Thermal Storage Unit for Power Grid Energy Management

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Solution Overview

Problem

Existing methods for managing overcapacities in power networks are inefficient due to inadequate steam quality and quantity for steam turbines, reliance on a single medium (steam) for power generation, and high system complexity and costs.

Innovation Solution

A thermal storage unit and heat exchanger system that stores energy from the power network and utilizes it to preheat air, fuel, or combustion gases in a gas turbine system, or for steam superheating in a steam turbine system, reducing fuel consumption and increasing efficiency by integrating with both gas and steam turbine systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If thermal storage unit generates steam directly for steam turbine, then electrical energy can be stored and retrieved, but the quality and quantity of steam generated are inadequate for operating steam turbine efficiently

Engineering Contradiction:

Improveenergy storage efficiencyVSAvoidsteam quality for turbine operation

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

A heat exchanger is introduced as an intermediary between the thermal storage unit and the steam turbine system. The heat exchanger transfers thermal energy from the storage unit to the water/steam circuit, enabling proper steam generation without directly heating water in the turbine system. This mediator resolves the contradiction by decoupling the storage function from the steam generation function.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system is divided into separate functional modules: thermal storage unit, heat exchanger, and steam turbine system. The thermal storage unit handles energy storage independently, while the heat exchanger manages heat transfer, and the steam turbine system handles power generation. This segmentation allows each component to optimize its function without compromising overall system performance.

Inventive Principle:

Principle #1Segmentation

2Stability of the object's composition

If conventional power plants increase capacity to compensate for renewable energy fluctuations, then power supply stability improves, but system complexity and costs increase

Engineering Contradiction:

Improvepower supply stabilityVSAvoidsystem complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The thermal storage unit enables the renewable energy system to serve itself by storing excess energy during overcapacity periods and releasing it during deficits. This self-service capability eliminates the need for additional conventional power plant capacity, maintaining stability without increasing system complexity.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

Energy is stored in advance during periods of overcapacity before it is needed. The thermal storage unit pre-charges thermal energy when renewable generation exceeds demand, making energy available later without requiring reactive capacity increases or complex control systems.

Inventive Principle:

Principle #10Preliminary action

3Ease of manufacture

If thermal storage unit is used only for steam generation, then system design is simplified, but adaptability to different heat consumers is limited

Engineering Contradiction:

Improvesystem design simplicityVSAvoidheat consumer flexibility

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The heat exchanger is designed with multiple connections to different heat consumers including steam turbines, gas turbines, and other thermal users. This multi-functional design allows the same thermal storage system to serve various purposes - power generation, process heating, and industrial applications - without requiring separate systems for each application.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

This approach enhances the overall efficiency of gas turbine systems, reduces fuel consumption, and allows for flexible energy utilization across multiple heat consumers, minimizing conversion losses and eliminating the need for high-quality steam diversion.

Implementation Method 1

a heating element (8) for storing energy from the power network (9) in the thermal storage unit (10)

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 2

a heat exchanger (11) having a primary side and a secondary side, the primary side being coupled thermally to the thermal storage unit (10) for extracting heat from the thermal storage unit (10) and the secondary side being connected to a power plant system (12)

Methodology Applied

Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 3

The heat is used as required in the thermal storage unit to generate steam

Methodology Applied

Scientific EffectPhase change: Phase Change

Data Source

PatentUS8938966B2Storage of electrical energy with thermal storage and return through a thermodynamic cycle

Publication Date: 2015.01.27 SIEMENS ENERGY GLOBAL GMBH & CO KG

AI summary

A device and a method for using overcapacities in the power grid is provided. In case of an oversupply of energy, the energy is transferred to a thermal storage device directly via a heating element and in the discharge case of the thermal storage device the heat is removed from the thermal storage device and made available to a thermodynamic cycle whereby electrical energy is produced. The heat from the thermal storage device is used to preheat air in an air feed line to a combustion chamber, or fuel is pre-heated using heat from the thermal storage device.