the above paragraphs, a first heat exchanger is in fluid communication with the second compressor and receives working fluid from the second compressor.

In some configurations of the climate-control system of any one or more of the above paragraphs, a second heat exchanger is in fluid communication with the first heat exchanger and includes a fourth inlet and third and fourth outlets. The fourth inlet receives working fluid from the first heat exchanger. The third outlet provides working fluid to the first inlet.

In some configurations of the climate-control system of any one or more of the above paragraphs, the first compressor includes a sixth inlet and a first compression mechanism. The sixth inlet of the first compressor is fluidly coupled the first compression mechanism and the first compression mechanism receives working fluid from the second heat exchanger through the sixth inlet of the first compressor.

In some configurations of the climate-control system of any one or more of the above paragraphs, a first fluid passageway extends from the fourth outlet of the second heat exchanger and provides working fluid from the fourth outlet of the second heat exchanger to the fifth inlet of the first compressor. A second fluid passageway extends from a liquid conduit fluidly coupled to the third outlet of the second heat exchanger and provides working fluid from the liquid conduit to the second inlet of the second compressor.

In some configurations of the climate-control system of any one or more of the above paragraphs, the first fluid passageway includes a second expansion device.

In some configurations of the climate-control system of any one or more of the above paragraphs, the second fluid passageway includes a third heat exchanger and a third expansion device.

In some configurations of the climate-control system of any one or more of the above paragraphs, a third fluid passageway extends from the liquid conduit fluidly coupled to the third outlet of the second heat exchanger and provides working fluid from the liquid conduit to the first inlet of the first compressor. A fourth fluid passageway is in fluid communication with the first outlet of the first compressor and provides working fluid to the third inlet of the second compressor.

In some configurations of the climate-control system of any one or more of the above paragraphs, the third fluid passageway includes a fourth heat exchanger and a fourth expansion device.

In some configurations of the climate-control system of any one or more of the above paragraphs, the third heat exchanger is a medium-temperature heat exchanger and the fourth heat exchanger is a low-temperature heat exchanger.

In another form, a climate-control system of the present disclosure may include a first working-fluid circuit, a second working-fluid circuit and a first heat exchanger. The first working-fluid circuit may include a first compressor and a second heat exchanger. The first compressor may have first and second inlets, a compression mechanism and an outlet. The first and second inlets may be fluidly coupled to the compression mechanism. The second heat exchanger may receive a first working fluid from the outlet of the first compressor. The second working-fluid circuit may include a second compressor and a third heat exchanger. The third heat exchanger may be in fluid communication with the second compressor. The first heat exchanger may be thermally coupled with the first working-fluid circuit and the second working-fluid circuit. The compression mechanism may receive a first working-fluid circuit exiting the first heat exchanger through the second inlet.

In some configurations, the first working-fluid circuit and the second working-fluid circuit are fluidly isolated from each other.

In some configurations of the climate-control system of any one or more of the above paragraphs, the first heat exchanger includes first and second conduits. The first conduit is in fluid communication with the first working-fluid circuit and the second conduit is in fluid communication with the second working-fluid circuit.

In some configurations of the climate-control system of any one or more of the above paragraphs, the first working-fluid circuit includes a first expansion device disposed between the second heat exchanger and the first conduit of the first heat exchanger.

In some configurations of the climate-control system of any one or more of the above paragraphs, the first working-fluid circuit includes a first fluid passageway that is in fluid communication with the outlet of the first compressor and provides working fluid to the second inlet of the first compressor.

In some configurations of the climate-control system of any one or more of the above paragraphs, the first working-fluid circuit includes a second fluid passageway that extends from the first fluid passageway at a location between the second heat exchanger and the first expansion device and to the first inlet of the first compressor.

In some configurations of the climate-control system of any one or more of the above paragraphs, the second fluid passageway includes a fourth heat exchanger and a second expansion device.

In some configurations of the climate-control system of any one or more of the above paragraphs, a third expansion device is disposed between the second conduit of the first heat exchanger and the third heat exchanger.

In some configurations of the climate-control system of any one or more of the above paragraphs, the third heat exchanger is a low-temperature heat exchanger and the fourth heat exchanger is a medium-temperature heat exchanger.

Example embodiments are provided so that this invention will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present invention. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms The scope of the present invention is defined by the appended claims.

With reference to <FIG>, a climate-control system <NUM> is provided that may include a fluid-circuit having one or more first compressors <NUM>, one or more second compressors <NUM>, a first heat exchanger <NUM> (an outdoor heat exchanger such as a condenser or gas cooler, for example), a first expansion device <NUM>, a flash tank (a second heat exchanger) <NUM>, a third heat exchanger <NUM>, a fourth heat exchanger <NUM> (an indoor heat exchanger such as a medium-temperature evaporator, for example) and a fifth heat exchanger <NUM> (an indoor heat exchanger such as a low-temperature evaporator, for example). The first compressors <NUM> and/or the second compressors <NUM> may pump working fluid (e.g., refrigerant, carbon dioxide, etc.) through the circuit.

Each first compressor <NUM> may be a low-side compressor (i.e., a compressor in which the motor assembly is disposed within a suction-pressure chamber within the shell), for example, and may be any suitable type of compressor such as a scroll, rotary, reciprocating or screw compressor, for example. Each first compressor <NUM> includes a compression mechanism <NUM> disposed within a shell <NUM> having an inlet <NUM> (e.g., a first inlet fitting) and an outlet <NUM> (e.g., an outlet fitting). The inlet <NUM> may provide fluid to a suction inlet (not shown) of the compression mechanism <NUM> (e.g., a radially outermost pocket of a scroll compression mechanism). Suction lines <NUM> may be fluidly coupled to a first header <NUM> and corresponding inlets <NUM> of the first compressors <NUM>. In this manner, working fluid exiting the fifth heat exchanger <NUM> may flow into the first header <NUM> where it is distributed to the suction lines <NUM> and the inlets <NUM> of the first compressors <NUM> to be compressed by the compression mechanisms <NUM> of the first compressors <NUM>. After the working fluid is compressed by the compression mechanisms <NUM> of the first compressors <NUM>, the working fluid can be discharged from the first compressors <NUM> through the outlets <NUM> to a second header <NUM> via discharge lines <NUM>.

In some configurations, each first compressor <NUM> could be a high-side compressor (i.e., a compressor in which the motor assembly is disposed within a discharge-pressure chamber within the shell). In some configurations, each of the first compressors <NUM> may have different capacities than one another or than the second compressors <NUM>. In some configurations, one or more of the first compressors <NUM> or one or more of the second compressors <NUM> may include a fixed-speed or variablespeed motor.

Referring now to <FIG>, each second compressor <NUM> may be a low-side scroll compressor including a hermetic shell assembly <NUM>, a main bearing housing assembly <NUM>, a motor assembly <NUM>, a compression mechanism <NUM>, a seal assembly <NUM>, a discharge fitting <NUM>, a discharge valve assembly <NUM>, a suction gas inlet fitting <NUM> and an S-shaped vapor-injection conduit <NUM> (e.g., a second inlet). The shell assembly <NUM> may house the main bearing housing assembly <NUM>, the motor assembly <NUM>, the compression mechanism <NUM> and the seal assembly <NUM>, and may at least partially house the vapor-injection conduit <NUM>.

The shell assembly <NUM> may generally form a compressor housing and may include a cylindrical shell <NUM>, an end cap <NUM> at the upper end thereof, a transversely extending partition <NUM> and a base <NUM> at a lower end thereof. The end cap <NUM> and the partition <NUM> may generally define a discharge chamber <NUM>, while the cylindrical shell <NUM>, the partition <NUM> and the base <NUM> may generally define a suction chamber <NUM>. The discharge fitting <NUM> may be attached to the shell assembly <NUM> at an opening <NUM> in the end cap <NUM> and may be in fluid communication with a third header <NUM> via a discharge line <NUM>. The discharge valve assembly <NUM> may be located within the discharge fitting <NUM> and may generally prevent a reverse flow condition. The suction gas inlet fitting <NUM> may be attached to the shell assembly <NUM> at an opening <NUM> such that the suction gas inlet fitting <NUM> is in fluid communication with the suction chamber <NUM> and a fourth header <NUM> via a suction line <NUM>. The partition <NUM> may include a discharge passage <NUM> therethrough that provides communication between the compression mechanism <NUM> and the discharge chamber <NUM>.

The main bearing housing assembly <NUM> may be affixed to the shell at a plurality of points in any desirable manner, such as staking, for example. The main bearing housing assembly <NUM> may include a main bearing housing <NUM>, a first bearing <NUM> disposed therein, bushings <NUM> and fasteners <NUM>. The main bearing housing <NUM> may include a central body portion <NUM> having a series of arms <NUM> that extend radially outwardly therefrom. The central body portion <NUM> may include first and second portions <NUM> and <NUM> having an opening <NUM> extending therethrough. The second portion <NUM> may house the first bearing <NUM> therein. The first portion <NUM> may define an annular flat thrust bearing surface <NUM> on an axial end surface thereof. Each arm <NUM> may include an aperture <NUM> extending therethrough that receives a respective fastener <NUM>.

The motor assembly <NUM> may generally include a motor stator <NUM>, a rotor <NUM>, and a drive shaft <NUM>. The motor stator <NUM> may be press-fit into the shell <NUM>. The drive shaft <NUM> may be rotatably driven by the rotor <NUM>. The rotor <NUM> may be press-fit onto the drive shaft <NUM>. The drive shaft <NUM> may include an eccentric crank pin <NUM> having a flat <NUM> thereon.

The compression mechanism <NUM> may generally include an orbiting scroll <NUM> and a non-orbiting scroll <NUM>. The orbiting scroll <NUM> may include an endplate <NUM> having a spiral vane or wrap <NUM> on the upper surface thereof and an annular flat thrust surface <NUM> on the lower surface. The thrust surface <NUM> may interface with the annular flat thrust bearing surface <NUM> on the main bearing housing <NUM>. A cylindrical hub <NUM> may project downwardly from the thrust surface128 and may have a drive bushing <NUM> rotatably disposed therein. The drive bushing <NUM> may include an inner bore in which the crank pin <NUM> is drivingly disposed. The crank pin flat <NUM> may drivingly engage a flat surface of the inner bore of the drive bushing <NUM> to provide a radially compliant driving arrangement. An Oldham coupling <NUM> may be engaged with the orbiting and non-orbiting scrolls <NUM>, <NUM> to prevent relative rotation therebetween.

The non-orbiting scroll <NUM> may include an endplate <NUM> having a spiral wrap <NUM> on a lower surface <NUM> thereof and a series of radially outwardly extending flanged portions <NUM>. The spiral wrap <NUM> may form a meshing engagement with the wrap <NUM> of the orbiting scroll <NUM>, thereby creating compression pockets, including an inlet pocket <NUM>, intermediate pockets <NUM>, <NUM>, <NUM>, <NUM>, and an outlet pocket <NUM>. The non-orbiting scroll <NUM> may be axially displaceable relative to the main bearing housing assembly <NUM>, the shell assembly <NUM>, and the orbiting scroll <NUM>. The non-orbiting scroll <NUM> may include a discharge passage <NUM> in communication with the outlet pocket <NUM> and an upwardly open recess <NUM>. The upwardly open recess <NUM> may be in fluid communication with the discharge chamber <NUM> via the discharge passage <NUM> in the partition <NUM>.

The endplate <NUM> may include an injection passage <NUM> formed therein. The injection passage <NUM> may be in fluid communication with the vapor-injection conduit <NUM> and with one or more of the intermediate pockets <NUM>, <NUM>, <NUM>, <NUM> and may include a radially extending portion <NUM> and an axially extending portion <NUM>. The injection passage <NUM> may allow working fluid from the vapor-injection conduit <NUM> to flow into the one or more of the intermediate pockets <NUM>, <NUM>, <NUM>, <NUM>.

The flanged portions <NUM> may include openings <NUM> therethrough. Each opening <NUM> may receive a respective bushing <NUM> therein. Each bushing <NUM> may receive a respective fastener <NUM>. The respective fastener <NUM> may be engaged with the main bearing housing <NUM> to prevent rotation of the non-orbiting scroll <NUM> relative to the main bearing housing assembly <NUM>. The non-orbiting scroll <NUM> may include an annular recess <NUM> in the upper surface thereof defined by parallel and coaxial inner and outer sidewalls <NUM>, <NUM>.

The seal assembly <NUM> may be located within the annular recess <NUM>. In this way, the seal assembly <NUM> may be axially displaceable within the annular recess <NUM> relative to the shell assembly <NUM> and/or the non-orbiting scroll <NUM> to provide for axial displacement of the non-orbiting scroll <NUM> while maintaining a sealed engagement with the partition <NUM> to isolate the discharge chamber <NUM> from the suction chamber <NUM>. More specifically, in some configurations, pressure within the annular recess <NUM> may urge the seal assembly <NUM> into engagement with the partition <NUM>, and the spiral wrap <NUM> of the non-orbiting scroll <NUM> into engagement with the endplate <NUM> of the orbiting scroll <NUM>, during normal compressor operation.

The vapor-injection conduit <NUM> may be at least partially disposed in the shell <NUM> and may be attached to the shell <NUM> at an opening thereof. The vapor-injection conduit <NUM> may include a first end <NUM> in fluid communication with the injection passage <NUM> and a second end <NUM> attached to the shell <NUM> and in fluid communication with a fifth header <NUM> (via a vapor inlet line <NUM>).

While each second compressor <NUM> is described above as a low-side scroll compressor (i.e., a compressor in which the motor assembly is disposed within a suction-pressure chamber within the shell), in some configurations, each second compressor <NUM> could be a high-side compressor (i.e., a compressor in which the motor assembly is disposed within a discharge-pressure chamber within the shell). For example, each second compressor <NUM> could be a high-side or low-side compressor and could be a rotary, reciprocating, or screw compressor, or any other suitable type of compressor. It is understood that, in some configurations, each first compressor <NUM> may be similar or identical to each second compressor <NUM>.

Referring again to <FIG>, the first heat exchanger <NUM> may be in fluid communication with the second compressors <NUM> via the third header <NUM>. That is, the third header <NUM> may receive the compressed working fluid from the discharge lines <NUM> and the discharge fittings <NUM> of the second compressors <NUM> and may direct the compressed working fluid to the first heat exchanger <NUM>. The first heat exchanger <NUM> may transfer heat from the compressed working fluid to ambient air that may be forced over the first heat exchanger <NUM> by a fan (not shown). In some configurations, the first heat exchanger <NUM> may transfer heat from the compressed working fluid to a stream of liquid such as water, for example. From the first heat exchanger <NUM>, the working fluid may flow through the first expansion device <NUM> (e.g., an expansion valve or capillary tube), thereby lowering the temperature and pressure of the working fluid. From the first expansion device <NUM>, the working fluid may flow into an inlet <NUM> of the flash tank <NUM>.

In the flash tank <NUM>, liquid working fluid is separated from vapor working fluid. Vapor working fluid may exit the flash tank <NUM> through a vapor outlet <NUM>. Liquid working fluid may exit the flash tank <NUM> through a liquid outlet <NUM>. From the vapor outlet <NUM>, the vapor working fluid flows into a first fluid passageway <NUM> extending from the vapor outlet <NUM> through the third heat exchanger <NUM> and to the fourth header <NUM>. The first fluid passageway <NUM> includes second and third expansion devices <NUM>, <NUM> and a conduit <NUM> of the third heat exchanger <NUM>. The second expansion device <NUM> (e.g., an expansion valve or capillary tube) may be disposed along the first fluid passageway <NUM> upstream of the third heat exchanger <NUM> and the third expansion device <NUM> (e.g., an expansion valve or capillary tube) may be disposed along the first fluid passageway <NUM> downstream of the third heat exchanger <NUM>.

Vapor working fluid in the first fluid passageway <NUM> flows through the second expansion device <NUM> where its temperature and pressure is lowered. The vapor working fluid then flows through the conduit <NUM> of the third heat exchanger <NUM> and the third expansion device <NUM> where its temperature and pressure is lowered. From the third expansion device <NUM>, the vapor working fluid may flow into the fourth header <NUM> where it is distributed to the suction lines <NUM> and the suction gas inlet fittings <NUM> of the second compressors <NUM> to be compressed by the compression mechanisms <NUM> of the second compressors <NUM>.

In some configurations, a bypass passageway <NUM> may extend from the first fluid passageway <NUM> at a location upstream of the third heat exchanger <NUM> to the first fluid passageway <NUM> at a location downstream of the third heat exchanger <NUM> (i.e., bypassing the third heat exchanger <NUM>). A bypass valve <NUM> may be disposed along the bypass passageway <NUM> and may be movable between open and closed positions. In the open position, the bypass valve <NUM> may allow fluid to flow from the first fluid passageway <NUM> upstream of the third heat exchanger <NUM> to the second compressors <NUM> (i.e., bypassing the third heat exchanger <NUM> and the third expansion device <NUM>). It will be appreciated that the bypass valve <NUM> could be a solenoid valve, a mechanical valve actuated by fluid-pressure differentials, or an electronic expansion valve, for example, or any other type of valve.

From the liquid outlet <NUM>, the working fluid may flow into a liquid conduit <NUM>. A first portion of the working fluid in the liquid conduit <NUM> flows into a second fluid passageway <NUM> extending from the liquid conduit <NUM> to the first fluid passageway <NUM> at a location between the second expansion device <NUM> and the conduit <NUM> of the third heat exchanger <NUM>. The second fluid passageway <NUM> includes a fourth expansion <NUM> and the fourth heat exchanger <NUM>. The working fluid in the second fluid passageway <NUM> flows through the fourth expansion device <NUM> where its temperature and pressure is lowered. In the fourth heat exchanger <NUM>, the first portion of the working fluid may absorb heat from a first space to be cooled (e.g., an interior of a refrigerator, a refrigerated display case, or a cooler). From the fourth heat exchanger <NUM>, the working fluid flows to the first fluid passageway <NUM> where it is mixed with the vapor working fluid prior to the working fluid entering the conduit <NUM> of the third heat exchanger <NUM>.

A second portion of the working fluid in the liquid conduit <NUM> flows into a third fluid passageway <NUM> extending from the liquid conduit <NUM> to the first header <NUM>. The third fluid passageway <NUM> includes a fifth expansion device <NUM> and the fifth heat exchanger <NUM>. The working fluid in the third fluid passageway <NUM> flows through the fifth expansion device <NUM> where its temperature and pressure is lowered. In the fifth heat exchanger <NUM>, the working fluid may absorb heat from a second space to be cooled (e.g., freezer or a frozen food display case). In some configurations, the working fluid in the fourth heat exchanger <NUM> of the second fluid passageway <NUM> and the working fluid in the fifth heat exchanger <NUM> of the third fluid passageway <NUM> may absorb heat from the same space (e.g., the fourth heat exchanger <NUM> of the second fluid passageway <NUM> and the fifth heat exchanger <NUM> of the third fluid passageway <NUM> may operate at different times to switch the space between a freezer and a cooler, for example). From the fifth heat exchanger <NUM>, the working fluid may flow into the first header <NUM> where it is distributed to the suction lines <NUM> and the inlets <NUM> of the first compressors <NUM> to be compressed by the compression mechanisms <NUM> of the first compressors <NUM>.

After the working fluid is compressed by the compression mechanisms <NUM> of the first compressors <NUM>, the compressed working fluid can be discharged from the first compressors <NUM> to a fourth fluid passageway <NUM> (via the discharge lines <NUM> and the second header <NUM>). The fourth fluid passageway <NUM> may extend from the second header <NUM> through the third heat exchanger <NUM> to the fifth header <NUM>. The compressed working fluid flowing through a conduit <NUM> of the third heat exchanger <NUM> absorbs heat from the working fluid in the conduit <NUM>. From the fifth header <NUM>, the working fluid is distributed to the vapor inlet lines <NUM> and into the intermediate pockets <NUM>, <NUM>, <NUM>, <NUM> of the compression mechanisms <NUM> of the second compressors <NUM> (via the vapor-injection conduits <NUM>).

As shown in <FIG>, a control module <NUM> may be in communication with the first compressors <NUM>, the second compressors <NUM>, the first, second, third, fourth and fifth expansion devices, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and the bypass valve <NUM>. The control module <NUM> may control operation of the first compressors <NUM>, the second compressors <NUM>, the first, second, third, fourth and fifth expansion devices, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and the bypass valve <NUM> based at least partially on one or more sensors (pressure and/or temperature sensors) positioned within and/or attached to the first and second compressors <NUM>, <NUM>. The one or more sensors may also be disposed along the suction lines <NUM> and the discharge lines <NUM> of the first compressors <NUM> and the suction lines <NUM>, the discharge lines <NUM> and the vapor inlet lines <NUM> of the second compressors <NUM>. The one or more sensors can communicate data to the control module <NUM>. Based on the data received from the one or more sensors, the control module <NUM> can open and close the expansion devices, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and the bypass valve <NUM>, and control operation of the first and second compressors <NUM>, <NUM>.

One of the benefits of the climate-control system <NUM> of the present disclosure is that the working fluid discharged from the first compressors <NUM> may be directed to the intermediate pockets <NUM>, <NUM>, <NUM>, <NUM> of the compression mechanisms <NUM> of the second compressors <NUM> as opposed to mixing with the working fluid in the first fluid passageway <NUM> prior to the working fluid in the first fluid passageway <NUM> entering into the second compressors <NUM> (via the suction lines <NUM>). This improves system efficiency (e.g., by providing extra output or capacity of the compressors <NUM> and gaining system capacity through cooling of the working fluid in the intermediate pockets <NUM>, <NUM>, <NUM>, <NUM> of the second compressors <NUM>) while at the same time avoiding having to size the suction lines <NUM> to account for the flow of the compressed working fluid exiting the first compressors <NUM>.

With reference to <FIG>, another climate-control system <NUM> is provided that may be generally similar to the climate-control system <NUM> described above, apart from any exception noted below. The climate-control system <NUM> may include a fluid circuit having first compressors <NUM>, second compressors <NUM>, a first heat exchanger <NUM> (an outdoor heat exchanger such as a condenser or gas cooler, for example), a first expansion device <NUM>, a flash tank (or second heat exchanger) <NUM>, a third heat exchanger <NUM> (an indoor heat exchanger such as a medium-temperature evaporator, for example) and a fourth heat exchanger <NUM> (an indoor heat exchanger such as a low-temperature evaporator, for example). The structure and function of the second compressors <NUM>, the first heat exchanger <NUM>, the flash tank <NUM>, the third heat exchanger <NUM>, the fourth heat exchanger <NUM> and the control module (not shown) may be similar or identical to that of the second compressors <NUM>, the first heat exchanger <NUM>, the flash tank <NUM>, the fourth heat exchanger <NUM>, the fifth heat exchanger <NUM> and the control module <NUM>, respectively, described above, and therefore, will not be described again in detail.

Each first compressor <NUM> may include a shell <NUM>, a compression mechanism <NUM> and a vapor-injection conduit <NUM> (e.g., a second inlet). The compression mechanism <NUM> may be disposed within the shell <NUM> having an inlet <NUM> (e.g., a first inlet fitting) and an outlet <NUM> (e.g., an outlet fitting). The inlet <NUM> may provide fluid to a suction inlet (not shown) of the compression mechanism <NUM> (e.g., a radially outermost pocket of a scroll compression mechanism). Suction lines <NUM> may be fluidly coupled to a first header <NUM> and corresponding inlets <NUM> of the first compressors <NUM>. In this manner, working fluid exiting the fourth heat exchanger <NUM> may flow into the first header <NUM> where it is distributed to the suction lines <NUM> and the inlets <NUM> of the first compressors <NUM> to be compressed by the compression mechanisms <NUM> of the first compressors <NUM>. After the working fluid is compressed by the compression mechanisms <NUM> of the first compressors <NUM>, the working fluid can be discharged from the first compressors <NUM> through the outlets <NUM> to a second header <NUM> via discharge lines <NUM>.

The vapor-injection conduit <NUM> may be at least partially disposed within the shell <NUM> and may be attached to the shell <NUM> at an opening thereof. The vapor-injection conduit <NUM> may include a first end in fluid communication with intermediate pockets of the compression mechanism <NUM> and a second end in fluid communication with a third header <NUM> (via a vapor inlet line <NUM>).

The climate-control system <NUM> may also include a first fluid passageway <NUM>, a second fluid passageway <NUM>, a third fluid passageway <NUM> and a fourth fluid passageway <NUM>. The first fluid passageway <NUM> may extend from a vapor outlet <NUM> of the flash tank <NUM> to the third header <NUM> and may include a second expansion device <NUM> (e.g., an expansion valve or capillary tube). Vapor working fluid in the first fluid passageway <NUM> flows through the second expansion device <NUM> where its temperature and pressure is lowered. The vapor working fluid then flows through the third header <NUM> where it is distributed to the vapor inlet lines <NUM> and into the intermediate pockets of the compression mechanisms <NUM> of the first compressors <NUM> (via the vapor-injection conduits <NUM>).

The second fluid passageway <NUM> extends from a liquid conduit <NUM> (that is fluidly coupled to a liquid outlet <NUM> of the flash tank <NUM>) to a fourth header <NUM> that is in fluid communication with the second compressors <NUM> via suction lines <NUM>. The second fluid passageway <NUM> includes a third expansion device <NUM> (e.g., an expansion valve or capillary tube) and the third heat exchanger <NUM>. A portion of the working fluid flowing through the liquid conduit <NUM> flows through the third expansion device <NUM> of the second fluid passageway <NUM> where its temperature and pressure is lowered. In the third heat exchanger <NUM>, the working fluid may absorb heat from a first space to be cooled (e.g., an interior of a refrigerator, a refrigerated display case, or a cooler). From the third heat exchanger <NUM>, the working fluid flows to the fourth header <NUM> where it is distributed to the suction lines <NUM> and the second compressors <NUM> to be compressed by compression mechanisms <NUM> of the second compressors <NUM>.

The third fluid passageway <NUM> extends from the liquid conduit <NUM> to the first header <NUM> that is in fluid communication with the inlet <NUM> of the first compressors <NUM> via the suction lines <NUM>. The third fluid passageway <NUM> includes a fourth expansion device <NUM> and the fourth heat exchanger <NUM>. Another portion of the working fluid flowing through the liquid conduit <NUM> flows through the fourth expansion device <NUM> of the third fluid passageway <NUM> where its temperature and pressure is lowered. In the fourth heat exchanger <NUM>, the working fluid may absorb heat from a second space to be cooled (e.g., freezer or a frozen food display case). In some configurations, the working fluid in the third heat exchanger <NUM> of the second fluid passageway <NUM> and the working fluid in the fourth heat exchanger <NUM> of the third fluid passageway <NUM> may absorb heat from the same space (e.g., the third heat exchanger <NUM> of the second fluid passageway <NUM> and the fourth heat exchanger <NUM> of the third fluid passageway <NUM> may operate at different times to switch the space between a freezer and a cooler, for example). From the fourth heat exchanger <NUM>, the working fluid may flow into the first header <NUM> where it is distributed to the suction lines <NUM> and the inlets <NUM> of the first compressors <NUM> to be compressed by the compression mechanisms <NUM> of the first compressors <NUM>.

The fourth fluid passageway <NUM> extends from the second header <NUM> to a fifth header <NUM>. The working fluid discharged from the first compressors <NUM> flows through the fourth fluid passageway <NUM> (via the discharge lines <NUM>) and into the fifth header <NUM> where it is distributed to intermediate pockets of the compression mechanisms <NUM> of the second compressors <NUM> (via vapor inlet lines <NUM> and vapor conduits <NUM>).

One of the benefits of the climate-control system <NUM> of the present disclosure is that the working fluid discharged from the first compressors <NUM> may be directed to the intermediate pockets of the compression mechanisms <NUM> of the second compressors <NUM> as oppose to mixing with the working fluid in the second fluid passageway <NUM> prior to the working fluid in the second fluid passageway <NUM> entering into the second compressors <NUM> (via the suction lines <NUM>). This improves system efficiency (e.g., by providing extra output or capacity of the compressors <NUM> and gaining system capacity through cooling of the working fluid in the intermediate pockets of the second compressors <NUM>) while at the same time avoiding having to size the suction lines <NUM> to account for the flow of the compressed working fluid exiting the first compressors <NUM>.

Another benefit of the climate-control system <NUM> of the present disclosure is that the working fluid exiting the vapor outlet <NUM> of the flash tank <NUM> may be directed to the intermediate pockets of the compression mechanisms <NUM> of the first compressors <NUM>, thereby improving system efficiency (e.g., by providing extra output or capacity of the first compressors <NUM> and gaining system capacity through cooling of the working fluid in the intermediate pockets of the first compressors <NUM>).

With reference to <FIG>, another climate-control system <NUM> is provided that may be generally similar to the climate-control systems <NUM>, <NUM> described above, apart from any exception noted below. The climate-control system <NUM> may include a first working-fluid circuit <NUM>, a second working-fluid circuit <NUM> and a first heat exchanger <NUM>. The first working-fluid circuit <NUM> and the second working-fluid circuit <NUM> may be in a heat transfer relationship (i.e., thermally coupled) with each other. The first working-fluid circuit <NUM> and the second working-fluid circuit <NUM> may also be fluidly isolated from each other.

The first working-fluid circuit <NUM> may include first compressors <NUM>, a second heat exchanger <NUM>, a third heat exchanger <NUM> and a first expansion device <NUM>. The structure and function of the first compressors <NUM> may be similar or identical to that of the second compressors <NUM>, <NUM> described above, and therefore, will not be described again in detail. The structure and function of the second heat exchanger <NUM> may be similar or identical to that of the first heat exchangers <NUM>, <NUM> described above, and therefore, will not be described again in detail. The structure and function of the third heat exchanger <NUM> may be similar or identical to that of the heat exchangers <NUM>,<NUM> described above, and therefore, will not be described again in detail. The structure and function of the first expansion device <NUM> may be similar or identical to that of the expansion devices <NUM>, <NUM> described above, and therefore, will not be described again in detail.

The first working-fluid circuit <NUM> may also include a first fluid passageway <NUM> and a second fluid passageway <NUM>. The first fluid passageway <NUM> extends from a first header <NUM> (that is in fluid communication with the first compressors <NUM> via discharge lines <NUM>) to a second header <NUM> (that is in fluid communication with the first compressors <NUM> via vapor inlet lines <NUM>). The first fluid passageway <NUM> includes the second heat exchanger <NUM>, the first expansion device <NUM> and a conduit <NUM> of the first heat exchanger <NUM>. The first header <NUM> may receive compressed first working fluid (e.g., R134a) from the discharge lines <NUM> and may direct the compressed first working fluid to the second heat exchanger <NUM>. The second heat exchanger <NUM> may transfer heat from the compressed first working fluid to ambient air that may be forced over the second heat exchanger <NUM> by a fan (not shown). In some configurations, the second heat exchanger <NUM> may transfer heat from the compressed first working fluid to a stream of liquid such as water, for example. From the second heat exchanger <NUM>, the first working fluid may flow through the first expansion device <NUM> where its temperature and pressure is lowered. The first working fluid then flows through the conduit <NUM> of the first heat exchanger <NUM> and to the second header <NUM> where the first working fluid is distributed to intermediate pockets of the compression mechanisms <NUM> of the first compressors <NUM> (via the vapor inlet lines <NUM> and vapor-injection conduits <NUM>).

The second fluid passageway <NUM> extends from the first fluid passageway <NUM> at a location between the second heat exchanger <NUM> and the first expansion device <NUM> and to a third header <NUM> (that is in fluid communication with the first compressors <NUM> via suction lines <NUM>). The second fluid passageway <NUM> includes a second expansion device <NUM> (e.g., an expansion valve or capillary tube) and the third heat exchanger <NUM>. A portion of the first working fluid downstream of the second heat exchanger <NUM> of the first fluid passageway <NUM> flows through the second expansion device <NUM> of the second fluid passageway <NUM> where its temperature and pressure is lowered. In the third heat exchanger <NUM>, the first working fluid may absorb heat from a first space to be cooled (e.g., an interior of a refrigerator, a refrigerated display case, or a cooler). From the third heat exchanger <NUM>, the first working fluid flows to the third header <NUM> where the first working fluid is distributed to the suction lines <NUM> and inlets <NUM> of the first compressors <NUM> to be compressed by the compression mechanisms <NUM> of the first compressors <NUM>.

The second working-fluid circuit <NUM> includes second compressors <NUM> and a fourth heat exchanger <NUM>. The structure and function of the second compressors <NUM> may be similar or identical to that of compressors <NUM> described above, and therefore, will not be described again in detail. The structure and function of the fourth heat exchanger <NUM> may be similar or identical to that of heat exchangers <NUM>, <NUM> described above, and therefore, will not be described again in detail.

The second working-fluid circuit <NUM> also includes a third expansion device <NUM> and a conduit <NUM> of the first heat exchanger <NUM>. A fourth header <NUM> (that is in fluid communication with the second compressors <NUM> via discharge lines <NUM>) may receive a compressed second working fluid (e.g., carbon dioxide) from the discharge lines <NUM> and may direct the compressed second working fluid to the conduit <NUM> of the first heat exchanger <NUM> where the second working fluid transfers heat to the first working fluid in the conduit <NUM>. The second working fluid then flows through the third expansion device <NUM> where its temperature and pressure is lowered. In the fourth heat exchanger <NUM>, the second working fluid may absorb heat from a second space to be cooled (e.g., freezer or a frozen food display case). From the fourth heat exchanger <NUM>, the second working fluid flows to a fifth header <NUM> where the second working fluid is distributed to suction lines <NUM> and inlets <NUM> the second compressors <NUM> to be compressed by the compression mechanisms <NUM> of the second compressors <NUM>.

One of the benefits of the climate-control system <NUM> of the present disclosure is that the first working fluid flowing through the conduit <NUM> of the first heat exchanger <NUM> may absorb heat from the second working-fluid circuit <NUM> prior to entering the intermediate pockets of the compression mechanisms <NUM> of the first compressors <NUM> (via the vapor inlet lines <NUM> and vapor-injection conduits <NUM>). This improves system efficiency (e.g., by providing extra output or capacity of the first compressors <NUM> and gaining system capacity through cooling of the working fluid in the intermediate pockets of the first compressors <NUM>).

With reference to <FIG>, another climate-control system <NUM> is provided that may be generally similar to the climate-control systems <NUM>, <NUM>, <NUM> described above, apart from any exception noted below. The climate-control system <NUM> may include a fluid-circuit having a first compressor <NUM>, a second compressor <NUM>, a first heat exchanger <NUM>, a second heat exchanger <NUM> and a third heat exchanger <NUM>. The structure and function of the first compressor <NUM> may be similar or identical to that of the compressors <NUM>, <NUM> described above, and therefore, will not be described again in detail. The structure and function of the second compressor <NUM> may be similar or identical to that of compressors <NUM>, <NUM>, <NUM> described above, and therefore, will not be described again in detail. The structure and function of the first heat exchanger <NUM> may be similar or identical to that of heat exchangers <NUM>, <NUM>, <NUM> described above, and therefore, will not be described again in detail. The structure and function of the second heat exchanger <NUM> may be similar or identical to that of heat exchangers <NUM>, <NUM>, <NUM> described above, and therefore, will not be described again in detail. The structure and function of the third heat exchanger <NUM> may be similar or identical to that of heat exchangers <NUM>, <NUM>, <NUM> described above, and therefore, will not be described again in detail.

The climate-control system <NUM> also includes a first fluid passageway <NUM>, a vapor inlet line <NUM> and a second fluid passageway <NUM>. The first fluid passageway <NUM> extends from a discharge line <NUM> of the first compressor <NUM> to an inlet <NUM> of a <NUM>-way valve <NUM>. The vapor inlet line <NUM> extends from a first outlet <NUM> of the <NUM>-way valve <NUM> to intermediate pockets of a compression mechanism <NUM> of the second compressor <NUM> (via a vapor-injection conduit <NUM>). The second fluid passageway <NUM> extends from a second outlet <NUM> of the <NUM>-way valve <NUM> to a suction line <NUM> of the second compressor <NUM>.

Compressed working fluid discharged from the first compressor <NUM> may flow to the inlet <NUM> of the <NUM>-way valve <NUM>. If the climate-control system <NUM> does not have a medium temperature load (i.e., the climate-control system <NUM> does not require the second heat exchanger <NUM> to absorb heat from a space to be cooled), for example, the working fluid flowing through the <NUM>-way valve <NUM> is directed out the second outlet <NUM> of the <NUM>-way valve <NUM> to the suction line <NUM> of the second compressor <NUM> to be compressed by the compression mechanism <NUM> of the second compressor <NUM>. In this way, the second compressor <NUM> acts as a second-stage pump, for example, to circulate the working fluid through the fluid-circuit of the climate-control system <NUM>. A check valve <NUM> may be disposed along a third fluid passageway <NUM> extending from the second heat exchanger <NUM> to the suction line <NUM> to prevent back-flow into the second heat exchanger <NUM>.

If the climate-control system <NUM> does have a medium temperature load (e.g., the climate-control system <NUM> requires the second heat exchanger <NUM> to absorb heat from the space to be cooled), the working fluid flowing through the inlet <NUM> of the <NUM>-way valve <NUM> is directed out the first outlet <NUM> of the <NUM>-way valve <NUM> to the vapor inlet line <NUM> where it flows to intermediate pockets of the compression mechanism <NUM> of the second compressor <NUM> (via the vapor-injection conduit <NUM>).

One of the benefits of the climate-control system <NUM> of the present disclosure is that the compressed working fluid discharged from the first compressor <NUM> may flow to the suction line <NUM> of the second compressor <NUM> or the intermediate pockets of the compression mechanism <NUM> of the second compressor <NUM> based at least partially on the operating conditions of the climate-control system <NUM>. In this way, the efficiency of the climate-control system <NUM> may be optimized. It is understood that the climate-control systems <NUM>, <NUM>, <NUM> described above may be modified to incorporate the climate-control system <NUM> thereto.

With reference to <FIG>, another climate-control system <NUM> is provided that may be generally similar to the climate-control systems <NUM>, <NUM>, <NUM>, <NUM> described above, apart from any exception noted below. The climate-control system <NUM> may have a fluid-circuit having a first compressor <NUM>, a second compressor <NUM>, a first heat exchanger <NUM>, a second heat exchanger <NUM> and a third heat exchanger <NUM>. The structure and function of the first compressor <NUM> may be similar or identical to that of the compressors <NUM>, <NUM>, <NUM> described above, and therefore, will not be described again in detail. The structure and function of the second compressor <NUM> may be similar or identical to that of compressors <NUM>, <NUM>, <NUM>, <NUM> described above, and therefore, will not be described again in detail. The structure and function of the first heat exchanger <NUM> may be similar or identical to that of heat exchangers <NUM>, <NUM>, <NUM>, <NUM> described above, and therefore, will not be described again in detail. The structure and function of the second heat exchanger <NUM> may be similar or identical to that of heat exchangers <NUM>, <NUM>, <NUM>, <NUM> described above, and therefore, will not be described again in detail. The structure and function of the third heat exchanger <NUM> may be similar or identical to that of heat exchangers <NUM>, <NUM>, <NUM>, <NUM> described above, and therefore, will not be described again in detail.

The climate-control system <NUM> may also include a first fluid passageway <NUM>, a vapor inlet line <NUM> and a second fluid passageway <NUM>. The first fluid passageway <NUM> extends from a discharge line <NUM> of the first compressor <NUM> to a third fluid passageway <NUM> (that extends from a discharge line <NUM> of the second compressor <NUM> and includes the first heat exchanger <NUM>). The first fluid passageway <NUM> may include first and second <NUM>-way valves <NUM>, <NUM>. The vapor inlet line <NUM> extends from a first outlet <NUM> of the first <NUM>-way valve <NUM> to intermediate pockets of a compression mechanism <NUM> of the second compressor <NUM> (via a vapor-injection conduit <NUM>). The second fluid passageway <NUM> extends from a first outlet <NUM> of the second <NUM>-way valve <NUM> to a suction line <NUM> of the second compressor <NUM>.

Compressed working fluid discharged from the first compressor <NUM> may flow to an inlet <NUM> of the second <NUM>-way valve <NUM>. If the climate-control system <NUM> does not have a medium-temperature load (e.g., the climate-control system <NUM> does not require the second heat exchanger <NUM> to absorb heat from a space to be cooled), the working fluid flowing through the inlet <NUM> of the second <NUM>-way valve <NUM> is directed out the first outlet <NUM> of the second <NUM>-way valve <NUM> to the suction line <NUM> of the second compressor <NUM> to be compressed by the compression mechanism <NUM> of the second compressor <NUM>. In this way, the second compressor <NUM> may act as a second-stage pump, for example, to circulate the working fluid through the fluid-circuit of the climate-control system <NUM>. A check valve <NUM> may be disposed along a fourth fluid passageway <NUM> extending from the second heat exchanger <NUM> to the suction line <NUM> to prevent back-flow into the second heat exchanger <NUM>.

If the climate-control system <NUM> does have a medium temperature load (e.g., the climate-control system <NUM> requires the second heat exchanger <NUM> to absorb heat from the space to be cooled), the working fluid flowing through the inlet <NUM> of the second <NUM>-way valve <NUM> is directed out a second outlet <NUM> of the second <NUM>-way valve <NUM> and into an inlet <NUM> of the first <NUM>-way valve <NUM>. The working fluid may then be directed out the first outlet <NUM> of the first <NUM>-way valve <NUM> to the vapor inlet line <NUM> where it flows to intermediate pockets of the compression mechanism <NUM> of the second compressor <NUM> (via the vapor-injection conduit <NUM>).

In some configurations, the climate-control system <NUM> may not have a medium-temperature load, for example, and the second compressor <NUM> of the climate-control system <NUM> may be shut-off, therefore, not being used as a second-stage pump, for example, to circulate the working fluid through the fluid-circuit. In this way, the compressed working fluid discharged from the first compressor <NUM> may bypass the second compressor <NUM>. That is, the compressed working fluid discharged from the first compressor <NUM> may flow to the second <NUM>-way valve <NUM> where it is directed out the second outlet <NUM> of the second <NUM>-way valve <NUM> and into the inlet <NUM> of the first <NUM>-way valve <NUM>. The working fluid may then be directed to a second outlet <NUM> of the first <NUM>-way valve <NUM> where it may flow to the first heat exchanger <NUM> (via the third fluid passageway <NUM>).

One of the benefits of the climate-control system <NUM> of the present disclosure is that the compressed working fluid discharged from the first compressor <NUM> may flow to the suction line <NUM> of the second compressor <NUM> or the intermediate pockets of the compression mechanism <NUM> of the second compressor <NUM> based at least partially on the operating conditions of the climate-control system <NUM>. Another benefit of the climate-control system <NUM> of the present disclosure is that the working fluid may bypass the second compressor <NUM> based at least partially on the operating conditions of the climate-control system <NUM>. In this way, the efficiency of the climate-control system <NUM> may be optimized. It is understood that the climate-control systems <NUM>, <NUM>, <NUM>, <NUM> described above may be modified to incorporate the climate-control system <NUM> thereto.

In this application, the term "module" or "control module" may be replaced with the term circuit. The term "module" may refer to, be part of, or include an Application Specific Integrated Circuit (ASIC); a digital, analog, or mixed analog/digital discrete circuit; a digital, analog, or mixed analog/digital integrated circuit; a combinational logic circuit; a field programmable gate array (FPGA); a processor (shared, dedicated, or group) that executes code; memory (shared, dedicated, or group) that stores code executed by a processor; other suitable hardware components that provide the described functionality; or a combination of some or all of the above, such as in a system-on-chip.

The term memory circuit is a subset of the term computer-readable medium. The term computer-readable medium, as used herein, does not encompass transitory electrical or electromagnetic signals propagating through a medium (such as on a carrier wave); the term computer-readable medium may therefore be considered tangible and non-transitory. Non-limiting examples of a non-transitory, tangible computer-readable medium are nonvolatile memory circuits (such as a flash memory circuit, an erasable programmable read-only memory circuit, or a mask read-only memory circuit), volatile memory circuits (such as a static random access memory circuit or a dynamic random access memory circuit), magnetic storage media (such as an analog or digital magnetic tape or a hard disk drive), and optical storage media (such as a CD, a DVD, or a Blu-ray Disc).

In this application, apparatus elements described as having particular attributes or performing particular operations are specifically configured to have those particular attributes and perform those particular operations. Specifically, a description of an element to perform an action means that the element is configured to perform the action. The configuration of an element may include programming of the element, such as by encoding instructions on a non-transitory, tangible computer-readable medium associated with the element.

The apparatuses and methods described in this application may be partially or fully implemented by a special purpose computer created by configuring a general purpose computer to execute one or more particular functions embodied in computer programs. The functional blocks, flowchart components, and other elements described above serve as software specifications, which can be translated into the computer programs by the routine work of a skilled technician or programmer.

The computer programs include processor-executable instructions that are stored on at least one non-transitory, tangible computer-readable medium. The computer programs may also include or rely on stored data. The computer programs may encompass a basic input/output system (BIOS) that interacts with hardware of the special purpose computer, device drivers that interact with particular devices of the special purpose computer, one or more operating systems, user applications, background services, background applications, etc..

The computer programs may include: (i) descriptive text to be parsed, such as HTML (hypertext markup language), XML (extensible markup language), or JSON (JavaScript Object Notation) (ii) assembly code, (iii) object code generated from source code by a compiler, (iv) source code for execution by an interpreter, (v) source code for compilation and execution by a just-in-time compiler, etc. As examples only, source code may be written using syntax from languages including C, C++, C#, Objective-C, Swift, Haskell, Go, SQL, R, Lisp, Java®, Fortran, Perl, Pascal, Curl, OCaml, Javascript®, HTML5 (Hypertext Markup Language 5th revision), Ada, ASP (Active Server Pages), PHP (PHP: Hypertext Preprocessor), Scala, Eiffel, Smalltalk, Erlang, Ruby, Flash®, Visual Basic®, Lua, MATLAB, SIMULINK, and Python®.

Claim 1:
A climate-control system (<NUM>) comprising:
a first compressor (<NUM>) having a first inlet (<NUM>) and a first outlet (<NUM>);
a second compressor (<NUM>) in fluid communication with the first compressor (<NUM>) and having second and third inlets (<NUM>, <NUM>), a second compression mechanism (<NUM>) and a second outlet (<NUM>), the second and third inlets (<NUM>, <NUM>) fluidly coupled to the second compression mechanism (<NUM>), the second compression mechanism configured to receive working fluid from the first compressor (<NUM>) through the third inlet (<NUM>) and is configured to discharge working fluid through the second outlet (<NUM>) of the second compressor (<NUM>),
wherein a first heat exchanger (<NUM>) is in fluid communication with the second compressor (<NUM>) and is configured to receive working fluid from the second compressor (<NUM>),
wherein a second heat exchanger (<NUM>) is in fluid communication with the first heat exchanger (<NUM>) and includes a fourth inlet (<NUM>) and third and fourth outlets (<NUM>, <NUM>), the fourth inlet (<NUM>) receives working fluid from the first heat exchanger (<NUM>), the third outlet (<NUM>) provides working fluid to the first inlet (<NUM>),
wherein a first expansion device (<NUM>) is disposed between the first heat exchanger (<NUM>) and the second heat exchanger (<NUM>),
wherein the fourth outlet (<NUM>) of the second heat exchanger (<NUM>) provides working fluid to the second inlet (<NUM>) of the second compressor (<NUM>), and
wherein the climate-control system (<NUM>) further comprises a third heat exchanger (<NUM>) characterized in that the third heat exchanger (<NUM>) is disposed between the first and second compressors (<NUM>, <NUM>) and including a fifth inlet a fifth outlet providing working fluid to the second inlet (<NUM>) of the second compressor (<NUM>), and a sixth outlet providing working fluid to the third inlet (<NUM>) of the second compressor (<NUM>).