Dubai to launch Dh7m farm cooling systems that halve amount of water used

DUBAI // A Dh7.3 million project to halve the amount of water used by agricultural cooling systems through redesign is to begin in January.

Dr Naem Mazahrih, an irrigation and water management specialist, said the amount of water used in greenhouses to keep plants cool was much higher than the amount used to sustain them.

“This is the main problem facing protected agriculture in the Arabian Peninsula,” said Dr Mazahrih, of the International Centre for Agricultural Research in the Dry Areas in Dubai, which is handling the project.

Depending on the season, water use for cooling greenhouses can be five times higher than the amount consumed by the plants in the greenhouses, he said.

“Protected cultivation doesn’t save water,” Dr Mazahrih said. “So we want to try three to four types of different cooling systems.”

Cooling systems use evaporation pads that cool outdoor air by between 5°C and 10°C.

“It’s not a lot and it uses a lot of water,” he said. “Water goes through the system, cools it and it evaporates, which makes cold air.

“But we need to try different experiments to avoid using any water. There’s pressure on the groundwater, which is important for the future.

“It will eventually become saline and there’s no rainfall to increase it, so we need to save every drop of water and use it as efficiently as we can.”

One way of doing that is to reduce the temperature of the water going through the evaporation pads. Another is recirculating the air between different greenhouses.

“Outside it’s 50°C but if we circulate the air between different greenhouses, that will reduce the evaporation from 50 per cent to 30 per cent, depending on the plant,” Dr Mazahrih said.

“There’s a lot of humidity inside the greenhouses which can create diseases to plants, such as wilting, so we need to reduce the evaporation in building.

“The new system will condense the air to reduce the humidity, so we’re using water from the humidity in the air.”

The centre plans to use solar energy to power the systems.

“We want to compare how much water we can save,” Dr Mazahrih said.

“We will test these methods on a farm at the Ministry of Environment and Water’s research station in Hamraniyah, near Ras Al Khaimah, and we expect preliminary results in the first two years.”

If successful, the three year-programme will expand to other farms in the UAE and the region.

“In the past we found that cooling systems consumed too much water, so if we can reduce it we can plant more with the same amount of water,” he said.

“We’re hoping to reduce it by 10 to 50 per cent.”

Agricultural experts said cooling was an important element for fresh produce, given the high temperatures in the region.

“It’s an area that can potentially deliver significant improvements, in terms of efficiency and effectiveness,” said Nicholas Lodge, an agricultural expert at the Abu Dhabi consultancy Clarity.

“Any research in the sector is welcome and, given the highly stressed environment in this region – notably the lack of water, arable land, growing population and increased meat consumption – the sooner the better.”

Mr Lodge said making use of resources that were abundant in the region, such as seawater and sunlight, could lead to more sustainable approaches.

“But it is also important not to lose sight of the big picture, and a holistic approach is ultimately what is needed,” he said.

“We should also look at whether certain agricultural activities or crops still make sense, or whether we should curtail these and redeploy precious resources in other ways.

“High-value, perishable produce, like herbs and lettuce, lends itself to intensive production using technology that can address the issues that come with this region’s climatic conditions.”

cmalek@thenational.ae