On a salt flat outside Abu Dhabi, Masdar City is beginning to take shape, starting with a university and a bunch of energy experiments.
The Masdar Institute, a post-graduate research academy, is the site of a number of investigations into energy efficiency, some involving architecture and infrastructure, and others focusing on human behaviour.
The apartments housing the 153 students now living on campus are extensively wired to metre the energy used by everything from air conditioners to toasters. Movement sensors can send instructions to the wiring system to turn off appliances in rooms that are not in use. All the appliances come with the apartment and have been vetted for energy efficiency. To maintain those standards, students need approval from the building manager to bring other appliances onto campus, explains Martin Potter, the director of operations and facilities at the Masdar.
Between the laboratory wing and a block of student apartments stands a modern take on an ancient feature of Gulf coast architecture: a wind tower. Inside, a ceramic coil takes the place of the traditional cloth membrane that separates rising hot air from a cooler current of descending air. On each rising edge of the slim truncated tetrahedron is a sensor panel that can indicates, by lighting on a spectral scale from green through yellow and orange to red, how successfully the building is conserving energy.
One social experiment is to test how the students respond when the indicator panels show red. Mr Potter has access to energy consumption data for each individual apartment and says he is prepared to "name and shame" wastrels.
Another feature of the Masdar Institute is its rooftop photovoltaic (PV) panels. In total, these form a grid-connected array with an installed capacity of about one megawatt.
The PV panels are experimental in the sense that Masdar, the Abu Dhabi government-owned clean energy company developing
, is reassessing an earlier plan to equip all buildings in the eco-city with rooftop PV.
Whether or not that will eventually happen depends on hard economics. On the one hand, rooftop PV is up to twice as expensive to mount and maintain as ground-level panels. The need for regularly wiping off the fine dust that settles on the panels in this part of the world is a large consideration. On the other hand, land prices are high this close to the UAE capital.
To be sure, Masdar City already has its own 10mw solar PV farm, which was connected to the Abu Dhabi power grid two years ago and at the moment contributes more power to the grid than it draws.
"In fact, we hesitated to allocate this land," says Dr Afshin Afshari, the energy manager for Masdar City. "But in the middle of the desert, it is definitely cheaper to build solar farms."
That is just as well, as Abu Dhabi's sector of the Rub al Khali, or Empty Quarter, is not known to harbour many large, flat-roofed buildings.
In Masdar City, however, the current plan calls only for rooftop PV at the Masdar Institute and at the yet-to-be-built Masdar headquarters building, which should have 3mw of capacity installed by 2014.
Masdar City has two other small solar arrays, both pilot projects that provide platforms for the Masdar Institute's students to conduct engineering experiments.
The first project is a partially built 100 kilowatt concentrating solar power (CSP) plant that employs a novel design dreamt up by engineers at the Tokyo Institute of Technology. The Masdar Insitute's students now have the task of optimising the design for local operating conditions.
Like a commercial CSP plant, this one consists of an array of movable mirrors that track the sun and reflect sunlight onto a "receiver", from which the concentrated energy can be focused onto a boiler containing water or a salt solution. The hot fluid can be used for a number of purposes including heating, cooling or power generation.
"What's different is that in a normal CSP plant you have a tower with a receiver on the top. But in this plant, what you have on top of the tower is another set of mirrors that reflect light onto a receiver on the ground," says Zayid Tahboub, a student at the Masdar Institute. "Having the receiver at ground level makes it easier for maintenance."
But at the moment, there is no receiver or boiler installed here. The students' task is to try out various possible technologies and configurations for those components and select the one that transfers energy most efficiently.
The second Masdar City pilot is a solar cooling plant. It uses the same technology as a standard CSP plant to heat up a lithium bromide solution to a temperature of about 180 degrees C. The hot fluid is used to start a chemical reaction that efficiently evaporates water, resulting eventually in another supply of water inside pipes being chilled to about 7 degrees C. That is sufficiently cool to run an air-conditioning unit for a large institution such as a college or a hospital.
"Cooling is one of the major demands in this city. That's how we can justify an installation such as this to target a specific application," says Simon Braeuniger, the project manager for the pilot studies. He also was a principal designer of the solar chilling plant.
The Masdar City district-cooling pilot may be unique. Potentially it could become one of the first marketable technologies to emerge from the eco-city.
"Chilled water as a solar power application is really new," says Mr Braeuniger. "If this technology turns out to be competitive, which is what we believe, there would be a niche market developing for it."
If he is right, then the UAE may become the first country to boast solar-powered rooftop air-conditioning systems.
