3.3.2 Interior Layout...................................................................................................................
The internal layout is an important key to having a successful growing operation. In an effort to
maximize the productivity of the greenhouse we engaged in discussion with the sponsor about the
criteria and constraints for the design. An internal design designating the position of the tanks and beds
relative to each other was then synthesized to reflect the ideas of the sponsors. These ideas included
enough space for moving around and demonstrations and efficiently organized tanks and beds for
maximum productivity. These designs were created using the program Solid Works and their feasibilities
compared.
The constraints for the internal layout that were to be researched and compared were the tanks, the
growing beds, the walkways, and the width of the doorways. Growing beds were designed using the
Solid Works program and the design for the tanks were researched to see what shapes would
accommodate the best circulation of water. The length of the walkways and the width of the door were
cross referenced with building codes and other designs to see that they had both functionality and
comfort for the users of the greenhouse.
3.3.3 Interior Heating
The interior design with the ecosystem cannot function without adequate heating when we consider the
climatic zone in which this greenhouse will be constructed. The most important factors to take into
consideration are the temperature and the sunny days. Data on the average daily temperatures, and the
amount of sunny days during the winter months were retrieved from National Oceanic and Atmospheric
Administration (NOAA) for the city of Worcester in last 50 years. These data sets were used to calculate
how much it would cost to heat the greenhouse to a temperature suitable for plant and fish growth.
Insulation is another factor that will affect the heating of the greenhouse. The heat loss of the material
used to cover the greenhouse is an important consideration. The average monthly heat loss was
calculated using the worst commercially available insulator, for the calculations we also assumed that
the exterior temperature would be equivalent to the average low of previous years, the temperature
needed for germination of plants was 65F and water temperature needed to support fish life was 75F.
The heat loss was then used to determine how much heat needed to be supplied to the system to
maintain these specific temperatures. Other factors that affected the heating process such as the
circulation of water were also included in the calculations then the energy value was then translated
into monetary units to predict the monthly cost to sustain the system.
3.4 Designing Growing System
3.4.1 Plant and Fish
The next step in the project was to determine the maximum size of the ecosystem that the best interior
layout could support. Preliminary research into the amount of nutrients needed for plant growth and
the amount of dissolved oxygen and microbes that were necessary for fish growth were conducted.
These values were then tabulated to determine specific ratios necessary for the operation of the
aquaponic system. The preliminary calculations were then used in parallel with other findings in the
literature and information from members in the aquaponic community to determine these specific
ratios. The ratios include the amount of water needed per pound of fish, and the amount of fish needed
to sustain one square foot of growing bed.