Hot composting dilema

sonya_2007

18 years ago

Hi, Hope someone can help i have an unusual question concerning composting.

I am trying to set up a hot compost heap and am using old wheelie bins (240 litre wheeled plastic trash cans)I have to somehow insulate the wheelie bins and thought that a reflective foil insulation like thermawrap might do the trick. So that would be thermawrap inside/ outside the bin?

I know that I could use wood or buy a compost bin but this is for a masters university project here in Ireland concerning the extraction of heat from compost for use in greenhouses. I will not bore you anymore but although I know that a different system might be better I need to use this system initially. I would be very grateful for some suggestions on how best to insulate the compost bin to encourage hot composting.

Would this work or is a complete waste of time and money.

Hope someone can help.

Thanks,

Sonya

Sort by:Oldest

Comments (5)

pablo_nh
18 years ago
On the contrary- many here are really interested in use of compost heap (I've used it as a very makeshift hot frame in the spring).

Your setup, at least as described, may run into a couple of basic issues- first- wrapping it up like that will limit oxygen. No oxygen- no heat. If you are trying to extract heat and send it someplace, then you may try perforated pvc pipes through the bottom of the container, al the way through the compost bed, out the top to provide aeration. The bin should be raised a little to allow air in the bottom holes.

Second- to get maximum heat, and to get it to last- you want a good volume of compost (at least 1 cubic meter per pile) in each pile. This is generally based on the surface area to volume ratio of the pile: a larger pile has a smaller surface area for cooling relative to the volume producing the heat. Also- heat at the center of the pile is higher because of the contribution of the heat in the bulk (more bulk- more heat delivered to the thermophiles in the middle). Larger bins, or putting them touching together will help here. Smaller bins will not only produce less peak temperature, but they will stay warm for less time as the compostables are consumed.

Your reflective blanket should help this, also. The blanket should go on the inside of the bin, or at least face inwards wrapped around the bin. The outside should be painted a dark color to allow for absorbtion of stray IR from outside; we normally say that the heat is from microbes rather than the sun, but since you are literally using the pile to do work (in the physics sense), you will maximize heat production this way.
pablo_nh
18 years ago
"On the contrary- many here are really interested in use of compost heap"

Compost HEAT... HEAT, not heap...
Related Professionals
South Orange Landscape Architects & Landscape Designers · Aurora Landscape Contractors · Downey Landscape Contractors · Edinburg Landscape Contractors · Fruit Heights Landscape Contractors · Kerman Landscape Contractors · Mendota Heights Landscape Contractors · Norwalk Landscape Contractors · Peoria Landscape Contractors · Teaneck Landscape Contractors · Centreville Decks, Patios & Outdoor Enclosures · Dracut Decks, Patios & Outdoor Enclosures · Greendale Decks, Patios & Outdoor Enclosures · Jeffersonville Decks, Patios & Outdoor Enclosures · Lewisville Decks, Patios & Outdoor Enclosures
ixnod
18 years ago
pablo you said that the wrap should go on the inside of the bin would the material effect the compost or vice versa ( the material begining to become part of the compost)?
pablo_nh
18 years ago
Naw- it's a polymer- it should hold up very well.
squeeze
18 years ago
unless you're dealing with extreme cold for extended periods, insulation won't be worth the trouble .... and as Pablo sez, the volume of your 240L carts won't suffice to maintain heat for any useful length of time, and if the totes you have are relatively tall and narrow, the air circulation problem is a major consideration

Bill