Aquaponics for the Frozen Tundra
I heard a rumor that Maximum Yield
readers like a challenge. So let me
throw down a gauntlet. I challenge you
to build an aquaponic system (fish and
plants together) that meets the following criteria:
• Provides space for 150 plants at
8-in. spacing
• Holds 100 fish at 2-lb. each
• Allows you to grow outdoors
• Handles nighttime temperatures
of -25°F
• Uses less than 1,400 kWh of
electricity annually, and no
other fuel sources
• Costs less than $4,000 to build
Sound impossible? Over the next
three issues, I will walk you through
four design strategies that make it
possible to grow outdoors when it’s
cold enough to freeze your pecans
off. This month
we talk about
my Winter
Aquaponics
Design Strategy
No. 1. In the
immortal words of
The Offspring, you’ve got
to keep ’em separated.
Your Fish Factory
The inspiration for this
design came from heavy
industry. As an engineer
working with energy
efficiency in factories,
I noticed something
striking—factories
Jeremiah’s snow-covered greenhouse.
are not like houses. In houses we heat
air. Because we move from one room to
another and want to stay comfortable
everywhere we go, we keep our whole
house warm. This generally requires
heating the air in the house above a
certain set point, say 68°F.
On the other hand, factories only
heat the things that need heating, and
they keep those things as separated
from the rest of the factory as possible.
For example, I visited a paper factory
in Wisconsin with a process that
requires heating a chemical solution
to 4,000°F. A few feet away, another
process requires cooling another
material down to 50°F. Keeping these
processes thermally separated required
some serious engineering.
Most people who grow using aquaponics outdoors in the cold (usually in a
greenhouse) treat their system like a
house—they heat the air. But when
you really get down to it, aquaponics is
more like a factory than a house.
Thermal Zones
In my Aquaponics Zones diagram
(below), you can see all the different
factory processes involved in aquaponics. I call them thermal zones. I’ll
tell you about each of them and their
requirements, and then we’ll learn
how to separate them thermally.
Fish Zone: The fish live here, in the
water. The requirements depend on
the type of fish. With the fastest-growing kind of fish—red Nile tilapia—this
zone should stay at above 80°F for
maximum growth. For other kinds of
fish, temperatures vary greatly. For
example, Arctic char find their happy
place around 40°F.
“when you really
get down to it,
aquaponics is
more like a factory
than a house.”
The different thermal
zones in an aquaponic system.
144
Maximum Yield USA | January 2015