Air system

An air system includes an enclosure. A compressor, a first energy exchange device, an expansion device, and a second energy exchange device are each positioned in or along the enclosure and connected in a closed refrigerant loop. A first inlet receives air being psychrometrically controlled in the enclosure from a first source. A first outlet removes the psychrometrically controlled air from the enclosure. A second inlet receives air being non-psychrometrically controlled in the enclosure from a second source. A second outlet removes the non-psychrometrically controlled air from the enclosure. A third energy exchange device positioned in or along the enclosure exchanges energy between the psychrometrically controlled air and the non-psychrometrically controlled air. The enclosure is adapted for insertion through an opening having opposed parallel sides having a dimension of 36 inches or less.

FIELD OF THE INVENTION

The present invention is directed to the field of air systems for heating, ventilating, and/or air-conditioning (HVAC) system, and, in particular, for dedicated outdoor air systems.

BACKGROUND OF THE INVENTION

It is known that the air outside of buildings is generally healthier for human respiration than the air inside of buildings. But humans are most comfortable in somewhat neutral air conditions of temperature and humidity that are not found in the outside environment in which humans choose to live. It is possible to introduce or duct in outside air to the inside of a building or enclosure, with energy then needing to be expended to condition the air to the proper temperature and humidity. Based on the amount and type of human activity, more or less outside air is required to satisfy the ventilation need. To solve this problem, the HVAC market has responded with modifications of traditional equipment meant to recondition recirculated indoor air. These solutions are either packaged (self-contained) and large (both cabinet volume and footprint) for a particular quantity of air being conditioned and/or the amount of energy being removed from the air for cooling or added to the air for heating, and require exterior mounting, such as on a roof, or if they are smaller, containing components that are meant to use less interior building volume/space but split, needing separate remotely located components that require field layout and connections. Due to traditional manufacturing processes, these units are assembled in such a way that one of the major serviceable components, such as a compressor, requires skilled labor in a fire-hazard situation to be serviced. To improve the overall safety of this process, various codes have been developed to require certain protocols be followed. Compliance with these codes may require what is sometimes referred to as a “hot work permit.” For example, when working on a compressor in a municipal building, the permit might require the presence of two knowledgeable persons, with a fire extinguisher, including appropriate documentation as to the day and time of work. Another problem is that the outside conditions change with time and location. There is a benefit in having the HVAC equipment handling this ventilation air to be able to adapt in some way to changes in some combination of input conditions and customer requirements, and be able to measure, with some reasonable accuracy, the amount of air being brought into the equipment. At the same time, a combination of various efficiency codes has been developed to aid in standardizing and enforcing the commercial HVAC market's response to the outside air ventilation need. Similar to miles-per-gallon for automobiles, these metrics aim to make equipment produce a certain beneficial effect with minimal energy use. Lastly, having that same piece of equipment both heat the incoming air in winter and cool the incoming air in summer without auxiliary inputs, such as electric heaters, has been a problem for some time, as the outside air has a much larger swing in temperature than the air that stays in the building.

There is a need in the art for an air system that does not suffer from these deficiencies.

SUMMARY OF THE INVENTION

In an embodiment, an air system includes an enclosure. The air system further includes a compressor, a first energy exchange device, an expansion device, and a second energy exchange device each positioned in or along the enclosure and connected in a closed refrigerant loop. The air system further includes a first inlet formed in the enclosure for receiving air from a first source, the air received from the first source being psychrometrically controlled in the enclosure. The air system further includes a first outlet formed in the enclosure for removing the psychrometrically controlled air from the enclosure. The air system further includes a second inlet formed in the enclosure for receiving air from a second source, the air received from the second source being non-psychrometrically controlled in the enclosure. The air system further includes a second outlet formed in the enclosure for removing the non-psychrometrically controlled air from the enclosure. The air system further includes a third energy exchange device positioned in or along the enclosure for exchanging energy between the psychrometrically controlled air and the non-psychrometrically controlled air. The enclosure is adapted for insertion through an opening having opposed parallel sides having a dimension of 36 inches or less.

In another embodiment, an air system includes an enclosure. The air system further includes a compressor, a first energy exchange device, an expansion device, and a second energy exchange device each positioned in or along the enclosure and connected in a closed refrigerant loop. The air system further includes a first inlet formed in the enclosure for receiving air from a first source, the air received from the first source being psychrometrically controlled in the enclosure. The air system further includes a first outlet formed in the enclosure for removing the psychrometrically controlled air from the enclosure. The air system further includes a second inlet formed in the enclosure for receiving air from a second source, the air received from the second source being non-psychrometrically controlled in the enclosure. The air system further includes a second outlet formed in the enclosure for removing the non-psychrometrically controlled air from the enclosure. The air system further includes a third energy exchange device positioned in or along the enclosure for exchanging energy between the psychrometrically controlled air and the non-psychrometrically controlled air. The air system further includes the enclosure having a cross section having outside dimensions of less than 36 inches in two perpendicular directions.

In a further embodiment, a compressor includes a first fitting connected to a first pressure port of the compressor or to one end of a first tube connected to the first pressure port, and a second fitting connected to a second pressure port of the compressor or to one end of a second tube connected to the second pressure port. The compressor further includes the first fitting and the second fitting being threadedly engageable with a corresponding first fitting to form a first fitting pair, and a second fitting pair, respectively, the corresponding first fitting and corresponding second fitting being in fluid communication with a closed refrigerant loop, the first fittings of the first fitting pair and the second fittings of the second fitting pair each being adapted to be repeatably threadedly disconnected from one another. In response to each instance of the first fitting and the corresponding first fitting of the first fitting pair and the second fitting and the corresponding second fitting of the second fitting pair being threadedly disconnected from one another, each first fitting, corresponding first fitting, second fitting, and corresponding second fitting forming a fluid tight seal preventing refrigerant flow therethrough.

Other features and advantages of the present invention will be apparent from the following more detailed description, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention. Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present application. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are typically not depicted in order to facilitate a less obstructed view of these various embodiments of the present application.

DETAILED DESCRIPTION OF THE INVENTION

As shown inFIG. 1, an exemplary embodiment an air system10of the present invention is both small and packaged (self-contained), meaning that it is, without disassembly, able to be moved through or adapted for insertion through opening12such as standard doorways having a door14, which doorways having opposed parallel sides16and installed inside of buildings in, for example, drop-ceilings, rather than on a roof. In one embodiment, the air system may be configured for outdoor installation. Stated another way, air system10that includes components secured in or along a unit or enclosure22, without disassembly, is sufficiently compact for insertion through openings12having opposed parallel sides16separated by or having a dimension18of 36 inches or less.

This compact construction is especially beneficial for buildings with minimal roof space, such as high-rise buildings. This unit or air system10is also packaged. That is, an installer does not need to layout and field assemble different components, such as field refrigerant lines or tubes extending between sections, typically involving two electrical hook-ups, two condensation hook-ups, and/or two separate installations (e.g., removing ceiling tiles, etc.) for a conventional unit having separately located condenser and evaporator sections, sometimes referred to as a “split” unit. Another solution this air system10offers is that the major serviceable component, such as a compressor20is replaceable without needing a “hot work permit.” This is accomplished by a specific piping layout with valves that manages or controls the flow of refrigerant. The air flow measurement conundrum is solved via utilizing a physical phenomenon of the air through a certain device within the cabinet or enclosure that allows the air flow to be easily and accurately correlated with simple tools commonly carried by field technicians, or, alternatively, measured and controlled by building management systems. The efficiency problem is solved in part by the arrangement of devices within the unit or air system, the order of which the air must pass through, and refrigeration management using certain valves and thermodynamic processes utilized in vapor compression refrigeration systems. This also allows the unit or air system to heat and cool incoming outside air without the need for auxiliary heating devices over a wider range of natural conditions compared to other air systems presently in the market.

As shown inFIG. 1, air system10includes a compact enclosure22having outside or exterior dimensions24,26,28extending in mutually perpendicular directions. In one embodiment, at least one of outside or exterior dimensions24,26,28may not extend perpendicularly relative to the direction of at least one of the other dimensions. In other words, in one embodiment, enclosure22may have any shape. In one embodiment, dimension24measures 36 inches or less in length. In one embodiment, dimensions24,26each measure 36 inches or less in length. In one embodiment, dimensions24,26each measure less than 36 inches in length. In one embodiment, dimensions24,26each measure 36 inches or less in length and are mutually perpendicular to one another. As shown inFIG. 2, enclosure22includes an inlet30for receiving air36to be psychrometrically controlled from an air source34, which air36being removed from enclosure22via an outlet32. Enclosure22further includes an inlet38for receiving air44that is non-psychrometrically controlled from an air source42, which air44being removed from enclosure22via an outlet40.

For purposes herein, the term “psychrometrically controlled” means that parameters such as humidity and temperature are to be controlled for air36, for purposes such as being introduced in a structure (not shown) for climate control within the structure. That is, the humidity and temperature of air36exiting enclosure22via the outlet32is controlled more tightly compared to the range of humidity and temperature of air36of air entering enclosure22from source34.

For purposes herein, the term “non-psychrometrically controlled” means that parameters such as humidity and temperature are not to be controlled. That is, although air44is utilized to exchange energy or energy and moisture with air36, it is not an object of the invention to control the humidity or the temperature of air44exiting enclosure22via outlet40, but for air system10to efficiently exchange energy or energy and moisture between air44with air36so that air36exits enclosure22via outlet32at a desired humidity and temperature.

For purposes herein, the terms “psychrometrically controlled air36” and “air36” and the like may be used interchangeably.

For purposes herein, the terms “non-psychrometrically controlled air44” and “air44” and the like may be used interchangeably.

It is to be understood that components, including refrigerant lines or tubes deliverable as part of the assembled enclosure may be secured in or along enclosure22, such as extending along the exterior of the enclosure, such as extending outside of the enclosure dimensions24,26,28, so long as enclosure22may be inserted through opening12(FIG. 1) without requiring disassembly of these components from the enclosure prior to such insertion.

As further shown inFIG. 2, psychrometrically controlled air36enters enclosure22via inlet30and non-psychrometrically controlled air44enters enclosure22via inlet38in a direction opposite psychrometrically controlled air36. The counterflowing streams of psychrometrically controlled air36and non-psychrometrically controlled air44exchange energy in energy exchange device46. In one embodiment, energy exchange device46is an energy recovery wheel such as a sensible wheel, for exchanging sensible energy as a result of the temperature differences between the wheel and the air36,44flowing through the wheel. If the wheel is coated with a desiccant material, defining an enthalpy wheel, latent energy may also be exchanged between psychrometrically controlled air36and non-psychrometrically controlled air44. Therefore, in one embodiment, energy exchange device46may exchange both sensible and latent energy, such as with an enthalpy wheel, and in another embodiment, energy exchange device46may exchange only sensible energy, such as with a sensible wheel. In one embodiment, energy exchange device is a heat pipe.FIG. 3shows an embodiment of air system10that is similar toFIGS. 1 and 2, but permits installation in a different orientation, such as dimension28. That is, the air system10arrangement shown inFIGS. 1 and 2are configured such that dimension28extends in a vertical direction, while inFIG. 3, dimension28extends in a horizontal direction, e.g., installation in a drop-ceiling. In one embodiment, air system10may be configured such that dimension28extends in any direction between vertical and horizontal.

As further shown inFIG. 2, optionally, one or more sensors48measure the pressure drop or difference through energy exchange device46for each of psychrometrically controlled air36and non-psychrometrically controlled air44, outputting an output voltage in a well-known manner. A. For example, a single sensor48, such as a diaphragm sensor directly measures the pressure difference between two predetermined locations of air36or air44relative to energy exchange device46, versus at least two sensors48, in which each sensor48of the at least two sensors48measures a pressure at a predetermined location of air36or air44relative to energy exchange device46, from which a pressure difference is calculated. The output voltage may be measured by a technician with conventional instruments, such as a voltmeter. There is a known relationship in the form of a curve50(FIG. 7) between flow rate (CFM) and the output voltage that may be provided graphically and accessible to the technician, e.g., positioned on an inside surface of a panel (not shown) of enclosure22. For example, for a single sensor48, the voltage signal is representative of a flow rate (CFM) of air36or air44, versus at least two sensors48, in which each sensor48of the at least two sensors48outputs a voltage signal from which a voltage difference is calculated and from which a flow rate of air36or air44is then calculated. With this information, a technician can easily independently adjust or selectively control the flow rate (CFM) of psychrometrically controlled air36and non-psychrometrically controlled air44in enclosure22by adjusting the speed of an associated turbomachine52dedicated for use with each of air36,44for increasing the pressure of the air36,44until the output voltage corresponding to the desired flow rate (CFM) is achieved.

For purposes of illustration, if a desired flow rate is 350 CFM, a technician (not shown) utilizing curve50(FIG. 7) would note that 350 CFM corresponds to a sensor48output voltage (or a sensor48output voltage difference, if at least two sensors48are utilized) of approximately 3.9 V. With air system10operating, the technician would attach a voltmeter to leads in the control panel (not shown) corresponding to sensor(s)48and adjust the speed of the associated turbomachine52, such as by adjusting the input voltage to the turbomachine52, until the voltmeter indicates 3.9 V. This capability results in significant time savings for the technician during an installation. In one embodiment, as shown inFIG. 7, curve50is linear, corresponding to a laminar flow regime of air36,44, more easily permitting a technician to correlate a flow rate (CFM) from an output voltage. In one embodiment, curve50may be non-linear, correlating to a non-laminar flow regime of air36,44. While an exemplary range of flow rate between 100 and 500 CFM and voltage values between 1.0 and 7.0 V are depicted inFIG. 7, these ranges are not intended to be limiting.

It is to be understood that while only one curve50is shown inFIG. 7, in one embodiment, two separate and independent curves may be utilized if the corresponding relationships between flow rate (CFM) and the output voltage of psychrometrically controlled air36and non-psychrometrically controlled air44are different from one another.

In one embodiment, the sensor output voltage is directly accessible via a display (not shown), not requiring a technician to carry a voltmeter to measure the sensor output voltage, also permitting independent flow rate (CFM) adjustability of each of psychrometrically controlled air36and non-psychrometrically controlled air44in enclosure22. In one embodiment, a well known microprocessor control system11calculates and directly displays flow rate (CFM), also permitting independent flow rate (CFM) adjustability of each of psychrometrically controlled air36and non-psychrometrically controlled air44in enclosure22.

Referring back toFIG. 2, once psychrometrically controlled air36enters enclosure22via inlet30and non-psychrometrically controlled air44enters enclosure22via inlet38in a direction opposite psychrometrically controlled air36and exchange energy in energy exchange device46, non-psychrometrically controlled air44is directed by turbomachine52to exchange energy with energy exchange device54for exchanging energy with closed refrigerant loop70(FIG. 4) before exiting or being removed from enclosure22. In one embodiment, turbomachine52may be positioned anywhere along the flow path of non-psychrometrically controlled air44between inlet38, energy exchange device46, energy exchange device54, and outlet40, including being at least partially exterior of enclosure22, such as extending exterior of enclosure22near inlet38or outlet40, so long as such positioning does not require disassembly of turbomachine52from enclosure22in order to permit insertion of enclosure22through opening12(FIG. 1) as previously discussed.

As further shown inFIG. 2, once psychrometrically controlled air36enters enclosure22via inlet30and non-psychrometrically controlled air44enters enclosure22via inlet38in a direction opposite psychrometrically controlled air36and exchange energy in energy exchange device46, psychrometrically controlled air36is directed by turbomachine52to flow into a compartment56positioned upstream of an energy exchange device60and then through a region58of energy exchange device60defining a first pass62through energy exchange device60. In one embodiment, energy exchange device60is positioned in or along enclosure22. After completing first pass62, psychrometrically controlled air36exits energy exchange device through a region64, entering a compartment66that directs psychrometrically controlled air36through an energy exchange device68for exchanging energy with refrigerant loop70(FIG. 4) before re-entering energy exchange device60through a region72defining a second pass74through energy exchange device60. As a result, energy is non-mixingly exchanged between first pass62and second pass74of the psychrometrically controlled air36flowing through energy exchange device60. After completing second pass74, psychrometrically controlled air36exits energy exchange device60through a region76, entering a compartment78that directs psychrometrically controlled air36through an energy exchange device80for exchanging energy with refrigerant loop70(FIG. 4) before psychrometrically controlled air36exits enclosure22via outlet32. In one embodiment, energy exchange device80is positioned in or along enclosure22.

In one embodiment, turbomachine52may be positioned anywhere along the flow path of psychrometrically controlled air36between inlet30, energy exchange device46, energy exchange device60, energy exchange device68, energy exchange device80and outlet32, including being at least partially exterior of enclosure22, such as extending exterior of enclosure22near inlet30or outlet32, so long as such positioning does not require disassembly of turbomachine52from enclosure22in order to permit insertion of enclosure22through opening12(FIG. 1) as previously discussed.

FIG. 4is a diagram of an exemplary closed refrigerant loop70for use in the air system10(FIG. 1). Components, such as refrigerant service ports82, expansion device(s)104, and check valves106are shown inFIG. 4, but not further discussed herein unless pertinent to the invention. Compressor20compresses a refrigerant vapor and delivers the vapor from a port84through a tube86that is threadedly engaged with a fitting88at an end of tube86opposite port84. A tube90extends between a reversing valve92at one end of tube90to a fitting94that is threadedly engaged at an opposite end of tube90. The ends of facing or corresponding fittings88,94when threadedly engaged form a fitting pair96. Compressor20can be any suitable type of compressor, e.g., centrifugal compressor, reciprocating compressor, screw compressor, scroll compressor, etc. When operating to provide cooling to psychrometrically controlled air36(FIG. 2), reversing valve92is configured to deliver refrigerant through tube98to energy exchange device54, operating as a condenser in the cooling mode for exchanging energy with non-psychrometrically controlled air44(FIG. 2). The flow path of refrigerant for providing cooling to psychrometrically controlled air36is shown by directional arrows100, and the flow path of refrigerant for providing heating to psychrometrically controlled air36is shown by directional arrows102.

Returning toFIG. 4for operation of refrigerant loop70in cooling mode, once refrigerant has flowed through energy exchange device54for exchanging energy with non-psychrometrically controlled air44(FIG. 2) and is at least partially condensed, the at least partially condensed refrigerant flows through tube108before flowing through optional vessel110, sometimes referred to as a liquid receiver. After flowing through vessel110, refrigerant flows through tube112and then through an optional (in cooling mode) energy exchange device80, sometimes referred to as a reheat coil, for exchanging energy with second pass74(FIG. 2) psychrometrically controlled air36(FIG. 2) flowing through energy exchange device60. After flowing through energy exchange device80, refrigerant then flows through expansion device104which greatly lowers the temperature and pressure of the refrigerant before entering energy exchange device68, sometimes referred to as an evaporator. Refrigerant exchanges energy with first pass62psychrometrically controlled air36(FIG. 2) flowing around energy exchange device68, becoming vapor refrigerant that flows through tube116to reversing valve92, and then flows through an optional vessel118, sometimes referred to as an accumulator. The vapor refrigerant then flows from vessel118through tube120that is threadedly engaged with a fitting94at an end of tube120opposite vessel118. A tube122extends between an optional filter124at one end of tube122to a fitting88that is threadedly engaged at an opposite end of tube122. The ends of facing or corresponding fittings88,94when threadedly engaged form a fitting pair97. The vapor refrigerant then flows from filter124through a tube126, returning the vapor refrigerant to a port130of compressor20to complete the refrigerant loop70.

Returning toFIG. 4, operation of refrigerant loop70in a heating mode is now discussed, beginning at reversing valve92. That is, when reversing valve92is operating to provide heating to psychrometrically controlled air36(FIG. 2), reversing valve92is configured to deliver refrigerant received from tube90to tube116to energy exchange device68, operating as a condenser in the heating mode for exchanging energy with first pass62psychrometrically controlled air36(FIG. 2). In one embodiment, optional check valve106positioned in fluid communication between the tubes114,116results in a portion of vapor refrigerant bypassing energy exchange device68, which further results in energy exchange device80receiving superheated refrigerant for exchanging energy with second pass74psychrometrically controlled air36, requiring energy exchange device80to essentially become responsible for condensing the refrigerant, raising the condensing pressure compared to what the condensing pressure would have been if energy exchange device68had been utilized to condense the refrigerant, which occurs in a conventional heat pump construction. By virtue of utilizing check valve106and energy exchange device80as described above, energy exchange device80operates to additionally cool the refrigerant when operating in cooling mode, thereby improving efficiency, while operating within acceptable limits of the components in heating mode. After refrigerant flows through energy exchange device80for exchanging energy with second pass74psychrometrically controlled air36(FIG. 2), the refrigerant flows through tube112to vessel110and then through tube108to expansion device104and to energy exchange device54operating as an evaporator in heating mode for exchanging energy with non-psychrometrically controlled air44(FIG. 2) before returning the vapor refrigerant through tube98to reversing valve92. After flowing through reversing valve92, the vapor refrigerant then flows through vessel118. The vapor refrigerant then flows from vessel118through tube120that is threadedly engaged with a fitting94at an end of tube120opposite vessel118. Tube122extends between an optional filter124at one end of tube122to fitting88that is threadedly engaged at an opposite end of tube122. The ends of facing or corresponding fittings88,94when threadedly engaged form fitting pair97. The vapor refrigerant then flows from filter124through tube126, returning the vapor refrigerant to port130of compressor20to complete the refrigerant loop70.

In one embodiment, energy exchange device60may be a heat pipe.

In one embodiment, a single expansion device104may be utilized for use with both energy exchange devices54,68.

In one embodiment, air system10(FIG. 2) may be configured to operate in three different operating modes:

1. Ventilating (turbomachines52(FIG. 2)) with simultaneous energy recovery via energy exchange device46(with compressor20(FIG. 2) as well as associated energy exchange devices54,68,80(FIG. 2) being non-functional);

2. Ventilating (turbomachines52(FIG. 2)) with simultaneous energy recovery via energy exchange device46and simultaneous dehumidification as a result of refrigerant flow in refrigerant loop70(FIG. 4) in directional arrow100(FIG. 4);

3. Ventilating (turbomachines52(FIG. 2)) with simultaneous energy recovery via energy exchange device46and simultaneous heating as a result of refrigerant flow in refrigerant loop70(FIG. 4) directional arrow102(FIG. 4).

In one embodiment, air system10(FIG. 2) may be configured to operate in less than the three different operating modes, depending upon the application, permitting removal of mode-specific components not used.

FIG. 8shows a psychrometric chart at sea level at a barometric pressure of 29.921 inches of mercury for an exemplary air source34(FIG. 2) received and processed by an exemplary air system of the present invention. That is, air source34(FIG. 2) may be received by the air system in any combination of dry bulb temperatures between 0-103° F. and between 30-100 percent relative humidity as encompassed by region ABGH. Within region ABGH are subregions EFGH, CDEF, and ABCD. Conditions for air source42(FIG. 2) are 75° F. dry bulb/62.5° F. wet bulb for cooling, and 70° F. dry bulb/58.5° F. wet bulb for heating. It is to be understood that information contained inFIG. 8are exemplary and not intended to be limiting. For example, the air system of the present invention will still function for air source34(FIG. 2) ranges below 0° F. and above 103° F.

As further shown inFIG. 8, when air source34is provided to the air system from subregion EFGH, the air system is in operating mode3(see above), with the air system delivering psychrometrically controlled air36(FIG. 2) from outlet32(FIG. 2) encompassed by the subregion having a cross-hatched region identified as “Heating w/Compressor and Energy Recovery Wheel.”

As further shown inFIG. 8, when air source34is provided to the air system from subregion ABCD, the air system is in operating mode2(see above), with the air system delivering psychrometrically controlled air36(FIG. 2) from outlet32(FIG. 2) encompassed by the subregion having a cross-hatched region identified as “Cooling w/Compressor and Energy Recovery Wheel.”

As further shown inFIG. 8, when air source34is provided to the air system from subregion CDEF, the air system is in operating mode1(see above, for cooling), with the air system delivering psychrometrically controlled air36(FIG. 2) from outlet32(FIG. 2) encompassed by the subregion having a cross-hatched region identified as “Cooling with Energy Recovery Wheel Only”.

As further shown inFIG. 8, when air source34is provided to the air system from subregion CDEF, the air system is in operating mode1(see above, for heating), with the air system delivering psychrometrically controlled air36(FIG. 2) from outlet32(FIG. 2) encompassed by the subregion having a cross-hatched region identified as “Heating with Energy Recovery Wheel Only.”

Returning toFIG. 2, the four cross-hatched regions (FIG. 8) provide psychrometrically controlled air36from outlet32with temperature and humidity ranges controlled more tightly compared to the range of humidity and temperature of air36entering enclosure22from source34, similar to conventional, complicated air systems requiring feedback control involving variable operation of multiple components and constant monitoring of many parameters. Importantly, the air system of the present invention only requires monitoring of a single parameter in order to operate properly; the dry bulb temperature of the psychrometrically controlled air36. That is, it is only required that the dry bulb temperature of the psychrometrically controlled air36be periodically measured from a location between air source34exterior of enclosure22and upstream of energy exchange device60, e.g., compartment56, for the air system to operate properly, even when the air system further comprises energy exchange device80positioned in or along enclosure22for exchanging energy between the psychrometrically controlled air36and refrigerant loop70. It is to be understood that refrigerant loop components, including compressor20, energy exchange devices54,68,46,68,80, reversing valve92, check valves106, expansion devices104previously discussed also operate as previously discussed without requiring more than the dry bulb temperature of the psychrometrically controlled air36.

In one embodiment, a second, independently operated air system may be used in combination with the air system of the present invention, if desired.

Referring now toFIGS. 4-6collectively, compressor20and associated fitting pairs96,97are now discussed. As shown schematically inFIG. 4, compressor20compresses a refrigerant vapor and delivers the vapor from a port84through a tube86that is threadedly engaged with a fitting88at an end of tube86opposite port84. A tube90extends between a reversing valve92at one end of tube90to a fitting94that is threadedly engaged at an opposite end of tube90. The ends of facing or corresponding fittings88,94when threadedly engaged form fitting pair96. An opposite portion of a suction side of refrigerant loop70includes vapor refrigerant flowing from vessel118through tube120that is threadedly engaged with a fitting94at an end of tube120opposite vessel118. A tube122extends between an optional filter124at one end of tube122to a fitting88that is threadedly engaged at an opposite end of tube122. The ends of facing or corresponding fittings88,94when threadedly engaged form a fitting pair97. The vapor refrigerant then flows from filter124through a tube126, returning the vapor refrigerant to a port130of compressor20to complete the refrigerant loop70.

In one embodiment, port84may be directly threadedly connected to fitting88. In one embodiment, port130may be directly threadedly connected to fitting88.

The fittings88,94, such as Series 5505 fittings manufactured by Parker Hannifin headquartered in Cleveland, Ohio, of respective fitting pairs96,97are adapted to be repeatably, e.g., at least twice, threadedly connected and disconnected to/from each other. When fittings88,94are threadedly connected, the resulting fitting pairs96,97form a fluid tight seal to prevent refrigerant flow therethrough, i.e., preventing leakage of refrigerant from between the fittings88,94. Additionally, when fittings88,94are threadedly disconnected from one another, each disconnected side of fittings88,94fitting forming a fluid tight seal preventing refrigerant flow therethrough. Stated another way, the disconnected fittings are self-sealing. In other words, during service, fitting pairs96,97may be opened without loss of refrigerant, allowing compressor20to be removed without evacuating refrigerant and un-brazing refrigeration tubing. Compressor20may be pre-charged with refrigerant using service ports128, which service ports128, in one embodiment, may be re-sealed after charging the compressor.

As a result of fitting pairs96,97, compressor20can be replaced inside of a sealed refrigerant loop70without the requirement of an open flame or other high temp (>600° F.) heating process, such as solder or braze, in addition to not requiring refrigerant recovery and evacuation.

The compressor is arguably, the largest and most complex device to have a possibility of failure in a refrigeration system. A typical compressor replacement requires several (common to all refrigeration circuits) processes to occur by international, national, local and some safety policies. Currently, these processes minimally include the following steps currently if a compressor has failed.

First, the refrigerant from the refrigeration circuit must be recovered using specialty tools that must be approved by the Environmental Protection Agency (EPA), and EPA licensed technicians must also follow strict EPA rules while recovering the refrigerant. This process requires a minimum of a recovery cylinder, a refrigeration gauge set, a recovery machine, and the associated additional hoses or lines or tubes typically required to tie all of these components and the refrigeration circuit in need of repair together.

Second, the compressor must be removed from the circuit. Once the refrigerant is recovered and there is no additional refrigerant inside the system, the compressor can be removed. Some compressors may have what is commonly referred to as “roto-lock” fittings. A roto lock fitting may be mounted directly on a compressor and allows for removal of the compressor without a brazing torch. However, the components described as “roto-locks” are not self-sealing, and once the compressor is removed, the entire refrigeration system is subject to refrigerant leakage to the atmosphere.

If there are no “roto-locks” available on the compressor, the compressor must be removed via an open flame torch, at minimal using a gas such as methylacetylene-propadiene propane (MAPP) gas and usually with an oxyacetylene torch kit. In order to braze safely and to follow EPA and typically unit manufacturers suggestions, nitrogen must be blown through the system where brazing is occurring to remove oxygen from the brazing area preventing oxidation during the heating process. The act of “sweating”/brazing a compressor out of a unit requires at minimal a torch kit of various types, nitrogen bottle or other inert gas that prevents oxidation. Normally many local codes and building ownership safety guidelines exist, that also require the following, a fire extinguisher placed within 6 feet of the technician, as well as a second person known as the “fire watch”. The “fire watch” is dedicated additional personnel whose sole task is to oversee from a reasonable distance and at minimum in the same room and in sight as the technician performing the brazing, to look for any flames that may be catching flammable media of any type on fire. Depending on codes or most building safety guidelines, the “fire watch” must actually be holding a fire extinguisher. This provides improved response time and ability to divert a fire hazard if a fire is in its earliest stages.

Once the compressor is removed the same brazing and nitrogen procedure is used to install the new compressor.

Once the new compressor is installed the technician typically performs a leak test, which per EPA guidelines, requires a pressure of nitrogen or other inert gas to be pressurized to manufacturer specifications in the system for 20 minutes to 30 minutes and review if the pressure has dropped since time of pressurization.

The technician must use another EPA approved device referred to as a vacuum pump. The system must be evacuated for a recommended minimum of a half-hour and must achieve a vacuum of 500 microns or below vacuum. This is measured by a (generally observed as required) tool referred to as a micron gauge.

Once the unit has achieved and held the sufficient vacuum, the system can be recharged with refrigerant. The technician must use a refrigerant scale, and a bottle of the specified equipment's refrigerant to achieve the desired charge.

The pre-charged compressor of the present invention in the field only requires loosening or threadedly disconnecting fittings88,94from fitting pairs96,97in order to disconnect the failed compressor20from the system.

The new compressor20can then be placed in location tied into the system by threadedly connecting fittings88,94to form fitting pairs96,97. No recovery machine, no nitrogen, no brazing, no pressure test, no evacuation, and no charging are required. There is virtually no refrigerant release.

A conventional compressor replacement process is commonly quoted at 6-8 labor hours. However, a replacement of the compressor of the present invention requires about 20 minutes, with none of the specialized equipment discussed above.

In one embodiment, any one or all of energy exchange devices54,68,80, expansion device(s)104, vessels110,118, filter124may be threadedly connected to refrigerant loop70by fittings88,94of fitting pairs96,97.