RE: GAS-L: Wasted heat retrieval to electrical power

[Weststeijn A <A.Weststeijn@epz.nl>]

Hi Peter,

> Peter Singfield[SMTP:snkm@btl.net]
> maandag 19 februari 2001 0:33
> 
> 
> Folks;
> Waste heat retrieval is all about delta T's - that is difference between
> top temperature and lower temperature.
> Just how small can that be??
> Well -- the Japanese are planning some big projects working with a delta T
> of just 18 degrees C.
> Guess they have more of an eye to the future than fossil fuel dependent
> countries that believe the present situation can go on for ever and one
> day.
> 
Peter, a temperature difference of 18 degrees C doesn't say much in itself
(we remove hundreds of MegaWatts-thermal at low temperatur with only 7
degrees C difference).
However, it is all in the cost of the equipment required to extract the
heat, as well as in the duct/pipe sizing and pumping capacities of the heat
removal agent.

If a low delta T, then the sizes and pumping capacities go up. From there it
follows whether the concept is financially feasible or not. Simple. No black
magic.
One tends to keep delta T's up to keep investment and operating costs down,
but that is no particular accomplishment in itself.

About Japan:
could it be that the cost of thermal energy for distric heating and cooling
is relatively high in Japan, so as to allow for more costly waste heat
systems to be installed?

best regards,
Andries