Asian Development Bank Lights the Way in Efficiency
Asian Development Bank Lights the Way in Efficiency
When the Asian Development Bank headquarters building was
designed in the 1980s it was considered a very energy-efficient building.
Only a decade later, however, actions taken have profitably reduced its
energy use by more than one-third.
The Asian Development Bank (ADB) headquarters building in Manila, the
Philippines, is living proof of the potential for substantial energy savings
in commercial buildings. When the building was designed in the 1980s,
it received an energy-efficiency design award from the American Society
of Heating, Refrigeration, and Air-Conditioning Engineers (ASHRAE). However,
despite the fact that the building was fairly modern, actions taken over
the past six years reduced its energy use by nearly 40% and generated
an internal rate of return of more than 25%. The ADB building now has
an important demonstration value for ongoing efforts in the Philippines
and Asia to promote energy-efficiency investments in commercial buildings.
In 1993, the electricity bill of the ADB headquarter building exceeded US $2 million per year, and the monthly bill averaged around $180000. The two largest components of the bill were lighting (35%) and cooling (50Ð60%). Some of the other major end uses of electricity - all of which consumed less than 5% each - were computers, the restaurant, refrigeration, elevators and transformer losses.
FROM HOUSEKEEPING TO INVESTMENTS
Beginning in 1993, ADB began efforts to improve the use of energy in its headquarters. As part of this effort, the Building Maintenance Section undertook housekeeping measures and several projects to optimize the existing equipment. These efforts resulted in an 11% reduction in the buildingÕs energy consumption. In 1994, ADB commissioned a detailed energy audit by the International Institute for Energy Conservation (IIEC) and Supersymmetry (of Singapore) to evaluate the potential savings of an additional set of more aggressive energy-saving measures. The measures considered in the study ranged from no-cost and low-cost measures to more significant retrofit investments. Based on discussions with ADB staff, it was assumed that the Bank would only consider energy-saving opportunities with a return-on-investment (ROI) of greater than 12%. The measures analyzed in the study had ROIs ranging from 19% to 137%.
ADB budgeted $3.5 million for the retrofit project. As of December 1999, committed expenditures were approximately $3.3 million. The overall savings generated to date through the completed project components is more than 30000000kWh, or $3.43million in reduced electricity costs until December 1999.
COOLING EFFICIENCY MEASURES
The largest share of the savings was achieved through improving the efficiency of the buildingÕs cooling system. The energy management system and building monitoring system are important aspects of making the cooling system work well. Important investments were made in the downsizing of refrigeration chillers and the replacement of the CFC gas with an ozone-friendly alternative. The combined annual savings for these measures are expected to be over $219000. The new chillers have also been fitted with automatic tube cleaning equipment, which maintains tube heat transfer efficiency and reduces maintenance downtime. The cost of this equipment is $60000 and, through improved chiller efficiency savings, the payback period is estimated at three years.
The pumps for chilled water and condensed water were also replaced with new, more efficient pumps. These measures generated savings of approximately $73000 annually. The retrofit of the building's cooling system also involved improvement to the cooling towers.
LIGHTING EFFICIENCY MEASURES
Investments in energy-efficient lighting represent the second most important set of measures. The lighting savings generated direct savings in reduced electricity demand, but also generated indirect savings through reduction in cooling requirement, since the more efficient lighting systems generate less excess heat.
The single most important measure was the replacement of basic lighting installations, where the building designer specified non-standard fluorescent lamps and luminaires. Due to the unavailability of 1160 mm energy-efficient fluorescent lamps on the international market, an exercise was undertaken to modify and lengthen existing features to 1200 mm, enabling the high-efficiency, 32-watt T8 fluorescent lamps to be used with one electronic ballast instead of the existing two magnetic ballasts. This measure realized annual savings of $135000. All 5 880 downlights in the building were retrofitted to use CFLs, a measure that realized annual savings of $110000.
Occupancy sensors were widely used in the retrofit: A total of 960 passive infrared occupancy sensors were installed in office areas throughout the building. In addition, a further 1050 ultrasonic occupancy sensors were installed in the office areas, conference rooms and service areas. The annual saving for this measure was $35000. In addition, all 700 exit signs in the building were retrofitted. Here, the 40-watt fluorescent lamp signs were replaced by 1.3-watt LED (light emitting diode) signs. This measure generated annual savings of $20000.
SETTING AN EXAMPLE
Other measures that generated substantial savings were transformer reconfiguration, halving transformer losses, which saved $15000/year, modification of the uninterruptible power system (UPS) generating a $13000 savings and, finally, load balance and power factor improvement. The installation of automatic power-factor improvement equipment in six medium voltage substations (4160V) improved the power factor from 88% to 94% after the implementation of this measure. This resulted in annual savings of $46000.
The recorded total kWh savings exceeded the targeted savings from the completed energy measures. This indicates that the overall post retrofit payback period is shorter and the internal rate of return is higher than expected.
It is hoped that the success of the energy-efficiency investment program at ADB will be seen by member countries as proof that efficiency and demand-side management are realistic policy options and can be successfully implemented in Asia. The ADB recently provided a tour of the building and briefing to a number of Filipino participants in a project development workshop for the Philippines Green Buildings Program. The existence of such a successful, high-profile retrofit has increased confidence among architects, engineers, designers, and building owners and managers in the Philippines that energy-efficiency retrofits in large commercial buildings can be a profitable venture.
Richard Templado Saing
Peter du Pont
Richard Templado Saing and Peter du Pont work with the International Institute for Energy Conservation (IIEC) rsaing@hotmail.com