Types of Green Houses

1. BIRSA AGRICULTURAL UNIVERSITY
Protected Cultivation and Secondary
Agriculture
LECTURE 5: Types of Green Houses
BY
DR. PRAMOD RAI
DEPARTMENT OF AGRICULTURAL ENGINEERIN

2. Types of GH
Classification of GH systems
Classification based on GH working
principles
GH type based on cost of construction or
technology
GH Type Based on Construction
GH Type Based on Covering Material
GH Type Based on Shape

3. Classification of GH systems
Free standing GH: Separate from other
buildings consisting of sidewalls, end walls, and
a roof
Solarium or attached GH: Attached to a
house

4. Greenhouse GH systems
Solarium
Crop drying
Crop production
Heating
of GH
Cooling
of GH
Heating Ventilated GH
Space heating Solar energy
collector
Active
Solar GH
drier
Natural Forced
Ventilation Evaporative
cooling
Buried pipe Movable insulation
North wall Ground air
collector
Natural Forced Natural Forced
Water tank
Heating
and
cooling
of GH
Free Standing

5. Classification of GH based on working principles
Passive GH
Do not require mechanical energy for moving fluids for their
operation. Fluids & energy move by virtue of temperature
gradients established by the absorption of radiation.
The GH act a collector, as the glazed area, walls and roofs are
used for collecting, storing and distribution of solar energy in the
GH by the natural processes of conduction, convection &
radiation.
It depend on architectural design to maximize solar gain in
winter to reduce heating and minimize them in summer to reduce
cooling.
Active GH
There is an external thermal energy available either from
conventional fuel or solar energy through a collector panel is fed
inside the GH.
These GHs use fan & pumps with the help of mechanical energy
to move the working fluid in the system.

6. Greenhouse
Passive
Greenhouse
Active
Greenhouse
Heating Cooling Heating Cooling
Water
Storage
Rock-bed
Storage
North Wall
Munching
Phase
Changing
Material
Movable
Insulation
Natural
Ventilation
Shading
Warm
Water
Soil Storage
Buried Pipes
Rock Piles
Forced
Ventilation
Evaporative
Earth Air
Tunnel
Misting

7. GH type based on cost of construction or
technology
Low cost or low tech GH
Medium cost or medium tech GH
High cost or hi-tech GH

8. Structu
re &
Glazing
Environment Culture
method
Expected
yield of
tomato
(kg/m2/yr)
Investme
nt cost
(Rs./m2)
Canopy Root
Bambo
o or
Wood
Single
layer
Passive
cooling
(roof and
side wall
vents)
No
heating
Soil
Drip
irrigation
with
manual
control
Med-
high
wire
10 – 20 300-500
Low cost or low tech GH

9. Structure
&
Glazing
Environment Culture
method
Expected
yield of
tomato
(kg/m2/yr)
Investmen
t cost
(Rs./m2)
Canopy Root
Steel
frame
Double
PE film or
rigid
plastic
Passive/A
ctive
cooling
(vents+pa
d/fan)
With or
without
air heating
Basic
level of
computer
Soil or
soiless
substrate
Drip
irrigation
Some
control
High
wire
culture
Longer
season
Usually
computer
ized
fertigatio
n
25 – 50 500 –1500
Medium cost or medium tech GH

10. Structure
&
Glazing
Environment Culture
method
Expected
yield of
tomato
(kg/m2/yr)
Investment
cost
(Rs./m2)
Canopy Root
Steel or
Aluminu
m frame
Glass,
polyethyle
ne or
Polycarbo
nate
Forced
ventilation
+
evaporativ
e cooling +
hot water
pipe
heating +
CO2
enrichment
+ shading
(light) +
energy
Soilless
substrate
Drip
irrigation
with full
automated
control
(EC
control
according
to light
intensity)
High wire
culture
Fully
computeri
zed
fertigation
Recirculat
ion
Hydroponi
cs
50 – 75
More than
1500
High cost or high tech GH

11. GH Type Based on Construction
Wooden framed structure
Pipe framed structure
Truss framed structure

12. Wooden framed structure
Being hygroscopic, it is generally treated for protection from
high moisture, termites & painted for better light condition
inside the GH.
Cromated copper arsenate (CCA) and ammoniacal copper
arsenate (ACA) is used for protection from moisture &
termites.
Bamboo/Timber available locally with good strength,
durability and machinability also can be used.
The GH with span less than 6 m are used.

13. Pipe framed structure
Used when the clear span is around 12 m.
The side posts, columns, cross ties and
purlins are constructed using pipes.
The trusses are not used.

14. Truss framed structure
The GH span is greater than or equal to 15m.
Flat steel, tubular steel or angular iron is used to form a
truss.
Most glass houses use truss frames.
Struts support members under compression and chords
support members under tension.
Angle iron purlins running throughout the length of GH
are bolted to each truss.
(Source: www.angrau.ac.in, www.gothicarchgreenhouses.com , www.redpath.co.nz )

15. GH Type Based on Covering Material
Glass GH
Plastic film GH
Rigid Panel GH
It has direct influence on the GH effect
and inside environment.
The types of frames & method of fixing
also varies with the covering material.

16. Glass GH
The maintenance of glass is high, though it provide good
transmission over time.
Transmit 84-87% of visible light, but it reduced to 70-75%
due to supporting structure provided to support it.
Available in different grades, weights, and sized.
Require more structural support than others.
Higher air infiltration rate, leads to lower interior humidity
and better disease prevention.
(source: www.gothicarchgreenhouses.com)

17. Plastic GH
It has as much as 90% transmittivity.
Its higher strength & low cost have made it most
popular replacement of glass.
Polyethylene, polyester and polyvinyl chloride
are used.
The cost of heating is less compared to glass GH.
Short life span & UV inhibitors increases life
span up to average of 3 years.
Available in various widths, lengths and
thickness.
Can produce condensation

18. Rigid Panel GH
Fibre glass-reinforced plastic (FRP)
Acrylic sheet
Polycarbonate sheet

19. Fibre glass-reinforced plastic (FRP)
These plastics consist of polyester resins, glass
fibers and can have minor amounts of other resins,
stabilizers etc.
It is available in flat and corrugated configurations.
Corrugated panels are commonly used for GH
roofs, as its shape lends strength and rigidity to the
panels.
Flat panels are usually used for sidewalls,
windows, and vents.
Susceptible to ultraviolet, dust & pollution
degradation, must use clear panels.
Highly flammable, therefore insurance rates maybe
higher than other coverings.

21. Acrylic sheet
Light weight in comparison to glass panel.
Flammable
It is available in thick or thin double wall
extruded sheets.
It is a less expensive alternative to
polycarbonate.
It is as transparent as the finest optical glass.
It has a high expansion and contraction
coefficient.
More resistant to breakage than glass, but less
than polycarbonate.
Attachment similar to polycarbonate.

23. Polycarbonate sheet
Most widely used.
Less heat is lost than glass panel.
UV protectant added to most products.
Available in corrugated, double wall, triple
wall.
Widely used to glaze end walls and gables
of Quonset houses.
Easily retrofitted to glass houses
High impact resistance
Not considered flammable

25. Characteristics of GH cladding material[a]
Type of Plastic Advantages Disadvantages Durability Light Transmission
Anti-drop UV-
stabilized
Wide and of variable
sizes, relatively
inexpensive, UV-
resistant
Expensive, requires
maintenance and can puncture
and tear easily
Fair, 2-3
years
Very good when kept
clean, 89% to 91%
UV-stabilized
Polyethylene Film
Wide and of variable
sizes, relatively
inexpensive, UV-
resistant
Requires maintenance and can
puncture and tear easily
Fair, 2-3
years
Very good when kept
clean, >90%
Polyethylene Film
Non-Stabilized
Inexpensive, wide and
of variable sizes
Requires maintenance and can
puncture and tear easily
Poor, 1 year Very good when kept
clean, >90%
Acrylic Weather-resistant and
break-resistant
Flammable, expensive, easily
scratched, not applicable to
tropical or warm climates
Very good,
>5 years
Very good, >90%
Polycarbonate Impact-resistant,
flexible, thin and
relatively inexpensive
Easily scratched, reduced light
transmission with ageing and
expands/contracts, not
applicable to tropical or warm
climates
Good, 5
years
Fair to good, 80% to
90%
Fiberglass Impact-resistant,
moderately prices and
easily cut
For smaller greenhouses,
expensive in larger scale,
reduced light transmission
with ageing, collects dust
easily
Very good,
>5 years
Fair, 80%
Polyvinyl Chloride
(PVC) and Ethylene-
vinyl acetate (EVA)
film
Allows UV through,
heat retention
properties
Not applicable to tropical or
warm climates, short lifespan
for rigid cladding
Fair, <5
years
Very good when kept
clean, 87% to 91%
[a] Adapted from Von Zabeltitz and Baudoin (2005), Von Zabeltitz (2011) and DeGannes et al. (2014).

26. GH Type Based on Shape
Solarium or attached GH: Connected to a house
Lean-to-GH, attached even-span GH, window-mounted
GH
Free standing GH: Separate from other buildings
consisting of sidewalls, end walls, and a roof
Quonset/hoop
Modified Quonset/arch
Gable even span GH
Gable uneven span GH
Connected GH: Several GH joined together
Saw tooth type
Ridge & furrow type or gutter connected
Venlo-Dutch Houses
Barrel vault

27. Solarium or attached GH
Placed against an existing wall
Common for institutional or hobby greenhouses
Typically facing south
(source: www.howtobuild-a-greenhouse.org, www.small-greenhouses.com,)

28. Quonset/hoop GH
Curve roofs without side walls.
The covering material used is polyethylene.
Less expensive than the gutter connected GH.
(source: www.gothicarchgreenhouses.com )

29. Modified Quonset/arch GH
A semi-circle design elevated by side walls.
Vining tomatoes, cucumbers, peppers, etc. can be
grown.

30. Gable even span GH
Two slopes of equal pitch and width
Most common configuration
Used for the GH of small size and is constructed
on level ground.

31. Gable uneven span GH
Constructed on hilly terrain
Roofs of unequal width and pitch
Good for high latitude sites

32. Saw tooth type
GH similar to ridge and furrow type GH except
that, there is provision for natural ventilation.
Upper portions of roof are vented to take
advantage of natural ventilation
(Source: www.netafim.com )

33. Ridge & furrow or gutter connected
Multiple A-frame spans connected along the eaves
The eave serves as furrow or gutter to carry rain
and melted snow away
Single large interior, consolidation of interior
space reduces labour, lowers the cost of
automation, improves personal management etc.
(Source: www.nafis.go.ke )

34. Greenhouse Structural Components
Basic structural components of a greenhouse: A) rafter, B)
end wall, C) side post, D) side wall, E) purlin.

41. If you have any question/suggestion
Mail me: pramod_kgp@yahoo.co.uk
Contact me on WhatsApp: 8986644713