Loop Heat Pipe Startup Control via Vapor Line Heating
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Solution Overview
Problem
Loop heat pipes fail to start up effectively when the evaporator is positioned below the condenser, leading to inefficient energy consumption and delayed cooling due to fixed heating times and varying working fluid distribution profiles, especially in portable devices where the positional relationship and attitude change.
Innovation Solution
A loop heat pipe system with a temperature sensor and controller to monitor and heat specific parts of the vapor line, ensuring efficient startup by detecting condensation changes and optimizing heating times based on temperature measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the evaporator is positioned below the condenser, then the loop heat pipe can be installed in portable devices with space constraints, but the loop heat pipe fails to start up efficiently and requires fixed heating times that waste energy
Solution Approach 1:
The patent applies dynamics by making the heating time variable rather than fixed. The controller dynamically adjusts the heating duration based on real-time temperature sensor feedback, allowing the system to adapt to different operating conditions and working fluid distributions, thereby reducing energy waste while maintaining reliable startup in portable devices with evaporator below condenser configuration
Solution Approach 2:
The patent implements feedback control by using temperature sensors to monitor the vapor line temperature during startup and feeding this information back to the controller. The controller continuously adjusts the heating operation based on the temperature feedback, optimizing the heating process to achieve startup with minimal energy consumption while accommodating the evaporator-below-condenser installation configuration
2Reliability
If fixed heating time is used to ensure startup, then the loop heat pipe can start up reliably, but the start timing is delayed more than needed and energy is wasted
Solution Approach 1:
The controller uses temperature sensor feedback to determine when startup is achieved, allowing the system to stop heating as soon as the working fluid begins to circulate. This feedback mechanism ensures reliable startup detection while minimizing unnecessary heating time, thus resolving the contradiction between startup reliability and startup delay
Solution Approach 2:
Instead of applying excessive fixed heating time to ensure startup, the system applies partial heating action by monitoring temperature conditions and stopping heating as soon as startup is detected. This prevents over-heating and unnecessary delays while maintaining startup reliability through condition-based control
3Volume of moving object
If the evaporator is positioned below the condenser, then the device can be compact, but working liquid does not exist in the evaporator and the loop heat pipe does not start up
Solution Approach 1:
The patent applies preliminary action by heating the vapor line before activating the heat source to induce working liquid circulation. This preliminary heating action causes the working liquid to move from the condenser to the evaporator, ensuring the evaporator contains working liquid before the cooling function is activated, thus enabling startup in compact configurations with evaporator below condenser
Solution Approach 2:
The patent applies preliminary anti-action by counteracting the gravitational effect that prevents working liquid from reaching the evaporator when it is positioned below the condenser. By heating the vapor line in advance, the system creates vapor pressure that pushes the working liquid upward against gravity into the evaporator, enabling the loop heat pipe to start up in compact vertical configurations
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 allows for efficient startup of the loop heat pipe, reducing energy consumption and ensuring timely cooling by dynamically adjusting heating based on temperature changes, thereby improving the operational efficiency and reliability of portable information processing devices.
Implementation Method 1
an evaporator to evaporate working liquid (a liquid phase of a working fluid) by adsorbing heat from a heat source
Implementation Method 2
a condenser to condense vaporized working liquid (vapor phase of a working fluid) by radiating heat
Implementation Method 3
attach a heater to part of the vapor line (a part of the vapor line near the evaporator) and to heat, by using the heater, the part of the vapor line
Data Source
AI summary
A loop heat pipe system includes a loop heat pipe (LHP), a temperature sensor, a heater and a controller. The temperature sensor measures temperature of a working fluid portion of the LHP in which the working fluid has different phases depending on whether or not the LHP is in a disable status not to start up a heat transportation, in which a liquid phase of the working fluid does not exist in an evaporator of the LHP. The heater heats a heating target part of a vapor line. The controller, in order to start up the LHP, turns on the heater, monitors temperature of the heating target part using the temperature sensor, and turns off the heater when detecting a change in the monitored temperature, caused by condensation of a vapor phase of the working fluid.