On-demand micro expansion valve for a refrigeration system
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Solution Overview
Problem
Fixed orifice refrigeration systems take an undesirably long time to achieve target refrigeration temperature during transient conditions such as increased cooling load demands, as they are not adaptable to varying operating conditions.
Innovation Solution
Incorporating a micro-expansion valve in parallel with the expansion device, which allows for variable fluid flow adjustment based on changing conditions by using a microvalve with actuator ribs that expand and contract to control fluid ports, enabling rapid response to increased cooling demands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a fixed orifice expansion device is used, then the system is simple and cost-effective, but the system takes an undesirably long time to achieve target refrigeration temperature during transient conditions
Solution Approach 1:
The patent applies the dynamics principle by replacing the fixed orifice with a micro-expansion valve that can dynamically adjust its opening degree in response to changing operating conditions. The microvalve includes a movable valve element that can transition between different positions to modulate refrigerant flow, enabling the system to rapidly respond to transient cooling demands while maintaining simplicity through integrated micromachined construction.
2Device complexity
If a fixed orifice expansion device is used, then the device complexity is low, but the system is not adaptable to varying operating conditions
Solution Approach 1:
The micro-expansion valve incorporates a movable valve element that can dynamically adjust its position to modulate refrigerant flow according to varying operating conditions. This dynamic capability allows the system to adapt to transient cooling demands while maintaining relatively low device complexity through integrated micromachined construction and a compact design that combines multiple functions within a single component.
Solution Approach 2:
The microvalve device is designed to be self-regulating through its integrated structure, where the movable valve element responds automatically to pressure differential changes across the valve. This self-service mechanism eliminates the need for complex external control systems while providing adaptability to varying operating conditions, thereby maintaining low device complexity.
3Speed
If a micro-expansion valve is added in parallel, then the system responds rapidly to increased cooling demands, but the device complexity increases
Solution Approach 1:
The patent applies segmentation by introducing a parallel micro-expansion valve pathway alongside the traditional expansion device. This segmented approach allows the microvalve to handle transient high-demand scenarios independently, providing rapid response capability. The micromachined construction of the microvalve integrates multiple components into a compact unit, minimizing the increase in overall device complexity while achieving the desired speed improvement.
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 system rapidly adjusts to meet increased cooling demands, ensuring optimal operation during transient conditions while maintaining simplicity and cost-effectiveness.
Implementation Method 1
the actuator ribs that expand and contract to control fluid ports
Data Source
AI summary
A refrigeration system includes a compressor, a condenser fluidly connected to the compressor, an evaporator fluidly connected to the condenser and the compressor, such that fluid may flow from the compressor through the condenser, through the evaporator, and again through the compressor. An expansion device is fluidly connected between the condenser and the evaporator, and a micro-expansion valve is also connected between the condenser and the evaporator.