Ancient artefacts meet new technology

Singapore’s newest museum has raised the bar on energy efficiency thanks to Mott MacDonald’s award-winning design cutting energy demand by 28 per cent. By Joe Ong

Singapore’s Indian heritage is being celebrated by a new museum that has literally set new standards for sustainability. The £5.5M Indian Heritage Centre (IHC), located in Singapore’s ‘Little India’ neighbourhood, contains three gallery floors dedicated to Indian artefacts, culture and history. Singapore’s diverse Indian communities number over 350,000 people and form a major proportion of the national population.

Mott MacDonald was engaged by Singapore’s National Heritage Board to provide building services engineering and sustainable design consultancy in pursuit of a Green Mark Gold Plus award under the country’s Green Mark sustainable building rating system. The consultancy’s response to that task was a set of design solutions that reduced the building’s overall energy use by 28 per cent compared to a code-compliant building, and cut operating costs by SG$45,500 (£22,000) annually.

The fundamental challenge facing Mott MacDonald was to reconcile the need for precise 24-hour environmental control to safeguard the museum’s centuries-old artefacts with the need to minimise energy consumption. In a hot and humid climate like Singapore’s, air must be overcooled to remove moisture, then reheated to achieve the best balance of air temperature and relative humidity for human comfort. To enable humidity control without the use of mechanical reheating, the consultancy designed a means of recycling heat from the intake air.

Humidity control with 44 per cent added efficiency
This system works by placing heat exchanger coils either side of the main chiller coil. They are linked in a closed loop, separate from the main system.

The first coil contains cold heat transfer fluid which precools incoming fresh air before it reaches the main chiller coil. The transfer fluid is heated by this process and travels to the second coil where it in turn reheats the now-overcooled air. The transfer fluid becomes cold in this process, and so it recycles back through the loop. Mott MacDonald’s system is 44 per cent more efficient than one using a heat pump at the reheating stage.

This is because all the hard work is done by the main chiller, which is driven by a highly energy efficient centrifugal compressor. Magnetic levitation is used to eliminate friction between the compressor shaft, which rotates at very high speeds, and the shaft’s support. This creates over 37 per cent greater energy efficiency than a conventional chiller.

To save more energy at night, Mott MacDonald devised an innovative ‘superdehumidification’ process. The chiller is configured to produce very chilled water for a short period before being shut down for a number of hours overnight while the already-chilled water continues circulating. Through rigorous testing, the consultancy showed that this mode of operation meets temperature and humidity requirements while using less energy.

Mott MacDonald worked with the architect and façade consultant to further improve building envelope performance by incorporating a double-skin façade that significantly reduces thermal gains and solar radiation. Mechanical fans at the top of the façade space help to induce stack effect ventilation, reducing the overall need for mechanical ventilation.

The double-skin façade also improves acoustic insulation and the inclusion of staircases provides a circulation space for visitors to move between floors. Locating these staircases in the façade freed up extra floor space for galleries and raised floor plate efficiency to 90 per cent, surpassing the National Heritage Board’s requirement of 82 per cent.

Exhibit lighting cuts energy demand by 24 per cent
Lighting was another opportunity to save energy. By persuading the gallery consultant that halogen exhibit lighting could be replaced by LEDs, Mott MacDonald delivered a 24 per cent saving in lighting energy consumption.

Social sustainability was crucial. The community was reflected architecturally, with Indian sculptors commissioned to carve decorations for the entrance projection and the façade staircases designed to resemble traditional Indian architecture. Following extensive community consultation, the road fronting the IHC was converted into a pedestrianised space for community use.

The consultancy was successful in achieving Green Mark Gold Plus – after overcoming a final hurdle. Existing benchmarks were not applicable to a museum environment with strict environmental control requirements, so Mott MacDonald worked with the local building authority to allow the IHC to be assessed appropriately, by developing alternative baselines for elements such as gallery lighting and air delivery systems.

As a result, the IHC remains Singapore’s only museum to date to have achieved this sustainability award. The new baselines Mott MacDonald helped develop, as well as the design example set by this project, will pave the way for other Singaporean museums to realise similarly high standards of sustainability in future.

Joe Ong is principal engineer, Mott MacDonald.

For more information, please see www.mottmac.com