The Energy Commission’s Diamond Building is a standout among the sea of government offices in Putrajaya, in more ways than one. By visual experience, anyone would describe the country’s administrative capital with the wide expanse of roads and buildings which are mostly brown concrete ones that all look similar, exceptional to one greenish glass upside-down pyramid shape building with the top buried in the ground. Little that many know it is actually one of the most energy efficient, multi-award winning office building in South East Asia.
The (Suruhanjaya Tenaga) ST Diamond building is a green building landmark in South East Asia that is designed to showcase technologies that cut down energy consumption and potable water usage, promote the use of sustainable building materials and provide enhanced indoor environmental quality. It is a physical evidence reflecting the determination of the nation’s regulatory body for energy policies, standards and safety implementing arm, Energy Commission to prioritize energy efficiency during 2005 then. However, this double Platinum-rated building has proven itself to be more, as global sustainable community recognizes it as an international standard of showcasing sustainable office building design in the tropics.
With just an additional cost of 6%, the ST Diamond Building carries two Platinum Certificates, each one from Malaysia’s Green Building Index (GBI) and Singapore’s Green Mark. Besides scoring from the green building rating tools from both countries, the ST Diamond Building also carries several awards such as, the global ASHRAE Technology Award 2013 (2nd place) and regional ASEAN Energy Award 2012, testifying that it’s innovative design has earned recognition internationally.
BENCHMARKING THE BUILDING ENERGY INDEX
The building has an building energy index (BEI) of 65 kWh/m2/year (excluding Solar PV) at annual operation of 2,800 hours – a 70% reduction in energy consumption compared to a typical building office in Malaysia with an average BEI of 210 kWh/m2/year, which majority of them scores BEI of between 200 and 250. The overall BEI is determined by several factors ranging from passive design, active design, and management system during operation.
The unique shape of the ST Diamond Building was designed according to the climate and solar path of equatorial Malaysia. Solar studies showed that the 25° tilt angle of the facades can ensure that North and South facades are fully self-shaded throughout the year, while it reduces the solar impact by 41% for the East and West facades.
To maximize daylighting, a central atrium was introduced and the diamond shape takes form. Meanwhile, the diamond reflects Energy Commission’s role and mission as a regulatory body significantly for its transparency, value, and durability. The building includes seven floors above grade and two underground levels for parking. Low-e-glazing with Solar Heat Gain Coefficient (SHGC) of 0.37 ensures direct solar heat will be reduced, while the glazing’s visual light transmittance (VLT) of about 50% allows for effective diffuse light to the office interior. The inverted diamond shape also increases the ground space available for landscaping, which helps reduce the heat island effect and also and allows glare-free diffuse light to be reflected off the landscape.
The ST Diamond Building is designed 50% daylit, without glare and minimal heat entry, This is achieved through extensive façade daylighting system simulation to able deeper daylight penetration. With the usage of mirror light shelf, white painted window sill, white ceiling and no interior partitions and no suspended ceilings, the daylight distribution is improved until 5 meters from the façade + 2 additional meters of corridor space. Fixed white louvers with top surface mirror finish on the top side are mounted with a 30° tilt angle above the light shelf for glare protection while still allowing daylight to be deflected onto the ceiling.
The atrium has been carefully designed to optimize daylight utilization for each floor employing the combination of the following three strategies:
- Automated blind with six different configurations to maintain the appropriate daylighting levels at all times. The blinds with 30% light transmittance are adjusted every 15 minutes and follow a three different control strategies for morning, mid-day and evening
- The windows size becomes larger deeper into the atrium to cater for lower daylight levels
A band of Tannenbaum reflector panels is applied to 4th and 5th floor to deflect daylight across the atrium to 1st and 2nd floor where daylight levels are the lowest. The ‘christmas tree’ profile reflectors have an inclination of 10° and reflect about 85% of the light in a semi-diffuse manner, hence, avoiding visual glare issues for the building occupants.
Smart Artifical Lighting system
The ST Diamond Building office space uses ceiling suspended with electronic ballasts and T5 tubes. However, since the lighting system is daylight responsive by integrating lux sensor into the building automation system, the installed lighting load of 8W/m2 is able to be drop to 0.9W/m2 during operation when the set point of the general lighting is reduced 150lux instead of 300lux as required by MS1525. This is possible, as all occupants can compensate with an individual task light when needed, though most people prefer lower light levels (50-100lux) when doing computer work. These lighting controls result in more than 90% lower than the 15W/m2 baseline of MS1525. A research has shown that this could reduce energy consumption, increase the daylight responsiveness of the building without sacrificing visual comfort. All work tables have individuals task lights, providing further ergonomic benefits by allowing individual lighting control. A survey among the occupants showed a high level of satisfaction of the hybrid lighting system consisting of daylighting, general lighting and task lighting.
Floor Slab Radiant Cooling
Another unique point about the ST Diamond Building is the floor slab cooling system. The radiant cooling from the floor slab is achieved by cooling the reinforced concrete floor slabs with chilled water by 19 degrees Celsius using polyethylene-reinforced thermal pipes embedded in the concrete slab. The concrete slabs act like a thermal storage, which will be charged every night from 10 p.m. to 6am and be cooled to around 22°C. During the day-time, the system is shut off, and floor slab passively absorbs heat gains from people, computers, solar gains etc. During the day, the floor slab increases its temperature by about 1°C only to be cooled down again the following night.
By doing so, this reduces cooling transport energy by 64% because it is more efficient to transport cooling with water than with air. Also, with much of the cooling being shifted to the slabs, so the AHU system can be down-sized about 30%. By shifting 30-40% of the cooling to night time, the ST Diamond can save cost from the lower off-peak energy rates and from reduced maximum demand charge. In fact, the building management system was used to reduce the peak demand by another 50% by sequencing the start-up of the AHUs.
The monitored ceiling surface temperature is constantly 2°C or higher than the dew point of indoor air, this ensures no condensation will form on the ceiling surface.
Energy Efficiency and Renewable Energy
Emphasis is also made on energy efficient office equipment. A procurement policy allows for the purchase of only energy efficient labelled equipment and appliances with five star Energy Start ratings. The ST Diamond Building also has 71.4 kWP of Thin Films Solar Panels integrated into the roof which reduces the buildings energy consumption by 10%. The thin film solar technology is suitable for the tropical climate, as this type of solar cells is better at capturing diffuse light than conventional solar panels – and thin film solar cells also experience less of a drop in energy efficiency when baking under the hot sun. Their measured annual yield is 1400 kWh/kWp, which significantly higher than conventional solar PV (1150 kWh/kWp). The generated electricity is connected to national utility’s grid under the Feed in Tariff Scheme (2012). With such, the solar panels have generated a monthly average of 8,300 kWh and annually about 100,000 kWh.
Internal Air Quality and Thermal Comfort
A green building puts equal amount of attention on occupants’ well-being too. By using low-VOC paints and carpets, which are certified by Green Label certification, the total volatile organic compounds parts per billion is sufficiently low to satisfy the indoor air quality criterion. A 12 month post occupancy comfort survey was carried out to collect occupants’ responses regarding thermal comfort, glare comfort and odor problems. The result is over 80% of the occupants expressed satisfaction. The thermal comfort is addressed by the usage of CO2 sensors that regulates the demand control variable air volume (VAV) ventilation system. IAQ measurements throughout the different levels of the building indicates the CO2 parts per million (ppm) is less than 500 ppm, hence, giving the occupants plenty of fresh air, as the maximum limit is 1000ppm. The basement car park is natural ventilated through the sunken garden and equipped with carbon monoxide and temperature sensors in the event if mechanical ventilation is needed. However, observations have shown that it is virtually not used, as the natural ventilation is normally sufficient.
The ST Diamond Building also boasts its extensive water saving strategies. By using rainwater for toilet flushing and irrigation, annual potable water consumption has been reduced by 35% compared to potable water otherwise used for industry standard water fittings and irrigation as defined by the Green Building Index. The rainwater is collected from the 700m2 catchment area and stored in four 2,600 gallons (10,000 liters) rooftop tanks.
Also, all water from the sinks and floor traps (gray water) is piped separately through a sand filter to a collection tank from where it is reused for irrigation of a mini wetland instead of going to the sewerage. 2000-3000 liters of water are recycled every week day. The usage of water efficient fittings is able to reduce the potable water usage by more than 67% compared to conventional plumbing fittings.
Acknowledging the significant amount of carbon footprint per household in transportation, which is 68%, green buildings such as ST Diamond Building is designed to address solutions for occupants to have alternatives towards a lower carbon footprint of transportation. As such, 2 Electric Vehicle charging stations are available, ten percent of parking garage spaces are designated for green/fuel-efficient vehicles and carpool vehicles; secure bicycle racks; location served by public transportation and shaded walkways for pedestrians linking to the master development.
Environmental Impact and Cost Effectiveness
In a nutshell, the operational carbon (CO2) reduction achieved by the ST Diamond Building amounts to 1,673 metric tons per year, which is akin to taking 900 cars off the road (assuming each car travels 12,000km/years). This reduction is derived from savings of electricity alone and does not include reduction due to water savings, waste discharge, refuse recycling, embodied carbon and savings from district cooling consumption of the building. The building’s eco-friendly measures cost about RM3.5 million, representing about 6% of the total construction cost. Savings of almost RM1 million annually in operating costs from energy efficiency and solar power generation, this resulted in an estimated payback of 3.5 years despite Malaysia’s subsidized utility tariff rates.
The ST Diamond Building has been operating for 3 years since the completion and occupancy during mid-2010. It is learned that the maintenance team has been maintaining the green features of the ST Diamond Building well and also educating the staffs more about the building they are working in. It is vital that the users could adapt to such green building environment and understand how it works in order for the building to achieve its purpose which is using lesser energy. The ST Diamond Building is a physical demonstration landmark that has served as a milestone to chart Malaysia’s determination towards sustainable development and smarter, energy efficient buildings.
Equally important, the ST Diamond building has demonstrated the financial viability of green buildings. By cutting the energy consumption down to 1/3 and with a payback of only 3.5 years, the ST Diamond Building has shattered the commonly held misconception that “Going green is expensive”. Instead, the ST Diamond building, which annually saves RM1 million operational costs, has proven that “Not going green is expensive”.
This Article above is also printed out Green+ Magazine edition October 2013.