The Canadian Integrated Northern Greenhouse: A Hybrid Solution for Food Security

*David Leroux and Mark Lefsrud*

## **Abstract**

Food security has become a prominent issue in northern Canada. Many constraints, including environmental, cultural and economic barriers to cause food insecurity in northern Canada where local food production is one proposed solution to the northern food crisis. Initiated at McGill University by the Biomass Production Laboratory, the Canadian Integrative Northern Greenhouse (CING) unit provides a completely integrative design solution that could allow northern Canadian communities to grow their own fresh and nutritious food year-round. The CING unit is a hybrid between a northern greenhouse and a growth chamber housed in a shipping container, designed to be adaptive by functioning as a typical solar greenhouse when solar light provides considerable heat and light, and as a closed growth chamber during the night and when colder, darker winter conditions prevail. The CING was designed and prototyped by McGill students since 2013. Lettuce was grown during the four-season test of the CING, the greatest yield obtained was in March 2019, where the plants grown achieved 72% of the dry mass of the plants grown in the research greenhouse. The CING relied on supplemental heating to successfully grow plants but demonstrated the potential for northern and remote applications.

**Keywords:** shipping container farming, controlled environment agriculture, northern agriculture, northern greenhouse, organic fertilizer

## **1. Introduction**

The CING is designed as a hybrid between a closed growth chamber and a greenhouse to optimize energy requirements related to the production of fresh produce throughout the year. The unit can open to allow sunlight to enter, utilizing the unit's greenhouse function, or be completely covered by an insulated thermal curtain, employing the unit's growth chamber function. Specific exterior and interior conditions dictate when the use of each mode is most efficient to promote the best interior conditions. To determine and predict these conditions, climatic and environmental data were recorded outside and inside the CING prototype situated at McGill University's Macdonald Campus in Sainte-Anne-de-Bellevue, QC, since summer 2015.

## **1.1 Container farming**

Container farming (CF) is an indoor agricultural practice falling under the Controlled Environment Agriculture (CEA) category [1]. Plants are grown hydroponically in a shipping container with electrical lighting and most of the environmental parameters are controlled by the grower. Converting a shipping container into an indoor farm has many advantages. First, a shipping container is an inexpensive infrastructure. Buying a refurbished shipping container and modifying its structure by cutting through the walls is still considered cheaper than buying a new building. Second, transportation, if the structural components of a shipping container are intact (i.e. the four corner beams), the CF has a strong foundation that can be moved as a typical shipping container. In this way, it acts as a mobile agricultural unit. Third, a converted shipping container's internal environment is independent of environmental parameters. In an insulated environment comprising electrical lighting, soil-less cultures, and heating ventilating and air conditioning (HVAC) technologies, it is possible to grow crops in any climate. Finally, a converted shipping container offers a high yield per square meter. Using vertical farming in which five levels of shallow water hydroponic cultures of lettuce are stacked, it is possible to grow 20 times more produce per square meter in a CF than field agriculture with corresponding yields of 1000 plants. m<sup>2</sup> [2].

CF is still a relatively new agricultural practice, and indoor farmers do not necessarily agree that this new agricultural practice is economically viable, still being considered an overhyped technology, with only 50% of container farms being profitable in the U.S. [3]. Yet CF has many different styles, with companies such as Freight Farms, Growtainers, and Cubic Farms offering similar options to grow crops in urban or remote areas [4] (**Figure 1**). According to case studies from companies like Bright Agrotech and independent reports from universities such as the University of Bonn in Germany and the Massachusetts Institute of Technology, vertical farming and CF can be economically profitable and viable depending on different economic parameters, such as market, labor and cheap energy availability [5].

From these energy values, except for growing tomatoes in a transparent wall shipping container in New York City where the well-insulated opaque wall helped reduce heat loss in a colder month, using transparent walls in a shipping container would reduce the energy needs to grow certain food crops in CF, even for Lettuce during cold months [6]. Following these findings, the CING was not modeled for its energy use, rather, design and experimental approach was chosen to test the use of

*A module for the Minimally Structured & Modular Vertical Farm, designed by Dr. Cuello from the University*

**Transparent wall**

*The Canadian Integrated Northern Greenhouse: A Hybrid Solution for Food Security*

Tomato 240.06 381.30 557.65 325.34 Lettuce 418.38 1950.99 773.84 1640.85

**Los Angeles New York City**

**Transparent wall**

**Opaque wall**

**Opaque wall**

The CING was first designed in 2013 by Bioresource engineering students at McGill University (**Figures 3** and **4**). A shipping container was purchased in 2015.

natural lighting in CF in a cold climate.

*Summary of annual energy consumption in kWh/m2 [6].*

*DOI: http://dx.doi.org/10.5772/intechopen.96214*

**2. Materials and methods**

**2.1 Design of the CING**

**Figure 2***.*

**Table 1.**

**Figure 3.**

**51**

*Original design of the CING.*

*of Arizona (Liu, 2014).*

**(kWh/m<sup>2</sup> )**

**Annual Energy Estimation**

The concept of a modified shipping container for controlled environment agriculture is not new (**Figure 2**). Strategies using modified shipping containers with natural lighting has been made for conditions comparable to those found in New York City and Los Angeles by the University of Arizona. From these simulations, it was determined that shipping containers with transparent walls have a much lower energy consumption than opaque and well-insulated walls (**Table 1**) [6].

**Figure 1***. Outside of the CING, December 2017.*

*The Canadian Integrated Northern Greenhouse: A Hybrid Solution for Food Security DOI: http://dx.doi.org/10.5772/intechopen.96214*

#### **Figure 2***.*

**1.1 Container farming**

*Next-Generation Greenhouses for Food Security*

Container farming (CF) is an indoor agricultural practice falling under the Controlled Environment Agriculture (CEA) category [1]. Plants are grown hydroponically in a shipping container with electrical lighting and most of the environmental parameters are controlled by the grower. Converting a shipping container into an indoor farm has many advantages. First, a shipping container is an inexpensive infrastructure. Buying a refurbished shipping container and modifying its structure by cutting through the walls is still considered cheaper than buying a new building. Second, transportation, if the structural components of a shipping container are intact (i.e. the four corner beams), the CF has a strong foundation that can be moved as a typical shipping container. In this way, it acts as a mobile agricultural unit. Third, a converted shipping container's internal environment is independent of environmental parameters. In an insulated environment comprising electrical lighting, soil-less cultures, and heating ventilating and air conditioning (HVAC) technologies, it is possible to grow crops in any climate. Finally, a converted shipping container offers a high yield per square meter. Using vertical farming in which five levels of shallow water hydroponic cultures of lettuce are stacked, it is possible to grow 20 times more produce per square meter in a CF than

field agriculture with corresponding yields of 1000 plants. m<sup>2</sup> [2].

such as market, labor and cheap energy availability [5].

**Figure 1***.*

**50**

*Outside of the CING, December 2017.*

CF is still a relatively new agricultural practice, and indoor farmers do not necessarily agree that this new agricultural practice is economically viable, still being considered an overhyped technology, with only 50% of container farms being profitable in the U.S. [3]. Yet CF has many different styles, with companies such as Freight Farms, Growtainers, and Cubic Farms offering similar options to grow crops in urban or remote areas [4] (**Figure 1**). According to case studies from companies like Bright Agrotech and independent reports from universities such as the University of Bonn in Germany and the Massachusetts Institute of Technology, vertical farming and CF can be economically profitable and viable depending on different economic parameters,

The concept of a modified shipping container for controlled environment agriculture is not new (**Figure 2**). Strategies using modified shipping containers with natural lighting has been made for conditions comparable to those found in New York City and Los Angeles by the University of Arizona. From these simulations, it was determined that shipping containers with transparent walls have a much lower

energy consumption than opaque and well-insulated walls (**Table 1**) [6].

 *A module for the Minimally Structured & Modular Vertical Farm, designed by Dr. Cuello from the University of Arizona (Liu, 2014).*


**Table 1.**

*Summary of annual energy consumption in kWh/m2 [6].*

From these energy values, except for growing tomatoes in a transparent wall shipping container in New York City where the well-insulated opaque wall helped reduce heat loss in a colder month, using transparent walls in a shipping container would reduce the energy needs to grow certain food crops in CF, even for Lettuce during cold months [6]. Following these findings, the CING was not modeled for its energy use, rather, design and experimental approach was chosen to test the use of natural lighting in CF in a cold climate.

## **2. Materials and methods**

## **2.1 Design of the CING**

The CING was first designed in 2013 by Bioresource engineering students at McGill University (**Figures 3** and **4**). A shipping container was purchased in 2015.

**Figure 3.** *Original design of the CING.*

#### **Figure 4.**

*Representation of the opening and closing of the outside panels.*

One of its walls and the roof were replaced by polycarbonate sheets to allow the shipping container to use natural light for growing purposes.

Only half of the 40-foot shipping container was used for growing space. The CING design includes insulating panels that can open and close (added in 2015) to benefit from natural light when available (**Figures 5** and **6**). Their opening and closing were operated by 2000-lb winches controlled by an Arduino Mega (Adafruit Industries, US).

A growth tower was designed to allow inter-canopy lighting of the crops, optimizing the use of the supplemental electrical light. The growth tower was originally designed for drip irrigation (**Figure 7**).

In 2017, the tower was converted to a nutrient film technique (NFT). A comparative tower was built using a similar inter-canopy pattern for testing the CING's performance which was placed in a research greenhouse at McGill University's Macdonald Campus (**Figure 8**).

**2.2 Energy usage**

*pictures by Thanh Jutras, 2016.*

**Figure 7.**

**53**

**Figure 6.**

One of the CING operational challenge was using minimal energy consumption. It was determined that the CING must be operational on a 30-Amp, 110 V-circuit year-round, for maximum daily energy usage of 79.2 kWh (**Table 2**) (Eq. 1).

*Original design of the CING growth tower (left), side-view (top right) and solution tank (bottom right),*

For this reason, supplemental lighting and heating are limited, but the use of natural light as a light and heat source for the growing environment was the main parameter studied to evaluate the CING's potential as an energy-efficient indoor

Under cold weather conditions, the exhaust fans were not used while in warm weather the heaters were not used resulting in maximum daily energy uses of 29.4

growing system adapted for a northern climate.

*Opening (right) and closing (left) of the CING rooftop panels.*

*DOI: http://dx.doi.org/10.5772/intechopen.96214*

*The Canadian Integrated Northern Greenhouse: A Hybrid Solution for Food Security*

Energy kWh ð Þ¼ Current Að Þ ∗ Voltage Vð Þ ∗ time hð Þ*=*1000 (1)

**Figure 5.** *Opening (left) and closing (right) of the CING insulating panels.*

*The Canadian Integrated Northern Greenhouse: A Hybrid Solution for Food Security DOI: http://dx.doi.org/10.5772/intechopen.96214*

## **Figure 6.**

*Opening (right) and closing (left) of the CING rooftop panels.*

#### **Figure 7.**

One of its walls and the roof were replaced by polycarbonate sheets to allow the

Only half of the 40-foot shipping container was used for growing space. The CING design includes insulating panels that can open and close (added in 2015) to benefit from natural light when available (**Figures 5** and **6**). Their opening and closing were operated by 2000-lb winches controlled by an Arduino Mega (Adafruit

A growth tower was designed to allow inter-canopy lighting of the crops, optimizing the use of the supplemental electrical light. The growth tower was originally

In 2017, the tower was converted to a nutrient film technique (NFT). A comparative tower was built using a similar inter-canopy pattern for testing the CING's performance which was placed in a research greenhouse at McGill University's

shipping container to use natural light for growing purposes.

*Representation of the opening and closing of the outside panels.*

*Next-Generation Greenhouses for Food Security*

Industries, US).

**Figure 5.**

**52**

**Figure 4.**

designed for drip irrigation (**Figure 7**).

*Opening (left) and closing (right) of the CING insulating panels.*

Macdonald Campus (**Figure 8**).

*Original design of the CING growth tower (left), side-view (top right) and solution tank (bottom right), pictures by Thanh Jutras, 2016.*

### **2.2 Energy usage**

One of the CING operational challenge was using minimal energy consumption. It was determined that the CING must be operational on a 30-Amp, 110 V-circuit year-round, for maximum daily energy usage of 79.2 kWh (**Table 2**) (Eq. 1).

$$\text{Energy} \, (\text{kWh}) = \text{Current} (\text{A}) \* \text{Voltage} \, (\text{V}) \* \text{time} \, (\text{h}) / 1000 \, \tag{1}$$

For this reason, supplemental lighting and heating are limited, but the use of natural light as a light and heat source for the growing environment was the main parameter studied to evaluate the CING's potential as an energy-efficient indoor growing system adapted for a northern climate.

Under cold weather conditions, the exhaust fans were not used while in warm weather the heaters were not used resulting in maximum daily energy uses of 29.4

**2.3 Thermal curtain parameters**

*DOI: http://dx.doi.org/10.5772/intechopen.96214*

**2.4 Growth experiments**

and Winter 2019 (March 1st to March 23rd).

conductivity (EC) of the Hoagland nutrient solution.

**2.5 Biological nutrient solution testing**

**2.6 Hydroponic systems parameters**

CING [7].

*2.6.1 Design*

**Figure 10.**

**55**

A thermal curtain (TEMPA 7567 D FB, Svensson, North Carolina, U.S.), allowed

The CING ran for four consecutive seasons: Spring 2018 (May 7th to June 6th), Summer 2018 (June 8th to July 2nd), Fall 2018 (December 1st to December 22nd)

Since both growing systems had two independent pumps for the right and left sides, two nutrient solutions were tested in each system. The first was a one-quarter strength Hoagland solution [8] and the second comprised a biological nutrient solution based on vermicompost leachate. This solution was continuously prepared during the experiment using 10 L vermicompost, fed a constant diet of eggshells, banana peels, coffee grounds and cardboard. By flooding the vermicompost weekly with 1 L water, the leachate was collected and diluted to match the electrical

The hydroponic growth systems were built as growing towers (**Figures 10** and **11**).

*The hydroponic growing tower system for the research greenhouse (left) and growing system in the CING (right).*

The growing systems were 6-feet high (183 cm), each containing 16 42-inch (107 cm) long tubes, where six lettuce plants can grow using NFT, resulting in 96

a transition from greenhouse mode to growth chamber mode (**Figure 9**). The thermal curtain was functional and set to open when solar irradiation was above 12 W.m<sup>2</sup> and close when irradiation went lower than the set value. This value was recommended in a previous report on the recommended operating conditions of the

*The Canadian Integrated Northern Greenhouse: A Hybrid Solution for Food Security*

#### **Figure 8.**

*Comparative growth tower in the research greenhouse, Summer 2018.*


#### **Table 2.**

*Electrical current and voltage consumption of the CING environment control system components [7].*

kWh.m<sup>2</sup> and 14.0 kWh.m<sup>2</sup> respectively. These values were obtained using only a small, representative growing area of 2 m<sup>2</sup> . The growing area of half of 40-foot shipping is 14.4 m<sup>2</sup> . More lighting, pumping capacity and air exchange would be needed if the full growing area was used.

**Figure 9.** *Inside the CING, on the right is the closed thermal curtain, Winter 2019.*

*The Canadian Integrated Northern Greenhouse: A Hybrid Solution for Food Security DOI: http://dx.doi.org/10.5772/intechopen.96214*

## **2.3 Thermal curtain parameters**

A thermal curtain (TEMPA 7567 D FB, Svensson, North Carolina, U.S.), allowed a transition from greenhouse mode to growth chamber mode (**Figure 9**). The thermal curtain was functional and set to open when solar irradiation was above 12 W.m<sup>2</sup> and close when irradiation went lower than the set value. This value was recommended in a previous report on the recommended operating conditions of the CING [7].

#### **2.4 Growth experiments**

The CING ran for four consecutive seasons: Spring 2018 (May 7th to June 6th), Summer 2018 (June 8th to July 2nd), Fall 2018 (December 1st to December 22nd) and Winter 2019 (March 1st to March 23rd).

#### **2.5 Biological nutrient solution testing**

Since both growing systems had two independent pumps for the right and left sides, two nutrient solutions were tested in each system. The first was a one-quarter strength Hoagland solution [8] and the second comprised a biological nutrient solution based on vermicompost leachate. This solution was continuously prepared during the experiment using 10 L vermicompost, fed a constant diet of eggshells, banana peels, coffee grounds and cardboard. By flooding the vermicompost weekly with 1 L water, the leachate was collected and diluted to match the electrical conductivity (EC) of the Hoagland nutrient solution.

#### **2.6 Hydroponic systems parameters**

#### *2.6.1 Design*

kWh.m<sup>2</sup> and 14.0 kWh.m<sup>2</sup> respectively. These values were obtained using only a

*Electrical current and voltage consumption of the CING environment control system components [7].*

*\*The estimated current was required for automation system and thermal curtains function.*

**Equipment AC Current (amps) Voltage (V)** Irrigation pump (4 pumps) 3.2 110 Heaters 13.8 110 LED lights 3.3 110 Automation control system 1\* 110 Motor for thermal curtains 1\* 110 Exhaust fans 2.12 110 Total 24.42 110

. More lighting, pumping capacity and air exchange would be

. The growing area of half of 40-foot

small, representative growing area of 2 m<sup>2</sup>

*Comparative growth tower in the research greenhouse, Summer 2018.*

*Next-Generation Greenhouses for Food Security*

needed if the full growing area was used.

*Inside the CING, on the right is the closed thermal curtain, Winter 2019.*

shipping is 14.4 m<sup>2</sup>

**Table 2.**

**Figure 9.**

**54**

**Figure 8.**

The hydroponic growth systems were built as growing towers (**Figures 10** and **11**). The growing systems were 6-feet high (183 cm), each containing 16 42-inch (107 cm) long tubes, where six lettuce plants can grow using NFT, resulting in 96

#### **Figure 10.**

*The hydroponic growing tower system for the research greenhouse (left) and growing system in the CING (right).*

<sup>197</sup> <sup>1</sup> <sup>μ</sup>mol/m<sup>2</sup>

<sup>50</sup> <sup>1</sup> <sup>μ</sup>mol.m<sup>2</sup>

almost constant.

*2.6.6 Crops*

**2.7 Parameters**

m<sup>2</sup> .d<sup>1</sup>

**Table 3.**

**57**

*2.7.1 Light mapping*

ity levels were not controlled.

phia, Pennsylvania) to cool the CING at 27 °C.

Winter 2019 due to lack of available seeds.

.sec<sup>1</sup>

*DOI: http://dx.doi.org/10.5772/intechopen.96214*

*2.6.5 Temperature and relative humidity*

/sec. However, we expected that lighting would sometimes be

. Lightmapping of the system was made to determine the

lower than this targeted value, and the lowest light intensity value was estimated at

*The Canadian Integrated Northern Greenhouse: A Hybrid Solution for Food Security*

amount of light achievable in both systems (Appendix A Tables A-5 to A-13) [10].

The internal CING temperature set point was 24 °C during the day and 19 °C during the night time. This temperature was maintained using an electric auxiliary heater connected to an electrical thermostat (LUX Win100, Philadelphia, Pennsylvania). For the fall and winter trials. Auxiliary electrical heating was necessary and

The internal temperature in the CING was monitored with a 12-Bit Temperature/Relative Humidity sensor ( 0.2 °C from 0° to 50 °C; 2.5% from 10% to 90%) compatible with the Hobo data logger (ONSET, Massachusetts, US). Humid-

The heating, ventilation and air-conditioning (HVAC) system were not functional for the test trials. However, exhaust fans were set on a thermostat, pulling fresh air into the CING, reducing temperature and relative humidity. A 9-inch 1100 CFM and a 16-inch 1435 CFM exhaust fan (Hessaire, Phoenix, Arizona, US) were mounted on the side wall, set on an electrical thermostat LUX Win100, Philadel-

Romaine lettuce *(Lactuca sativa)* was cultivated for the first three trials (Spring 2018, Summer 2018 and Fall 2018), and Boston lettuce (*L. sativa)* was grown in

Lightmapping of the systems was made using a handheld Li-Cor Li-250A light sensor (LI-COR Biosciences, NE, US). To get the daily light integral (DLI) (mol.

and PAR from the supplemental LED lights in the CING was 37.58 μmoles.m<sup>2</sup>

**Vermicompost Nutrient Solution Hoagland Nutrient Solution**

Assuming that a quadratic function represents PAR versus the time of day for the

**Trial pH EC (ms/m) Temp. (°C) Vol.(L) pH EC (ms/m) Temp. (°C) Vol. (L)** 1 9.1 129.9 31.7 13.8 7.9 160.2 30.3 12.2 2 6.4 140.8 26.4 15.0 6.5 146.8 26.4 15.5 3 6.9 109.5 22.6 12.9 6.6 118.4 21.9 12.4 4 5.1 146.7 24.0 14.5 4.9 84.5 23.1 11.3

*Averages of monitored nutrient solution parameters for all trials (trial 1, 2, 3 and 4 respectively correspond to*

*spring 2018, summer 2018, fall 2018 and winter 2019) in the research greenhouse.*

), the photosynthetically active radiation (PAR) obtained at the brightest moment in the day was deducted from the PAR provided by the supplemental lights provided (PAR measurement after sundown), in the greenhouse and in the CING. PAR from the supplemental HPS lights in the greenhouse was 56.69 μmoles.m<sup>2</sup>

.s<sup>1</sup>

.s<sup>1</sup> .

#### **Figure 11.** *Growing system prototype design described previously [6].*

lettuce plants total per system. Tube diameters were 2 inches (5 cm) in diameter and lettuce heads were held in 2-inch (5 cm) net pots (**Figure 11**).

#### *2.6.2 Flow in hydroponic systems*

Each side of the growing systems has an independent pump. The nutrient solution is pumped by a magnetic drive submersible water pump (EcoPlus, Eco 396, US), delivering a flow of 1500 L.h<sup>1</sup> (396 GPH), at a height of 2 m. A valve was used to control the flow in each tube, and a 1 L.min<sup>1</sup> flow ensures a 3-mm level of nutrient solution in the 5 cm tubes [9]. Four NFT tubes per experiment were tested, to ensure 0.6–1 L.min<sup>1</sup> per tube.

#### *2.6.3 Electrical conductivity (EC)*

EC was monitored with a handheld EC-meter (HM Digital Meters COM-80 Electrical Conductivity and Total Dissolved Solids Hydro Tester, Seoul, Korea). The EC was kept between 115–125 mS/m ( 2.5 mS/m) above the greenhouse's irrigation water EC. The EC was adjusted by adding greenhouse irrigation water or concentrated nutrient solution [10]. pH

The pH of both nutrient solutions was maintained between 5.50 to 7.00 (0.01). It was monitored with a handheld pH-meter (Dr. Meter PH100, China). Phosphoric acid (19.7% w/w) was used to lower pH to the desired value.

#### *2.6.4 Light*

Electrical light in the CING unit was provided by an LED installation. This comprised 10 light strips installed underneath the NFT tubes and six vertically hung light strips.When the thermal curtain was open, natural light was made available. In the Fall trial, the thermal curtain was only open when solar radiation was over 12 W/m2 [7]. The outside light was measured with a Solar Radiation Smart Sensor (ONSET, Massachusetts, US), with a range of 0 to 1280 W/m2 10 W/m2 . Light intensity to activate the thermal curtain was measured with a TSL2561 luminosity sensor, measuring Lux.

The natural lighting in the research greenhouse was supplemented with a highpressure sodium (HPS) lamp lighting system. To ensure good growth, combined lighting is approximately 17 mol/m<sup>2</sup> /day. The targeted instantaneous light intensity, measured with the LI-250A Quantum Radiometer Photometer, was estimated at

### *The Canadian Integrated Northern Greenhouse: A Hybrid Solution for Food Security DOI: http://dx.doi.org/10.5772/intechopen.96214*

<sup>197</sup> <sup>1</sup> <sup>μ</sup>mol/m<sup>2</sup> /sec. However, we expected that lighting would sometimes be lower than this targeted value, and the lowest light intensity value was estimated at <sup>50</sup> <sup>1</sup> <sup>μ</sup>mol.m<sup>2</sup> .sec<sup>1</sup> . Lightmapping of the system was made to determine the amount of light achievable in both systems (Appendix A Tables A-5 to A-13) [10].

## *2.6.5 Temperature and relative humidity*

The internal CING temperature set point was 24 °C during the day and 19 °C during the night time. This temperature was maintained using an electric auxiliary heater connected to an electrical thermostat (LUX Win100, Philadelphia, Pennsylvania). For the fall and winter trials. Auxiliary electrical heating was necessary and almost constant.

The internal temperature in the CING was monitored with a 12-Bit Temperature/Relative Humidity sensor ( 0.2 °C from 0° to 50 °C; 2.5% from 10% to 90%) compatible with the Hobo data logger (ONSET, Massachusetts, US). Humidity levels were not controlled.

The heating, ventilation and air-conditioning (HVAC) system were not functional for the test trials. However, exhaust fans were set on a thermostat, pulling fresh air into the CING, reducing temperature and relative humidity. A 9-inch 1100 CFM and a 16-inch 1435 CFM exhaust fan (Hessaire, Phoenix, Arizona, US) were mounted on the side wall, set on an electrical thermostat LUX Win100, Philadelphia, Pennsylvania) to cool the CING at 27 °C.

## *2.6.6 Crops*

lettuce plants total per system. Tube diameters were 2 inches (5 cm) in diameter

Each side of the growing systems has an independent pump. The nutrient solution is pumped by a magnetic drive submersible water pump (EcoPlus, Eco 396, US), delivering a flow of 1500 L.h<sup>1</sup> (396 GPH), at a height of 2 m. A valve was used to control the flow in each tube, and a 1 L.min<sup>1</sup> flow ensures a 3-mm level of nutrient solution in the 5 cm tubes [9]. Four NFT tubes per experiment were tested,

EC was monitored with a handheld EC-meter (HM Digital Meters COM-80 Electrical Conductivity and Total Dissolved Solids Hydro Tester, Seoul, Korea). The EC was kept between 115–125 mS/m ( 2.5 mS/m) above the greenhouse's irrigation water EC. The EC was adjusted by adding greenhouse irrigation water or concen-

The pH of both nutrient solutions was maintained between 5.50 to 7.00 (0.01). It was monitored with a handheld pH-meter (Dr. Meter PH100, China). Phosphoric

Electrical light in the CING unit was provided by an LED installation. This comprised 10 light strips installed underneath the NFT tubes and six vertically hung light strips.When the thermal curtain was open, natural light was made available. In the Fall trial, the thermal curtain was only open when solar radiation was over 12 W/m2 [7]. The outside light was measured with a Solar Radiation Smart Sensor (ONSET, Massa-

the thermal curtain was measured with a TSL2561 luminosity sensor, measuring Lux. The natural lighting in the research greenhouse was supplemented with a highpressure sodium (HPS) lamp lighting system. To ensure good growth, combined

measured with the LI-250A Quantum Radiometer Photometer, was estimated at

. Light intensity to activate

/day. The targeted instantaneous light intensity,

acid (19.7% w/w) was used to lower pH to the desired value.

chusetts, US), with a range of 0 to 1280 W/m2 10 W/m2

and lettuce heads were held in 2-inch (5 cm) net pots (**Figure 11**).

*2.6.2 Flow in hydroponic systems*

*Growing system prototype design described previously [6].*

*Next-Generation Greenhouses for Food Security*

**Figure 11.**

to ensure 0.6–1 L.min<sup>1</sup> per tube.

*2.6.3 Electrical conductivity (EC)*

trated nutrient solution [10]. pH

lighting is approximately 17 mol/m<sup>2</sup>

*2.6.4 Light*

**56**

Romaine lettuce *(Lactuca sativa)* was cultivated for the first three trials (Spring 2018, Summer 2018 and Fall 2018), and Boston lettuce (*L. sativa)* was grown in Winter 2019 due to lack of available seeds.

## **2.7 Parameters**

## *2.7.1 Light mapping*

Lightmapping of the systems was made using a handheld Li-Cor Li-250A light sensor (LI-COR Biosciences, NE, US). To get the daily light integral (DLI) (mol. m<sup>2</sup> .d<sup>1</sup> ), the photosynthetically active radiation (PAR) obtained at the brightest moment in the day was deducted from the PAR provided by the supplemental lights provided (PAR measurement after sundown), in the greenhouse and in the CING. PAR from the supplemental HPS lights in the greenhouse was 56.69 μmoles.m<sup>2</sup> .s<sup>1</sup> and PAR from the supplemental LED lights in the CING was 37.58 μmoles.m<sup>2</sup> .s<sup>1</sup> . Assuming that a quadratic function represents PAR versus the time of day for the


#### **Table 3.**

*Averages of monitored nutrient solution parameters for all trials (trial 1, 2, 3 and 4 respectively correspond to spring 2018, summer 2018, fall 2018 and winter 2019) in the research greenhouse.*


**Table 4.**

*Averages of monitored nutrient solution parameters for all trials (trial 1, 2, 3 and 4 respectively correspond to spring 2018, summer 2018, fall 2018 and winter 2019) in the CING.*

length of the specified day, with the measured PAR value at its highest value during daytime, it was possible to evaluate the maximum daily light integral from the Sunlight for a specific trial. By adding the DLI from the sun with the DLI of the supplemental light, a total maximum DLI was obtained.

**4. Discussion**

**Figure 12.**

**59**

*Average fresh mass (g) of lettuce for all treatments at harvest.*

**Table 5.**

**4.1 Summary of results**

common growing environment.

**4.2 Environmental and growing parameters differences**

*Vermicompost (V) and Hoagland (H) nutrient solutions at harvest.*

*DOI: http://dx.doi.org/10.5772/intechopen.96214*

**Season test Run Spring Summer**

*The Canadian Integrated Northern Greenhouse: A Hybrid Solution for Food Security*

**Growth environment GH CING GH CING** Growth environment GH CING GH CING Treatment V H V H V H V H Average fresh mass of lettuce (g) 2.51 17.54 0.99 0.97 4.38 23.40 2.07 16.79 S.E. 0.17 2.15 0.06 0.08 0.34 2.15 0.21 2.70

*Average fresh mass with standard error (S.E.) for all treatments, greenhouse (GH) and CING, with*

Plants grown in the research greenhouse with the Hoagland nutrient solution had the highest fresh and dry mass for all tests (**Figure 12**). Of all the CING trials, the fresh and dry mass of lettuce grown in the CING with the Hoagland nutrient solution during the Winter trial was the highest (**Figure 13**). The Vermicompost nutrient solution had lower fresh and dry mass compared to the Hoagland in a

Because of the climate difference between trials, the growth environment differed greatly in the CING. The lighting cycle for the Spring trial was 12 h day: 12 h night, the thermal curtain was active and roof panels were closed. In addition, pH was not controlled for this trial. The lighting cycle for the Summer trial was 12 h day: 12 h night, the thermal curtain was active and only one roof panel was open (**Figure 14**). The lighting cycle for the Fall trial was 16 h day: 8 h night, the thermal curtain was active and only one roof panel was open. The lighting cycle for the Winter trial was 24 h day 0 h night, the thermal curtain was not active and only one roof panel was open.

For the Summer trial, PAR was measured on June 19th, 2018 under clear skies, assuming a 16-h day and 8-h night during the entirety of this trial. DLI in the greenhouse was evaluated at 29.4 mol/m<sup>2</sup> /d and DLI in the CING was evaluated at 20.9 mol.m<sup>2</sup> .d<sup>1</sup> . For the Fall trial, PAR was measured on December 20th, 2018 under clear skies, assuming a day length of 8 h 50 min during this trial. DLI in the Fall in the greenhouse was evaluated at 5.1 mol.m<sup>2</sup> .d<sup>1</sup> and 7.61 mol.m<sup>2</sup> .d<sup>1</sup> in the CING. For the Winter trial, PAR was measured on March 19th, 2019 under clear skies, with an average daytime of 12 h, assuming the same PAR from supplemental lighting in the greenhouse and the CING from previous experiments. DLI in Winter in the greenhouse was evaluated at 18.0 mol.m<sup>2</sup> .d<sup>1</sup> and in the CING was evaluated at 9.3 mol.m<sup>2</sup> .d<sup>1</sup> . PAR mapping of the systems is available in Appendix A.

#### *2.7.2 Monitoring of systems*

The EC, pH, temperature and volume of the nutrient solutions for both systems were measured manually. Full monitoring data is available in the appendices and mean values for each trial are available in **Tables 3** and **4**.

#### **2.8 Data analysis**

Independent samples t-tests were performed using Excel to assess the statistical difference of the yields of fresh and dry masses of lettuce obtained in between growing environment for each trial.



*The Canadian Integrated Northern Greenhouse: A Hybrid Solution for Food Security DOI: http://dx.doi.org/10.5772/intechopen.96214*


**Table 5.**

length of the specified day, with the measured PAR value at its highest value during daytime, it was possible to evaluate the maximum daily light integral from the Sunlight for a specific trial. By adding the DLI from the sun with the DLI of the

*Averages of monitored nutrient solution parameters for all trials (trial 1, 2, 3 and 4 respectively correspond to*

For the Summer trial, PAR was measured on June 19th, 2018 under clear skies,

under clear skies, assuming a day length of 8 h 50 min during this trial. DLI in the

CING. For the Winter trial, PAR was measured on March 19th, 2019 under clear skies, with an average daytime of 12 h, assuming the same PAR from supplemental lighting in the greenhouse and the CING from previous experiments. DLI in Winter

The EC, pH, temperature and volume of the nutrient solutions for both systems were measured manually. Full monitoring data is available in the appendices and

Independent samples t-tests were performed using Excel to assess the statistical

difference of the yields of fresh and dry masses of lettuce obtained in between

**Growth environment GH CING GH CING** Treatment V H V H V H V H Average fresh mass of lettuce (g) 0.82 33.63 0.64 4.60 4.81 53.25 1.86 7.41 S.E. 0.11 5.05 0.14 1.33 0.16 4.75 0.27 0.70

**Season test Run Spring Summer**

Season test Run **Fall Winter**

. For the Fall trial, PAR was measured on December 20th, 2018

. PAR mapping of the systems is available in Appendix A.

/d and DLI in the CING was evaluated at

.d<sup>1</sup> and 7.61 mol.m<sup>2</sup>

.d<sup>1</sup> and in the CING was evalu-

.d<sup>1</sup> in the

assuming a 16-h day and 8-h night during the entirety of this trial. DLI in the

**Vermicompost Nutrient Solution Hoagland Nutrient Solution**

**Trial pH EC (ms/m) Temp. (°C) Vol. (L) pH EC (ms/m) Temp. (°C) Vol. (L)** 1 8.9 117.2 20.0 14.9 8.0 119.5 19.5 15.1 2 6.4 128.5 26.3 22.0 6.3 132.3 26.0 23.5 3 6.9 68.2 10.7 10.3 6.6 128.2 10.2 18.7 4 7.4 123.2 19.6 16.3 7.3 114.5 19.3 14.1

supplemental light, a total maximum DLI was obtained.

*spring 2018, summer 2018, fall 2018 and winter 2019) in the CING.*

Fall in the greenhouse was evaluated at 5.1 mol.m<sup>2</sup>

in the greenhouse was evaluated at 18.0 mol.m<sup>2</sup>

mean values for each trial are available in **Tables 3** and **4**.

.d<sup>1</sup>

growing environment for each trial.

greenhouse was evaluated at 29.4 mol/m<sup>2</sup>

*Next-Generation Greenhouses for Food Security*

.d<sup>1</sup>

20.9 mol.m<sup>2</sup>

**Table 4.**

ated at 9.3 mol.m<sup>2</sup>

**2.8 Data analysis**

**3. Results**

**58**

*2.7.2 Monitoring of systems*

*Average fresh mass with standard error (S.E.) for all treatments, greenhouse (GH) and CING, with Vermicompost (V) and Hoagland (H) nutrient solutions at harvest.*

## **4. Discussion**

### **4.1 Summary of results**

Plants grown in the research greenhouse with the Hoagland nutrient solution had the highest fresh and dry mass for all tests (**Figure 12**). Of all the CING trials, the fresh and dry mass of lettuce grown in the CING with the Hoagland nutrient solution during the Winter trial was the highest (**Figure 13**). The Vermicompost nutrient solution had lower fresh and dry mass compared to the Hoagland in a common growing environment.

#### **4.2 Environmental and growing parameters differences**

Because of the climate difference between trials, the growth environment differed greatly in the CING. The lighting cycle for the Spring trial was 12 h day: 12 h night, the thermal curtain was active and roof panels were closed. In addition, pH was not controlled for this trial. The lighting cycle for the Summer trial was 12 h day: 12 h night, the thermal curtain was active and only one roof panel was open (**Figure 14**). The lighting cycle for the Fall trial was 16 h day: 8 h night, the thermal curtain was active and only one roof panel was open. The lighting cycle for the Winter trial was 24 h day 0 h night, the thermal curtain was not active and only one roof panel was open.

**Figure 12.** *Average fresh mass (g) of lettuce for all treatments at harvest.*

lettuce cultivation [10]. The Hoagland nutrient solution for the Winter trial was added at the beginning of the trial but not during; this explains the lower EC

*The Canadian Integrated Northern Greenhouse: A Hybrid Solution for Food Security*

The Fall and Winter trials were the first cold climate trials undertaken in the CING unit. The comparison of the average conditions in the CING during both trial

For the Fall trial, the thermal curtain was set to open and close according to outdoor solar radiation. For the Winter trial, the thermal curtain remained closed,

the Fall trial. The average inside temperature in Fall was below the 15 °C

The curtain has an 80% shading level in diffused light PAR. The 20% of diffused light combined with the light from one opened roof panel, the constant supplemental lighting and the longer days allowed for greater DLI in the Winter Trial than

recommended temperature for lettuce production [10]. This environmental difference explains the major difference in crop yield from the two cold conditions tests.

The thermal curtain usage changed the internal conditions of the CING. By comparing a set of days during both trials with similar outdoor temperature changes and environmental conditions, it is possible to better assess the impact of the thermal curtain. From December 10th to 12th 2018, the average outdoor and indoor temperatures were respectively, 7.6 °C and 12.3 °C. From March 4th to 6th 2019, the average outdoor and indoor temperatures were respectively, 8.2 °C and 7.5 °C. Considering the thermal properties of the polycarbonate sheet, the thermal curtain and the insulating layer of air kept in between the thermal curtain and the polycarbonate sheet, with a temperature gradient of 15 °C from the inside and the outside of the CING the thermal heat loss from the window would be 17 Watts with the curtain closed, and 282 Watts with the curtain open. See the full heat transfer

Using the thermal curtain, the solar heat gain (SHG) to the CING was reduced, proportionally to the sunlight blocked, 80% [11]. This difference in SHG can be linked to the more stable temperature during the day, noticeable in **Figure 15** during the Fall trial cold days testing. However, during the Winter trial, with the thermal curtain constantly closed, the inside temperature was more dependent on the outside temperature as observed in **Figure 16** for a 3 days comparison with

This trend can be observed when comparing the relationship between the indoor and outdoor temperatures, during the 3 days comparison in **Figures 17** and **18** and the whole experiment data in **Figures 19** and **20**. Whereas the R2 = 0.0656 for the

> **Average Inside Temperature (°C)**

Fall 2018 3.9 11.0 7.6 0.97 Winter 2019 2.4 14.8 9.3 16.79

*Summary of Table 3, Table 4 and Table 5 for cold condition trials of the CING.*

**Approximate DLI (mol.m<sup>2</sup>**

**.d<sup>1</sup> )** **Average Fresh Mass (g)**

observed in the greenhouse for the Winter trial.

*DOI: http://dx.doi.org/10.5772/intechopen.96214*

is available in the next table (**Table 6**).

to help reduce thermal heat losses.

**4.3 Cold weather trials**

*4.3.1 Thermal curtain*

rate calculation in Appendix A.

similar average temperatures.

**Trial Average Outside**

**Table 6.**

**61**

**Temperature (°C)**

**Figure 13.** *Lettuce grown in the CING before harvest, Winter 2019.*

**Figure 14.** *Inside the CING, on top left is an opened roof panel, Summer 2018.*

During the Spring trial, the pH in the vermicompost nutrient solution was over 8.5, pH was not controlled during the Spring trial and this may have limited nutrient availability and uptake.

During the Spring, Summer and Fall trials, plants in the CING grew very little when compared to plants grown in the greenhouse. During the Summer trial, the average temperature was slightly higher (25.4 °C) than the suggested temperature for lettuce growth (25 °C), and in the Fall the average temperature was 11 °C, which is lower than the recommended minimum (15 °C) for lettuce growth. Relative humidity for all trials ranged between of 50 to 70%, which is recommended for

lettuce cultivation [10]. The Hoagland nutrient solution for the Winter trial was added at the beginning of the trial but not during; this explains the lower EC observed in the greenhouse for the Winter trial.

## **4.3 Cold weather trials**

The Fall and Winter trials were the first cold climate trials undertaken in the CING unit. The comparison of the average conditions in the CING during both trial is available in the next table (**Table 6**).

For the Fall trial, the thermal curtain was set to open and close according to outdoor solar radiation. For the Winter trial, the thermal curtain remained closed, to help reduce thermal heat losses.

The curtain has an 80% shading level in diffused light PAR. The 20% of diffused light combined with the light from one opened roof panel, the constant supplemental lighting and the longer days allowed for greater DLI in the Winter Trial than the Fall trial. The average inside temperature in Fall was below the 15 °C recommended temperature for lettuce production [10]. This environmental difference explains the major difference in crop yield from the two cold conditions tests.

#### *4.3.1 Thermal curtain*

The thermal curtain usage changed the internal conditions of the CING. By comparing a set of days during both trials with similar outdoor temperature changes and environmental conditions, it is possible to better assess the impact of the thermal curtain. From December 10th to 12th 2018, the average outdoor and indoor temperatures were respectively, 7.6 °C and 12.3 °C. From March 4th to 6th 2019, the average outdoor and indoor temperatures were respectively, 8.2 °C and 7.5 °C.

Considering the thermal properties of the polycarbonate sheet, the thermal curtain and the insulating layer of air kept in between the thermal curtain and the polycarbonate sheet, with a temperature gradient of 15 °C from the inside and the outside of the CING the thermal heat loss from the window would be 17 Watts with the curtain closed, and 282 Watts with the curtain open. See the full heat transfer rate calculation in Appendix A.

Using the thermal curtain, the solar heat gain (SHG) to the CING was reduced, proportionally to the sunlight blocked, 80% [11]. This difference in SHG can be linked to the more stable temperature during the day, noticeable in **Figure 15** during the Fall trial cold days testing. However, during the Winter trial, with the thermal curtain constantly closed, the inside temperature was more dependent on the outside temperature as observed in **Figure 16** for a 3 days comparison with similar average temperatures.

This trend can be observed when comparing the relationship between the indoor and outdoor temperatures, during the 3 days comparison in **Figures 17** and **18** and the whole experiment data in **Figures 19** and **20**. Whereas the R2 = 0.0656 for the


**Table 6.**

*Summary of Table 3, Table 4 and Table 5 for cold condition trials of the CING.*

During the Spring trial, the pH in the vermicompost nutrient solution was over 8.5, pH was not controlled during the Spring trial and this may have limited nutrient

During the Spring, Summer and Fall trials, plants in the CING grew very little when compared to plants grown in the greenhouse. During the Summer trial, the average temperature was slightly higher (25.4 °C) than the suggested temperature for lettuce growth (25 °C), and in the Fall the average temperature was 11 °C, which is lower than the recommended minimum (15 °C) for lettuce growth. Relative humidity for all trials ranged between of 50 to 70%, which is recommended for

availability and uptake.

*Inside the CING, on top left is an opened roof panel, Summer 2018.*

*Lettuce grown in the CING before harvest, Winter 2019.*

*Next-Generation Greenhouses for Food Security*

**Figure 14.**

**60**

**Figure 13.**

**Figure 15.**

*Outside temperature, inside temperature and outside PAR of the CING, December 10th to December 12th 2018.*

#### **Figure 16.**

*Outside temperature, inside temperature and outside PAR of the CING, march 4th to march 6th 2019.*

Fall trial and R2 = 0.702 for the Winter trial during the 3 days comparison and R2 = 0.3114 for the Fall trial and R2 = 0.5741 for the Winter trial during the full trials.

#### *4.3.2 Energy usage*

Considering that the average cold and warm weather maximum energy requirements of the CING are approximately 21.7 kWh.m<sup>2</sup> , the maximum yearly energy use of the CING would be 7920 kWh.m<sup>2</sup> . This is still considerably higher than the modified shipping container described by The University of Arizona and higher than the 711.91 kWh.m<sup>2</sup> average for 164 greenhouses occupying a total of 16444 m<sup>2</sup> operated by Cornell University's Agricultural Experiment Station in New York [6].

The use of the thermal curtain showed an effect on inside temperature, but the extra sunlight SHG did not provide enough light and heat to achieve growing parameters during the Fall trial. The use of electrical lights and heating however provided enough light and heat to achieve growing parameters during the Winter trial.

Heating was almost constant in cold conditions, with an average indoor temperature for the Winter trial of 14.8 °C. Heating was the most energy-intensive parameter of the CING, representing 62% of the maximum daily energy requirement, but the achieved temperature was still lower than the recommended temperature for

*Temperature inside vs. temperature outside of CING, fall trial, December 1st to December 22nd 2018.*

*Temperature inside vs. temperature outside of CING, fall trial, December 10th to 12th 2018.*

*The Canadian Integrated Northern Greenhouse: A Hybrid Solution for Food Security*

*DOI: http://dx.doi.org/10.5772/intechopen.96214*

*Temperature inside vs. temperature outside of CING, winter trial, march 4th to 6th 2019.*

lettuce growth [10].

**Figure 17.**

**Figure 18.**

**Figure 19.**

**63**

*The Canadian Integrated Northern Greenhouse: A Hybrid Solution for Food Security DOI: http://dx.doi.org/10.5772/intechopen.96214*

**Figure 17.** *Temperature inside vs. temperature outside of CING, fall trial, December 10th to 12th 2018.*

**Figure 18.** *Temperature inside vs. temperature outside of CING, winter trial, march 4th to 6th 2019.*

**Figure 19.** *Temperature inside vs. temperature outside of CING, fall trial, December 1st to December 22nd 2018.*

Heating was almost constant in cold conditions, with an average indoor temperature for the Winter trial of 14.8 °C. Heating was the most energy-intensive parameter of the CING, representing 62% of the maximum daily energy requirement, but the achieved temperature was still lower than the recommended temperature for lettuce growth [10].

Fall trial and R2 = 0.702 for the Winter trial during the 3 days comparison and R2 = 0.3114 for the Fall trial and R2 = 0.5741 for the Winter trial during the full trials.

*Outside temperature, inside temperature and outside PAR of the CING, march 4th to march 6th 2019.*

*Outside temperature, inside temperature and outside PAR of the CING, December 10th to December 12th*

ments of the CING are approximately 21.7 kWh.m<sup>2</sup>

use of the CING would be 7920 kWh.m<sup>2</sup>

Considering that the average cold and warm weather maximum energy require-

modified shipping container described by The University of Arizona and higher than the 711.91 kWh.m<sup>2</sup> average for 164 greenhouses occupying a total of 16444 m<sup>2</sup> operated by Cornell University's Agricultural Experiment Station in New York [6]. The use of the thermal curtain showed an effect on inside temperature, but the

extra sunlight SHG did not provide enough light and heat to achieve growing parameters during the Fall trial. The use of electrical lights and heating however provided enough light and heat to achieve growing parameters during the Winter

, the maximum yearly energy

. This is still considerably higher than the

*4.3.2 Energy usage*

**Figure 16.**

**Figure 15.**

*Next-Generation Greenhouses for Food Security*

*2018.*

trial.

**62**

The dry mass of lettuce grown in the winter achieved 72% of the average fresh mass of lettuce grown at the same time in the greenhouse. In addition, the lettuce grown in the CING during the winter had the highest fresh and dry mass when compared to the other trials in the CING unit when using Hoagland nutrient solution. The vermicompost nutrient solution allowed for lettuce growth but at a much lower yield for all trials likely due to nitrogen deficiency. Continuous supplemental LED light provided the best results for lettuce growth in the CING. The thermal curtain opening according to an outdoor solar radiation threshold did allow for more light and heat in the CING unit, reducing the correlation of inside and outside

*The Canadian Integrated Northern Greenhouse: A Hybrid Solution for Food Security*

The combination of natural and supplemental light in CF has the potential to reduce energy needs linked to lighting. However, heat loss analyses must be made to evaluate the energy efficiency of a single transparent wall or part of a single

Secondly, trials performed in the CING only used a small part of the growing space. To decrease the energy needs per growth surface another hydroponic configuration could be used. Container farms often use stacked shallow water cultures to grow leafy greens, which allows the highest density of crop production. Considering the full growing area of the CING represents half of a 40-foot shipping

growth, thus reducing energy requirements per square meter of production. More lighting and air exchange would be needed to use all the growing areas, and heating energy requirements might be reduced by the addition of supplemental lighting. Modifying the CING for better space usage could reduce energy demands per unit

Thirdly, a recommended modification to the CING unit would be better environmental control, with a functional HVAC system; to increase the temperature and humidity control of the CING. Plus a larger thermal mass of the northern wall of the CING; to reduce the heating requirements by increasing the passive heating of the CING [12]. A complete heat exchange simulation of the CING would be necessary

, 75% of this the growing area or 10.8 m<sup>2</sup> could be used for plant

transparent wall of a container farm in a northern Canada climate.

to compare its performance as a northern growing unit.

temperature, under cold outdoor conditions.

*DOI: http://dx.doi.org/10.5772/intechopen.96214*

**5.1 Recommendations**

container or 14.4 m<sup>2</sup>

of crops produced.

**65**

**Figure 20.**

*Temperature inside vs. temperature outside of CING, winter trial, march 1st to march 23rd 2019.*

#### *4.3.3 Other considerations*

The CING structure was strong enough to withstand the weight of snow accumulation.

Interestingly, we observed that the highest lettuce yield for the CING-grown plants was during the Winter trial. This demonstrates the potential of winter growth within the CING.

The vermicompost-based nutrient solution has seen an improvement from the beginning of the experiments but the nutrient profile is not yet complete and provides lower lettuce yields than the Hoagland nutrient solution.

#### **4.4 Feasibility of the CING**

Inspired by container farming, the CING was designed to operate in a cold and warm climate, exemplified by the short growing season in northern Canada. The environmental conditions surrounding the CING had a major impact on its interior environment, but the ability to insulate the CING unit using a thermal curtain helped manage heat and keep stable growing conditions.

If CF can successfully allow for food crop growth in a cold climate as demonstrated by these CING trials, the prototype cannot yet be considered viable as heating demands are too high and environmental control is not adequate. However, the use of natural light has made it possible to cultivate plants in this growing environment with minimal supplemental lighting. The main issue with the CING is its capacity to keep a desired internal temperature under outdoor cold conditions. The opening of the thermal curtain did increase light intensity and allowed for a higher solar heat gain. Performance of the CING in terms of biomass production was higher when the thermal curtain remained closed during the Winter, but this result is mainly caused by the average inside temperature and DLI to be higher during this trial.

#### **5. Conclusion**

The CING unit was able to successfully grow lettuce plants in a cold climate during the Winter trial but energy demands were still very high because of heating.

#### *The Canadian Integrated Northern Greenhouse: A Hybrid Solution for Food Security DOI: http://dx.doi.org/10.5772/intechopen.96214*

The dry mass of lettuce grown in the winter achieved 72% of the average fresh mass of lettuce grown at the same time in the greenhouse. In addition, the lettuce grown in the CING during the winter had the highest fresh and dry mass when compared to the other trials in the CING unit when using Hoagland nutrient solution. The vermicompost nutrient solution allowed for lettuce growth but at a much lower yield for all trials likely due to nitrogen deficiency. Continuous supplemental LED light provided the best results for lettuce growth in the CING. The thermal curtain opening according to an outdoor solar radiation threshold did allow for more light and heat in the CING unit, reducing the correlation of inside and outside temperature, under cold outdoor conditions.

## **5.1 Recommendations**

*4.3.3 Other considerations*

*Next-Generation Greenhouses for Food Security*

growth within the CING.

**4.4 Feasibility of the CING**

during this trial.

**5. Conclusion**

**64**

mulation.

**Figure 20.**

The CING structure was strong enough to withstand the weight of snow accu-

*Temperature inside vs. temperature outside of CING, winter trial, march 1st to march 23rd 2019.*

Interestingly, we observed that the highest lettuce yield for the CING-grown plants was during the Winter trial. This demonstrates the potential of winter

The vermicompost-based nutrient solution has seen an improvement from the beginning of the experiments but the nutrient profile is not yet complete and pro-

Inspired by container farming, the CING was designed to operate in a cold and warm climate, exemplified by the short growing season in northern Canada. The environmental conditions surrounding the CING had a major impact on its interior environment, but the ability to insulate the CING unit using a thermal curtain

If CF can successfully allow for food crop growth in a cold climate as demonstrated by these CING trials, the prototype cannot yet be considered viable as heating demands are too high and environmental control is not adequate. However, the use of natural light has made it possible to cultivate plants in this growing environment with minimal supplemental lighting. The main issue with the CING is its capacity to keep a desired internal temperature under outdoor cold conditions. The opening of the thermal curtain did increase light intensity and allowed for a higher solar heat gain. Performance of the CING in terms of biomass production was higher when the thermal curtain remained closed during the Winter, but this result is mainly caused by the average inside temperature and DLI to be higher

The CING unit was able to successfully grow lettuce plants in a cold climate during the Winter trial but energy demands were still very high because of heating.

vides lower lettuce yields than the Hoagland nutrient solution.

helped manage heat and keep stable growing conditions.

The combination of natural and supplemental light in CF has the potential to reduce energy needs linked to lighting. However, heat loss analyses must be made to evaluate the energy efficiency of a single transparent wall or part of a single transparent wall of a container farm in a northern Canada climate.

Secondly, trials performed in the CING only used a small part of the growing space. To decrease the energy needs per growth surface another hydroponic configuration could be used. Container farms often use stacked shallow water cultures to grow leafy greens, which allows the highest density of crop production. Considering the full growing area of the CING represents half of a 40-foot shipping container or 14.4 m<sup>2</sup> , 75% of this the growing area or 10.8 m<sup>2</sup> could be used for plant growth, thus reducing energy requirements per square meter of production. More lighting and air exchange would be needed to use all the growing areas, and heating energy requirements might be reduced by the addition of supplemental lighting. Modifying the CING for better space usage could reduce energy demands per unit of crops produced.

Thirdly, a recommended modification to the CING unit would be better environmental control, with a functional HVAC system; to increase the temperature and humidity control of the CING. Plus a larger thermal mass of the northern wall of the CING; to reduce the heating requirements by increasing the passive heating of the CING [12]. A complete heat exchange simulation of the CING would be necessary to compare its performance as a northern growing unit.


**Table A-1.** *Monitoring of pH, EC, temperature and volume of nutrient solution for the Spring trial.*

**GREENHOUSE** **Hoagland Nutrient Solution**

**Vermicompost**

 **Nutrient Solution**

**Vermicompost**

**67**

**DATE**

 **pH EC**

**(ms/m)**

2018-06-12

2018-06-13

2018-06-19 2018-06-21

2018-06-26

2018-06-28

**AVERAGE** 6.4 140.8

**Table A-2.**

*Monitoring*

 *of pH, EC, temperature*

 *and volume of nutrient solution for the Summer trial.*

 26.4

 3.7

 15.0 6.5 146.8

 26.4

 3.8

 15.5

6.4 128.5

 26.3

 5.4

 22.0 6.3 132.3

 26.0

 5.8

 23.5

 5.9 111.0

 6.2 142.0

 25.2

 3.8 4.0

 16.3 5.9 109.0

 15.2 6.2 141.0

 24.9

 4.0 4.5

 18.3

6.0 111.0

 26.9

 6.3

 25.4 5.9 109.0

 16.3

6.3 133.0

 27.1

 4.8

 19.3 6.1 136.0

 26.3

 26.5

 7.8

 31.5

 5.5

 22.4

 6.1 131.0

4.0

 16.3 6.1 135.0

4.0

 16.3

6.1 134.0

5.5

 22.4 5.9 136.0

 6.9 144.0

 27.1

 4.3

 17.3 7.1 158.0

 7.1 176.0

 26.8

 2.5

 10.2 7.3 191.0

 27.3

 27.1

 4.6

 18.7

6.8 131.0 6.2 135.0

 27.0

 5.0

 20.3 6.8 141.0

6.4 134.0

 2.0

 8.1

6.8 127.0

 24.0

 5.5

 22.4 6.7 138.0

 24.0

 27.0

 4.9 5.3

6.0

 24.4

 21.3

 19.9

 5.3

 21.3

*The Canadian Integrated Northern Greenhouse: A Hybrid Solution for Food Security*

**n (°C)**

**(inch)**

**(L)**

**(ms/**

**n (°C)**

**(inch)**

**(L)**

**(°C)**

**(ms/**

**n (°C)**

**(inch)**

**(L)**

**(ms/**

**n (°C)**

**(inch)**

**(L)**

**(°C)**

**m)**

**m)**

**m)**

 **Nutrient Solution**

**T\_solutio**

**Level**

**Volume**

**pH EC**

**T\_solutio**

**Level**

**Volume**

**T\_amb**

**pH EC**

**T\_solutio**

**Level**

**Volume**

**pH EC**

**T\_solutio**

**Level**

**Volume**

**T\_amb**

**CING**

*DOI: http://dx.doi.org/10.5772/intechopen.96214*

**Hoagland Nutrient Solution**

**A.1** 

**Monitoring**

 **of systems**

**Appendix**

 **A**



#### *The Canadian Integrated Northern Greenhouse: A Hybrid Solution for Food Security DOI: http://dx.doi.org/10.5772/intechopen.96214*

**Appendix**

**A.1** 

**66**

**Monitoring**

 **of systems** **GREENHOUSE** **Hoagland Nutrient Solution**

**Vermicompost**

 **Nutrient Solution**

**Vermicompost**

**DATE**

 **pH EC**

**T\_solution**

**Level**

**Volume**

**pH EC**

**T\_solution**

**Level**

**Volume**

**T\_amb**

**pH EC**

**T\_solution**

**Level**

**Volume**

**pH EC**

**T\_solutio**

**Level**

**Volume**

**T\_amb**

*Next-Generation Greenhouses for Food Security*

**(ms/**

**(°C)**

**(inch)**

**(L)**

**(ms/**

**(°C)**

**(inch)**

**(L)**

**(°C)**

**(ms/**

**(°C)**

**(inch)**

**(L)**

**(ms/**

**n (°C)**

**(inch)**

**(L)**

**(°C)**

**m)**

7.5 131.0 7.5 134.2

7.9 126.0 7.9 126.0

 13.0

 13.0

 21.4

 21.0

27.0

25.0

13.0

13.0

**m)**

**m)**

7.5 150.0 7.3 154.5

7.7 160.0 7.7 160.0

 32.0

 26.0

 34.0

 27.0

 32.0

 31.0

 26.0

 31.0

 3.5

 14.2

 27.0 9.1 132.0

 20.0

 3.5

 14.2 8.1 102.0

 20.0

 4.0

 16.3

 22.0

 4.0

 16.3

 28.0 9.1 135.0

 24.0

 3.5

 14.2 7.7 100.0

 22.0

 5.0

 20.3

 20.0

 2.2

 8.9

 29.0 9.0 135.0

 3.5

 14.2

 27.0 9.1 126.0

 24.0

 19.0

 3.4

 13.8 8.3 129.0

 18.0

 3.8

 15.4

 22.0

 3.6

 14.6 8.4 123.0

 23.5

 4.3

 17.3

 28.0

 3.4

 13.8

 28.0 9.0 116.0

 21.0

 3.9

 15.9 8.3 127.0

 21.0

 3.8

 15.4

 22.0

 3.5

 14.2

 35.0 8.9 112.0

 14.0

 3.8

 15.4 8.1 126.0

 14.0

 3.8

 15.4

 22.0

 4.0

 16.3

 28.0 9.0 109.0

 32.0

 33.0

 36.2

28.5 8.2 87.7 31.0 8.3 89.2 34.0 8.7 81.0 34.0 8.7 81.0

 21.1

 22.3

 13.0

 13.0

 18.0

 4.0

 16.3 8.1 124.0

 18.0

 4.0

 16.3

 20.0

**m)**

2018-05-08

2018-05-09

2018-05-11

2018-05-14

2018-05-15

2018-05-16

2018-05-17

2018-05-18

2018-05-21

2018-05-22

2018-05-23

2018-05-24

2018-05-25

2018-05-28

2018-05-29

**AVERAGE** 9.1 129.9

**Table A-1.**

*Monitoring*

 *of pH, EC, temperature*

 *and volume of nutrient solution for the Spring trial.*

 141.0

 32.0

 31.7

 3.4

 13.8 7.9 160.2

 4.0

 16.3

 121.0

 28.0

 30.3

 3.0

 12.2

 29.0 8.9 117.2

 20.0

 3.7

 14.9 8.0 119.5

 19.5

 3.7

 15.1

 22.0

 2.0

 8.1

 23.0

 136.0

 9.0 131.0

 157.0

 32.0

 3.2 4.0

 16.3 7.7 110.0

 13.0 7.9 211.0

 147.0

 32.0

 3.5

 14.2

 162.0

 30.0

 26.0

 1.5 3.0

 12.2

 6.1

 26.0 9.2 145.0

 2.5

 10.2

 28.0

 142.0

 24.0

 26.0

> 131.0

 3.4 4.3

 17.3

 115.0 115.0

 13.8 8.3 110.0

 24.0

 1.3 4.5

 18.3

 24.0

 5.3

 26.0

 3.3

 13.2

 105.0

 24.0

 2.8

 11.2

 24.0

 9.2 140.0

 32.0

 3.5

 14.2 8.3 143.0

 9.2 131.0

 28.0

 3.7

 15.0 8.3 133.0

 9.3 153.0

 32.0

 2.8

 11.4 8.3 216.0

 9.3 134.0

 33.0

 3.5

 14.2 8.2 172.0

 9.1 141.0

 27.0

 2.9

 11.8 7.9 183.0

 9.2 134.0

 35.0

 3.0

 12.2 7.9 168.0

 9.7 123.0

 26.0

 3.3

 13.2 7.7 160.0

 9.2 100.0

 32.0

 9.0 100.0

 32.0

 8.4 106.7

 34.6

 8.4 110.0

 36.2

 **Nutrient Solution**

**CING**

**Hoagland Nutrient Solution**

 **A**



**GREENHOUSE**

**69**

**Vermicompost Nutrient Solution**

**DATE**

 **pH Tds**

**EC**

**T\_solutio**

**Level**

**Volume**

**pH Tds**

**EC**

**T\_solutio**

**Level**

**Volume**

**T\_amb**

**pH Tds**

**EC**

**T\_solutio**

**Level**

**Volume**

**pH Tds**

**EC**

**T\_solutio**

**Level**

**Volume**

**T\_amb**

*DOI: http://dx.doi.org/10.5772/intechopen.96214*

**(ppm)**

**(ms/**

**n (°C)**

**(inch)**

**(L)**

**(ppm)**

**(ms/**

**n (°C)**

**(inch)**

**(L)**

**(°C)**

**(ppm)**

**(ms/**

**n (°C)**

**(inch)**

**(L)**

**(ppm)**

**(ms/**

**n (°C)**

**(inch)**

**(L)**

**(°C)**

**m)**

 14.6

 3.0 12.2

**m)**

**m)**

 22.1

 25.2

 2.0 2.5 10.2

> 24.2

 18.6

 3.5 14.2

 3.5 14.2

6.1 567.0 107.7 7.0 697.0 132.4 7.3 910.0 172.9

7.8 649.0 123.3

 5.3

 20.3

 25.0

 2.3

4.5 18.3 7.4 662.0 125.8

 9.1 7.3 792.0 150.5

 5.0 20.3 7.1 575.0 109.3

 2.5 10.2 6.6 546.0 103.7

 6.6

 20.0

 23.5

 2.5 10.2 3.0 12.2

 5.0 20.3

 2.8 11.2

 11.1

*The Canadian Integrated Northern Greenhouse: A Hybrid Solution for Food Security*

 8.1

 3.0 12.2

7.6 705.0 134.0

 15.0

0.0

 3.0 12.2 7.2 602.0 114.4

**m)**

2019-03-02 5.6 737.0 140.0 2019-03-05 4.2 783.0 148.8 4.3 674.0 128.1

2019-03-06 4.3 599.0 113.8

2019-03-11

2019-03-14

 5.1 923.0 175.4 5.0 770.0 146.3

2019-03-19

2019-03-25

**AVERAGE** 5.1 771.9 146.7

**Table A-4.**

*Monitoring*

 *of pH, EC, temperature*

 *and volume of nutrient solution for the Winter trial.*

 7.8 901.0 171.2

 26.0

 24.0

 3.6 14.5 4.9 444.8 84.5

 3.5 14.2 8.0 180.0 34.2

 25.2

 23.1

 2.8 11.3

 2.0

 8.1

8.0 500.0 95.0 7.4 713.0 123.2

 4.5 889.0 168.9

 24.3

 2.8 11.2 5.0 168.0 31.9

 25.8

 22.1

 4.5 18.3 4.8 269.0 51.1

 2.3

 9.1 4.9 348.0 66.1

 24.9

 23.4

 21.3

 2.5 10.2

 4.0 16.3

 2.0

 8.1

7.6 776.0 147.4 7.6 705.0 134.0 7.5 961.0 182.6 7.5 660.0 125.4

 24.2

 21.5

 24.8

 21.0

 19.5

 19.6

 4.0 16.3 7.3 602.7 114.5

 4.0 16.3 7.8 370.0 70.3

 6.0 24.4 7.5 363.0 69.0

 4.0 16.3 7.5 815.0 154.9

 5.3 21.3 7.5 522.0 99.2

 3.5 14.2 7.4 780.0 148.2

 23.9

 20.9

 24.0

 18.0

 22.0

 19.3

 3.5 14.1

 11.1

 5.0 20.3

 6.5 26.4

 2.0

 8.1

 3.0 12.2

 2.0

 8.1

 5.3 671.0 127.5

 21.4

 4.8 19.5 4.8 362.0 68.8

 23.7

 5.0 20.3 4.7 515.0 97.9

 22.7

 26.0

 2.8 11.2 2.5 805.0 153.0 3.5 14.2 4.3 680.0 129.2

 3.0 12.2 5.6 676.0 128.4

**Hoagland Nutrient Solution**

**CING**

**Vermicompost Nutrient Solution**

**Hoagland Nutrient Solution**

*Monitoring of pH, EC, temperature and volume of nutrient solution for the Fall trial.*


#### *The Canadian Integrated Northern Greenhouse: A Hybrid Solution for Food Security DOI: http://dx.doi.org/10.5772/intechopen.96214*

**Table A-4.**

*Monitoring of pH, EC, temperature and volume of nutrient solution for the Winter trial.*

**Vermicompost**

**68**

**DATE**

 **pH EC**

**T\_solutio**

**Level**

**Volume**

**pH EC**

**T\_solutio**

**Level**

**Volume**

**T\_amb**

**pH EC**

**T\_solutio**

**Level**

**Volume**

**pH EC**

**T\_solutio**

**Level**

**Volume**

**T\_amb**

**(ms/**

**n (°C)**

**(inch)**

**(L)**

**(ms/**

**n (°C)**

**(inch)**

4.0

 16.3

6.8 80.0

2.0

 8.1 6.5 130.0

**(L)**

**(°C)**

**(ms/**

**n (°C)**

**(inch)**

**(L)**

**(ms/**

**n (°C)**

**(inch)**

2.5

 10.2

**(L)**

**(°C)**

*Next-Generation Greenhouses for Food Security*

**m)**

**m)**

**m)**

**m)**

2018-12-01

2018-12-04

2018-12-04

2018-12-05

2018-12-10

2018-12-11

2018-12-13

 6.5 122.4 6.5 125.0

2018-12-17

2018-12-18

2018-12-21

**AVERAGE** 6.9 109.5

**Table A-3.**

*Monitoring*

 *of pH, EC, temperature*

 *and volume of nutrient solution for the Fall trial.*

 6.5 116.9

 23.2

 22.6

 3.2

 12.9 6.6 118.4

 3.0

 12.2 6.5 113.4

 6.9 95.0

 23.9

 4.0

 16.3 6.5 112.0

 6.6 93.9

 21.3

 4.0

 16.3 6.5 105.5

 19.2

 23.8

 22.8

 21.9

 3.4

 12.4

 20.3 6.9 68.2

 10.7

 4.0

 10.3 6.6 128.2

 2.5

 10.2

6.9 84.9

 13.8

 3.0

 12.2 6.3 165.3

 12.4

 10.2

 5.1

 18.7

 13.3

 4.0

 16.3

 15.0

 4.0

 16.3

 4.0

 16.3

 18.8 6.7 74.1

 13.3

 4.0

 16.3 6.2 151.6

0.0

 11.9

 5.0 4.0

 16.3

 20.3

 15.6

 7.5 117.0

 21.6

 2.5 3.0

3.0

 12.2 6.0 125.8

 12.2 6.3 93.5

 10.2 7.2 130.0

 7.0 107.0

 23.1

 3.0

 12.2 6.7 120.0

 7.0 117.0

 22.2

 3.0

 12.2 7.0 128.0

 22.9

 19.9

 21.9

 2.5 3.0

4.0

 16.3

6.6 71.8

 12.2

6.5 57.8

 11.1

 10.2

 20.2 7.7 73.0

 3.0

 12.2

6.9 67.0

 9.0

 7.0

 4.8

 19.3 7.0 137.0 0.0 6.1 105.3 0.0 6.0 136.4

 4.5

 18.3 6.9 134.0

 3.0

 12.2

7.0 58.0

 8.5

 5.0

 20.3 7.0 130.0

 7.2 110.0

 22.4

 3.0

 12.2

 8.1 105.0

 22.8

 3.0

 12.2 6.9 133.0

 22.7

 3.5

 14.2

0.0

 22.0 7.4 47.0

 11.9

 4.5

 18.3 7.1 63.0 0.0 6.6 129.0

 11.6

 11.7

 8.4

 9.1

 7.4

 8.8

 5.5

 22.4 0.0

 16.1

 6.0

 24.4

 8.9

 5.0

 20.3

 13.3

 6.0

 24.4

 10.0

 6.5

 26.4

 13.9

 6.0

 24.4

 13.9

 6.9 95.0

3.5

 14.2 6.6 123.0

 **Nutrient Solution**

**Hoagland Nutrient Solution**

**Vermicompost**

 **Nutrient Solution**

**Hoagland Nutrient Solution**

## **A.2 Temperature monitoring of the CING**

**Figure A.1.**

*Temperature monitoring outside and inside the CING, Spring trial, corresponding averages : 19.3°C and 21.2°C.*

**A.3 Humidity monitoring of the CING**

*DOI: http://dx.doi.org/10.5772/intechopen.96214*

*Temperature monitoring outside and inside the CING, Winter trial, corresponding averages: -2.4°C and*

*The Canadian Integrated Northern Greenhouse: A Hybrid Solution for Food Security*

*Humidity and temperature monitoring inside the CING, Spring trial, average relative humidity: 49.2 %.*

*Humidity and temperature monitoring inside the CING, Summer trial, average relative humidity: 59.1 %.*

**Figure A.4.**

**Figure A.5.**

**Figure A.6.**

**71**

*14.8°C.*

#### **Figure A.2.**

*Temperature monitoring outside and inside the CING, Summer trial, corresponding averages: 24.7°C and 25.4°C.*

#### **Figure A.3.**

*Temperature monitoring outside and inside the CING, Fall trial, corresponding averages: -3.4°C and 11.0°C.*

*The Canadian Integrated Northern Greenhouse: A Hybrid Solution for Food Security DOI: http://dx.doi.org/10.5772/intechopen.96214*

#### **Figure A.4.**

**A.2 Temperature monitoring of the CING**

*Next-Generation Greenhouses for Food Security*

*Temperature monitoring outside and inside the CING, Summer trial, corresponding averages: 24.7°C and*

*Temperature monitoring outside and inside the CING, Spring trial, corresponding averages : 19.3°C and*

*Temperature monitoring outside and inside the CING, Fall trial, corresponding averages: -3.4°C and 11.0°C.*

**Figure A.2.**

**Figure A.1.**

*21.2°C.*

**Figure A.3.**

**70**

*25.4°C.*

*Temperature monitoring outside and inside the CING, Winter trial, corresponding averages: -2.4°C and 14.8°C.*

## **A.3 Humidity monitoring of the CING**

**Figure A.5.** *Humidity and temperature monitoring inside the CING, Spring trial, average relative humidity: 49.2 %.*

**Experiment CING** Date 2018-06-19 Time 12:20 Weather Very sunny

**Experiment Greenhouse**

Average PAR 757

*DOI: http://dx.doi.org/10.5772/intechopen.96214*

Average PAR 473.25

**Experiment CING** Date 2018-06-19 Time 14:20 Weather Very sunny

Average PAR 545.5

**Table A-6.**

**Table A-7.**

**73**

*Light mapping, Summer trial.*

**Table A-5.**

*Light mapping, Summer trial.*

*Light mapping, Summer trial.*

PAR μmoles/m<sup>2</sup>

Left Row Right rows

PAR μmoles/m<sup>2</sup>

Left Row Right row

1 179 538 2 525 511 3 434 194 4 599 806 Average 434.25 512.25

 276.5 259.3 523.2 356.7 802.9 531.7 832.6 781.1 Average 608.8 482.2

Average 659.25 854.75

*The Canadian Integrated Northern Greenhouse: A Hybrid Solution for Food Security*

/s

/s

**Figure A.7.** *Humidity and temperature monitoring inside the CING, Winter trial, average relative humidity: 35.1 %.*

#### **Figure A.8.**

*Representation of the thermal resistance of the different layers of the CING window (Bergman, Lavine, Incropera, & Dewitt, 2011).*

## **A.4 Light mapping of systems**


*The Canadian Integrated Northern Greenhouse: A Hybrid Solution for Food Security DOI: http://dx.doi.org/10.5772/intechopen.96214*


#### **Table A-5.**

*Light mapping, Summer trial.*


#### **Table A-6.**

**A.4 Light mapping of systems**

*Next-Generation Greenhouses for Food Security*

**Experiment Greenhouse** Date 2018-06-19 Time 12:20 Weather Very sunny

*Humidity and temperature monitoring inside the CING, Winter trial, average relative humidity: 35.1 %.*

*Representation of the thermal resistance of the different layers of the CING window (Bergman, Lavine,*

Row Left Right 1 322 962 2 669 681 3 709 1077 4 937 699

PAR μmoles/m<sup>2</sup>

/s

**Figure A.7.**

**Figure A.8.**

**72**

*Incropera, & Dewitt, 2011).*

*Light mapping, Summer trial.*


**Table A-7.** *Light mapping, Summer trial.*

### *Next-Generation Greenhouses for Food Security*


**Experiment CING**

*DOI: http://dx.doi.org/10.5772/intechopen.96214*

Average PAR 37.58

*Light mapping, Fall trial, supplemental light in the CING.*

**Experiment CING** Date 2018-12-20 Time 15:00 Weather Very Sunny

Average PAR 296.14

**Experiment Greenhouse** Date 2019-03-19 Time 13:00 Weather Clear sky

Average PAR 569.61

*Light mapping, Greenhouse Winter trial.*

**Table A-10.**

**Table A-11.**

**Table A-12.**

**75**

*Light mapping, Fall trial.*

3 12.57 20.52 4 20 18.94 Average 34.47 40.69

*The Canadian Integrated Northern Greenhouse: A Hybrid Solution for Food Security*

Row Left Right 1 53.5 278 2 145.08 509 3 166.34 506.4 4 187.46 523.3 Average 138.10 454.18

Row Left Right 348.10 685.70 598.00 536.90 498.50 580.60 638.90 670.20 Average 520.88 618.35

PAR μmoles/m2/s

PAR μmoles/m2/s

#### **Table A-8.**

*Light mapping, Fall trial, only supplemental light in the greenhouse.*


#### **Table A-9.**

*Light mapping, Fall trial only.*


*The Canadian Integrated Northern Greenhouse: A Hybrid Solution for Food Security DOI: http://dx.doi.org/10.5772/intechopen.96214*


**Table A-10.**

**Experiment Greenhouse** Date 2018-12-20 Time 19:00 Weather Night

*Next-Generation Greenhouses for Food Security*

Average PAR 56.69

*Light mapping, Fall trial, only supplemental light in the greenhouse.*

**Experiment Greenhouse** Date 2018-12-20 Time 14:30 Weather Very sunny

Average PAR 88.22

**Experiment CING** Date 2018-12-20 Time 19:00 Weather Night

**Table A-8.**

**Table A-9.**

**74**

*Light mapping, Fall trial only.*

Row Left Right 51.6 29.14 43.68 43.65 65.87 51.87 86.31 81.37 Average 61.87 51.51

Row Left Right 76.14 76.2 66.27 73.3 88.2 98.53 114.92 112.23 Average 86.38 90.07

Row Left Right 1 48.09 63.52 2 57.23 59.76

PAR μmoles/m2/s

PAR μmoles/m2/s

PAR μmoles/m2/s

*Light mapping, Fall trial, supplemental light in the CING.*


## **Table A-11.**

*Light mapping, Fall trial.*


#### **Table A-12.**

*Light mapping, Greenhouse Winter trial.*


**Table A-13.**

*Light mapping, CINGWinter trial.*

## **A.5 Thermal curtain heat transfer rate calculation**

Heat transfer rate calculation

$$q\_{\rm x} = \frac{T\_{\rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \rm \$$

**Author details**

**77**

**Table A-15.**

**Table A-14.**

*Heat transfer rate calculation result.*

*Parameters for heat transfer rate calculations.*

David Leroux\* and Mark Lefsrud

provided the original work is properly cited.

McGill University, Sainte-Anne-de-Bellevue, Canada

\*Address all correspondence to: david.leroux3@mail.mcgill.ca

© 2021 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

Heat transfer rate, qx (Watts) without curtain and stagnant air layer 282.4 Heat transfer rate, qx (Watts) with curtain and stagnant air layer 17.2

) 7.27

**Parameters Value**

*The Canadian Integrated Northern Greenhouse: A Hybrid Solution for Food Security*

Thickness of Curtain, LA (m) 0.001 Thickness of air Layer, LB (m) 0.15 Thickness of Twin Wall polyecarbonate sheet, LC (m) 0.008

Temperature gradient, T∞,1 -T∞,A (K) 15.0

Thermal conductivity of thermal curtain, kA (W/m.K) 0.104 (AZOMaterials, 2020) and (Ludvig

Thermal conductivity of air layer, kB (W/m.K) 25.3x10<sup>3</sup> (Bergman, Lavine, Incropera, &

20 (EngineeringToolBox, 2020)

30 (EngineeringToolBox, 2020)

Svensson, 2020)

Dewitt, 2011)

37.86 (PALRAM, 2010)

Convective heat transfer coefficient of air inside CING,

Convective heat transfer coefficient of air outside

*DOI: http://dx.doi.org/10.5772/intechopen.96214*

Thermal conductivity of Twin-Wall polycarbonate

h1 (W/(m<sup>2</sup> .K)

CING h4 (W/ m<sup>2</sup> .K)

Sheet, kC (W/m.K)

Area of Window (m<sup>2</sup>

**Figure A.9.** *Humidity and temperature monitoring inside the CING, Fall trial, average relative humidity: 42.2 %.*

*The Canadian Integrated Northern Greenhouse: A Hybrid Solution for Food Security DOI: http://dx.doi.org/10.5772/intechopen.96214*


#### **Table A-14.**

**A.5 Thermal curtain heat transfer rate calculation**

Average PAR 248.61

**Experiment CING** Date 2019-03-19 Time 13:30 Weather Clear sky

*Next-Generation Greenhouses for Food Security*

*qx* <sup>¼</sup> *<sup>T</sup>*∞,1 � *<sup>T</sup>*∞,4

½ � ð Þþ 1*=h*1*A* ð Þþ *LA=kAA* ð Þþ *LB=kBA* ð Þþ *LC=kCA* ð Þ 1*=h*4*A*

*Humidity and temperature monitoring inside the CING, Fall trial, average relative humidity: 42.2 %.*

Row Left Right 110.96 174.20 261.50 257.80 59.44 197.55 475.30 452.10 Average 226.80 270.41

PAR μmoles/m2/s

Heat transfer rate calculation

*Light mapping, CINGWinter trial.*

**Table A-13.**

**Figure A.9.**

**76**

*Parameters for heat transfer rate calculations.*


#### **Table A-15.**

*Heat transfer rate calculation result.*

## **Author details**

David Leroux\* and Mark Lefsrud McGill University, Sainte-Anne-de-Bellevue, Canada

\*Address all correspondence to: david.leroux3@mail.mcgill.ca

© 2021 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

## **References**

[1] Ramin Shamshiri, R., Kalantari, F., C. Ting, K., R. Thorp, K., A. Hameed, I., Weltzien, C., . . . Mojgan Shad, Z. (2018). Advances in greenhouse automation and controlled environment agriculture: A transition to plant factories and urban agriculture. International Journal of Agricultural and Biological Engineering, 11(1), 1–22.

[2] Touliatos, D., Dodd, I. C., & McAinsh, M. (2016). Vertical farming increases lettuce yield per unit area compared to conventional horizontal hydroponics. Food Energy Secur, 5(3), 184–191.

[3] Agrilyst. (2017). State of Indoor Farming.

[4] Benis, K., Reinhart, K., & Ferrão, P. (2017). Building-Integrated Agriculture (BIA) In Urban Contexts: Testing A Simulation-Based Decision Support Workflow. Paper presented at the International Building Performance Simulation Association, San Francisco.

[5] MIT. (2016). Leafy Green Machine Business Feasability Evaluation. Retrieved from Laboratory for Sustainable Business:

[6] Liu, X. (2014). Design of a Modified Shipping Container as Modular Unit for the Minimally Structured & Modular. (Master of Science). University of Arizona.

[7] Gaudet, P. (2017). Food Security in Northern Canada (FOOD SINC) Unit: Weather Data and Environment Control Analysis for the Determination of Automation System Parameters. Faculty of Agricultural and Environmental Sciences, McGill University.

[8] Fernandez, D. (Producer). (2009, February 2 ). The Hoaglands Solution for Hydroponic Cultivation. Science in Hydroponics.

[9] Lennard, W. A., & Leonard, B. V. (2006). A comparison of three different hydroponic sub-systems (gravel bed, floating and nutrient film technique) in an Aquaponic test system. Aquacult Int, 539–550.

[10] Brechner, M., & Both, A. J. (2013). Hydroponic Lettuce Handbook. Cornell University.

[11] Ludvig Svensson. (2020). TEMPA7567DFB CS Product Sheet.

[12] Beshada, E., Zhang, Q., & Boris, R. (2006). Winter performance of a solar energy greenhouse in southern Manitoba. Canadian Biosytems Engineering, 49, 5.1–5.8.

**79**

**1. Introduction**

**Chapter 4**

Conditions

*Erick K. Ronoh*

**Abstract**

Radiation Exchange at Greenhouse

Greenhouses generally exhibit a greater degree of thermal radiation interaction

with the surroundings than other buildings. A number of greenhouse thermal environment analyses have handled the thermal radiation exchange in different ways. Thermal radiation exchange at greenhouse surfaces is of great interest for energy balance. It dominates the heat transfer mechanisms especially between the cover material surface and the surrounding atmosphere. At these surfaces, the usual factors of interest are local temperatures and energy fluxes. The greenhouse surfaces are inclined and oriented in various ways and thus can influence the radiation exchange. The scope of this work is determination of the thermal radiation exchange models as well as effects of surface inclination and orientation on the radiation exchange between greenhouse surfaces and sky. Apart from the surface design and the thermal properties of the cover, the key meteorological parameters influencing longwave and shortwave radiation models were considered in detail. For the purpose of evaluating surface inclination and orientation effects, four identical thermal boxes were developed to simulate the roof and wall greenhouse surfaces. The surface temperatures and atmospheric parameters were noted under all-sky conditions (clear-sky and overcast). Differences in terms of surface-to-air temperature differences at the exposed roof and wall surfaces as influenced by surface inclination and orientation are discussed in this work. Overall, the findings of this work form a basis for decisions on greenhouse design improvements and

climate control interventions in the horticultural industry.

**Keywords:** Radiation exchange, Greenhouses, Tilted surfaces, Roof, Wall, Sky

Thermal radiation dominates the heat transfer mechanisms especially between the cover material surface and the surrounding atmosphere. The radiation heat transfer depends on the orientation of the surfaces relative to each other as well as their radiation properties and temperatures [1]. For a non-horizontal surface (e.g. roof and wall), the radiation exchange between the surface and the sky is weighted by a view factor. The view factor gives the fraction of the view from a base surface obstructed by a given other surface [2]. Generally, single-span greenhouses are oriented such that the length runs east–west. This orientation maximizes winter sunlight and heat gain in the greenhouse [3]. Gutter-connected greenhouses are

Tilted Surfaces under All-Sky

## **Chapter 4**

**References**

184–191.

Farming.

[1] Ramin Shamshiri, R., Kalantari, F., C. Ting, K., R. Thorp, K., A. Hameed, I., Weltzien, C., . . . Mojgan Shad, Z. (2018). Advances in greenhouse

*Next-Generation Greenhouses for Food Security*

[9] Lennard, W. A., & Leonard, B. V. (2006). A comparison of three different hydroponic sub-systems (gravel bed, floating and nutrient film technique) in an Aquaponic test system. Aquacult Int,

[10] Brechner, M., & Both, A. J. (2013). Hydroponic Lettuce Handbook. Cornell

[12] Beshada, E., Zhang, Q., & Boris, R. (2006). Winter performance of a solar

[11] Ludvig Svensson. (2020). TEMPA7567DFB CS Product Sheet.

energy greenhouse in southern Manitoba. Canadian Biosytems Engineering, 49, 5.1–5.8.

539–550.

University.

automation and controlled environment

International Journal of Agricultural and Biological Engineering, 11(1), 1–22.

agriculture: A transition to plant factories and urban agriculture.

[2] Touliatos, D., Dodd, I. C., & McAinsh, M. (2016). Vertical farming increases lettuce yield per unit area compared to conventional horizontal hydroponics. Food Energy Secur, 5(3),

[3] Agrilyst. (2017). State of Indoor

[4] Benis, K., Reinhart, K., & Ferrão, P. (2017). Building-Integrated Agriculture (BIA) In Urban Contexts: Testing A Simulation-Based Decision Support Workflow. Paper presented at the International Building Performance Simulation Association, San Francisco.

[5] MIT. (2016). Leafy Green Machine Business Feasability Evaluation. Retrieved from Laboratory for

[6] Liu, X. (2014). Design of a Modified Shipping Container as Modular Unit for the Minimally Structured & Modular. (Master of Science). University of

[7] Gaudet, P. (2017). Food Security in Northern Canada (FOOD SINC) Unit: Weather Data and Environment Control Analysis for the Determination of Automation System Parameters. Faculty of Agricultural and Environmental Sciences, McGill University.

[8] Fernandez, D. (Producer). (2009, February 2 ). The Hoaglands Solution for Hydroponic Cultivation. Science in

Sustainable Business:

Arizona.

Hydroponics.

**78**
