Abstract:
In one embodiment, an operating condition of a thermoelectric module is monitored. It is determined when the monitored operating condition exceeds a desired range. Upon determining the monitored operating condition exceeds the desired range, a thermal adjustment is applied to the thermal condition to direct the operating condition to within the desired range. The monitoring the operating condition may include measuring an operating temperature of an environment adjacent a surface of the thermoelectric module, a surface temperature of a portion of the thermoelectric module, a thermal differential between the first surface and the second surface of the thermoelectric module, and an output voltage of the thermoelectric module. The desired range includes a temperature range below a level at which the thermoelectric module will sustain thermal damage and a thermal differential capable of causing the thermoelectric module to generate a minimum desired output voltage.

Description:
FIELD OF THE INVENTION 
     The present disclosure relates to electrical power systems, and more specifically, to generating electrical power using thermoelectric modules. 
     BACKGROUND OF TEE INVENTION 
     The “thermoelectric effect” is the conversion of a thermal differential between opposing surfaces of a thermoelectric material to electric voltage, and vice versa. The thermoelectric effect, forms of which are known as the “Peltier effect” or the “Seebeck effect,” for one example, is the technology used in small electrical refrigeration systems used in portable beverage coolers and cars. Applying a voltage across a thermoelectric module causes a current to be driven through the semiconducting material of the thermoelectric module. The flow of current through the thermoelectric module causes the thermoelectric module to draw heat from a cooling side of the thermoelectric module to an opposing surface of the module. The cooling side is coupled with an enclosure that serves as a solid-state cooling device. 
     Conversely, the thermoelectric effect also can be used to generate electric voltage by disposing thermoelectric modules where one surface will be exposed to a relatively hot temperature, while an opposing surface will be exposed to a relatively cold temperature; instead of the voltage causing the thermal differential, the thermal differential is used to generate electric voltage. 
       FIG. 1  depicts a thermoelectric module  100  used to generate electric voltage. The thermoelectric module  100  is situated between a hot thermal source  110  and a cold thermal source  120 , creating a thermal differential ΔH  130  between a first surface  140  of the thermoelectric module  100  presented to the hot thermal source  110  and a second surface  150  of the thermoelectric module  100  presented to the cold thermal source  120 . As a result of the thermal differential  130 , the thermoelectric module  100  generates a voltage differential ΔV  160 . 
     Using thermoelectric modules to generate electrical power involves a number of concerns. First, the greater the thermal differential between the surfaces of the thermoelectric modules, the greater will be the voltage produced as a result of the thermoelectric effect. It is desirable, therefore, to dispose one side of the thermoelectric module to a much hotter or much colder environment than the opposing surface. If the thermal differential is too small, the thermoelectric modules will not generate enough voltage. Second, changes in the thermal differential affect the voltage generated. Thus, if the differential is less than anticipated, the thermoelectric module may not generate enough voltage. Alternatively, if the differential becomes greater than anticipated or desired, the thermoelectric module may produce too much voltage, and the excess voltage may damage devices that receive voltage from the thermoelectric module. Third, currently available thermoelectric modules are relatively fragile. Thus, in attempting to expose one surface of a thermoelectric module to a very hot environment in order to create a very high thermal differential, the high heat may damage the thermoelectric module. 
     There is growing interest in using thermoelectric modules to generate power. After all, countless engines, motors, furnaces, lights, electrical circuits, and other devices generate waste heat as a byproduct of their operation. Moreover, energy must be expended to cool these engines and other devices to keep them functioning or protect them from being damaged. Similarly, natural sources of heat, such as geothermal sources generate heat that represents a wasted opportunity for the generation of power. If this wasted or excess heat could be harnessed with thermoelectric modules, electrical energy could be generated from otherwise unused heat sources. Unfortunately, problems in maintaining sufficient thermal differentials, preventing excessive thermal differentials, or simply being unable to regulate thermal differentials undermines the practicality and effectiveness of using thermoelectric modules to generate electrical power. 
     SUMMARY OF THE INVENTION 
     Embodiments of the present invention are directed to applying a thermal adjustment to a thermoelectric module to preserve the operating conditions of a thermoelectric module within a desirable range. Embodiments of the present invention may advantageously protect thermoelectric modules from high temperatures or maintain the thermoelectric modules within a desired thermal differential. 
     In one embodiment, an operating condition of a thermoelectric module is monitored. It is determined when the monitored operating condition exceeds a desired range. Upon determining the monitored operating condition exceeds the desired range, a thermal adjustment is applied to the thermal condition to direct the operating condition to within the desired range. The monitoring of the operating condition may include measuring an operating temperature of an environment adjacent a surface of the thermoelectric module, a surface temperature of a portion of the thermoelectric module, a thermal differential between the first surface and the second surface of the thermoelectric module, or an output voltage of the thermoelectric module. The desired range includes a temperature range below a level at which the thermoelectric module will sustain thermal damage or a thermal differential capable of causing the thermoelectric module to generate a minimum desired output voltage. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the present invention are described in detail below with reference to the following drawings. 
         FIG. 1  (Background) is block diagram of a thermoelectric module generating an output voltage as a result of being disposed to a thermal differential. 
         FIG. 2  is a block diagram of a thermoelectric module equipped with a controllable heat sink according to an embodiment of the present invention. 
         FIGS. 3A-3B  and  4 A- 4 B are block diagrams of a thermoelectric module submitted to a thermal differential and a thermal adjustment to adjust a voltage differential generated by the thermoelectric module. 
         FIGS. 5A-5B  are isometric views of heat sinks suitable for applying a thermal adjustment to a thermoelectric module in an air-based or other gas-based cooling system. 
         FIG. 6A  is a block diagram of an air-based or gas-based cooling system for applying a thermal adjustment to one surface of one or more thermoelectric modules. 
         FIG. 6B  is a block diagram of a cooling system for applying a thermal adjustment to both opposing surfaces of a thermoelectric module. 
         FIG. 7  is a block diagram of a heat sink suitable for applying a thermal adjustment to a thermoelectric module using a liquid-based cooling system. 
         FIG. 8  is a block diagram of a liquid-based cooling system for applying a thermal adjustment to one or more thermoelectric modules. 
         FIG. 9  is a flow diagram of a process of applying a thermal adjustment to a thermoelectric module to maintain a desired level of operation of the thermoelectric module. 
         FIG. 10  is a flow diagram of a process of using a thermoelectric module to generate power while applying thermal adjustments to maintain the desired level of operation of the thermoelectric module. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the present invention are related to regulating a temperature of a thermoelectric module presented to a heat source. By regulating the temperature of the thermoelectric module or the thermal differential across the thermoelectric module, the output voltage of the thermoelectric module can be regulated, and the thermoelectric module can be protected from damage. 
       FIG. 2  is a general, schematic view of a thermoelectric module  200  with which an embodiment of the invention is used. A first surface  210  of the thermoelectric module  200  is presented to an input heat source  220 . The input heat source  220 , in one mode, is a source of waste heat, such as an engine coolant line or an engine exhaust. The input heat source  220  may include a “hot” heat sink that conveys heat from a principal heat source. For example, if the principal heat source is an engine, the input heat source  220  may include a heat sink that conveys heat from an exhaust line or cooling line running from the engine block. Embodiments of the invention may include a controllable heat sink or heat source allowing the heat conveyed to the heat sink to be regulated, for example, to prevent thermal damage to the thermoelectric module  200 . 
     A second surface  230  of the thermoelectric module  200  is presented to a controllable heat sink  240 . A difference between a temperature H  250  of the input heat source  220  and a temperature C  260  of the controllable heat sink  240  results in a thermal differential ΔH  270 . The thermal differential ΔH  270  applied across the thermoelectric module  200  results in a voltage differential ΔV  280 . The voltage differential ΔV  280  is proportional to the thermal differential ΔH  270 . 
     In a context where the input heat source  220  is a waste heat source, such as an engine coolant line or engine exhaust, the temperature H  250  typically will vary. As previously described, the variation of the temperature H  250  may present problems if the temperature H  250  is either too low or too high. 
     To account for these variations, the controllable heat sink  240  allows for the temperature C  260  to be varied to change the thermal differential ΔH  270 . Thus, if the temperature H  250  is too low relative to the temperature C  260 , the controllable heat sink  240  can be cooled to reduce the temperature C  260  and increase the thermal differential ΔH  270 . On the other hand, if the temperature H  250  is too high, the temperature of the controllable heat sink H  220  can be cooled to protect the thermoelectric module  200  from damage. Alternatively, if the thermal differential ΔH  270  is generating too high of a voltage differential ΔV  280 , the temperature C  260  of the controllable heat sink can be increased to reduce the thermal differential ΔH  270  and, in turn, reduce the voltage differential ΔV  280 . In one embodiment, the input heat source  220  could be controllably coupled with the controllable heat sink  240  to reduce the thermal differential across the thermoelectric module  200 . Correspondingly, when the input heat source  220  includes a heat sink conveying heat from a principal heat source, the heat conveyed from the principal heat source may also be regulated to control the heat applied to the thermoelectric module  200 , as well as to regulate the thermal differential ΔH  270  applied across the thermoelectric module  200 . 
       FIG. 3A  illustrates an exemplary case when the temperature H  300  presented by the heat source  220  is lower than desired. As in the case of the exemplary embodiments illustrated in this and other figures, the input heat source  220  may include a controlled or uncontrolled heat source. Because the temperature H  300  is lower than desired, the thermal differential ΔH  310  between the temperature H  300  and the temperature C  320  across the thermoelectric module  200  yields a resulting voltage differential ΔV  330  lower than desired. 
       FIG. 3B  illustrates how, using one embodiment, the temperature C  350  of the controllable heat sink  240  is reduced, causing an increased thermal differential ΔH  360  with no change in the temperature H  300  of the heat source  220 . The increased thermal differential ΔH  360  yields an increased voltage differential ΔV  370  across the thermoelectric module  200 . 
     On the other hand,  FIG. 4A  illustrates an exemplary case in which the temperature H  400  presented by the heat source  220  is higher than desired. The thermal differential ΔH  410  between the temperature H  400  and the temperature C  420  across the thermoelectric module  200  becomes higher than intended or desired, resulting in a voltage differential ΔV  430  that also is higher than is desired or intended. It should be noted that a change in the voltage differential is not necessarily a linear response as a result of a change in a thermal differential. Accordingly, thermal adjustments applied to adjust for changes in the temperature H  400  should consider the voltage differential-to-thermal differential response of the thermoelectric module. 
       FIG. 4B  illustrates how the temperature C  450  of the controllable heat sink  240  is increased, causing a reduced thermal differential ΔH  460  with no change in the temperature H  400  of the heat source  220 . The reduced thermal differential ΔH  460  yields a reduced voltage differential ΔV  470  across the thermoelectric module  200 . Alternatively, if the heat source  220  includes an input heat sink conveying heat from a principal heat source, the heat conveyed from the principal heat source to the heat sink can be regulated, as described further below. Thus, regulating the heat conveyed to the input heat source  220  can reduce the heat applied to the thermoelectric module to protect the thermoelectric module from damage, or adjust the thermal differential ΔH  460  to cause a reduced voltage differential ΔV  370  across the thermoelectric module  200 . 
     As illustrated in the examples of  FIGS. 3A-3B  and  4 A- 4 B, the temperature of the controllable heat sink  240  can be adjusted to change the thermal differential across the thermoelectric module  200  to account for variations in the heat supplied by the heat source  220 . The thermal differential thus can be changed to change the resulting voltage differential. Alternatively, the temperature applied by the controllable heat sink  240  can be adjusted to reduce the temperature or the thermal differential to which the thermoelectric module  200  is subjected to reduce damage to the thermoelectric module. Further alternatively, the heat conveyed from the principal heat source to the heat sink can be regulated to reduce the temperature or the thermal differential to which the thermoelectric module  200  is subjected to reduce damage to the thermoelectric module. 
     The controllable heat sink may be manifested in a number of forms, and the temperature of the controllable heat sink may be controlled using a variety of systems. The cooling system may include a fluid cooled system, in which the fluid may be in a gaseous or a liquid form. Also, as is described further below, it may be desirable to employ a control system to direct the operations of the cooling system. The control system can monitor the operating conditions of the thermoelectric module, and as a result of those conditions, adjust the cooling applied to the controllable heat sink to adjust or maintain the thermal differential across the thermoelectric module. 
     A first exemplary cooling system uses air cooling, or cooling with another gas, as illustrated in  FIGS. 5A and 5B  and  FIG. 6A .  FIGS. 5A and 5B  illustrate heat sinks that are suitable for an air-cooled or other gas-cooled system.  FIG. 5A  shows a heat sink  500  that includes a planar block  510  that supports a plurality of cooling fins  520 . Both the planar block  510  and the cooling fins  520  are composed of a thermally-conductive material, such as copper, or an aluminum alloy. The planar block  510  is disposed on the component to be cooled. The planar block  510  conveys heat generated by the component to the fins  520 . The fins  520 , which present an increased surface area for the disbursal of heat, radiate the heat to the environment surrounding the fins  520 . 
       FIG. 5B  shows a heat sink  550  that includes a planar block  560  that supports one or more heat pipes  570  that disburse heat from the planar block. The heat pipe  570  may include a plurality of fins  580  at an end removed from the planar block  560  to further facilitate temperature transfer. In one embodiment, the heat pipe  570  is a hollow, enclosed tube in which a coolant, such as water, ethanol, or mercury is enclosed. When the heat pipe  570  operates in alignment with gravity, gravity draws the coolant to an end adjacent the planar block  560 . Heat emanating from the planar block  560  causes the coolant to evaporate where it is cooled at the opposite end, where the coolant condenses and falls back toward the end disposed at the planar block  560 . Where the heat pipe  570  will operate in a context where it is not aligned with gravity, an internal wicking structure is employed to draw the condensed coolant toward a surface disposed at the planar block. The heat sinks  500  and  550  are two exemplary forms of heat sinks; other types of heat sinks also are suitable for an embodiment of a controllable heat sink using air-cooling or gas-cooling. Embodiments of the invention may also employ vapor chamber heat sinks or any other desired form of heat sinks for applying thermal adjustments to the thermoelectric module. Embodiments of the invention are not limited to the use of any particular selected form of heat sink. 
       FIGS. 6A and 6B  illustrate exemplary embodiments of systems for applying thermal adjustments to thermoelectric modules to protect the modules from damage, control the voltage output of the modules, or to address other operating concerns. The systems of  FIGS. 6A and 6B  both include, but do not show, original heat sources used to develop the thermal differential that supports the thermoelectric effect exploited by the thermoelectric modules. Many original heat sources may be used. For example, in a vehicle such as an automobile, an aircraft, a watercraft, or any other type of vehicle, the engine that motivates the vehicle will generate heat both as a result of cooling the engine and in the engine&#39;s exhaust. Either or both of these heat sources may be exploited to supply heat to facilitate a thermoelectric effect. Similarly, machinery or other industrial systems, including engines, motors, furnaces, or any other type of machinery, generate heat that can be used to facilitate a thermoelectric effect. Further still, naturally occurring phenomena, such as radiant heat from the Earth or the Sun, or geothermal heat in liquid or steam form can be used to facilitate a thermoelectric effect. Any of these heat sources, or any other heat source, can be tapped to facilitate a thermoelectric effect. 
     Notwithstanding, for visual clarity, these original heat sources are not included in  FIGS. 6A  or  6 B, as they were not included in  FIGS. 4A-4B  and  5 A- 5 B. As described, the input heat sinks or heat sources shown convey heat from the original heat source to facilitate the thermoelectric effect. In some embodiments, the heat conveyed is controlled to apply thermal adjustments to the thermoelectric modules, or the heat conveyed is controlled as part of applying thermal adjustments to the thermoelectric modules. 
       FIG. 6A  illustrates a cooling system  600  suitable for transferring heat from a thermoelectric module  602  equipped with a controllable heat sink  604 . The controllable heat sink  604  is disposed in a gaseous cooling loop  606 . Upon passing over the heat sink  604 , gas is heated to an elevated temperature C↑  608 . The gas at the elevated temperature C↑  608  is circulated by convection, a fan, or other motivating force (not shown) until it is exposed to a cooling gas source  612 . The cooling gas source  612  cools the gas to a reduced temperature C↓  610 , where it circulates via the cooling loop  606  to draw heat from the heat sink  604 . 
     In one mode, the cooling system  600  includes a control unit  614  that is coupled with a sensor  616  that monitors operating conditions of the thermoelectric module  602 . The control unit may include a thermostat or another type of control logic operable to direct a cooling mechanism  618  to control the degree of cooling applied within the cooling loop  606  based on the operating conditions. For example, the sensor  616  may monitor the operating temperature of the thermoelectric module  602 , including the environmental temperature attending the thermoelectric module  602 , or the surface temperature of the thermoelectric module  602 . Alternatively, because the voltage differential generated by the thermoelectric module  602  is proportional to the thermal differential to which the thermoelectric module  602  is subjected, the sensor  616  may monitor the voltage generated by the thermoelectric module  602  as indicative of the thermal differential to which the thermoelectric module  602  is exposed. 
     The cooling mechanism  618  may include a controlled port, a fan, or another mechanism the control unit  614  directs in response to the operating conditions read from the sensor  616 . In a system such as automobile, where the heat source  620  includes a cooling line or an exhaust line from the engine, or a heat sink conveying heat from the cooling line or an exhaust line, the cooling mechanism  618  may include a fan mechanically engaged to an engine to take advantage of the operation of the engine to motivate a flow from the cooling gas source  612  to the cooling cycle. The fan may include a clutch mechanism to selectively increase the air flow based on signals from the control unit  614 . The clutch mechanism could be selectively engaged and geared by the control unit in order to control the thermal adjustment applied by the fan. Thus, if the sensor  616  indicates that more cooling is needed, the control unit  614  engages the cooling mechanism  618  to increase the contact of the cooling gas source  612  with the cooling cycle  606 . Conversely, if less cooling is needed, the control unit  614  can engage the cooling mechanism  618  to reduce the exposure of the cooling cycle  606 . Alternatively, in a system such as a jet aircraft, where the heat source  620  includes hot jet exhaust, the cooling mechanism  618  may include a panel that exposes the cooling cycle  606  to ambient air as a cooling gas source  612 . Because jet engines operate at high altitudes where the ambient air is quite cold and inherently flows by at very high speeds, controlling the area of the cooling loop  606  exposed to the cooling gas source  612  may be affected by selectively opening or closing a panel to the outside air. 
     The control unit  614  also is coupled with a control  622  operable to control the heat supplied to the input heat sink or heat source  620  from an original heat source (not shown). Thus, whether the original heat source is from an engine, a natural source, or another source, the control unit can reduce the heat applied to the thermoelectric module and change the thermal differential applied to the input heat sink or heat source. The control  622  may include a valve or similar control that can be used to reduce the heat conveyed to the input heat sink or heat source  620 . 
       FIG. 6B  illustrates another cooling system  650  suitable for controlling the thermal differential applied to a thermoelectric module  652  by controlling the heat applied to each of the surfaces of the thermoelectric module. As in the system  600  ( FIG. 6A ), the cooling system  650  transfers heat from a thermoelectric module  652  equipped with a secondary heat sink  654 . The secondary heat sink  654  is disposed in a secondary cooling loop  656 , which may include a gaseous or a liquid cooling loop. Upon passing over the secondary heat sink  654 , cooling fluid, either gaseous or liquid, is heated to an elevated temperature C↑  658 . The fluid at the elevated temperature C↑  658  is circulated by convection, a fan, or other motivating force (not shown) until it is exposed to a cooling source  662 . The cooling source  662  cools the fluid to a reduced temperature C↓  660 , where it circulates via the secondary cooling loop  656  to draw heat from the secondary heat sink  654 . 
     The cooling system  650  includes a control unit  664  that is coupled with a secondary sensor  668  that monitors operating conditions of the thermoelectric module  652 . The control unit  664  may include a thermostat or another type of control logic operable to direct a cooling mechanism  670  to control the degree of cooling applied within the secondary cooling loop  656  based on the operating conditions. For example, the secondary sensor  668  may monitor the operating temperature of the thermoelectric module  652 , including the environmental temperature attending the thermoelectric module  652 , or the surface temperature of the thermoelectric module  652 . Alternatively, because the voltage differential generated by the thermoelectric module  652  is proportional to the thermal differential to which the thermoelectric module thermoelectric module  652  as indicative of the thermal differential to which the thermoelectric module  652  is exposed. 
     The cooling mechanism  670  may include a controlled port, a fan, or another mechanism the control unit  664  directs in response to the operating conditions read from the sensor  668 . In a system such as automobile, where the heat source includes a primary heat sink  680  that conveys heat from a principal heat source, such as a cooling line or an exhaust line from the engine, the cooling mechanism  670  may include a fan mechanically engaged to an engine to take advantage of the operation of the engine to motivate a flow from the cooling source  662  to the cooling cycle. The fan may include a clutch mechanism to selectively increase the air flow based on signals from the control unit  664  as previously described with regard to  FIG. 6A . Thus, if the sensor  668  indicates that more cooling is needed, the control unit  664  engages the cooling mechanism  670  to increase the contact of the cooling gas source  662  with the cooling cycle  656 . Conversely, if less cooling is needed, the control unit  664  can engage the cooling mechanism  670  to reduce the exposure of the cooling cycle  656 . 
     Additionally, because heat is applied to the thermoelectric module  652  by a primary heat sink  680  conveying heat from a principal heat source, the operating conditions to which the thermal module  652  is subjected can be regulated by adjusting the heat conveyed to the primary heat sink  680 . The heat conveyed by the primary heat sink  680  can be regulated in a number of different ways. For example, if the heat is conveyed to the primary heat sink  680  by a fluid, the flow of fluid can be restricted so that the primary heat sink  680  receives less heat. The heat conveyed may be regulated by the control unit  664 , or another control unit. The control unit  664  suitably is coupled with a primary sensor  692  that measures the temperature of the primary heat sink  680 , the surface temperature of the thermoelectric module  652 , or the attendant temperature about the thermoelectric module  652 . The control unit  664 , thus, may restrict the fluid flow that conveys heat to the primary heat sink  680  when the temperature or thermal differential to which the thermoelectric module  652  is subjected becomes too high. 
     Alternatively, as illustrated in  FIG. 6B , the primary heat sink  680  may convey heat from the original heat source (not shown), and the primary heat sink  680  is cooled by another primary cooling loop  682 . The control unit  664  coupled with the primary sensor  692  monitors operating conditions of the thermoelectric module  652  and controls a cooling mechanism  690  to regulate the cooling of the primary heat sink  680 . The cooling mechanism  690  may include a controlled port, a fan, or another mechanism the control unit  664  directs in response to the operating conditions read from the primary sensor  692 . Thus, if the primary sensor  692  indicates that more cooling is needed, the control unit  664  engages the cooling mechanism  690  to increase the contact of the cooling source  668 , which may be the same cooling source used in the secondary cooling loop  656  or a different cooling source. Conversely, if less cooling is needed, the control unit  664  can engage the cooling mechanism  690  to reduce the exposure of the primary cooling cycle  682 . 
     Upon passing over the primary heat sink  680 , cooling fluid, either gaseous or liquid, is heated to an elevated temperature C↑  684 . The fluid at the elevated temperature C↑  684  is circulated by convection, a fan, or other motivating force (not shown) until it is exposed to a cooling source  688 . The cooling source  688  cools the fluid to a reduced temperature C↓  686 , where it circulates via the primary cooling loop  682  to draw heat from the primary heat sink  680 . 
       FIGS. 7-8  illustrate a controllable heat sink and a cooling system in which liquid cooling is used to cool a thermoelectric module.  FIG. 7  illustrates a liquid cooled heat sink  700 . The heat sink  700  includes a planar block  710  that is disposed against the component to be cooled, such as a thermoelectric module. The planar block  710  comprises a thermally conductive material to transfer heat from the thermoelectric module to loops of a cooling tube  720 . The cooling tube  720  receives cooled liquid that absorbs heat from the planar block  710  and carries the heated liquid through a cooling loop as described in connection with  FIG. 8 . This type of heat sink is commonly termed a cold plate heat exchanger. 
       FIG. 8  illustrates a liquid cooling system  800  suitable for transferring heat from a thermoelectric module  810  equipped with a heat sink  820 . The controllable heat sink  820  may include a cold plate heat exchanger as described in connection with  FIG. 7  that is included in a liquid cooling loop  830 . Upon passing through the heat sink  820 , liquid is heated to an elevated temperature C↑  842 . The liquid at the elevated temperature C↑  842  is circulated by a pump  870  that circulates the liquid coolant around the cooling loop  830  between the controllable heat sink  820  and a radiator  844 . The liquid coolant circulates through the radiator  844 , which also may be in the nature of the heat sink  700  of  FIG. 7 . As the liquid coolant passes through the radiator  844 , it transfers heat to a cooling source  846 . In a system such as an automobile or an aircraft, the cooling source  846  may be the ambient air to which the radiator  844  is exposed. Alternatively, the cooling source  846  may include a body of water, such as a river, lake, or ocean, when the thermoelectric module  810  is included in a watercraft or another system that operates adjacent to the body of water, or a hot spring or other liquid geothermal source. The cooling source  846  cools the liquid coolant to a reduced temperature C↓  848 , where it returns via the cooling loop  830  to draw heat from the heat sink  820 . 
     In one mode, the cooling system  800  includes a control unit  850  that is coupled with a sensor  860  that monitors the operating conditions of the thermoelectric module  810 . The control unit  850  may include a thermostat or another type of control logic operable to direct a cooling mechanism, such as the pump  870 , to control the degree of cooling applied within the cooling loop  830  based on the operating conditions. For example, the sensor  860  may monitor the operating temperature of the thermoelectric module  810 , including the environmental temperature attending the thermoelectric module  810 , or the surface temperature of the thermoelectric module  810 . Alternatively, because the voltage differential generated by the thermoelectric module  810  is proportional to the thermal differential to which the thermoelectric module  810  is subjected, the sensor  860  may monitor the voltage  880  generated by the thermoelectric module  810  as indicative of the thermal differential to which the thermoelectric module  810  is exposed. 
     In one embodiment, the pump  870  is an electric pump that is powered, for example, by a portion of the voltage  880  generated by the thermoelectric module  810 . Alternatively, the pump  870  may include a pump that is mechanically coupled to and driven by an engine, where the pump  870  includes a clutched mechanism controlling the degree of cooling transferred from the cooling source  846  to the radiator  844 . The clutch or other switching mechanism used to control the pump may be powered by a portion of the voltage  880  generated by the thermoelectric module  810 . 
     Using the exemplary systems previously described or other temperature adjustment systems,  FIGS. 9 and 10  illustrate modes of adjusting the temperature of a thermoelectric module used to generate power.  FIG. 9  is a generalized mode of applying a temperature adjustment to a thermoelectric module. At  910 , operating conditions of one or more thermoelectric modules are monitored. As previously described, for example, the operating conditions may include an ambient temperature attending a thermoelectric module, or a surface temperature of a thermoelectric module. Alternatively, the operating conditions may include a voltage output of a thermoelectric module, which is representative of the thermal differential to which the thermoelectric module is subjected. 
     At  920 , it is determined if the operating conditions are outside the desirable operating range of the thermoelectric module. For example, if the surface temperature of the thermoelectric module is too high, or the thermal differential to which the thermoelectric module is subjected is too high so as to possibly damage the thermoelectric module or produce excessive voltage, the operating conditions may be determined to transcend a desirable range. If so, at  930 , thermal adjustment is applied to the thermoelectric modules. For example, if thermal adjustment is to be applied to the thermoelectric modules, a cooling mechanism such as a fan, pump, or access panel is motivated to apply a thermal adjustment to bring the thermoelectric modules back to within a desired operating range. Once the thermal adjustment is applied, or if it was found at  920  that the operating conditions are not beyond a desired operating range, at  910 , the operating conditions of the thermoelectric module continue to be monitored. 
       FIG. 10  illustrates a mode of generating electrical power using one or more thermoelectric modules, and applying a thermal adjustment to facilitate the desirable operation of the thermoelectric modules. At  1010 , a first surface of the thermoelectric module or cells is submitted to a heat source that is used to create a thermal difference to enable the thermoelectric effect. At  1020 , the power generated by the thermoelectric module or cells is received by a system that will store or use the power. At  1030 , operating conditions of one or more thermoelectric modules are monitored. 
     At  1040 , it is determined if the operating conditions are outside the desirable operating range of the thermoelectric module. If so, at  1050 , a thermal adjustment is applied to the thermoelectric modules. For example, if a thermal adjustment is to be applied to the thermoelectric modules, a cooling mechanism such as a fan, pump, or access panel is motivated to apply a thermal adjustment to bring the thermoelectric modules back to within a desired operating range. Once the thermal adjustment is applied, or if it was found at  1040  that the operating conditions are not beyond a desired operating range, at  1030 , the operating conditions of the thermoelectric module continue to be monitored. 
     While preferred and alternate embodiments of the invention have been illustrated and described, as noted above, many changes can be made without departing from the spirit and scope of the invention. Accordingly, the scope of the invention is not limited by the disclosure of the preferred embodiment. Instead, the invention should be determined entirely by reference to the claims that follow.