Compressor Flooded Start Cycling for Liquid Refrigerant Control

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Compressors in refrigeration systems face operational issues due to flooding with liquid refrigerant, leading to lubricant depletion and potential damage, especially during startup, as traditional crankcase heaters are inefficient and increase energy costs.

Innovation Solution

A system and method for flooded start control that uses temperature sensors and a control module to implement cycling on/off operations, allowing gradual pumping of liquid refrigerant, thereby allowing lubricant to return to the compressor and reducing the need for crankcase heaters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the compressor operates continuously in a flooded state, then liquid refrigerant is quickly pumped out, but the lubricant is depleted and compressor damage occurs

Engineering Contradiction:

Improveliquid refrigerant pumping speedVSAvoidcompressor reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent implements periodic on/off cycling of the compressor during flooded start conditions. The control module monitors liquid refrigerant levels and cycles the compressor between on and off states, allowing liquid to be gradually pumped out while preventing complete lubricant depletion. This periodic action resolves the contradiction by maintaining productivity through continuous operation while protecting reliability through strategic shutdowns.

Inventive Principle:

Principle #19Periodic action

2Reliability

If crankcase heaters are used to prevent liquid migration, then compressor flooding is reduced, but energy consumption increases

Engineering Contradiction:

Improvecompressor protection from floodingVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent enables the compressor to protect itself from flooding through intelligent control algorithms that monitor liquid refrigerant levels and control compressor cycling. This self-service approach eliminates or reduces the need for external crankcase heaters, maintaining compressor protection while significantly reducing energy consumption. The control module uses temperature sensors and liquid level detection to autonomously manage flooded start conditions.

Inventive Principle:

Principle #25Self-service

3Reliability

If the compressor is cycled on/off to allow lubricant return, then lubrication is maintained, but operation time is extended

Engineering Contradiction:

Improvelubrication maintenanceVSAvoidcompressor operation time

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent implements feedback control where the control module continuously monitors liquid refrigerant levels, compressor temperature, and operating conditions. Based on this feedback, the control module dynamically adjusts the on/off cycling strategy to maintain adequate lubrication while minimizing extended operation time. The feedback loop ensures that cycling is applied only when necessary for lubricant return, resolving the contradiction between lubrication maintenance and operation duration.

Inventive Principle:

Principle #23Feedback

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 approach extends the time for lubricant return, reduces energy consumption, and prevents compressor damage by managing liquid refrigerant and lubricant effectively during startup, potentially eliminating the need for crankcase heaters.

Implementation Method 1

A temperature sensor that generates temperature data corresponding to at least one of a compressor temperature and an ambient temperature

Methodology Applied

Scientific EffectTemperature sensing:

Implementation Method 2

determines an amount of liquid present in the compressor based on the temperature data and the off-time period... operates the compressor according to at least one cycle including a first time period during which the compressor is on and a second time period during which the compressor is off

Methodology Applied

Scientific EffectLiquid refrigerant pumping:

Data Source

PatentUS9194393B2Compressor with flooded start control

Publication Date: 2015.11.24 COPELAND LP

AI summary

A system and method for flooded start control of a compressor for a refrigeration system is provided. A temperature sensor generates temperature data corresponding to at least one of a compressor temperature and an ambient temperature. A control module receives the temperature data, determines an off-time period since the compressor was last on, determines an amount of liquid present in the compressor based on the temperature data and the off-time period, compares the amount of liquid with a predetermined threshold, and, when the amount of liquid is greater than the predetermined threshold, operates the compressor according to at least one cycle including a first time period during which the compressor is on and a second time period during which the compressor is off.