SUN PAPA Solar Greenhouse

SUN PAPA was a team project designed for the ENME 519.01 Innovation and Entrepreneurship in Renewable Energy course during the Shantou group study program.

“The world needs to produce at least 50% more food to feed 9 billion people by 2050. But climate change could cut crop yields by more than 25%.” (World Bank, 2016)

Food security is becoming a major issue, especially in China, where the population exceeds 1.4 billion and crop yields are reduced due to pollution and land redevelopment. SUN PAPA is a solar-powered smart greenhouse that automatically maintains optimal conditions for crop growth.

FEATURES

     • Completely solar powered

     • Automatically controls interior temperature, lighting, air quality, and humidity

     • Modular structure, easily scalable

     • Adaptable for different environments and crops

     • Efficient use of materials, reliable electronics

TEAM

Our team consisted of six students from the University of Calgary and Shantou University. Our company was called Suntury.

Zeyu – Chief Executive Officer – Engineering and design of mechanical and electrical components.

Gavin – Chief Operating Officer – Day-to-day operations of Suntury. Assist in implementation of components. 

Susan – Chief Financial Officer – Finances, market analysis, price estimations.

Elsa – Chief Production Officer – Assembling the product, programming of microcontrollers.

Ming – Project Manager – Assembling the product, price estimations and projections.

Dora – Chief Design Officer – Design of logos, design fair poster, and brochure. Marketing. 

REQUIREMENTS

We had a total of one month to complete our design. This included preliminary analysis, documentation, working prototype, and marketing material. The time for building the prototype was restricted to one week and the budget for materials was 750RMB (CAD150).

The completed project included eight parts:

1. Reverse engineering of existing products

2. Preliminary designs

3. Patent search

4. Bill of materials and cost estimate

5. CAD drawings and circuit schematic

6. Breakeven analysis

7. Business plan

8. Poster and brochures

We started by researching existing solar technologies and learning DFA/DFM techniques. After a lot of brainstorming, we designed the mechanical structure and electrical control system, taking part selection, placement, and coherence into careful consideration.

Exterior

Streamlined, Modular, Rigid.

Our design features a streamlined shape which is both aesthetically pleasing and functional. The base and side frames are made of aluminum profiles as it’s light, rigid, and corrosion resistant. It gives strength to the structure and provides mounting points for the solar panels and motors. The top is a matrix of PVC piping, which doubles as water lines that integrate the watering system into the structure. The combination of aluminum and PVC ensures rigidity while reducing manufacturing costs. It also allows the greenhouse to
easily scale to the customer’s requirements.  

The curved shape allows water to flow down into a collection bin at the bottom where it could be pumped to the plants for watering or cooling. The frame is modular, with the ability to have multiple units placed side by side or end to end. The control system is placed in a central location to make connecting additional units easy.

Interior

Flexible, Safe.

Inside, the electrical control system is in a weather sealed box placed at the rear, the tallest point of the greenhouse. This effectively shields the control system from the external environment while making it easy for maintenance and repair.

Depending on the crop type, shelving can be installed to grow multiple layers of crops. Connection points on the sides of the greenhouse allow multiple layers of water lines and lighting fixtures to be installed.

Full automatic control of lighting, heating, watering, and air quality.

Lighting

Lighting is provided using RGB and white LEDs which turn on automatically in low light. They can also be configured to light up at certain hours of the day or with certain colors, depending on the crop requirements. Installed at the top of the greenhouse and can be installed with shelving.

Heating

The greenhouse is heated using forced-air fin heaters that turn on automatically when the interior temperature drops below a threshold.

Watering

An exterior water storage tank collects rain water, which is pumped to the water system. Water lines are integrated into the top of the greenhouse and automatically water the plants based on soil interior humidity.

Air Quality

Air quality is maintained by monitoring the interior carbon dioxide and oxygen content. Depending on the crop requirements, ventilation or CO₂/O₂ generators will be engaged.

Solar Panels

Each solar panel is mounted on its own stepper motor and equipped with a light sensor. The control system uses the exterior lighting, interior lighting, and interior temperature to determine the optimum position of the solar panels. For example, if the interior is getting too much solar radiation and becomes too hot, the solar panels will tilt to cover the greenhouse more and produce more electricity.

Controller/Battery

Dual controllers and dual batteries are housed in a weather sealed casing for redundant and reliable operation. The control system is modular which allows more complex environment control. It is placed at the back of the greenhouse to make maintenance and repair simple.

Our prototype greenhouse was 2m x 1m x 1m powered by three 20W solar panels and two 12V 8AH batteries. Two Arduino microcontrollers and multiple sensors were used to control the interior systems. A full list of the components, quantities, and prices can be found here. Together, our prototype costs around 680RMB, within our budget of 750RMB. With our design and component selection, the greenhouse should be able to maintain the interior environment for 12 hours with no sunlight. Unfortunately, due to time constraints, we were not able to test our design. Overall, this was a great opportunity for us to learn about renewable energy and how we can build sustainability into our work and life.