Yes, the cost is high! I think I figured the cost of a set of junctions from TE on the net at $150 us for 6 amps at 15 volts, using a temp difference of 200c.. Lower temp difference will be much higher. You can find all the data on the TE website to do the calculations. Using a evacuated tube solar collector as heat source temps of 300 deg F. temps are possible, and with a water sink (pumping water from a deep keel not the surface) would help reduce the number of units needed. If however you loose your cooling water flow catastrophe failure is a sure bet.
On the positive side such a system can be run 24/7 should you devote space for a heat battery that will supply enough heat to run through the night. As an alternative, fuel oil will supply the heat needed on cloudy days.
The catch for such a system is the roughly 95% loss to inefficiency. If you have plenty of collector space the energy losses mean little, and it is accepted that a square meter of surface area receives 1000w of heat energy from the sun, even 50% recovery of heat is considered good making 500 watts realistic.
Lower losses have been realized with a solar heat engine (stirling engine), however life expectancy for a well designed system may point you in the direction of the pelter junctions over the stirling engine. Both techs work with a any heat differential however and have been studied for many years. Deep space probes use the stirling engine with a nuclear heat source, go figure. My small proto-type using solar uses Pelter Junctions and I feel the daily output is better than any PV on the market even though the efficiency rating of some panels are better than 50%. The reason is I have 250 square feet of collector surface with a large heat battery. Solar heat collectors are much cheaper than PV of any style so there you have it.
Kevin Pemberton
On 08/10/2010 03:23 PM, Ron wrote:
Hi Bill,
As Lonner said, the price will be the killer, we used these in some applications when I worked in a wafer fab. I have not checked prices after 2000 but they were high back then.
Ron
--- In electricboats@yahoogroups.com, William Grace <jwsys@...> wrote:
>
> Hi Ron
>
> Your concept of using the wasted heat from anywhere has got me thinking.
>
> If I remember my physics correctly, pairs of thermocouples can provide
> this result. Solid state chiller boxes use this principle in reverse
> (refrigerators without compressors). These thermocouples consist of
> dis-similar metals connected electrically, and are used in pairs. In
> the chiller set up, one of the thermocouple joints is inside the box
> whilst the other is outside. The thermocouples are connected in
> series and are then connected to a battery of suitable voltage. The
> current flowing through the series system causes the joint temperature
> to change, one becoming hotter, the other colder. Most of the simple
> chiller boxes have a 'heat' option which is derived by reversing the
> connections. Theoretically, it is possible to reverse the process
> so that a current is produced when the thermocouples are held at
> different temperatures. One could be under a solar panel whilst the
> other half of the pair could be attached to a skin fitting which would
> hold it at water temperature. The parts could be obtained by
> disassembling a chiller box. Usually the thermocouples are attached
> to heat sinks, one being placed inside the box with the other outside.
>
> I have not tried this but expect it would work although the current
> generated would be of a similar order to that used to run the chiller.
>
> Bill Grace
> NZ
>
-- Ubuntu10.04, Acer AspireOne, Virgin Mobile 3G Broadband2go. Doesn't get any better than this!
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