Dedicated Defrost-Mode Compressor for Multi-Evaporator Hot Gas Defrost
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Solution Overview
Problem
Existing refrigeration systems face inefficiencies in evaporator defrosting, requiring long times and high energy consumption, and are often unable to effectively defrost multiple evaporators simultaneously.
Innovation Solution
A refrigeration system utilizing a dedicated defrost-mode compressor operating at higher suction and discharge pressures, with a corresponding suction and discharge line configuration, and a heat exchanger to provide warmed and compressed refrigerant for efficient defrosting, while preventing excessive pressure that could damage evaporators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If previous defrost processes are used, then evaporators can be defrosted, but the process takes a relatively long time and consumes a relatively large amount of energy
Solution Approach 1:
The patent changes the operating parameters of the compressor by introducing a dedicated defrost-mode compressor that operates at higher suction pressure and discharge pressure than typical low temperature compressors. This parameter change enables faster defrosting while improving energy efficiency through optimized pressure differential for refrigerant flow.
Solution Approach 2:
The patent segments the compressor function by introducing a dedicated defrost-mode compressor separate from the low temperature compressor. This segmentation allows each compressor to be optimized for its specific function - the defrost-mode compressor for rapid defrosting and the low temperature compressor for normal refrigeration operation.
2Productivity
If previous defrost processes are used, then some evaporators can be defrosted, but the system is incapable of providing adequate defrosting when a relatively large number of evaporators need to be defrosted
Solution Approach 1:
The dedicated defrost-mode compressor is designed to serve multiple evaporators simultaneously, providing universal defrost capability across the entire refrigeration system. The compressor can distribute heated refrigerant to multiple evaporator circuits, enabling adequate defrosting of a large number of evaporators.
Solution Approach 2:
The patent introduces an intermediary heat exchanger that receives superheated gas from the defrost-mode compressor and distributes it to multiple evaporators. This intermediary component enables the single compressor to effectively serve multiple evaporators by acting as a distribution hub.
3Productivity
If a dedicated defrost-mode compressor operating at higher pressures is used, then defrost performance is improved, but excessive pressure may damage evaporators
Solution Approach 1:
The patent incorporates a pressure switch in the discharge line that provides feedback control to prevent excessive pressure from reaching the evaporators. The pressure switch monitors the discharge pressure and automatically interrupts the refrigerant flow when a predetermined pressure threshold is reached, protecting the evaporators from damage while maintaining effective defrost performance.
4Productivity
If low-temperature compressors operate at increased pressure to provide defrost, then defrosting can be achieved, but power consumption increases unnecessarily
Solution Approach 1:
The patent segments the compressor functions by introducing a dedicated defrost-mode compressor that operates only during defrost cycles. This allows the low-temperature compressor to maintain its optimized low-pressure operation for refrigeration, while the defrost-mode compressor handles defrosting at higher pressures, preventing unnecessary power consumption increases in the low-temperature compressor.
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 improves defrost performance and energy efficiency by ensuring effective defrosting of multiple evaporators while maintaining normal operation of low-temperature compressors without increased power consumption, and reduces energy usage through supplemental cooling.
Implementation Method 1
the heat exchanger is configured to receive a portion of refrigerant stored by the flash tank and transfer heat to the received portion of refrigerant from the refrigerant cooled by the gas cooler, thereby heating the received portion of refrigerant
Implementation Method 2
The gas cooler is configured to receive high pressure, high temperature refrigerant and facilitate heat transfer from the received refrigerant to ambient air, thereby cooling the refrigerant
Implementation Method 3
the defrost-mode compressor is configured, while turned on, to compress this heated refrigerant to high pressure and deliver to the first evaporator unit
Data Source
AI summary
A refrigeration system includes a dedicated defrost-mode compressor that delivers high pressure, high temperature refrigerant to one or more evaporators to defrost the evaporators.