Trailer Refrigeration Inverter Heating Using Engine Waste Heat

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Solution Overview

Problem

Conventional refrigeration systems face high costs due to the need for preheating inverter circuits when operating at temperatures lower than their operational range, requiring additional heating systems which increase manufacturing costs.

Innovation Solution

The system utilizes waste heat from the engine to heat the inverter circuit, either directly or through a heat radiator, with a temperature sensor controlling the heating mechanism to maintain operational temperatures without additional heating systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If an inverter circuit is selected for operational temperature of -30°C or lower to enable operation at low temperatures, then the refrigeration system can operate at lower temperatures, but the cost of the inverter circuit increases significantly

Engineering Contradiction:
Improveoperating temperature rangeVSAvoidinverter circuit cost
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The invention converts the harmful waste heat from the engine into a beneficial heating source for the inverter circuit. By utilizing the engine's waste heat through a heat exchange mechanism, the system can operate the inverter circuit at acceptable temperatures without requiring an expensive low-temperature rated inverter circuit, thus resolving the cost issue while maintaining low-temperature operational capability

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The invention introduces a heat exchange mechanism as an intermediary between the engine and the inverter circuit. This intermediary transfers thermal energy from the engine's waste heat to the inverter circuit, enabling temperature control without direct thermal contact and without requiring a separate heating system or expensive low-temperature components

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a separate preheating system is added to heat the inverter circuit when operating at low temperatures, then the inverter circuit can operate at acceptable temperatures, but the manufacturing cost of the refrigeration system increases

Engineering Contradiction:
Improveinverter circuit operabilityVSAvoidsystem manufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention makes the engine serve multiple functions: it not only drives the refrigeration system but also provides waste heat that can be utilized for heating the inverter circuit. This multi-functionality eliminates the need for a separate preheating system, reducing manufacturing costs while ensuring reliable inverter circuit operation at low temperatures

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

Solution Approach 2:

The invention recovers waste heat from the engine that would otherwise be discarded. By capturing and utilizing this waste heat for heating the inverter circuit, the system eliminates the need for a separate preheating system, reducing manufacturing costs while maintaining reliable operation

Inventive Principle:
Principle #34Discarding and recovering

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 allows the inverter circuit to operate at lower temperatures without a separate heating system, thereby reducing manufacturing costs and maintaining operational efficiency.

Implementation Method 1

The heating mechanism (60) heats the inverter circuit (71) with waste heat of the engine (41)

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

The temperature sensor (74) senses a temperature of the inverter circuit (71)

Methodology Applied
Scientific EffectTemperature sensing: Thermocouple

Data Source

PatentEP2442053B1Refrigeration device for transportation
Publication Date: 2019.01.30 DAIKIN INDUSTRIES LTD
  • EP2442053B1 patent drawingFigure 1
  • EP2442053B1 patent drawingFigure 2
  • EP2442053B1 patent drawingFigure 3

AI summary

A refrigeration system for trailer includes an engine (41), a generator (40) driven by the engine (41) to generate electric power, an inverter substrate, a temperature sensor (74) that senses a temperature of the inverter circuit, and a heat carrying mechanism (60) that heats the inverter substrate with waste heat of the engine (41) when a sensed temperature by the temperature sensor (74) is an operational temperature or lower.