HYBRID THERMOELECTRIC-EJECTOR COOLING SYSTEM

• US 20110079022A1
• Filed: 10/01/2010
• Published: 04/07/2011
• Est. Priority Date: 10/01/2009
• Status: Active Grant

• Current Assignee: Curators of the University of Missouri (University of Missouri)
• Original Assignee: Hongbin Ma, Joseph A. Boswell, Peng Cheng
• Inventors: Ma, Hongbin, Boswell, Joseph A., Cheng, Peng
• Granted Patent: US 8,763,408 B2
• Time in Patent Office: Days
• US Class Current: 62/3.2
• CPC Class Codes: F25B 21/02 using Peltier effect; using Nernst-Ettinghausen effect
• CPC Class Codes: F28D 15/043 forming loops, e.g. capillary pumped loops

Abstract

A hybrid thermoelectric-ejector active cooling system having an increased Coefficient of Performance (COP) when compared to typical thermoelectric cooling modules. A thermoelectric cooling module is integrated with an ejector cooling device so that heat from the thermoelectric cooling module is rejected to a high temperature evaporator of the ejector cooling device. This provides for a total COP greater than the sum of the COPs of the thermoelectric cooling module and ejector cooling device individually. For example, given 1 unit input power into the thermoelectric cooling module, the heat received by the cold side of the thermoelectric cooling module would be COP_TEC×1; and the energy rejected by the hot side of the thermoelectric cooling module and to drive the ejector cooling device would be COP_TEC+1. Thus, the cooling received by the low temperature evaporator of the ejector cooling device is COP_EJ×(COP_TEC+1); and therefore total COP_TE-Ej-AC is COP_Ej+COP_TEC+COP_Ej×COP_TEC. In addition, the hybrid thermoelectric ejector active cooling system will be able to operate at higher temperature differentials than standalone thermoelectric cooling devices.

Claims

1. An active cooling system for transferring heat from a heat source to an external heat sink comprising an ejector cooling system having a high temperature evaporator and a low temperature evaporator, and a thermoelectric cooling device having a hot side in thermal communication with the high temperature evaporator for supplying heat used to vaporize a primary fluid and a cold side in thermal communication with the low temperature evaporator for removing heat from the low temperature evaporator.

2. An active cooling system as set forth in claim 1 wherein the ejector comprises a nozzle and a mixing chamber, the mixing chamber being in fluid communication with the low temperature evaporator, the nozzle being in fluid communication with the high temperature evaporator and the mixing chamber for ejecting primary fluid from the high temperature evaporator to aspirate secondary fluid vapor into the mixing chamber.

3. An active cooling system as set forth in claim 2 further comprising a condenser downstream of the ejector and in fluid communication with the mixing chamber for receiving and condensing primary and secondary fluid from the mixing chamber.

4. An active cooling system as set forth in claim 3 further comprising wicking structure in the condenser and in the high temperature evaporator constructed to move primary fluid in liquid from the condenser at lower pressure to the high temperature evaporator at a higher temperature.

5. An active cooling system as set forth in claim 4 further comprising wicking structure interconnecting the high temperature evaporator to the low temperature evaporator and constructed to resist flow of primary fluid into the low temperature evaporator so as to avoid starving the high temperature evaporator of primary fluid.

6. An active cooling system as set forth in claim 5 wherein the thermoelectric cooling device comprises a plate including the hot side and the cold side, the plate being adapted to have an electric potential.

7. An active cooling system as set forth in claim 6 wherein the plate has an opening, the fluid communication of the low temperature evaporator with the ejector occurring through the opening in the plate.

8. An active cooling system as set forth in claim 7 wherein the plate has return openings placing the high temperature evaporator in fluid communication with the low temperature evaporator.

9. An active cooling system as set forth in claim 8 wherein the low temperature evaporator includes a thin film evaporation surface to promote evaporative cooling in the low temperature evaporator.

10. An active cooling system for transferring heat from a heat source to an external heat sink comprising a low temperature evaporator for removing heat from the heat source, a pump for drawing refrigerating fluid from the low temperature evaporator and increasing the pressure of the fluid, a condenser downstream of the pump for use in condensing the refrigerating fluid, a wicking structure in the condenser and extending generally to the low temperature evaporator for capturing at least a portion of the condensed refrigerating fluid in the condenser and moving the condensed refrigerating fluid by capillary action back to the low temperature evaporator.

11. An active cooling system as set forth in claim 10 wherein the pump comprises an ejector that aspirates secondary fluid in the low temperature evaporator and increases the pressure of the secondary fluid for condensing.

12. An active cooling system as set forth in claim 10 wherein the wicking structure is configured according to the physical characteristics of the fluid to maximize capillary action.

13. An active cooling system as set forth in claim 12 wherein the wicking structure is constructed to resist backwards flow of higher pressure vapor into the condenser.

14. An active cooling system as set forth in claim 10 further comprising a high temperature evaporator between the low temperature evaporator and the condenser, and wherein the wicking structure is configured to provide flow resistance to condensed fluid passing from the high temperature evaporator to the low temperature evaporator to maintain liquid quantities in the high temperature evaporator.

15. An active cooling system for transferring heat from a heat source to an external heat sink comprising:

a. a low temperature evaporator adapted to receive a secondary fluid for evaporation of the secondary fluid to absorb heat from the heat source;

b. a thermoelectric cooling module which uses electrical input power to generate heat flux;

c. an ejector cooling module integrated with the thermoelectric module, the ejector cooling module including a high temperature evaporator adapted to container a primary fluid, the thermoelectric cooling module being disposed for rejecting heat into the high temperature evaporator of the ejector cooling module, a converging-diverging nozzle connected to the high temperature evaporator for accelerating primary fluid to a high velocity and producing low static pressure, a mixing chamber for receiving high velocity primary fluid from the converging-diverging nozzle and aspirating secondary fluid vapor from the low temperature evaporator, a diffuser chamber for receiving mixed primary and secondary fluid vapor from the mixing chamber, the diffuser chamber being adapted to transition the flow of mixed primary and secondary fluids from high speed to stagnation so that the mixed flow can gain static pressure;

d. a condenser adapted to receive the primary and secondary fluid vapor from the ejector'"'"'s diffuser chamber and reject heat to a heat sink outside the cooling system so that the vaporous primary and secondary fluids lower their temperature to their saturation points and liquefy;

e. a wick structure connecting the condenser to the high temperature evaporator so that the liquids in the condenser can travel from the condenser to the high temperature evaporator by way of capillary force;

f. a micro/nano-structured surface within the high temperature evaporator to distribute the liquid within the high temperature evaporator and to enhance thin film evaporation heat transfer;

g. a duct between the high temperature evaporator and the low temperature evaporator constructed to pass fluid from the high temperature to the low temperature evaporator at a certain flow rate of liquid to provide sufficient flow to the low temperature evaporator but not so much flow that the high temperature evaporator lacks sufficient fluid for heat transfer from the thermoelectric cooling module or for powering the ejector;

h. a micro/nano-structured surface within the low temperature evaporator to distribute the liquid within the low temperature evaporator and to enhance thin film evaporation heat transfer;

i. insulating material located between at least one of,

i. the condenser and high temperature evaporator; and

ii. the ejector'"'"'s diffuser and high temperature evaporator