US20070234742A1

US20070234742A1 - Heating and cooling device

Info

Publication number: US20070234742A1
Application number: US11/784,108
Authority: US
Inventors: Shinji Aoki; Yuji Ito
Original assignee: Denso Corp
Current assignee: Denso Corp
Priority date: 2006-04-07
Filing date: 2007-04-05
Publication date: 2007-10-11
Also published as: JP2007297034A

Abstract

A heating and cooling device includes a case having an air passage, a blower for sending air to the air passage, a thermoelectric conversion element and a controller. The thermoelectric conversion element is disposed in the case, and has a heat-absorbing part and a heat-emitting part, which are switched based on a current direction. The thermoelectric conversion element heats or cools air sent by the blower by switching the current direction. The controller stops electricity supplied to the thermoelectric conversion element, when air sent by the blower toward the thermoelectric conversion element is stopped while the thermoelectric conversion element is supplied with electricity.

Description

CROSS REFERENCE TO RELATED APPLICATION

This application is based on Japanese Patent Applications No. 2006-106785 filed on Apr. 7, 2006, and No. 2006-355966 filed on Dec. 28, 2006, the disclosure of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention relates to a heating and cooling device having a thermoelectric conversion element.
2. Description of Related Art
JP-A-2006-21572 discloses a heating and cooling device. The heating and cooling device includes a Peltier element (thermoelectric conversion element) and a fan, and is disposed in a seat of a vehicle. A hole for blowing air and a duct communicating with the hole are provided in the seat. The Peltier element converts electricity into heat, and the fan sends air toward the hole.
When air is cooled at a low-temperature side of the Peltier element and the cooled air is blown through the hole, heat generated at a high-temperature side of the Peltier element is exhausted outside of the vehicle. When air is heated at a high-temperature side of the Peltier element and the heated air is blown through the hole, cold energy generated at a low-temperature side of the Peltier element is exhausted outside of the vehicle.
Further, a voltage applied to the Peltier element and an amount of air sent by the fan are controlled in a combination. Thus, a temperature of air blown through the hole can be controlled.
When the Peltier element is in an operating condition, the fan is also in an operating condition to send air to the Peltier element. However, when the fan is stopped for any reason even though the fan and the Peltier element are in the operating condition, air is not sent to the Peltier element, for example.
At this time, the Peltier element may be overheated, because air is not sent to the Peltier element. Therefore, a temperature of the Peltier element may be abnormally increased. Moreover, when the Peltier element has a possibility to have the high temperature, a cushion material adjacent to the Peltier element is required to have a high heat-resistance. Thus, cost for manufacturing the heating and cooling device may be increased.

SUMMARY OF THE INVENTION

In view of the foregoing and other problems, it is an object of the present invention to provide a heating and cooling device.
According to an example of the present invention, a heating and cooling device includes a case having an air passage, a blower for sending air to the air passage, a thermoelectric conversion element and a controller. The thermoelectric conversion element is disposed in the case, and has a heat-absorbing part and a heat-emitting part, which are switched based on a current direction. The thermoelectric conversion element heats or cools air sent by the blower by switching the current direction. The controller stops electricity supplied to the thermoelectric conversion element, when air sent by the blower toward the thermoelectric conversion element is stopped while the thermoelectric conversion element is supplied with electricity.
Accordingly, an abnormal temperature increasing of the Peltier element can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description made with reference to the accompanying drawings. In the drawings:

FIG. 1 is a schematic diagram showing a heating and cooling device according to a first embodiment of the present invention;

FIG. 2 is a schematic electrical circuit diagram showing the heating and cooling device;

FIG. 3 is a flow chart showing operations of a controller of the heating and cooling device;

FIG. 4 is a schematic diagram showing a heating and cooling device according to a second embodiment;

FIG. 5 is a flow chart showing operations of a controller of the heating and cooling device of the second embodiment;

FIG. 6 is a graph showing relationships between an amount of air and a static pressure, or a number of revolutions;

FIG. 7 is a schematic electrical circuit diagram showing a heating and cooling device according to a third embodiment; and

FIG. 8 is a flow chart showing operations of a controller of the heating and cooling device of the third embodiment.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

First Embodiment

A first embodiment will be described with reference to FIGS. 1-3. As shown in FIG. 1, a seat 1 includes a seat back 1 a and a seat bottom 1 b, and a heating and cooling device 5 is used in each of the seat back 1 a and the seat bottom 1 b. A first space 4 a is provided in the seat back 1 a, and a second space 4 b is provided in the seat bottom 1 b. A controller 10 shown in FIG. 2 controls the heating and cooling device 5.
A first duct 3 a communicating with the first space 4 a is provided in the seat back 1 a, and plural air-blowing holes 2 communicating with the first duct 3 a are provided in the seat back 1 a. A second duct 3 b communicating with the second space 4 b is provided in the seat bottom 1 b, and plural air-blowing holes 2 communicating with the second duct 3 b are provided in the seat bottom 1 b.
The heating and cooling device 5 is arranged in each of the first space 4 a and the second space 4 b. Specifically, the heating and cooling device 5 is supported by a net-shaped supporting member 7, and the supporting member 7 is constructed with a spring for supporting a cushion material (not shown) disposed in the seat 1.
The heating and cooling device 5 in the seat back 1 a includes a case 50 having an air passage 50 a, a blower 51A for sending air to the air passage 50 a and a Peltier element 52A disposed in the air passage 50 a of the case 50. The heating and cooling device 5 in the seat bottom 1 b includes the case 50 having the air passage 50 a, a blower 51B for sending air to the air passage 50 a and a Peltier element 52B disposed in the air passage 50 a of the case 50.
The Peltier element 52A, 52B is a thermoelectric conversion element in the first embodiment. The blower 51A, 51B introduces air from a vehicle compartment into the seat 1, and sends the introduced air toward the hole 2 through the Peltier element 52A, 52B. Further, the blower 51A, 51B includes a fan 511 and a motor 512 for driving the fan 511.
A brushless motor is used as the motor 512, and controlled by the controller 10 (to be described below) in response to a revolution signal of a pulse-width modulation (PWM) control. Further, as shown in FIG. 2, the motor 512 has a hall element 51 a (revolution signal detecting portion) for detecting operation state of the blower 51A, 51B. A revolution signal detected by the hall element 51 a is input into the controller 10.
That is, the hall element 51 a detects the operation state of the blower 51A, 51B as magnetic data, and the magnetic data are electrically converted into a detected revolution signal. When the motor 512 is revolving, the detected revolution signal is output into the controller 10.
However, air sent by the blower 51A, 51B toward the Peltier element 52A, 52B may be stopped for some sort of reason. For example, the blower 51A, 51B stops and is in a lock state, the detected revolution signal is not output into the controller 10. Therefore, the detected revolution signal may be intermittently output at this time.
The Peltier element 52A, 52B is a known thermoelectric conversion element, and converts electricity into heat. The Peltier element 52A, 52B includes a first heat exchanger 52 a and a second heat exchanger 52 b, as shown in FIG. 1. When the first heat exchanger 52 a operates as a heat-absorbing part, the second heat exchanger 52 b operates as a heat-emitting part. When the first heat exchanger 52 a operates as the heat-emitting part, the second heat exchanger 52 b operates as the heat-absorbing part. The heat-absorbing part and the heat-emitting part can be switched based on a direction of current flowing through the Peltier element 52A, 52B. The Peltier element 52A, 52B is electrically connected to a direct-current power source (not shown).
Each of the first and second heat exchangers 52 a, 52 b has an electrode (not shown) connected to a thermoelectric semiconductor therein, and plural fins for emitting or absorbing heat thereon. Each of the first and second heat exchangers 52 a, 52 b heats or cools air introduced from the vehicle compartment by the blower 51A, 51B, and the heating operation and the cooling operation can be switched by changing the direction of current. When air sent by the blower 51A, 51B toward the Peltier element 52A, 52B is stopped, a temperature of the Peltier element 52A, 52B may be abnormally increased.
In the first embodiment, a direct current is applied to the Peltier element 52A, 52B such that the first heat exchanger 52 a becomes the heat-absorbing part and that the second heat exchanger 52 b becomes the heat-emitting part. At this time, the first heat exchanger 52 a cools air introduced from the vehicle compartment, and the second heat exchanger 52 b heats air introduced from the vehicle compartment. A downstream side of the first heat exchanger 52 a is connected to the duct 3 a, 3 b.
Further, a downstream side of the second heat exchanger 52 b is connected to an exhaust duct 6 a, 6 b communicating with outside of the seat 1. The exhaust duct 6 a (6 b) and the duct 3 a (3 b) are separated by a separation board (not shown). Therefore, air-conditioning air cooled by the first heat exchanger 52 a and exhaust air heated by the second heat exchanger 52 b do not mix with each other.
In the first embodiment, a downstream end of the exhaust duct 6 a, 6 b is open to outside of the seat 1. However, the downstream end of the exhaust duct 6 a, 6 b may be extended to outside of the vehicle. A temperature sensor 53A, 53B (temperature detecting portion) detects a temperature of air blown from the first heat exchanger 52 a to the duct 3 a, 3 b.
The temperature sensor 53A, 53B is disposed at a downstream end of the first heat exchanger 52 a. Therefore, the temperature sensor 53A, 53B can detect an element temperature of the first heat exchanger 52 a of the Peltier element 52A, 52B. When the blower 51A, 51B stops for some sort of reason, the element temperature can be detected by the temperature sensor 53A, 53B. The temperature sensor 53A, 53B is electrically connected to the controller 10 to output the detected temperature, as shown in FIG. 2. In addition, a temperature sensor (not shown) for detecting a temperature of air blown into the exhaust duct 6 a, 6 b is disposed at a downstream end of the second heat exchanger 52 b. This temperature sensor is also electrically connected to the controller 10 to output the detected temperature.
The controller 10 is arranged in either one of the space 4 a or the space 4 b, and is constructed with a microcomputer as a main part. A ROM (not shown) is arranged in the controller 10, and a predetermined air-conditioning program is stored in the ROM.
The controller 10 controls the blower 51A, 51B and electricity supplied to the Peltier element 52A, 52B based on the temperature detected by the temperature sensor 53A, 53B. Further, an inside temperature sensor (not shown) detects a compartment temperature, an outside temperature sensor (not shown) detects an outside air temperature, a solar radiation sensor (not shown) detects an amount of solar radiation, and instruction by an occupant is input into an operation panel (not shown). The controller 10 controls the blower 51A, 51B and electricity supplied to the Peltier element 52A, 52B based on the compartment temperature, the outside air temperature, the amount of solar radiation and the instruction.
Further, a target temperature can be set for the heating and cooling device 5 by using a temperature-adjusting switch (not shown) provided in the operation panel. An actuation switch 11 shown in FIG. 2 is also provided in the operation panel.
FIG. 2 shows an electrical circuit diagram of the blower 51A, 51B and the Peltier element 52A, 52B, which are controlled by the controller 10. The controller 10 has a positive electrode side power terminal B+, a negative electrode side power terminal B−, a revolution signal output terminal NT1 and a revolution signal input terminal NT2, in order to be connected to the motor 512 of the blower 51A, 51B.
Each terminal B+, B−, NT1, NT2 is connected to the motor 512 of the blower 51A for the seat back 1 a, and the motor 512 of the blower 51B for the seat bottom 1 b. Each motor 512 has a power input terminal 51 b, a power output terminal 51 c, a revolution signal input terminal 51 d and an output terminal 51 e for the hall element 51 a.
The power input terminal 51 b is connected to the positive electrode side power terminal B+. The power output terminal 51 c is connected to the negative electrode side power terminal B−. The revolution signal input terminal 51 d is connected to the revolution signal output terminal NT1. The output terminal 51 e is connected to the revolution signal input terminal NT2. When the actuation switch 11 is turned on, the blower 51A, 51B are actuated.
The Peltier element 52B for the seat bottom 1 b and the Peltier element 52A for the seat back 1 a are electrically connected to the controller 10 in series. The controller 10 has a positive electrode side power terminal TED+, a negative electrode side power terminal TED−, potential input terminals VT1, VT2, VT3 and connection terminals TC, TCS, TB, TBS for the temperature sensor 53A, 53B.
The Peltier element 52A, 52B has a power input terminal 52 c, a power output terminal 52 d and a potential detection terminal 52 e. The positive electrode side power terminal TED+ is connected to the power input terminal 52 c of the Peltier 52B for the seat bottom 1 b. The negative electrode side power terminal TED− is connected to the power output terminal 52 d of the Peltier 52A for the seat back 1 a. The potential input terminal VT1 is connected to the potential detection terminal 52 e of the Peltier 52B for the seat bottom 1 b. The potential input terminal VT3 is connected to the potential detection terminal 52 e of the Peltier 52A for the seat back 1 a.
The power output terminal 52 d of the Peltier 52B for the seat bottom 1 b is connected to the power input terminal 52 c of the Peltier 52A for the seat back 1 a. A potential detection terminal 52 f is electrically provided between the power output terminal 52 d of the Peltier 52B for the seat bottom 1 b and the power input terminal 52 c of the Peltier 52A for the seat back 1 a. The potential detection terminal 52 f is connected to the potential input terminal VT2.
Each temperature sensor 53A, 53B has connection terminals 53 a, 53 b. The connection terminal 53 a of the temperature sensor 53B for the seat bottom 1 b is connected to the connection terminal TC. The connection terminal 53 b of the temperature sensor 53B for the seat bottom 1 b is connected to the connection terminal TCS. The connection terminal 53 a of the temperature sensor 53A for the seat back 1 a is connected to the connection terminal TB. The connection terminal 53 b of the temperature sensor 53A for the seat back 1 a is connected to the connection terminal TBS.
FIG. 3 shows operations of the heating and cooling device 5. At step 110, an air-conditioning control program is started by turning on the actuation switch 11. Then, at step 120, heat load data are detected. Specifically, a target temperature set by an occupant is detected, and temperature data and solar radiation data output from the above-described sensors are detected.
At step 130, a target temperature for air blown from the Peltier element 52A, 52B is calculated based on the heat load data. Then, the element temperature of the Peltier element 52A, 52B and amount of air blown through the Peltier element 52A, 52B are calculated based on the target temperature. Further, a target number of revolutions for the blower 51A, 51B is calculated based on the amount of air. Furthermore, a voltage to be applied to the Peltier element 52A, 52B is calculated based on the element temperature.
At step 140, a target revolution signal having the calculated target number of revolutions is output from the output terminal NT1 into the input terminal 51 d to drive the blower 51A, 51B, and the calculated voltage is applied to the Peltier element 52A, 52B to actuate the Peltier element 52A, 52B.
Thereby, air cooled by the first heat exchanger 52 a is blown through the hole 2 of the seat 1, and air heated by the second heat exchanger 52 b is exhausted outside of the seat 1. Thus, air-conditioning operation for the seat 1 can be performed. Then, at step 150, the target revolution signal is determined to be output from the output terminal NT1 into the input terminal 51 d or not. That is, the target revolution signal is monitored. When the target revolution signal is output, operation is determined to be normal, and moves to step 160. When the target revolution signal is not output, operation is determined to be abnormal, and moves to step 190.
At step 160, a revolution signal detected by the hall element 51 a is determined to be input from the output terminal 51 e for the hall element 51 a into the input terminal NT2 or not. That is, the detected revolution signal is monitored. When the detected revolution signal is input, operation is determined to be normal, and moves to step 170. When the detected revolution signal is not input, operation is determined to be abnormal, and moves to step 190.
Here, the revolution signal is detected after a predetermined time period (e.g., about 4-10 seconds) passes. If the time period is increased, the element temperature of the Peltier element 52A, 52B may be rapidly increased. The time period may be reduced less than 4 seconds. However, when the time period is too much reduced, signal glitch (error) may be detected.
At step 170, the element temperature is determined to be equal to or smaller than a predetermined temperature R1 (e.g., about 80° C.) or not. That is, the element temperature detected by the temperature sensor 53A, 53B is monitored. When the element temperature is equal to or smaller than the predetermined temperature R1, operation is determined to be normal, and moves to step 180. When the element temperature is larger than the predetermined temperature R1, operation is determined to be abnormal, and moves to step 190.
When voltage is applied to the Peltier element 52A, 52B and air sent by the blower 51A, 51B toward the Peltier element 52A, 52B is stopped, the element temperature is rapidly increased. Therefore, the lock state of the blower 51A, 51B or dust-clogging in the air passage 50 a can be detected by detecting the element temperature, when the amount of air is small or when the blower 51A, 51B stops. When the operations are determined to be normal at the above-described three steps 150, 160, 170, the blower 51A, 51B and the Peltier element 52A, 52B are kept operating, at step 180.
If at least one of the operations is determined to be abnormal at the above-described three steps 150, 160, 170, the blower 51A, 51B is determined to stop and be in the lock state. That is, air sent by the blower 51A, 51B toward the Peltier element 52A, 52B is determined to be stopped. Therefore, at step 190, the Peltier element 52A, 52B and the blower 51A, 51B are stopped by the controller 10.
Due to the above-described three steps 150, 160, 170, air sent by the blower 51A, 51B toward the Peltier element 52A, 52B can be easily determined to be stopped. Further, abnormal temperature increasing of the Peltier element 52A, 52B can be reduced, because electricity supplied to the Peltier element 52A, 52B can be stopped when air is not sent toward the Peltier element 52A, 52B.
According to the first embodiment, the lock state of the blower 51A, 51B can be easily detected by detecting that the blower 51A, 51B stops while the blower 51A, 51B is controlled to operate. At this time, the abnormal temperature increasing of the Peltier element 52A, 52B can be stopped by stopping electricity supplied to the Peltier element 52A, 52B.
When the target revolution signal output into the blower 51A, 51B is stopped, electricity supplied to the Peltier element 52A, 52B is stopped. The stop state of the blower 51A, 51B can be easily detected by detecting that the target revolution signal is not output into the blower 51A, 51B.
Further, the blower 51A, 51B has the hall element 51 a for detecting a driving state of the blower 51A, 51B. When a detection signal is not input into the controller 10 from the hall element 51 a, electricity supplied to the Peltier element 52A, 52B is stopped. Due to the hall element 51 a, the stop state of the blower 51A, 51B can be easily detected. Furthermore, when the detection signal is not input into the controller 10 from the hall element 51 a for a predetermined or more time period, electricity supplied to the Peltier element 52A, 52B is stopped. For example, when the detection signal is not input for four or more seconds, the lock state of the blower 51A, 51B can be easily detected.
Further, the Peltier element 52A, 52B has the temperature sensor 53A, 53B for detecting the element temperature of the Peltier element 52A, 52B. When the element temperature is larger than the predetermined temperature R1, electricity supplied to the Peltier element 52A, 52B is stopped. Thus, the abnormal temperature increasing of the Peltier element 52A, 52B can be reduced. Furthermore, the abnormal temperature increasing of the Peltier element 52A, 52B can be monitored by the above-described three detecting steps 150, 160, 170.

Second Embodiment

A second embodiment will be described with reference to FIGS. 4-6. As shown in FIG. 4, a duct 54 is disposed between the blower 51A, 51B and the Peltier element 52A, 52B in the second embodiment.
Specifically, the duct 54 has a wave shape. An end of the duct 54 is connected to a discharge side of the blower 51A, 51B, and the other end of the duct 54 is connected to the case 50 of the Peltier element 52A, 52B. Thereby, the heating and cooling device 5 can be easily mounted in the space 4 a, 4 b of the seat 1 having a complicated shape.
When electricity is supplied to the Peltier element 52A, 52B, the duct 54 may be disconnected (detached) by vibration of the vehicle. The disconnection of the duct 54 can be detected in the second embodiment.
Specifically, as shown in FIG. 5, step 165 is provided between step 160 and step 170. At step 165, the number N of revolutions of the detected revolution signal input at step 160 is compared with a predetermined number R2 of revolutions. The number N of revolutions of the detected revolution signal is determined to be equal to or larger than the predetermined number R2 of revolutions or not. That is, the number N of revolutions of the detected revolution signal detected by the hall element 51 a is monitored.
Here, when the number N of revolutions of the detected revolution signal is determined to be equal to or larger than the predetermined number R2 of revolutions, operation moves to step 170. When the number N of revolutions of the detected revolution signal is determined to be smaller than the predetermined number R2 of revolutions, operation is determined to be abnormal, and moves to step 190.
At step 165, the duct 54 is determined to be disconnected or not. When the number N of revolutions of the detected revolution signal is smaller than the predetermined number R2 of revolutions, the duct 54 is determined to be disconnected.
A reason for this determination will be described with reference to FIG. 6. A solid line in FIG. 6 shows a pressure characteristic X1, which is a relationship between a static pressure and an amount of air when the duct 54 is normally mounted between the blower 51A, 51B and the Peltier element 52A, 52B. At this time, the blower 51A, 51B has a number Y1 of revolutions.
A dashed line in FIG. 6 shows a pressure characteristic X2, which is a relationship between a pressure and an amount of air when the duct 54 is disconnected from the Peltier element 52A, 52B. At this time, the blower 51A, 51B has a number Y2 of revolutions. That is, when the duct 54 is disconnected, the number of revolutions is decreased from Y1 to Y2. Therefore, the disconnection of the duct 54 can be detected by monitoring the detected number N of revolutions, at step 165.
According to the second embodiment, the disconnection of the duct 54 can be easily detected. Further, the number of revolutions of the blower 51A, 51B can be easily detected by the number N of revolutions of the revolution signal detected by the hall element 51 a. The other parts in the second embodiment may be made similar to the first embodiment.

Third Embodiment

A third embodiment will be described with reference to FIGS. 7 and 8. In the above embodiments, the hall element 51 a detects the driving state of the blower 51A, 51B, when a brushless motor is used as the motor 512. However, when a motor having brush is used as the motor 512, current flowing through the blower 51A, 51B can be detected.
Specifically, as shown in FIG. 7, the controller 10 has the positive electrode side power terminal B+, the negative electrode side power terminal B− and a driving current input terminal Ip, in order to be connected to the motor 512 of the blower 51A, 51B. Further, the motor 512 of the blower 51A, 51B has the power input terminal 51 b, the power output terminal 51 c and a driving current detection terminal 51 f.
The power input terminal 51 b is connected to the positive electrode side power terminal B+. The power output terminal 51 c is connected to the negative electrode side power terminal B−. The driving current detection terminal 51 f is connected to the driving current input terminal Ip. Then, as shown in FIG. 8, at step 160 a, a driving current flowing from the driving current detection terminal 51 f into the driving current input terminal Ip is determined to be equal to or smaller than a predetermined value R3 or not.
Here, this determination is performed in order to monitor the driving current flowing through the blower 51A, 51B. When the driving current is equal to or smaller than the predetermined value R3, operation is determined to be normal and moves to step 170. When the driving current is larger than the predetermined value R3, operation is determined to be abnormal and moves to step 190.
That is, the driving current is increased when the blower 51A, 51B stops and is in the lock state for some sort of reason, and this characteristic is used for detecting the lock state of the blower 51A, 51B. Thereby, the lock state of the blower 51A, 5B can be easily detected. The other parts in the third embodiment may be made similar to the first and second embodiments.

Other Embodiments

In the above embodiments, the heating and cooling device 5 is arranged in each of the seat back 1 a and the seat bottom 1 b. However, when the Peltier element 52A is arranged in the seat back 1 a and the Peltier element 52B is arranged in the seat bottom 1 b, the blower 51B may not be arranged in the seat bottom 1 b, and the blower 51A can send air toward the Peltier element 52B of the seat bottom 1 b through a duct. Alternatively, the blower 51A may not be arranged in the seat back 1 a, and the blower 51B can send air toward the Peltier element 52A of the seat back 1 a through a duct.
Further, in the above embodiments, the first heat exchanger 52 a cools air, and the second heat exchanger 52 b heats air. Alternatively, the first heat exchanger 52 a may heat air, and the second heat exchanger 52 b may cool air.
Further, in the above embodiments, the single controller 10 is used. Alternatively, the heating and cooling device 5 may be electrically connected to a vehicle air-conditioning controller, and the heat load may be detected by the vehicle air-conditioning controller at step 120 shown in FIGS. 3, 5 and 8. Furthermore, the controller 10 and the vehicle air-conditioning controller may be constructed in a combination.
Further, in the above embodiments, the controller 10 is arranged in either one of the space 4 a or the space 4 b in the seat 1. Alternatively, the controller 10 may be arranged adjacent to the seat 1.
Such changes and modifications are to be understood as being within the scope of the present invention as defined by the appended claims.

Claims

1. A heating and cooling device comprising:

a case having an air passage;

a blower for sending air to the air passage;

a thermoelectric conversion element disposed in the case, wherein the thermoelectric conversion element has a heat-absorbing part and a heat-emitting part, which are switched based on a current direction, and heats or cools air sent by the blower by switching the current direction; and

a controller for stopping electricity supplied to the thermoelectric conversion element, when air sent by the blower toward the thermoelectric conversion element is stopped while the thermoelectric conversion element is supplied with electricity.

2. The heating and cooling device according to claim 1, wherein

the controller stops electricity supplied to the thermoelectric conversion element, when the blower stops sending air.

3. The heating and cooling device according to claim 2, wherein

the controller stops electricity supplied to the thermoelectric conversion element, when the controller detects that a driving signal output into the blower stops.

4. The heating and cooling device according to claim 2, wherein

the blower includes a revolution signal detecting portion for detecting a driving state of the blower, and

the controller stops electricity supplied to the thermoelectric conversion element, when the controller detects that a detection signal input into the controller from the revolution signal detecting portion stops.

5. The heating and cooling device according to claim 4, wherein

the controller stops electricity supplied to the thermoelectric conversion element, when the controller detects that the detection signal stops for a time period equal to or longer than a predetermined time period.

6. The heating and cooling device according to claim 1, further comprising:

a duct, through which the blower and the thermoelectric conversion element are connected, wherein

air sent by the blower toward the thermoelectric conversion element is stopped, when the duct is disconnected between the blower and the thermoelectric conversion element, and

the controller stops electricity supplied to the thermoelectric conversion element, when the controller detects a disconnection of the duct.

7. The heating and cooling device according to claim 6, wherein

the controller stops electricity supplied to the thermoelectric conversion element, when the controller detects that a detection signal output from the revolution signal detecting portion has a number of revolutions equal to or smaller than a predetermined value.

8. The heating and cooling device according to claim 7, wherein

the controller stops electricity supplied to the thermoelectric conversion element, when the controller detect that the detection signal stops for a time period equal to or longer than a predetermined time period.

9. The heating and cooling device according to claim 1, wherein

the controller stops electricity supplied to the thermoelectric conversion element, when the controller detects that a driving current flowing through the blower is equal to or larger than a predetermined value.

10. The heating and cooling device according to claim 1, wherein

the thermoelectric conversion element includes a temperature detection portion for detecting an element temperature of the thermoelectric conversion element, and

the controller stops electricity supplied to the thermoelectric conversion element, when the controller detects that the element temperature is equal to or larger than a predetermined temperature.

11. The heating and cooling device according to claim 1, wherein

the blower and the thermoelectric conversion element are disposed in a seat having an air-blowing hole thereon and a duct therein.