Supercooled PCM Condenser Control for Peak Cooling Demand

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Solution Overview

Problem

Existing air conditioning systems using phase change materials struggle to optimize thermal energy storage and efficiency, particularly in managing thermal energy during off-peak hours and varying ambient temperatures.

Innovation Solution

An air conditioning system incorporating a chiller system with a phase change material in thermal communication with the condenser, an actuator to transition the phase change material from a supercooled state to a solid state, and a controller to determine and initiate this transition based on ambient temperature profiles, utilizing supercooling to enhance thermal energy storage and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If phase change material is used to store thermal energy during off-peak hours, then thermal energy storage capacity is improved, but the system cannot release heat quickly enough during peak demand

Engineering Contradiction:
Improvethermal energy storage capacityVSAvoidheat release rate
Core Design Contradiction:
Quantity of substanceVSSpeed

Solution Approach 1:

The patent utilizes supercooling to change the thermal parameters of the phase change material. By cooling the PCM below its freezing point without it actually freezing, the system stores additional thermal energy. When triggered, the rapid phase transition from supercooled liquid to solid releases large amounts of heat quickly, resolving the contradiction between storage capacity and release rate.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention exploits the phase transition phenomenon of supercooling, where the phase change material remains in liquid state below its freezing point until triggered. This metastable state allows accumulation of thermal energy, and the subsequent rapid phase transition to solid state enables fast heat release during peak demand periods.

Inventive Principle:
Principle #36Phase transitions

2Use of energy by moving object

If phase change material is frozen during non-peak hours to store thermal energy, then energy efficiency is improved, but the system complexity increases due to additional control mechanisms

Engineering Contradiction:
Improveenergy efficiencyVSAvoidsystem complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The system allows the phase change material to supercool itself naturally during off-peak hours without active freezing mechanisms. The PCM autonomously reaches the supercooled state through passive cooling, and the trigger mechanism simply needs to initiate the phase transition rather than maintain continuous active control, reducing overall system complexity while improving energy efficiency.

Inventive Principle:
Principle #25Self-service

3Loss of energy

If ambient temperature is used to cool the phase change material, then energy costs are reduced, but the cooling effectiveness varies with weather conditions

Engineering Contradiction:
Improveenergy costVSAvoidcooling effectiveness
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The system performs preliminary cooling of the phase change material using ambient temperature during off-peak hours when ambient conditions are favorable. By preparing the PCM in a supercooled state in advance, the system ensures reliable operation during peak demand regardless of subsequent weather variations, combining low energy cost with improved reliability.

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

The system effectively utilizes supercooling to store thermal energy during off-peak hours, improving the efficiency and capacity of the air conditioning system by releasing heat quickly during peak demand, reducing energy costs, and optimizing heat exchanger design for faster heat transfer.

Implementation Method 1

determining whether an ambient temperature profile will result in supercooling of the phase change material

Methodology Applied
Scientific EffectSupercooling: Supercooling

Implementation Method 2

triggering the actuator to initiate changing the phase change material from a supercooled state to a solid state

Methodology Applied
Scientific EffectPhase change: Phase Change

Implementation Method 3

The phase change material is then used to absorb thermal energy during other modes of operation

Methodology Applied
Scientific EffectLatent heat: Latent Heat

Implementation Method 4

a phase change material in thermal communication with the condenser

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2844924B1Air conditioning system having supercooled phase change material
Publication Date: 2019.04.03 CARRIER CORP
  • EP2844924B1 patent drawingFigure 1
  • EP2844924B1 patent drawingFigure 2
  • EP2844924B1 patent drawingFigure 3

AI summary

An air conditioning system includes a chiller system including a compressor, a condenser, an expansion device and an evaporator; a phase change material in thermal communication with the condenser; an actuator coupled to the phase change material; and a controller providing a trigger signal to the actuator to initiate changing the phase change material from a supercooled state to a solid state.