Design Scheme of Energy-Saving and Heat-Preserving Multi-Span Greenhouse

In recent years, multi-span greenhouses have been widely promoted in flower cultivation, vegetable growing, and fruit & vegetable cultivation fields. Leveraging core advantages such as high land utilization rate, convenient mechanical control, and flexible internal space usage, they have become a key facility for large-scale modern agricultural production.

However, in winter low-temperature areas, traditional multi-span greenhouses often rely on heating equipment to achieve over-winter production—this not only increases energy consumption costs but also directly impacts planting profitability.

To address this challenge, we have launched a professional heat-preserving multi-span greenhouse design scheme. Under normal sunny conditions, even when the external temperature drops to -15℃, the minimum temperature inside the greenhouse can be stably maintained above 3℃ at night without additional heating, perfectly solving the heat preservation problem for over-winter planting in low-temperature regions.

Core Design Key Points

The scheme focuses on three core dimensions to ensure optimal heat preservation performance, as detailed below:

1. Multi-Layer Film Covering Design: Building a Closed Heat-Insulation Barrier

By optimizing the multi-span greenhouse’s framework structure, the covering materials for the top and surrounding areas are upgraded to 2-layer or 3-layer films. The gaps between films form multiple independent closed heat-insulation layers, effectively blocking heat loss from the greenhouse and improving overall heat preservation performance.

Critical Note: The distance between heat-insulation layers must be controlled above 50cm to maximize the air insulation effect and ensure the heat preservation performance meets standards.

Film covering schemes can be flexibly adjusted based on crop characteristics:

For flowers requiring high winter temperatures and low light: Adopt a fully closed multi-layer film structure to reduce heat loss and stabilize the greenhouse’s internal temperature.
For light-loving vegetables, fruit trees, and some flowers: Install openable vents in the film-covered areas (top and surroundings). During the day, use natural ventilation to adjust the greenhouse’s internal temperature (avoiding high-temperature damage to crops) while ensuring sufficient light to meet crop photosynthesis needs.

2. Top + Surrounding Heat Preservation Cover System: Enhancing Night Heat Preservation Capacity

In the horizontal area on the top of the multi-span greenhouse, a mechanical transmission structure of "gear rack + steel wire film rolling" is adopted, with an automatically retractable heat preservation cover installed:

Nighttime: Unfold the heat preservation cover to form a heat-preservation protective layer on the greenhouse top, reducing heat radiation loss.
Daytime: Retract the heat preservation cover to avoid blocking natural light from entering the greenhouse.

Selection of heat preservation covers should be based on local low-temperature conditions and budget. Current mainstream products include:

Type of Heat Preservation Cover	Specifications & Features	Applicable Scenarios
Ordinary Space Cotton Cover	Weight options: 120g, 150g, 200g, 260g; high cost-effectiveness	Areas with non-extreme low temperatures
New Multi-Layer Folded Cover	5-layer structure (2 layers PE cloth + 1 layer film + 2 layers cotton); 7-layer structure (2 layers PE cloth + 2 layers film + 3 layers cotton); higher heat preservation coefficient, stronger aging resistance and snow-wind resistance	Severe cold areas with temperatures ≤ -15℃

3. Reconstruction of North Wall with Heat-Preserving Composite Board: Resisting Cold North Wind Invasion

In northern regions, winter is dominated by northwest winds (strong wind + low temperature), which is one of the main directions of greenhouse heat loss. To solve this problem:

Reconstruct the north wall of the multi-span greenhouse into a 15cm-thick heat-preserving composite board. This design has two key advantages:

Does not affect greenhouse lighting (no direct sunlight on the north side).
Greatly improves the north wall’s heat insulation performance, effectively preventing outdoor cold wind and low temperatures from infiltrating, and further consolidating the stability of the greenhouse’s internal temperature.

Scheme Advantages & Value

Through the synergy of the three designs above, the multi-span greenhouse can maintain a temperature suitable for crop growth in severe cold seasons without additional heating. This not only reduces energy consumption costs but also improves planting benefits, providing a reliable solution for large-scale and efficient modern agricultural production in low-temperature areas.