Pyranometer Forced Airflow Thermal Management
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Solution Overview
Problem
Pyranometers face challenges with zero offsets and water deposition on domes, leading to measurement uncertainties and errors, especially under moist and icy conditions, due to inadequate thermal coupling and external ventilation requirements.
Innovation Solution
A pyranometer design with a substantially closed housing and integrated ventilator that heats air to improve thermal coupling between the sensor, metal body, and domes, reducing zero offsets and maintaining a dry dome through internal ventilation, thus minimizing power consumption and maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If external pump and heat exchanger are used to cool the detector housing, then cooling effect is achieved, but device complexity and power consumption increase
Solution Approach 1:
The ventilator is integrated directly into the housing and uses the housing's own structure as the heat dissipation path. The air flow generated by the ventilator passes through the housing, cooling it internally without requiring external heat exchangers or complex cooling systems. The housing serves both as structural support and as the heat dissipation component.
2Measurement precision
If external blower is used to direct air stream across domes, then radiation measurement accuracy increases, but device complexity and power consumption increase
Solution Approach 1:
The cooling function and the measurement accuracy enhancement function are merged into a single integrated ventilator system. The same air flow that cools the housing also passes across the domes to prevent water deposition and improve measurement accuracy, eliminating the need for separate external blowers and heat exchangers.
Solution Approach 2:
The housing's own ventilator serves multiple functions: cooling the housing, preventing water deposition on domes, and improving measurement accuracy. The system uses its own resources (housing structure, internal space) to achieve these functions without requiring external辅助设备.
3Measurement precision
If inner and outer glass domes are used, then wind related signal noise and thermal offset error effects are reduced, but device complexity increases
Solution Approach 1:
The inner and outer domes serve multiple functions: they protect the sensor from wind-related noise, reduce thermal offset errors, and provide a structural framework for the integrated ventilator system. The domes are not just protective covers but active components in the thermal management and measurement accuracy enhancement.
4Reliability
If heating is applied to prevent water deposition, then data availability improves, but zero offsets increase
Solution Approach 1:
The ventilator operates continuously to maintain a steady air flow across the domes and through the housing. This continuous air flow provides ongoing cooling and prevents water deposition without requiring intermittent heating cycles that would cause temperature fluctuations and zero offsets. The system maintains a stable thermal state through continuous passive cooling.
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 design significantly reduces zero offsets and prevents dew and frost deposition at low power consumption, enhancing measurement accuracy and data availability while reducing maintenance needs.
Implementation Method 1
the air blown into the space below the outer window is heated by the ventilator power
Implementation Method 2
an integrated ventilator that heats air to improve thermal coupling between the sensor, metal body, and domes, reducing zero offsets and maintaining a dry dome through internal ventilation
Implementation Method 3
a pyranometer with a housing (2), a thermo-electric sensor (5) in said housing
Data Source
AI summary
Disclosed is a pyranometer with a housing, a sensor in the housing, an inner window and an outer dome-shaped window both overlying the sensor. An air inlet duct and an air outlet duct extend in the housing and end in a space confined by the outer window for passing air through the space, from the inlet duct to the outlet duct. The housing is substantially closed such that no outside air flows are allowed into the housing and includes a ventilator, the inlet duct being in fluid communication with a high pressure side of the ventilator, the outlet duct being in fluid communication with a low pressure side of the ventilator. The air blown into the space below the outer window is heated by the ventilator power and optionally by and added electrical heater.