Designing an Aquaponic Greenhouse for an Urban Food

free material, not requiring paint, which could bring the price down in the long run. It also is easy to put
togeter or take apart to move it anywhere.

2.3.1.3 Greenhouse Coverings
Greenhouses are a way of protecting the crops from the outside environment, and as it is well known
the weather in New England is truly harsh. New England is well known for having all seasons well
defined, with a summer average of 85 degrees Fahrenheit and a winter average of 25 degrees
Fahrenheit. With that in mind, choosing the right structure and the right materials to protect the inside
is a top priority when designing a greenhouse.

When searching for materials to build the coverings of the greenhouse many aspects must be
considered. It needs to have light transparency for enough sun light to get in, but it also needs to be
strong and lasting to prevent damages. Adding to that, insulation is a major requirements for the New
England exceptional weather. Lastly, the cost, what is a major consideration that may dictate the
material used in the greenhouse design.

If a proper insulation gets overlooked, the cost of the greenhouse can become higher than it can be
afforded. Table 1 contains some information about some materials and their properties.

Light

transparency

Impact

resistance

Lasting

(years)

Insulation Heat loss Cost

Price/풇풕ퟐ

Solexx 70 - 75% yes 10 + 2.10-2.30 0.43-0.48 $1.50

Glass(single) 88% no Life long 1.5 1.5 $17.19

Multi-wall

polycarbonate

78% yes 10 + 1.6-2.5 0.5-0.7 $1.90

Single-wall

polycarbonate

80% no 10 + >1.6 >0.5 $1.83

Fiberglass 85 - 90% Yes 5 + 0.83 $2.26

Single-wall

film

85% no 3 - 5 0.87 >1.2 $0.15

Single-wall

acrylic

87% no 10 + >1.82 $3.61

(Greenhouses, n.d.); (Greenhouse Coverings, n.d.); (FarmTek, n.d.)

Table 1. Greenhouse Covering Materials and their properties

In the table above, lasting means that the material will not lose quality in the time line provided by the
table. For example, most plastics will start to become yellow losing transparency or light diffusion.

While conducting research on these materials, two of them stuck out as far as efficiency goes: Solexx
and traditional multi-wall polycarbonate. Both of them are multi-wall, with air in the middle acting as
insulation. Air entrapped in the small spaces in materials retards heat flow. This insulation
technique can reduce the heat loss and the energy costs with it. (John W. Bartok J. , 2007)

First, the Solexx, plastic panels made of high density polyethylene infused with UV inhibitors for a
warrantied life of at least 10 years without yellowing, the panels are 3.5mm to 5mm thick and said to be
impact resistant. Although Solexx is milky in color instead of transparent, it is said have a light diffusion
of 70 to 75%. (Megastore, n.d.)