Designing an Aquaponic Greenhouse for an Urban Food

(Mack, 2014)

Table 2. A comparison of different insulation material

2.3.1.6 Ventilation Systems
Greenhouse ventilation is the cycle of removing the air from inside of the greenhouse and replacing it
with the outside air. The main purposes of ventilation in a greenhouse are to control the high
temperature during the summer, to preserve the humidity at adequate levels during the winter, to
provide a uniform air circulation in the entire greenhouse. Ventilation not only maintains the
environmental conditions inside the greenhouse, but also influences the plant’s capability to perform
photosynthesis, absorb indispensable elements, and complete the pollination. (Dennis E. Buffington,
n.d.) (Hopper, 2012).

The absence of air circulation in the greenhouse harms the plants and also harms the structure of the
greenhouse. The problems associated with over condensation in greenhouses are fungus diseases and
difficulties in keeping the building clean. These issues cause a more rapid deterioration of the building,
and uncomfortable environmental conditions for the workers. A greenhouse without proper ventilation
would not only increase the costs of repairing it, but it would also increase the need for constant
maintenance, thus it will end up costing more to pay somebody to clean it. (Dennis E. Buffington, n.d.)

When analyzing the necessary ventilation, it is necessary to consider how the temperature varies during
the year. Summer ventilation is a way to keep the greenhouse temperature from rising much higher
than the outside temperature. Greenhouses collect solar radiation therefore it is normal for the inner
temperature to be higher than the outer. The ventilation system must move the air inside of the
greenhouse in order to keep the temperature from building up around the plants. In order for this
purpose to be achieved a combination of mechanical and natural circulation systems is needed.

Although ventilation in the winter is hardly used to keep the ideal temperature inside of the
greenhouse, the ventilation system is still as essential as the heating system, even when the heating is
working at its maximum in the coldest days, ventilation is required in the greenhouse to keep a uniform
air circulation. Fresh air must get in the greenhouse to prevent moisture. If the hot air is not removed,
high humidity and condensation will occur.

equipment. Not

ideal for

Concrete walls,

below-grade

stone walls,

unvented ceiling

and deck cavities,

since moisture

significantly cuts

the insulating

properties of

cellulose

properly fit; R-

value is greatly

reduced if not

installed properly;

can cause severe

itching and skin

rashes during

installation;

installers should

wear protective

gear and clothing.

Not ideal

for Unvented attic

and deck cavities

contractor; foams

are made of

petroleum

products. Not

ideal for Installing

near a furnace,

water tank or

fireplace, since

spray foam is

flammable; don’t

install open-

cell foam in leak-

prone spaces,

such as attics

major renovation,

such as replacing

siding or the roof,

or digging out

around the

foundation. Not

ideal for Attics,

walls, ceilings