Linear Compressor Discharge Plenum for Heat Isolation and Cooling
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Solution Overview
Problem
Linear compressors face issues with overheating, leading to reduced compression efficiency due to high-temperature refrigerant transfer between the piston, cylinder, and discharge cover, as well as increased weight and operational frequency limitations from the driving part's design.
Innovation Solution
The introduction of a discharge plenum that comes into close contact with the discharge cover and a structure for decreasing the temperature of the bearing refrigerant between the cylinder and piston, utilizing multiple flow paths for the refrigerant as a bearing, which minimizes heat transfer and conduction, and enhances heat dissipation through convection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If refrigerant discharged from the compression space flows into the discharge cover, then the discharge cover is overheated, but heat transfer to the frame and piston-cylinder assembly reduces compression efficiency
Solution Approach 1:
The discharge cover is segmented into an insulating layer and a heat-dissipating layer. The insulating layer prevents heat transfer to the frame and piston-cylinder assembly, while the heat-dissipating layer manages the heat from the discharged refrigerant through convection and radiation, thus maintaining compression efficiency while controlling discharge cover temperature.
Solution Approach 2:
An insulating layer is introduced as an intermediary between the discharge cover and the frame/piston-cylinder assembly. This intermediary prevents harmful heat conduction to these components, thereby maintaining compression efficiency while allowing the discharge cover to handle the hot discharged refrigerant.
2Temperature
If the discharge cover has a large surface area to dissipate heat, then heat dissipation improves, but the weight of the driving part increases
Solution Approach 1:
The discharge cover uses a composite structure consisting of an insulating layer (such as foam or air gap) and a heat-dissipating layer (such as metal with high thermal conductivity). This composite material approach provides effective heat dissipation through convection and radiation from the outer surface while minimizing heat conduction to internal components and reducing the overall weight compared to a solid metal structure.
Solution Approach 2:
Different regions of the discharge cover have different thermal properties. The insulating layer is positioned where heat conduction would be harmful (toward the frame and piston-cylinder), while the heat-dissipating layer is positioned at the outer surface where heat can be dissipated to the environment through convection and radiation. This local differentiation optimizes both heat management and weight.
3Productivity
If bearing refrigerant is supplied to the piston-cylinder assembly to reduce friction, then compression efficiency improves, but the refrigerant becomes overheated
Solution Approach 1:
The function of cooling the bearing refrigerant is extracted from the discharge cover and assigned to a separate refrigerant management system. This allows the discharge cover to focus on heat dissipation while the bearing refrigerant is cooled independently, preventing overheating and maintaining compression efficiency.
Solution Approach 2:
The bearing refrigerant is cooled in advance before being supplied to the piston-cylinder assembly. This preliminary cooling action ensures that the refrigerant enters the compression chamber at an appropriate temperature, preventing overheating and maintaining high compression efficiency throughout the compression process.
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 prevents overheating of the piston and cylinder, maintains compression efficiency, reduces material costs by minimizing the discharge cover's surface area, and allows for higher operating frequencies by reducing heat transfer and conduction.
Implementation Method 1
a discharge plenum placed in close contact with the discharge cover in order to prevent an increase in temperature of the discharge cover due to refrigerant discharged from a compression space
Implementation Method 2
enhances heat dissipation through convection
Implementation Method 3
a gas pocket configured to communicate with the gas hole and deliver a refrigerant gas into the cylinder. The refrigerant gas may function as a gas bearing between the cylinder and the piston to reduce frictional force
Data Source
AI summary
Disclosed is a linear compressor. The linear compressor according to the spirit of the present invention includes a cylinder forming a compression space for refrigerant and a discharge unit forming a discharge space for refrigerant into which refrigerant discharged from the compression space flows. The discharge unit includes a discharge cover having an inner space formed therein and a discharge plenum placed in the inner space. In this case, the discharge plenum includes a plenum flange extending radially, a plenum seating part, a plenum body, and a plenum extension part which extend from a radially inner side end of the plenum flange, and a plenum guide surface extending from a radially outer side end of the plenum flange toward the inner space.