Semi-High Tech Greenhouse Design and Estimation Top Vent Polyhouse

A semi-high-tech greenhouse is a type of greenhouse that combines the best features of traditional and modern greenhouse technologies. It is a cost-effective solution for small-scale farmers who want to increase their yield and profits without investing too much in advanced equipment and technology. However, a semi-high-tech greenhouse can still provide excellent results despite its simplicity. It can help to extend the growing season, protect crops from pests and disease, and increase the yield and quality of crops. This is achieved through the use of different materials, such as glass or polyethylene, and by adjusting the ventilation, irrigation, and heating systems.

In terms of cost, a semi-high-tech greenhouse is much cheaper than a fully automated high-tech greenhouse. It requires less energy, fewer materials, and lower maintenance costs. This makes it an attractive option for small-scale farmers who want to increase their yield and profitability without incurring too much expense.

Top Vent Semi High Tech Greenhouse

A top vent is a common feature in semi-high-tech greenhouses that provides an efficient way to regulate temperature, humidity, and airflow inside the structure. It is a simple and effective way to control the environment in the greenhouse without the need for expensive and complex equipment.

The top vent is located at the highest point of the greenhouse roof and is designed to open and close automatically (or manually) based on the temperature and humidity levels inside the structure. When the temperature inside the greenhouse rises above a certain level, the vent opens to release hot air and allow fresh air to enter. This helps maintain a comfortable temperature and prevent overheating, damaging crops, and reducing yield.

Similarly, Simple GI or Black Piped Green house mentioned in this site in Greenhouse Topic can be made semi-high Tech or High Tech by the use of auxiliary equipment and facilities.

Design and Drawings

Figure 1: Semi-High Tech Top Vent Greenhouse Front Elevation

Figure 2: Truss Details for Semi-High Tech Top Vent Greenhouse

Figure 3: Footing Plan for Semi-High Tech Top Vent Greenhouse

Figure 4:Double (Attached) Semi High Tech Top Vent Greenhouse.

The facilities that may be required for Semi-High Tech Greenhouse are:

• Heating system: Semi-high-tech greenhouses require a heating system to maintain a consistent temperature during cold weather conditions. A heating system can consist of various options such as a boiler or a furnace that heats water or air that is circulated throughout the greenhouse. The heating system can be controlled using a thermostat, which ensures that the temperature remains within the desired range.
• Cooling system: In the summer, the temperature inside the greenhouse can become too high, causing damage to crops. A cooling system such as an evaporative cooling pad or a fan can help to regulate the temperature and keep it within the desired range. The cooling system can also be connected to a temperature and humidity sensor that automatically adjusts the system to maintain the desired conditions. Semi-High tech may be with or without sensors.
• Ventilation system: Proper ventilation is critical in a semi-high-tech greenhouse as it helps to regulate temperature and humidity, reduce the risk of disease, and promote healthy plant growth. A ventilation system consists of fans or louvers that can be opened or closed to control the flow of air inside the greenhouse.
• Irrigation system: A semi-high-tech greenhouse requires an irrigation system to provide water to the plants. A drip irrigation system is a popular option as it delivers water directly to the plant's roots, reducing water waste and preventing soil erosion.
• Lighting system: In areas with low sunlight, a lighting system may be necessary to provide adequate light to the plants. LED grow lights are an energy-efficient option that can be customized to provide the optimal light spectrum for different types of plants.
• Environmental control system: An environmental control system is an essential component of a semi-high-tech greenhouse. It consists of sensors, controllers, and software that monitor and adjust the temperature, humidity, CO2 levels, and other environmental factors to create an optimal growing environment for the plants.

Overall, semi-high-tech greenhouses provide a cost-effective way to grow crops in a controlled environment. By incorporating the right facilities, a semi-high-tech greenhouse can provide a stable environment that promotes healthy plant growth and maximizes yield.

Specifications

• To ensure the durability of the greenhouse structure and its ability to withstand harsh weather conditions, it is recommended that 90 GSM or more than 90 GSM Silpaulin Plastic/200 micron UV Plastic be used for plastic/insect net and mulching. The diameter of the pole or post used should be 2 inches, whether made of GI Pipe or Black Iron Pipe. In the truss or lateral section, the diameter or length of the pipe used should be 1 inch, in the case of square pipes.
• The middle pole should be 4 meters high, while the side pole should be 3 meters high, but these measurements may vary slightly depending on the geographical region. The distance between poles should be 3 meters, and the width of the structure should be between 7 to 10 meters. The length can be adjusted based on the available space.
• For the truss section, round pipes are recommended over square pipes, as they can distribute weight and stress more evenly and are better suited to withstand greater pressure and bending moments. Round pipes also tend to be more resistant to buckling and deformation under pressure, making them a more suitable choice for the truss section of a greenhouse. In addition, round pipes are preferred for ergonomic reasons during roofing work.
• Two methods can be used to secure the plastic cover onto the greenhouse frame: profile locking and zigzag locking. In profile locking, a metal or plastic profile is attached to the frame using screws or bolts, and the plastic cover is then clamped onto the profile using special locking strips. For GI or black-piped greenhouses, it is recommended to use a galvanized iron or stainless steel profile to prevent rusting and corrosion.
• In zigzag locking, a zigzag wire is used to hold the plastic cover onto the greenhouse frame. The wire is passed through the plastic cover and then looped around the greenhouse frame at regular intervals to create a secure hold. For GI or black-piped greenhouses, a wire made of galvanized iron is recommended to prevent rusting and corrosion.
• In a semi-high-tech greenhouse, a drip irrigation system is typically used. This system consists of a network of tubes that are placed on the ground or buried underground. The tubes have small holes or emitters that allow water to slowly drip onto the plants' roots. This system is highly efficient as it delivers water directly to the roots, minimizing wastage. A timer or controller can be installed to enhance the irrigation system's efficiency. This device allows the grower to automate the irrigation process and set a specific schedule for watering the plants. Additionally, a nutrient delivery system can also be incorporated into the irrigation system to provide the plants with essential nutrients.
• The thermal net is installed over the greenhouse roof and is held in place by specially designed clips or hooks. It is typically installed during the fall or winter season when temperatures begin to drop, and it is removed in the spring when the weather begins to warm up. The primary function of the thermal net is to reduce heat loss from the greenhouse by trapping a layer of insulating air between the thermal net and the greenhouse cover. This layer of air acts as a buffer against the cold outside air, reducing the amount of energy needed to heat the greenhouse and improving overall energy efficiency.

For Estimate, various samples of the descriptions of works may be used.

Sample

Designing a semi-high-tech greenhouse in Nepal requires careful consideration of various factors such as location, climate, availability of resources, and the specific crops to be grown. Here are some key design elements to consider:

• Location: The greenhouse should be located in an area that receives plenty of sunlight and is protected from strong winds. The site should also be easily accessible for transporting materials and products.
• Size and Orientation: The size of the greenhouse should be based on the number of crops to be grown and the available space. The orientation of the greenhouse should be such that it receives maximum sunlight throughout the day.
• Frame: The frame of the greenhouse can be made of GI pipe or black iron pipe. The poles used in the truss section should be round pipes as they can withstand greater pressure and bending moments than square pipes. The width limit for the structure should be between 7 to 10 meters.
• Covering: The greenhouse should be covered with 90 GSM or more than 90 GSM Silpaulin Plastic/200 micron UV Plastic. UV-stabilized anti-insect nets should also be used for side covering. The plastic cover should be secured onto the greenhouse frame using zigzag wire or metal or plastic profiles.
• Ventilation: Proper ventilation is essential for the growth of plants in a greenhouse. Top vent systems can be installed in the greenhouse to regulate the temperature and humidity levels.
• Cooling: Cooling systems such as evaporative cooling pads or fans can be installed to maintain a cool and comfortable environment for the plants.
• Irrigation: A drip irrigation system can be installed to ensure efficient water usage and prevent waterlogging.
• Lighting: Artificial lighting can be installed to provide additional light for plants during the winter months or in areas with low sunlight.
• Automation: Automating greenhouse operations can save time and resources. Systems for monitoring temperature, humidity, and other factors can be installed for efficient management of the greenhouse.

Designing a semi-high-tech greenhouse in Nepal requires a balance between cost, efficiency, and sustainability. By considering these key elements, it is possible to create a greenhouse that can maximize crop yield and provide a sustainable income source for Nepal farmers.