Cooling system with flooded low side heat exchangers
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Solution Overview
Problem
In cooling systems lacking medium temperature low side heat exchangers, the medium temperature compressor compresses mostly high-temperature refrigerant from the low temperature section, leading to efficiency drops.
Innovation Solution
The system floods low temperature low side heat exchangers and uses an accumulator to collect refrigerant from these exchangers, transferring heat from the low temperature compressor's discharge to the collected refrigerant, thereby cooling it before it reaches the medium temperature compressor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the system lacks medium temperature low side heat exchangers, then the system structure is simplified, but the medium temperature compressor efficiency drops due to compressing high-temperature refrigerant
Solution Approach 1:
The patent introduces an accumulator as an intermediary component between the low temperature low side heat exchangers and the medium temperature compressor. The accumulator collects refrigerant from the flooded heat exchangers and allows heat transfer from the low temperature compressor discharge to cool the collected refrigerant before it enters the medium temperature compressor, thereby resolving the efficiency problem without adding medium temperature heat exchangers
Solution Approach 2:
The patent combines the functions of refrigerant collection, heat transfer, and cooling into a single accumulator component. The accumulator serves multiple purposes: collecting two-phase refrigerant from flooded heat exchangers, receiving heat transfer from compressor discharge, and delivering cooled refrigerant to the medium temperature compressor, thereby simplifying the overall system structure
2Quantity of substance
If low temperature low side heat exchangers are flooded, then more refrigerant is collected for heat transfer, but liquid refrigerant may enter the compressor causing damage
Solution Approach 1:
The patent segments the accumulator into distinct functional zones: a liquid collection section at the bottom, a heat transfer section in the middle, and a vapor discharge section at the top. This segmentation allows liquid refrigerant to be collected and evaporated separately from the compression process, preventing liquid slugging while maximizing refrigerant utilization for heat transfer
Solution Approach 2:
The patent implements preliminary evaporation of liquid refrigerant within the accumulator before the refrigerant enters the medium temperature compressor. The accumulator provides a space where liquid refrigerant can evaporate and mix with vapor phase refrigerant, ensuring that only two-phase or vapor refrigerant enters the compressor, thereby protecting it from liquid damage
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 temperature of the refrigerant reaching the medium temperature compressor, enhancing its efficiency.
Implementation Method 1
The accumulator transfers heat from the refrigerant discharged by the first compressor to the refrigerant collected by the accumulator from the first and second low side heat exchangers
Data Source
AI summary
A cooling system partially floods the low temperature low side heat exchangers (e.g., freezers) in the system. An accumulator is positioned between the low temperature low side heat exchangers and the low temperature compressor. The accumulator collects the refrigerant (both liquid and vapor) from the flooded low temperature low side heat exchangers. Refrigerant discharged by the low temperature compressor is fed through the accumulator so that heat can be transferred to the refrigerant collected in the accumulator. As a result, the temperature of the refrigerant discharged by the low temperature compressor drops before that refrigerant reaches the medium temperature compressor.