Integrated design

How can you achieve good indoor air quality and energy efficient operations? Reem Emirates Aluminium demonstrates an integrated approach at its new headquarters.

Gaining maximum energy efficiency and a good indoor environmental quality simultaneously is a primary goal of any new building, particularly if it is to meet the green building standards being applied worldwide today.

Achieving this goal is not always an easy task, but Reem Emirates Aluminium believes it can be met by use of its integrated approach to heating, ventilating and air conditioning (hvac). The firm is currently putting its proposed solution into action on its own new headquarters building in Abu Dhabi.

Based in the industrial Musaffah area of the city, the firm's four-storey headquarters is scheduled for completion in March 2008. The crescent-shaped building is being built directly onto the firm's existing warehouse facility and will have a fully-glazed facade that will form a central part of its energy efficient operation.

And Reem is not just purely speculating about the success of its solution. Across the car park from its new headquarters sits an unassuming looking building. From the outside it could be a caretaker's house or storeroom, but step inside and you will come face-to-face with an advanced integrated hvac solution.

The building is in fact a full-scale mock-up that was constructed to test and fine-tune the integrated system. Measuring around 6x6m, it is equivalent to the standard area for four office desk spaces.

Reem describes its solution as a fully integrated, intelligent and energy saving mechanically ventilated double-skin green wall. The overall system includes an active facade, chilled beams, underfloor cooling, light emitting diode (LED) lighting and motorised blinds - all controlled by a complex building management system (bms).

The firm's motivation was to form a true green hvac building solution and launch active facades into the Middle East market reports Reem Emirates Aluminium r&d engineer Imthias Mohamed.

"The company's main focus was to be a next generation curtain wall designer," explains Mohamed. It established an r&d division in September 2006 with a focus of developing a curtain wall that integrates with other building hvac systems. With its headquarters underway, the firm decided to construct the mock-up building to ensure that the proposed solution would work in practice.

"The main concept is to conserve energy consumption," stresses Mohamed. "The system addresses the two major categories of [US Green Building Council's Leadership in Energy and Environmental Design rating system] LEED: energy and atmosphere, plus indoor environmental quality (IEQ). These give a total of 32 points under LEED, which is about 46% of the points straightaway," he adds.

The concept involves creating a constant temperature throughout the room to increase occupant comfort, hence productivity; and achieving this temperature through the minimal use of mechanical energy. The technology and products used in the system was existing; what is new is the use of some components in the Middle East's environmental conditions, plus the integration of the individual products to make a single operating system.

MEP consultant Deerns Middle East carried out a series of cfd modelling and calculations to ensure that the systems could be effectively integrated. "In integrated solutions the design is very important as each part has to be balanced with one another," stresses Deerns Middle East director Hans Hamer.

Creating the desired temperature while eliminating the build-up of condensation on the chilled beams and underfloor cooling system was one of the biggest challenges for the design team.

This was overcome by a series of tests that determined the precise mix of chilled water flow rates and air flow rates that were needed through the various equipment to meet the desired setpoints. From the results of these tests and experiments a series of formulas were created that are used to operate the bms.

Installation of the system is simple and needs no specialist training, assures Mohamed and the payback time is less than three years due to the reduction in energy use that would be achieved.