A thermal diode in this sense is a device whose thermal resistance is different for heat flow in one direction than for heat flow in the other direction. I.e., when the thermal diode's first terminal is hotter than the second, heat will flow easily from the first to the second, but when the second terminal is hotter than the first, little heat will flow from the second to the first.
Such an effect was first observed in a copper–cuprous-oxide interface by Chauncey Starr in the 1930s. Beginning in 2002, theoretical models were proposed to explain this effect. In 2006 the first microscopic solid-state thermal diodes were built.[1] In April 2015 Italian researchers at CNR announced development of a working thermal diode,[2] publishing results in Nature Nanotechnology.[3]
Thermal siphons can act as a one-way heat flow. Heat pipes operating in gravity may also have this effect.
Electrical diode thermal effect or functionedit
A sensor device embedded on microprocessors used to monitor the temperature of the processor's die is also known as a "thermal diode".
This application of thermal diode is based on the property of electrical diodes to change voltage across it linearly according to temperature. As the temperature increases, diodes' forward voltage decreases. Microprocessors having high clock rate encounter high thermal loads. To monitor the temperature limits thermal diodes are used. They are usually placed in that part of the processor core where highest temperature is encountered. Voltage developed across it varies with the temperature of the diode. All modern AMD and Intel CPUs, as well as AMD and Nvidia GPUs have on-chip thermal diodes. As the sensor is located directly on the processor die, it provides most local and relevant CPU and GPU temperature readings. The silicon diodes have temperature dependency of -2mV per degree Celsius. Thus the junction temperature can be determined by passing a set current through the diode and then measuring voltage developed across it. In addition to processors, the same technology is widely used in dedicated temperature sensor IC's.
As of 2009 a team at MIT is working for construction of thermal diodes that convert heat to electricity at lower temperatures than before.[4] This can be used in construction of engines or in electricity production. The efficiency of present thermal diodes is about 18% between the temperature range of 200-300 degree Celsius.[5]
^Martínez-Pérez, Maria José; Fornieri, Antonio; Giazotto, Francesco (2015). "Rectification of electronic heat current by a hybrid thermal diode". Nature Nanotechnology. 10 (4): 303–307. arXiv:1403.3052. Bibcode:2015NatNa..10..303M. doi:10.1038/nnano.2015.11. PMID 25705868. S2CID 11654721.
^. www.trnmag.com. Archived from the original on 26 February 2009. Retrieved 14 January 2022.
External linksedit
A news article on the increases in semiconductor thermal diode efficiency
Thermoelectric Power Generation: Converting Low-Grade Heat into Electricity (Equations for semiconductor thermal diodes)
January 01, 1970
thermal, diode, term, thermal, diode, refer, possibly, electrical, device, which, allows, heat, flow, preferentially, direction, electrical, semiconductor, diode, reference, thermal, effect, function, describe, both, situations, where, electrical, diode, used,. The term thermal diode can refer to a possibly non electrical device which allows heat to flow preferentially in one direction an electrical semiconductor diode in reference to a thermal effect or function or it may describe both situations where an electrical diode is used as a heat pump or thermoelectric cooler Contents 1 One way heat flow 2 Electrical diode thermal effect or function 3 Thermoelectric heat pump or cooler 3 1 Peltier devices 4 Advancements 5 See also 6 References 7 External linksOne way heat flow editA thermal diode in this sense is a device whose thermal resistance is different for heat flow in one direction than for heat flow in the other direction I e when the thermal diode s first terminal is hotter than the second heat will flow easily from the first to the second but when the second terminal is hotter than the first little heat will flow from the second to the first Such an effect was first observed in a copper cuprous oxide interface by Chauncey Starr in the 1930s Beginning in 2002 theoretical models were proposed to explain this effect In 2006 the first microscopic solid state thermal diodes were built 1 In April 2015 Italian researchers at CNR announced development of a working thermal diode 2 publishing results in Nature Nanotechnology 3 Thermal siphons can act as a one way heat flow Heat pipes operating in gravity may also have this effect Electrical diode thermal effect or function editA sensor device embedded on microprocessors used to monitor the temperature of the processor s die is also known as a thermal diode This application of thermal diode is based on the property of electrical diodes to change voltage across it linearly according to temperature As the temperature increases diodes forward voltage decreases Microprocessors having high clock rate encounter high thermal loads To monitor the temperature limits thermal diodes are used They are usually placed in that part of the processor core where highest temperature is encountered Voltage developed across it varies with the temperature of the diode All modern AMD and Intel CPUs as well as AMD and Nvidia GPUs have on chip thermal diodes As the sensor is located directly on the processor die it provides most local and relevant CPU and GPU temperature readings The silicon diodes have temperature dependency of 2mV per degree Celsius Thus the junction temperature can be determined by passing a set current through the diode and then measuring voltage developed across it In addition to processors the same technology is widely used in dedicated temperature sensor IC s Thermoelectric heat pump or cooler editThere are two types One uses semiconductor or less efficient metal i e thermocouples working on the principles of the Peltier Seebeck effect The other relies on vacuum tubes and the principles of thermionic emission Peltier devices edit a heat engine working backwards as a refrigerator such as a Peltier device diode Advancements editAs of 2009 a team at MIT is working for construction of thermal diodes that convert heat to electricity at lower temperatures than before 4 This can be used in construction of engines or in electricity production The efficiency of present thermal diodes is about 18 between the temperature range of 200 300 degree Celsius 5 See also editDrinking bird Loop heat pipe ThermosiphonReferences edit Wang Lei Li Baoweng March 2008 Phononics gets hot Physics World 21 3 27 29 Bibcode 2008PhyW 21c 27W doi 10 1088 2058 7058 21 03 31 https www cnr it it comunicato stampa 6045 CNR Diodo termico dove il calore va a senso unico Martinez Perez Maria Jose Fornieri Antonio Giazotto Francesco 2015 Rectification of electronic heat current by a hybrid thermal diode Nature Nanotechnology 10 4 303 307 arXiv 1403 3052 Bibcode 2015NatNa 10 303M doi 10 1038 nnano 2015 11 PMID 25705868 S2CID 11654721 MIT News Turning heat to electricity Chips turn more heat to power TRN 121901 www trnmag com Archived from the original on 26 February 2009 Retrieved 14 January 2022 External links editA news article on the increases in semiconductor thermal diode efficiency Thermoelectric Power Generation Converting Low Grade Heat into Electricity Equations for semiconductor thermal diodes Retrieved from https en wikipedia org w index php title Thermal diode amp oldid 1173024368, wikipedia, wiki, book, books, library,
