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Narita International Airport Central Heating and Cooling Plant

Cost Minimized by Guidance for Optimized Starting and Stopping of Individual Heat Source Units

A substantial portion of the passenger terminals at the airport is covered with glass, and therefore the heating load or cooling load needed for heating or air conditioning depends on the weather. The main goal of the utility optimization software package is to calculate the demand for chilled and/or hot water for air conditioning and heating based on external weather forecast services. The utility optimization software package predicts the energy needs in half-hour periods for up to 24 hours based on the latest weather information, which is updated every 60 minutes, and provides operators with guidance on which heat source equipment in the central heating and cooling plant to select—for example, whether to use an electric or a gas unit—and when to start or stop the equipment. Taking into consideration the unit cost of energy, which changes every month, it supports heat supply operation by a best mix of equipment, electricity and gas, to minimize the cost at each moment.

“In the past, operators started or stopped the heat equipment at their discretion, based on the weather that day or the temperature on the previous day. But after installing the utility optimization software package, we were able to start or stop the equipment on a more optimal and detailed timeline. For example, we previously started the equipment with a margin of 1 hour, but the software guidance shortened that to 30 minutes. Small amounts of cost savings can lead to a big result,” says Mr. Yamamoto.

Additionally, according to Eiichi Shimada, a chief engineer for the Mechanical Systems Department, “Since the start of operations, we have shared with Azbil the advice given by the utility optimization software package, along with the actual operational status of the site’s facilities. Based on that information, Azbil has tuned the system and increased the accuracy of the advice.”

Final decisions on starting or stopping the plant equipment are made by a frontline operator. Through the past 3 years of system operation, onsite know-how accumulated by the operators, combined with the knowledge that Azbil has incorporated into the utility optimization software package, has taken the cost-efficient operation of the system to a higher level.

The target preset for energy cost reduction was achieved in the very first fiscal year. Furthermore, an unexpected level of improvement, 140% of the target, was reached in the 2nd and the 3rd fiscal years, which was the equivalent of about a 700 ton reduction of CO2 emissions per year. The energy-saving project helped the environment as well as producing savings.

“At trimonthly meetings, Azbil reports to us in an easy-to-understand way about the results from the utility optimization software package. Additionally, we appreciate Azbil’s support in resolving problems that occur on the site, and its positive efforts to provide us with information and know-how on energy-efficiency in general,” comments Masato Hagiwara of the Facilities Management Department. “We would also like Azbil to deliver not only help with further energy cost reduction, but also proposals for energy-saving measures from a broader perspective, beyond the framework of the measures taken this time,” says Mr. Kondo.

An electric chiller in the central heating and cooling plant.

An electric chiller in the central heating and cooling plant.

A two-drum water tube steam boiler.

A two-drum water tube steam boiler.

glossary

*1 DCS (Distributed Control System)
A system that monitors and controls the manufacturing process or production facilities in plants and factories. To achieve even distribution of load, the DCS distributes the functions of each device over a network, resulting in safety and excellent maintainability.
*2 ESCO (Energy Service COmpany) project
A project in which an energy service company guarantees a certain level of energy savings through the provision of comprehensive services for the reduction of energy consumption in a factory or building. There are two types of contract.
Guaranteed-savings contract: The facility owner bears the project costs and the energy service company guarantees the energy savings.
Shared-savings contract: The energy service company bears the project costs and the customer pays a fee for the energy savings and other services.

These case studies were published in the 2018 Vol.3 issue of the azbil Group's corporate magazine, azbil.