DUBAI // A system that uses solar energy to cool an office-warehouse complex in Dubai has cut its electricity consumption by 60 per cent.
Now the company behind it is preparing to launch five more such projects in the next two years.
Applied to residential buildings, the system could slash power bills, especially during the summer peak: 70 per cent of the UAE’s electricity consumption powers air-conditioning units.
The solar-powered cooling system was installed last May at ESAB, a Swedish company that manufactures welding and cutting equipment at the complex in Jebel Ali.
The unit cools 5,500 square metres of office and warehouse space to between 22°C and 24°C.Johan Fransson, managing director of ESAB Middle East, said that besides achieving a comfortable temperature, the system was quiet. “We are extremely happy with the concept,” he said.
The building has several other “green” features, including use of natural light, a plant to recycle water and sensors that turn off lights as occupants leave.
They added five per cent to the cost of the building, which Mr Fransson expects to recoup in energy and water savings within five years.
The air-conditioning technology used at the ESAB building relies on solar thermal collectors provided by an Irish company, Kingspan Renewables. The thermal panels use non-porous glass tubes, meaning they collect less dust than some other devices, overcoming one hurdle to uptake specific to the region.
The collectors cover an area of 160 square metres on the roof of the building, where they transmit heat via copper wiring to stored water. The water is heated up to 100°C, activating a device that prompts several chemical reactions, chilling the water to 10°C.
To cope with the UAE’s extreme summer temperatures, the system does incorporate a small chiller that runs on electricity. It is used at night to cool down the building’s concrete walls, which then warm up very slowly.
“We are using the building as thermal storage,” said Lars-Olof Johansson, director of the Swedish company Dew-Kylsystem, which installed the cooling system.
The concrete walls act as an insulator for the building, preventing heat gain from the exterior and reducing strain on the solar cooling system.
The concept was originally developed in Europe for use in heating systems. “The new thing today is that we are combining it with solar-powered chillers,” said Mr Johansson.
It is too early to give details of the five new planned projects, he said, but one would use solar energy to cool up to 10 buildings.
As with any new technology, potential clients need to see evidence of a functioning system before they decide to invest. “It is important to have a reference site,” Mr Johansson said.
In the UAE most solar projects focus on generating electricity. Another solar cooling unit is in operation at the headquarters of Pacific Control Systems in Dubai, and engineers at Masdar City in Abu Dhabi are testing their own scheme.
The UAE has so far been slow on the solar cooling front. Such systems require long-term planning and are more expensive to install.
If developers take a long-term view and consider operating costs rather than just installation, solar cooling becomes a more attractive option, said Gerard Whelan, managing director of Kingspan Renewables.
“Although it is green energy in its purest form, it is also good business,” he said. “One advantage is that there is a direct match between increased solar radiation and the demand for cooling.”
Mr Whelan said that the Government could encourage the industry through green building regulations, limiting the energy intensity of buildings.
Abu Dhabi has started putting some requirements in place, but so far it is the only emirate to do so.
