Passive Refrigerant Charge Receiver for High-Ambient Pressure Control
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Solution Overview
Problem
HVAC systems with microchannel heat exchangers face undesirable increases in subcooling and compressor discharge pressure due to excess migration of liquid phase refrigerant during high ambient temperature conditions, leading to efficiency losses and potential compressor shut-offs.
Innovation Solution
Incorporation of a passive charge management device with an internal volume and strategically located tubes to receive and manage excess liquid phase refrigerant, preventing its recirculation and reducing the effective refrigerant charge within the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If liquid phase refrigerant migrates to the condenser during high ambient temperature conditions, then the refrigerant charge increases, but subcooling and compressor discharge pressure increase undesirably
Solution Approach 1:
The patent extracts excess liquid phase refrigerant from the condenser by providing a dedicated receiver device that captures and holds the migrated refrigerant, preventing it from recirculating through the system and causing harmful pressure increases
2Quantity of substance
If liquid phase refrigerant migrates to the condenser during high ambient temperature conditions, then the refrigerant charge increases, but subcooling increases undesirably
Solution Approach 1:
The receiver device extracts excess liquid refrigerant from the condenser, removing the source of unwanted subcooling while maintaining the necessary refrigerant charge in the system
3Quantity of substance
If excess liquid phase refrigerant recirculates through the system, then the refrigerant charge is maintained, but efficiency losses occur
Solution Approach 1:
The receiver device acts as an intermediary component that intercepts excess liquid refrigerant before it can recirculate through the system, allowing the main system to maintain proper charge levels and efficiency
4Quantity of substance
If excess liquid phase refrigerant is present in the system, then the refrigerant charge increases, but compressor shut-offs may occur
Solution Approach 1:
The receiver device continuously extracts excess liquid refrigerant from the condenser, preventing the conditions that lead to compressor shut-offs and ensuring reliable operation
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
The passive charge management device effectively reduces subcooling and compressor discharge pressure, enhancing the system's tolerance to overcharging and high ambient temperatures, thereby preventing efficiency losses and compressor shut-offs.
Implementation Method 1
a passive charge management device that receives liquid phase refrigerant from the condenser heat exchanger when a vertical height of liquid refrigerant within the condenser heat exchanger exceeds a threshold vertical height
Data Source
AI summary
A heat exchanger has an upper region, a lower region disposed vertically lower than the upper region, and a passive charge management device. The passive charge management device has an internal volume, an upper tube connecting the internal volume to at least one of the upper region and the lower region at a first vertical height, and a lower tube connecting the internal volume to at least one of the upper region and the lower region at a second vertical height that is vertically lower than the first vertical height.