A solar cell's efficiency is decided long before the panel goes up on a roof. A few degrees of difference in a chemical bath during texturing can change the wafer's surface structure, and that small change affects how much light the cell absorbs. This is why photovoltaic plants treat temperature as a process parameter just as important as chemical concentration.
The production chain is long, from polysilicon processing and wafer slicing to cell processing and module assembly. Nearly every stage has points that need temperature monitoring, but the densest demand is usually in the wet processes and the utility systems behind them.
Wet processes such as texturing, etching, and cleaning take place in baths of acid or alkaline solution. Alkaline texturing with KOH or NaOH typically runs at around 70–85 °C, so the bath has to be heated and held steady. Etching with an HF and HNO3 mixture, on the other hand, generates its own heat, so the solution has to be cooled to keep the reaction from running too fast. In both cases, the temperature sensor is the main input for the heater or chiller controller on the process bath.
After cell processing, panels are assembled and laminated. The laminator heats the stack of glass, encapsulant, cells, and backsheet to around 140–160 °C so the encapsulant melts and bonds fully. An unevenly heated plate can cause bubbles or delamination, so RTD Pt100 sensors are often placed at several points on the plate to confirm uniform heat.
Beyond the process line, a solar panel plant also relies on chillers, cooling towers, an ultrapure water system, and a wastewater treatment plant. Rising cooling water temperature can signal an overloaded chiller, while ultrapure water temperature affects the resistivity reading used to judge its purity.
Most of these measuring points connect to a PLC or DCS. A temperature transmitter converts the sensor signal to 4–20 mA so the data can travel far to the control room with little interference, then be used for alarms, trend logging, and automatic control. For plants running 24 hours a day, this trend data also helps the maintenance team spot patterns before a fault occurs.
Sensor selection in the photovoltaic industry should start from three things: the temperature range, the media in contact with the sensor, and how the signal is read by the control system. For chemical baths, the sensor's protective material matters as much as the sensing element itself.
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.
