Re: Fw: Peeved at the pump

From: Al Koop <koopa@gvsu.edu>
Date: Sat May 15 2004 - 13:13:36 EDT

dennis@innovatia.com wrote;

>>>As an engineer into power electronics, I have been sudying energy
alternatives for the last few years, and this might be the occasion to
say something about the prospects.

[snip]

>>>4. Solar thermal: use a solar concentrator to heat a fluid stored in
an insulated tank as thermal energy. Besides nuclear and chemical
(ethanol in a tank) energy, this one has the highest energy density,
especially if state-change materials are used for heat storage. Then use
thermal-to-electrical converters.

>>>I am currently workng on a design for a Solar Thermal Electric System
(STES) because it looks quite promising an nobody seems to be doing it.
(I'm looking for a mechanical/chemical-oriented partner for this too.)
Here's why it is cheaper and better than solar PV. First, storing heat
in a tank is less costly and has less maintenance than storing charge in
a battery bank. Second, by separating energy collection from conversion,
the additional degree of freedom allows for optimizing system sizing,
which reduces cost.

Thanks for the energy alternatives update, Dennis. Since I am for the
most part a geneticist, I cannot figure out estimates for all the costs
and effciencies of these alternative energy devices.

It seems like we really need some way of storing electrical power (or
some easily converted energy source) somewhat inexpensively in a small
space at a high efficiency. Since we have electric golf carts and some
other electric vehicles, and since a power station up north of here
pumps water up to a reservoir at night and releases it during the day to
regenerate the electricity they expended during the night pumping the
water higher up, (with what must be some significant energy loses) we
obviously have have been workng on this problem a long time without
great success. It sure would be nice to be able to store a day's (or
preferably more) worth of electricity in some device for later use.
This would allow us to store energy as well from intermittent sources
like wind, solar and tides and also just from electrical-generating
plants at night when demand is low. If we had the capablitity of doing
that economically now, it seems like we would already be doing that. I
conclude that solving this problem must be difficult and maybe even
impossible. What is worrisome is that with all of these alternative
energy sources that have some promise, it is not obvious that we will
have these economically functional when fossil fuels are depleting since
they may well be difficult to develop also.

So how good are your solar-thermal devices, or how good could you
reasonably expect them to be in a few years? Is it possible now or
sometime in the near future to store a day's worth of power in a home to
run the lights, refrigerator. furnace, plus one other appliance at the
same time? How much space would the device take? How much would it
cost? What would its maintenence costs be? How long would it last?

Petroleum products are so convenient because you can store a lot of
energy in a small amount of space and utilize the stored energy
gradually in a somewhat efficient manner whenever you wish. It is not
clear to me that we are very close to duplicating those properties in
alternative energy sources.

Al Koop
Received on Sat May 15 13:14:24 2004

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