Sensor mount for a mobile refrigeration system
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Solution Overview
Problem
The existing mobile heat exchange systems for refrigeration in vehicles and trailers face inefficiencies due to temperature differentials caused by thermal energy radiation and conduction from the generator, leading to inaccurate temperature readings by the return air temperature sensor, resulting in increased on/off cycles and prolonged operation of the refrigeration unit, which increases costs.
Innovation Solution
A refrigeration system with a shock absorption unit that mounts the sensor to provide a limited thermal conduction path and thermally isolates it from the power package, ensuring accurate temperature measurements by reducing the impact of thermal energy radiation and conduction, and a method to regulate environmental conditions based on these measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensor is mounted directly to the air duct panel, then the sensor is securely positioned, but thermal energy from the generator is conducted to the sensor causing inaccurate temperature readings
Solution Approach 1:
A thermal barrier material is positioned between the sensor and the air duct panel to block thermal conduction from the generator while still allowing the sensor to accurately measure air temperature. This intermediary layer prevents harmful thermal energy transfer while maintaining sensor functionality.
Solution Approach 2:
The sensor is extracted from direct thermal contact with the air duct panel by mounting it on a stem or support structure that extends into the air duct. This separates the sensor from the thermal influence of the panel while keeping it positioned to measure air temperature accurately.
2Reliability
If the refrigeration unit operates longer to compensate for temperature differential, then temperature control reliability improves, but energy consumption increases
Solution Approach 1:
The controller continuously monitors the sensor output signal and adjusts the refrigeration unit operation accordingly. By using accurate temperature feedback from the thermally-isolated sensor, the controller can make precise on/off decisions without unnecessary extended operation, reducing energy consumption while maintaining temperature control reliability.
3Ease of operation
If the sensor is positioned in the return air duct proximate the evaporator, then it can measure air temperature for control, but it is exposed to thermal radiation from the generator causing measurement errors
Solution Approach 1:
A thermal barrier or shield is positioned between the sensor and the generator to block thermal radiation while allowing the sensor to remain in the return air duct for accurate temperature monitoring. This intermediary structure prevents radiant heat transfer from the generator to the sensor.
Solution Approach 2:
The air duct structure is designed with localized thermal insulation or reflective barriers at specific positions where thermal radiation from the generator would affect the sensor. This creates zones of thermal protection while maintaining overall air flow and temperature monitoring functionality.
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 enhances the accuracy of temperature readings, reduces unnecessary on/off cycles, and improves energy efficiency by minimizing the impact of thermal energy on the sensor, thus optimizing the operation of the refrigeration system.
Implementation Method 1
The shock absorption unit mounts the sensor to and provides a limited thermal conduction path between the sensor and the first panel
Implementation Method 2
the sensor from thermal energy radiated and conducted from the power package
Implementation Method 3
The air duct directs air from an air inlet to the evaporator
Implementation Method 4
The refrigeration loop includes a compressor, a condenser, a refrigerant regulator and an evaporator
Data Source
AI summary
A refrigeration system for a mobile unit includes a refrigeration loop (32), an air duct (70), a sensor (34) and a shock absorption unit (36). The refrigeration loop includes a compressor, a condenser, a refrigerant regulator and an evaporator (64). The air duct directs air from an air inlet to the evaporator, which air duct is defined by first and second panels. The sensor is disposed in the air duct. The shock absorption unit mounts the sensor to and provides a limited thermal conduction path between the sensor and the first panel (22).