Hybrid Thermo-Electric Solar
This technology is virtually identical to
"Thermo-electric-solar" except that collection
capacity is slightly enlarged and the surplus heat is used for
DHW (domestic hot water) and/or space heating. Some space
heating requirement and DHW requirement can possibly be met by
waste heat from the heat-electric conversion as well. To
understand more about basic thermal-electric
solar visit this page.
The element of this technology that is hybrid is
the energy storage. Most likely a standard thermo-electric
system will have a large insulated holding tank with hot oil in
it. This tank will likely be at a temperature between 170 C and
200 C. Heat can be drawn from this reservoir by simply
circulating water through a coiled pipe placed within the tank.
By circulating water with a pump through this coil called a,
"heat exchanger", water can easily be heated to the 60
C point necessary for DHW. Likewise, if a baseboard or floor
heating water system is installed in a house, water can be
pumped through an additional heat exchange to bring the space
heating water temperature to 95 C. These uses will take heat
away from the reserve for electric generation, but makes for a
very nicely integrated hybrid system.
Waste heat from the electricity generation
component may also be used for some DHW or space heating. If
space heating is used or even if DHW is used where the DHW water
holding tank is nearly depleted frequently, The heat generated
on the cool side of the electricity generation system can be
used to bring the space heating medium or cold water part way to
operation temperature. Using waste energy from one process to
meet a different energy need is referred to as cogeneration.
Cogeneration can go a long way toward making a system much more
cost effective to operation and build.
It works like this. The cold side of the engine used to
generate electricity needs to be cooled to keep the energy generation
efficient. So either the cold side of a stirling engine, or the cold side
of a TEG device needs to have heat taken away and dispersed to the air.
This might take the form of a heat sink in which cool water is circulated.
That water is cooled by a radiator with a fan. The cogeneration approach
would be to provide an additional cooling option that would bring the
water in a space heating boiler from room temp to say 60% of its operation
temperature. The is needed whenever the boiler has not been in operation
for an hour or more. This initial heating phase uses a lot of energy, so
the cogeneration is very effective at reducing the overall energy need for
Another example of cogeneration might be to coil PEX
tubing or copper tubing in or under sidewalks and driveways on shaded
sides of buildings. Assuming you are in a climate where it snows or
freezes, waste heat from your electricity generation can heat these large
areas and melt snow. Swimming pool heating is another possible use for
The conclusion is this. If you have a thermal-electric
solar system you have two possible sources of heat for other uses. Those
heat sources are the hot storage tank and the cool side of your electrical
generation engine. The heat tank has high temp heat but using it costs you
electrical capacity. The cool side of your engine has lower temp heat, but
lots of it and it costs you nothing in terms of electrical capacity. The
more uses you can come up with for the lower temp heat, the higher overall
efficiency your system will have.