Refrigeration device controlling a temperature of compressor-discharged refrigerant

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Solution Overview

Problem

Refrigeration apparatuses using fluorocarbons like HFO-1123 face challenges in preventing disproportionation reactions due to temperature rises in high-pressure refrigerants, as existing temperature control methods are ineffective in maintaining the refrigerant temperature below the reaction threshold, leading to potential decomposition and environmental concerns.

Innovation Solution

A refrigeration apparatus with a compressor and refrigerant circuit that includes a refrigerant temperature detection unit and control unit to monitor and control the discharged refrigerant temperature to ensure it remains below the predetermined temperature threshold, using either direct temperature measurement or estimation based on the operating state, and incorporating a muffler-side temperature sensor for noise reduction and accurate temperature detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a temperature sensor is provided in a discharge pipe to control refrigerant temperature, then the refrigerant temperature in the discharge pipe can be controlled to be equal to or lower than a predetermined temperature, but the temperature of the refrigerant discharged from the compression mechanism may still exceed the predetermined temperature due to heat dissipation to the surrounding air

Engineering Contradiction:

Improverefrigerant temperature in discharge pipeVSAvoidtemperature control reliability

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

Instead of measuring temperature downstream in the discharge pipe where heat dissipation occurs, the patent places the temperature sensor upstream at the discharge port of the compression mechanism. This inverts the measurement location to where the refrigerant temperature is highest and most representative, eliminating the error caused by heat dissipation to surrounding air.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The temperature is measured at the discharge port immediately after compression, before the refrigerant enters the discharge pipe where heat dissipation occurs. This preliminary measurement allows the control system to adjust compression parameters proactively to prevent temperature exceedance, rather than reacting after heat loss has already occurred.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If the refrigerant temperature is controlled to be equal to or lower than a predetermined temperature to prevent disproportionation reaction, then the reliability of preventing disproportionation reaction improves, but the device complexity increases due to additional temperature sensors and control mechanisms

Engineering Contradiction:

Improvedisproportionation reaction preventionVSAvoidtemperature control system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The temperature sensor is integrated directly into the discharge port of the compression mechanism, merging the measurement function with the existing structural components. This eliminates the need for separate external temperature control devices and reduces overall system complexity while maintaining reliable temperature monitoring.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The compression mechanism itself provides the temperature measurement capability through the integrated sensor at its discharge port. The system uses its own structural components and operating parameters for self-monitoring and self-control, eliminating the need for additional external control systems.

Inventive Principle:

Principle #25Self-service

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 effectively prevents the disproportionation reaction of high-pressure refrigerants by ensuring the discharged refrigerant temperature is maintained below the critical threshold, enhancing the reliability of the refrigeration cycle and reducing environmental impact.

Implementation Method 1

a refrigerant temperature detection unit (61, 62, 91) for detecting a discharged refrigerant temperature which is a temperature of the refrigerant that is being discharged from the compression mechanism (40) or immediately after the discharge

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a compression mechanism (40) driven by the electric motor (32) and configured to discharge the refrigerant, which has been compressed, into an internal space (S) of the casing (31)

Methodology Applied

Scientific EffectCompression heating: Compression

Data Source

PatentUS11143446B2Refrigeration device controlling a temperature of compressor-discharged refrigerant

Publication Date: 2021.10.12 DAIKIN INDUSTRIES LTD

AI summary

As a refrigerant, a refrigerant containing a fluorocarbon having a property of causing a disproportionation reaction is used. A refrigeration apparatus includes: a refrigerant temperature detector configured to detect a discharged refrigerant temperature which is a temperature of the refrigerant that is being discharged from the compression mechanism or immediately after the discharge; and a controller configured to control the discharged refrigerant temperature detected by the refrigerant temperature detector such that the discharged refrigerant temperature is equal to or lower than a predetermined temperature Ts.