Transport Refrigeration Battery-Grid Control for Low-Noise Cooling

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Solution Overview

Problem

Transport refrigeration units (TRUs) face challenges in reducing noise and emissions, as traditional diesel engines are inefficient and environmentally harmful, necessitating a quieter and cleaner power source.

Innovation Solution

Implementing a non-diesel energy storage device (ESD) with a controller that communicates with the TRU to manage energy needs, using solar panels for power generation, and integrating with the electrical grid for smart grid optimization, allowing battery pack capacity to be controlled based on loading schedules and ambient conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a diesel engine is used as the TRU power source, then sufficient power is available for refrigeration operation, but noise levels are high and emissions are harmful

Engineering Contradiction:
Improvenoise and emissionsVSAvoidpower source capability
Core Design Contradiction:
Object-affected harmful factorsVSPower

Solution Approach 1:

The patent replaces the traditional diesel engine (mechanical combustion system) with an electrical power source consisting of a battery pack and motor generator assembly. This substitution eliminates the combustion process that generates noise and harmful emissions, while providing sufficient electrical power to drive the refrigeration compressor and other TRU components through an inverter system.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental operating parameters of the TRU by transitioning from a thermal engine (diesel) to an electrical system. The battery pack provides variable voltage and current output that can be precisely controlled to match the refrigeration load requirements, enabling quiet and emission-free operation across different operating conditions.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If a non-diesel energy storage device is used to reduce noise and emissions, then cleaner operation is achieved, but energy management complexity increases

Engineering Contradiction:
Improveemissions and noiseVSAvoidenergy management system
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent integrates multiple functions into the motor generator assembly, which serves both as a motor to drive the compressor during refrigeration operation and as a generator to recharge the battery pack during peak production periods or when excess electrical power is available. This multi-functionality reduces the need for separate components and simplifies the overall energy management architecture.

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

Solution Approach 2:

The control system continuously monitors battery state of charge, refrigeration load requirements, and grid electricity rates to dynamically adjust power distribution. This feedback mechanism enables the system to automatically optimize between drawing power from the grid, using battery storage, and recharging during peak production, thereby managing complexity through intelligent control rather than mechanical complexity.

Inventive Principle:
Principle #23Feedback

3Productivity

If battery pack capacity is made available to the electrical grid for smart grid optimization, then economic rebates and utility incentives are achieved, but TRU energy availability may be compromised

Engineering Contradiction:
Improveeconomic benefit from grid integrationVSAvoidTRU energy availability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system charges the battery pack during off-peak hours or during peak production periods when the container is not actively being cooled, preparing energy storage in advance of when it will be needed for refrigeration operation. This preliminary charging action ensures that sufficient energy is available in the battery to maintain refrigeration temperatures even when the container is disconnected from the grid or during high-demand periods.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The control system dynamically adjusts the balance between grid power import, battery charging, and refrigeration load based on real-time conditions including battery state of charge, ambient temperature, container load, and utility pricing signals. This dynamic management ensures that economic opportunities from grid integration are captured while maintaining sufficient energy availability to meet refrigeration requirements at all times.

Inventive Principle:
Principle #15Dynamics

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 solution results in quieter and cleaner TRU operation, enabling efficient energy management and smart grid integration, while allowing for economic rebates and utility incentives through optimized energy use and peak production.

Implementation Method 1

Each TRU may further include a solar panel operably coupled to at least the corresponding TRU battery pack

Methodology Applied
Scientific EffectSolar energy conversion: Photovoltaic Effect

Data Source

PatentEP3635836B1Transport refrigeration unit architecture and controls for smart grid optimization and integration
Publication Date: 2024.11.06 CARRIER CORP
  • EP3635836B1 patent drawingFigure 1~2
  • EP3635836B1 patent drawingFigure 3~4
  • EP3635836B1 patent drawingFigure 5~7

AI summary

A transport refrigeration unit (TRU) system(lO) is provided. The TRU system includes a TRU (30), an electrical grid and a control unit. The TRU (30) is configured to be operably coupled a container (20) and includes components configured to control an environment within an interior of the container (20) and a TRU battery pack (40) configured to store energy for powering at least the components. The control unit is communicative with the TRU (30) and the electrical grid and is configured to manage power supplies and demands between the TRU battery pack (40) of each TRU (30) and the electrical grid.