Measurement Errors When Measuring Temperature in the Sun

Area of Science:

• Environmental Science
• Building Physics
• Measurement Technology

Background:

• Microclimate simulation software validation relies on comparing simulated data with on-site measurements.
• Previous validation efforts show significant errors, especially under high solar radiation, potentially due to inadequate radiation shielding.

Purpose of the Study:

• To investigate the impact of ventilated versus non-ventilated radiation shields on temperature measurement accuracy.
• To improve the reliability of microclimate measurements for simulation software validation.

Main Methods:

• A 3D-printed ventilated radiation shield was developed and tested.
• Two pairs of temperature sensors (ventilated vs. non-ventilated shields) were deployed on a south-facing facade with varying albedo.
• Measurements were analyzed considering solar radiation, wind velocity, and facade albedo.

Main Results:

• Non-ventilated sensors showed elevated temperatures by up to 2.8 °C (high albedo) and 1.9 °C (low albedo) compared to ventilated sensors.
• The error of non-ventilated sensors was strongly dependent on wind velocity.
• Ventilated shields significantly improved accuracy under intense solar radiation.

Conclusions:

• Ventilated radiation shields are essential for accurate microclimate temperature measurements, particularly during periods of high solar radiation.
• The findings provide crucial data for enhancing the validation process of microclimate simulation software.
• This research highlights the need for improved sensor technology in environmental monitoring.