HOT GRASS.

[Jerry]

I live on one acre. About 1/3 of that is lawn. I have a riding mower. I use to rake all that grass. I got very tierd of that. I bought one of those power vacs you connect to your mower. It holds alot of grass.

I've been busy and had left a half load of grass in this thing for several days.

I live 1 mile from the dumo. So I just pull it over there with my PU.

I noticed today while unloading this mass of grass its heat. Very hot....maybe 90% or more.

So I'm thinking? why not build a box with some copper coils in it dump the grass over the coils and pass some watter through.

I think it would heat the watter quite abit? Maybe usefull?

                       JK TAS Jerry

[windstuffnow]

   I've thought of doing something similar using damp hay.   You've heard of people's barns burning down because the put back a bundle of wet hay.   A nice chemical reaction.   I'd bet you could make lots of heat.

   I mow 5 acres every 2 weeks or so and could end up with enough to make a nice slurry for methane as well.  

   Great idea!

.

[K3CZ]

Gents:

Here you are rediscovering early (read stone age) technology as to why hay must be cured (dried in the sun) before it is stored in bulk. (The reaction can proceed with many other fermenting agents as well - wadded up oily rags used to be notorious for starting unwanted fires)  It can indeed be put to useful work as part of a methane producing and digesting system that will consume most any kind of biomass.  Many old landfills are being tapped for sellable methane fuel these days. However, large closed containers capable of withstanding considerable pressure are involved if home production is attempted.  BTW, we are talking tons of material here to make it work on a practical basis.  There are dairy farms (large ones - 500+ animals) that can (and are) produce enuf methane from farm waste products to run an IC engine that will produce enuf electricity for the whole farm facility, and sell some back to the utility, besides!                          Van     K3CZ

[whatsnext]

I'm pretty sure that if you did this you would remove enough heat to stop, or at least slow, the reaction and there goes your source of heat. If you could let the cut grass sit for a couple of days it might make a pretty good fuel for a pellet stove once pelletized.

[DanG]

whatsnext hit it - heat of sugars and starches being broken down are amplifed & microbial activity increased from organic chemistries occuring faster at higher temps. As temperatures pass certain points different families of microbes bloom, each wave filling its niche in the compost cycle. If temperature rise stalls in the 'thermal mass' it can block any further breakdown, one niche organism overpopulates and poisons the compost media so strongly the next 'niche' organism is suppresed.

Here in Minnesota we have 10 weeks in summer where you can make black dirt compost - sometimes taking 7 to 10 days start-to-finish to digest even the cellulose in leaves and grass clippings. Otherwise cool ground and air temps stall out compost cycle, even if you water with sugar water and add nitrogen fertilizers, leaving stuff a "dry rotted" fluff full of mychorizia (?) fungal stuff.

If you kept the mass high enough and the media well stirred, w/ constant new waste being added and the oldest media being removed, it could boost water temps in a tempering tank (etc.) but it would be very labor intensive. Automated processes required as people don't much like to face that stuff intimately on a daily basis..

I think the wood-by-product co-generation plants in scandanavia get some heat out of fermenting the huge bulk of wood chips used, if only to help dry them out some before being fed into steam boilers...

[rotornuts]

Just a slight recap. As micro-organisms metabolize the organic materials they produce heat. The higher the nitrogen content of the materials the higher the heat and the faster the burnout.

A copper coil to remove the heat can actually benefit the process by helping to control the heat preventing the pile from getting too hot. If your compost gets above 65 degrees celcius it kills all the microbial life and the pile dies untill it is repopulated. Within a matter of days a compost pile can reach the thermophillic stage where excess tempature can be a problem.

Good compost piles control temature by mixing high carbon items such as leaves with high nitrogen items such as grass. I don't remember exactly but I believe it a 70% carbon to 30% nitrogen mixture by wieght or volume? Mixing or turning the pile can control heat  and is neccessary to keep the reaction going as it introduces less digested materials from the outer portions of the pile and introduces oxygen to prevent the pile from going anerobic.

If you makethe pile the right size and get the proper mixture going you could capture quite a bit of heat before it moves back into the mesophillic stage where little heat is produced.

Be prepared for alot of experimentation.

BTW, this is how gardeners used to apply bottom heat for propagating  and area heat in green houses.

Mike

[thunderhead]

The man to Google for is Jean Pain.

http://journeytoforever.org/biofuel_library/methane_pain.html

http://www.motherearthnews.com/library/1980_March_April/The_Genius_of_Jean_Pain

[Kwazai]

http://www.motherearthnews.com/library/1981_July_August/Compost_Heated_Water_

this one is probably a little closer to reality- the last one I could find that they built-complete with data. It will need a good source of nitrogen (fertilizer or urine(green grass?)).

[DanG]

The underline following the Compost heated water link is part of link, scoop forum omits it - copy and paste link, then add the ""  

http://www.motherearthnews.com/library/1981_July_August/Compost_Heated_Water

Good find!

[Kwazai]

I read some of the jean pain articles too, from what I could gather from it he was using the functional equivalent of sawdust in the woodgas generator by maintaining a 98F temp in the center-seems the pile would overheat without some watercooling. I'm not real sure whether he was relying on microbes or the charcoal process to generate the woodgas. The biggest part of his compost pile was functioning as insulation. I did some digging on hay fires- it should make a pretty good heater too. 4ft x 4ft x 4ft tall with bales, 40% relative humidity(soaking wet) and let it cook, if its not hot enough throw some air to it. Most of the info was related to not letting the hay get hot (so where are the free range basement cows when ya need em....)

L8r

Mike

[Ungrounded Lightning Rod]

I note that the compost piles were covered with black plastic to add some solar collection.

Given the size of the heaps and their surface area, I wonder how much of the heat harvested was actually from the compost and how much was solar.

Given how simple it is to build a solar collector, how it never runs out of compost, and how much land area is taken up by the compost heap, I might be inclined to go with just the collector and skip the heap.

Of course the facts that:

 - one of my sites has little land area and

 - the other is in a high desert where I don't plan to clear the brush and mostly need cooling anyhow

might have something to do with my bias.  B-)

[Norm]

   BTW ....couple years back bagged up grass

clippings and was going to haul them over to the

city composting facility...but they were closed

...so I left them overnight in the '89 Astrovan

....the next day the inside windows were steamed

up...bad organic smell...and the roof lining had

come unglued !

             Never Do This ! LOL

                    ( :>O Norm.