This document provides an overview of renewable energy technologies for greenhouse climate control presented by E. Venkatesh. It discusses different types of greenhouses based on shape, use, construction material, and covering material. Greenhouses can be classified as active heating or cooling depending on their intended use. The document also covers greenhouse climate factors like light, air temperature, soil temperature, and carbon dioxide concentration that influence plant growth. Maintaining optimal levels of these factors is important for maximum photosynthesis and crop productivity in greenhouses.

1. SEMINAR-I
ON
“APPLICATIONS OF RENEWABLE ENERGY
TECHNOLOGIES FOR CONTROLLED ATMOSPHERE OF
GREEN HOUSE”
PRESENT BY ,
E.VENKATESH
PG18AEG10105
UNIVERSITY OF AGRICULTURAL SCIENCES, RAICHUR
COLLEGE OFAGRICULTURAL ENGINEERING,RAICHUR
DEPT. OF FARM MACHINERY
AND
POWER ENGINEERING

2. INTRODUCTION
• “Greenhouse technology is the science of providing favourable
environmental conditions to the plants”.
• In some of the regions where the climatic conditions are extremely
adverse and no crops can be grown, man has developed technological
methods of growing some high value crops by providing protection
from cold, heat wind, cold, precipitation, excessive radiation,
extreme temperature, insects and diseases.
• An ideal micro climate can be created around the plants. This is
called “Greenhouse Technology”.
2
Source:ecoursesonline.iasri.res.in

3. • There are more than 55 countries
now in the world where cultivation of
crops is undertaken on a commercial
scale under cover and it is
continuously growing at a fast rate
internationally.
• Indian Agricultural productivity
should equal those countries, which
are currently rated as economic
power of the world.
• The greenhouse system may be one
key element to sustain food for
growing Indian population/economy.
3
SCOPE ON GREENHOUSES AROUND THE WORLD
Country Area (ha)
Netherland 89,600
China 51,000
Japan 40,000
Spain 28,000
South Korea 21, 000
Italy 19,500
Israel 18,000
USA 15,000
Turkey 12,000
India 5,730 (2012)
Source: www.small-greenhouses.com

4. CLASSIFICATION
Types of greenhouses based on shape, utility, material and construction,
Based On Shape
• Lean to type greenhouse
• Even span type greenhouse
• Uneven span type greenhouse
• Ridge and furrow type
• Saw tooth type
• Quonset greenhouse
• Interlocking ridges
4
Source:ecoursesonline.iasri.res.in

5. 5
Lean-to-type type greenhouses
(source: www.howtobuild-a-
greenhouse.org, www.small-greenhouses.com,)
Even Span Type Greenhouse
(source: www.arcadiaglasshouse.com,)

6. 6
Uneven Span Type Greenhouse
Ridge and furrow type greenhouses
(Source: www.nafis.go.ke )

7. 7
Saw tooth type greenhouses
(Source: www.netafim.com )
Quonset Type Greenhouse
(source: www.gothicarchgreenhouses.com )

8. Based on Utility
Classification can be made depending on the functions or utilities.
of the different utilities,
• Greenhouses for active heating.
• Greenhouses for active cooling.
Active Heating
• During the night time, air temperature inside greenhouse decreases.
To avoid the cold bite to plants due to freezing, some amount of heat
has to be supplied. The requirements for heating greenhouse depend
on the rate at which the heat is lost to the outside environment.
• Various methods are adopted to reduce the heat losses, viz., using
double layer polyethylene, thermo pane glasses or to use heating
systems, such as unit heaters, central heat, radiant heat and solar
heating
8Source:ecoursesonline.iasri.res.in

9. Active cooling
• During summer season, it is desirable to reduce the temperatures of
greenhouse than the ambient temperatures, for effective crop
growth.
• Suitable modifications are made in the green house so that large
volumes of cooled air is drawn into greenhouse, This type of
greenhouse either consists of evaporative cooling pad with fan or
fog cooling.
• This greenhouse is designed in such a way that it permits a roof
opening of 40% and in some cases nearly 100%.
Greenhouse Type Based on Construction
• The type of construction predominantly is influenced by structural
material, though the covering material also influences the type.
• Higher the span, stronger should be the material and more structural
members are used to make sturdy tissues. For smaller spans, simple
designs like hoops can be followed
9
Source:ecoursesonline.iasri.res.in

10. Based on Covering Material
Glass
Plastic flim
Rigid panel
10
Source:ecoursesonline.iasri.res.in

11. • The yield may be 10-12 times higher than that of outdoor cultivation
depending upon the type of greenhouse, type of crop, environmental
control facilities.
• Reliability of crop increases under greenhouse cultivation.
• Ideally suited for vegetables and flower crops.
• Year round production of floricultural crops.
• Off-season production of vegetable and fruit crops.
• Disease-free and genetically superior transplants can be produced
continuously.
• Efficient utilization of chemicals, pesticides to control pest and
diseases.
11
FUNCTIONS OF GREEN HOUSE
Source:ecoursesonline.iasri.res.in

12. • Water requirement of crops very limited and easy to control.
• Maintenance of stock plants, cultivating grafted plant-lets and micro
propagated plant-lets.
• Hardening of tissue cultured plants
• Production of quality produce free of blemishes.
• Most useful in monitoring and controlling the instability of various
ecological system.
• Modern techniques of Hydroponic (Soil less culture), Aeroponics and
Nutrient film techniques are possible only under greenhouse
cultivation.
12
CONTD..
Source:ecoursesonline.iasri.res.in

13. • The greenhouse climate factors required for the optimal plant
development involve photosynthesis and respiration.
• Photosynthesis, or the active process, is the formation of carbon
dioxide through solar radiation and can be expressed by the following
simplified balance equation:
6CO2 + 6H2O + 2,810 kJ = C6H12O6 + 6O2
On the contrary, respiration is expressed as:
C6H12O6 + 6O2 = 6CO2 + 6H2O +2 ,810kJ
• It is not possible to understand greenhouse energy demands in order
to calculate heat requirements, without the essential knowledge of the
"greenhouse climate.“
13
GREENHOUSE CLIMATE
Source:(Popovski, 1997).

14. 14
Physical phenomena responsible for differentiating greenhouse and
external climatic conditions:
1. Solar radiation, in particular the short waves, penetrates the glass or
plastic covering of the greenhouse practically without any loss. On
reaching the soil surface, plant canopy, heating installation, etc., the
radiation changes to long-wave, and can no longer pass through the
covering, or with difficulty. Most of the radiation is trapped within
the greenhouse space, raising the inside temperature;
2. The enclosed air within the greenhouse is stagnant: local air velocity
is much smaller than it is outside and the effects of temperature
transfer are entirely different;
3. The concentration of plant mass in the greenhouse space is much
higher than outside. Artificial control of humidity and condensation
clearly creates a different mass transfer from outside the greenhouse,
and
4. The presence of heating and other installations changes some of the
energy characteristics of greenhouse climate. Source:(Popovski, 1997).

15. • Light is the most significant parameter for the plant development and life.
All the active life process in it can be achieved only in the presence and
active influence of light.
• When speaking about natural light, meaning solar light, it is necessary to
distinguish:
Solar radiation with specific influence to the life processes of the
plants,
 Solar radiation with energy related influence to the plants, directly or
indirectly through the influence of the environment
• By the use of different scientific methodologies and investigations of
changes in photosynthetical, phototropical,photomorphogenical and other
plant activities, it is found that only the part of total solar spectrum
between 400 and 700 nm influences significantly plants life processes.
• That determines the quality of transparent materials for greenhouse
cover– it must be maximally transparent to this part of the solar spectrum.
15
LIGHT

16. 16
• The intensity of the energy related part of the total spectrum of solar
radiation offers the necessary energy to the plant . Depending on its
intensity, life processes are more or less active.
• Up to some characteristical levels life processes increase their
activities; but, after a point, they start to decrease. Below and above
these characteristical light intensities, there is no life activity in the
plant.
• Below, because active life processes need light to be activated.
Above,because the plant is over- heated and processes of "cooling“
are activated.
• To improve light conditions, artificial light is used when the natural
one is not available, or shaded when the light intensity is too high.
• Light intensity also affects the values of other parameters of
greenhouse climate.
Source:(Popovski, 1997).

17. 17
Average specter of absorption "in vitro" of chlorophyll
pigments (Popovski, 1997).

18. • Air temperature influences the energy balance of the plant canopy
through the convective heat transfer to the plant leaves and bodies.
• Depending on the character of the air movement in the greenhouse, it is
more or less near the temperature of the plant itself.
• The optimal level of the air temperature in the greenhouse depends on
the photosynthetical activity of the plant in question, under the
influence of the intensity of solar radiation on disposal.
• the changeable character of greenhouse climate, it is not possible to
provide the "optimal" air temperature for some plants due to
interdependencies of the light intensity and other parameters of
greenhouse climate.
18
AIR TEMPERATURE
Source:(Popovski, 1997).

19. 19
Photosynthesis activity vs. light and air
temperature conditions (tomato culture)
(Popovski, 1997).

20. • Soil, or plant base temperature influences the energy balance of the
plant canopy, too. The influence is by conduction heat transfer
directly between the soil structure and through convection between
the plant roots and water flow around them.
• Through a great number of experiments and investigations, it is
proven that:
• Optimal soil temperature depends on the stage of development of
the plant
• Optimal soil temperature depends on the light intensity available,
and
• Soil temperature influences the value of the optimal air
temperature.
20
SOIL OR PLANT BASE TEMPERATURE
Source:(Popovski, 1997).

21. • Normal CO2 concentration in the atmosphere is about 0.03%.
• In the case of a closed room under influence of high light intensity
and, high photosynthetical activity, it changes quickly.
• During a bright day, its concentration can decrease to 0.01% in only a
couple of hours for a good tight greenhouse.
• The CO2 is an active participant of the chlorophyll assimilation, it is
a greenhouse parameter of crucial importance.
• As Optimal concentration of CO2 in the greenhouse depends directly
on the light intensity on disposal.
21
CO2 CONCENTRATION
Source:(Popovski, 1997).

22. 22
Optimal concentration of CO2 in the cultivation
area of a greenhouse depending on the light intensity
(Popovski, 1997).

23. • The character and velocity of the air movement in the greenhouse
influence
The intensity of the heat transfer between the air and plant
canopy, and
The intensity of the water exchange between the air and plant
canopy.
• At the same time, both processes are directly connected to the energy
balance of the plant canopy and, in that way, the intensity of the life
processes in it.
23
AIR MOVEMENT
Source:(Popovski, 1997).

24. • Water transport between the plant canopy and the environment is one
of the most important parameters of the photosynthetical activity.
• Root characteristics of the plant in combination with the ability of the
cultivation base to offer the necessary water quantity, but also on the
air humidity of the plant environment.
• Air humidity directly influences transpiration of the plant leaves.
• Lower humidity means drying of the plant and reduced production.
• Higher humidity produces more leaves, lower quality of fruits and
sensitive to a number of plant diseases.
24
WATER TRANSPORT
Source:(Popovski, 1997).

25. GROUND SOURCE HEAT PUMP
• The basic principle on which the GSHP works is "refrigeration
cycle". The refrigerant carries the heat from one "space" to another.
The heat pump's process can be reversed. The earth is the main
source and sink of heat. In winters, it provides heat and summers it
takes the heat.
• Ground Source Heat Pumps (GSHP’s) use the earth's relatively
constant temperature between 16 - 24oC at a depth of 20 feet. GSHP
harvests heat absorbed at the Earth's surface from solar energy.
• Heating efficiencies 50 to 70% higher than other heating systems and
cooling efficiencies 40 to 50% higher than available air conditioners.
25
Source:http://www.nzeb.in/

26. 26
Source: Youtube

27. CASE STUDY:I
Title: Experimental evaluation of using various renewable energy
sources for heating a greenhouse
Authors: Mehmet Esen, Takhsin Yuksei
Journal: Energy and Buildings
Place: sultanusagi village, Turkey.
Period :10th of November 2009 to 31st of March 2010.
Objectives: To demonstrate that some renewable energy sources
such as biogas, ground and solar energy can be efficiently used to
heat a greenhouse during the typical winter conditions in eastern
Turkey.
27

28. 28
MATERIALS AND METHODOLOGY

29. 29
Fig.1 Schematic representation of the greenhouse heating system.

30. 30
Fig.2 The sketch of temperature measurement points of BSGSHPGHS, temperatures
(T1, T2, T3, T4, T5, T6: ground; T7: biogas water tank; T8: blowing up fan-coil;
T9:outdoor area; T10: inlet of ground heat exchanger; T11: outlet of ground heat
exchanger; T12: inlet of solar collectors; T13: outlet of solar collectors; T14: inlet of
compressor;T15: outlet of compressor; T16: condenser fan; T17: tank of ground heat
exchanger and solar system; T18: indoor greenhouse; T19: generator; T20 ground at 5
cm). (For interpretation of the references to color in text, the reader is referred to the
web version of this article.)

31. 31

32. Measurements
(a) Measurement of mass flow rates of biogas by a gasometer.
(b) Measurement of temperature of the biogas reactor, ground, the water-
antifreeze solution entering and leaving the slinky ground heat exchanger and flat
plate solar collectors by copper-constantan thermocouples mounted on the water-
antifreeze solution inlet and outlet lines.
(c) Measurement of mass flow rates of the brine (water-antifreeze solution) by a
rotameter.
(d) Measurement of mass flow rates of the refrigerant (R22) by a flowmeter.
(e) Measurement of compressor, condenser and evaporator pressures by
manometers.
(f) Measurement of ambient atmospheric pressure by a barometer.
(g) Measurement of outdoor and greenhouse air temperatures and humidities by
using multi-channel cable free thermos hygrometer.
(h) Measurement of electrical power input to the heater, mixer pump, fan-coil
unit, compressor and circulating pump by a wattmeter.
(i) Measurement of solar radiation by Kipp&Zonen pyranometer.
32

33. Result and discussion
33

34. 34

35. 35

36. 36

37. 37

38. 38

39. 39

40. 40

41. Key findings
• As temperature changes are adverse influence on the formation of
methane in reactor, it was achieved success to maintain a constant
temperature of 27 ◦C within reactor. By the biogas system, the
greenhouse temperature was able to keep at about 23 ◦C.
• It was seen that the slinky-type heat exchanger occupying less space in
ground can be successfully used for greenhouse heating.
• Solar energy system as a standalone solution can be feasible with high
storage temperatures.
• As biogas plants used to generate electricity and heat as well as a fuel,
the greenhouse costs may be more attractive in region
• Solar energy can be stored under ground and then used to raise soil
temperature and to heat biogas reactor.
41

42. CASE STUDY:II
Title: Prototype semi-transparent photovoltaic modules
for greenhouse roof applications
Authors : Akira Yano, Mahiro Onoe , Josuke Nakata
Journal: Biosystems engineering.
Place : shimane, Japan.
Period : 2014
Objectives: Improved energy efficiency and the increased use
of renewable energy are important for sustainable greenhouse
crop production.
42

43. MATERIALS AND METHODOLOGY
43
Cross-sectional structure of the spherical solar microcell (Sphelar,
a) and the proto type PV modules (b) with 15.4 cells cmL2 (PV1,
c) or 5.1 cells cmL2 (PV2, (d) cell density.

44. 44
Configuration of sunlight, shading, and PV module output measurements. PV1 and
PV2 modules and pyranometersP1, P2, and P3 (a) were mounted 2m above the wild-
plant covered ground (b), on which two horizontal white plates had been positioned
for tracking the PV cell shadows. P5 and P6 respectively measured IHS1 and IHS2. P4 was
positioned at the margin of the PV1 cell shadow. All pyranometer and PV module
output data were stored synchronously in the PC through the GPIB interface (c).

45. 45
Nomenclature
d distance between the PV module and an observation point in the PV cell
shadow,
e1 solar eclipsing percentage by PV1 cells, %
E2 solar eclipsing percentage by PV2 cells, %
IHT global irradiance on a horizontal plane, W m2
IHS1 horizontal global irradiance in the PV1 cell shadow, W m2
IHS2 horizontal global irradiance in the PV2 cell shadow, W m2
IT global irradiance on the inclined PV top surface,Wm2
ITr ground-reflected irradiance on the inclined PV bottom surface, W m2
p atmospheric transmissivity, %
Pmax peak power value of a Ppv-V characteristic curve of the PV modules, W
Ppv power output of the PV modules, W
So shading percentage of the PV-module’s transparent cover materials, %
Β tilt angle of the PV modules,
γ angle between direct sunlight incidence and the sky-directing PV-module’s
normal,
η module efficiency, %
ψp azimuth of the PV module’s normal from the south,

46. 46
Results and discussion
Measured (solid lines) and calculated (dotted lines) global irradiance on
the horizontal plane IHT on (a)5 May, (b) 22 April. Atmospheric
transmissivity ρ-0.65

47. 47
Measured (solid lines) and calculated (dotted lines) global irradiance on
the horizontal plane IHT on (c) 13 May, (d) 17may. Atmospheric
transmissivity ρ-0.65

48. 48
(a) 5 May, (b) 22 April

49. 49
(c)13 May, (d)17 May, (e) 21 May, (f) 22 May

50. 50
I-V (a, b, c, g, h, and i) and PPV-V (d, e, f, j, k, and l) characteristics of the PV1(a-f) and
PV2 (g-l) modules. The PV modules’ top surfaces were directed southward to the sky
(a, d, g, and j), to the north sky (b, e, h, and k), or to the east sky (c,f, i, and l).

51. 51
I-V (a, b, c, g, h, and i) and PPV-V (d, e, f, j, k, and l) characteristics of the PV1(a-f) and
PV2 (g-l) modules. The PV modules’ top surfaces were directed southward to the sky
(a, d, g, and j), to the north sky (b, e, h, and k), or to the east sky (c,f, i, and l).

52. 52
Relation between peak PV power output Pmax and IT D ITr (a) of the south-
sky facing PV1 (open red diamonds) and PV2 (open red squares), the north-
sky facing PV1 (open grey circles) and PV2 (open black triangles), and the
east-sky facing PV1 (black dots) and PV2 (grey dots), and the relation
between module efficiency η and IT D ITr (b).

53. 53
Calculated angle γ of the south-sky facing PV1 (red long-dashed line)
and PV2 (red dotted-dashed line), the north-sky facing PV1 (grey dashed
line) and PV2 (grey double-dotted dashed line), and the east-sky facing
PV1 (black dotted line) and PV2 (black solid line) modules;

54. 54
(b)relation between η and γ

55. 55
The relation between Pmax and γ

56. 56
Measured shading percentages of global irradiation on the horizontal
plane by the PV1 cells (open triangles), PV2 cells (open squares), and the
transparent module materials (open circles).

57. 57
Greenhouse
orientation
PV
modules
PV roof coverage Annual electrical energy
production per unit
greenhouse area
(kWhm-2yr-1)
East-West PV1 South roof only 64
North roof only 39
South and north roofs 102
PV2 South roof only 23
North roof only 14
South and north roofs 36
North-South PV1 East or West roof only 55
East and west roofs 110
PV2 East or West roof only 20
East and west roofs 39

58. 58
Location Electrical load Annual electrical
energy consumption
per unit greenhouse
area (kWhrm-2yr-1)
Reference
Mediterranean Heating, cooling,
ventilation
2-9 Campiotti et
al.(2008)
Spain Windowing operation,
pumps,
3 Urena-Sanchez et
al.(2012)
Spain Fans, irrigation and
fertilization equipment,
fuel burner, window
opening, screen motors,
automatism for climate
control, compressor,
electric resistance of the
fuel reservoir
7 Rocamora and
Tripanahnostopoulose
t al.(2006)
Greece Ventilation, cooling,
lighting
20 Souliotis et al.(2006)
Saudi Arabia Fan, cooling pump, PC 56 Al-Ibrahim et
al.(2006)
Sweden Ventilation, pumps,
lighting and other devices
140 Vadiee and Martin et
al.(2013)

59. • Key findings
• The maximum power output of the single cell is 0.48 mW. The
optimum operating voltage is 0.48 V. The optimum operating current is
1.01 mA. The light-electricity conversion efficiency is 18.9% for
standard evaluation conditions.
• For the best accuracy, η= 4.5% at γ=7.4º, which was the minimum
incident angle of direct solar irradiance, was determined as the
efficiency of the PV1 module. Similarly, η =1.6% at γ =3.1º was
determined as the efficiency of the PV2 module.
• The mean shading percentages of the PV1 and PV2 cell area were,
respectively, 43% and 23%. The shading percentage remained a
constant value in γ < 20º.
59

60. Conclusion
• For any renewable energy technology need certain basic
required environment condition
• Combination of renewable energy technologies to get
required output form of energy
• Initial investment of this form technology is high
• Except sun all the form of energy require investment for
conversion, storage, utilization
60

61. Reference
• Esen, M. and Yuksel, T., 2013, Experimental evaluation of using various renewable
energy sources for heating a greenhouse. Energy and buildings, 65: 340-351.
• Yano, A., Onoe, M. and Nakata, J.,2014, Prototype semi-transparent photovoltaic
modules for greenhouse roof applications. Biosystems Engineering,122: 62-73.
• Ozgener, O. and Hepbasli, A., 2006, An economical analysis on a solar greenhouse
• integrated solar assisted geothermal heat pump system, Journal of Energy
• Resources Technology, 128 (1):28–34.
• Popovski, K., 1997, GREENHOUSE CLIMATE FACTORS. GHC BULLETIN, 1: 14-20.
• Sethi, V. P. and Sharma, S. K., 2008, Survey and evaluation of heating technologies for
• world wide agricultural greenhouse applications. Solar energy, 82(9): 832-859.
• Sethi, V. P. and Sharma, S. K., 2007, Survey of cooling technologies for world wide
agricultural greenhouse applications. Solar energy, 81(12): 1447-1459.
• www:ecoursesonline.iasri.res.in
• www.arcadiaglasshouse.com
• www.howtobuild-a-greenhouse.org
• www.small-greenhouses.com
61

62. 62
Thank You!