Cold Plate With Integrated TXV for Uniform Refrigerant Control
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Solution Overview
Problem
Conventional vapor compression cooling systems face challenges in maintaining uniform temperature across discrete heat loads due to high fluid velocity and pressure loss, leading to component failure and increased complexity, especially as the number of cold plates increases.
Innovation Solution
Integrating compact thermostatic expansion devices (TXVs) directly into each cold plate, with a sensing element immersed in the refrigerant stream, eliminates the need for external capillary tubes and push rods, allowing for localized control and simplified plumbing, reducing pressure drop and complexity while enabling precise temperature control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If distributors with discrete orifices are used to supply cooling to discrete heat loads, then flow distribution between conduits is near uniform, but pressure loss is considerable
Solution Approach 1:
The system segments the cooling function by integrating an individual thermostatic expansion device (TXV) into each cold plate, allowing each cold plate to independently control its refrigerant flow. This eliminates the need for a central distributor with multiple orifices, thereby reducing overall pressure loss while maintaining uniform flow distribution across discrete heat loads.
Solution Approach 2:
Each cold plate is equipped with its own TXV that locally adjusts refrigerant flow based on the specific thermal conditions of that cold plate. This localized control enables precise flow regulation at each heat load location, achieving uniform flow distribution without the high pressure losses associated with centralized distributors.
2Quantity of substance
If the number of discrete cold plates increases, then cooling capacity is improved, but the size, weight, and complexity of plumbing increases dramatically
Solution Approach 1:
The TXV is merged with the cold plate structure, integrating the expansion device directly into each cold plate. This integration eliminates the need for complex external plumbing and distributor systems, allowing the system to scale to multiple cold plates without proportionally increasing plumbing complexity, size, or weight.
Solution Approach 2:
Each cold plate operates as an independent module with its own integrated TXV, allowing the system to scale by simply adding more identical modules. This segmentation eliminates the need for complex centralized distribution systems that would require increasingly complex plumbing as the number of cold plates increases.
3Manufacturing precision
If conventional TXV with external sensing bulb and capillary tube is used, then temperature control is achieved, but response time is slow
Solution Approach 1:
The sensing element is merged with the TXV and positioned to directly contact the refrigerant at the cold plate outlet. This integration eliminates the capillary tube and external sensing bulb, allowing the sensing element to immediately detect temperature changes and respond by adjusting the TXV opening, thereby dramatically reducing response time while maintaining precise temperature control.
4Reliability
If brazing or soldering is required for TXV installation, then sealing is achieved, but field replacement becomes difficult
Solution Approach 1:
The permanent metallurgical joining method (brazing or soldering) is replaced with a mechanical sealing system using O-rings or other mechanical seals. This substitution maintains sealing integrity while enabling the TXV to be easily removed and replaced in the field without requiring specialized welding equipment or skills.
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 ensures uniform temperature across all cold plates, reduces system complexity, and allows for faster response times, enabling the use of advanced electronics and high-power lasers with temperature uniformity of ±2° C and full load 'turn-on' times of less than 400 milliseconds.
Implementation Method 1
Temperature changes at the outlet of the evaporator are converted to changes in working fluid pressure within the external sensing bulb
Implementation Method 2
vapor compression cooling scheme
Implementation Method 3
two-phase flow-mixture
Implementation Method 4
controls the flow to each cold plate
Implementation Method 5
action of the integral TXV (of the cold plate) via opening or closing an internal orifice
Data Source
AI summary
An apparatus for uniform cooling of a single power electronics device, an array of discrete power electronics devices or types of other heat-generating by integrating discrete thermostatic expansion devices (TXVs) and their control directly into each discrete cold plate. The thermostatic expansion device is positioned such that a sensing element is located directly within the exit refrigerant stream.