A solar cell production line looks like a row of clean, orderly machines. Behind it are utility systems that never stop: cooling water, ultrapure water, and wastewater treatment. If one of them fails, the line stops too, and temperature is often the first sign that something is off.
Many machines in a photovoltaic plant need cooling water, from diffusion furnaces and anti-reflective coating deposition tools to laminators and etching baths whose reactions release heat. This water usually comes from a chiller with tightly controlled temperature. Sensors on the supply and return sides show how much heat load the system is handling. If return temperature keeps climbing while production is normal, there is likely a problem with the chiller, a pump, or the flow to one of the machines.
Ultrapure water is used to rinse wafers between chemical process steps. Its quality is usually judged by resistivity, with a reference of 18.2 MΩ·cm at 25 °C. Resistivity is strongly affected by temperature, so an accurate temperature reading is needed for compensation, or the water quality may be misjudged. Feed water temperature also matters for reverse osmosis membranes: water that is too warm can shorten membrane life, while water that is too cold reduces output.
Wastewater from a solar cell plant carries leftover acids, alkalis, and fluoride from the wet processes. When acid and alkaline waste are neutralized, the reaction releases heat. Temperature monitoring in the neutralization tank helps operators adjust the chemical dosing rate so the reaction stays under control. If the treatment plant uses a biological process, temperature also has to be maintained because microorganisms only work well within a certain range.
Most utility measuring points run at low to moderate temperatures, so the RTD Pt100 is a common choice for its precision and stability. Sensor material still needs matching, for example stainless steel 316 for cooling water and an ion-free material for ultrapure water lines. In waste tanks containing fluoride or acid, a chemical-resistant protective material is still required.
Because utility systems are often housed in a separate building from the production line, the distance to the control room can be considerable. A temperature transmitter with a 4–20 mA output keeps data from every point readable at the PLC or SCADA. Alarms can then appear in the control room as soon as a temperature moves outside its set limits.
Utility systems rarely get as much attention as the production line, yet a small fault there can stop the whole plant. Installing sensors at the right points from the start costs far less than tracing the cause of a fault after production has stopped.
CV. Rach Tekindo Makmur supplies Temperature Sensors & Temperature Transmitters for a wide range of industrial instrumentation needs. If you need sensors, transmitters, or consultation on configuration and installation for your temperature system, contact us on WhatsApp at 0877-8620-5656 to discuss your technical requirements and request a quotation tailored to your application.
