Solmetric PVA-1000S, Руководство пользователя

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6 Measuring Irradiance, Temperature, and Tilt
6-8
A good choice for this application is high-temperature polyester tape (for example:
Kapton). The tape should be approximately 2 inches wide, so that you can capture not
just the tip of the thermocouple, but also an inch of the thermocouple lead. This tape is
also available from Solmetric in spools of 1.75-inch disks for added convenience.
Do not use cheap duct tape, as it sags when hot, allowing the thermocouple tip to pull
away from the surface.
Attaching the thermocouple to the module backside
Cut a fresh 2” length of tape or use a fresh tape disk. Place the thermocouple bead in the
center of the tape. Press the tape firmly against the backside of the PV module, applying
pressure first over the thermocouple, then over the thermocouple lead, and then press
down the rest of the tape. Press once more on the thermocouple bead to be sure it is in
firm contact with the module.
When testing flush mounted arrays, you will be reaching under modules to attach the
thermocouple. Since you can’t inspect the attachment, it’s a good idea to practice your
technique on a free-standing module. Make sure that your tape is always fully adhered,
and that the thermocouple bead is always firmly pressed against the surface. If there is a
wrinkle in the tape at the location of the thermocouple bead, start over.
Choosing a location to mount the thermocouple on the module or array
Even on a windless day with steady irradiance, there will be a temperature gradient
across the module or array, with the edges typically run cooler than the middle. Some
guidelines apply.
When testing a single, isolated, tilted-up module, mount the thermocouple on a diagonal
line of the module, 2/3 of the distance from the corner to the middle of the module.
Experience has shown this to be representative of the average cell temperature.
When testing a flush-mounted array in which you have access only to the outer modules,
mount the thermocouple at the middle of a module. If you are reaching under from the
narrow end of the module, mount the thermocouple as far under as you can comfortably
reach and manage a good attachment.
When testing a tilt-up array, mount the thermocouple well away from the edges of the
array.
If you are measuring multiple subarrays, strings, or modules and plan to compare their
results, your comparison will be more reliable if you always mount the thermocouple in
the same relative position. Even though the resulting temperature may not exactly
represent the average cell temperature, you will at least avoid introducing a random,
location-related temperature error to the family of measurement results.