143 research outputs found
A numerical study on the design trade-offs of a thin-film thermoelectric generator for large-area applications
Thin-film thermoelectric generators with a novel folding scheme are proposed
for large-area, low energy-density applications. Both the electrical current
and heat transfer are in the plane of the thermoelectric thin-film, yet the
heat transfer is across the plane of the module - similar to conventional bulk
thermoelectric modules. With such designs, the heat leakage through the module
itself can be minimized and the available temperature gradient maximized.
Different from the previously reported corrugated thermoelectric generators,
the proposed folding scheme enables high packing densities without compromising
the thermal contact area to the heat source and sink. The significance of
various thermal transport, or leakage, mechanisms in relation to power
production is demonstrated for different packing densities and thicknesses of
the module under heat sink-limited conditions. It is shown that the power
factor is more important than ZT for predicting the power output of such
thin-film devices. As very thin thermoelectric films are employed with modest
temperature gradients, high aspect-ratio elements are needed to meet the -
usually ignored - requirements of practical applications for the current. With
the design trade-offs considered, the proposed devices may enable the
exploitation of thermoelectric energy harvesting in new - large-area -
applications at reasonable cost.Comment: 26 pages,5 figures, post-peer-review, pre-copyedit version of an
article published in Renewable Energ
Exploitation of Transparent Conductive Oxides in the Implementation of a Window-Integrated Wireless Sensor Node
Exploitation of transparent conductive oxides (TCO) to implement an
energy-autonomous sensor node for a wireless sensor network (WSN) is studied
and a practical solution presented. In the practical implementations, flexible
and rigid substrates that is polyimide and glass, are coated with TCO, namely
aluminum doped zinc oxide (AZO). AZO-coated flexible substrates are used to
form thermoelectric generators (TEG) that produce electricity for the sensor
electronics of the node from thermal gradients on a window. As the second
solution to utilize AZO, its conductive properties are exploited to implement
transparent antennas for the sensor node. Antennas for a UHF RFID transponder
and the Bluetooth radio of the node are implemented. A prototype of a flexible
transparent TEG, with the area of 67 cm2 when folded, was measured to produce
power of 1.6 uW with a temperature difference of 43 K. A radiation efficiency
of -9.1 dB was measured for the transparent RFID antenna prototype with the
center frequency of 900 MHz. Radiation efficiencies between -3.8 dB and -0.4
dB, depending on the substrate, were obtained for the 2.45 GHz Bluetooth
antenna.Comment: 10 pages, 14 figures, last author version accepted for publication in
IEEE Sensors Journa
Spectrum, Volume 13, Number 3
Highlights include: WWPT will soon be transmitting a low power, on campus only, radio wave which can run continuously for 24 hours. WWPT currently broadcasts on 90.3. The new frequency is likely to be 91.5 pending further testing --Opening soon in former room SI 10, next to the radio station, is The Marche, which will offer a variety of grill and fast food items --The GE Scholar Program consists of students from a wide variety of ethnic backgrounds, many of whom are commuter students. Each scholar is awarded $2,000 per year and each participant in turn, contributes to the community --After seeing limited time in the Pioneer back field last season behind four-year starter Ron Stopkoski, Brian Ihlefeld has arrived as a strong and elusive runner this season as well as a big play maker for the SHU gridders --The varsity crews have their first competition this Sunday in Mystic, CT, where they will compete in the Great Pawcktuck Paddle or Row Race --The men’s soccer team is on a tear after winning 4 in a row --Women’s field hockey team has increased the win column to 4-1 with their recent victories over Manhattenville, Albany and Keene State
Nano-thermoelectric infrared bolometers
Infrared (IR) radiation detectors are used in numerous applications from
thermal imaging to spectroscopic gas sensing. Obtaining high speed and
sensitivity, low-power operation and cost-effectiveness with a single
technology remains to be a challenge in the field of IR sensors. By combining
nano-thermoelectric transduction and nanomembrane photonic absorbers, we
demonstrate uncooled IR bolometer technology that is material-compatible with
large-scale CMOS fabrication and provides fast and high sensitivity response to
long-wavelength IR (LWIR) around 10 m. The fast operation speed stems from
the low heat capacity metal layer grid absorber connecting the sub-100 nm-thick
n- and p-type Si nano-thermoelectric support beams, which convert the radiation
induced temperature rise into voltage. The nano-thermoelectric
transducer-support approach benefits from enhanced phonon surface scattering in
the beams leading to reduction in thermal conductivity, which enhances the
sensitivity. We demonstrate different size nano-thermoelectric bolometric
photodetector pixels with LWIR responsitivities, specific detectivities and
time constants in the ranges 179-2930 V/W, 0.15-3.1 cmHz/W
and 66-3600 s, respectively. We benchmark the technology against different
LWIR detector solutions and show how nano-thermoelectric detector technology
can reach the fundamental sensitivity limits posed by phonon and photon thermal
fluctuation noise.Comment: 20 pages, 4 figures, 1 tabl
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