Abstract:
A fluid compression circuit may include a compression mechanism, a volume, a heat exchanger, a fluid conduit, a thermoelectric device, and a heat-transfer device. The compression mechanism includes first and second members cooperating to form a fluid pocket. The volume receives discharge fluid from the fluid pocket. The heat exchanger is in communication with the volume. The fluid conduit is connected to at least one of the volume and the heat exchanger. The thermoelectric device may include a first side in heat-transfer relation with a member at least partially defining the volume and a second side in heat-transfer relation with ambient air and cooperating with the first side to define a temperature gradient generating electrical current in the thermoelectric device. The heat-transfer device may receive electrical current generated by the thermoelectric device and may be in heat-transfer relation with at least one of the heat exchanger and the fluid conduit.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 11/342,983 filed on Jan. 30, 2006, which is a continuation of U.S. patent application Ser. No. 11/270,879 filed on Nov. 9, 2005. The disclosures of the above applications are incorporated herein by reference. 
    
    
     FIELD 
     The present teachings relate to vapor compression circuits, and more particularly to a vapor compression circuit associated with a thermoelectric device. 
     BACKGROUND 
     Refrigeration systems incorporating a vapor-compression cycle may be utilized to condition the environment of open or closed compartments or spaces. The vapor-compression cycle utilizes a compressor to compress a phase-changing working fluid (e.g., a refrigerant), which is then condensed, expanded and evaporated. Compressing the working fluid generates heat, which, in cooling applications, is waste heat that is discharged to ambient from the compressor and condenser. Because the waste heat is not used or recovered, the lost energy of the waste heat represents an inefficiency of most refrigeration systems. 
     In heating applications, such as in a heat pump system, heat stored in the compressed working fluid is extracted through the condenser to heat a space or compartment. Because efficiency of the heat pump system decreases with ambient temperature, heating may be supplemented at low ambient temperatures by a radiant electrical heat source. Radiant electrical heat sources, however, are typically inefficient and, thus, lower the overall efficiency of the heating application. 
     In some cooling applications, an air flow may be chilled to a very low temperature to reduce the humidity. The low temperature required to remove humidity, however, may be too low for the conditioned space or compartment within a space or compartment to be. In these cases, the dehumidified chilled air may be reheated by electric radiant heat or hot-gas bypass heat to an appropriate temperature while maintaining the low humidity level. Use of radiant electrical heat and a hot gas bypass heat to reheat over-chilled air represents inefficiencies in this type of cooling application. 
     SUMMARY 
     A vapor-compression cycle or circuit may be used to meet the temperature or load demands for conditioning one or more spaces or compartments. Waste heat generated by components of the vapor-compression circuit may be used to generate an electric current that may power other components of the vapor-compression circuit. A thermoelectric device may be placed in heat-transferring relation with the generated waste heat and produce the electrical current, which may be used to generate an electric current to power another device or another thermoelectric device. The other devices may include sensors, switches, controllers, fans, valves, actuators, pumps, compressors, etc. The other thermoelectric device may provide cooling or heating of a fluid in heat-transferring relation therewith to supplement the vapor-compression circuit and facilitate the conditioning of the space or compartment. The utilization of the generated waste heat as an energy source for powering other components or loads may improve the efficiency of the system. 
     In one form, the present disclosure provides a fluid compression circuit that may include a compression mechanism, a volume, a first heat exchanger, a first fluid conduit, a first thermoelectric device, and a heat-transfer device. The compression mechanism may include first and second members cooperating to form a fluid pocket. The volume may receive discharge fluid from the fluid pocket. The first heat exchanger may be in fluid communication with the volume. The first fluid conduit may be fluidly connected to at least one of the volume and the first heat exchanger. The first thermoelectric device may include a first side and a second side. The first side may be in heat-transfer relation with a member at least partially defining the volume. The second side may be in heat-transfer relation with ambient air and may cooperate with the first side to define a temperature gradient generating electrical current in the first thermoelectric device. The heat-transfer device may receive electrical current generated by the first thermoelectric device and may be in heat-transfer relation with at least one of the first heat exchanger and the fluid conduit. 
     In another form, the present disclosure provides a method that may include compressing a working fluid in a compressor from a suction pressure to a discharge pressure. Electrical current may be generated from a heat differential between an ambient environment and a portion of the compressor in heat-transfer relation with the working fluid at the discharge pressure. A heat-transfer device may be powered with the electrical current to cool a component of a fluid compression circuit. 
     In yet another form, the present disclosure provides a compressor that may include a shell, a compression mechanism, a discharge chamber, a volume, and a first thermoelectric device. The compression mechanism may be disposed within the shell. The discharge chamber may be disposed within the shell and may be in fluid communication with the compression mechanism. The volume may be in fluid communication with the discharge chamber. The first thermoelectric device may include a first side in heat-transfer relation with at least one of the discharge chamber and the volume and a second side in heat-transfer relation with ambient air. 
     Further areas of applicability of the present teachings will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the teachings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present teachings will become more fully understood from the detailed description and the accompanying drawings, wherein: 
         FIGS. 1-3  are schematic diagrams of the use of thermoelectric devices according to the present teachings; 
         FIG. 4  is a schematic diagram of a thermoelectric device according to the present teachings; 
         FIG. 5  is a schematic diagram of a compressor with thermoelectric devices according to the present teachings; 
         FIG. 6  is a schematic diagram of a top portion of another compressor with a thermoelectric device according to the present teachings; 
         FIG. 7  is a schematic diagram of a bank of compressors and a thermoelectric device according to the present teachings; 
         FIG. 8  is a schematic diagram of a refrigeration system according to the present teachings; 
         FIG. 9  is a schematic diagram of a refrigeration system according to the present teachings; 
         FIG. 10  is a schematic diagram of a refrigeration system according to the present teachings; 
         FIGS. 11-13  are schematic diagrams of heat pump systems according to the present teachings; and 
         FIG. 14  is a schematic diagram of a refrigeration system according to the present teachings. 
     
    
    
     DETAILED DESCRIPTION 
     The following description is merely exemplary in nature and is in no way intended to limit the teachings, their application, or uses. In describing the various teachings herein, reference indicia are used. Like reference indicia are used for like elements. For example, if an element is identified as  10  in one of the teachings, a like element in subsequent teachings may be identified as  110 ,  210 , etc., or as  10 ′,  10 ″,  10 ′″, etc. As used herein, the term “heat-transferring relation” refers to a relationship that allows heat to be transferred from one medium to another medium and includes convection, conduction and radiant heat transfer. 
     Thermoelectric elements or devices are solid-state devices that convert electrical energy into a temperature gradient, known as the “Peltier effect,” or convert thermal energy from a temperature gradient into electrical energy, known as the “Seebeck effect.” With no moving parts, thermoelectric devices are rugged, reliable and quiet. 
     In use, power is applied from a battery or other DC source to the thermoelectric device, which will have a relatively lower temperature on one side, a relatively higher temperature on the other side, and a temperature gradient therebetween. The lower and higher relative temperature sides are referred herein as a “cold side” and “hot side,” respectively. Further, the terms “cold side” and “hot side” may refer to specific sides, surfaces or areas of the thermoelectric devices. 
     In one application, the hot and cold sides of the thermoelectric device may be placed in heat-transferring relation with two mediums. When power is applied to the thermoelectric device, the resulting temperature gradient will promote heat flow between the two mediums through the thermoelectric device. In another application, one side of the thermoelectric device may be placed in heat-transferring relation with a relatively higher temperature medium providing a heat source and the other side placed in heat-transferring relation with a relatively lower temperature medium providing a heat sink, whereby the resulting hot and cold sides generate electric current. As used herein, the term “heat transfer medium” may be a solid, a liquid or a gas through which heat may be transferred to/from. Thermoelectric devices can be acquired from various suppliers. For example, Kryotherm USA of Carson City, Nev. is a source for thermoelectric devices. 
     One or more thermoelectric devices may generate electric current from waste heat generated in a vapor-compression circuit using the “Seebeck effect.” The electric current generated may be used to power other electrical devices or other thermoelectric devices, which may generate a temperature gradient using the “Peltier effect” to transfer heat therethrough. A power supply may be used to supply a current flow to a thermoelectric device to provide a desired temperature gradient thereacross through the “Peltier effect” and transfer heat therethrough to a desired medium. 
     In  FIG. 1 , a first thermoelectric device  20   a  uses waste or excess heat Q waste  to generate an electric current I that is used to form a temperature gradient across a second thermoelectric device  20   b  to produce recovered heat Q recovered . Hot side  22   a  of thermoelectric device  20   a  is in heat-transferring relation to a source of waste heat Q waste . Cold side  24   a  of thermoelectric device  20   a  is in heat-transferring relation to a heat sink that Q waste  can be expelled thereto. 
     The temperature gradient formed across first thermoelectric device  20   a  generates an electric current I that is supplied to a second thermoelectric device  20   b . The electric current flowing therethrough generates a temperature gradient across second thermoelectric device  20   b  resulting in a hot side  22   b  and a cold side  24   b . The temperature gradient causes a recovered heat Q recovered  to flow through thermoelectric device  20   b . Hot side  22   b  of second thermoelectric device  20   b  is in heat-transferring relation with a medium into which recovered heat Q recovered  is conducted, while cold side  24   b  of second thermoelectric device  20   b  is in heat-transferring relation to a heat source. Thus, in  FIG. 1  a first thermoelectric device  20   a  is exposed to waste heat Q waste  to cause a second thermoelectric device  20   b  to generate recovered heat Q recovered . 
     The electric current generated by a thermoelectric device  20  may also be used to activate or drive an electrical device or meet an electrical load (hereinafter referred to as load  26  and/or “L”) as shown in  FIG. 2 . Again, waste heat Q waste  is utilized to generate a temperature differential between hot and cold sides  22 ,  24  and generate electric current I. Thus, in  FIG. 2 , thermoelectric device  20  is placed in heat-transferring relation to a source of waste heat Q waste  and a heat sink to generate electric current I that is used to power load  26 . Load  26  is utilized generically herein to refer to any type of device requiring an electric current. Such devices, by way of non-limiting example, include compressors, pumps, fans, valves, solenoids, actuators, sensors, controllers and other components of a refrigeration system. The sensors may include, such as by way of non-limiting example, pressure sensors, temperature sensors, flow sensors, accelerometers, RPM sensors, position sensors, resistance sensors, and the like and may be represented by “S” in the drawings. The various valves, solenoids and actuators may be represented by “V” in the drawings. 
     Referring now to  FIG. 3 , a power supply  28  is connected to a thermoelectric device  20  to generate a desired heat Q desired . Power supply  28  may supply a current flow I to thermoelectric device  20  to cause a temperature gradient to be formed between hot and cold sides  22 ,  24 . The temperature gradient generates a desired heat Q desired . Hot side  22  may be placed in heat-transferring relation with a medium into which heat Q desired  is conducted. Power supply  28  may modulate current flow I to maintain a desired temperature gradient and produce a desired heat Q desired . Thus, in  FIG. 3 , a power supply  28  provides an electric current I within thermoelectric device  20 , which generates a source of desired heat Q desired . 
     Thermal enhancing devices or thermal conductors  30 ,  32  may be placed in heat-transferring relation with sides  22 ,  24  of one or more thermoelectric devices  20  to enhance or facilitate heat transfer through the thermoelectric device  20  and a medium, as shown in  FIG. 4 . A thermoelectric device  20  having one or more thermal conductors  30 ,  32  is referred to herein as a thermoelectric module (TEM)  33 , which may include multiple thermoelectric devices  20 . Thermal conductors  30 ,  32  may be referred to herein as hot and cold thermal conductors  30 ,  32 , respectively. It should be appreciated, that the terms “hot” and “cold” are relative terms and serve to indicate that that particular thermal conductor is in heat-transferring relation with the respective hot or cold side of a thermoelectric device  20 . 
     Heat transfer may be enhanced by increasing the heat-conductive surface area that is in contact with the medium into which the heat is to be conducted. For example, micro-channel tubing may accomplish the enhancing of the heat flow. The fluid medium flows through the micro channels therein and the hot or cold side of the thermoelectric device is placed in heat-transferring contact with the exterior surface of the tubing. When the medium is a gas, such as air, the thermal conductor may be in the form of fins which may accomplish the enhancement of the heat transfer to/from the medium. 
     To enhance heat transfer, the thermal conductor may be shaped to match a contour of a heat source. For example, when it is desired to place a thermoelectric device in heat-transferring relation with a curved surface, the thermal conductor may have one surface curved so that it is complementary to the surface of the solid through which the heat is to be conducted while the other side of the thermal conductor is complementary to the hot or cold side of the thermoelectric device  20 . 
     Enhanced heat transfer may be accomplished through heat-conducting materials, layers or coatings on the thermoelectric device  20 . Thermal conductors  30 ,  32  may include materials, layers or coatings having a high thermal conductivity whereby heat transfer through the thermoelectric device  20  is conducted efficiently. By way of non-limiting example, materials having a high thermal conductivity include aluminum, copper and steel. Moreover, heat-conducting adhesives may also be used as thermal conductors  30 ,  32 . Regardless of the form, the thermal conductors  30 ,  32  have a high thermal conductivity. 
     In a vapor-compression cycle or circuit, a compressor  34  compresses a relatively cool working fluid (e.g., refrigerant) in gaseous form to a relatively high temperature, high-pressure gas. The compressing process generates waste heat Q waste  that is conducted through the compressor to ambient. Waste heat Q waste  may be utilized by a thermoelectric device  20  to power another thermoelectric device  20 , and/or a load  26 . 
     Referring to  FIG. 5 , a schematic view of portions of an exemplary compressor, in this case an orbital scroll compressor  34  by way of a non-limiting example, generally includes a cylindrical hermetic shell  37  having welded at the upper end thereof a cap  38  and at the lower end thereof a base  58 . A refrigerant discharge passage  39 , which may have a discharge valve (not shown) therein, is attached to cap  38 . Other major elements affixed to shell  37  include a transversely extending partition  40  that is welded about its periphery at the same point that cap  38  is welded to shell  37 , upper and lower bearing assemblies (not shown) and a motor stator  41  press-fitted therein. A driveshaft or crankshaft  42  is rotatably journalled in the upper and lower bearing assemblies. The lower portion of shell  37  forms a sump  43  that is filled with lubricating oil which gets internally distributed throughout compressor  34  during operation. 
     Crankshaft  42  is rotatably driven by an electric motor including stator  41 , with windings passing therethrough, and a rotor  44  press-fitted on crankshaft  42 . Upper and lower surfaces of rotor  44  have respective upper and lower counterweights  45 ,  46  thereon. An Oldham coupling (not shown) couples crankshaft  42  to an orbiting scroll member  47  having a spiral vane or wrap  48  on the upper surface thereof. A nonorbiting scroll member  49  is also provided having a wrap  50  positioned in meshing engagement with wrap  48  of orbiting scroll member  47 . Nonorbiting scroll member  49  has a center-disposed discharge passage  51  that is in fluid communication with a discharge muffler chamber  52  defined by cap  38  and partition  40 . An inlet port  53  on shell  37  allows refrigerant to flow into a suction side or inlet chamber  54 . 
     Compressor  34  also includes numerous sensors, diagnostic modules, printed circuit board assemblies, solenoids, such as internal and external capacity modulation solenoids, switches, such as a switch to change resistance of motor  36  to provide a first resistant for start-up and a second resistance for continuous operation, and other electrically-actuated devices or loads  26 . These electrical devices may be internal or external to the compressor and may be stationary or rotating with the rotating components of the compressor. 
     During operation, motor  36  causes rotor  44  to rotate relative to stator  41 , which causes crankshaft  42  to rotate. Rotation of crankshaft  42  causes orbiting scroll member  47  to orbit relative to nonorbiting scroll member  49 . Working fluid within suction chamber  54  is pulled into the space between wraps  48 ,  50  and progresses toward the central portion due to the relative movement therebetween. 
     Pressurized working fluid is discharged from scroll members  47 ,  49  through discharge passage  51  and flows into discharge chamber  52 . The working fluid within discharge chamber  52  is at a relatively high temperature and pressure. Compressed high-temperature, high-pressure working fluid flows from discharge chamber  52  through discharge passage  39  and onto the other components of the vapor-compression circuit within which compressor  34  is employed. 
     During operation, waste heat Q waste  is generated throughout compressor  34 . This waste heat Q waste  may be conducted to a thermoelectric device  20 . Waste heat Q waste  may be generated by rotor  44 , which gets hot when rotated and is cooled by the internally distributed lubricant and the working fluid (suction gas) within suction chamber  54 . The heat flow from rotor  44  to the lubricant and/or suction side working fluid represents a source of waste heat Q waste  that may be conducted to a thermoelectric device  20 . 
     As shown in  FIG. 5 , a TEM  33   a , which may be attached to rotor  44 , includes a thermoelectric device  20   a  with hot side  22   a . Hot side  22   a  is in heat-transferring relation to rotor  44  while cold side  24   a  is in heat-transferring relation with the lubricant and working fluid within suction chamber  54 . The temperature differential between the hot and cold sides  22   a ,  24   a  causes a heat Q a  to flow through TEM  33   a , which generates an electric current that is supplied to a load  26   a . Attached to moving rotor  44 , TEM  33   a  powers load  26   a  that is also rotating with rotor  44  or shaft  42 . For example, load  26   a  may include a resistance switch that changes the resistance of the rotor so that a higher resistance is realized for a startup and a lower resistance is realized during nominal operation, a temperature sensor, an RPM sensor, and the like. While TEM  33   a  is shown as being attached to the upper portion of rotor  44 , it should be appreciated that TEM  33   a  can be attached to other portions of rotor  44 , such as a middle, lower or internal portion, made integral with upper or lower counterweight  45 ,  46 , or in direct contact with lubricant within sump  43 . 
     Partition  40 , which separates the relatively hot discharge gas within discharge chamber  52  from the relatively cooler suction gas within suction chamber  54 , conducts waste heat Q waste , which may be used to generate electrical power within a thermoelectric device  20 . By attaching a TEM  33   b  to partition  40  with hot thermal conductor  30   b  in heat-transferring relation with partition  40  and cold thermal conductor  32   b  in heat-transferring relation with the suction gas within suction chamber  54 , waste heat Q b  may be transferred from partition  40  through TEM  33   b  and into the suction gas within suction chamber  54 . Waste heat Q b  generates an electric current in thermoelectric device  20   b  of TEM  33   b . TEM  33   b  may be connected to an internal electric load  26   b   1  or an external electric load  26   b   2 . TEM  33   b  may be attached in a fixed manner to a stationary component, such as partition  40 , which facilitates the attachment to stationary loads either internal or external to compressor  34 . By positioning thermoelectric device  20  in heat-transferring relation with a stationary component conducting waste heat Q waste , an electric current to power a load  26  either internal or external to compressor  34  may be generated. 
     Waste heat Q waste  from the relatively hot discharge gas within discharge chamber  52  is conducted through cap  38  to the ambient environment within which compressor  34  is located. A TEM  33   c  may be attached to cap  38  with a hot thermal conductor  30   c  in heat-transferring relation with the exterior surface of cap  38  and the cold thermal conductor  32   c  in heat-transferring relation with the ambient environment. As shown in  FIG. 5 , cold thermal conductor  32   c  includes fins over which the ambient air flows and hot thermal conductor  30   c  includes a contoured surface matched to the exterior contour of cap  38 . Hot thermal conductor  30   c  has a greater surface area in contact with cap  38  than in contact with hot side  22   c  of thermoelectric device  20   c . The temperature differential between the ambient air and cap  38  causes waste heat Q c  to flow through TEM  33   c  and generate an electric current that powers load  26   c , which may be external ( 26   c   1 ) or internal ( 26   c   2 ) to compressor  34 . Thermoelectric device  20  may be placed in heat-transferring relation to the relatively hot discharge gas in discharge chamber  52  (via cap  38 ) and the relatively cold ambient environment to provide a temperature gradient that may be used to generate electric current to power a load. 
     Because of the temperature differential between discharge gas within discharge passage  39  and the ambient environment, a TEM  33   d  attached to discharge passage  39  with the hot thermal conductor  30   d  in heat-transferring relation to discharge passage  39  and the cold thermal conductor  32   d  in heat-transferring relation to the ambient environment causes heat Q d  to flow through TEM  33   d . The thermoelectric device  20   d  of TEM  33   d  generates electric current that may be used to power load  26   d . Thus, a thermoelectric device  20  may be disposed in heat-transferring relation to the relatively hot gas within the discharge passage and the ambient environment to generate an electric current that can be used to power a load. 
     During the compressing of the refrigerant between wraps  48 ,  50  of orbiting and non-orbiting scroll members  47 ,  49 , the temperature and pressure of the working fluid increases as it approach central discharge passage  51 . As a result, the temperature differential between the relatively cool suction gas on one side of orbiting scroll member  47  and the relatively hot discharge gas near discharge passage  51  generates waste heat Q e . A TEM  33   e  may be attached to orbiting-scroll member  47  adjacent or opposite to discharge passage  51 . Specifically, hot thermal conductor  30   e  of TEM  33   e  is placed in heat-transferring relation to a bottom surface of orbiting scroll member  47  generally opposite discharge passage  51 . Cold thermal conductor  32   e  of TEM  33   e  is disposed in heat-transferring relation to the suction gas and lubricant flowing within suction chamber  54 . As waste heat Q e  flows through TEM  33   e , the thermoelectric device  20   e  of TEM  33   e  generates electric current that may be used to power load  26   e . Thus, a thermoelectric device  20  may be disposed in heat-transferring relation to the discharge gas and suction gas adjacent the orbiting scroll member to generate electric current that can be used to power a load. 
     During operation, stator  41  generates waste heat Q f  that is transferred to the internally distributed lubricant and/or suction gas in the suction chamber  54 . A TEM  33   f  may be attached to stator  41  with the hot thermal conductor  30   f  in heat-transferring relation to stator  41  and cold thermal conductor  32   f  is in heat-transferring relation to the lubricant and/or suction gas in suction chamber  54 . The temperature differential between stator  41  and the lubricant and/or suction gas within suction chamber  54  causes waste heat Q f  to flow through TEM  33   f , wherein thermoelectric device  20   f  generates electric current that may be used to power load  26   f . While TEM  33   f  is shown as being attached to the upper portion of stator  41 , it should be appreciated that TEM  33   f  can be attached to other portions of stator  41 , such as a middle, lower or internal portion, or in direct contact with lubricant within sump  43 . Thus, a thermoelectric device may be disposed in heat-transferring relation to the stator and the lubricant or suction gas to generate electric current that can be used to power a load. 
     The lubricant within sump  43  of compressor  34  is relatively hot (relative to the ambient environment) and heat waste Q g  is conducted from the lubricant through shell  37  to the ambient environment. A TEM  33   g  may be positioned with cold thermal conductor  32   g  in heat-transferring relation to the ambient environment and hot thermal conductor  30   g  in heat-transferring relation to the lubricant within sump  43 . This may be accomplished by integrating TEM  33   g  within the wall of shell  37 . The temperature differential between the lubricant and ambient causes waste heat Q g  to flow through thermoelectric device  20   g  in TEM  33   g  and generate electric current that may be used to power load  26   g . Thus, a thermoelectric device  20  disposed in heat-transferring relation to the relatively hot lubricant and relatively cool ambient environment may be used to generate electric current to power a load. 
     Referring to  FIG. 6 , a partial schematic view of a top portion of another exemplary compressor, in this case an orbital scroll compressor  34 ′ having a direct discharge by way of non-limiting example is shown. Compressor  34 ′ is similar to compressor  34  discussed above with reference to  FIG. 5 . In compressor  34 ′, however, discharge passage  39 ′ communicates directly with discharge passage  51 ′ of non-orbiting scroll member  49 ′ such that the compressed working fluid (discharge gas) flows directly into discharge passage  39 ′ from discharge passage  51 ′. A muffler  56 ′ is attached to discharge passage  39 ′. The relatively hot compressed working fluid flows through muffler  56 ′. Waste heat Q waste  from the relatively hot discharge gas within muffler  56 ′ is conducted through the walls of muffler  56 ′ to the ambient environment within which compressor  34 ′ is located. A TEM  33 ′ may be attached to muffler  56 ′ with hot thermal conductor  30 ′ in heat-transferring relation with the exterior surface of muffler  56 ′ and cold thermal conductor  32 ′ in heat-transferring relation with the ambient environment. Cold thermal conductor  32 ′ may include fins over which the ambient air flows and hot thermal conductor  30 ′ may include a contoured surface matched to the exterior contour of muffler  56 ′ to facilitate heat transfer. The temperature differential between the ambient air and muffler  56 ′ causes waste heat Q to flow through TEM  33 ′ and generate an electric current that powers load  26 ′. Thus, thermoelectric device  20 ′ may be placed in heat-transferring relation to the relatively hot discharge gas in muffler  56 ′ (via the exterior surface of muffler  56 ′) and the relatively cold ambient environment to provide a temperature gradient that may be used to generate electric current to power a load. 
     Referring to  FIG. 7 , a multi-compressor system  60  including compressors  34   1 - 34   n  are arranged in parallel with the relatively hot, high-pressure discharge gas from each compressor  34  flowing into a common discharge manifold  61  is shown. The temperature differential between the discharge gas and ambient causes waste heat Q to flow from the discharge gas to the ambient environment through manifold  61 . Positioning a TEM  33  adjacent discharge manifold  61  with a hot thermal conductor  30  in heat-transferring relation to discharge manifold  61  and cold thermal conductor  32  in heat-transferring relation to the ambient air about discharge manifold  61  may generate electric current from waste heat Q flowing through thermoelectric device  20  within TEM  33 . The electric current may be used to power load  26 . Thus, in a multi-compressor system having a common discharge manifold, a thermoelectric device may be positioned between the relatively hot discharge gas in the manifold and the ambient environment to generate an electric current from the waste heat Q to power a load  26 . 
     Referring to  FIG. 8 , an exemplary refrigeration system  64  includes a compressor  65 , a condenser  66 , an expansion device  67  and an evaporator  68  all connected together to thereby form a vapor-compression circuit  69 . Condenser  66  transfers a heat Q 3  from the relatively hot working fluid flowing therethrough to an airflow flowing there across and condenses the working fluid. Evaporator  68  is operable to extract a heat flow Q 4  from an airflow flowing there across and transfer it to the relatively cool and expanded working fluid flowing therethrough. 
     Refrigeration system  64  includes various loads  26  that require electricity to operate. Loads  26  may include electrically driven fans  70 ,  71  which push air across condenser  66  and evaporator  68 , respectively, various valves, solenoids or actuators  72  and various sensors  73 . Additionally, load  26  may include a controller  74 , which may be used to control or communicate with valves  72 , sensors  73 , compressor  65 , fans  70 ,  71  and other components of refrigeration system  64 . The various power requirements of refrigeration system  64  may be met by a power distribution member  75  which supplies current to power the various loads  26  of refrigeration system  64 . 
     The power demands of the various loads  26  may be provided by a power supply  76 , which may provide both AC current and DC current, through power-distribution block  75 . The electric current may be supplied by individual connections directly to power supply  76 , through one or more power distribution devices, and/or through controller  74 . 
     Waste heat Q waste  generated by refrigeration system  64  may be conducted to one or more thermoelectric devices  20  to generated electric current supplied to load  26 . As shown in  FIG. 8 , a TEM  33   a  may capture waste heat Q 1  from compressor  65  and generate current I supplied to power-distribution block  75 . Additionally, TEM  33   b  may extract waste heat Q 2  from the relatively high-temperature working fluid flowing through vapor-compression circuit  69 , particularly compressed working fluid that has not been condensed, and generate current I supplied to power-distribution block  75 . 
     During startup of refrigeration system  64 , a TEM  33  will not produce power to supply load  26 . Rather, during startup, power may be supplied by power supply  76 . Once refrigeration system  64  reaches steady state (nominal) operation, waste heat Q waste  will be generated and TEM  33  may produce electric current. 
     As the electric current production by one or more TEM  33  increases, the use of power supply  76  may be reduced. Power demands of load  26  may be partially or fully met by the electric current generated by one or more TEM  33 , which may also supply current to power one or more low-power-consuming components while power supply  76  supplies current to meet the power demand of high-power-consuming components, such as compressor  65 . 
     An energy-storage device  78  may provide temporary startup power to one or more components of refrigeration system  64 . Energy-storage devices, such as rechargeable batteries, ultra capacitors, and the like, may store a sufficient quantity of power to meet the requirements, particularly at system startup, of some or all of the components of refrigeration system  64  up until the time TEM  33  is able to produce sufficient current to power those components. Excess current generated by TEM  33  may be utilized to recharge energy-storage device  78  for a subsequent startup operation. Thus, energy storage device  78  may be part of load  26 . 
     In refrigeration system  64 , thermoelectric devices  20  may use waste heat Q waste  to generate electric current that can power various components of refrigeration system  64 . The electric current supplied by thermoelectric devices may be used to supplement electric current from power supply  76  and/or meet the demand of the refrigeration system. Additionally, an energy-storage device  78  may provide the initial startup power requirements of refrigeration system  64  until one or more thermoelectric devices  20  are able to replace the electrical power supplied by energy-storage device  78 . 
     Referring now to  FIG. 9 , a refrigeration system  164  includes a vapor-compression circuit  169  and TEM  133 . TEM  133 , which produces an electric current I to power a load  126 , may extract heat Q 102  from the relatively high-temperature, non-condensed working fluid flowing through vapor-compression circuit  169  between compressor  165  and condenser  166 , thereby de-superheating the working fluid flowing into condenser  166 . 
     Working fluid may exit compressor  165  at, by way of non-limiting example, 182° F. and arrive at TEM  133  at about 170° F. If the ambient environment is at say 95° F., a 75° F. temperature differential across TEM  133  produces waste heat Q 102  to flow from the working fluid to the ambient through TEM  133 , which reduces the temperature of the working fluid prior to flowing into condenser  166 . Because the heat Q 103  required to be extracted by condenser  166  to meet the needs of evaporator  168  is reduced, compressor  165  may operate more efficiently or at a lower capacity or at a lower temperature, such as by way of non-limiting example 115° F. Thermoelectric device  20  may power load  126  while de-superheating non-condensed working fluid thereby meeting part of all of the power demand and increasing the efficiency of the system. De-superheating the working fluid enables condenser  166  to operate more efficiently or be sized smaller than what would be required if no de-superheating were to occur, further helping thermoelectric device meet system power requirements. 
     Referring to  FIG. 10 , a refrigeration system  264  includes a pair of thermoelectric modules  233   a ,  233   b  for subcooling the condensed working fluid exiting condenser  266 . First thermoelectric module  233   a  extracts waste heat Q 201  from compressor  265  and generates an electric current I that is supplied to second thermoelectric module  233   b , which is in heat-transferring relation to vapor-compression circuit  269 . The current supplied by first TEM  233   a  drives the temperature gradient across second TEM  233   b  to allow the removal of heat Q 205  from condensed working fluid in vapor-compression circuit  269 . Cold side  224   b  of thermoelectric device  220   b  is in heat-transferring relation to the condensed working fluid within vapor-compression circuit  269  exiting condenser  266 , where heat Q 205  is extracted from the condensed working fluid and transferred to the ambient. To enhance the removal of heat Q 205  from the condensed working fluid to the ambient environment, the flow of air caused by fan  270  may be directed over hot thermal conductor  230   b  of second TEM  233   b.    
     Second TEM  233   b  may remove heat Q 205  to sub-cool the condensed working fluid therein and increase the cooling capacity of refrigeration system  264 . Condenser  266  may reduce the working fluid temperature to approximately ambient temperature and second thermoelectric module  233   b  may further cool the condensed working fluid to below-ambient temperature by extracting heat Q 205  therefrom. The lower-temperature condensed working fluid provides a larger cooling capacity for evaporator  268 , which can extract a larger quantity of heat Q 204  from the air flowing across evaporator  268 , thus achieving a greater cooling capacity. 
     Referring to  FIG. 11 , a refrigeration system  364  operated as a heat pump is shown. In this system, a thermoelectric module  333  is utilized to supplement the heating capacity of refrigeration system  364 . Hot thermal conductor  330  of TEM  333  is in heat-transferring relation with a portion of the relatively high-temperature, high-pressure working fluid exiting compressor  365  and flowing through an auxiliary flow path  380 . Cold thermal conductor  332  of TEM  333  is in heat-transferring relation with the condensed working fluid exiting condenser  366 . Power supply  376  selectively supplies electric current to TEM  333  thereby forming a temperature gradient across TEM  333  which extracts heat Q 306  from the condensed working fluid and transfers the heat Q 306  to the portion of the relatively high-temperature, high-pressure working fluid flowing through auxiliary flow path  380 , further increasing the temperature of the working fluid. 
     This higher-temperature working fluid is directed through an auxiliary condenser  382  to supplement the heat transfer to the air flowing over condenser  366 . The air flow generated by fan  370  flows over condenser  366  then auxiliary condenser  382 . Auxiliary condenser  382  transfers heat Q 312  from the higher-temperature working fluid flowing therethrough to the air flowing thereacross, thereby increasing the temperature of the air flow and providing additional heat transfer to the air flow. 
     The condensed working fluid exiting auxiliary condenser  382  joins with the condensed working fluid exiting condenser  366  prior to flowing past TEM  333 . The condensed working fluid flows through expansion device  367  and evaporator  368  wherein heat Q 304  is extracted from the air flowing thereacross. Accordingly, a thermoelectric device in refrigeration system  364  transfers heat to a portion of the relatively high-temperature, high-pressure working fluid exiting the compressor which is subsequently transferred to an air flow flowing across an auxiliary condenser, thereby supplementing the overall heat transferred to the air flow. The electric current supplied to the thermoelectric device is modulated to provide varying levels of supplementation of the heat Q 312  transferred to the air flowing over the condenser and the auxiliary condenser. 
     Referring to  FIG. 12 , a refrigeration system  464  operated as a heat pump is shown. In refrigeration system  464 , a thermoelectric module  433  selectively transfers heat to a single-phase fluid flowing through a single-phase, heat-transfer circuit  486  which supplements the heating capacity of refrigeration system  464 . Heat-transfer circuit  486  includes a pump  487  and a heat exchanger  483  arranged adjacent condenser  466  such that air flow generated by fan  470  flows across both condenser  466  and heat exchanger  483 . 
     Cold thermal conductor  432  is in heat-transferring relation with the condensed working fluid exiting condenser  466  which extracts heat Q 406  therefrom. Hot thermal conductor  430  is in heat-transferring relation with the single-phase fluid flowing through heat-transfer circuit  486  and transfers heat Q 406  thereto. Power supply  476  modulates the current flowing to thermoelectric device  420  within TEM  433  to generate and maintain a desired temperature gradient thereacross, thereby resulting in a desired quantity of heat Q 406  transferred to the single-phase fluid and increasing the temperature of the single-phase fluid to a desired temperature. Pump  487  pumps the single-phase fluid through heat exchanger  483  which transfers heat Q 412  from the single-phase fluid to the air flowing thereacross, which raises the temperature of the air flow. A variety of single-phase fluids can be utilized within heat-transfer circuit  486 . By way of non-limiting example, the single-phase fluid may be a potassium formate or other types of secondary heat transfer fluids, such as those available from Environmental Process Systems Limited of Cambridgeshire, UK and sold under the Tyfo® brand, and the like. In refrigeration system  464 , a thermoelectric device transfers heat Q 406  from the condensed working fluid exiting the condenser to a single-phase fluid flowing through a heat-transfer circuit which transfers heat Q 412  to the air flowing across heat exchanger  483 . 
     Referring to  FIG. 13 , a refrigeration system  564  operated as a heat pump is shown. Refrigeration system  564  is similar to refrigeration system  464  with the addition of a second single-phase, heat-transfer circuit  588 . Second heat-transfer circuit  588  includes a pump  589  and a subcooler  590 . Subcooler  590  is in heat-transferring relation with condensed working fluid exiting condenser  566  and the single-phase fluid flowing through heat-transfer circuit  588 . Subcooler  590  transfers heat Q 507  from the condensed working fluid flowing therethrough to the single-phase fluid flowing therethrough, which increases the temperature of the single-phase fluid. 
     Cold thermal conductor  532  of TEM  533  is in heat-transferring relation with the single-phase fluid flowing through heat-transfer circuit  588 . Hot thermal conductor  530  of TEM  533  is in heat-transferring relation with the single-phase fluid flowing through heat-transfer circuit  586 . Power supply  576  modulates the current flowing to thermoelectric device  520  to maintain a desired temperature differential thereacross which transfers heat Q 508  from the single-phase fluid within heat-transfer circuit  588  to the single-phase fluid in heat-transfer circuit  586  through thermoelectric device  520 . Heat Q 508  increases the temperature of the single-phase fluid flowing through heat-transfer circuit  586 . Heat Q 512  is transferred from the single-phase fluid flowing through heat-transfer circuit  586  to the air flowing across heat exchanger  583 , thereby increasing the temperature of the air flow. Refrigeration system  564  uses two single-phase fluid heat-transfer circuits  586 ,  588  in heat-transferring relation to one another through thermoelectric device  520  to supplement the heating of the air flow flowing across condenser  566 . 
     Referring to  FIG. 14 , a refrigeration system  664  providing a dehumidification and reheating of the cooling air provided thereby is shown. Refrigeration system  664  includes vapor-compression circuit  669  having a working fluid flowing therethrough. Evaporator  668  is operated at a very low temperature and extracts heat Q 604  from the air flow flowing thereacross which lowers the humidity and temperature of the air flow. First and second heat-transfer circuits  691 ,  692  in heat-transferring relation through TEM  633  transfer heat to the air flow to raise the temperature thereby making the air flow suitable for its intended application. 
     First heat-transfer circuit  691  includes a pump  693  and a subcooler  694  and has a single-phase fluid flowing therethrough. Subcooler  694  transfers heat Q 609  from the condensed working fluid exiting condenser  666  to the single-phase fluid flowing through first heat-transfer circuit  691  which increases the temperature of the single-phase fluid. Cold thermal conductor  632  is in heat-transferring relation with the single-phase fluid flowing through first heat-transfer circuit  691  while hot thermal conductor  630  is in heat-transferring relation with the single-phase fluid flowing through second heat transfer circuit  692 . Power supply  676  modulates the current flowing to thermoelectric device  620  in TEM  633  to maintain a desired temperature gradient thereacross and transfer heat Q 610  from the single-phase fluid flowing through first heat-transfer circuit  691  to the single-phase fluid flowing through second heat-transfer circuit  692  through thermoelectric device  620 . 
     Heat Q 610  increases the temperature of the single-phase fluid flowing through second heat-transfer circuit  692 . A pump  695  pumps the single-phase fluid in second heat-transfer circuit  692  through a reheat coil  696 . The air flow induced by fan  671  flows across both evaporator  668  and reheat coil  696 . Reheat coil  696  transfers heat Q 611  from the single-phase fluid flowing therethrough to the air flow flowing thereacross. Heat Q 611  increases the temperature of the air flow without increasing the humidity. Refrigeration system  664  utilizes two single-phase heat transfer circuits  691 ,  692  in heat-transferring relation therebetween with a thermoelectric device to reheat an air flow dehumidified and chilled by the evaporator of the vapor compression circuit. 
     While the present teachings have been described with reference to the drawings and examples, changes may be made without deviating from the spirit and scope of the present teachings. It should be appreciated that the orbiting scroll compressors shown in  FIGS. 5 and 6  are by way of a non-limiting example and may not show all of the components therein. Orbital scroll compressors are shown and described in greater detail in U.S. Pat. No. 6,264,446 entitled “Horizontal Scroll Compressor”; U.S. Pat. No. 6,439,867 entitled “Scroll Compressor Having a Clearance for the Oldham Coupling”; U.S. Pat. No. 6,655,172 entitled “Scroll Compressor with Vapor Injection”; U.S. Pat. No. 6,679,683 entitled “Dual Volume-Ratio Scroll Machine” and U.S. Pat. No. 6,821,092 entitled “Capacity Modulated Scroll Compressor”, all assigned to the assignee of the present invention and incorporated by reference herein. Other types of compressors generate waste heat that can be utilized with one or more thermoelectric devices to generate a current flow that can be used elsewhere. For example, the compressors can be either internally or externally-driven compressors and may include rotary compressors, screw compressors, centrifugal compressors, and the like. Moreover, while TEM  33   g  is shown as being integrated in the wall of shell  37 , it should be appreciated that TEMs may be integrated into other components, if desired, to be in direct contact with a heat source or heat sink. Furthermore, while the condensers and evaporators are described as being coil units, it should be appreciated that other types of evaporators and condensers may be employed. Additionally, while the present teachings have been described with reference to specific temperatures, it should be appreciated that these temperatures are provided as non-limiting examples of the capabilities of the refrigeration systems. Accordingly, the temperatures of the various components within the various refrigeration systems may vary from those shown. 
     Furthermore, it should be appreciated that additional valves, sensors, control devices and the like can be employed, as desired, in the refrigeration systems shown. Moreover, thermal insulation may be utilized to promote a directional heat transfer so that desired hot and cold sides for the thermoelectric device are realized. Accordingly, the description is merely exemplary in nature and variations are not to be regarded as a departure from the spirit and scope of the teachings.