Analysis of greenhouse located in Kashmir and proposing solution to meet its energy demands by solar energy sources.

Abstract

Plants need air, and sunlight in adequate quantity for proper growth. In northern Himalayan Regions, during the winter months temperature goes down to below 0 ⁰C and maintaining the right temper-Ture for the growth of plants becomes a challenge for farmers. Greenhouse provides a solution to this problem by artificially creating a controlled climatic condition for the growth of plants. The first objective of the research is to conduct an onsite study of a greenhouse located in Kashmir and identify the parameters that are controlled for the proper growth of the plants. Secondly, estimate the electric and thermal load of the greenhouse and propose a solution to meet it using solar energy sources. An onsite study was carried out on a greenhouse located in Kashmir where different types of plants like tomatoes, capsicum, and cabbage are grown. Inside the greenhouse, various climatic parameters are monitored and noted such as temperature, relative humidity and dew point. The study was carried out for the month of February and March. The maximum temperature recorded inside the greenhouse during February was 15.5 ⁰C while the maximum outside temperature was 6 ⁰C. For the month of March, the maximum temperature recorded inside the greenhouse is 25.6 ⁰C and the maximum temperature recorded outside is 15 ⁰C. A reduction in relative humidity was also observed with heating of the greenhouse with external devices that run on electricity generated from Solar PV. The electrical and thermal demand of the greenhouse is 94,800kWhr per day which is currently being met by electricity from the grid.

Full text

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Virtual mode conference, 22nd – 23rd, December 2021
Venue: Maejo University, Chiang Mai, Thailand
The 3rd International Conference on Renewable Energy,
Sustainable Environmental & Agri-Technological and Innovation
Analysis of greenhouse located in Kashmir and proposing solution
to meet its energy demands by solar energy sources
Obaid Ahmad Bhat, Subhra Das*
Department of Solar and Alternate Energy, Faculty of Science
Engineering and Technology, Amity University Gurugram, Haryana, India.
*Corresponding author, E-mail: sdas@ggn.amity.edu
Abstract. Plants need air, and sunlight in adequate quantity for proper growth. In northern Himalayan
Regions, during the winter months temperature goes down to below 0 ⁰C and maintaining the right temper-
Ture for the growth of plants becomes a challenge for farmers. Greenhouse provides a solution to this
problem by artificially creating a controlled climatic condition for the growth of plants. The first objective
of the research is to conduct an onsite study of a greenhouse located in Kashmir and identify the parameters
that are controlled for the proper growth of the plants. Secondly, estimate the electric and thermal load of
the greenhouse and propose a solution to meet it using solar energy sources. An onsite study was carried
out on a greenhouse located in Kashmir where different types of plants like tomatoes, capsicum, and
cabbage are grown. Inside the greenhouse, various climatic parameters are monitored and noted such as
temperature, relative humidity and dew point. The study was carried out for the month of February and
March. The maximum temperature recorded inside the greenhouse during February was 15.5 ⁰C while the
maximum outside temperature was 6 ⁰C. For the month of March, the maximum temperature recorded
inside the greenhouse is 25.6 ⁰C and the maximum temperature recorded outside is 15 ⁰C. A reduction in
relative humidity was also observed with heating of the greenhouse with external devices that run on
electricity generated from Solar PV. The electrical and thermal demand of the greenhouse is 94,800kWhr
per day which is currently being met by electricity from the grid.
Keywords: Greenhouse, Solar photovoltaic, Dew point, Moisture content
1. Introduction
Global energy consumption is increasing (Homdoung et al. 2020; Souvannasoukb et al. 2021). At
the same time, many countries' ever-increasing energy needs are being met with a combination of nuclear
power, renewable energy sources and fossil fuels (Mejica et al. 2021). The burning of fossil fuels causes
the emission of dangerous gases, which can lead to climate change, global warming and the degradation of
the environment (Ramaraj et al. 2016a; Mejica et al. 2022). The shortage of fossil fuels will cause a rise in
prices and a decrease in availability over the following decades. Many countries currently place their
primary focus on the extraction and conservation of natural energy resources that are environmentally
friendly (Ramaraj et al. 2016b; Whangchai et al. 2021). Promoting renewable and clean energy is one option
to meet the energy needs of both today and tomorrow. Many government organizations promote renewable
energy technology to reduce carbon dioxide emissions (Sophanodorn et al. 2022). It is difficult to decide
how to reach these goals while considering the cost and availability of resources and international
collaboration. While energy utilization has increased over the past decade, an energy generation system has
not yet been built to meet the energy demand (Chuanchai & Ramaraj, 2018; Tongmee et al. 2021).
Due to the high price of electricity, subsidies and circular debt are increasing. Studies have shown
that fossil fuels are causing global warming and environmental pollution. These shortages can be filled by
renewable energy sources like solar and wind, which do not emit greenhouse gases or poison the
environment. Many studies focus on individual energy sources such as solar, wind and biomass (Nong et
al., 2022). There are also suggestions for maximizing the potential of multiple renewable energy sources,
including solar, wind, micro-hydel and solar. The number of studies have been carried and put forward by
researchers to study the effects of solar radiation from the sun on the growth environment inside the

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greenhouse and various heat transfer mechanisms taking place inside the greenhouse and its effect on the
growth of plants. The production of crops has seen a decline in the production of the quantity of crops in
cold regions. The climatic condition is unfair the plant growth. Therefore, the improvement of climate
inside the greenhouse becomes very important for crop production to meet the food needs of the world. To
control the greenhouse microclimate, the system of heating and cooling are implemented within the
greenhouse. These changes within the greenhouse will have a better effect on the agriculture yield,
cultivation time, and quality of production (Sethi et al., 2008).
Particularly, the solar system based on thermal energy storage have been effectively applied to
the greenhouse (Lazaar et al., 2004) studied two types of heat transfer of solar heating passive and active.
The passive system works without any energy while the active system works on the exterior devices to
improve heat transfer. Sethi et al. (2008) have examined and discussed numerous studies of passive systems
based on workable and latent solar storage to rise the temperature inside the greenhouse. Barral et al. (2009)
reported that the passive system constituted of transparent and light synthetic thermal blanket improved the
winter horticulture production inside the greenhouse. Boudila et al. (2014) studied a new solar heating
system to study its impact on relative humidity and inside air temperature of the greenhouse. In one of the
research projects done for the month of January and February, the maximum global solar radiation falling
on the greenhouse varied between 750 and 850 W/m2, 700-830W/m2 and 600- 1000W/m2 in January,
February and March, respectively. The daily maximum and minimum temperatures were 28 and 2 ⁰C, 22-
3 ⁰C, and 25-10 ⁰C for measured periods in January, February and March respectively.
In one of the investigations done in China, a design was planned to use the strategy of a latent
heat storage system using phase change material for plastic greenhouse during winters, in hot summer and
cold winter climates. The outcome of this research were very encouraging, it showed that by using a
combination of insulation for plastic enveloped and phase change material and design made for phase
change material placement was able to maintain a good air temperature inside the greenhouse on sunny
winter days, without the use of phase change material, the air temperature inside the greenhouse was as low
as 3.7 ⁰C due to low ambient air temperature during cold winter nights (Shuqin Chen et al., 2020). Tomato
is a warm-season crop that grows during summer months in India, best temperature for its growth and proper
development is 20-30 ⁰C with moderate humidity and plenty of sunlight. Temperature during month of
March is best for seed sowing and transplanting is done once the temperature elevates. It is in the month of
April that crops can be cultivated in a greenhouse. Soil for cherry tomato must be high in organic content,
and sandy loam and the approximate pH should be between 0.5 to 7.5. The minimum water requirement
for outdoor growth of tomatoes is 4000-6000 m3/ha. In the greenhouse, it varies between 10,000m3/ha. This
study aimed to analyze the greenhouse located in Kashmir and propose soproposelution to meet its energy
demands with solar energy sources.
2. Materials and Methods
2.1 Greenhouse and its design
The work presented herein is largely based on the operational characteristics of greenhouses in
Kashmir Srinagar; a region having number of greenhouses in India. A greenhouse is a bounded structure
that creates a favorable micro-climate for crop production. They can produce much better crop yield with
more consistent crop quality than field crop. An arch-type greenhouse having a plan area of 2000m, gutter
height of 3.5 meters (m), with the length of 4 meters and width of 2 meters located in Srinagar area of
Kashmir having the Longitude: 74.8762972 and Latitude of: 34.1515846 Elevation: 1569m / 526 feet and
used for the cultivation of tomato plant. The structure is created with polycarbonate plastic. The frame of
greenhouse is made up of aluminum that provides strength to the structure. For natural ventilation movable
curtains are available on the sides of the structure to adjust the temperature inside the greenhouse.

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2.2 Electrical Demands of Greenhouse
To meet the electrical demands of the greenhouse Solar PV system has been installed on the
greenhouse. The power generated by the solar panels can be stored in the battery and can be utilized at the
time of need.
2.3 Calculation of load capacity of greenhouse
Table 1 Various electrical appliances used and their energy consumption.
Sr
Name of appliance
Watts
No
Total Watt
No of hours
Energy
1
Led Lamp
18
4
72
5
360
2
Exhaust Fan
70
4
280
10
2800
Total Watts = 252
Total Energy Consumed = Total Watts × Total Time = 3160.
For the period of 30 days = 3160 × 30 = 94800 kWhr.
Battery used = 150Ah. Nominal Voltage – 12V.
2.4 Solar thermal requirements of the greenhouse.
A greenhouse requires a lot of energy to produce an optimum crop during winter in its growth period.
For analysis purposes the heating system consists in this greenhouse is a passive heating type. In which water
is placed inside the greenhouse near the walls inside the black colored containers which are round in shape,
water inside these containers is the primary heat source. During the day time when the temperature inside
the greenhouse is high, the liquid absorbs the surrounding temperature and increases its own temperature,
and during the night when the temperature starts to fall below the ambient temperature of the plant, heat
from the water is released into the surrounding and help in maintaining the required temperature. A
greenhouse is a heat-storing system that converts incident radiation into heat gain. This physical process is
based on conduction, heat storage and convection.
Figure 1 Various heat exchanges taking place inside a greenhouse

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The greenhouse under investigation is based on four layers that include thermodynamic exchange, the
cover, internal air, the plant and the soil. The importance of each layer is given below:
• The main purpose of the cover is heat maintenance; usually, the cover is
made of polyethylene film or glass;
• The air inside represents an internal climate that is mainly administered by
temperature and humidity;
• The plant plays a very crucial role in water and heat balance, thanks to the
evapotranspiration process;
• The soil impacts the absorbance and diffusivity of the thermal radiation.
3. Results and discussion
The below details show the ambient temperature, humidity, and dew point measurement inside the
greenhouse having tomato plantation situated in Srinagar for the period of two months February and March.
The measurement period was characterized with snowy cold days of February and cloudy and rainy March
(Mohapatra et al., 2021). Maximum global solar radiation falling on greenhouse varies from
2.58kWh/m2/day to 2.70kWh/m2/day for the month of February and the month of March it varies between
3.85kWh/m2/day to 3.97kWh/m2/day. The climate during the February is colder compared to March. The
ambient temperature follows the same trend as solar radiation, and fluctuation also corresponds to the
fluctuation of solar irradiation received at the soil level (Newton et al., 1999). The maximum inside
temperature recorded in the greenhouse during the month of February is 15.5⁰C while the maximum outside
temperature recorded is 6⁰C. There is a clear 10 ⁰C temperature difference between inside and the outside
temperature for the month of February.
Figure 2 Temperature recorded inside greenhouse at various times during the day.
FEBEUARY VS
MARCH
0.00
5.00
0.00
5.00
0.00
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
29 30 31
DATE
MARCH
Temperature °C
FEBARUARY
Temperature°C

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Figure 3 Relative humidity recorded inside the greenhouse
Figure 4 Dew Point recorded inside the greenhouse.
At night the maximum temperature recorded outside is -2 ⁰C while the maximum night temperature
recorded inside the greenhouse is 6 ⁰C for the month of February. The temperature values can further be
improved by combining passive and active solar heating system inside the greenhouse. For the month of

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March, the measurements where repeated for measurement of temperature, relative humidity and dew point.
As the temperature in Kashmir starts to improve from the month of March it is visible in the measurements.
The maximum temperature measured inside the greenhouse is 25.6 ⁰C while the maximum outside measured
temperature is 15 ⁰C in the last week of March and the lowest measured temperature inside the greenhouse
is 8.8⁰C and the minimum outside temperature measured is 2 ⁰C. This significant improvement of inside
temperature of greenhouse leads to the conclusion that tomato plants can grow better inside the maintained
microclimate of a greenhouse (Jolliet et al., 1991). The relative humidity recorded during the two months
also shows good results, that are encouraging for the tomato plant during growth period. The maximum
relative humidity recorded is 92% and the lowest recorded value is 51.46%. From the recorded relative
humidity for the month of March the average value of relative humidity for the month of March is 67.5%
that is really good for the tomato plant.
Table 2 various climatic parameters recorded inside the greenhouse.
Particulars
February
March
Maximum Temperature Recorded
15.52 ⁰C
25.66 ⁰C
Minimum Temperature Recorded
1.52 ⁰C
8.81 ⁰C
Maximum Relative Humidity Recorded
97.58%
92.00%
Minimum Relative Humidity Recorded
74.54%
51.46%
Maximum Dew Point Recorded
10.93⁰C
13.4 3⁰C
Minimum Dew Point Recorded
1.55 ⁰C
5.01 ⁰C
Energy costs are a major economic factor in greenhouse operations. Heating system typically
represent the highest consumption of energy in greenhouse and can account for up to 90% of the total
demand. To make a greenhouse cost effective and self-sustainable in energy needs we can use a solar
photovoltaic system to meet the energy demand of the greenhouse (Sethi et al., 2008). The energy generated
from the solar cell can be stored in the batters and can be used whenever there is an energy demand. To
maintain the inside temperature of the greenhouse above the maintains level hot air blowers or heaters are
used, whenever inside micro temperature is low, to run these devices electricity generated from the solar
PV systems can be utilized whenever required. During summers months when temperature starts to increase,
exhaust fans can be used to regulate the inside temperature.
At night, when all the sides of greenhouse are closed. The inside air behaves like a closed
thermodynamic and exchanges energy with the external environment. The energy requirement (Qhr) of
greenhouse inside air, to have its nocturnal temperature equals to the optimum value of tomato growth (20
⁰C) is calculated by the following equation (1):
𝑇(Tin ⁡ ≥ Top )
Qh, r = ∑⁡ maca⁡(Top⁡(t) − Tin⁡(t)⁡⁡) (1)
𝑡 T in ≤ Top
where ma and ca are the air mass inside the greenhouse, 742.5kg, and specific heat of air at 25 ⁰C,
1005j/kg k. Top(t) and Tin(t) are optimum temperature for tomato plant and inside temperature respectively
(Ugar et al., 2015).

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The effect of combined heating system on the relative humidity in the experimental greenhouse shows
that the system is able to reduce the relative humidity value by 10 to 15% inside the greenhouse (Tiwari et
al., 2003). The optimal value of the relative humidity for tomato plant is 65% and beyond this value, plant
begins to stress, this combined active and passive heating system helps in restoring the humidity condition
favorable to the good growth of plant inside the greenhouse.
5. Conclusion
This research provides a detail overview of a greenhouse in cold climate of Kashmir. The following
Conclusions can be made from the results, optimal temperature for tomato plantation can be maintained
inside a greenhouse having polyester covering. During the research it was reported that tomato plant grows
better inside a greenhouse, a visible temperature difference of 4 to 6⁰C was recorded inside the
greenhouse a compared to outside temperature. Relative humidity can be maintained inside the
greenhouse by using appropriate methods that suite the plant growth. Solar PV (Photovoltaic
system) systems can be used both during winter and summer days to meet the heating and cooling
requirement of greenhouse. By including passive and active heating system techniques inside the
greenhouse, temperature of greenhouse can further be improved as per plant growth demand.
Passive and active heating system helps in maintaining appropriate relative humidity inside the
greenhouse.
Acknowledgements
ICAR – centre of temperature Horticulture. Ministry of New and Renewable Energy source (MNRE).
Sher-e-Kashmir university of agriculture sciences & technology Kashmir, Agri engineering division.
Meteorological department of Kashmir. http://www.metoffice.gov.
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