Refrigerating Circuit With Liquid Return Desuperheating

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Solution Overview

Problem

Refrigerating circuits face high thermal stress on compressor stages and condenser/gas cooler units due to high-pressure and high-temperature refrigerant flow, leading to reduced efficiency and shorter component lifetimes, particularly in booster installations where refrigerant from low temperature loops is transferred to medium temperature loops.

Innovation Solution

A refrigerating circuit design that includes a liquid refrigerant return line connected to the pressure line, using a pressure reduction means such as a venturi structure to locally reduce pressure and inject liquid refrigerant into the pressure line, thereby desuperheating the refrigerant before it enters downstream compressor stages or condenser/gas cooler units, reducing thermal stress and extending component lifespan.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If refrigerant is circulated at high pressure and temperature from compressor stages to condenser/gas cooler units, then cooling capacity and power transmission are improved, but thermal stress on components increases and component lifetime decreases

Engineering Contradiction:
Improvecooling capacityVSAvoidcomponent lifetime
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent applies preliminary action by injecting liquid refrigerant into the pressure line before the refrigerant reaches downstream compressor stages or condenser/gas cooler units. This pre-cooling action reduces the temperature of the refrigerant in advance, preventing thermal stress on downstream components while maintaining the high-pressure circulation needed for cooling capacity. The liquid refrigerant is introduced at a strategic point in the pressure line to achieve this preliminary cooling effect.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If liquid refrigerant is injected into the pressure line to desuperheat refrigerant, then thermal stress on downstream devices is reduced, but device complexity increases

Engineering Contradiction:
Improvecomponent lifetimeVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system applies self-service by utilizing the refrigerant itself as the cooling medium for desuperheating. The liquid refrigerant, which is already part of the refrigeration cycle, is injected into the pressure line to cool the superheated refrigerant. This eliminates the need for separate cooling systems or additional refrigerants, reducing overall system complexity while extending component lifetime through reduced thermal stress.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If pressure reduction means is used to locally reduce pressure in the pressure line, then liquid refrigerant injection is enabled, but manufacturing complexity increases

Engineering Contradiction:
Improverefrigerant injection capabilityVSAvoidinstallation complexity
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The patent applies the taking out principle by extracting a small, localized pressure reduction function from the overall high-pressure system. Instead of reducing pressure throughout the entire pressure line, a compact pressure reduction means is installed at a specific location to create a localized low-pressure zone. This allows liquid refrigerant injection at that point while maintaining high pressure in the rest of the system, minimizing manufacturing complexity and installation requirements.

Inventive Principle:
Principle #2Taking out (Extraction)

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 design effectively reduces thermal stress on downstream devices by desuperheating refrigerant, leading to increased efficiency and extended service life of components like condenser plates and compressors, without requiring significant additional installation efforts or efficiency losses.

Implementation Method 1

A refrigerating circuit design that includes a liquid refrigerant return line connected to the pressure line, using a pressure reduction means such as a venturi structure to locally reduce pressure

Methodology Applied
Scientific EffectVenturi effect: Venturi Effect

Implementation Method 2

injecting liquid refrigerant into the pressure line, thereby desuperheating the refrigerant before it enters downstream compressor stages or condenser/gas cooler units

Methodology Applied
Scientific EffectEvaporative cooling: Evaporative Cooler

Data Source

PatentEP2313711B1Refrigerating circuit
Publication Date: 2013.07.24 CARRIER CORP
  • EP2313711B1 patent drawingFigure 1~2
  • EP2313711B1 patent drawingFigure 3

AI summary

The invention relates to a refrigerating circuit (10) adapted to circulate, in operation, a refrigerant in a predetermined flow direction, said refrigerating circuit (10) comprising a compressor stage (12), said compressor stage (12) having a suction side and a pressure side, and at least one heat dissipating heat exchanging unit (14) connected to said pressure side of said compressor stage (12) via a pressure line (24), said heat dissipating heat exchanging unit (14) having an inlet side (14a) and an outlet side (14b) and including a condenser/gas cooler unit (16), and a liquid refrigerant return line (26) connecting said outlet side of said heat dissipating heat exchanging unit (14) to said pressure line (24).