Transportation refrigeration unit with external AC generator power source
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Solution Overview
Problem
Current transportation refrigeration units face challenges in efficiency, environmental impact, reliability, cost, and weight reduction, particularly in their power systems which often rely on diesel engines and lack efficient energy management.
Innovation Solution
A transportation refrigeration unit (TRU) system powered by an external generator system via a generator power converter, utilizing a power management system to direct power based on AC power requirements, incorporating an energy storage system, and a grid power connection to optimize energy use and reduce fuel consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a diesel engine is used to power the refrigeration unit, then the unit can operate independently, but fuel carriage weight and emissions increase
Solution Approach 1:
The patent extracts the diesel engine from the refrigeration unit system, separating the propulsion function from the refrigeration function. The refrigeration unit is powered externally by the vehicle's engine through a PTO or electrical connection, eliminating the need for onboard fuel storage and diesel-powered compressor while maintaining operational reliability
Solution Approach 2:
The patent makes the refrigeration system compatible with multiple power sources including diesel engine PTO, electrical power from vehicle alternator, and external power supplies. This multi-functionality allows the same refrigeration unit to operate in various configurations without requiring dedicated fuel storage
2Reliability
If a diesel engine is used to power the refrigeration unit, then the unit can operate independently, but environmental impact worsens
Solution Approach 1:
The patent removes the diesel engine and associated emissions from the refrigeration unit by using external power sources. The compressor can be powered electrically from the vehicle's alternator or PTO, eliminating exhaust emissions from the refrigeration system while maintaining operational independence
Solution Approach 2:
The patent replaces the mechanical diesel engine-compressor system with an electrically-driven compressor system. The compressor motor is powered by electrical energy from the vehicle's powertrain, substituting mechanical combustion with electrical actuation to reduce harmful emissions
3Device complexity
If traditional power systems are used, then the system is simple, but efficiency and energy management are poor
Solution Approach 1:
The patent implements a dynamic power management system that continuously monitors vehicle operating conditions, refrigeration load requirements, and energy availability. The system dynamically adjusts compressor operation, thermal energy storage charging/discharging, and power source selection to optimize energy efficiency based on real-time conditions
Solution Approach 2:
The patent uses thermal energy storage systems that pre-cool or pre-heat thermal mass during periods of excess energy availability, such as when the vehicle engine is running and excess electrical power is available. This preliminary action reduces peak power demands and improves overall energy efficiency by shifting load timing
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 solution enhances the efficiency and environmental sustainability of refrigeration units by reducing fuel carriage and emissions, improving reliability through efficient energy management, and minimizing noise pollution, while conveniently recharging energy storage devices to meet power demands.
Implementation Method 1
an alternating current (AC) generator operably coupled to an axle or wheel hub, and configured to provide three phase AC power to the power management system
Implementation Method 2
an evaporator heat exchanger operatively coupled to the compressor, an evaporator fan configured to provide return airflow from a return air intake and flow the return airflow over the evaporator heat exchanger
Implementation Method 3
a compressor configured to compress a refrigerant
Data Source
AI summary
A transportation refrigeration unit TRU (26) and power system. The TRU (26) and power system including a compressor (58) configured to compress a refrigerant, an evaporator heat exchanger (76) operatively coupled to the compressor (58), and an evaporator fan (98) configured to provide return airflow (134) and flow the return airflow (137) over the evaporator heat exchanger (76). The system also includes a return air temperature RAT sensor (142) disposed in the return airflow (134) and configured to measure the temperature of the return airflow (134), a TRU controller (82) operably connected to the RAT sensor (142) and configured to execute a process to determine an AC power requirement for the TRU (26) based on at least the RAT sensor (142); an alternating current AC generator (162) operably coupled to an axle or wheel hub, and configured to provide a first three phase AC power (163) to a power management system (124), the power management system (124) configured to direct power the TRU (26) based on the AC power requirement.