Compressor Sump Segmentation for Refrigerant Dissolution
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Solution Overview
Problem
In laundry dryers with heat pumps using flammable refrigerants like R290 and R1270, the excessive amount of lubricating oil required for proper lubrication exceeds the minimum necessary, leading to significant refrigerant dissolution, which limits the available refrigerant for circulation and affects operational conditions.
Innovation Solution
A solid insert is placed within the compressor's sump to reduce the volume occupied by oil, allowing a lower amount of lubricating oil to be used, thereby minimizing refrigerant dissolution and maximizing the refrigerant available for circulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sufficient amount of lubricating oil is provided in the sump for proper pump lubrication, then the pump is adequately lubricated, but the amount of refrigerant dissolved in the oil increases, reducing the refrigerant available for circulation
Solution Approach 1:
The sump is segmented into two functional zones: an oil storage region and a refrigerant return region. The refrigerant return region is positioned adjacent to the pump inlet, ensuring that refrigerant can be efficiently drawn from this zone while oil remains in the storage region. This spatial segmentation allows the pump to receive refrigerant without requiring excessive oil volume, thereby reducing refrigerant dissolution while maintaining adequate lubrication.
Solution Approach 2:
A refrigerant return passage acts as an intermediary channel between the sump and the pump inlet. This passage preferentially conduits refrigerant from the refrigerant return region to the pump, creating a dedicated flow path that minimizes the need for large oil volumes. The intermediary passage ensures that refrigerant can be supplied to the pump without being mixed with excessive amounts of oil, thus reducing refrigerant dissolution while maintaining lubrication.
2Quantity of substance
If the sump volume is reduced to minimize refrigerant dissolution, then more refrigerant is available for circulation, but the pump may not receive adequate lubrication
Solution Approach 1:
Different regions of the sump are assigned different functional qualities: the oil storage region is optimized for containing lubricating oil, while the refrigerant return region is optimized for supplying refrigerant to the pump. This local differentiation allows the sump to maintain adequate oil volume for lubrication in the storage region while keeping the overall oil volume low enough to minimize refrigerant dissolution. The refrigerant return region ensures the pump receives refrigerant preferentially.
3Object-affected harmful factors
If the amount of refrigerant is limited to comply with safety regulations, then safety requirements are met, but the operational performance of the heat pump is affected due to refrigerant dissolution in oil
Solution Approach 1:
The invention converts the potential harm of refrigerant-oil contact into a benefit by designing a sump structure that minimizes refrigerant dissolution. The segmented sump with preferential refrigerant return paths ensures that refrigerant is efficiently supplied to the pump with minimal loss to dissolution. This allows the heat pump to operate with the maximum permitted refrigerant charge while maintaining optimal performance, effectively turning the safety limitation into an opportunity for optimized design.
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 reduces the amount of refrigerant dissolved in the lubricating oil, ensuring a larger fraction of the total refrigerant is available for heat pump operation, enhancing performance and compliance with safety regulations.
Implementation Method 1
a compressor for compressing a refrigerant
Implementation Method 2
The refrigerant circulates within a refrigerant circuit and is compressed by the compressor
Implementation Method 3
a sump for containing an amount of lubricating oil to a predetermined level
Implementation Method 4
The refrigerant circulates within a refrigerant circuit and is compressed by the compressor
Implementation Method 5
The refrigerant circulates within a refrigerant circuit
Data Source
Figure 1
Figure 2~3
Figure 4~6
AI summary
Compressor (9) for compressing a refrigerant, comprising a housing (11) for containing said refrigerant, a refrigerant pump (10), said pump (10) disposed within said housing (11), and a sump (13) for containing an amount of lubricating oil to a predetermined level (14) is defined within said housing (11) separate from said refrigerant pump (10). Said housing (11) includes means (15, 12) for reducing the amount of lubricating oil contained in said sump (13) while maintaining said level (14). The invention also relates to a heat pump (5, 6, 7, 8, 9) including such compressor (9), the heat pump (5, 6, 7, 8, 9) preferably being contained in a laundry dryer (1).