Loughborough University
Leicestershire, UK
LE11 3TU
+44 (0)1509 222222
Loughborough University

Centre for Renewable Energy Systems Technology (CREST)

Applied Photovoltaics

Solar Resource & PV Performance Monitoring

The CREST-APV group has operated long term meteorological and PV performance monitoring since 2003. These systems are used for publicly funded research, commercially funded contracts with solar companies and internal work to validate software models. Our monitoring systems are located on the roof of a three storey building with clear southern aspect to minimise measurement uncertainties due to shading. All measurement devices are regularly calibrated against traceable standards to assure accuracy of measurements.

The rooftop monitoring area is also home to a radio telescope operated by the physics department and an Ampair wind turbine with met mast operated by the CREST Wind & Water Power Research Group.


Meteorological monitoring

Irradiance measurements have been recorded at 10-second resolution since 2003 and 5-second resolution since 2007. Measurements are taken at higher resolution (1-2 seconds) for short campaigns during specific projects. Solar irradiance is measured with thermopile and semiconductor pyranometers at 35 and 45 degrees tilt (South-facing) and in the horizontal plane. We have a Kipp & Zonen Solys-2 precision tracker for measurement of beam and diffuse irradiance components. Diffuse irradiance is also measured with a pyranometer and shadow band  for comparison. High quality Kipp & Zonen CMP11 and CMP21 pyranometers are used with CVF4 ventilation units.

Spectral irradiance is measured in the horizontal and on inclined arrays with EKO MS700 spectroradiometers (350-1050 nm band), supported by measurements of different material reference devices including mono- and poly-crystalline silicon, micro-morphous silicon and CIS.

Other measured parameters include wind speed & direction (ultrasonic sensor), ambient temperature and humidity.


PV device measurements

CREST-APV continues to operate the UK's highest accuracy outdoor PV module measurements, due to regular maintenance and calibration to traceable standards.

We currently have three PV monitoring systems, suitable for different types of PV device and measurement conditions, with channel capacity for over 100 devices. On our flagship system, full I-V curves are measured at 1-minute resolution with timestamps synchronised with the meteorological measurements. Between I-V sweeps, modules are electrically connected to individual maximum power point trackers to replicate normal operating conditions. Ambient and module temperatures are measured at 5-second resoluton.

We have facilities to monitor modules at various fixed tilt orientations or on a two-axis sun tracker.