Sizing of Pellets in Thermoelectric Modules (TEMs)

2005 ◽  
Author(s):  
Marc Hodes
Keyword(s):  
Electrical Contact ◽  
Coefficient Of Performance ◽  
Total Power ◽  
Operating Voltage ◽  
Electrical Contact Resistance ◽  
Cross Sectional ◽  
Thermoelectric Modules ◽  
Total Power Consumption ◽  
Generation Mode ◽  
Operating Current

Sizing the height and cross sectional area of the pellets within thermoelectric modules (TEMs) used to cool, heat and generate power is necessary to optimize their efficiency and/or performance. Here the heat flux that a TEM can accommodate, its coefficient of performance, and its operating current and voltage in refrigeration mode are provided as a function of pellet geometry. This enables designers to, for example, size pellets to refrigerate a load such that the total power consumption of a TEM and a power supply (that converts available voltage to that required by the TEM) is minimized. In generation mode, power output, conversion efficiency and operating voltage and current are provided as a function of pellet geometry and the electrical resistance of a load connected to a TEM. Finally, the effects of electrical contact resistance at the pellet interconnects on the aforementioned parameters are addressed.

scholarly journals Fault detection in HVAC systems using a distribution considering uncertainties

2019 ◽  
Vol 111 ◽  
pp. 05010
Author(s):  
Shohei Miyata ◽  
Yasunori Akashi ◽  
Jongyeon Lim ◽  
Yasuhiro Kuwahara
Keyword(s):  
Fault Detection ◽  
Performance Indicator ◽  
High Energy ◽  
Hvac Systems ◽  
Coefficient Of Performance ◽  
Total Power ◽  
Hvac System ◽  
Total Power Consumption ◽  
Detailed Simulation ◽  
Performance Distribution

Detecting and diagnosing faults that degrade the performance of heating, ventilation, and air conditioning (HVAC) systems is very important for maintaining high energy efficiency. The performance of HVAC systems can be evaluated by analyzing monitored data. However, data from a HVAC system generally includes uncertainties, which renders monitored data less reliable. Then, we focused on uncertainties and a calculated performance distribution. The uncertainties from sensors, actuators, and communications were modelled stochastically and were incorporated into a detailed simulation. The system coefficient of performance (SCOP) was used as a performance indicator, which is defined as the ratio of suppled heat to total power consumption. The SCOP distributions over the course of representative weeks in 2007 and 2015 were calculated by repeating the simulation 2,000 times with different uncertainties. Regarding the results for 2015, the 90% confidence interval of the distribution was -4.9% to 5.8% from the SCOP value without uncertainties. The SCOP value determined from the monitored data in 2015 was outside of the low end of the distribution though that in 2007 was inside of the interval. Through an analysis of the monitored data, it was found that fault detection is possible by comparing the monitored data with the distribution.

Microscale Thermoelectric Cooler Assembled From Bulk Materials for Thermal Management of Electronics

2008 ◽  
Author(s):  
Pradeep Mishra ◽  
Nathan Crane
Keyword(s):  
Thermal Management ◽  
Electronic Device ◽  
Bulk Material ◽  
Electrical Contact ◽  
Coefficient Of Performance ◽  
Electrical Contact Resistance ◽  
Minimum Thickness ◽  
Maximum Heat ◽  
Thermoelectric Coolers ◽  
Heat Pumping

Electronic device thermal management improvements are critical to continued increases in computing performance. Thermoelectric coolers (TECs) show promise in meeting this need. This paper compares the performance of Bismuth Telluride (BiTe) in three different forms: thin film, bulk, and a hypothetical nanostructured bulk material. This hypothetical materials is based on recent experimental demonstrations in Lead Telluride. Performances of the TEC based on the three different BiTe forms are compared with respect to heat pumping capacity and optimum thickness. The simulations are based on 1-D models that include the effects of thermal and electrical contact resistance. Simulated results show a significant enhancement in maximum heat pumping capacity of ‘Nanostrutured-Bulk TEC’. Modified definitions of heat pumping capacity and coefficient of performance (COP) are proposed for evaluating TECs used to cool objects with temperatures above ambient temperature. It is observed that the appropriate heat sink selection is key factor for achieving the improved TEC performance while maintaining minimum thickness.

A 16.4 nW, Sub-1 V, Resistor-Less Voltage Reference with BJT Voltage Divider

2018 ◽  
Vol 27 (13) ◽  
pp. 1850206 ◽  
Author(s):  
Qingshan Yang ◽  
Peiqing Han ◽  
Niansong Mei ◽  
Zhaofeng Zhang
Keyword(s):  
Low Voltage ◽  
Supply Voltage ◽  
Voltage Divider ◽  
Total Power ◽  
Cmos Process ◽  
Operating Voltage ◽  
Voltage Reference ◽  
Ultra Low Power ◽  
Silicon Area ◽  
Total Power Consumption

A 16.4[Formula: see text]nW, sub-1[Formula: see text]V voltage reference for ultra-low power low voltage applications is proposed. This design reduces the operating voltage to 0.8[Formula: see text]V by a BJT voltage divider and decreases the silicon area considerably by eliminating resistors. The PTAT and CTAT are based on SCM structures and a scaled-down [Formula: see text], respectively, to improve the process insensitivity. This work is fabricated in 0.18[Formula: see text][Formula: see text]m CMOS process with a total area of 0.0033[Formula: see text]mm2. Measured results show that it works properly for supply voltage from 0.8[Formula: see text]V to 2[Formula: see text]V. The reference voltage is 467.2[Formula: see text]mV with standard deviation ([Formula: see text]) being 12.2 mV and measured TC at best is 38.7[Formula: see text]ppm/[Formula: see text]C ranging from [Formula: see text]C to 60[Formula: see text]C. The total power consumption is 16.4[Formula: see text]nW under the minimum supply voltage at 27[Formula: see text]C.

Analysis of an Annular-Geometry Thermoelectric Module (TEM)

2007 ◽  
Author(s):  
Shankar Krishnan ◽  
Marc Hodes ◽  
Christopher Jones ◽  
Oana Malis
Keyword(s):  
Heat Dissipation ◽  
Heat Conduction Problem ◽  
Electrical Contact ◽  
Thermoelectric Module ◽  
Outer Radius ◽  
Coefficient Of Performance ◽  
Cross Sectional ◽  
Annular Geometry ◽  
In Series ◽  
Current Flows

An annular-geometry thermoelectric module (TEM) operating in refrigeration mode is analyzed. As in conventional (Cartesian geometry) TEMs, the pellets are interconnected such that current flows through them in series whilst they act in parallel with respect to conduction heat transfer. Current direction is such that Peltier cooling is provided at the inner radius of an annular TEM and heat dissipation is at its outer radius, where a boundary condition of the first kind is imposed. The cross-sectional area of each pellet increases linearly with radius. Accounting for electrical contact resistances at the interconnects, the necessary (one-dimensional) heat-conduction problem is solved to determine general expressions for the cooling rate provided by and coefficient performance of an annular TEM. Maximum cooling flux into an annular TEM and coefficient of performance for cooling fluxes below the maximum value are calculated and compared to those for conventional TEMs. Finally, the benefits of using an annular-geometry TEM are discussed.

Analysis of Refrigeration Requirements of Digital Processors in Subambient Temperatures

2010 ◽  
Vol 7 (4) ◽  
pp. 197-204 ◽  
Author(s):  
Won Ho Park ◽  
Tamer Ali ◽  
C. K. Ken Yang
Keyword(s):  
Integrated Circuits ◽  
High Performance ◽  
Power Reduction ◽  
Coefficient Of Performance ◽  
System Level ◽  
Total Power ◽  
Optimized Design ◽  
Total Power Consumption ◽  
Level Model ◽  
Viable Approach

The total power consumption for high-performance computing systems is a serious concern for designers of integrated circuits and systems. It is well known that cooling the operating temperature results in reduced electronic power and/or speed gains. However, total power dissipation includes both electronic power and the refrigeration power. This study explores the optimal operating temperatures and the amount of total power reduction at subambient temperatures. This paper presents a realistic system-level model that includes both the electronic and the refrigeration systems. Analysis using the model shows the optimal temperature, and sensitivity to parameters of the electronic and refrigeration systems. For instance, a system with 50% electronic leakage and a minimum refrigeration coefficient of performance (COP) of 3.3, the optimized design operates at 8°C and offers a 44% power reduction over the noncooled design. Analysis also shows that temperatures near that of domestic freezers is nearly optimal for digital processors and such cooling may be viable approach for current and future electronics due to the scaling trends of integrated circuits technology.

Miniaturized Thermoelectric Cooler

2002 ◽  
Author(s):  
Luciana W. da Silva ◽  
Massoud Kaviany
Keyword(s):  
Electrical Contact ◽  
Electrical Circuit ◽  
Film Deposition ◽  
Coefficient Of Performance ◽  
Optimum Number ◽  
Thermoelectric Cooler ◽  
Seebeck Coefficients ◽  
Column Type ◽  
Operating Current ◽  
P Type

Vapor-deposited bismuth telluride (n-type) and antimony telluride (p-type) films are used in a micro, column-type, patterned thermoelectric cooler. The optimum number of thermoelectric pairs and operating current are predicted. Such devices contain a number of metal/thermoelectric and metal/elecrical-insulator interfaces. In the analysis, various interfacial resistances (phonon and electron boundary resistances and thermal and electrical contact resistances) have been included. The boundary resistances cause a reduction in the thermal conductivity (desirable) and a reduction in the Seebeck coefficient (undesirable) of the thermoelectric elements. The contact resistances reduce the overall device performance. In the fabrication, the stoichiometry of the deposited thermoelectric films, the patterned film deposition, and the selection of the conducting connectors, are discussed. The thermoelectric films are about 4 μm thick and are deposited on patterned platinum (first trial layer for connectors), which are in turn deposited on oxide coated silicon wafers. The top, suspended connectors that close the electrical circuit are bonded to the surface to be cooled. The non-uniformity of the composition in the thermoelectric films influences the measured Seebeck coefficients. The analysis shows that a coefficient of performance of 0.38 is obtainable for a wireless micro sensor application.

Impact of Material Properties on Cooling COP of Integrated Thermoelectric Microcoolers

2013 ◽  
Author(s):  
Yee Rui Koh ◽  
Kazuaki Yazawa ◽  
Ali Shakouri
Keyword(s):  
Thermal Conductivity ◽  
Integrated Circuit ◽  
Hot Spot ◽  
Coefficient Of Performance ◽  
Total Power ◽  
Vapor Compression ◽  
Total Power Consumption ◽  
On Chip ◽  
The Individual ◽  
The Impact

Thermoelectric (TE) microcooling is promising for removing hotspots in integrated circuit chips. The cooling coefficient-of-performance (COP) of the on-chip thin film or superlattice micro-cooler (SLC) is a metric for assessing the energy efficiency of the hot spot removal. The COP is key for lowering total power consumption and minimizing heat sinking requirements. Due to the moderate performance compared to vapor compression cycles, researchers have devoted considerable effort to improving the figure-of-merit (ZT) of the material over the past decade. However, the impact of each of the individual thermoelectric properties has not been studied separately. We report our study based on an analytical model and analysis results that show the intrinsic impact of electrical conductivity, the Seebeck coefficient, and thermal conductivity, while the device thickness and the drive current are optimized for maximizing cooling COP. The results show that the power factor of the TE materials is a more important parameter than thermal conductivity reduction for improving the cooling performance of the on chip SLC.

scholarly journals Performance Study and Efficiency Improvement of Ice Slurry Production by Scraped-Surface Method

2018 ◽  
Vol 9 (1) ◽  
pp. 74 ◽  
Author(s):  
Xi Liu ◽  
Yueling Li ◽  
Kunyu Zhuang ◽  
Ruansong Fu ◽  
Shi Lin ◽  
...  
Keyword(s):  
Sodium Chloride ◽  
Power Consumption ◽  
Flow Rate ◽  
Coefficient Of Performance ◽  
Total Power ◽  
Solution Flow Rate ◽  
Ice Slurry ◽  
Solution Flow ◽  
Surface Method ◽  
Total Power Consumption

In this study, the performance of ice slurry production by scraped-surface method was experimentally investigated. Temperature change characteristics, ice packing fraction (IPF) of ice slurry, power consumption of scraping system and coefficient of performance (COP) were measured by varying the concentration of sodium chloride solution, scraping speed, and solution flow rate. The effect of nanosilica on efficiency of ice slurry production was also studied. The results showed that scraping power consumption accounted for only a small proportion (about 5%) of the total power consumption of the system. An increase in the concentration of sodium chloride caused a decrease in the IPF and a decrease in the COP of the system. With the solution flow rate at 1.3 m3/h and scraping speed at 13 rpm, the maximum COP (2.43) was obtained. Furthermore, the addition of nanosilica had a significant effect on improving the system COP.

scholarly journals An Economical and Precise Cooling Model and Its Application in a Single-Cylinder Diesel Engine

2021 ◽  
Vol 11 (15) ◽  
pp. 6749
Author(s):  
Zhifeng Xie ◽  
Ao Wang ◽  
Zhuoran Liu
Keyword(s):  
Diesel Engine ◽  
Cooling System ◽  
Combustion Engine ◽  
Electronic Control Unit ◽  
Total Power ◽  
Dynamical Characteristic ◽  
Water Jacket ◽  
Single Cylinder ◽  
Pump Speed ◽  
Total Power Consumption

The cooling system is an important subsystem of an internal combustion engine, which plays a vital role in the engine’s dynamical characteristic, the fuel economy, and emission output performance at each speed and load. This paper proposes an economical and precise model for an electric cooling system, including the modeling of engine heat rejection, water jacket temperature, and other parts of the cooling system. This model ensures that the engine operates precisely at the designated temperature and the total power consumption of the cooling system takes the minimum value at some power proportion of fan and pump. Speed maps for the cooling fan and pump at different speeds and loads of engine are predicted, which can be stored in the electronic control unit (ECU). This model was validated on a single-cylinder diesel engine, called the DK32. Furthermore, it was used to tune the temperature of the water jacket precisely. The results show that in the common use case, the electric cooling system can save the power of 255 W in contrast with the mechanical cooling system, which is about 1.9% of the engine’s power output. In addition, the validation results of the DK32 engine meet the non-road mobile machinery China-IV emission standards.

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