Flash Tank Subcooler Cooling for Low-Refrigerant Defrost
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Solution Overview
Problem
Existing cooling systems face challenges in maintaining sufficient refrigerant for hot gas defrost cycles, especially when operating at reduced capacity or in installations with limited space, leading to insufficient refrigerant availability for defrosting loads.
Innovation Solution
The integration of a subcooler heat exchanger that utilizes refrigerant stored in a flash tank to supply additional refrigerant to a low temperature compressor, either by transferring heat from a high side heat exchanger or an expansion valve, enabling defrost cycles even when not enough loads are operating in a refrigeration cycle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the system operates with fewer loads in refrigeration cycle to save space or reduce operation, then space utilization improves, but refrigerant availability for defrost decreases
Solution Approach 1:
The flash tank stores refrigerant in advance during periods when sufficient refrigerant is available (normal operation). This preliminary accumulation of refrigerant ensures that when defrost cycles are needed and fewer loads are operating, the stored refrigerant can be quickly deployed to maintain adequate defrost capability.
Solution Approach 2:
The subcooler heat exchanger acts as an intermediary device that transfers heat from the high side heat exchanger to the stored refrigerant in the flash tank. This intermediary mechanism enables the system to convert thermal energy from the condensing refrigerant into useful heat for defrosting, bridging the gap between refrigerant storage and defrost requirements.
2Use of energy by moving object
If the system reduces operation frequency or intensity, then energy consumption decreases, but refrigerant availability for defrost decreases
Solution Approach 1:
The flash tank accumulates refrigerant in advance during normal system operation. This preliminary storage ensures that when the system operates at reduced capacity, the stored refrigerant can be deployed to maintain sufficient defrost capability without requiring intensive continuous operation.
Solution Approach 2:
The high side heat exchanger provides heat to the subcooler heat exchanger, which in turn heats the stored refrigerant in the flash tank. This self-service mechanism allows the system to use its own operational heat to generate defrost capability, reducing the need for external energy input during reduced operation periods.
3Object-generated harmful factors
If hot gas defrost is implemented, then frost and ice accumulation is removed, but additional refrigerant is required beyond what is available in reduced operation
Solution Approach 1:
The flash tank extracts and stores refrigerant separately from the main system circulation. This extraction creates a dedicated reservoir of refrigerant specifically available for defrost operations, independent of the refrigerant needed for continuous cooling during reduced operation.
Solution Approach 2:
The subcooler heat exchanger serves as an intermediary that transfers heat to the stored refrigerant, enabling it to reach the necessary temperature and pressure conditions for effective defrost. This intermediary process allows the system to generate sufficient defrost capability without requiring a large increase in overall refrigerant quantity.
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 ensures sufficient refrigerant is available for defrosting loads, allows for faster defrosting, and reduces energy consumption of medium temperature load compressors, enabling effective defrosting even in scenarios with reduced refrigerant availability.
Implementation Method 1
A high side heat exchanger removes heat from a refrigerant
Implementation Method 2
The flash tank stores the refrigerant from the subcooler heat exchanger
Implementation Method 3
the subcooler heat exchanger receives the refrigerant from the flash tank, transfers heat from the refrigerant from the high side heat exchanger to the refrigerant from the flash tank
Implementation Method 4
the first compressor compresses the refrigerant from the first load
Implementation Method 5
the first load uses the refrigerant from the flash tank to cool a first space proximate the first load
Implementation Method 6
the first compressor compresses the refrigerant from the subcooler heat exchanger and directs the compressed refrigerant from the subcooler heat exchanger to the first load to defrost the first load
Data Source
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AI summary
An apparatus (200) includes a high side heat exchanger (105), a subcooler heat exchanger (205), a flash tank (110), a load (120A), and a compressor (130). The high side heat exchanger (105) removes heat from a refrigerant. The subcooler heat exchanger (205) receives the refrigerant. The flash tank (110) stores the refrigerant. During a first mode of operation, the load (120A) uses the refrigerant to cool a space proximate the load (120A and the compressor (130) compresses the refrigerant. During a second mode of operation, the subcooler heat exchanger (205) receives the refrigerant from the flash tank (110), transfers heat from the refrigerant from the high side heat exchanger (105) to the refrigerant from the flash tank (110) and directs the refrigerant from the flash tank (110) to the compressor (130). During the second mode of operation, the compressor (130) compresses the refrigerant from the subcooler heat exchanger (205) and directs the compressed refrigerant to the load (120A) to defrost the load (120A).