Part-time Active Cooling for HID Lamp Restrike Time
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Solution Overview
Problem
High intensity discharge lamps face long restrike times due to the need for high starting voltages when hot, which is costly and risky, and full-time cooling systems are impractical for industrial and outdoor applications due to expense and contamination concerns.
Innovation Solution
A part-time active cooling system that circulates air around the lamp's outer jacket using a fan, synthetic jet, heat pipe, or liquid cold plate, controlled by a thermal sensor and control device to speed cooling only when the lamp is off and above a predefined temperature, eliminating the need for high starting voltage ballasts and external air circulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a ballast provides high starting voltage to restart the lamp when hot, then the lamp can be restrike faster, but the ballast becomes expensive and has safety issues
Solution Approach 1:
The cooling system is activated before the restrike attempt to pre-cool the lamp and arc tube, reducing the temperature and pressure to levels where standard voltage can successfully restrike the lamp. This preliminary cooling action eliminates the need for expensive high-voltage ballasts.
Solution Approach 2:
A thermal sensor acts as an intermediary to monitor the lamp temperature and control the cooling system activation. The sensor provides feedback to the control device, which then activates the cooling system at the appropriate time to enable successful restrike with standard voltage.
2Loss of time
If a full-time cooling system is used to reduce restrike time, then the lamp cools faster, but the system becomes expensive to operate and may introduce contaminants
Solution Approach 1:
The cooling system operates periodically rather than continuously, activating only during the interval between lamp shutdown and restrike attempt. The control device monitors lamp state and thermal sensor data to determine when cooling is necessary, eliminating energy waste during normal operation.
Solution Approach 2:
The cooling system provides sufficient cooling action only when needed for restrike, rather than maintaining constant cooling. This partial action approach reduces energy consumption while still achieving the goal of reducing restrike time to an acceptable level.
3Temperature
If a full-time cooling system circulates air from the surrounding environment, then cooling efficiency improves, but contaminants may be introduced into the luminaire
Solution Approach 1:
The cooling system is designed to perform multiple functions: it can draw air from the surrounding environment when the lamp is off and cooling is needed, and it can switch to internal air circulation when the lamp is operating or when contamination risk is present. This multi-functionality allows the system to adapt to different operational requirements.
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
Reduces restrike time without expensive ballasts or full-time cooling, maintaining safety and reducing costs by operating the cooling device only when necessary, thus enhancing lamp reliability and efficiency.
Implementation Method 1
a circulating device circulates air around the outer jacket of the lamp
Implementation Method 2
A thermal sensor senses the temperature at a point inside the housing
Data Source
AI summary
Systems and methods for reducing lamp restrike time are provided. In a lighting apparatus having a housing, a reflector, and a lamp positioned so that at least a portion of the outer jacket of the lamp is within the reflector, a circulating device is operated when the lamp is off and a temperature inside the housing is above a predefined temperature. The circulating device circulates air around the outer jacket of the lamp to cool the lamp so the restrike time is reduced without the need for a starting device with a starting voltage high enough to restart the lamp when the lamp is hot.