Central Plant Optimization for Waste Energy Reduction

EW-201349

Objective

The Department of Defense (DoD) spent close to $4 billion in 2010 on energy costs for its facilities. Many of DoD’s fixed installations receive usable energy in the form of electric power, heating, and cooling via central plants. Central plants are currently operated to meet all demands reliably, not necessarily for fuel economy or energy efficiency. Central plants contain multiple chiller, boiler, power generation, and auxiliary equipment. Individual equipment operates on different efficiency curves that vary with part load, ambient conditions, and other operating parameters. In addition, the site receives real-time price signals for electricity and need to consider fluctuating fuel prices and other costs. From a systems operations perspective, an operator would be faced with huge sets of decision alternatives in order to allocate load efficiently and to operate the equipment at the most efficient and cost-effective set points.

Honeywell will implement an advanced, system-level, dynamic optimization of central plant and distribution system for operational energy and cost savings. The demonstration objective is to measure the energy savings impact of real-time optimization of a large DoD central plant. Central plants at Fort Bragg, North Carolina are being considered for the demonstration.

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Technology Description

The fundamental problem to be addressed is the transformation of central plant operation to an automated, dynamically optimized operation that minimizes energy consumption and cost. Central Plant Optimization for Waste Energy Reduction (CPOWER) will leverage Honeywell’s industry-leading expertise in control and optimization. Honeywell has developed a suite of optimization and control technologies specially targeting the supply, distribution, and demand of energy. The team will employ a model-predictive run-time optimization technology for CPOWER that views the generation, storage, and distribution of cooling and heating energy collectively while maintaining building comfort. Innovative features include: 1) economic dispatch of major equipment combined with optimum operating setpoints (temperatures and flows); 2) model-predictive dynamic optimization for optimality in the time dimension; 3) self-adaptive models of plant, building, and load forecast; and 4) integration of building comfort feedback. Based on the inputs of upcoming loads, price signals, central plant performance models, and building response, a mixed-integer evolutionary optimizer algorithm solves the schedules and setpoints for the major equipment in the central plant. The optimization solution will be integrated with the plant control system and operate continuously in a supervisory capacity.

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Benefits

CPOWER will enable electricity and gas savings from: 1) starting and stopping schedules of plant equipment for efficiency, forecasted loads, and real-time price signals; 2) operating equipment at part loads, temperature, and flow setpoints that maximize system efficiency; and 3) changing pump and fan speeds in response to optimum flow rates. Cost savings will come from considering real-time price signals for electricity and from reduction in energy use. Electricity and gas savings in prototypes of the optimization for chiller plants have ranged from 20% to greater than 40%. A life-cycle cost (LCC) analysis was conducted based on the electricity and gas costs at the Fort Bragg cooling and heating plants and predicted 30% energy savings. Simple payback is achieved in less than two years and a savings-to-investment ratio of 9.5 is achieved over a 20-year period. Facility managers can also increase equipment life and reduce maintenance costs based on the equipment performance models that are continuously updated from operational data. Other benefits include reduced greenhouse gas emissions and contribution toward energy security and net-zero energy goals. (Anticipated Project Completion - 2015)

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Points of Contact

Principal Investigator

Dr. Girija Parthasarathy

Honeywell International, Inc.

Phone: 763-954-6554

Fax: 763-954-5489

Program Manager

Energy and Water

SERDP and ESTCP

Document Types

  • Project Overview - Brief project summary with links to related documents and points of contact.
  • Final Report - Comprehensive report for every completed SERDP and ESTCP project that contains all technical results.
  • Cost & Performance Report - Overview of ESTCP demonstration activities, results, and conclusions, standardized to facilitate implementation decisions.
  • Technical Report - Additional interim reports, laboratory reports, demonstration reports, and technology survey reports.
  • Guidance - Instructional information on technical topics such as protocols and user’s guides.
  • Workshop Report - Summary of workshop discussion and findings.
  • Multimedia - On demand videos, animations, and webcasts highlighting featured initiatives or technologies.
  • Model/Software - Computer programs and applications available for download.
  • Database - Digitally organized collection of data available to search and access.