Microchannel Heat Exchanger Sensors for Direct Fluid Measurement

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Solution Overview

Problem

The challenge in accurately measuring the temperature of working fluids in stacked microchannel heat exchangers due to surface temperature measurements being influenced by heat conduction and air conduction, leading to measurement errors, and the cumbersome process of connecting temperature sensors directly to the pipes for accurate readings.

Innovation Solution

Incorporating a printed board with integrated temperature sensors and a wireless or wired transmission device to directly measure fluid temperatures, reducing errors by placing sensors in contact with the fluid and simplifying the connection process through a display device and heater integration near low-temperature channels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If temperature sensors are attached to the outer surface of pipes by soldering, then the connection process is simplified, but measurement precision deteriorates due to heat conduction errors and temperature boundary layers

Engineering Contradiction:
Improvesensor installation easeVSAvoidtemperature measurement accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent introduces a temperature measurement element that directly contacts the working fluid through the pipe wall opening, using the fluid itself as an intermediary to eliminate heat conduction errors through pipe walls. This direct contact measurement approach resolves the contradiction by achieving both accurate measurement and simplified installation compared to traditional soldering methods.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent extracts the temperature sensing function from the pipe wall surface attachment method and relocates it to direct contact with the working fluid through the pipe opening. This separation allows the sensor to measure the actual fluid temperature without being influenced by external heat conduction, while the pipe structure remains intact.

Inventive Principle:
Principle #2Taking out (Extraction)

2Measurement precision

If temperature sensors are inserted into pipes for direct fluid contact, then measurement precision improves, but device complexity increases due to additional connection components

Engineering Contradiction:
Improvetemperature measurement accuracyVSAvoidsensor connection complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the temperature measurement element with the pipe structure itself by utilizing the pipe wall opening as the insertion path and the pipe material as part of the measurement system. This integration eliminates separate connection components and reduces overall device complexity while maintaining direct fluid contact for accurate measurement.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The pipe structure serves multiple functions: it acts as both the fluid conduit and the mounting structure for the temperature measurement element. The pipe wall opening serves dual purposes as both a flow passage and the insertion path for the sensor, reducing the need for additional specialized components.

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

3Adaptability or versatility

If multiple temperature sensors are installed on pipe surfaces, then temperature monitoring capability is improved, but measurement precision deteriorates due to heat conduction and air conduction errors

Engineering Contradiction:
Improvetemperature monitoring capabilityVSAvoidtemperature measurement accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent uses the working fluid as an intermediary medium for heat transfer to the measurement element, eliminating the need for heat conduction through pipe walls and external mounting structures. This approach allows multiple sensors to be installed without introducing heat conduction errors, as each sensor directly contacts the fluid it measures.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the temperature measurement function into individual points of direct fluid contact, with each measurement element independently contacting the working fluid at its specific location. This segmentation allows multiple measurements to be taken simultaneously without mutual interference or heat conduction errors between sensors.

Inventive Principle:
Principle #1Segmentation

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

Facilitates accurate temperature measurement of working fluids, reduces measurement errors, and streamlines the connection process for sensors, enhancing the efficiency of temperature control in heat exchangers.

Implementation Method 1

the heat transfer plates and the metal plates are diffusion-welded and integrated with one another

Methodology Applied
Scientific EffectDiffusion-welding: Diffusion Welding

Implementation Method 2

The temperature sensors need to be capable of correctly measuring temperatures of working fluids

Methodology Applied
Scientific EffectThermal energy detection: Thermocouple

Implementation Method 3

the measured temperature has an error 1 due to heat conduction of the metal forming the heat exchanger

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Data Source

PatentEP3348976B1Microchannel heat exchanger
Publication Date: 2020.02.19 FUJITSU GENERAL LTD
  • EP3348976B1 patent drawingFigure 1
  • EP3348976B1 patent drawingFigure 2
  • EP3348976B1 patent drawingFigure 3

AI summary

This microchannel heat exchanger includes: a heat exchanger body including a channel layer stack formed in such a manner that a plurality of high-temperature channel layers provided with a channel for a high-temperature fluid and a plurality of low-temperature channels layers provided with a channel for a low-temperature fluid are alternately stacked, an inlet and an outlet for the high-temperature fluid, and an inlet and an outlet for the low-temperature fluid; and a control board that is fixed in a stacking direction of the heat exchanger body, and that at least installs a plurality of temperature sensors that are inserted in the stacking method of the heat exchanger body in such a manner that a sensing point is arranged near each of the inlet and the outlet for the high-temperature fluid and the inlet and the outlet for the low-temperature fluid.