Freshwater is the Middle East’s most precious resource. In many Gulf countries, groundwater is being

depleted faster than it can recharge, and desalinated water is expensive. Greenhouse cooling systems

— particularly evaporative cooling — consume significant quantities of water, sometimes more than

irrigation itself. A well-designed desert greenhouse must balance the need for cooling with the

imperative to minimize water use.

Cooling System Design: The Heart of a Desert Greenhouse

Wet Wall (Evaporative Cooling Pad) and Fan Systems

The most widely used and cost-effective cooling method for greenhouses in the Middle East is the pad

and-fan (or wet wall) evaporative cooling system. Here is how it works:

1. Exhaust fans mounted on one wall pull hot air out of the greenhouse, creating negative pressure.

2. Cooling pads (typically made of corrugated cellulose) on the opposite wall are kept saturated by a

recirculating water system.

3. Hot outside air is drawn through the wet pads, where water evaporation absorbs heat and cools the air.

4. Cooled air flows through the greenhouse, lowering the interior temperature by 8–15°C depending on

ambient humidity.

In hot, dry conditions — typical of inland Saudi Arabia and the UAE — evaporative cooling is highly

effective because the dry air has a large capacity to absorb moisture. In coastal areas where humidity is

higher, the cooling efficiency drops, and supplemental strategies may be needed.

Design tip: The cooling pad area must be correctly sized to the greenhouse volume and local climate

data. Undersized pads result in inadequate cooling; oversized pads waste water and energy. A

reputable manufacturer will calculate the required pad area and fan capacity based on your specific

location.

External Shading Systems

An external retractable shading screen is essential in desert greenhouse design. By blocking a portion

of solar radiation before it reaches the covering material, external shading can reduce the cooling load

by 20–40%. Modern systems use aluminized shade cloth that reflects infrared radiation while allowing

enough photosynthetically active radiation (PAR) to pass through for plant growth.

Key design considerations:

• Shade percentage: Typically 40–65% for vegetable production; higher for ornamentals or low-light

crops.

• Retractable operation: The screen should be able to open fully during cooler months or early morning to

maximize light when it is needed.

• Wind resistance: The screen mechanism must withstand the wind loads associated with desert storms.

Natural and Forced Ventilation

Even with evaporative cooling, ventilation design matters. Ridge vents (roof vents) allow hot air —

which naturally rises — to escape, while side vents or roll-up curtains allow cooler air to enter. In a well

designed greenhouse Middle East project, ventilation works in concert with the cooling system:

• During mild weather (winter, early mornings), natural ventilation alone may suffice.

• During peak summer, the wet wall and fan system takes over, and vents are closed to maintain negative

pressure.

Misting and Fogging Systems

High-pressure fogging systems can further reduce greenhouse temperatures by 3–5°C beyond what

pad-and-fan cooling achieves alone. Fine water droplets (10–50 microns) evaporate almost instantly,

absorbing heat without wetting plant surfaces. These systems are particularly useful in the transition

seasons when humidity is moderate but temperatures are still high.

Covering Material Selection for Desert Environments

The choice of covering material has a profound impact on greenhouse performance in the Middle East.

The two most common options are polycarbonate sheets and glass, each with distinct advantages and

trade-offs in desert conditions.

Polycarbonate (PC) Sheet Greenhouses

Polycarbonate multi-wall panels — typically 8mm to 16mm twin-wall or multi-wall — are widely used in

desert greenhouse projects for several reasons:

• Impact resistance: PC panels are 200 times more impact-resistant than glass, making them highly

resistant to hail and wind-borne debris during sandstorms.

3/7• Thermal insulation: The multi-wall air-channel structure provides an R-value of 1.6–2.5 (depending on

thickness), roughly double that of single-pane glass. This reduces heat gain during the day and slows

heat loss on cold desert nights.

• Light diffusion: PC panels scatter incoming light, distributing it evenly across the crop canopy and

reducing hot spots that can scorch leaves under intense desert sun.

• UV protection: Quality PC panels come with co-extruded UV-protective layers that prevent yellowing and

degradation — critical in a region with extreme UV exposure.

• Weight: At roughly 1.5 kg/m² for 8mm twin-wall (compared to 10–12 kg/m² for glass), PC panels reduce

structural load requirements and simplify installation.

Trade-offs: PC panels have a service life of 10–15 years before UV degradation necessitates

replacement. Light transmission (76–82%) is lower than glass (89–91%), though the diffused light

quality is often preferable for plant growth.

Glass Greenhouses

Tempered glass (usually 4–5mm) is used in high-end commercial greenhouses and research facilities:

• Maximum light transmission: Glass allows 89–91% of visible light to pass through — the highest of any

rigid covering material. This is advantageous in winter when light levels drop.

• Longevity: Glass does not yellow or degrade under UV exposure. With proper maintenance, glass panels

can last 25+ years with unchanged optical properties.

• Aesthetics and visibility: Glass provides a clear, transparent view — valuable for display greenhouses,

research facilities, or agritourism projects.

Trade-offs: Glass is heavy, requiring stronger (and more expensive) structural framing. It is brittle and

vulnerable to hail and impact. In extreme heat, the high light transmission can work against you,

requiring more aggressive shading and cooling. Single-pane glass offers poor insulation (R-value ~0.9),

leading to greater nighttime heat loss on cold desert nights where temperatures can drop sharply.

Recommendation for Desert Climates

For most commercial greenhouse projects in Saudi Arabia, the UAE, and other Gulf countries,

polycarbonate sheet greenhouses or film-covered multi-span greenhouses offer the best balance of

cost, durability, insulation, and ease of maintenance. Glass is justified when maximum light transmission

or long-term aesthetics are the priority, and the budget can accommodate the heavier structure and

additional cooling requirements.

Internal link suggestion: Explore our arched greenhouse solutions, which are well-suited for Middle

East climates and were used in our Abu Dhabi project.

4/7Water Resource Management in Desert Greenhouses

Drip Irrigation and Precision Water Delivery

Drip irrigation is the standard for greenhouse crop production in water-scarce regions. By delivering

water directly to the root zone through emitters, drip systems achieve 85–95% water-use efficiency —

far higher than flood or sprinkler irrigation. In a desert greenhouse, drip irrigation should be integrated

with:

• Fertigation systems that deliver precise nutrient solutions through the same drip lines

• Soil moisture sensors that trigger irrigation based on actual plant needs rather than a fixed schedule

• Pressure-compensating emitters that ensure uniform water distribution across the entire greenhouse,

regardless of elevation differences

Condensate Recovery

In a pad-and-fan cooled greenhouse, the air handling process involves significant evaporation. Some of

this moisture can be recovered through condensation on heat exchanger surfaces or specialized

dehumidification equipment. While not a complete solution, condensate recovery can offset 10–20% of

cooling water consumption in well-designed systems.

Seawater Greenhouse Concepts

In coastal desert regions, innovative seawater greenhouse designs use saltwater for evaporative

cooling, eliminating the need for freshwater in the cooling process. The seawater evaporates in the

cooling pads, and the humid air is then condensed to produce freshwater for irrigation. While these

systems are still relatively niche and capital-intensive, they represent a promising direction for coastal

desert agriculture in the Gulf.

Structural Design Considerations for Desert Greenhouses

Wind and Sand Resistance

Desert greenhouses must withstand sustained winds of 100–120 km/h during shamal events. Key

structural design elements include:

• Hot-dip galvanized steel frame with a minimum zinc coating of Z275 (275 g/m²) for corrosion resistance

5/7• Aerodynamic roof profiles (arched or gothic) that reduce wind uplift forces

• Reinforced connections at all structural joints

• Sealed gable ends to prevent wind-driven sand infiltration

UV and Thermal Degradation Protection

All non-metallic components — covering materials, film, shade cloth, drip tape, and electrical insulation

— must be UV-stabilized for the extreme radiation levels in the Middle East. Specify materials with

documented UV warranties of at least 5 years (film) to 10–15 years (polycarbonate).

Anti-Corrosion Treatment

Even in dry desert air, condensation inside the greenhouse and occasional humidity from cooling

systems can cause corrosion over time. Hot-dip galvanizing after fabrication (rather than pre-galvanized

steel) provides the most durable corrosion protection. All fasteners, brackets, and connectors should

also be galvanized or stainless steel.

Real-World Experience: The Abu Dhabi Project

Theory is valuable, but nothing replaces hands-on experience. Shouguang Clover Agricultural Facilities

recently completed a significant greenhouse project in Abu Dhabi, United Arab Emirates — five arched

greenhouses covering 34 acres. This project demonstrated several key lessons:

1. Arched greenhouse design performs well in desert conditions: The arched roof profile handles wind loads

effectively and allows for efficient film or polycarbonate covering.

2. On-site installation matters: Clover sent installation personnel to Abu Dhabi to supervise and participate

in the assembly, ensuring that the structures were built to specification and commissioned correctly.

3. Local climate adaptation is essential: The cooling and ventilation systems were specified based on Abu

Dhabi’s climate data — not generic specifications — to ensure adequate performance during peak

summer.

This project, along with others in Saudi Arabia, Pakistan, Brazil, and Turkey, underscores the

importance of choosing a manufacturer with actual desert greenhouse experience — not just theoretical

knowledge.

Internal link suggestion: View photos and details of our international engineering cases on our

showcase page.

6/7Conclusion

Building a greenhouse in the Middle East is challenging but entirely feasible with the right engineering

approach. The key success factors are:

Proper cooling system design — pad-and-fan evaporative cooling, sized to local climate conditions

Appropriate covering material selection — polycarbonate for insulation and impact resistance, or glass for

maximum light transmission

Efficient water management — drip irrigation, fertigation, and condensate recovery

Robust structural design — galvanized steel, aerodynamic profiles, and UV-stabilized materials

Experienced installation — a manufacturer that can send teams abroad to build the greenhouse correctly

For buyers in Saudi Arabia, the UAE, and other Gulf countries, partnering with a manufacturer that has

completed desert greenhouse projects and provides overseas installation support is the single most

important decision you can make