Energy Supply Controller for Thermal Storage Cost and Temperature Control

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Solution Overview

Problem

Existing energy supply systems face challenges in maintaining continuous operation and reducing operational costs, particularly in underground thermal energy storage systems where temperature limits lead to suspended operations, increasing costs for classical heating/air conditioning equipment and requiring large, expensive systems.

Innovation Solution

Implementing a control method using dynamic programming to estimate and calculate operational costs, ensuring a predetermined energy supply, and optimizing temperature ranges for underground thermal energy storage systems, allowing for compact system design and efficient energy distribution between storage and production units.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the underground field temperature is allowed to reach limit values (12°C upper limit, 0°C lower limit) to maximize energy storage capacity, then the energy storage capacity is improved, but the system operation must be suspended when limits are reached, reducing reliability and increasing operational costs

Engineering Contradiction:
Improveenergy storage capacityVSAvoidcontinuous operation capability
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The controller performs preliminary actions by predicting future temperature developments based on current temperature profiles and energy demand patterns. Before the underground field reaches critical temperature limits, the controller proactively adjusts energy extraction/injection rates to prevent limit violations, ensuring continuous operation without suspension while maintaining maximum energy storage capacity

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements a feedback mechanism where the controller continuously monitors the actual temperature profile of the underground field, compares it with predicted profiles, and adjusts operating parameters in real-time. This closed-loop control ensures the field operates near temperature limits without exceeding them, maintaining both maximum energy storage capacity and continuous operation reliability

Inventive Principle:
Principle #23Feedback

2Reliability

If the classical heating/air conditioning equipment is designed to supply the whole amount of thermal energy demand to ensure continuous operation, then the reliability is improved, but the system size and cost increase significantly

Engineering Contradiction:
Improvecontinuous operation capabilityVSAvoidsystem size and cost
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system transitions from a static design where classical equipment must handle peak loads to a dynamic system where the underground field's temperature profile is continuously optimized. The controller dynamically adjusts energy flows between the underground field and classical equipment, allowing the field to supply variable amounts of thermal energy based on real-time temperature conditions, thereby reducing the required capacity of classical equipment while maintaining continuous operation

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The controller changes operating parameters by adjusting the temperature profile of the underground field within acceptable ranges. By optimizing temperature parameters and energy flow rates in real-time, the system maximizes the contribution of the underground field to thermal energy demand, reducing the size and cost of classical heating/air conditioning equipment while ensuring continuous reliable operation

Inventive Principle:
Principle #35Parameter changes

3Use of energy by moving object

If the underground field temperature drops below 0°C or rises above 12°C to maximize seasonal energy shifting, then the energy storage efficiency is improved, but the operational cost increases when classical equipment must supply full thermal energy

Engineering Contradiction:
Improveenergy storage efficiencyVSAvoidoperational cost
Core Design Contradiction:
Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The controller uses feedback from temperature sensors to continuously monitor the underground field temperature and adjusts energy extraction/injection rates to maintain temperatures within the optimal range (above 0°C and below 12°C). This prevents the field from reaching temperatures where operation would need to be suspended, avoiding the high operational costs of classical equipment while maintaining high energy storage efficiency

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs preliminary actions by predicting temperature trends based on current conditions and future energy demands. Before temperatures approach critical thresholds, the controller proactively adjusts operating parameters to maintain efficient temperature ranges, preventing costly operational suspensions and reducing overall operational costs while maximizing energy storage efficiency

Inventive Principle:
Principle #10Preliminary action

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

Guarantees continuous energy supply within predetermined temperature ranges, reduces operational costs by optimizing energy distribution between classical heating/air conditioning and heat pumps, and enables the design of more compact energy supply systems.

Implementation Method 1

In winter, a heat pump may extract heat from the field and warm it up to approximately 40°C at low energy costs and high energy efficiency

Methodology Applied
Scientific EffectHeat pump: Heat Exchanger

Implementation Method 2

Underground thermal energy storage systems (UTESS), which comprise a large underground volume that may store a huge amount of thermal energy

Methodology Applied
Scientific EffectThermal energy storage: Thermal Energy Storage

Implementation Method 3

Each borehole may comprise a loop circuit for a liquid, which acts as carrier of thermal energy (e.g. water)

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2321583B1Controller for energy supply systems
Publication Date: 2019.01.02 VLAAMSE INSTELLING VOOR TECHNOLOGISCH ONDERZOEK NV (VITO)
  • EP2321583B1 patent drawingFigure 1
  • EP2321583B1 patent drawingFigure 2~3
  • EP2321583B1 patent drawingFigure 4

AI summary

The present invention relates to energy supply systems which comprise an energy storage unit and an energy production unit. Control methods according to the invention advantageously allow to calculate an operational cost of the energy supply system based on the energy flux that can be supplied by the system and the energy flux that is demanded externally from the system. The operational cost can be calculated for all possible values of the above parameters in advance. The calculated parameters can be stored in an array in a device implementing methods of the invention. Methods of the invention allow to operate an energy supply system so as to guarantee that at any instant a predetermined (nonzero) amount of energy flux can be supplied by the energy storage unit.