Panel or module temperature sensors play a crucial role in photovoltaic (PV) installations, contributing to the overall efficiency and performance of solar energy systems. These sensors are designed to monitor the temperature of solar panels, providing useful data to optimize energy production and ensure the sustainability of the solar installation.
Module temperature sensors are placed at the back of Module (BOM) to measure the temperature of the photovoltaic cells. The data collected by these sensors is then transmitted to the system’s monitoring unit for analysis.
Where Should a Module Temperature Sensor Be Installed According to IEC 61724-1?
As per IEC 61724-1 :2021 Standard:
“The Module temperature sensor location should be at the center of a cell close to the center of module, avoiding boundaries between cells. “
Based on established standards, the type of sensor recommended for permanent measurement of module surface temperature is equipped with flat probes specifically designed for prolonged surface measurements. In accordance with these specifications, SEVEN SENSOR manufacturing process involves the production of module temperature sensors with flat probes constructed from resilient materials that withstand the impact of temperature variations, humidity and ultraviolet radiation.
What Are the Technical Requirements Defined in IEC 61724-1:2021?
In the 2021 update, Section 9.1 of the IEC 61724-1 discusses the temperature of PV modules, stating that:
- For bifacial modules, rear-side temperature sensors and wiring shall obscure < 10 % of the area of any cell, and wiring should be routed in between cells when possible.
- Temperature sensors shall have a measurement resolution ≤ 0.1 °C and uncertainty ± 1 °C or better.
This requirement aligns with the SEVEN Module Temperature Sensor, which is available with two different encapsulation methods. The PT1000 probe can either be encapsulated with ABS plastic injection or laminated between EVA film and a Tedlar Backsheet. The EVA laminated structure of the 3S-MT-PT1000 module temperature sensor shares similar heat transfer characteristics with the back of PV modules. Both models feature a resolution of ≤ 0.1 °C and an uncertainty of ±0.1 °C, which makes them compliant with Class A requirements according to IEC 60751:2022.
Why Is Module Temperature Important in PV Installations?
Performance Optimization
One of the main reasons why module temperature sensors are essential is their role in optimizing the performance of solar panels. From a technical standpoint, the performance ratio (PR) of a photovoltaic installation is closely linked to the module temperature. In other words, for an accurate calculation of the PR, it is essential to obtain exact measurements of the module temperature.
Where Tmod is the Temperature of the BOM measured by 3S-MT-PT1000.
Photovoltaic cells are sensitive to changes in temperature and their efficiency decreases as the temperature rises. By monitoring the temperature of the panels, adjustments can be made to maximize energy production under varying environmental conditions.
Preventing Overheating
Excessive heat can reduce the efficiency of solar panels and damage them in the long term. Module temperature sensors provide real-time data, enabling the system to implement cooling mechanisms or adjust the angle of the panels to prevent overheating. This proactive policy maintains optimum operating conditions, guaranteeing constant energy production.
Durability of the System
High temperatures can lead to accelerated solar panel degradation over time. By constantly monitoring Module temperatures, system operators can implement actions to reduce thermal damage. This contributes to the sustainability of the photovoltaic system, protecting the investment and reducing maintenance costs.
Adjustments to Weather Conditions
Solar panels are exposed to changing weather conditions, including temperature fluctuations. Module temperature sensors provide real-time data that can be used by monitoring or control systems to evaluate system performance under varying environmental conditions.
In general, module temperature sensors support photovoltaic installations by contributing to:
- Performance optimization
- Thermal risk monitoring
- Long-term system durability
As the solar industry progresses, these sensors are becoming essential to the efficiency and operation of panels, making their implementation vital to unlocking the full potential of solar energy systems.
Frequently Asked Questions (FAQ)
How many module temperature sensors are required in a PV plant?
IEC 61724-1:2021 determines the required number of module temperature sensors based on plant size and monitoring class. The standard recommends distributing sensors so that each representative array, inverter section, or module type is properly covered. Larger utility-scale plants require a higher number of sensors to ensure accurate performance monitoring. More details about sensor selection and quantity requirements according to IEC 61724-1:2021 are explained in How to Select Sensors and Quantities for PV Plant According to IEC 61724-1:2021.
What types of outputs can SEVEN Module Temperature Sensors provide?
SEVEN Module Temperature Sensor are available with different output options depending on the selected model, including analog 4–20 mA, analog 0–10 V, PT1000 output (Can be connected to the SEVEN Irradiance Sensor and Sensor Box), or digital Modbus RTU (RS485).
Why are PT1000 sensors commonly used in module temperature measurement?
PT1000 elements offer high accuracy, stability, and linear response across a wide temperature range, making them ideal for PV module temperature measurement per IEC 60751 and IEC 61724-1 performance criteria.