Server Rack Spray Cooling via Evaporative Phase Transition
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Solution Overview
Problem
Conventional server rack cooling systems rely on inefficient air-based cooling methods, leading to high energy consumption and thermal resistance issues, which can result in elevated component temperatures and reduced performance.
Innovation Solution
A closed-loop spray cooling system where dielectric coolant is distributed as fine droplets to absorb heat from electronic components, vaporized, and then condensed by a central condenser, eliminating the need for chillers and reducing airflow requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional air-based cooling is used, then the cooling system can operate with simple equipment, but energy consumption increases and thermal resistance causes elevated component temperatures
Solution Approach 1:
The patent transitions from air-based cooling to liquid-based spray cooling. Nozzles deliver fine droplets of coolant directly to heat-producing components, utilizing fluid dynamics to achieve efficient heat transfer. This hydraulic approach replaces the conventional air circulation system with a liquid spray system that maintains lower energy consumption while effectively removing heat.
Solution Approach 2:
The patent utilizes evaporative cooling where liquid coolant droplets absorb heat from components and transition to vapor phase. The vapor is then condensed by a central condenser, completing a phase change cycle. This phase transition mechanism enables highly efficient heat removal with lower energy input compared to conventional air cooling.
2Stress or pressure
If air cooling is used with limited airflow velocity, then pressure drop and noise are controlled, but thermal resistance increases requiring larger temperature differential
Solution Approach 1:
The patent employs liquid spray instead of air flow to transfer heat. The liquid droplets are delivered directly to hot spots through nozzles, eliminating the need for high-velocity airflow. This hydraulic cooling method achieves superior heat transfer coefficients without the pressure drop and noise issues associated with forced air cooling.
Solution Approach 2:
The patent introduces liquid coolant as an intermediary substance between the heat-producing components and the cooling system. This intermediary fluid provides a much higher heat transfer coefficient compared to air, enabling effective cooling with minimal temperature differential and without requiring high airflow velocities that cause pressure drop and noise.
3Reliability
If chilled air is supplied at low temperature, then cooling reliability improves, but energy requirements in cooling equipment increase
Solution Approach 1:
The patent utilizes the phase change from liquid to vapor as the primary cooling mechanism. The evaporative cooling process occurs at or near ambient temperature, eliminating the need for energy-intensive chillers that must maintain low temperatures. The phase transition absorbs large amounts of latent heat, providing reliable cooling without the high energy input required by conventional chilled air systems.
Solution Approach 2:
The cooling system uses the heat itself to drive the cooling process. The heat from components causes the liquid coolant to evaporate, and this evaporative process self-regulates based on the thermal load. The system adapts automatically to varying heat loads without requiring energy-intensive active cooling equipment, achieving reliable cooling through self-regulating evaporative processes.
4Temperature
If local fans are added to reduce convective resistance, then cooling of high-power components improves, but energy consumption increases
Solution Approach 1:
The patent replaces air-based convective cooling with liquid-based spray cooling. The liquid droplets deliver heat directly to components through phase change, achieving superior cooling performance without requiring additional fans. This eliminates the need for energy-consuming local fans while effectively managing high-power component temperatures.
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 maintains uniform temperatures, increases IT performance and component reliability, and achieves higher heat flux removal with lower energy consumption, potentially reducing Power Usage Effectiveness (PUE) below 1.2.
Implementation Method 1
at least one nozzle in fluid communication with the coolant reservoir. The at least one nozzle may be configured to deliver fine coolant droplets into the interior volume of space for impingement on the heat-producing-electronic-components
Implementation Method 2
coolant vapour generated from impingement of the fine coolant droplets on the heat-producing-electronic-components
Implementation Method 3
at least one fan configured to generate an air-vapour flow within the interior volume of space and through the two or more open-frame-server-units from a front of the server rack enclosure to the rear of the server rack enclosure in a manner so as to carry coolant vapour generated from impingement of the fine coolant droplets on the heat-producing-electronic-components to the central condenser
Data Source
AI summary
A server rack cooling arrangement may include a server rack enclosure defining a single undivided interior volume of space and configured to be sealable; two or more open-frame-server-units disposed within the interior volume of space and arranged in a multi-level arrangement, wherein heat-producing-electronic-components may be exposed to environmental conditions of the interior volume of space; a central condenser disposed towards a rear; a coolant reservoir for collecting condensate from the central condenser; at least one nozzle in fluid communication with the coolant reservoir and configured to deliver fine coolant droplets into the interior volume of space for impingement on the heat-producing-electronic-components; and a fan configured to generate an airflow through the two or more open-frame-server-units from a front to the rear in a manner so as to carry coolant vapour generated from impingement of the fine coolant droplets on the heat-producing-electronic-components to the central condenser.