Active/passive cooling system
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Solution Overview
Problem
Current data center cooling systems face limitations in energy efficiency and require oil management, especially in high ambient temperature conditions, where heat pipes and thermosyphons are insufficient for heat rejection and pumped refrigerant systems with pumps and compressors are needed.
Innovation Solution
A cooling system that includes an evaporator, a passive condenser, and a heat exchanger, where the primary cooling medium circulates naturally between the evaporator and condenser without pumps, allowing for both passive and active modes of operation without the need for valves or oils, using natural circulation and gravity to manage refrigerant flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If heat pipes and thermosyphons are used for cooling, then energy efficiency is improved, but heat rejection is insufficient when ambient temperatures are high
Solution Approach 1:
The system dynamically switches between passive thermosyphon mode and active pumped refrigerant mode based on ambient temperature conditions and cooling demand. The pump can be turned on or off, and valves can redirect refrigerant flow to adapt to varying operating conditions, resolving the contradiction between energy efficiency and heat rejection capability.
Solution Approach 2:
The system changes operational parameters (pump operation status, valve positions, refrigerant flow paths) to transition between passive and active modes. This allows the system to maintain optimal energy efficiency in mild conditions while achieving sufficient heat rejection in high ambient temperature conditions.
2Reliability
If pumped refrigerant systems are used to improve heat rejection, then heat rejection capability is improved, but system complexity and oil management requirements increase
Solution Approach 1:
The refrigerant system is segmented into separate loops: a primary thermosyphon loop without oil and a secondary pumped loop with oil. This segmentation allows each loop to operate independently with its own optimal characteristics, reducing overall system complexity while maintaining both passive and active cooling capabilities.
Solution Approach 2:
A heat exchanger serves as an intermediary between the oil-free primary loop and the pumped secondary loop. This allows thermal energy transfer between the two systems without requiring direct mixing of refrigerants or complex integration, simplifying the overall system architecture.
3Reliability
If pumped refrigerant systems are used, then heat rejection is improved, but oil management constraints become problematic
Solution Approach 1:
The system divides refrigerant circulation into an oil-free primary thermosyphon loop and an oil-based secondary pumped loop. By segmenting the system this way, the problematic oil management issues are confined to only the active cooling mode, while the passive mode operates without oil, significantly easing operational complexity.
Solution Approach 2:
The invention extracts the oil management requirement from the primary cooling loop by using a separate secondary loop for pumped operation. This extraction allows the main thermosyphon system to operate without oil constraints, improving ease of operation while maintaining heat rejection capability through the secondary loop when needed.
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 enhances energy efficiency by eliminating the need for pumps and oils, expanding the range of suitable refrigerants, and allowing for efficient heat transfer across a wider temperature range without the constraints of oil management, thereby reducing energy consumption and operational complexity.
Implementation Method 1
change the phase of the primary cooling medium from liquid to gas
Implementation Method 2
change the phase of the primary cooling medium from liquid to gas
Implementation Method 3
transfer heat from the primary cooling medium
Implementation Method 4
change the phase of the primary cooling medium from gas to liquid
Implementation Method 5
circulates naturally between the evaporator and condenser without pumps
Implementation Method 6
using natural circulation and gravity to manage refrigerant flow
Implementation Method 7
transfer heat from the primary cooling medium
Data Source
AI summary
A cooling assembly includes an evaporator containing a primary cooling medium, a passive condenser, and a heat exchanger. When a secondary cooling medium is provided to the heat exchanger, the primary cooling medium in the gas phase switches from being received by the passive condenser to the heat exchanger without operating any valves located between the evaporator and the passive condenser and between the evaporator and the heat exchanger. The primary cooling medium circulates between the evaporator and the passive condenser and between the evaporator and the heat exchanger by natural circulation and gravity without a pump in the flow path of the primary cooling medium between the heat exchanger and the evaporator and between the passive condenser and the evaporator to circulate the primary cooling medium.