Improving Photovoltaic Efficiency
Published: Friday, November 28, 2008
Efficiency is an important factor in the research and development of Photovoltaic (PV) systems. But it does not solely depend on the quality of the system. Location, angle and maintenance also have an impact on the end result.
Kipp & Zonen is specialist in the measurement of solar radiation. We offer a range of instruments to measure the total irradiance on a plane surface. Combining the irradiance with the outcome of your PV system, gives an insight to the efficiency.
Photovoltaic (PV) relates to the application of photovoltaic cells to convert sunlight directly into electricity. The high costs of solar cells, panels and arrays keep the research into new materials and improvement of efficiency going. Monitoring the solar radiation plays an important role in analyzing both the efficiency of the cells and evaluating optimal locations for ‘solar farms’.
PV panels are specified under Standard Test Conditions (STC). These conditions are 1000 W/m2 of solar radiation, 25 ºC, Air Mass 1.5 and no wind. Because these conditions are far from the real world. Therefore additional measurements are required to show the PV panel’s typical performance. Both pyranometers and reference PV cells are used to measure the radiation. Because pyranometers have standard characteristics they can be used to independently compare all types of PV cells.
When the pyranometer is mounted at the same angle as the PV panel it can be used to calculate the panel’s efficiency. But it can also indicate failing panels or cells by a sudden drop of efficiency. A gradual decline of efficiency will indicate the need for cleaning the panels.
Kipp & Zonen CMP pyranometers provide accurate and reliable measurements for PV monitoring
Pyranometers are also used for checking PV panels and cells under laboratory conditions. Because CMP pyranometers are specified up to 80 ºC (or 150 ºC for the CM 4) they can monitor the output of the high energy lamps used in solar simulators.
Thermal energy
For thermal energy solar concentrators, and sun tracking PV systems, the direct component of the solar radiation is also required. The CHP 1 Pyrheliometer together with a Sun Tracker measures the direct radiation. Sun tracker systems measuring global, direct and diffuse radiation are often used in PV monitoring and research.
Examples of applications of Kipp & Zonen instruments in solar energy:
- Solar prospecting for optimum locations
- Radiation check for PV materials research
- Radiation check for thermal systems research
- PV and thermal power plant efficiency
- Specification and quality testing of PV panels
- Determination of losses of PV panels and reference cells
- Tests according to IEC 60904 standards
- Independent comparison of PV panels
- Solar simulator radiation verification