Transport Refrigeration DC-to-AC Variable Inverter for Fuel Efficiency

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Solution Overview

Problem

Existing transport refrigeration systems in refrigerated vehicles and trailers require inefficient power management, leading to high fuel usage due to the need for continuous power to the compressor and fans, which is not optimized for varying conditions or energy storage.

Innovation Solution

A transport refrigeration system incorporating a DC-to-AC variable inverter and a power management module that stores DC electrical energy and converts it to AC, allowing for a variable continuous energy output to power the refrigeration unit, adjusting based on refrigeration unit and energy storage device parameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a prime mover continuously powers the compressor and fans in a transport refrigeration system, then the refrigeration function is maintained, but fuel consumption increases

Engineering Contradiction:
Improverefrigeration function maintenanceVSAvoidfuel consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system dynamically adjusts the operation of the compressor and fans based on real-time temperature sensor feedback. When the cargo space temperature is within the desired range, these components are turned off or reduced to low power mode, eliminating continuous operation and reducing fuel consumption while maintaining refrigeration reliability when needed

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

Temperature sensors continuously monitor the cargo space temperature and provide feedback to the control system. This feedback loop enables the system to make real-time decisions about when to activate or deactivate the compressor and fans, optimizing fuel usage while ensuring the refrigeration function is maintained only when necessary

Inventive Principle:
Principle #23Feedback

2Use of energy by moving object

If a DC-to-AC variable inverter is used to convert DC electrical energy to AC with variable continuous energy output, then energy use efficiency is improved, but device complexity increases

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

Solution Approach 1:

The DC-to-AC variable inverter serves multiple functions: it converts DC electrical energy from the energy storage device to AC power for the refrigeration unit, and it provides variable continuous energy output control to optimize efficiency. This multi-functionality justifies the added complexity by delivering significant energy efficiency improvements

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

Solution Approach 2:

The inverter enables dynamic adjustment of electrical parameters (voltage, frequency, power output) to match the actual cooling demands of the cargo space. By changing these parameters based on real-time conditions, the system achieves superior energy efficiency compared to fixed-output systems, warranting the increased device complexity

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

This solution improves the efficiency of the refrigeration system by optimizing energy use and reducing fuel consumption, enhancing the ability to maintain controlled temperature environments for perishable goods during transport.

Implementation Method 1

a DC-to-AC variable invertor electrically connecting the energy storage device to the transportation refrigeration unit, the DC-to-AC variable invertor being configured to convert the DC electrical energy from the energy storage device to AC electrical energy in a variable continuous energy output

Methodology Applied
Scientific EffectElectrical energy conversion (DC to AC):

Implementation Method 2

Air or an air/ gas mixture is drawn from the interior volume of the cargo space by means of the evaporator fan(s) associated with the evaporator, passed through the airside of the evaporator in heat exchange relationship with refrigerant whereby the refrigerant absorbs heat from the air, thereby cooling the air

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP3750725B1Transport refrigeration system and method of operating it
Publication Date: 2024.07.24 CARRIER CORP
  • EP3750725B1 patent drawingFigure 1
  • EP3750725B1 patent drawingFigure 2
  • EP3750725B1 patent drawingFigure 3

AI summary

A transport refrigeration system (200) including: a transportation refrigeration unit (22) configured to provide conditioned air to a refrigerated cargo space (119); an energy storage device (350) configured to store DC electrical energy to power the transportation refrigeration unit (22); and a DC-to-AC variable invertor (370) electrically connecting the energy storage device (350) to the transportation refrigeration unit (22), the DC-to-AC variable invertor (370) being configured to convert the DC electrical energy from the energy storage device (350) to AC electrical energy in a variable continuous energy output to power the transportation refrigeration unit (22).