Condenser Bypass Control for Two-Phase Cooling Dew Point Protection
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Solution Overview
Problem
Conventional two-phase pumped liquid cooling systems face issues when power electronics are indoors and the condenser is outdoors, as refrigerant fluid can condense due to cold outdoor temperatures, leading to moisture accumulation and potential damage from dripping onto electronic devices.
Innovation Solution
A valve-controlled bypass circuit is introduced to divert refrigerant flow around the condenser when the fluid pressure falls below a predetermined set-point, ensuring the refrigerant temperature remains above the indoor dew point, preventing condensation and protecting electronic devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the condenser is located outdoors to reject heat to ambient air, then heat rejection efficiency is improved, but the refrigerant fluid temperature drops below the indoor dew point causing moisture condensation on tubing and components
Solution Approach 1:
The system divides the refrigerant flow path into two separate circuits: a primary circuit that bypasses the condenser to maintain temperature above dew point, and a secondary circuit that can engage the condenser for heat rejection when needed. This segmentation allows independent control of temperature and heat rejection functions.
Solution Approach 2:
The system uses dynamic flow control valves to adjust refrigerant distribution between the bypass and condenser paths based on real-time conditions. The valve positions change continuously to maintain optimal temperature while enabling heat rejection when outdoor conditions are favorable.
2Object-affected harmful factors
If refrigerant flow is diverted around the condenser to prevent condensation, then moisture accumulation is prevented, but heat rejection capability is reduced
Solution Approach 1:
The flow control valves dynamically adjust refrigerant distribution between bypass and condenser paths based on real-time conditions. When outdoor temperatures are favorable, the system engages the condenser for heat rejection; when temperatures drop, the system shifts flow to the bypass to prevent condensation.
Solution Approach 2:
The system changes operational parameters by adjusting valve positions to control refrigerant flow distribution. This allows the system to transition between different operational modes (bypass-dominated for condensation prevention, condenser-dominated for heat rejection) based on environmental conditions.
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 effectively prevents moisture condensation on refrigerant tubing and components by regulating refrigerant flow, maintaining the fluid temperature above the indoor dew point and avoiding damage to electronic devices, even under extreme cold outdoor conditions.
Implementation Method 1
a pressure control valve adapted to selectively redirect fluid flow to bypass the condenser through a bypass fluid conduit, the pressure control valve having a predetermined pressure set-point
Implementation Method 2
A more recent cooling method utilizes a phase change fluid, or refrigerant, that will evaporate to remove heat from an electronic device heat sink
Implementation Method 3
Refrigerant fluid absorbs heat from the electronic device and partially evaporates as it flows through the cold plates 2
Implementation Method 4
The condenser heat exchanger 4 may air cooled or water cooled and it may be located indoors or outdoors
Implementation Method 5
the refrigerant fluid will leave the condenser 4 as a subcooled liquid
Data Source
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AI summary
An electronics cooling system utilizing a refrigerant fluid that evaporates to remove heat from electronics and is condensed back to liquid through heat exchange with a cold medium (air or water). The refrigerant fluid is circulated via a liquid pump between the condenser and heated evaporators. A bypass circuit is provided to divert flow around the condenser during conditions of cold ambient temperatures, which is controlled by a feedback loop using a mechanical or electronic control valve. This prevents the refrigerant fluid temperature from becoming very low and potentially inducing condensation on the outside of the refrigerant tubing from the warm and moist indoor air.