Solar Air Powered Air Conditioning Comes To Dubai


Doesn't look like much from the top; ESAB building, from Construtionweekonline
One of the reasons we have been so dubious about Dubai is the energy consumption required to keep people cool there; they even air condition the beaches. But if there is one thing they have lots of, it is sunlight; that's why we have always considered solar powered air conditioning the holy grail that will make places from Dubai to Phoenix sustainable.

Now ClimateWell of Sweden has installed a working solar air conditioning system at the ESAB offices and warehouse in Dubai. ESAB is a worldwide welding equipment and supply company, and the building is considered by Construction Week to be one of the Middle East's five best green buildings.

Most solar air conditioning ideas we have shown were used ammonia based adsorption systems, which predate conventional air conditioning. ClimateWell developed a "Triple-State absorption technology using salt and water."

If you follow the animation a few times it becomes clear that hygroscopic salts absorb a lot of water vapour, which absorbs a lot of heat when changing state from liquid to gas. Then it takes heat to get the salt to give up the water, where the solar comes in, to cycle the water back so that it can evaporate again. In case I got that wrong, here is their more technical writing:

A chemical heat pump is based on the principles that water molecules bind more efficiently to certain hygroscopic salts than to other water molecules. As a consequence, when using two separate bowls - one containing water (evaporator), and the other containing hygroscopic salt (reactor) - in a confined space, water will evaporate to the salt that absorbs the water. When the confined space is in a state of vacuum the water transport will be so high that the water will start boiling in order to produce vapour at the same speed as it is absorbed by the salt. Such evaporation requires energy. If the energy is not supplied from outside the system it will be taken from the water itself, which as a consequence gets colder. In essence the evaporation process transports thermal energy (heat) from the water to the salt. The temperature difference increases until a maximum difference (∆T), at which the salt is no longer able to absorb more water.

There is more than enough solar energy to meet all of the cooling and heating needs, of either a house or an office building.

Read More: Green Materials Guide to Heating and Cooling

Thomas Bohlen, chief technical officer at the Middle East Centre for Sustainable Development (MECSD) in Dubai says in ConstructionWeek:

"The best bit is the building's solar thermal cooling system, which uses a roof-mounted solar tube collectors to provide hot water to six absorption units, that in turn provide cold water to air handling units on the roof. Cold air is then circulated through the concrete pre-cast, hollow core ceiling slabs of the office, providing cool air and radiant cooling. The way this system is woven into the building structure is a great example of how early commitment by the stakeholders to sustainability can make for a great building.....This project has proven that even industrial buildings in the Middle East can be designed, constructed, and operated to the highest current standards of sustainability.""

We have requested more pictures and information and will update when they become available. Via a ClimateWell press release.
Other TreeHugger posts on solar powered air conditioning:

1. Solar Powered Air Conditioning Just Makes Sense


Some concepts just make sense- like when the developer of a solar powered pontoon boat pointed out-"Since most recreational boating is done when the weather is nice, solar power is particularly well adapted to the task." We were thinking that way while looking for a solar powered air conditioner- when do you need it? When it is hot and sunny. We looked at Justin's SolCool but we knew that natural gas fired AC units or propane fridges existed and thought heat is heat- there must be one somewhere, and put google to work. This is the first of a series- the Direct-Fired Absorption system.(DFA)

More in TreeHugger

2. Challenge: Build the Solar Powered Air Conditioner


We continue to be fascinated by the idea of a solar powered air conditioner, particularly after reading this in Alternet. Until central air became common, Florida and Arizona were barely habitable- you went in winter and cleared out. Now 20% of our energy goes to power air conditioning, and it defines the peak loads. 5.5% of our gasoline goes to power our car air conditioning, and four southern states-California, Arizona, Texas and Florida, account for 35% of it. Clearly if we are going to use less energy we have to address this problem. So here is a challenge to all you Lifehacker and Make types- build it for us. And not a lame ice-cooled pretend air conditioner but the real thing. Here are some ideas and parameters:

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3. The Sun Lizard - Solar Air Conditioning



Asks an Australian if they've been busy or not, and they might reply, "Mate, I've been flat out. Like a lizard drink'n." Colin Gillam, CEO of Alternative Fuels and Energy may well give just such an answer regarding his Sun Lizard solar heating/cooling project. Especially as he has been working on it for the past 16 years. His persistence finally paid off when last month he was scored both the judge's vote, and the people's choice vote on the ABC New Inventors TV show.

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4. Coolerado Coolers: Getting Close to Solar Powered Air Conditioning


We are intrigued by the idea of solar powered air conditioning; it is just so logical as you need it most when the sun is blazing. Right now the heavy-handed approach is to spend a lot of money on photovoltaics to run conventional units; there has to be a lower cost, more efficient way.

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5. Small-Scale Solar Powered Air Conditioning Is Here (in Spain, Anyways)



For years we have been saying that solar powered air conditioning just makes sense- if you are boiling in Phoenix the sun is probably shining really hard. We have seen big units, evaporative units that won't work in humid climates, a few vaporware units and even home-made absorption chillers

Now it looks like a Spanish company, Rotartica, has put it all together, by combining evacuated tube thermal collectors with a water-heated absorption chiller, and sized it at 4.5Kw (1.28 tons) for residential use, all packaged in a neat little box.

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6. Finally a Solar-Powered Air Conditioner: 6 Tons of A/C Using 4 Solar Panels



Finally a Workable System to Replace Current Energy Guzzling A/Cs?
In 2007 we covered a Coolerado A/C system with the headline "getting close to solar powered air conditioning". Back then, the unit produced 5 tons of cooling using 1,200 watts, getting within the range of what some people and small businesses could afford in solar panels. Now, the new Coolerado design can produce 6 tons of cooling using 600 watts, quite an impressive improvement!

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7. Steinway Installs Solar-Powered Air Conditioning



Solar-powered air conditioning just makes so much sense; it is usually hottest when the sun shines brightest. Now piano maker Steinway has installed an 80 ton absorption chiller that is powered by hot water from tracking solar panels. In the winter, the solar collectors provide water for heating.

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