Refrigeration system and method of refrigeration load control

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Solution Overview

Problem

Existing refrigeration systems lack the ability to actively monitor and adjust medium temperature circuits in response to low temperature compressor failures, leading to inefficient refrigeration load management and inability to modulate refrigerant flow between medium and low temperature suction groups.

Innovation Solution

Incorporating an electronic valve in a bypass line between the medium and low temperature suction groups, controlled by a controller to selectively manage refrigerant flow, allowing for load shifting, emergency redundant control, and incremental capacity staging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a mechanical pressure regulating valve is installed between the low temperature suction group and the medium temperature group, then refrigerant flow can be regulated between the two groups, but the system cannot actively monitor compressor status or adjust setpoints dynamically

Engineering Contradiction:

Improverefrigeration load management flexibilityVSAvoidcontrol mechanism complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent replaces mechanical pressure regulating valves with an electronically controlled valve system. The electronic valve receives control signals from a controller that monitors compressor status and refrigeration load, enabling dynamic adjustment of refrigerant flow between medium and low temperature suction groups without complex mechanical linkages

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The controller actively monitors the low temperature compressor status and refrigeration load conditions, then adjusts the electronic valve position accordingly. This feedback mechanism enables the system to respond dynamically to changing conditions, optimizing refrigeration load management while maintaining simple control architecture

Inventive Principle:

Principle #23Feedback

2Reliability

If a check valve is installed between the low temperature suction header and the medium temperature suction header, then refrigerant can flow from low temperature to medium temperature header during compressor failure, but the system cannot actively monitor or adjust refrigerant flow

Engineering Contradiction:

Improvecompressor failure toleranceVSAvoidactive monitoring and adjustment capability

Core Design Contradiction:

ReliabilityVSExtent of automation

Solution Approach 1:

The patent replaces passive mechanical check valves with an electronically controlled valve system that can actively monitor compressor status through sensors and adjust refrigerant flow direction and magnitude dynamically. The controller detects compressor failure conditions and activates the electronic valve to redirect refrigerant flow, providing both reliability and automation

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system automatically detects compressor failure through monitoring sensors and self-adjusts the refrigerant flow configuration without manual intervention. The controller manages the electronic valve to maintain system reliability during failure conditions, eliminating the need for complex manual override mechanisms

Inventive Principle:

Principle #25Self-service

3Productivity

If multiple compressors in parallel arrangement are used to provide refrigerant to multiple evaporators, then refrigeration capacity can be increased, but suction pressure control becomes more complex and requires sophisticated control algorithms

Engineering Contradiction:

Improverefrigeration capacityVSAvoidsuction pressure control complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent introduces an electronic valve as an intermediary device between the parallel compressor groups and the evaporators. This valve acts as a flow mediator that the controller can adjust to balance refrigerant distribution, simplifying the control of suction pressure across multiple compressors while maintaining high refrigeration capacity

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system uses a dynamically controllable electronic valve that can adjust its opening position in real-time based on suction pressure feedback and refrigeration load conditions. This dynamic control enables sophisticated pressure management across parallel compressors without requiring complex fixed mechanical control mechanisms

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS11268744B2Refrigeration system and method of refrigeration load control

Publication Date: 2022.03.08 HUSSMANN CORP

AI summary

A method of controlling a refrigeration system including a medium temperature refrigeration load and a low temperature refrigeration load. The method includes selectively bypassing refrigerant between a medium temperature suction group and a low temperature suction group via a bypass line using an electronic valve positioned in the bypass line. The method also includes controlling flow of refrigerant between the medium temperature suction group and the low temperature suction group via a controller communicatively coupled to the valve, and modulating the valve at any position between a closed position and a full open position to vary an amount of refrigerant flow between the medium temperature suction group and the low temperature suction group in response to determining, via the controller, one or both of a state of the medium temperature suction group and a state of the low temperature suction group.