Refrigeration – Using electrical or magnetic effect – Thermoelectric; e.g. – peltier effect
Reexamination Certificate
1999-10-27
2001-05-01
Doerrler, William (Department: 3744)
Refrigeration
Using electrical or magnetic effect
Thermoelectric; e.g., peltier effect
C062S003300
Reexamination Certificate
active
06223539
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to temperature control devices. More particularly, the present invention relates to a thermoelectric heat exchanger that is particularly useful for controlling the temperature of a seat, such as an automobile seat.
2. Description of the Related Art
Modern automobile seats may be equipped with temperature control systems that allow the occupant to vary the temperature of the seat by flowing temperature-controlled air through the seat covering. One type of system comprises a seat having a heat transfer system mounted therein, such as a thermoelectric element configured to heat or cool air that is moved over the element using a separate fan unit that is also mounted within the seat. The conditioned air is distributed to the occupant by passing the air through the seat surface via a series of air ducts within the seat.
The amount of space available within, below and around the seat for such temperature control systems is severely limited. In some cars, to save weight or increase passenger room, the seats are a few inches thick and abut the adjacent structure of the car, such as the floorboard or the back of the car. Further, automobile manufacturers are increasingly mounting various devices, such as electronic components or variable lumbar supports, within, below and around the seat. Additionally, the size of the seat, particularly the seat back, needs to be as small as possible to reduce the amount of cabin space consumed by the seat.
Present temperature control systems are often too large to be mounted within, below or around vehicle seats. Conventional systems may have a squirrel cage fan five or six inches in diameter generating an air flow that passes through a duct to reach a heat exchanger that adjusts the temperature of the air. The heat exchanger is several inches wide and long, and at least an inch or so thick. From the heat exchanger the air is transported through ducts to the bottom of the seat cushion and to the back of the seat cushion. Such systems are bulky and difficult to fit underneath or inside car seats. Using thermoelectric devices to heat and cool the heat exchanger helps reduce the size of unit, but still requires a large volume for the combined heating and cooling system.
The ducting used with these systems is also bulky and difficult to use if the duct must go from a seat bottom to a seat back that is allowed to pivot or rotate. These ducts not only use additional space within the seat, but also resist air flow and thus require a larger fan to provide the air flow, and the larger fan requires additional space or else runs at greater speeds and generates more noise. Noise is undesirable inside motor vehicles. Further, the ducting affects the temperature of the passing air and either heats cool air, or cools heated air, with the result of often requiring larger fans or heat exchangers.
In light of these drawbacks, there is a need for a more compact and energy efficient heating and cooling system for automobile seats, and preferably a quieter system.
SUMMARY OF THE INVENTION
This device uses air flow generators, such as fan blades, that act as both a heat exchanger to transfer a thermal differential from a thermoelectric device and thereby condition air passing over the heat exchanger, and that act as an air pump. The heat exchanger rotates and provides aerodynamic and centrifugal force to the air passing through the heat exchanger to generate pressurized air for distribution, such as to the seat of a motor vehicle.
In more detail, one embodiment of this device comprises at least one annular thermoelectric device (e.g., Peltier device) that, depending on the voltage applied, heats one surface and cools the opposing surface of the annular, thermoelectric device. Annular heat exchangers are placed in thermal communication with the opposing sides of the annular thermoelectric device by mounting them directly to the thermoelectric device so that each heat exchanger conducts the heat or cold from the surface of the device to which the heat exchanger is mounted. A resistive heating element may also be used to generate heat.
In one embodiment, the annular heat exchangers are formed with radial slots extending through the heat exchanger, and form an annular cavity inside the heat exchangers when assembled. A motor nests inside the annular cavity formed on the inside of the assembled annular heat exchangers and annular, thermoelectric device, but spaced apart from the heat exchangers and thermoelectric device by an amount sufficient to allow air to flow along the exterior of the motor. The motor is drivingly connected to one of the heat exchangers and thermoelectric device to rotate them. The rotating heat exchangers act as a fan, drawing air into the annular cavity and expelling the air through the radial slots of the heat exchangers at a higher pressure. The volume of compressed air created is determined by the motor size, the fan blade shape, the rotational speed, and the overall geometry of the assembly.
This arrangement allows the heat exchanger to be directly coupled to the thermoelectric device, and to act as a fan to not only generate the air pressure that distributes the conditioned air to passenger seats, but to condition the air as the air passes through the fan blades/heat exchanger. This reduces ducting and associated pressure losses, reduces the size of the system, and increases the overall efficiency of the system which in turn allows a reduction in fan size and power requirements. The compact arrangement allows the system to be placed underneath, and preferably inside most automobile seats, which further reduces ducting and associated pressure losses, and allows further reductions in motor size and power. The result of the various reductions is some combination of a smaller system volume, less power consumption, smaller size, and generation of less noise, than previously available.
Advantageously, a seal separates the opposing sides of the rotating, annular heat exchangers to form a main, or supply side and a waste side. Air enters the assembly near the axis of rotation, which advantageously is aligned with the motor's rotational axis. The air exits radially or axially outward into a housing enclosing the majority of the annular fan/heat exchanger. An outlet in fluid communication with the main (or supply) side is in fluid communication with the seat of a passenger vehicle. An outlet in fluid communication with the waste side is also in fluid communication with an outlet at a location that will not degrade performance by allowing the waste air to be recirculated to the air entry portion. The thermoelectric creates a temperature differential between the supply side air and the waste side air. Layers of thermal insulation between the waste side and the supply side help maintain that temperature differential in portions of the assembly.
Power is supplied to the thermoelectric device by brush and slip ring assemblies on the rotational axis of the motor. When appropriate voltages and currents are applied to the thermoelectric and the motor, a flow of either cold or hot air is provided to the supply side by the heat exchanger that conducts the temperature differential throughout the heat exchanger, and heats or cools the air passing over the heat exchanger/fan blades by conduction and convection. Voltage adjustments to the motor and thermoelectric control the pressure, temperature and flow rate.
Advantageously, around a portion of the inside of the housing enclosing the annular fans, a wicking material is placed so that the material extends from the supply side to the waste side. If moisture condenses on one rotating fan, it is urged against the wicking material by centrifugal force from the rotating fan/heat exchanger. The wicking material absorbs the moisture, and transports the moisture to the opposing side where heated air evaporates the moisture and carries the moisture out of the system.
There is thus advantageously provided a system for thermally conditioning a
Amerigon
Doerrler William
Knobbe Martens Olson & Bear LLP
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