Flash Tank Refrigerant Cooling for Compressor Overheat Prevention

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Refrigeration systems in CO2 booster configurations face unsafe operating conditions when the medium temperature load is not present or when loads are imbalanced, leading to overheating of medium temperature compressors due to high refrigerant temperatures.

Innovation Solution

The refrigerant from the low temperature compressor is routed through a flash tank below its liquid level line, where it is cooled by the liquid refrigerant, and then sent to the medium temperature compressor via a flash gas bypass line, ensuring safe operation by reducing the refrigerant temperature.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If refrigerant is cycled through the medium temperature compressor when the medium temperature load is not present, then the refrigeration system can maintain operation, but the medium temperature compressor overheats due to high refrigerant temperature

Engineering Contradiction:

Improvecompressor operation safetyVSAvoidrefrigerant temperature

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The flash tank serves as an intermediary device between the high side heat exchanger and the medium temperature compressor. It receives high temperature refrigerant, allows it to flash evaporate and cool down, and then supplies the cooled refrigerant to the medium temperature compressor. This mediator component resolves the temperature incompatibility without requiring fundamental system changes.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system utilizes phase transition of refrigerant in the flash tank where liquid refrigerant flashes to vapor, absorbing heat and cooling the incoming high temperature refrigerant. This phase change process naturally reduces the refrigerant temperature to safe levels for the medium temperature compressor without active cooling mechanisms.

Inventive Principle:

Principle #36Phase transitions

2Adaptability or versatility

If the medium temperature load is removed from the system, then the system can adapt to changing operational requirements, but the refrigerant temperature becomes too high for the medium temperature compressor

Engineering Contradiction:

Improvesystem operational flexibilityVSAvoidrefrigerant temperature

Core Design Contradiction:

Adaptability or versatilityVSTemperature

Solution Approach 1:

The flash tank performs preliminary cooling action on the refrigerant before it enters the medium temperature compressor. By pre-cooling the refrigerant through flash evaporation, the system prepares the refrigerant in advance to meet the temperature requirements of the compressor, ensuring safe operation during medium temperature load absence.

Inventive Principle:

Principle #10Preliminary action

3Device complexity

If refrigerant is routed directly to the medium temperature compressor without cooling, then the system configuration remains simple, but the compressor experiences overheating and potential failure

Engineering Contradiction:

Improvesystem configurationVSAvoidcompressor operation safety

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The flash tank is introduced as a relatively simple intermediary component that provides essential cooling function. While it does increase device complexity slightly, the added complexity is minimal compared to the significant improvement in compressor reliability and protection from overheating damage.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 configuration allows the medium temperature compressor to safely handle the refrigerant, preventing overheating and compressor failure, even when the medium temperature load is absent or imbalanced loads occur, by effectively cooling the refrigerant before it reaches the compressor.

Implementation Method 1

routing the superheated refrigerant to a flash tank below the liquid level line of the flash tank reduces the temperature of the superheated refrigerant

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

The flash tank stores the refrigerant from the high side heat exchanger. The load uses the refrigerant from the flash tank

Methodology Applied

Scientific EffectFlash evaporation: Flash Evaporation

Data Source

PatentUS9964339B2Cooling system with low temperature load

Publication Date: 2018.05.08 HEATCRAFT REFRIGERATION PRODUCTS LLC

AI summary

A system includes a flash tank, a load, a first compressor, a second compressor, a refrigerant routing line, and a flash gas bypass line. The flash tank stores a refrigerant. The load uses the refrigerant from the flash tank to remove heat from a space proximate the load. The first compressor compresses the refrigerant from the load. The refrigerant routing line routes the refrigerant from the first compressor to the flash tank below a liquid level line of the flash tank. The flash gas bypass line is coupled to the flash tank and sends the refrigerant as a flash gas from the flash tank to the second compressor. The second compressor compresses the refrigerant.