Hybrid Car – More Fun with Less Gas

Greenhouse size to evaporate 330 gallons ?

register ::  Login Password  :: Lost Password?
Posted by EdRogers on March 16, 2009, 6:43 pm

If a greywater greenhouse  in Massachusetts needs to evaporate 330
gallons per day (assume compost toilet not connected to it, zero
discharge)    A legal, piloted title 5  alternative septic system
How big would it have to be?, How much insulation on the north, shady
side, and under slab?

This greenhouse would be similar to the units of David Del porto
and Dr. John Todd http://www.toddecological.com/eco-machines/  for
waste water treament.
Thanks in advance for your help


Posted by andrew on March 16, 2009, 8:54 pm
EdRogers wrote:

The difference between the enthalpy of the liquid and the vapour is about
800kWhrs(t), so that's the minimum heat required input for a 100% efficient


Posted by nicksanspam on March 18, 2009, 11:09 am

Or less, with multiple effects. Conceptually, imagine a stack of
transparent trays with liquid on top and condensaton below. Sun
shines in the top and the heat of condensation is reused...


Posted by daestrom on March 18, 2009, 9:12 pm

Yep, a 'double-effect' or 'triple-effect' distilling unit does just that.

But it's not clear from the OP that he wants to condense the vapor back
again.  He may just be trying to 'dry' something.

And of course *some* of the energy for evaporation could be taken from the
surrounding atmosphere.  Just blowing air across the surface will do a lot
for speeding the drying process (if that's the goal).


Posted by EdRogers on March 22, 2009, 4:24 pm
Hello all,

If I could add a little more detail.. , the greenhouse   calculations/
design help I need is for a mostly  solar heated greenhouse, a
greywater  greenhouse is allowed in MA if you use a compost toilet,
In MA a greenhouse is needed due to winter, where other areas can get
away with just out door drip gardens for the greywater. We are trying
to save a hay field for a farmer to use and the only option is to go
compost/greywater due to ledge at non-field site.   The only info I
have says approx .20 gal/sqft/day which would be a huge structure.
This technique is termed evapotranspiration  uses plants to
biologically treat waste, and evaporate the water,  this being a
voluntary system for us.  We happen to have a large qty of glass from
a mall demo.  I hope to see btu /sqft calcs for solar greenhouses,
super insulated all but south
side?  Is heat of vaporization involved? 1072 btu per pound?,   Winter
is the tough time, can an air to air heat exchanger be designed , To
use the dry winter air to remove the moist air from the greenhouse?
But still retain the heat for the plants?  Auxiliary heating would be
supplied by the house  generator , it will sit inside the  greenhouse
as its shed,  12hp listeroid, for the house radiant slab, and battery
charging, but its block should dump a fair amount of heat into the
greenhouse no?  the text talk about plant et rates etc. but I m
looking for btu/ pounds of water/ r values etc  typical for this
newsgroup, been reading for years.

Thanks for any and all comments





This Thread
Bookmark this thread:
  • Subject
  • Author
  • Date
please rate this thread