Assignment#01: Literature Survey on Sensors and Actuators ECE5320 Mechatronics Assignment#01: Literature Survey on Sensors and Actuators Topic: Peltier Heat Pump Prepared by: Jared Schmidt Dept. of Electrical and Computer Engineering Utah State University E: F: (435) (ECE Dept.) 3/9/2012

5/13/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-2 Outline –Reference list –To probe further –Major applications –Basic working principle illustrated –A typical sample configuration in application (application notes) –Major specifications –Limitations –Purchasing information

5/13/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-3 Reference list “Thermoelectric cooling”; Wikipedia.org; en.wikipedia.org/wiki/Thermoelectric_cooling en.wikipedia.org/wiki/Thermoelectric_cooling “Thermoelectric effect”; Wikipedia.org; en.wikipedia.org/wiki/Thermoelectric_effect en.wikipedia.org/wiki/Thermoelectric_effect Duckworth, Henry E.; Electricity and Magnetism; pp ; New York: Holt, Rinehart and Winston (1960) “Peltier effect”; The Encyclopedia of Science; fect.html fect.html

5/13/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-4 To explore further (survival pointers of web references etc) “Thermoelectric Devices: Solid-State Refrigerators and Electrical Generators in the Classroom”; Edmund J. Winder, Arthur B. Ellis, and George C. Lisensky; Journal of Chemical Education; 1996; 73 (10), 940

Major applications Instrument cooling CPU cooling Beverage cooling/heating Refrigeration Fiber optic laser cooling Thermistor cooling 5/13/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-5 Thermoelectric USB beverage cooler Photo from Wikipedia.org

Major applications In general thermoelectric cooling is used for: –Cooling in limited spaces –Cooling small devices –Cooling in devices requiring quiet or silent operation 5/13/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-6 Peltier Heat Pump Photo from Wikipedia.org

Major applications Since Peltier heat pumps create a temperature difference and not an absolute temperature, they are sometimes stacked serially to get larger temperature differences between the ends of the stack. 5/13/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-7 Three stage Peltier cooler from

Basic Working Principle “The Peltier effect is the presence of heat at an electrified junction of two different metals” (Wikipedia) 5/13/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-8 From Duckworth, Electricity & Magnetism, p 181 Example

Basic Working Principle The Peltier effect is related to the Seebeck effect and the Thompson effect. –Seebeck effect says that a temperature difference between dissimilar junctions will create a voltage difference. –Thompson effect says a current carrying conductor with a temperature difference on it between two points will absorb or expel heat. 5/13/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-9

Basic Working Principle The conduction occurs in the levels of the highest energy electrons the atom has. For different elements, this energy level is slightly different. When electrons are forced to move through the junction of two dissimilar metals, the electrons have to overcome an energy level difference to move through junction. 5/13/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-10

Basic Working Principle An electron going from a lower energy level to a higher energy level (across a junction) needs a boost of energy. In order to do this, the electron borrows energy from its surroundings, which removes heat from the junction. This is why the cold junction gets cold. 5/13/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-11

Basic Working Principle An electron going a higher energy level to a lower energy level (across a junction) expels some energy. In order to do this, the electron sheds some energy into its surroundings, which generates heat in the junction. Thus the hot junction gets hot. By reversing the current, the electrons go the opposite direction which switches which junction is hot and which junction is cold. 5/13/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-12

Basic Working Principle Often, semiconductors that have been doped with impurities are used to make solid state heater/coolers. Doped semiconductors work as well as or better than dissimilar metals at generating a temperature difference between junctions. Semiconductors don’t conduct heat as well as metals. –This allows solid state heat pumps to be made smaller. 5/13/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-13

Common Heat Pump Construction 5/13/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-14 Semiconductor Heat Pump Courtesy of Wikipedia.org “Peltier element schematic. Thermoelectric legs are thermally in parallel and electrically in series.”

Sample Configuration The picture to the right shows a heat sink attached to the hot side of two Peltier heat pumps. The cold plate can be mounted to: –a chip –a circuit board –another heat sink –anything that needs to be cooled 5/13/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-15 Peltier cooler assembly from

Major Specifications Max voltage Max current draw Temperature difference between hot and cold sides Size Max heat flux (speed of heat absorption/rejection) Price 5/13/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-16

Example Specifications Max voltage: 3.8V Max current draw: 6A Max temperature difference between hot and cold sides: 27°C Size: 20mm x 20mm x 4mm Max heat flux: 27°C Cost: $ /13/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-17 From Part Number: ND Description: Peltier Mod 20x 4mm 6.0A INP

Limitations Very low efficiency –10% of Carnot efficiency or less Heat pump cannot often be a stand-alone device –Saturation can occur quickly when heat starts moving from the hot junction to the cold junction. –Hot side must be coupled with a heat sink or some other method of heat removal. –Overheating of the heat pump can occur quickly if heat is not removed from the hot side. 5/13/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-18

Considerations When using Peltier heat pumps to cool electronics, condensation is a concern. The temperature of the cold side is usually below ambient room temperature and can result in condensation on the electronics, which may damage them. 5/13/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-19 Photo from from

Purchasing Information Many companies sell Peltier heat pumps. A few examples are: 5/13/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-20 CompanyItemCost Amazon.com6 Amp Peltier cooling module $ Shipping Opentip.com3 Amp Peltier cooling module $ Shipping Digikey.com6 Amp 4mm Peltier module $ Shipping Digikey.com6 Amp 27mm Peltier module $ Shipping Xoxide.comUSB Beverage Chiller/Warmer $ Shipping