A measurement system was integrated by OTM for on-site glass optical & thermal performance monitoring. The system uses off-shelf sensors and wireless data loggers and can be easily deployed for 24×7 glass performance monitoring projects.
Measurement principle
The system consists of two indoor measurement systems (reference room vs. test room) and one outdoor measurement system. Shown below are the system schematics.
The following quantities are measured:
- Indoor side (4 quantities): daylight illuminance [lux], solar irradiance [W/m2], air temperature [°C] and glass surface temperature [°C]
- Outdoor side (3 quantities): daylight illuminance [lux], solar irradiance [W/m2], air temperature [°C]
What cannot be measured?
The system is for glass optical & thermal performance monitoring only. The results are qualitatively correlated to glass visible light transmittance and solar energy transmittance.
However, it is not possible to quantitatively evaluate glass optical & thermal properties rated under standard conditions (e.g. visible light transmittance, U-value, and shading coefficient) from the monitoring results. If such quantities are required, please consider our laboratory glass testing service.
Instruments
The following instruments from Delta Ohm were used in the monitoring system:
- Wireless data loggers: HD35 wireless data logger
- Lux sensors: LPPHOT01 illuminance sensor
- Pyranometers: LPSILICON-PYRA04 silicone pyranometer
Necessary mounting accessories were included. The instruments can be conveniently installed on-site in less than 1 hour. Shown below is a photo of the outdoor side instruments in the demo installation.
Results
Shown below is a screen capture of some monitoring results (in the wireless data logger control software).
An in-house software can be used to automate the data processing part, as shown below.
Shown below are some sample results:
