Cooling Layout Using Ejector Defrost Without Stepper Valves
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Solution Overview
Problem
Existing cooling systems require large piping and stepper valves to manage pressure for hot gas defrost cycles, increasing system footprint and cost due to the need for significant pressure differences across the refrigerant lines.
Innovation Solution
The cooling system employs a medium temperature compressor discharge to perform hot gas defrost without using a stepper valve, reducing the need for large piping and minimizing the amount of refrigerant and energy used.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a stepper valve and large piping are used to manage pressure for hot gas defrost cycles, then the pressure of hot gas can be regulated, but the system footprint and cost increase
Solution Approach 1:
The patent removes the stepper valve from the system entirely, extracting the pressure regulation function to the medium temperature compressor discharge line. This eliminates the need for large piping and reduces system footprint while maintaining pressure control for hot gas defrost cycles.
Solution Approach 2:
The medium temperature compressor discharge line serves multiple functions: it provides pressurized refrigerant for normal operation and simultaneously provides pressure-regulated hot gas for defrost cycles. This multi-functionality eliminates the need for separate pressure regulation components.
2Reliability
If a stepper valve and large piping are used to manage pressure for hot gas defrost cycles, then the pressure of hot gas can be regulated, but the system cost increases
Solution Approach 1:
The patent removes the expensive stepper valve component from the system, extracting its pressure regulation function to the existing medium temperature compressor discharge line. This elimination of specialized components directly reduces system cost while maintaining pressure control capability.
Solution Approach 2:
The medium temperature compressor discharge line performs multiple functions including normal refrigerant delivery and hot gas pressure regulation for defrost. This multi-functionality eliminates the need for additional expensive components, reducing overall system cost.
3Object-affected harmful factors
If hot gas defrost is performed using low temperature compressor discharge, then frost and ice can be removed from loads, but large piping is required to manage pressure differences
Solution Approach 1:
The patent changes the pressure parameter by using the medium temperature compressor discharge line, which naturally provides higher pressure refrigerant. This pressure difference enables hot gas defrost without requiring large piping to manage pressure gradients.
Solution Approach 2:
The patent removes the need for large pressure-managing piping by extracting the pressure regulation requirement to the medium temperature compressor discharge, which inherently provides the necessary pressure differential for effective defrosting.
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 reduces the system's cost, footprint, and energy consumption while maintaining effective defrosting capabilities, as the system can efficiently manage pressure without the need for extensive piping and valves.
Implementation Method 1
The cooling system directs refrigerant at a medium temperature compressor discharge to the loads to defrost the loads
Implementation Method 2
As the refrigerant passes through these metallic components, frost and/or ice may accumulate on the exterior of these metallic components. The ice and/or frost reduce the efficiency of the load. For example, as frost and/or ice accumulates on a load, it may become more difficult for the refrigerant within the load to absorb heat that is external to the load.
Data Source
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AI summary
An apparatus (200) includes a flash tank (110), a medium temperature load (115), a low temperature load (120A), a first compressor (130), a second compressor (125), and an ejector (230). The flash tank (110) stores a refrigerant. The medium temperature load (115) uses the refrigerant from the flash tank (110) to cool a space proximate the medium temperature load (115) to a first temperature. The low temperature load (120A) uses the refrigerant from the flash tank (110) to cool a space proximate the low temperature load (120A) to a second temperature that is lower than the first temperature. The first compressor (130) compresses the refrigerant from the low temperature load (120A). The second compressor (125) compresses the refrigerant from the medium temperature load (115). The ejector (230) directs a mixture of the refrigerant from the first compressor (130) and the refrigerant from the second compressor (125) to the low temperature load (120A) during a defrost cycle. The mixture defrosts the low temperature load (120A). The flash tank (110) receives the mixture.