Panasonic Develops Thermoelectric Tubes for Compact
Geothermal Electricity Generation and Waste Heat Recovery
Panasonic opens up the way to generate electricity by harnessing thermal
energy in conventional hot water piping
Press Release
June 30, 2011
Osaka, Japan - Panasonic has developed innovative thermoelectric tubes especially suited
for fluid heat sources such as hot water and steam. The tubular shape enables direct
and efficient heat transfer without additional heat exchangers,
yielding high density of generated power. Panasonic’s thermoelectric tube with simple,
compact, and efficient features is an ideal solution for capturing unused or wasted
heat from hot springs and factory.
Thermoelectric technology is the direct energy conversion from heat into electricity and
has attracted much attention as a renewable energy solution. Since conventional thermoelectric
generators are complicated in structure and restricted in planarshape,
they are difficult to scale-up and implement. Panasonic’s thermoelectric tubes solve these
problems by using unconventional phenomena called transverse thermoelectric effect,
which takes place in tilted multilayer made of thermally-resistive thermoelectric
materials and thermally-conductive metals. This effect makes it possible to control heat flow
and electric current independently in materials, and realizes quite simple structure
without complicated electric junctions and planar substrates.
The performance of power generation is strongly dependent on many parameters suchas size of
the tube and amount of heat source. Panasonic has developed the simulation technology to optimize
the design of the thermoelectric tube in order to maximize the output electric power in accordance
with surrounding conditions.
Panasonic opens up the way to generate electricity by harnessing thermal energy in
conventional hot water piping. The 10 cm-long thermoelectric tube generates 1.3W of electricity
from hot running water of 90°C. Compact power stations, which are capable of generating 10 kW
with only 1m^3, will eventually be realized, fueled by hot springs as well as factory waste
heat distributed around the world.
The thermoelectric tube is constructed by stacking conical rings of bismuth tellurideas
thermoelectric material and nickel as metal. Panasonic has developed processing technologies
in fabricating conical rings of brittle thermoelectric materials and bonding rings with
minimum parasitic electric and thermal losses.
The 10cm-long fabricated thermoelectric tube using technologies introduced above can
generate 1.3 W of electricity by running hot water of 90 °C inside, and cold water of 10°C
outside the tube. The power density corresponds to as high as 10 kW with only 1 m3 of volume.
Development on system design, optimization in manufacturing and feasibility study are now under
way or planned, with a view to realizing compact, efficient, and economical generators fueled
by geothermal energy and waste heat in factories.
On this development, Panasonic holds 29 domestic patents and 12 overseas patents, including
pending applications.
This development was partially presented at Electronic Materials
Conference held in Santa Barbara,
United States on June 22, 2011.
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