HEAT EXCHANGER ASSEMBLY FOR AN AIRCRAFT CONTROL
A heat exchanger assembly for an aircraft control has an aircraft control for controlling an operation of an aircraft. The aircraft control is in thermal communication with a first fluid. A first thermoelectric device is configured to transfer heat between the first fluid and the second fluid against a temperature gradient of the first fluid and the second fluid. A temperature sensor is provided for sensing a temperature of the first fluid. A temperature control is also configured to control the first thermoelectric device based on an input from the temperature sensor.
This invention relates to a heat exchanger for an aircraft control. An aircraft has a number of electronic controls used to control an operation of the aircraft. One such control manages the function of the aircraft engines and is commonly known as a Full Authority Digital Engine Control or FADEC. The FADEC is generally installed in an environment of the aircraft susceptible to both very high temperatures and very low temperatures. For example, the FADEC may be installed in the engine bay where large amounts of heat are generated during flight conditions. In these conditions, the FADEC requires a substantial amount of cooling to limit its operating temperature. When the aircraft is not in flight, however, the engine bay may be extremely cold when ambient air temperature is low. At these conditions, the FADEC requires very little, if any, cooling.
The FADEC, like many aircraft controls, is composed of electronic components that require moderate and uniform temperatures for optimal operation. The large temperature swings experienced by the FADEC is not conducive to the best performance of these temperature sensitive components. While there are electronic components that are capable of performing at the extreme temperature conditions of the aircraft, these components are generally very expensive and have relatively low performance (memory, process, or speed) compared to most modern electronics.
A need therefore exists for an assembly and technique that maintains the electronics of an aircraft control within their designed operating temperatures.
SUMMARY OF THE INVENTIONA heat exchanger assembly includes an aircraft control. The aircraft control is in thermal communication with a first fluid. A first thermoelectric device is configured to transfer heat between the first fluid and a second fluid against a temperature gradient of the first fluid and the second fluid. A temperature sensor is provided for sensing a temperature of the first fluid. A temperature control is also configured to control the first thermoelectric device based on an input from the temperature sensor.
The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the currently preferred embodiment. The drawings that accompany the detailed description can be briefly described as follows:
In
Frame 19 has first fluid 18 to act as a heat exchanger for printed circuit boards 12 through heat sinks 15 and heat conduction posts 17. In this regard, first fluid 18 may be any of a variety of fluids, including aircraft engine fuel, ethylene glycol or any antifreeze. Frame 19 has fluid channel 21, an internal conduit that allows the circulation of first fluid 18 via pump 115 to thermoelectric assembly 108 and back to frame 19. First fluid 18 is contained in a closed fluid loop, here closed first loop 102.
At thermoelectric assembly 108, first fluid 18 exchanges heat with second fluid 34. Second fluid 34 is contained in another closed loop, second closed loop 103, which includes, by way of example, aircraft fuel reservoir 36, pump 117, and thermoelectric assembly 108. Pump 117 pumps second fluid 34, here aircraft engine fuel, through thermoelectric assembly 108 back to fuel reservoir 36.
The exchange of heat between first fluid 18 and second fluid 34 occurs through thermoelectric assembly 108. Normally, second fluid 34 is at a higher temperature than first fluid 18. Hence, transferring heat from first fluid 18, which is at a lower temperature than second fluid 34, is against the temperature gradient between the two fluids and generally would not occur. Thermoelectric assembly 108 is provided to thereby allow first fluid 18 to transfer heat to second fluid 34 against the temperature gradient of the two fluids.
Thermoelectric assembly 108 has first thermoelectric device 22, second thermoelectric device 70 and third thermoelectric device 82. As shown in
First thermally conductive plate 94 and second thermally conductive plate 98, here made of aluminum, sandwich and encase substrate 24 so as to prevent fluid from damaging thermoelectric elements 111. Because first thermally conductive plate 94 and second thermally conductive plate 98 are both made of metal, they further provide a highly thermally conductive surface for the transmission of heat in the direction of arrow R or in the direction of arrow S. Hence, heat may be transferred between two fluids, such as first fluid 18 and second fluid 34, against the temperature gradient between the two fluids by controlling the electric current through thermoelectric elements 111.
The operation of heat exchanger assembly 10 will now be explained with reference to
With reference to first thermoelectric device 22 shown in
As shown in
A close up view of first plurality of flow conducts 46, first thermoelectric device 22 and second plurality of flow conduits 50 is shown in
As shown
There may be times when the temperature of first fluid 18 is too low, such as when the aircraft is inactive and ambient temperature is cold. In such an instance, first fluid 18 may, in fact, be at a lower temperature than second fluid 34. Then, temperature control 30 may reverse current to first thermoelectric device 22, second thermoelectric device 70 and third thermoelectric device 82 so that they transfer heat in the opposite direction, from second fluid 34 to first fluid 18. Temperature of first fluid 18 can be moderated in this fashion.
In
The aforementioned description is exemplary rather that limiting. Many modifications and variations of the present invention are possible in light of the above teachings. The preferred embodiments of this invention have been disclosed. However, one of ordinary skill in the art would recognize that certain modifications would come within the scope of this invention. Hence, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described. For this reason the following claims should be studied to determine the true scope and content of this invention.
Claims
1. A heat exchanger assembly for an aircraft control, comprising:
- an aircraft control for controlling an operation of an aircraft;
- said aircraft control in thermal communication with a first fluid;
- a first thermoelectric device configured to transfer heat between said first fluid and a second fluid against a temperature gradient of said first fluid and said second fluid;
- a temperature sensor for sensing a temperature of said first fluid; and
- a temperature control configured to control said first thermoelectric device based on an input from said temperature sensor.
2. The assembly of claim 1 wherein said second fluid is an aircraft engine fuel.
3. The assembly of claim 1 wherein said first thermoelectric device has a first side and a second side, said first fluid in thermal communication with said first side and said second fluid in thermal communication with said second side.
4. The assembly of claim 3 including a first plurality of flow conduits and a second plurality of flow conduits, said first plurality of flow conduits for guiding said first fluid across said first side of said first thermoelectric device and said second plurality of flow conduits for guiding said second fluid across said second side of said first thermoelectric device.
5. The assembly of claim 4 wherein said first fluid is configured to flow along said first side in a first direction and said second fluid is configured to flow along said second side in a second direction, said first direction different than said second direction.
6. The assembly of claim 5 wherein said first direction is generally opposite said second direction.
7. The assembly of claim 5 wherein said first direction is transverse to said second direction.
8. The assembly of claim 3 including a second thermoelectric device, said second thermoelectric device spaced from said first thermoelectric device and having a third side and fourth side, said third side facing said second side of said first thermoelectric device, said second fluid disposed between said second side and said third side.
9. The assembly of claim 8 including a third thermoelectric device having a fifth side and a sixth side, said fifth side facing said fourth side of said second thermoelectric device wherein said second thermoelectric device is sandwiched between said first thermoelectric device and said third thermoelectric device.
10. The assembly of claim 9 wherein said first fluid is on said first side, said second fluid disposed on said second side between said second side and said third side, said first fluid is also disposed between said fourth side and said fifth side, and said second fluid is also disposed on said sixth side.
11. The assembly of claim 1 wherein said first thermoelectric device is configured to cool said first fluid when said second fluid has a higher temperature than said first fluid.
12. The assembly of claim 1 including a first thermally conductive plate and a second thermally conductive plate, said first thermoelectric device sandwiched by said first thermally conductive plate and said second thermally conductive plate, said first thermally conductive plate and said second thermally conductive plate sealing said first thermoelectric device against fluid.
13. The assembly of claim 1 wherein said first fluid is disposed in a closed loop.
14. A heat exchanger assembly for an aircraft control, comprising:
- an aircraft control for an aircraft;
- said aircraft control in thermal communication with a first fluid, said first fluid configured to cool said control;
- a first thermoelectric device configured to transfer heat from said first fluid to a second fluid having a higher temperature than said first fluid, said first thermoelectric device having a first side and a second side;
- a second thermoelectric device, said second thermoelectric device spaced from said first thermoelectric device and having a third side and fourth side, said third side facing said second side of said first thermoelectric device; and
- wherein said first fluid is on said first side, said second fluid between said second side and said third side, and said first fluid is also on said fourth side.
15. The assembly of claim 14 including a first plurality of flow conduits and a second plurality of flow conduits, said first plurality of flow conduits for guiding said first fluid across said first side of said first thermoelectric device and said second plurality of flow conduits for guiding said second fluid across said second side of said first thermoelectric device.
16. The assembly of claim 14 wherein said first fluid is configured to flow along said first side in a first direction and said second fluid is configured to flow along said second side in a second direction, said first direction different than said second direction.
17. The assembly of claim 14 wherein said first direction is generally opposite said second direction.
18. The assembly of claim 14 wherein said first direction is transverse to said second direction.
19. The assembly of claim 14 including a third thermoelectric device having a fifth side and a sixth side, said fifth side facing said fourth side of said second thermoelectric device wherein said second thermoelectric device is sandwiched between said first thermoelectric device and said third thermoelectric device wherein said first fluid is also disposed between said fourth side and said fifth side, and said second fluid is also disposed on said sixth side.
20. A method of controlling a temperature for an aircraft control, comprising the steps of:
- disposing a first fluid proximate a control for an aircraft, the first fluid configured to absorb heat from the control for the aircraft;
- providing a first flow path to a thermoelectric device;
- disposing a second fluid proximate the thermoelectric device, the second fluid configured to absorb heat from the first fluid through the thermoelectric device;
- providing a second flow path from the thermoelectric device to the control; and
- wherein the first thermoelectric device is configured to transfer heat from the first fluid to the second fluid when the first fluid has a higher temperature than the second fluid thereby cooling the first fluid.
Type: Application
Filed: Jul 21, 2008
Publication Date: Jan 21, 2010
Inventors: Charles E. Lents (Amston, CT), Trevor E. Bailey (Tolland, CT), Abbas A. Alahyari (Manchester, CT)
Application Number: 12/176,522
International Classification: F25B 21/02 (20060101);