This does not sound too practical,
but it reminds us that protocols do exist for pigs that at least that takes
advantage of the ammonia through bacterial activity in a deep bed of wood
shavings. That does clean up the air
inside the barns. Such material is
steadily reduced until it is suitable as soil additive. I would go further and actually carbonize the
spent bedding material.
A practical air to air heat
exchange has long been desired, but efficiency is a real problem as the
thermodynamic gradient is rather small to start with. The best I have ever heard of was an attempt
to devise a rotary separator that split hot from slower cold gases in a gas
stream to produce a cold and warm output flow.
In winter, the warm flow can be reblended with the incoming airflow
while the opposite can be done in summer.
Sounds good, but practicality needs to be demonstrated. The challenge is to get it to work well
without using a secondary source of compressed air.
In some respects, this is a
solved problem whose solution has never been universally implemented. In agriculture there are many such situations
as there are in industrial process. A
global solution has to be established such as occurred to end the problem of released
refrigerants. Otherwise, the added cost
is enough to allow profiteering to occur at the expense of the compliant.
Prototype system removes air pollutants and generates heat for
livestock barns
By Ben
Coxworth
18:20 January 5, 2012
A prototype system has been created for cleaning and heating the air in
chicken and swine barns (Pig barn via Shutterstock)
If you've ever so much as stepped into a chicken or swine barn, you'll
know that they can be very, very smelly places. When vented outdoors, the air
from these buildings does more than just make the area stink - it can actually
be a major source of air pollution and greenhouse gases. Fortunately, however,
researchers from North Carolina State University and West Virginia University
have created a system that not only helps clean the air going out of the barns,
but it heats up the air coming in from outside.
The system runs the polluted air through a biofiltration medium, such
as compost or wood chips. Bacteria living within that material break down and
neutralize the pollutants, much as they do in biofilters used for fish ponds or
aquariums. Once it's time to replace the medium, the old material can be used
as crop fertilizer, as it is full of valuable nitrogen.
The use of such a filtration system would increase costs for farmers on
its own, so the researchers are hoping to offset those costs by allowing the
system to assist in heating incoming air. This is done using a heat
exchanger, which receives heat from both the warm, polluted air that is being
treated, and from the biochemical reactions taking place within the biofilter.
So far the team has focused on the removal of ammonia, as it is very
plentiful in such barns, and is a major source of pollution. When a prototype
system was tested on a 5,000-bird chicken barn, it was found to remove up to 79
percent of the ammonia from the outgoing air, and recovered up to 8.3 kilowatts
of heat.
"The technology is best suited for use when an operation wants to
vent a facility that has high ammonia concentrations, and pump in cleaner air
in preparation for a fresh batch of chicks or piglets - particularly in cold
weather" said NC State's Dr. Sanjay Shah. "It is also suitable for
use when supplemental heat is required for raising the young animals."
A paper on the research was recently published in the journal Applied Engineering in Agriculture.
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