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<DIV><STRONG><FONT size=2 face="Courier New">RT wrote:<BR><BR>> In
winter... the dryer is vented indoors...<BR><BR>> The excess moisture
and lint is dealt with by directing the exhaust into<BR>> a bell jar-like
receptacle made out of recycled 1,2 and 4 litre yoghurt,<BR>> tofu and ice
cream tubs.<BR>><BR>> The tubs are configured so that the vapour condenses
out of the exhaust...<BR><BR>This could help heat a house in wintertime... The
tubs are filled with water?<BR>Condensing 12,000 Btu (3.5 kWh) from a 12 lb load
of towels which contain<BR>an extra 12 pounds of water after washing and
spinning, with a 10 F temp rise<BR>(eg 70 to 80 F) would require 12000/10 = 1200
pounds or 545 liters of water</FONT></STRONG></DIV>
<DIV><STRONG><FONT size=2 face="Courier New">in an unstratified bell-jar-like
receptacle. </FONT></STRONG></DIV>
<DIV><STRONG><FONT size=2 face="Courier New"></FONT></STRONG> </DIV>
<DIV><STRONG><FONT size=2 face="Courier New">Stratification could help. If the
dryer exhaust is 130 F, 5 C Btu/F containers</FONT></STRONG></DIV>
<DIV><STRONG><FONT size=2 face="Courier New">in series might end up
a</FONT></STRONG><STRONG><FONT size=2 face="Courier New">t 120, 110, 100, 90,
and 80 F. The first could store</FONT></STRONG></DIV>
<DIV><STRONG><FONT size=2 face="Courier New">(120-70)C = 50C Btu, the second
could store 40C... and whole collection could </FONT></STRONG></DIV>
<DIV><STRONG><FONT size=2 face="Courier New">store </FONT></STRONG><STRONG><FONT
size=2 face="Courier New">150C, so C = 12K/150 = 80, with a total of 5x80 =
400 pounds of water, </FONT></STRONG></DIV>
<DIV><STRONG><FONT size=2 face="Courier New">eg 182 2-liter bottles, eg 37
vertical bottles in a hex pattern, with 4 more</FONT></STRONG></DIV>
<DIV><STRONG><FONT size=2 face="Courier New">layers of 37 above that, in a
sqrt(0.91x(4/12)^2x37) = 2' square x 5' tall</FONT></STRONG></DIV>
<DIV><STRONG><FONT size=2 face="Courier New">tube with baffles to help with
stratification.</FONT></STRONG></DIV><STRONG><FONT size=2
face="Courier New"></FONT></STRONG><STRONG><FONT size=2 face="Courier New">
<DIV><BR>We might warm 70 F room air at 50% RH up to a 130 F dryer temp with a
small</DIV>
<DIV>fraction of the 12K Btu, if we don't rehydrate the room
air...<BR><BR>Can we cool the hot dryer output (130 F at 100%
RH?) to 80 F at 100% RH,</DIV>
<DIV>then use the resulting heat to rewarm the 80 F air to 130 F at a lower
RH</DIV>
<DIV>and circulate it through the dryer at 130 F until its RH rises to
100%?<BR></DIV></FONT></STRONG>
<DIV><STRONG><FONT size=2 face="Courier New">Steven Tjiang (KZ6LSD)
wrote:<BR></FONT></STRONG></DIV>
<DIV><STRONG><FONT size=2 face="Courier New">>Such a dryer is commercially
available. The principle is as you describe though</FONT></STRONG></DIV>
<DIV><STRONG><FONT size=2 face="Courier New">the numbers are certainly
different. It's called a condensing dryer. See </FONT></STRONG><A
href="http://goo.gl/kMpK"><STRONG><FONT size=2
face="Courier New">http://goo.gl/kMpK</FONT></STRONG></A></DIV>
<DIV><STRONG><FONT size=2 face="Courier New"></FONT></STRONG> </DIV>
<DIV><STRONG><FONT size=2 face="Courier New">It looks like that dryer works
like RT's. It's more efficient than a conventional
dryer which</FONT></STRONG></DIV>
<DIV><STRONG><FONT size=2 face="Courier New">exhausts hot moist air
</FONT></STRONG><STRONG><FONT size=2 face="Courier New">to the outdoors,
since all the heat ends up in the house and the house</FONT></STRONG></DIV>
<DIV><STRONG><FONT size=2 face="Courier New">does not have to warm up any
</FONT></STRONG><STRONG><FONT size=2 face="Courier New">cold
</FONT></STRONG><STRONG><FONT size=2 face="Courier New">incoming air in
wintertime, but it still uses about 3.5 kWh</FONT></STRONG></DIV>
<DIV><STRONG><FONT size=2 face="Courier New">of electrical energy to evaporate
</FONT></STRONG><STRONG><FONT size=2 face="Courier New">12 lb
</FONT></STRONG><STRONG><FONT size=2 face="Courier New">of water from clothes,
and that energy is not useful</FONT></STRONG></DIV>
<DIV><STRONG><FONT size=2 face="Courier New">in </FONT></STRONG><STRONG><FONT
size=2 face="Courier New">summertime. (Altho it's more efficient than a
water-cooled condensing dryer with no </FONT></STRONG><STRONG><FONT
size=2 face="Courier New">useful</FONT></STRONG></DIV>
<DIV><STRONG><FONT size=2 face="Courier New">wintertime
heat.) </FONT></STRONG></DIV>
<DIV><STRONG><FONT size=2 face="Courier New"> </FONT></STRONG></DIV>
<DIV><STRONG><FONT size=2 face="Courier New">Suppose we put the 5 groups of
containers above into a well-insulated tube A and make
another</FONT></STRONG></DIV>
<DIV><STRONG><FONT size=2 face="Courier New">tube B just like A, and connect the
dryer exhaust </FONT></STRONG><STRONG><FONT size=2 face="Courier New">to one end
of tube A, and the output of A</FONT></STRONG></DIV>
<DIV><STRONG><FONT size=2 face="Courier New">into tube B and the output of B to
the dryer inlet. On the next load, we swap A and B...</FONT></STRONG></DIV>
<DIV><STRONG><FONT size=2 face="Courier New"></FONT></STRONG> </DIV>
<DIV><STRONG><FONT size=2 face="Courier New">Like this:</FONT></STRONG></DIV>
<DIV><STRONG><FONT size=2
face="Courier New">
--------------------------</FONT></STRONG></DIV>
<DIV><STRONG><FONT size=2
face="Courier New"> ---------------->------|---------X---<>| 120
110 100 90 80
|<>---</FONT></STRONG></DIV>
<DIV><STRONG><FONT size=2
face="Courier New">|
|
output |
-------------------------- |</FONT></STRONG></DIV>
<DIV><STRONG><FONT size=2 face="Courier New"><STRONG><FONT size=2
face="Courier New">|
</FONT></STRONG><STRONG><FONT size=2
face="Courier New">|
|
A
| </FONT></STRONG></DIV>
<DIV>
<DIV><STRONG><FONT size=2 face="Courier New">| dryer
|
|
|</FONT></STRONG></DIV>
<DIV><STRONG><FONT size=2 face="Courier New">
<DIV><STRONG><FONT size=2
face="Courier New">|
|
|
B
|</FONT></STRONG></DIV>
<DIV><STRONG><FONT size=2
face="Courier New">|
| input
|
--------------------------
|</FONT></STRONG></DIV><STRONG><FONT size=2 face="Courier New">
<DIV><STRONG><FONT size=2
face="Courier New"> ----------------<------X---------|---<>| 120
110 100 90
80 |<>---</FONT></STRONG></DIV>
<DIV>
--------------------------<BR></DIV>
<DIV>At an average 100 F in a 4'x7'x7'-tall box with 210 ft^2 of
R40 walls and a 5.25 Btu/h-F</DIV>
<DIV>conductance, the tubes might lose 24h(100-70)5.25 = 3780 Btu/day.</DIV>
<DIV> </FONT></STRONG></FONT></STRONG></DIV>
<DIV>Is there a better way? In principle, clothes drying shouldn't require
any energy, if we</DIV>
<DIV>reuse the heat, as in the combined cycle power
generation in some old steam locomotives</DIV>
<DIV>or the 8-effect dehumidification achieved in a 1975 solar still
in the Sonoran desert.</DIV>
<DIV> </DIV>
<DIV>Nick</FONT></STRONG></DIV></DIV></DIV></BODY></HTML>