Structural Details

The Top Sprouts greenhouse is a building integrated permanent structure, that provides an enclosed and controlled environment for year round food production while also greening the building.  Our sustainably designed greenhouse is built to recapture waste resources, such as building waste heat, rainwater, and solar and wind power to improve the energy efficiency of the greenhouse and the building.  To learn more about the various sustainable elements of the greenhouse, click here.

The basic greenhouse structure is pre-engineered and pre-fabricated galvanized steel or aluminum structure made of one-piece factory welded trusses supported by perimeter beams resting on columns.The structure is adaptable to a variety of covering styles, ventilation, heating and cooling systems to make the design most sustainable.The structure is connected to the underlying roof structure i.e. structural steel using post up steel tubing.  In rare cases, the greenhouse may be self supported by a gravity anchor which does not penetrate the roofing membrane.The covering of the greenhouse can be double layer polyethylene, multi-wall or corrugated polycarbonate, or glass – tempered, laminated, colored, insulated or Low-E.

Components

Cooling and Ventilation

As important as heating, a proper cooling and ventilation system is a necessary component. There are two options for cooling and ventilation: natural and mechanical. The appropriate combination of natural and mechanical cooling is determined during the design period.

Natural Cooling

The best form of cooling is natural ventilation. The greenhouse structure has atrium roof vents that act like chimneys allowing rising hot air to escape. The greenhouse is also equipped with side inlet vents – either guillotine or rack and pinion style. When operating in tandem, the side inlet and atrium vents allow for a natural upwards air flow, removing hot excess hot air through the atriums while pulling fresh air in through the side inlets.

Passive Mechanical Cooling

The standard option for mechanical cooling is the fan and pad evaporative cooling system.  Excess hot air is exhausted through side inlets via mechanical fans and fresh air is pulled in through water soaked evaporative cooling pads . There are several options within the system including pad materi al and fan style.

Heating

A proper heating system is an essential component of the greenhouse. There are two standard options for heating: forced air heating or hot water radiant heating. During the design period, the appropriate heating plan is determined based on greenhouse location, utility access, owner specifications and budget.

Forced Air Heating

In the forced air system, individual unit heaters blow hot air in

to the greenhouse; the heated air is then mixed via horizontal air flow fans. The individual heating units are mounted overhead to the trusses throughout the greenhouse and operate with hot water, natural gas, propane or oil. They are an efficient heat source given their low cost. The number of heaters required depends on the greenhouse size and desired greenhouse temperature.

Radiant Heating

There are two options for radiant heating: bare element fin tube radiation or floor embedded radiation. In the bare element fin tube system, copper piping runs above ground along the perimeter of the greenhouse structure; in the floor system, flexible tubing is embedded throughout the floor of the greenhouse. In both setups, hot water circulates throughout the piping system providing the heat. Radiant heating allows for more uniform heat distribution closer to the plants; the system also allows for multiple-zone heating.

Waste Heat Capture System

A waste heat capture system can be installed alongside the greenhouse. The system ties into the HVAC or venting system of the building and captures waste heat to be used to heat the greenhouse when additional heat is required during the night or in the winter. Costs for a waste heat capture system are estimated in phase one and the design established during the design period of phase two.

Growing Method

Water Culture

In the water culture method, plants grow in net pots with the their roots suspended in a nutrient solution. With the solution oxygenated by constant circulation, the roots remain submerged throughout the grow cycle. Though the water culture method is suitable for any plant, in the greenhouse it is best suited for leafy greens.

Nutrient Film

In the nutrient film method, plants grow in long, shallow channels that slope slightly downwards. A nutrient solution is pumped into the upper end of the channel and flows as a thin film downwards towards the other end. The root sit in this nutrient stream but are not submerged, having a constant re-circulating nutrient and oxygen supply. Like the ebb and flow method, the nutrient film technique is suitable for any plant but in the greenhouse used for larger vegetables such as tomatoes.