Cooling Plant Thermal Storage Scheduling Optimization

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Solution Overview

Problem

Existing cooling systems face challenges in efficiently managing time-varying cooling demands and underutilization of thermal ice storage systems due to conservative scheduling methods and oversimplification of chiller operation modes, leading to increased costs and reliability concerns.

Innovation Solution

A cooling plant system incorporating thermal and electrical energy storage systems, coupled with an energy storage and scheduling control system that optimizes operations through a scheduling module, providing selective electrical energy to thermal energy storage systems and enabling frequency regulation and contingency reserve services.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple resources are used to meet cooling demand, then reliability is improved, but operating cost increases

Engineering Contradiction:
Improvecooling system reliabilityVSAvoidoperating cost
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system pre-charges thermal energy storage systems during low-demand periods when electricity prices are lower, storing cooling capacity in advance. This preliminary action allows the system to meet peak cooling demands using stored energy rather than activating additional resources, thereby maintaining reliability while reducing operating costs during high-demand periods.

Inventive Principle:
Principle #10Preliminary action

2Use of energy by moving object

If thermal ice storage systems are used to assist chillers, then economic viability is improved, but system complexity increases

Engineering Contradiction:
Improveeconomic viabilityVSAvoidsystem complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The system merges thermal energy storage systems with the existing chiller infrastructure into an integrated cooling plant. The control system coordinates operation between chillers and thermal storage, allowing them to work as a unified system rather than separate components. This combination achieves economic benefits through optimized resource utilization while managing complexity through integrated control architecture.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The thermal energy storage systems serve multiple functions: they provide auxiliary cooling capacity during peak periods, store energy for economic operation during low-price periods, and can be charged using waste heat from chiller operations. This multi-functionality justifies the added complexity by delivering multiple benefits from a single system component.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If conservative scheduling algorithms are used for thermal ice storage systems, then reliability is improved, but underutilisation occurs

Engineering Contradiction:
Improvesystem reliabilityVSAvoidthermal storage utilisation
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The control system implements feedback mechanisms that continuously monitor cooling demand patterns, thermal storage state of charge, and electricity pricing signals. Based on this real-time feedback, the system dynamically adjusts charging and discharging schedules, enabling more aggressive and optimized utilization of thermal storage while maintaining reliability constraints. This feedback-driven approach replaces conservative static scheduling with adaptive dynamic scheduling.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system transitions from static, conservative scheduling algorithms to dynamic scheduling that adapts to real-time conditions. The control strategy continuously optimizes thermal storage utilization based on varying cooling demands, electricity prices, and system state, allowing the system to exploit storage capacity more fully while maintaining reliability through real-time adjustments rather than fixed conservative rules.

Inventive Principle:
Principle #15Dynamics

4Device complexity

If chiller scheduling assumes only two working modes, then device complexity is reduced, but productivity is limited

Engineering Contradiction:
Improvescheduling complexityVSAvoidcooling output flexibility
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The chiller operation is segmented into multiple discrete modes (e.g., full cooling, partial cooling, heating-only, idle) rather than treating it as a continuous two-state system. This segmentation allows the control system to select from a richer set of operational states, improving productivity and flexibility in meeting varying cooling demands while maintaining manageable scheduling complexity through discrete mode transitions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system changes the operational parameters of chillers beyond simple on/off states, including variable cooling capacity levels, variable heating capacity levels, and different operational modes (cooling vs. heating). These parameter changes enable more flexible and productive chiller operation while the control system manages the increased complexity through structured parameter management and mode-based control strategies.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The system enhances economic viability and reliability by optimizing energy usage, reducing operational costs, and effectively managing peak demands through advanced scheduling and energy storage strategies.

Implementation Method 1

one or more thermal energy storage systems coupled to the one or more cooling towers

Methodology Applied
Scientific EffectThermal energy storage: Thermal Energy Storage

Implementation Method 2

thermal ice storage systems (ISSs; a type of thermal storage system)

Methodology Applied
Scientific EffectPhase change: Phase Change

Implementation Method 3

one or more electrical energy storage systems, the one or more electrical energy storage systems being coupled to the one or more thermal energy storage systems for selectively providing electrical energy

Methodology Applied
Scientific EffectElectrical energy storage: Electrical Accumulator

Data Source

PatentUS11898803B2Cooling plant system and method of operating said system
Publication Date: 2024.02.13 SINGAPORE DISTRICT COOLING PTE LTD
  • US11898803B2 patent drawing
  • US11898803B2 patent drawing
  • US11898803B2 patent drawing

AI summary

The present disclosure may provide a cooling plant system, a method of operating a cooling plant system and an energy storage and scheduling control system, the cooling plant system comprising one or more cooling towers; one or more thermal energy storage systems coupled to the one or more cooling towers; one or more electrical energy storage systems, the one or more electrical energy storage systems being coupled to the one or more thermal energy storage systems for selectively providing electrical energy to the one or more thermal energy storage systems; and an energy storage and scheduling control system coupled to the one or more thermal energy storage systems and the one or more electrical energy storage systems.