Greenhouse Management Exam 1 Flashcards
What is a greenhouse range?
two or more greenhouses grouped together
What is a headhouse?
A service building containing restrooms, offices, storage, and a plant handling area (which typically takes up about 10% of the greenhouse space)
What is a hightunnel?
A structure covered with transparent material that admits sunlight, is tall enough to stand up in, has no permanent artificial heating, and has natural ventilation.
How should a greenhouse be oriented if it is located at a latitude 40 degrees above N?
East to West
How should a greenhouse be oriented if it is located at a latitude 40 degrees below N?
North to South
For gutter connected greenhouses how should the greenhouse be oriented in respect to direction?
North to South to prevent one greenhouse from overshadowing another
Quonset greenhouse
A freestanding greenhouse with bows but no side walls. One continuous curve
Gothic greenhouse
A greenhouse with some curve but has a point at the top.
Single span gable greenhouse
A greenhouse that has a slanted pointed roof
What is the difference between a strut and a chord?
Struts are under compression, chords are under tension.
Advantages of a detached greenhouse
lower initial cost, insects and diseases are more easily isolated and controlled, houses can be more easily located, environment can be controlled and changed.
Disadvantages of a detached greenhouse
higher heating and or ventilation costs, takes up more land area, more sophisticated in an environmental way opposed to economical
Advantages of a gutter connected greenhouse
more sophisticated environment control available, lower heating and ventilation costs, takes less land area, more economical
Disadvantages of a gutter connected greenhouse
higher initial cost, insects and or diseases not easily isolated or controlled, house cannot be relocated, different environments not possible.
Conduction
Heat conducted through a material
Convection
Heat exchange between a moving fluid (air) and a solid surface
Radiation
Heat transfer between two bodies without direct contact or transportation medium
Infiltration
Exchange of interior and exterior air through small holes in the building shell
What has higher heat loss?
Polyethylene film
What has higher light transmittance?
Glass panes
Infrared Radiation
Long wave radiation, radiant energy that’s invisible to the eyes, can only be felt in the form of heat.
Which covering prevents IR heat loss?
Glass
Which covering allows a lot of IR heat loss?
Polyethylene film
When does IR heat loss comprise the greatest % of heat loss from a greenhouse? Day or night?
Night
