Situation
Interest in solar power is increasing worldwide and with it, the demand for the photovoltaic (PV) modules that generate solar energy.
PV modules are exposed to environmental temperature and humidity extremes, requiring them to often perform under severe conditions. To ensure consistent performance and safety, the modules must undergo rigorous testing to meet standards set by the International Electrotechnical Commission (IEC), Underwriters Laboratory (UL) and other organizations.
Customer Challenge
Standards testing is often time consuming and expensive. It is nonetheless necessary as the resulting certifications are heavily used by the industry for procurement specifications. To prevent delays to market and increase efficiencies, solar panel manufacturers want to ensure their products will pass all standards testing the first time out.
Thermal Product Solutions (TPS), an SPX company, has long been recognized as a global leader in thermal equipment with products ranging from industrial ovens to custom pharmaceutical granulation dryers. However, it was the company’s expansive history in manufacturing environmental test chambers that led a solar panel manufacturer to approach the company with a unique challenge: develop an environmental chamber specifically for solar panel testing.
The chamber had to accommodate solar panels of a certain size and quantity, as well as a variety of intensive testing procedures. This would enable the solar panel manufacturer to “pretest” its panels, helping to ensure they would be ready for UL and IEC lab testing.
Solution
Drawing upon its expertise and track record in environmental testing and thermal processing equipment, TPS developed an environmental chamber that met the customer’s specific needs for solar panel testing.
The result is the ETC Ultimate (ETCU) series environmental test chambers, among the first environmental test chambers marketed specifically for solar panel testing. It features a large chamber space that is tailored to match standard solar panel sizes and incorporates temperature and non-corrosive humidity testing systems. It can be further customized to meet specific application and testing needs.
Built to Endure
Various models are available, with interior volumes ranging from 4 to 64 cubic feet. To withstand the rigorous testing which solar panels are subjected to, all models feature vapor-tight, continuously welded stainless steel interiors. Structural reinforcement is used at all critical points, and through-wall ports are continuously welded. A combination of fiberglass and polyurethane insulation surrounds the chamber to minimize heat transfer which could affect testing outcomes.
Since the unit’s chamber is continuously welded, the door remains as the final sealing surface to maintain atmosphere integrity. All doors are equipped with double gaskets that trap air, further insulating the unit. A unique, energy-efficient system circulates hot gas from the refrigeration system to provide automatic defrost for the door gaskets, ensuring the gaskets don’t stick and extending gasket life.
Test-Ready
For solar panel testing to be beneficial, results must be repeatable and testing conditions free of outside influences — including variations in air flow. The ETCU chambers achieve airflow uniformity by drawing air through the bottom of the workspace, conditioning it as required and then discharging it through a grille at the ceiling level. This top-to-bottom air circulation guarantees stable and consistent performance over the testing period.
The ETCU series also uses the latest in HFC environmentally friendly refrigerants, which generate much lower compressor temperatures. Multiple heating and cooling systems are available, as well as other options to accommodate specific applications and testing needs.
In Control
Solar panel testing requires close monitoring, and the ETCU test chambers puts testers in control. The chambers feature a touch screen control system, which provides precise control and monitoring of chamber operations and can be easily accessed from remote locations. Environmental conditions within the chamber can be viewed in real time on the graphical display.
A platinum RTD sensor measures temperature, while humidity is measured by an electronic, capacitive sensor (a noncontact device capable of high-resolution measurement) that requires no wet wick or water supply. The humidity system is constructed of 100% non-corroding parts and is equipped with its own low water protection system. The system operates at atmospheric pressure and is specially vented to prevent undesired siphoning.
Low-mass nichrome, open wire heating elements are used to reduce thermal lag and provide rapid response to instrument demand. The heating elements are isolated from the workspace to reduce radiant influence on the test item.
All wiring complies with National Electric Code (NEC) standards. Circuit breakers are used throughout the electrical system and are located, along with other electrical components, in a readily accessible, integral control panel.
Learn More
Learn more about the ETCU series of environmental testing chambers and for more information about other engineering design services and solutions from TPS, visit www.thermalproductsolutions.com.