Thermal management system

Abstract

Simple, compact, lightweight thermal management system offering reduced inventory of heat transfer fluid. The invention provides heat transfer fluid at a very high flow rate to a heat exchanger. A portion of the heat transfer fluid flow downstream of the heat exchanger is separated and pumped by a fluid-dynamic pump back into the heat exchanger. The fluid dynamic pump is operated by a fresh heat transfer fluid supplied at high-pressure. Because a substantial portion of the flow leaving the heat exchanger is recirculated back to the inlet, the amount of fresh heat transfer fluid consumed is substantially reduced compared to a traditional system. Uses of the invention include cooling of devices at very high heat flux including photovoltaic cells, solar panels, semiconductor laser diodes, semiconductor electronics, and laser gain medium. Other uses of the invention include systems, for refrigeration, air conditioning, and gas liquefaction.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from U.S. provisional patent application U.S. Ser. No. 60/936,505, filed Jun. 20, 2007; U.S. provisional patent application U.S. Ser. No. 61/011,691, filed Jan. 18, 2008; U.S. provisional patent application U.S. Ser. No. 61/066,249, filed Feb. 19, 2008; and U.S. provisional patent application U.S. Ser. No. 61/130,419, filed May 31, 2008.

FIELD OF THE INVENTION

This invention relates generally to systems for thermal management and more specifically to supplying a fluid to a heat exchanger for thermal management.

BACKGROUND OF THE INVENTION

There are many devices which require thermal management. Frequently, thermal management is administered by flowing suitable heat transfer fluid (HTF) through a heat exchanger (HEX) in thermal communication with a device requiring thermal management action, which such as cooling or heating. Depending on the desired effect, the HTF may supply heat to the device or remove heat from it. To obtain high heat transfer effect, HTF may be flowed through the HEX at very high velocity. This may be particularly important in applications where heat is provided from a device to the HEX at very high heat flux, such as may be practiced in solar photovoltaic cells used with concentrator, thermal photovoltaic cells, laser gain medium, semiconductor laser diodes, and semiconductor electronics. To meet such thermal management needs, the HEX may have to be supplied with HTF at very high flow rates. In a traditional thermal management system of prior art, the required high flow rate of HTF through the HEX may be sustained by supplying fresh HTF at the same high flow rate. This necessitates a large thermal management system including large piping, valves, and pumps. As a result, a traditional thermal management system may be large in volume and weight, which makes it less suitable for applications requiring compactness and lightweight.

One frequent consequence of providing HTF at very high flow rates is that the HTF temperature may not change much more than a few degrees Centigrade after passing though the HEX. This leads to a low utilization of HTF. In addition, a traditional thermal management system of prior art may require a large amount of energy to operate. This situation may be challenging in energy sensitive applications such as when cooling photovoltaic cells used with concentrator, thermal photovoltaic cells, or removing heat from solar panels.

Furthermore, a traditional thermal management system may require a large amount of HTF inventory. In the event of an accidental HTF release from the system, such a large HTF inventory may pose significant safety, health, and environmental hazards. In addition, a large HTF inventory has a large inertia, which must be overcome during flow start and stop conditions. The above size, weight, energy consumption, HTF inventory, and inertia characteristics of traditional thermal management system may make it less desirable in applications requiring compactness, lightweight, reduced energy consumption, improved safety, and fast startup.

SUMMARY OF THE INVENTION

The subject invention provides a simple, compact, lightweight thermal management system offering reduced HTF inventory and energy consumption. In particular, the subject invention provides HTF at a very high flow rate to a HEX in thermal communication with a device requiring thermal management. A portion of the HTF flow downstream of the HEX outlet is separated and pumped by a fluid-dynamic pump back into the HEX inlet. The fluid dynamic pump is operated by a fresh HTF supplied at high-pressure that may be provided by a pump, a high-pressure tank, or other suitable source. Because a substantial portion of the flow leaving the HEX is recirculated back to the HEX inlet, the amount of fresh HTF consumed is substantially reduced compared to a traditional thermal management system. A portion of the HTF downstream of the HEX that is not recirculated back to the HEX may be fed to the suction port of a pump, or stored in a tank or an accumulator, or it may be released from the thermal system. See, for example, a publication entitled “Improved Cooling for High-Power Laser Diodes,” authored by John Vetrovec in proceedings from Photonics West, San Jose, Calif., Jan. 20-24, 2008, SPIE vol. 6876, and “Lightweight and Compact Thermal Management System for Solid-State High-Energy Laser,” in proceedings from the 21^st Annual Solid-State and Diode Technology Review, held in Albuquerque, NM, Jun. 3-5, 2008, both of which are hereby expressly incorporated by reference in their entirety.

If the HTF provided to the driving nozzle of the fluid dynamic pump is substantially in a gas or vapor form, the fluid dynamic pump may be an ejector. If the HTF provided to the driving nozzle of the fluid dynamic pump is substantially is in a liquid form, the fluid dynamic pump may be a jet pump.

In one preferred embodiment of the subject invention, the thermal management system may use HTF in a substantially liquid form supplied by a supply tank pressurized by pressurant gas at a higher pressure and collected in a receiving tank that may be pressurized by pressurant gas at a lower pressure. HTF temperature may be changed in a suitable secondary heat exchanger prior to supplying it to the fluid dynamic pump. Such a heat exchanger may use a phase change material.

In another preferred embodiment of the subject invention, the thermal management system may use HTF in a substantially gaseous form supplied by a supply tank at high pressure. HTF temperature may be changed in a suitable secondary heat exchanger, or in a vortex tube, or in a turboexpander prior to supplying it to the fluid dynamic pump.

In yet another preferred embodiment of the subject invention, the thermal management system may use HTF in a substantially liquid form supplied at high pressure by a pump. HTF temperature may be changed in a suitable secondary heat exchanger prior to supplying it to the fluid dynamic pump.

In yet further preferred embodiment of the subject invention, the thermal management system evaporate at least a portion of HTF passing though the HEX. Resulting HTF in a substantially vapor form is separated from HTF in a substantially liquid form and released. Separated HTF in a substantially liquid form is then recirculated by the fluid dynamic pump back into the HEX.

These and other features and advantages of the invention will be more fully understood from the following description of certain specific embodiments of the invention taken together with the accompanying drawings.

Accordingly, it is an object of the present invention to provide a lightweight and compact thermal management system.

It is another object of the invention to provide a thermal management system for reduced HTF inventory.

It is yet another object of the invention to provide a thermal management system conducive to reduced energy consumption.

It is still another object of the invention to provide a thermal management system conducive to fast startup.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic view of a thermal management system according one embodiment of the present invention.

FIG. 2 is a diagrammatic view of a thermal management system according alternative embodiment of the present invention suitable for liquid HTF.

FIG. 3 is a diagrammatic view of a thermal management system according another embodiment of the present invention suitable for gaseous HTF.

FIG. 4 is a diagrammatic view of a thermal management system according yet another embodiment of the present invention suitable for continuous operation.

FIG. 5 is a diagrammatic view of a thermal management system according still another embodiment of the present invention suitable for use with evaporative HTF.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Selected embodiments of the present invention will now be explained with reference to drawings. It will be apparent to those skilled in the art from this disclosure that the following descriptions of the embodiments of the present invention are merely exemplary in nature and are in no way intended to limit the invention, its application, or uses.

Referring to FIG. 1 of the drawings in detail, numeral 10 generally indicates a thermal management system (TMS) generally comprising a fluid-dynamic pump 120, heat exchanger (HEX) 182, back-pressure valve 152, return pipe 136, and interconnecting pipes 132 and 138. The HEX 182 may be in good thermal communication with a body 190 that requires thermal management. Alternatively, the HEX may be adapted to exchange heat between two separate HTFs. The HEX 182 may have an inlet port 154 and an outlet port 156. The fluid dynamic pump 120, HEX 182, return pipe 136, and interconnecting pipes 132 and 138 form a recirculation loop 124. In general, the fluid-dynamic pump 120 is arranged to feed a suitable HTF to the inlet port 154 of the HEX 182 and to recirculate a portion of HTF flowing from the outlet port 156 back to the inlet port of the HEX. The fluid-dynamic pump 120 may further comprise a driving nozzle 140 and a pump body 134. The pump body 134 is generally configured as a duct including a suction chamber 128. The pump body may also include a converging portion, which may be followed by followed by a straight portion, which may be followed by a diverging portion. The suction chamber 128 includes a suction port 162. The downstream portion of the pump body 134 has a discharge port 164. The suction port 162 of fluid dynamic pump 120 is fluidly connected to the return pipe 136. The discharge port 164 of fluid dynamic pump 120 is fluidly connected to the inlet port 154 of heat exchanger 182 by means of the pipe 132. The back pressure valve 152 is fluidly connected to the outlet port 156 of heat exchanger 182 by means of pipe 138. The return pipe 136 is also fluidly connected to the outlet port 156 of heat exchanger 182 by means of the pipe 138. The driving nozzle 140 is of fluid-dynamic pump 120 arranged to discharge high-velocity flow (jet) 142 into the throat of the pump body 134. This arrangement is common in fluid dynamic pumps. The driving nozzle 140 is fluidly connected by means of a supply line 148 to a source of high-pressure HTF. The back pressure valve 152 is arranged to provide a flow impedance to HTF flowing therethrough. One advantage of the back pressure valve 152 is its adjustability. In variant of the invention not requiring adjustability, alternative flow-impeding device such as an orifice or a venture may be used.

If the heat transfer fluid is gas, the fluid dynamic pump may be an ejector. Suitable ejectors with a single driving nozzle are Series 20A ejectors made by Penberthy, Prophetstown, Pa. Alternative ejectors may have multiple driving nozzles and/or lobed driving nozzles. If the heat transfer fluid is liquid, the fluid dynamic pump may be a hydraulic ejector also known as a jet pump. Suitable hydraulic ejectors with a single driving nozzle are Series 60A ejectors made by Penberthy, Prophetstown, Pa. Alternative hydraulic ejectors may have multiple driving nozzles and/or lobed driving nozzles. If the heat transfer fluid is liquid, the tank 160 may include a bladder (also known as diaphragm or membrane) which separates the heat transfer fluid from pressurizing gas (pressurant).

In operation, the fluid dynamic pump 120, HEX 182, return pipe 136, and interconnecting pipes 132 and 138 are substantially filled with suitable HTF. High-pressure HTF is supplied by a stream 175 via the supply line 148 to the driving nozzle 140 where it forms a jet 142 that is directed into the throat portion of the pump body 134. The jet 142 entrains HTF in the suction chamber 128 and pumps it. Stream 176 containing both the jet flow and the pumped HTF exists the fluid dynamic pump 120 through the discharge port 164 and flows through the pipe 132 into the inlet port 154 of HEX 182. The HTF exchanges heat inside the HEX 182 and exists the HEX 182 through the outlet port 156 as a stream 176′ flowing in the pipe 138. A portion of the HTF stream 176′ is separated and directed as a recirculating stream 172 into the return pipe 136. The unseparated portion of the stream 176′ forms an exit stream 174 that is released the thermal management system 10 through he back pressure valve 152. The back pressure valve 152 may be adjusted so that a large portion of the stream 176′ is directed in the form of the recirculating stream 172 into the return pipe 136. As a result, a large flow may be maintained through the HEX 182 while the overall consumption of fresh HTF as, for example, measured by the flow in the stream 175 fed to the driving nozzle 140 is substantially smaller. HTF supplied to the nozzle 140 may be provided at a temperature such that the stream 176 (which is a mixture of nozzle flow and the stream 172) fed to the HEX 182 is provided at a predetermined temperature value. In particular, if the HTF is gas and a cooling action is desired in the HEX 182, the gas provided in the line 148 may be chilled in a heat exchanger, a vortex tube, or a turboexpande prior to being fed to nozzle 140. Temperature of HTD leaving the HEX 182 may be also controlled by appropriately adjusting the backpressure valve 152. An alternative method for controlling the temperature of HTD leaving the HEX 182 may be achieved by appropriately adjusting the pressure of HTF supplied to the nozzle 140.

Referring now to FIG. 2, there is shown a thermal management system 11 in accordance with alternative embodiment of the invention which is particularly suitable for use with liquid HTF. The TMS 11 is generally the same as the TMS 10, except that it further comprises a supply tank 160 and receiving tank 192. The supply tank 160 is fluidly connected to the driving nozzle 140 and adapted for supplying high pressure HTF 168 to it. The supply tank 160 may also include a diaphragm 170. The space 158 above the diaphragm may be provided with gas at high pressure (pressurant) that may be provided by a supply line 116. A control valve 112 may be provided to control the flow of HTF from the tank 160 to the nozzle 140. A secondary heat exchanger 180 may be provided to either heat or cool the high pressure HTF prior to delivery to the driving nozzle 140. The secondary heat exchanger 180 may include a phase change material. The a receiving tank 192 is adapted for collecting HTF in stream 174, which is the portion of HTF not recirculated back into HEX 182. The receiving tank 192 may also include a diaphragm 166. The space 158′ above the diaphragm may be provided with gas at pressure (pressurant) that may be provided by a supply line 114. Pressurant in the space 158′ of the receiving tank 192 should be at a substantially lower pressure than gas in the space 158 of the supply tank 160. In some variants of this embodiment, the backpressure valve 152 may be omitted and the back pressure in HTF stream 174 maintained by the pressure of gas in space 158 of the receiving tank 192.

In operation, pressure of pressurant in the supply tank is set substantially higher than the pressure of pressurant in the receiving tank, and the control valve 112 is set open. Fresh HTF flows from the supply tank 160 to the driving nozzle 140 and “expended” HTF flows in stream 174 to the receiving tank. When the supply tank 160 becomes empty, means may be provided to transfer the HTF from the receiving tank 192 into the tank 160. Such means may include a pump and appropriate plumbing.

Referring now to FIG. 3, there is shown a thermal management system 12 in accordance with another embodiment of the invention which is particularly suitable for use with gaseous HTF. The TMS 12 is generally the same as the TMS 11, except that the supply tank 160′ may not include a diaphragm and the receiving tank may be omitted. In addition, the driving nozzle 140′ is preferably a supersonic nozzle. A secondary heat exchanger 180 may be provided to either heat or cool the high pressure HTF prior to delivery to the driving nozzle 140. Alternatively, a cooling or heating action may be provided by flowing HTF through a vortex tube prior to feeding it to the nozzle 140′. As a yet another alternative, a cooling action may be provided by flowing HTF through a turboexpander prior to feeding it to the nozzle 140′.

FIG. 4 shows a thermal management system 13 in accordance with yet another embodiment of the invention which is particularly suitable for continuous operation using liquid HTF. The TMS 13 is generally the same as the TMS 10, except that it further comprises a pump which receives the HTF stream 174 after it has passed through the backpressure valve 152, and feed HTF at high pressure to the secondary heat exchanger 180, and therethrough to the driving nozzle 140 of the fluid dynamic pump 120. If the HEX 180 is arranged to deposit heat into HTF flowing therethrough, then the secondary heat exchanger 180 may be arranged to remove heat from HTF flowing therethrough. Conversely, if the HEX 180 is arranged to remove heat from HTF flowing therethrough, then the secondary heat exchanger 180 may be arranged to deposit heat to HTF flowing therethrough.

FIG. 5 shows a thermal management system 14 in accordance with still another embodiment of the invention which is particularly suitable for operation using evaporative HTF. The TMS 14 is generally the same as the TMS 10, except that it further includes a gas-liquid separator 199. The gas-liquid separator 199 has an inlet port, a gas outlet port, and a liquid outlet port. The suction port 162 of the fluid dynamic pump 120 is fluidly connected via the return pipe 136 to the liquid output port of the gas-liquid separator 199. The outlet port 156 of the HEX 182 is fluidly connected via the pipe 138 to the inlet port of the gas-liquid separator 199. The gas outlet port of the gas-liquid separator 199 is fluidly connected to the backpressure valve 152 via the line 189.

In operation, suitable HTF in a substantially liquid form is supplied under high pressure via the supply line 148 to the motive nozzle 140 of the fluid dynamic pump 120 where it forms a jet 142 which is directed into the throat portion of the pump body 1834. The jet 142 entrains HTF in the suction chamber 128 and pumps it. HTF stream 176 containing both the jet flow and the pumped HTF from the pipe 136 exists the fluid dynamic pump 120 through the discharge port 164 and flows through the pipe 132 into the inlet port 154 of the HEX 182. The HTF receives heat from the HEX 182, which may cause a portion of the HTF to evaporate. The HTF exists the HEX 182 as a stream 176″ (which may be a mixture of liquid and vapor, e.g., in the form of bubbles) through the outlet port 156 and flows through the pipe 138 into the inlet port of the gas-liquid separator 199. The gas-liquid separator 199 separates the incoming HTF mixture of liquid and vapor into a portion of that is substantially in a liquid state and a portion that is substantially in a vapor (gaseous) state. The portion of HTF in a substantially liquid state is fed as a stream 172 through the liquid output port of the gas-liquid separator 199 into the return pipe 136, and therethrough into the suction chamber 128 of the fluid dynamic pump 120, where it may be pumped by the jet 142. The portion of HTF in a substantially vapor (gaseous) state is fed as a stream 174 through the gas output port of the gas-liquid separator 199 into the pipe 189. The pipe 189 carries the stream 174 through the backpressure valve 128 that may release it from the thermal management system 14. In some variants of the invention, the backpressure valve releases the stream 174 into the atmosphere. In some other variants of the invention, the backpressure valve releases the stream 174 into a compressor. Such a compressor may be a part of a vapor-compression refrigeration system that may liquefy the HTF vapor, chill it, and feed it as a stream 175 into the driving nozzle 140.

The backpressure valve 152 may be adjusted so that a desired pressure can be attained in the recirculation loop 124′. The pressure in the recirculation loop 124′ influences the amount of flow in the stream 172. Preferably, the backpressure valve 152 is adjusted so that the stream 172 contains the HTF mostly in a liquid form. In some variants of the invention, the backpressure valve 152 may be replaced by a suitable flow-impeding element such as an orifice or a venturi. In some other variants of the invention, the backpressure valve 152 may be an expansion valve. In yet other alternative versions of the invention, a flow impeding device (such as valve, orifice, venture, or like) may be installed in the pipe 138. Such a flow impeding device may suppress (at least in-part) evaporation (boiling) of the heat transfer fluid in the HEX 182, which may be desirable in some applications of the invention. Evaporation may then occur downstream of the flow impeding device. By appropriately setting the backpressure valve 152, a large mass flow may be maintained through the HEX 182 while the overall consumption of the HTF as, for example, measured by the HTF mass flow through the driving nozzle 140 may be substantially smaller. The selection of HTF for practicing with the thermal management system 14 may include water, alcohol, refrigerants (e.g., Freons and ammonia), and cryogenic liquids (e.g., liquid nitrogen, liquid helium, liquid carbon dioxide, liquid natural gas, and liquid propane).

Uses of the subject invention include cooling of devices requiring heat transfer at very high heat flux including photovoltaic cells used with a concentrator, thermal photovoltaic cells, semiconductor laser diodes, semiconductor electronics, and laser gain medium. Other uses of the invention include removing heat from solar panels. Further uses of the invention include systems for refrigeration, air conditioning, and gas liquefaction.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” and “includes” and/or “including” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

HTF suitable for use with the subject invention include 1) liquids such as water, aqueous solution of alcohol, antifreeze, and oil, 2) gases including air, helium, natural gas, and nitrogen, and 3) vapors such water steam, Freon, and ammonia.

The terms of degree such as “substantially”, “about” and “approximately” as used herein mean a reasonable amount of deviation of the modified term such that the end result is not significantly changed. For example, these terms can be construed as including a deviation of at least ±5% of the modified term if this deviation would not negate the meaning of the word it modifies.

Moreover, terms that are expressed as “means-plus function” in the claims should include any structure that can be utilized to carry out the function of that part of the present invention. In addition, the term “configured” as used herein to describe a component, section or part of a device includes hardware and/or software that is constructed and/or programmed to carry out the desired function.

While only selected embodiments have been chosen to illustrate the present invention, it will be apparent to those skilled in the art from this disclosure that various changes and modifications can be made herein without departing from the scope of the present invention as defined in the appended claims. Furthermore, the foregoing description of the embodiments according to the present invention are provided for illustration only, and not for the purpose of limiting the present invention as defined by the appended claims and their equivalents. Thus, the scope of the present invention is not limited to the disclosed embodiments.

Claims

1. A thermal management system comprising:

(a) a heat exchanger having an inlet for receiving heat transfer fluid and outlet for discharging heat transfer fluid; and

(b) a fluid dynamic pump having a driving nozzle fluidly connected to a source of heat transfer fluid, a suction port fluidly connected to said outlet port of said heat exchanger, and a discharge port fluidly connected to said inlet port of said heat exchanger.

2. The thermal management system of claim 1 further comprising a means for releasing excess heat transfer fluid, said means fluidly connected to said outlet of said heat exchanger.

3. The thermal management system of claim 2 wherein said means to remove excess heat transfer fluid include a flow-impeding element.

4. The thermal management system of claim 2 wherein said flow-impeding element is selected from the group consisting of a backpressure valve, an orifice, and a venturi.

5. The thermal management system of claim 1 wherein said heat exchanger is adapted for exchanging heat between said heat transfer fluid and a body.

6. The thermal management system of claim 1 wherein said heat exchanger is adapted for exchanging heat between said heat transfer fluid and a second heat transfer fluid.

7. The thermal management system of claim 1 wherein said heat transfer fluid is fed to said driving nozzle in a substantially liquid form.

8. The thermal management system of claim 1 wherein said heat transfer fluid is fed to said driving nozzle in a substantially gaseous form.

9. A thermal management system comprising a heat exchanger (HEX), a fluid dynamic pump, and a flow-impeding element;

(a) said HEX having and inlet port and an outlet port;

(b) said fluid dynamic pump having a driving nozzle, suction port, and a discharge port;

(c) said driving nozzle being fluidly connected to a supply of heat transfer fluid (HTF);

(d) said discharge port being fluidly connected to said inlet port of said HEX;

(e) said suction port of said fluid dynamic pump being fluidly connected to said outlet port of said HEX; and

(f) said flow-impeding element being fluidly connected to said outlet port of said HEX and adapted for releasing excess HTF.

10. The thermal management system of claim 9 wherein said flow-impeding element is selected from the group consisting of a backpressure valve, an orifice, and a venturi.

11. The thermal management system of claim 9 wherein said HEX is adapted to exchanging heat between said HTF and a body.

12. The thermal management system of claim 9 wherein said HEX is adapted to exchanging heat between said HTF and a second heat HTF.

13. The thermal management system of claim 9 wherein said HEX is provided to said driving nozzle in a substantially liquid form.

14. The thermal management system of claim 9 wherein said HTF is provided to said driving nozzle in a substantially gaseous form and said driving nozzle of said fluid dynamic pump is a supersonic nozzle.

15. The thermal management system of claim 9 wherein said HEX is arranged to exchange heat between said HTF and a body selected from the group consisting of photovoltaic cell, thermal photovoltaic cell, solar panel, semiconductor laser diode, semiconductor electronic component, and a laser gain medium.

16. A system for providing heat transfer fluid (HTF) to a heat exchanger (HEX), said system comprising:

a supply tank adapted for supplying HTF under pressure;

a HEX having an inlet for receiving HTF and outlet for discharging HTF; and

a fluid dynamic pump having a driving nozzle fluidly connected to said supply tank and adapted to receive HTF therefrom, a suction port fluidly connected to said outlet port of said heat exchanger, and a discharge port fluidly connected to said inlet port of said HEX.

17. The thermal management system of claim 16 further comprising a means for releasing excess HTF through a flow-impeding element (FIE), said means fluidly connected to said outlet of said HEX.

18. The thermal management system of claim 16 further comprising a means for chilling said HTF provided by said supply tank before it is fed to said driving nozzle.

19. The thermal management system of claim 17 wherein said means for chilling said HTF is selected from the group consisting of a vortex tube, turboexpander, a second heat exchanger, and phase change material.

20. The thermal management system of claim 16 further comprising a receiving tank fluidly connected to said outlet of said HEX and adapted for receiving excess HTF therefrom.

21. The thermal management system of claim 20 wherein said released HTF is flowing to said receiving tank through a flow-impeding element.

22. A system for providing heat transfer fluid (HTF) to a heat exchanger (HEX), said system comprising:

a pump adapted for supplying HTF under pressure;

a HEX having an inlet for receiving HTF and outlet for discharging HTF, said outlet being fluidly connected to the suction port of said pump; and

a fluid dynamic pump having a driving nozzle fluidly connected to said pump and arranged for receiving HTF therefrom, a suction port fluidly connected to said outlet port of said heat exchanger, and a discharge port fluidly connected to said inlet port of said heat exchanger.

23. The thermal management system of claim 22 further comprising a flow-impeding element installed in said fluid connection between said HEX outlet and said suction port of said pump; said flow-impeding element arranged to maintain the HTF pressure at said HEX outlet higher than the HTF pressure at said suction port of said pump.

24. The thermal management system of claim 22 further comprising a secondary heat exchanger installed between said pump and said driving nozzle, said secondary heat exchanger adapted for exchanging heat with the HTF prior to supplying to said driving nozzle.

25. A system for recirculation of heat transfer fluid through a heat exchanger, said system comprising:

(a) a source of heat transfer fluid arranged to provide heat transfer fluid under pressure;

(b) a heat exchanger having an inlet for receiving heat transfer fluid and outlet for discharging heat transfer fluid;

(c) a fluid dynamic pump having a driving nozzle fluidly connected to said source of heat transfer fluid, a suction port fluidly connected to said outlet port of said heat exchanger, and a discharge port fluidly connected to said inlet port of said heat exchanger; and

(d) a means for releasing a portion of heat transfer fluid from said outlet of said heat exchanger, said means arranged to maintain a predetermined back pressure at said outlet of said heat exchanger.

26. A method for supplying heat transfer fluid to a heat exchanger comprising the acts of:

(a) presenting a source of heat transfer fluid;

(b) presenting a heat exchanger having an inlet for receiving heat transfer fluid and outlet for discharging heat transfer fluid;

(c) presenting a fluid dynamic pump having a driving nozzle fluidly connected to said source of heat transfer fluid, a suction port fluidly connected to said outlet port of said heat exchanger, and a discharge port fluidly connected to said inlet port of said heat exchanger;

(d) presenting a means for releasing heat transfer fluid from said outlet of said heat exchanger;

(e) feeding heat transfer fluid under pressure into said driving nozzle to produce a pumping action in said fluid dynamic pump;

(f) admitting heat transfer fluid into said suction port;

(g) pumping said heat transfer fluid with said fluid dynamic pump;

(h) feeding heat transfer fluid from said discharge port to said inlet port of said heat exchanger;

(i) exchanging heat between said heat transfer fluid and said heat exchanger;

(j) flowing said heat transfer fluid from said heat exchanger through said outlet port; and

(k) feeding a portion of said heat transfer fluid flowing from said heat exchanger through said outlet port into said suction port of said fluid dynamic pump.

27. The method of claim 26 further including the act of releasing excess heat transfer fluid through a flow impeding device.

28. The method of claim 26 further including the act of controlling the temperature of said heat transfer fluid flowing from said heat exchanger through said outlet port by adjusting the pressure of said heat transfer fluid at said outlet of said heat exchanger.

29. The method of claim 26 further including the act of controlling the temperature of said heat transfer fluid flowing from said heat exchanger through said outlet port by adjusting the pressure of said heat transfer fluid fed to said driving nozzle.

30. The method of claim 26 further including the act of controlling the temperature of said heat transfer fluid flowing from said heat exchanger through said outlet port by adjusting the temperature of said heat transfer fluid fed to said driving nozzle.

31. A method for supplying heat transfer fluid to a heat exchanger comprising the acts of:

(a) presenting a source of heat transfer fluid;

(b) presenting a heat exchanger having an inlet for receiving heat transfer fluid and outlet for discharging heat transfer fluid;

(c) presenting a fluid dynamic pump having a driving nozzle fluidly connected to said source of heat transfer fluid, a suction port fluidly connected to said outlet port of said heat exchanger, and a discharge port fluidly connected to said inlet port of said heat exchanger;

(d) presenting a means for releasing heat transfer fluid from said outlet of said heat exchanger;

(e) feeding heat transfer fluid under pressure into said driving nozzle to produce a pumping action in said fluid dynamic pump;

(f) admitting heat transfer fluid into said suction port;

(g) pumping said heat transfer fluid with said fluid dynamic pump;

(h) feeding heat transfer fluid from said discharge port to said inlet port of said heat exchanger;

(i) exchanging heat between said heat transfer fluid and said heat exchanger;

(j) evaporating a portion of said heat transfer fluid;

(k) flowing a mixture of liquid and vapor of said heat transfer fluid from said heat exchanger through said outlet port;

(l) separating said mixture of liquid and vapor of said heat transfer fluid into a portion containing substantially liquid and another portion containing substantially vapor; and

(m) feeding said portion of said heat transfer fluid containing substantially liquid into said suction port of said fluid dynamic pump.