The Harmonas-DEO system for monitoring and control of facilities at the Changi DCS Plant.

In the past Keppel DHCS had Azbil’s Harmonas-DEO™ central monitoring and control systems installed in all of its DCS plants in Singapore with the support by Azbil Singapore Pte. Ltd. On the background that these systems have contributed to consistent operations and also maintaining the quality of cooling water of these plants, Keppel DHCS requested Azbil Singapore anew for plans to bring about energy savings in line with the road map Keppel DHCS had drawn up.

Azbil Singapore, in response, presented plans using approaches to achieve energysaving effects by adopting new technologies that enable optimal control of heat source while using existing facilities, such as chillers, cooling towers, and pumps. The presentation also included an ESCO^*3 plan that guarantees energy-saving effects.

“In this scenario, we would not have to replace existing facilities with new ones, so we could hold down the initial investment. Moreover, Azbil would guarantee energy-saving effects for five years and a half thanks to the included ESCO plan. Therefore, the plan appeared to be very attractive to us in terms of minimizing risk. It sounded convincing for our parent company, Keppel Corporation, to give us an approval for the plan.” says Mr. Ng.

As a starter, Keppel DHCS implemented energy-saving measures to the Woodlands DCS plant, where upgrade of the existing facilities was kept to minimum by, for example, adding VSD (variable speed drive) units to them; and for the rest, a method of optimal control of all heat source facilities was adopted to improve the efficiency of their operations. Specifically, as an addition to the existing Harmonas-DEO system, a new utility optimization software package has been installed for optimal control of all heat source and utility facilities of the plant to meet the heat requirements of consumers and at the same time to minimize the overall electricity cost.

“At first we did not adopt for full automation of the plant operations in order to avoid risk. We were instructing operators to follow the guidance for optimal control of the facilities which is calculated by the optimization system, and there was always human intervention through the central monitoring and control system. However, as we were continuing to operate the plant with the optimization system, we have found the plant’s efficiency performance indicated by KPI^*4 has increasingly been improved, which we considered to be proof of appropriate operations at all times. After that, we transited to full automation based on utility optimization calculation without human intervention. The optimal control program continuously calculates values and supports plant operations nonstop throughout the year, so we have no worries about achieving energy savings,” says Mr. Zaw.

Chilled water for air conditioning in the Biopolis business district is supplied from Keppel’s DCS plant.

As a result of implementation of energy-saving measures, the Woodlands DCS plant has achieved a large reduction in electricity consumption by 2.28 mil. kW/year, much above its target of about 1.85 mil. kW/year. The achievement rate is 123 % of the target, which is high.

Since the efforts on the Woodlands DCS plant yielded very favorable results, similar measures have subsequently been implemented to the DCS at the Changi and Biopolis plants, which achieved a reduction of electricity consumption, again much above their targets, by over 8 mil. kW/year in total.

“In addition to the eager support by Azbil Singapore in operating the systems, Azbil Corporation remotely monitors our Harmonas-DEO unit and optimization results from Japan to provide support system maintenance and will log on to address problems in case of emergency, so we can feel great peace of mind. The azbil Group has a strong technological background, so we could implement the measures with a feeling of trust,” says Mr. Zaw.

“Azbil has helped to train our engineers as well. During the process of the project, our engineers’ awareness and skills have been improved through discussions with staff from Azbil Singapore and Azbil Corporation in Japan,” says Mr. Keng.

Keppel DHCS will make further efforts to take on energy savings in areas other than DCS plants.

“Our company is engaged in operating chilled water plants for buildings also. We are thinking about constructing a system that enables monitoring and control of multiple heat source control systems operated by different buildings from Keppel Corporation or a special control center. It is an important theme for us to achieve energy savings in this effort as well. From that standpoint also, I think the azbil Group is a very important partner for us to work together in realizing energy savings,” says Mr. Ng.