Thermoelectric Management Unit
Embodiments of the invention provide a thermal management unit including a housing, at least one fan, a plurality of thermoelectric modules, at least one heat sink assembly coupled to the plurality of thermoelectric modules, and controller providing power to the plurality of thermoelectric modules. The thermal management unit also includes a printed circuit board incorporating the plurality of thermoelectric modules and electrically connecting the plurality of thermoelectric modules to the controller. The printed circuit board separates an ambient side of the thermal management unit and an enclosure side of the thermal management unit.
This application claims priority under 35 U.S.C. §119 to U.S. Provisional Patent Application Nos. 61/146,593, filed on Jan. 22, 2009 and 61/172,266, filed on Apr. 24, 2009, the entire contents of which are incorporated herein by reference.
BACKGROUNDThermal management units, such as air conditioning and heating units, are used to cool and heat electrical enclosures. Most conventional thermal management units use compressors. However, thermoelectric (TE) devices can convert electrical current into heating or cooling based on the Peltier effect and are generally much more efficient than compressors.
Electrical circuits that provide electrical current to the TE devices are often housed in junction boxes separate from the thermal management units. These junction boxes are bulky and take up an excessive amount of space within the electrical enclosures.
SUMMARYSome embodiments of the invention provide a thermal management unit for an enclosure. The thermal management unit includes a housing, at least one fan to direct air flow through the housing, a plurality of thermoelectric modules, at least one heat sink assembly coupled to the plurality of thermoelectric modules, and controller providing power to the plurality of thermoelectric modules. The thermal management unit also includes a printed circuit board incorporating the plurality of thermoelectric modules and electrically connecting the plurality of thermoelectric modules to the controller. The printed circuit board separates an ambient side of the thermal management unit and an enclosure side of the thermal management unit. The plurality of thermoelectric modules can include a first plurality of thermoelectric modules positioned in an area of higher air flow in the housing and a second plurality of thermoelectric modules position in an area of lower air flow in the housing. The controller can provide higher power to the first plurality of thermoelectric modules and lower power to the second plurality of thermoelectric modules.
Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings.
The following discussion is presented to enable a person skilled in the art to make and use embodiments of the invention. Various modifications to the illustrated embodiments will be readily apparent to those skilled in the art, and the generic principles herein can be applied to other embodiments and applications without departing from embodiments of the invention. Thus, embodiments of the invention are not intended to be limited to embodiments shown, but are to be accorded the widest scope consistent with the principles and features disclosed herein. The following detailed description is to be read with reference to the figures, in which like elements in different figures have like reference numerals. The figures, which are not necessarily to scale, depict selected embodiments and are not intended to limit the scope of embodiments of the invention. Skilled artisans will recognize the examples provided herein have many useful alternatives and fall within the scope of embodiments of the invention.
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In one embodiment as shown in
The TE management unit 10 can include one or more ambient fans 34 coupled to the panel 32 (which are illustrated as fan housings in
The heat sink assemblies 20 can be designed in a modular fashion so that any suitable number of heat sink assemblies 20 can be used to achieve the desired thermal capacity. The modular heat sink assemblies 20 can also minimize the effects of shear forces that occur in the TE modules 26, as compared to conventional, larger heat sink assemblies that are coupled to multiple TE modules. Since the colder side of the TE module 26 will contract in size and the warmer side of the TE module 26 will expand in size, large heat sinks attached to multiple TE modules tend to experience shear stresses, warping, and the loss of physical contact, and thus, the loss of efficient thermal transfer with some of the TE modules. Also, when large heat sinks warp, gaskets between the heat sink and the enclosure can start to leak, allowing water from outdoors to leak inside the enclosure.
Using the modular heat sink assemblies 20 can help minimize the effects of shear stresses and warping at the interface between the TE modules 26 and the heat sinks 22, 24. A phase change material (PCM), or other suitable thermal transfer material, can also be used at the interface between the TE modules 26 and the heat sinks 22, 24. The PCM can enhance thermal transfer. Once suitable PCM is sold by Berquist under the brand Hi-Flow® 225U, as described in the tables of
The housing 14 can be a side-mount type unit and can be rack-mounted to the enclosure 12. In other embodiments, the housing 14 can be mounted to the enclosure 12 via other suitable mounting methods.
In some embodiments, the modular design concept is based on using the single panel 32 that incorporates the TE modules 26. The TE modules 26 can be ganged together in order to provide the TE management unit 10 with increased thermal capacity. More specifically, each TE module 26 configuration can have a wiring scheme that allows the TE management unit 10 to achieve a maximum combination of efficiency and thermal power.
Fan power has a large effect on efficiency of the TE management unit 10, and fan speed has a large affect on fan power. The fans 34, 36, as well as the TE modules 26, can be monitored and controlled to achieve maximum efficiency at all combinations of temperatures. In some embodiments of the invention, the speed of the fans 34, 36 can be varied (e.g., in substantially real-time) based on a combination of inputs to a controller 38 to maximize efficiency given a particular thermal load. The thermal transfer, or thermal load, can be determined by measuring a temperature difference across the TE modules 26. The controller 38 can incorporate this information into a programmed algorithm to set the optimum fan speed for each combination of power input, cooling output, ambient temperature, and enclosure temperature. Fan speed can be controlled using pulse width modulation (PWM) control with a tachometer output to monitor status and, in some embodiments, the ambient fans 34 can be controlled separately from the enclosure fans 36. In addition, power to the TE modules 26 can be controlled to vary the thermal transfer of the TE management unit 10.
In some embodiments, the approach to variable control can be to adjust the TE module power based on the thermal load required. Normal fan control options for this approach can be as follows: (1) let both the enclosure and ambient fans run full speed; (2) let the enclosure fan run full speed and speed control the ambient fans based on external air in temperature or air out temperature; (3) let the external fan run full speed and speed control the ambient fan based on a temperature difference that is set at a fixed value; and (4) speed control both the enclosure and ambient fans, as described in the previous paragraph. The control of the fans 34, 36 and the TE modules 26 according to some embodiments of the invention is further described below with respect to the flowcharts of
As shown in
The first sensor circuit, including sensor S1, can be routed to the microcontroller circuit 56 via a connection 58. The second sensor circuit, including sensor S2, can be routed to the microcontroller circuit 56 via a connection 60. The third sensor circuit, including sensor S3, can be routed to the microcontroller circuit 56 via a connection 62. Finally, the fourth sensor circuit, including sensor S4, can be routed to the microcontroller circuit 56 via a connection 64.
The temperature sensors S1-S4 can be remotely mounted in various airflow regions (e.g., of the housing 14) for temperature control. For example, one of the temperature sensors (S1, for example) can be positioned at the enclosure inlet 11 and another temperature sensor (S2, for example) can be positioned at the enclosure outlet 13. A third temperature sensor (S3, for example) can be positioned at the ambient inlet 15 and a fourth temperature sensor (S4, for example) can be positioned at the ambient outlet 17. Therefore, temperatures can be sensed at both the inlets and outlets of the enclosure air loop and the ambient air loop. In some embodiments, the temperature sensors S1-S4 can have a temperature accuracy of about +/−2 degrees Celsius. In addition, in some embodiments, the controller 38 can have an operational temperature range of about minus 40 degrees Celsius to about 80 degrees Celsius.
As shown in
The fans 34, 36 can be modulated from minimum to maximum control points. For example, the enclosure fans 36 can be operated between 75% and 100% of their maximum speed and the ambient fans 34 can be operated between 25% and 100% of their maximum speed. In one embodiment, the maximum speed for both the enclosure fans 36 and the ambient fans 34 can be about 4900 rotations per minute (RPM). In another embodiment, the enclosure fans 36 can operate at or above about 3000 RPM and the ambient fans 34 can operate at or above about 1000 RPM. In some embodiments, the fans 34, 36 can be digitally stable up to 4 kilo-Hertz control frequency.
As shown in
The multiplexer U1 can be an 8-input multiplexer, such as Part No. 74HC151, manufactured by Philips Semiconductors. Pins 1-4, which can be coupled to connections 82, 84, 86, and 88 can be multiplexer inputs of the multiplexer U1. Pins 12-14 can also be multiplexer inputs and can receive outputs from various override devices, such as smoke detectors, door switches, etc., which the control circuit 39 can monitor. In
The multiplexer U1 also receives an enable input at pin 7 from the microcontroller circuit 56 via a connection 98. In addition, select inputs to pins 9, 10, and 11 of the multiplexer U1 are routed from the microcontroller circuit 56 via connections 100, 102, and 104, respectively. The output of the multiplexer, at pin 5, is routed to the microcontroller circuit 56 via a connection 106. The select inputs (connections 100, 102, and 104 from the microcontroller circuit 56) can also be routed to the alarm circuit 46, as shown in
The latch U4 can also provide output signals to remote devices, such as slave units. For example, pins 9 and 10 can be connected to remote units via connections 124 and 126, through resistors R45 and R46, respectively. Both resistors R45 and R46 can have a resistance of about 330 ohms. The remote units can also be connected to a reference voltage V1 via a connection 128, and ground via a connection 130. The latch U4 can also output signals to alarm light emitting diodes (LEDs) via pins 11 and 12. For example, two LEDS, D1 and D2, can be used to communicate alarm outputs. In one embodiment, D1 is a green LED and D2 is a red LED. If an alarm function is active (i.e., if a fault has occurred), D1 can be switched off and D2 can be switched on. If the alarm function is not active, the D1 can be switched on and D2 can be switched be off. The LEDs D1 and D2 can be connected to pins 11 and 12 through resistors R47 (about 100 ohms) and R48 (about 100 kilo-ohms), respectively.
The latch U4 can be an 8-bit addressable latch, such as part no. 74HC259, manufactured by Philips Semiconductors. Address inputs to pins 1, 2, and 3 can be from the connections 104, 102, and 100, respectively, from the microctroller circuit 40 (the connections 104, 102, and 100 are also routed to the tachometer circuit 44). An enable input to pin 14 of the latch U4 can be received from the microcontroller circuit 56 via a connection 132. Pin 15 can be a conditional reset input, which is active when low, and can be connected to the voltage V1. Pin 13 can receive input data from the microcontroller circuit 56 via a connection 134.
Various faults can activate alarm outputs for the alarms. Faults that can activate the first, second, and third alarms, in some embodiments, are described below.
The first alarm output can be an airflow alarm, caused by failing fans (e.g., a fan fault) or an excessive temperature change across the enclosure or ambient airflow loops (e.g., a temperature delta fault). Ambient or enclosure temperature delta faults can occur when a measured temperature across the TE module 26 is greater than about 15 degrees Celsius. If this occurs, the controller 38 can, in addition to activating the first alarm output, reset the TE power to about zero and ramp the power back up to a steady state value. If there is an enclosure temperature delta fault, the controller 38 can also run the enclosure fans 36 at maximum speed. Similarly, if there is an ambient temperature delta fault, the controller 38 can also run the ambient fans 34 at maximum speed. Additionally, if any fan 34, 36 fails, the controller 38 can run all other functioning fans 34, 36 at maximum speed.
The second alarm output can be a temperature or sensor failure alarm, due to a failing sensor (e.g., a sensor fault) or an exceeded enclosure high or low temperature limit as measured by the enclosure inlet temperature sensor S1 (e.g., a temperature fault). For example, a high temperature alarm can be activated when a temperature sensor (the enclosure inlet temperature sensor S1, for example), is about 10 degrees Celsius above the cooling set-point and a low temperature alarm can be activated when the temperature sensor (also the temperature sensor S1, for example) is about 10 degrees Celsius below the heating set-point. Plus or minus about 10 degrees Celsius can be a factory default for the high and low temperature limits and can be adjusted by a user. A sensor fault can occur, and the second alarm can be activated, if any temperature sensor S1-S4 reads less than about minus 50 degrees Celsius or greater than about 85 degrees Celsius. If either of these conditions is measured, it can be assumed that the temperature sensor in question (i.e., S1, S2, S3, or S4) has failed and, in addition to the second alarm, the controller 38 can set the TE voltage to about 18 volts, direct current (Vdc) and set the fans 34, 36 to maximum speed.
A third alarm output can be a power fault alarm, which can be triggered by power faults (e.g., if the controller input voltage is out of range, the fan voltage or current is out of range, or if the TE module voltage or current is out of range). For example, a power fault can be triggered if the TE current (i.e., the current to the TE modules 26) is greater than about 20 amperes, direct current, or the voltage is greater than about 24 Vdc. If such an event occurs, the controller 38 can reset the TE module power to zero and ramp the power back up to a steady state value, and run the fans 34, 36 at maximum speed. In another example, a power fault can be triggered if the fan current (i.e., the current to the fans 34, 36) is greater than about 4 amperes, direct current. If such an event occurs, the controller 38 can reset the fan power to zero and ramp the voltage back up to about 12 Vdc.
The controller 38 can have a delay period (e.g., thirty seconds or fifteen seconds) for alarm outputs to minimize nuisance alarms. Any of the alarms can be on and stable for the full delay period to activate the output and display functions when the delay period has been exceeded. For any faults, the controller 38 can either continue normal operation, or go to a max ON condition (e.g., by setting the TE module voltage to about 18 Vdc and the fans 34, 36 to maximum speed). In some embodiments, alarm pull-ups can be provided to reset the alarms. The pull-ups can be referenced to the return connections of the alarms (e.g., the connections 110, 114, 118, and 122) and can have maximum parameters of about 5 milli-amperes and about 80 Vdc.
The connection 136, which is the receiving line of the serial port 48, can be connected to pin 1 of the microcontroller U10. The connection 142, which is the clock line of the I2C bus line to the memory circuit 50, can be connected to pin 2 of the microcontroller U10. The connection 138, which is the transmission line of the serial port 48, can be connected to pin 3 of the microcontroller U10. The connection 106, which is the output of the multiplexer U1 in the tachometer circuit 44, can be connected to pin 4 of the microcontroller U10. Pin 5 of the microcontroller U10 can be connected to a voltage divider circuit including the voltage V1, a resistor R58 (e.g., about 10 kilo-ohms), and a resistor R59 (e.g., about 10 kilo-ohms). The connection 160, which is an amplified voltage signal of the voltage V6 from the power monitor circuit 54, can be connected to pin 6 of the microcontroller U10. The connection 154, which is an amplified voltage signal of the voltage V3 from the power monitor circuit 54, can be connected to pin 7 of the microcontroller U10. The connection 156, which is an amplified voltage signal of the voltage V4 from the power monitor circuit 54, can be connected to pin 8 of the microcontroller U10. The connection 132, which is the enable input for the latch U4 of the alarm circuit 46, can be connected to pin 9 of the microcontroller U10. The connection 98, which is the enable input for the multiplexer U1 of the tachometer circuit 44, can be connected to pin 10 of the microcontroller U10. Pins 11, 29, 35, 16, 23, and 12, 17, 28, and 36 of the microcontroller U10 can be connected to a capacitor circuit including capacitors C9-C13 in connection with the voltage V1 (at pins 11, 29, 35, 16, and 23) and ground (at pins 12, 17, 28, and 36), with the configuration shown in
The connection 64, which is an input from the temperature sensor S4, can be connected to pin 13 of the microcontroller U10. The connection 62, which is an input from the temperature sensor S3, can be connected to pin 14 of the microcontroller U10. The connection 60, which is an input from the temperature sensor S2, can be connected to pin 15 of the microcontroller U10. The connection 58, which is an input from the temperature sensor S1, can be connected to pin 16 of the microcontroller U10. The connection 146 from the programming interface 52 can be connected to pin 19 of the microcontroller U10. The connection 104, which can lead to inputs in both the tachometer circuit 44 and the alarm circuit 46, can be connected to pin 20 of the microcontroller U10. The connection 152 from the programming interface 52 can be connected to pin 21 of the microcontroller U10. The microcontroller U10 can output a voltage V7 (described below), at pin 22, to the power circuit 41. The microcontroller U10 can output another voltage V8 (described below), at pin 23, to the power circuit 41. The microcontroller U10 can output another voltage V9 (described below), at pin 24, to the power circuit 41.
The connection 158, which is an amplified voltage signal from the voltage V5 from the power monitor circuit 54, can be connected to pin 25 of the microcontroller U10. The connection 134, which is the data input line to the latch U4 in the alarm circuit 46, can be connected to pin 26 of the microcontroller U10. The connection 100, which can lead to inputs to both the tachometer circuit 44 and the alarm circuit 46, can be connected to pin 27 of the microcontroller U10. The connection 140, which is the data line of the I2C bus line to the memory/external interface 50, can be connected to pin 30 of the microcontroller U10. The microcontroller U10 can output another voltage V10 (described below), at pin 31, to the power circuit 41. The connection 78, which is the PWM input to the first enclosure fan 36, can be connected to pin 32 of the microcontroller U10. The connection 80, which is the PWM input to the second enclosure fan 36, can be connected to pin 33 of the microcontroller U10. The connection 76, which is the PWM input to the second ambient fan 34, can be connected to pin 39 of the microcontroller U10. The connection 74, which is the PWM input to the first ambient fan 34, can be connected to pin 40 of the microcontroller U10. The connection 150 from the programming interface 52 can be connected to pin 41 of the microcontroller U10. The connection 102, which can lead to inputs to both the tachometer circuit 44 and the alarm circuit 46, can be connected to pin 42 of the microcontroller U10. The connection 144 from the programming interface 52 can be connected to pin 43 of the microcontroller U10. The connection 148 from the programming interface 52 can be connected to pin 44 of the microcontroller U10.
Following the source of the MOSFET Q7 can be an inductor-capacitor circuit including voltage clamping diode D4, a parallel inductor L1 (e.g., 47 micro-henries, rated for 2.7 amperes), and parallel capacitors C16 (e.g., 0.1 microfarads, rated for 100 volts) and C17 (e.g., 1500 microfarads, rated for 35 volts). Following the inductor-capacitor circuit can be the input line to the power in connections for the fans 34, 36 (four fans in total), and the circuit can be completed via the return power connections from the fans 34, 36 (e.g., to ground). For example, power in to the first enclosure fan 36 can be received at connection 170 and return through connection 172, power in to the second enclosure fan 36 can be received at connection 174 and return through connection 176, power in to the first ambient fan 34 can be received at connection 178 and return through connection 180, and power in to the second ambient fan 34 can be received at connection 182 and return through connection 184. In some embodiments, the tachometers (i.e., from the tachometer circuit 44) are connected to the return power connections 172, 176, 180, and 184 to determine the speed of the fans 34, 36.
A voltage divider including resistors R66 (e.g., 100 kilo-ohms) and R67 (e.g., 6.34 kilo-ohms) can provide the feedback voltage V3 to the power monitor circuit 54. The microcontroller U10 can use an amplified signal of the voltage V3 to monitor an output of the switching circuit and adjust the oscillating PWM signal (i.e., the voltage V8) accordingly. Also included after the return power connection is sensing resistor R68 (e.g., 0.005 ohms) and capacitor C18 (e.g., 0.1 microfarads, rated for 50 volts). The voltage V5 of the power return connection, can be directed to the power monitor circuit 54 for monitoring. For example, if too much current is being conducted through resistor R68, as would be seen by the voltage V5, the controller 38 can limit the input voltage V8. In addition, a voltage V11 can be monitored at the power in connections. The input voltage V8 can be a fixed voltage and can regulate a desired output voltage to the fans 34, 36 within about +/−1.0 Vdc. In some embodiments, the desired output voltage at the power in connections to the fans 34, 36 can be about 12.0 Vdc, with an output current up to about 2.7 amperes.
As shown in
The resistors R69, R73, and R75 can be about 2.1 kilo-ohms, the resistors R70 and R71 can be about 1 kilo-ohm, the resistor R72 can be about 330 ohms, and the resistor R74 can be about 100 kilo-ohms. The capacitor C20 can be about 1.0 microfarads (rated for 100 volts) and the zener diode D8 can have a 15-volt breakdown voltage. The switcher circuit can also include resistors R76 (e.g., 47.5 kilo-ohms), R77 (10 kilo-ohms), R78 (15 ohms), and C21 (47 microfarads, rated for 25 volts).
Following the source of the MOSFET Q10 can be an inductor-capacitor circuit including voltage clamping diode D9, a parallel inductor L2 (e.g., 220 micro-henries, rated for 27 amperes), and parallel capacitors C22 (e.g., 0.1 microfarads, rated for 100 volts), C23 (e.g., 2700 microfarads, rated for 35 volts), and C24 (e.g., 2700 microfarads, rated for 35 volts). Following the inductor-capacitor circuit can be a voltage divider including resistors R79 (e.g., 100 kilo-ohms) and R80 (e.g., 6.34 kilo-ohms) that provides the feedback voltage V4 to the power monitor circuit 54. The microcontroller U10 can use an amplified signal of the voltage V4 to monitor an output of the switching circuit and adjust the oscillating PWM signal (i.e., voltage V7) accordingly. Also following the inductor-capacitor circuit are resistor R81 (e.g., 0.002 ohms), resistor R82 (e.g., 0.002 ohms) and capacitor C25 (e.g., 0.1 microfarads, rated for 50 volts). The inductor-capacitor circuit, through the resistors R81-R82 and the capacitor C25, leads to the connections 186 and 188.
As shown in
The resistors R82, R86 and R88 can be about 330 ohms, the resistors R83, R85, R87, and R89 can be about 2.1 kilo-ohms, the resistor R84 can be about 100 kilo-ohms, and the resistor R74 can be about 100 kilo-ohms. The capacitors C28 and C29 can be about 1.0 microfarads (rated for 100 volts) and the zener diodes D16 and D17 can have a 15-volt breakdown voltage. The identical circuits can also include resistors R90 and R91 (e.g., both 10 kilo-ohms) and resistors R92 and R93 (15 ohms).
One of the two identical circuits can be switched on, while the other is switched off, and vice versa, to provide forward or reverse polarity power to the TE modules 26, allowing the TE management unit 10 to work in a cooling mode or a heating mode. The microcontroller U10 can control such switching via the input voltage V9, as described below.
When the input V9 is high, current can flow through a resistor R94 (e.g., 10 kilo-ohms), through the base to the emitter of transistor Q16 to ground. This also can allow current flow from voltage source V1 through a resistor R95 (e.g., 330 ohms), through the collector of the transistor Q16 to ground. As a result, no current flows to the base of transistor Q17 and it is not active. Because the transistor Q17 is not active, no current is being pulled through the resistor R90 to the collector of transistor Q17, and thus, no voltage is provided to turn on the high-side gate driver U13. In addition, when the input V9 is high, current can flow through a resistor R96 (e.g., 330 ohms), through the base to the emitter of transistor Q18 to ground. This pulls current from voltage V2 through the resistor R91, through the collector of the transistor Q18 to ground, which then allows a voltage to be provided to the high-side gate driver U14, thus turning it on. Therefore, when the input V9 is high, the high-side gate driver U13 is off and the high-side gate driver U14 is on.
When the input V9 is low, the transistor Q16 is not in active mode, and thus, current can flow from voltage source V1 through the resistor R95 to turn on the transistor Q17, which in turn pulls current from voltage source V2 through the resistor R90, allowing the high-side gate driver U13 to turn on. Also, when the input V9 is low, the transistor Q18 is not in active mode, and thus, no voltage is provided to the high-side gate driver U14. Therefore, when the input V9 is low, the high-side gate driver U13 is on and the high-side gate driver U14 is off.
When the high-side gate driver U13 is on, voltage is applied to switch on the MOSFET Q12, which in turn provides voltage (from connection 186) supplied to the TE modules 26 at the connections 190 and 192. Also, when the high-side gate driver U13 is on, voltage from V2 is applied across a the resistor R90 and a resistor R97 (e.g., 10 kilo-ohms) to ground, which can switch on a MOSFET Q19. The active MOSFET Q19 provides a return line from the TE modules 26 (at the connections 194 and 196) to ground. While in this configuration, the TE management unit 10 can be in a cooling mode.
When the high-side gate driver U14 is on, voltage is applied to switch on the MOSFET Q13, which in turn provides voltage (from connection 186) supplied to the TE modules 26 at the connections 194 and 196. Also, when the high-side gate driver U14 is on, voltage from V2 is applied across the resistor R91 and a resistor R98 (e.g., 10 kilo-ohms) to ground, which can switch on a MOSFET Q20. The active MOSFET Q20 then provides a return line from the TE modules 26 (at the connections 190 and 192) to ground. While in this configuration, the TE management unit 10 can be in a heating mode.
In some embodiments, the high-side gate drivers U11-U14 can each be Part No. FAN7361, manufactured by Fairchild Semiconductor®, the transistors Q5, Q6, Q8, Q9, Q15, Q16, Q17 and Q18 can be NPN transistors, such as Part No. MMBTH24, manufactured by Fairchild Semiconductor®, and the MOSFETs Q7, Q10, Q12, Q13, Q19, and Q20 can be Part No. IRF520NPBF, manufactured by International Rectifier.
The voltage V6 at connections 194 and 196 can be directed to the power monitor circuit 54 for monitoring. In addition, a voltage V12 can be monitored at the connections 190 and 192. The input voltage V7 (as shown in
The unit power circuit 166 can have a series of filtering capacitors C30-C33, followed by a voltage regulator U15, such as a high voltage step down switching regulator (e.g., Part No. LM5008, manufactured by National Semiconductor). The filtering capacitors C30, C31, C32, and C33 can have a capacitance of 0.001 microfarads, 0.001 microfarads, 10 microfarads, and 0.1 microfarads, respectively, and can all be rated for 100 volts. The input voltage, after diode D18, can be connected to pin 8 of the regulator U15. The input voltage can also be connected to pin 6, with a resistor R99 (e.g., 232 kilo-ohms) in between. Pins 3, 7, and 4 can be connected to the return line, with a resistor R100 (e.g., 232 kilo-ohms) between pin 3 and the return line, and a capacitor C34 (e.g., 0.1 microfarads, rated for 50 volts) between pin 7 and the return line. Pin 1 of the regulator U15, through inductor L3 (e.g., 470 micro-Henries, rated for 0.79 amperes), outputs the voltage V2 for the TE management unit 10. A feedback voltage from a voltage divider including the voltage V2 and resistors R101 (e.g., 10 kilo-ohms) and R102 (e.g., 2550 ohms) can be fed back to pin 5 of the regulator U15. Also, pin 2 of the regulator U15 can be connected to the output of pin 1, with capacitor C35 (e.g., 0.01 microfarads) in between, followed by diode D19, connected to ground.
The voltage V2 is connected to another voltage regulator U16 to produce the voltage V1 Transient protection capacitors C36-C39 can also be present before and after the regulator U16. The output of the regulator U16, connected through a resistor R103 to ground, can be the voltage V1 for the TE management unit 10. A fuse F1 can be provided before voltage source V1 to prevent current overload. The fuse F1 can be a resettable fuse (i.e., a PTC). In some embodiments, the capacitors C36, C37, C38, and C39 can have a capacitance of 47 microfarads (rated for 25 volts), 0.1 microfarads (rated for 50 volts), 10 microfarads (rated for 6.3 volts), and 0.1 microfarads (rated for 50 volts), respectively. The voltage regulator U16 can be Part No. LD1117DT, manufactured by ST Microelectronics.
In addition, the input voltage, after diode D18, can be provided to the fan power circuit 162 and the TE power circuit 164, via the connection 168. A bulk capacitor C40 (e.g., 4700 microfarads, rated for 80 volts) can be connected to the connection 168 to provide power to the fan power circuit 162 and the TE power circuit 164 in case of any transients at the input connections 198 and 200.
The wiring diagram of
If, at step 210 the loop count is greater than the preset integer, the controller 38 proceeds to step 226 and calculates various temperatures and voltages, checks the temperature sensors S1-S4 for any faults, and increments the loop counter. Following either step 222 or 226, the controller 38 proceeds to step 228 (
If, at step 266, there are no alarms active, the controller 38 determines, at step 276, if the air loop temperature change is greater than the fan change setpoint. If not, the PWM step change value is subtracted from the PWM signals at step 278. If so, the PWM step change value is added to the PWM signals at step 280. Following either step 278 or 280, the controller 38 proceeds to step 270 (described above).
If, at step 248, the controller 38 determines that the fans 34, 36 are not in a “run” mode, the controller 38 determines if the fans 34, 36 are in an “off” mode at step 282. If the fans 34, 36 are in the off mode, the controller 38 proceeds to step 284 and sets the PWM signals to 0%, then proceeds to step 272. If the controller 38 determines at step 282 that the fans are not in off mode, the controller 38 proceeds straight to step 272.
If, at step 292, the controller 38 determines that the enclosure temperature is not greater than the cool temperature setpoint, the controller 38 proceeds to step 304 and determines if the enclosure inlet temperature is less than a warm temperature setpoint. If so, the controller 38 sets the TE management unit 10 to the heating mode at step 306, then proceeds to step 296. If not, the controller 38 does nothing and proceeds to step 296 and determines if the air loop temperature change is greater than a maximum air loop temperature change.
If, at step 296, the controller 38 determines that the air loop temperature change is not greater than a maximum air loop temperature change, the controller 38 proceeds to step 308. At step 308, the controller 38 sets and records a setpoint error value as the difference between the enclosure temperature and the temperature setpoint, then sets a “sum of setpoint errors” value as the sum of the last 16 setpoint error values recorded. If the sum of setpoint errors value is above a maximum value, the controller 38 limits the sum of setpoint errors value to the maximum value. The controller 38 then sets a voltage adjust value as the product of a constant Kp and the setpoint error value plus a product of another constant Ki and the sum of setpoint errors value. The controller 38 then proceeds to step 310 and determines if the TE management unit 10 is in cooling mode. If so, the controller 38 proceeds to step 312 and adds the voltage adjust value to the current TE voltage output value. If not, the controller 38 proceeds to step 314 and subtracts the voltage adjust value from the current TE voltage output value. Following either step 312 or step 314, the controller 38 determines if an enclosure temperature alarm (e.g., the temperature or sensor failure alarm or the airflow alarm) is active at step 316. If so, the controller 38 sets the TE voltage output to 18 Vdc at step 318. If there is no enclosure temperature alarm active at step 316, or following step 318, the controller 38 determines if a fan alarm (e.g., the airflow alarm or the power fault alarm) is active at step 320. If so, the controller 38 sets the TE voltage output to 0 volts at step 322. If there is no fan alarm active at step 320, or following step 322, the controller 38 proceeds to step 300 and confirms the TE voltage output is within a range of greater than or equal to 0 volts and less than or equal to 24 volts, and adjusts the TE voltage output accordingly if it is not. Following step 300, the ISR is completed at step 302. The temperature set points in steps 292 and 304 can be factory-set or adjusted through a programming interface (e.g., the programming interface 52), display board, or other user interface by a user. Also, in some embodiments, if the TE management unit 10 is between temperature set-points upon startup, the controller 38 can default to heating mode.
In some embodiments, as shown in
The separator PCB 358 can be custom-made, and thus, can be populated with different electronic circuits that perform several different functions, such as control, regulation, monitoring, etc. of the TE management unit 10.
The separator PCB 358 can provide some or all of the electrical and electronic connections for the controller 38 and the elements of the TE management unit 10. For example, the separator PCB 358 can include some or all elements necessary to perform the same functions of the control circuit 39 and power circuit 41 described above (i.e., at least the functions described in flow charts 13A-13G). Thus, the separator PCB 358 can allow for the TE modules 26 as well as other components of the TE management unit 10 to reliably connect and interconnect on the traces of the PCB, rather than using separate circuitry and connectors. The separator PCB 358 can integrate circuitry without the need, or with minimal need, for external housings or junction boxes.
Pins 6, 11, 13, 14, and 21 of the controller U19 can be connected to ground. Pins 6, 14, and 21 can also be connected to the voltage V13 with the capacitor C56 in between. Pin 7 of the controller U19 can be connected to ground with a capacitor C60 (e.g., 0.01 microfarads) in between. Pins 8 and 9 of the controller U19 can be connected to the output of the controller U19 at pin 10. For example, pin 8 can be a feedback input. A compensation loop connected between pins 8 and 9 can include a resistor R118 (e.g., 27.4 kilo-ohms) and capacitors C61 (e.g., 0.01 microfarads) and C62 (e.g., 1 kilopicofarad). The compensation loop can be connected to pin 10 via feedback resistors R119 (e.g., 16.4 kilo-ohms), R120 (e.g., 650 ohms), R121 (e.g., 180 ohms), and high power jumper J3 in connection with ground.
The bulk power regulator 368 further includes a pair of MOSFETs Q21 and Q22. The source of MOSFET Q21 and the drain of MOSFET Q22 can be connected. Pins 19 and 15 of the controller U19 can be connected to the gates of the MOSFETs Q21 and Q22, respectively. The drain of MOSFET Q21 can be connected to the voltage V13. The source of MOSFET Q22 and pin 12 of the buck controller U19 can be connected to ground with a resistor R122 (e.g., 0.005 ohms, rated for 1 watt) in between. Pins 16, 18, and 20 of the controller U19 can be connected between the source of MOSFET Q21 and the drain of MOSFET Q22 via resistor R123, a diode D26, and a capacitor C63. Also connected between the source of MOSFET Q21 and the drain of MOSFET Q22 can be the output from pin 10 of the controller U19 with an inductor L6 in between, followed by an output capacitor bank C64, leading to the regulated, direct current voltage V16. The output capacitor bank C64 can include ten 10-microfarad capacitors, all rated for 35 volts, and can be followed by another capacitor C65 (e.g., 680 microfarads, rated for 35 volts). The bulk power regulator 368 can further include an input capacitor bank, including capacitors C66, C67, C68, and C69 (each 2.2 microfarads, rated for 100 volts) connected to the voltage V13. In addition, the voltage V15, from the connection 380 can be connected to the input pin 17. The input pin 17 can further be connected to ground through a capacitor C70 for transient filtering.
The resistors R124 and R127 can be about 2.0 kilo-ohms, the resistors R125 and R128 can be about 1 kilo-ohm, and the resistors R126 and R129 can be about 470 ohms. The capacitors C73 and C74 can be about 1.0 microfarads (rated for 100 volts). The identical circuits can also include resistors R130 and R131 (e.g., each 10 kilo-ohms), resistors R132 and R133 (e.g., each 15 ohms), and capacitors C75 and C76 (e.g., each 10 microfarads, rated for 16 volts).
One of the two identical circuits can be switched on, while the other is switched off, and vice versa, to provide forward or reverse polarity power to the TE modules 26, allowing the TE management unit 10 to work in a cooling mode or a heating mode. The control circuit 361 can control such switching via the input voltages V18 and V19, as described below.
When the voltage V18 is high, current can flow through a resistor R134 (e.g., 470 ohms), through the base to the emitter of transistor Q27 to ground. This pulls current from voltage V15 through the resistor R131, through the collector of the transistor Q27 to ground, which then allows a voltage to be provided to the high-side gate driver U21, thus turning it on. In addition, when voltage V18 is high, voltage V19 can be low. When voltage V19 is low, no current travels to the base of transistor Q28 and it is not active. Because the transistor Q28 is not active, no current is being pulled through the resistor R128 to the collector of transistor Q28, and thus, no voltage is provided to turn on the high-side gate driver U20. Therefore, when the voltage V18 is high and the voltage V19 is low, the high-side gate driver U20 is off and the high-side gate driver U21 is on. Also, the voltage V14 can be provided at the output of voltage V18 with a resistor R135 (e.g., 232 kilo-ohms) in between.
When the voltage V18 is low, the transistor Q27 is not in active mode, and thus, no voltage is provided to the high-side gate driver U21. Also, when the voltage V18 is low, the voltage V19 is high, and current is allowed to flow through the transistor Q28, which in turn pulls current from voltage source V15 through the resistor R130, allowing the high-side gate driver U20 to turn on. Therefore, when the voltage V18 is low and the voltage V19 is high, the high-side gate driver U20 is on and the high-side gate driver U21 is off.
When the high-side gate driver U20 is on, voltage is applied to switch on the MOSFET Q23, which in turn provides voltage V16 supplied to the TE modules 26 (i.e., at voltage V20). Also, when the high-side gate driver U20 is on, voltage from V15 is applied across a the resistor R130 and a resistor R136 (e.g., 232 kilo-ohms) to ground, which can switch on a MOSFET Q29. The active MOSFET Q29 provides a return line from the TE modules 26 (i.e., voltage V21) to ground. While in this configuration, the TE management unit 10 can be in a cooling mode. Also, the voltage V14 can be provided at the output of voltage V19 with a resistor R137 (e.g., 232 kilo-ohms) in between.
When the high-side gate driver U21 is on, voltage is applied to switch on the MOSFET Q24, which in turn provides voltage V16 supplied to the TE modules 26 (i.e., at voltage V21). Also, when the high-side gate driver U21 is on, voltage from V15 is applied across the resistor R129 and a resistor R138 (e.g., 232 kilo-ohms) to ground, which can switch on a MOSFET Q30. The active MOSFET Q30 then provides a return line from the TE modules 26 (i.e., voltage V20) to ground. While in this configuration, the TE management unit 10 can be in a heating mode.
Both the voltages V18 and V19 can be pulse-width modulated by the controller 38. In some embodiments, the high-side gate drivers U20-U21 can each be Part No. FAN7361, manufactured by Fairchild Semiconductor®, the transistors Q25, Q26, Q27 and Q28 can be NPN transistors, such as Part No. MMBTH24, manufactured by Fairchild Semiconductor®, and the MOSFETs Q23, Q24, Q29, and Q30 can be Part No. IRF520NPBF, manufactured by International Rectifier. In addition, the voltage V16 and ground can each be connected to the earth ground reference via capacitors C77 and C78.
The first sensor circuit, including sensor 55, can be routed to the microcontroller circuit 410 via a connection 412. The second sensor circuit, including sensor S6, can be routed to the microcontroller circuit 410 via a connection 414. The third sensor circuit, including sensor S7, can be routed to the microcontroller circuit 410 via a connection 416. The fourth sensor circuit, including sensor S8, can be routed to the microcontroller circuit 410 via a connection 418. In addition, an external sensor circuit, including resistors R151 (e.g., 10 kilo-ohms) and R152 (e.g., 3.46 kilo-ohms), and capacitor C83 (e.g., 01 microfarad) can be connected to the microcontroller circuit 410 via a connection 420. The external sensor circuit can accompany an external sensor S9, which may be, for example, a door switch or a smoke detector. The external sensor S9 can receive power from the voltage V15.
One of the temperature sensors (S5, for example) can be positioned at the enclosure inlet 11 and another temperature sensor (S6, for example) can be positioned at the enclosure outlet 13. A third temperature sensor (S7, for example) can be positioned at the ambient inlet 15 and a fourth temperature sensor (S8, for example) can be positioned at the ambient outlet 17. Therefore, temperatures can be sensed at both the inlets and outlets of the enclosure air loop and the ambient air loop. The temperature sensors S5-S8 can have a temperature accuracy of about +/− 2 degrees Celsius.
The controller 38 can independently speed control each of the four fans 34, 36 separately. To speed control the first ambient fan 34 (via connection 422), a PWM signal from the microcontroller circuit 410 is transmitted to a resistor R153 via a connection 430 and can switch on and off a transistor Q31. The base of the transistor Q31 can be connected to the resistor R153 and the emitter of the transistor Q31 can be connected to ground. When the signal from connection 430 applies a substantial cut-in voltage across the base-emitter junction, the transistor Q31 becomes active and allows current flow from the collector to the emitter. This current is conducted from the voltage source V15, through resistors R154 and R155, and through the collector and the emitter to ground. The connection 422 is connected between the resistors R154 and R155 to provide the PWM input to the first ambient fan 34 when the transistor Q31 is on. This method and configuration is also used to speed control the second ambient fan 34, and the first and second enclosure fans 36 as well, via signals through connections 432, 434, and 436, respectively, from the microcontroller circuit 410, as illustrated in
The multiplexer U22 can be an 8-input multiplexer, such as Part No. 74HC151, manufactured by Philips Semiconductors. Pins 1-4, which can be coupled to connections 438, 440, 442, and 444 can be multiplexer inputs of U2. Pins 12-15 can also be multiplexer inputs and can receive outputs from various override devices (not shown), such as smoke detectors, door switches, etc., which the controller 38 can monitor. When none of pins 12-15 are connected to override devices, as illustrated in
As shown in
The latch U23 can also output signals to communicate alarm outputs with a remote device (not shown). For example, pin 9 can be connected to the remote device at connections 468, 470, and 472 via the circuit including resistor R177 (e.g., 470 ohms), diode D33, transistor Q35, reference voltage V15 and signal relay U24. The signal relay U24 can have both normally open and normally closed contacts, allowing alarm outputs to be communicated to the remote device in a zero potential circuit.
The latch U23 can be an 8-bit addressable latch, such as Part No. 74HC259, manufactured by Philips Semiconductors. Address inputs to pins 1, 2, and 3 can be from input voltages V23, V24, and V25, respectively, from the microcontroller circuit 410. An enable input to pin 14 can be from input voltage V26 from the microcontroller circuit 410. Pin 15 can be a conditional reset input, which is active when low, and can be connected to voltage V15. Pin 13 can receive input data from the microcontroller circuit 410 via an input voltage V27. The output voltages at pins 10, 11, and 12 (voltages V28, V29 and V30, respectively) can be routed to the tachometer circuit 402 via the connections 446, 448, and 450.
The memory/external ports circuit 406 can also include a memory chip U25 and connection port J4. The memory chip U25 can be a SEEPROM (serial EEPROM) chip. The connection port J4 can be used to connect an external device, such as a display board. “I2C” communications can be used for communication between the microcontroller circuit 410, the memory chip U25, and the connection port J4 via connections 486 and 488. For example, I2C communications can be used with the memory chip U25 for loading and storing controller runtime variables and logging faults. In some embodiments, connection 488 can be the data line and connection 486 can be the clock line. Also, resistors R178 and R179 (both about 1 kilo-ohm) can be included in the memory/external ports circuit 406, connecting voltage V14 to connections 486 and 488, respectively. In addition, when not connected to an external device, the connection port J4 can be connected to voltages V14 and V15 with filtering capacitors C88-C93. The capacitors C88, C89, C91, and C92 each can have a capacitance of about 1 microfarad and the capacitors C90 and C93 each can have a capacitance of about 10 microfarads, rated for 16 volts.
The memory/external ports circuit 406 can further include a connection port (including connections 490, 492, 494, and 496) for remote devices, such as slave units. For example, input to the remote unit, at the connection 494, can come from the microcontroller circuit 410 via a connection 498. Output from the remote unit, at the connection 492, can be routed to the microcontroller circuit 410 via a connection 500. A pull-up voltage, such as voltage V14 can be connected to the remote unit at the connection 490, and a return from the remote unit, at the connection 496, can lead to ground. The connection port can include resistors R182 (e.g., 100 kilo-ohms), R183 (e.g., 1 kilo-ohm), R184 (e.g., 1 kilo-ohm), and capacitor C94 (e.g., 0.1 microfarads).
The connection 482, which is the receiving line of the serial port in the memory/external ports circuit 406, can be connected to pin 1 of the microcontroller U26. The connection 488, which is the data line of the I2C bus line to the memory/external ports circuit 406, can be connected to pin 2 of the microcontroller U26. The connection 484, which is the transmission line of the serial port in the memory/external ports circuit 406, can be connected to pin 3 of the microcontroller U26. Pin 4 of the microcontroller U26 can output voltage V25, which can transmitted to the latch U23 in the alarm circuit 404. Pin 5 of the microcontroller U26 can receive voltage V22, which is the output from the multiplexer U22 in the tachometer circuit 402. The connection 498, which is input line to the remote unit in the memory/external ports circuit 406 can be connected to pin 6 of the microcontroller U26. The connection 420, which is an input from the sensor S9 of the temperature sensors circuit 398, can be connected to pin 7 of the microcontroller U26. Pins 8, 9, 10, 37, and 38 of the microcontroller U26 can be open. Pins 11, 29, 35, 16, 23, and 12, 17, 28, and 36 of the microcontroller U10 can be connected to a capacitor circuit including capacitors C95-C99 in connection with the voltage V14 (pins 11, 29, 35, 16, and 23) and ground (pins 12, 17, 28, and 36), with the configuration shown in
The connection 418, which is an input from the temperature sensor S8, can be connected to pin 13 of the microcontroller U26. The connection 416, which is an input from the temperature sensor S7, can be connected to pin 14 of the microcontroller U26. The connection 414, which is an input from the temperature sensor S6, can be connected to pin 15 of the microcontroller U26. The connection 412, which is an input from the temperature sensor S5, can be connected to pin 16 of the microcontroller U26. The connection 504 from the programming interface 408 can be connected to pin 19 of the microcontroller U26. Pin 20 of the microcontroller U26 can output voltage V26, which can transmitted to the latch U23 in the alarm circuit 404. The connection 510 from the programming interface 408 can be connected to pin 21 of the microcontroller U26. Pins 22, 23, 24, 27, and 31 of the microcontroller U26 can output the voltages V24, V23, V17, V18, and V19, respectively, which can all be transmitted to the power circuit 360.
Pin 25 of the microcontroller U26 can output voltage V27, which can be transmitted to the latch U23 in the alarm circuit 404. The connection 500, which is input from to the remote unit in the memory/external ports circuit 406 can be connected to pin 26 of the microcontroller U26. The connection 486, which is the clock line of the I2C bus line to the memory/external ports circuit 406, can be connected to pin 30 of the microcontroller U26. The connections 430, 432, 434, and 436 from the fan speed control circuit 400 can be connected to pins 40, 39, 32, and 33, respectively, of the microcontroller U26. The connections 508, 502, and 506 from the programming interface 408 can be connected to pins 41, 43, and 44, respectively, of the microcontroller U26. In addition, the connection 512 from the SS Relay Drive 409 can be connected to pin 42 of the microcontroller U26.
It will be appreciated by those skilled in the art that while the invention has been described above in connection with particular embodiments and examples, the invention is not necessarily so limited, and that numerous other embodiments, examples, uses, modifications and departures from the embodiments, examples and uses are intended to be encompassed by the claims attached hereto. The entire disclosure of each patent and publication cited herein is incorporated by reference, as if each such patent or publication were individually incorporated by reference herein. Various features and advantages of the invention are set forth in the following claims.
Claims
1. A thermal management unit for an enclosure, the thermal management unit comprising:
- a housing;
- at least one fan to direct air flow through the housing;
- a plurality of thermoelectric modules;
- at least one heat sink assembly coupled to the plurality of thermoelectric modules;
- a controller providing power to the plurality of thermoelectric modules; and
- a printed circuit board incorporating the plurality of thermoelectric modules and electrically connecting the plurality of thermoelectric modules to the controller, the printed circuit board separating an ambient side of the thermal management unit and an enclosure side of the thermal management unit.
2. The thermal management unit of claim 1 wherein the plurality of thermoelectric modules comprises a first plurality of thermoelectric modules positioned in an area of higher air flow in the housing and a second plurality of thermoelectric modules position in an area of lower air flow in the housing, wherein the controller provides higher power to the first plurality of thermoelectric modules and lower power to the second plurality of thermoelectric modules.
3. The thermal management unit of claim 1 wherein the controller further provides power to the at least one fan using pulse width modulation.
4. The thermal management unit of claim 3 wherein the controller modulates the speed of the at least one fan in substantially real-time.
5. The thermal management unit of claim 4 wherein the at least one fan includes at least one enclosure fan positioned in the enclosure side of the thermal management unit and at least one ambient fan positioned in the ambient side of the thermal management unit, wherein the controller individually modulates the speed of the at least one enclosure fan and the at least one ambient fan separately.
6. The thermal management unit of claim 1 wherein the at least one heat sink assembly includes an ambient heat sink on the ambient side of the thermal management unit and an enclosure heat sink on the enclosure side of the thermal management unit.
7. The thermal management unit of claim 1 wherein the at least one fan includes an ambient fan on the ambient side of the thermal management unit and an enclosure air fan on the enclosure side of the thermal management unit.
8. The thermal management unit of claim 1 wherein the controller provides regulated voltage levels to the plurality of thermoelectric modules.
9. The thermal management unit of claim 1 wherein the plurality of thermoelectric modules includes one of four, eight, twelve, and sixteen thermoelectric modules.
10. The thermal management unit of claim 1 wherein the ambient side of the thermal management unit and the enclosure side of the thermal management unit are positioned inside the enclosure, and the ambient side is in communication with air outside the enclosure.
11. The thermal management unit of claim 1 wherein the ambient side of the thermal management unit is positioned outside of the enclosure and the enclosure side of the thermal management unit is positioned inside of the enclosure.
12. The thermal management unit of claim 1 wherein the ambient side of the thermal management unit and the enclosure side of the thermal management unit are positioned outside the enclosure, and the enclosure side is in communication with air inside the enclosure.
13. The thermal management unit of claim 1 further comprising a thermal transfer material applied at an interface between the plurality of thermoelectric modules and the at least one heat sink assembly.
14. The thermal management unit of claim 1 further comprising a tachometer to measure a speed of the at least one fan, the tachometer being in communication with the controller.
15. The thermal management unit of claim 1 wherein the printed circuit board includes electrical connections to at least electrically connect the controller to the plurality of thermoelectric modules, the electrical connections being positioned on the enclosure side of the thermal management unit.
16. The thermal management unit of claim 1 further comprising at least one temperature sensor in communication with the controller.
17. The thermal management unit of claim 16 wherein the at least one temperature sensor is a thermistor and is positioned to monitor temperature of the air flow through the housing.
18. The thermal management unit of claim 17 wherein the at least one temperature sensor is positioned along at least one of an inlet of the ambient side of the thermal management unit, an outlet of the ambient side of the thermal management unit, an inlet of the enclosure side of the thermal management unit, and an outlet of the enclosure side of the thermal management unit.
19. The thermal management unit of claim 1 wherein the controller is adapted to change a polarity of the power to the plurality of thermoelectric modules.
20. The thermal management unit of claim 1 further comprising an alarm in communication with the controller, the alarm being activated by the controller when the controller senses a fault in the thermal management unit.
21. The thermal management unit of claim 20 wherein the alarm includes at least one of a visual alarm and an audio alarm.
22. The thermal management unit of claim 1 further comprising an external communication link connected to the controller.
23. The thermal management unit of claim 1 further comprising one of an RS-232 port, an I2C communications port, an RS-485 port, a USB port, and an ETHERNET port connected to the controller
24. A thermal management unit for an enclosure, the thermal management unit comprising:
- a housing;
- at least one fan to direct air flow through the housing;
- a first plurality of thermoelectric modules positioned in an area of higher air flow in the housing;
- a second plurality of thermoelectric modules position in an area of lower air flow in the housing;
- a first heat sink assembly coupled to the first plurality of thermoelectric modules;
- a second heat sink assembly coupled to the second plurality of thermoelectric modules; and
- a controller providing power to the first plurality of thermoelectric modules and the second plurality of thermoelectric modules, the controller providing a higher power to the first plurality of thermoelectric modules and a lower power to the second plurality of thermoelectric modules.
25. The thermal management unit of claim 24 further comprising a printed circuit board incorporating the first plurality of thermoelectric modules and the second plurality of thermoelectric modules, the printed circuit board electrically connecting the first plurality of thermoelectric modules and the second plurality of thermoelectric modules to the controller, the printed circuit board separating an ambient side of the thermal management unit and an enclosure side of the thermal management unit.
26. A thermal management unit for an enclosure, the thermal management unit comprising:
- a housing;
- at least one fan to direct air flow through the housing;
- a plurality of thermoelectric modules;
- at least one heat sink assembly coupled to the plurality of thermoelectric modules;
- a controller providing regulated power independently to at least one of the plurality of thermoelectric modules to optimize thermal management unit performance; and
- a printed circuit board incorporating the plurality of thermoelectric modules and electrically connecting the plurality of thermoelectric modules to the controller, the printed circuit board separating an ambient side of the thermal management unit and an enclosure side of the thermal management unit.
27. A thermal management unit for an enclosure, the thermal management unit comprising:
- a housing;
- at least one fan to direct air flow through the housing;
- a plurality of thermoelectric modules;
- at least one heat sink assembly coupled to the plurality of thermoelectric modules;
- a controller providing power independently to at least one of the at least one fan to vary airflow to the plurality of thermoelectric modules and the at least one heat sink assembly to optimize thermal management unit performance; and
- a printed circuit board incorporating the plurality of thermoelectric modules and electrically connecting the plurality of thermoelectric modules to the controller, the printed circuit board separating an ambient side of the thermal management unit and an enclosure side of the thermal management unit.
Type: Application
Filed: Jan 22, 2010
Publication Date: Nov 11, 2010
Inventors: John Myron Rawski (Plymouth, MN), Larry Allen Larson (Rogers, MN), Jason William Dickmann (Champlin, MN), Pedro Ramon Guitart (Lakeville, MN), Joseph David Ricke (Arden Hills, MN), William James Hanson (Edina, MN), Alan Frank Wells (Anoka, MN)
Application Number: 12/692,489
International Classification: F25B 21/02 (20060101);