White paper with measured data

The usage profile of the system has the greatest influence on electricity consumption. Temperature cycling tests and high heat loads consume much more electricity than constant-condition tests with passive specimens. Comparing R449A systems with CO₂  systems shows a slight advantage for CO₂. Much greater savings can be achieved when comparing R23/R469A with CO₂.

CO₂ is a natural refrigerant with a GWP value of 1. This means that it has a negligible  impact on the climate compared with many commonly used refrigerants. Using CO₂  as a refrigerant, our temperature and climate test chambers meet testing requirements with lower sound pressure levels and often with reduced electricity consumption. Because of the European  F-Gas Regulation, a shift away from conventional refrigerants is necessary, and CO₂ offers a future-proof alternative.

While other providers typically showcase only proof-of-concept systems or simulations without test specimens, Weiss Technik has had production-ready CO₂ test chambers in customer field use since August 2024. These units have already completed thousands of operating hours in real-world conditions—not in labs but rather in actual daily testing operations. Since April 2025, stock units with the new CO₂ technology have also been available.

No, CO₂ is not toxic. However, like other coolants commonly used in environmental simulation, it displaces oxygen and is also invisible. The practical exposure limit for CO₂ according to DIN EN 378 is 0.07 kg/m³. This is slightly higher than for other refrigerants. For CO₂ test chambers in the reach-in range (up to 2,000 litres of test chamber volume), the refrigerant quantity is less than 3 kg, which poses a very low risk, even in the unlikely event of a leak. For every kilogram of refrigerant, a room volume of approximately 14 m³ is required.

The transcritical CO₂ systems from Weiss Technik operate at a higher operating pressure. Appropriate measures were taken during the design and construction to ensure safety:

• All components are approved by the manufacturers for the specified pressure range
• Specially trained professionals are employed in the production process
• Enhanced quality checks are conducted
• Tests in accordance with the Pressure Equipment Directive are carried out before the systems are installed and again as part of the overall system
• The entire system is tested at a higher pressure than during operation
• The system is designed to remain permanently leak-proof under all operating and storage conditions.

Yes, CO₂ is ideal for most applications. In specialized fields like aerospace, where testing is routinely performed below −50 °C, systems capable of reaching −70 °C will still be required. However, for most applications, CO₂ offers a climate-friendly, reliable and energy-efficient solution that can be achieved with the components that are currently available and the well-established transcritical CO₂ technology.

Weiss Technik not only offers technically safe, economical, and reliable CO₂ systems but also provides expert advice on optimal solutions for your laboratory. In larger labs, it may be advisable to convert only part of the equipment to CO₂ systems while continuing to operate other units with conventional systems capable of reaching temperatures below −70 °C. Weiss Technik also provides simulation software that enables detailed modeling of specific use cases in order to increase investment security.

The F-Gas Regulation requires a changeover from previously used refrigerants. Laboratory operators must familiarize themselves with the deadlines and specific requirements in order to ensure the operational safety of their laboratory. Weiss Technik provides advice on specific requirements and offers support in planning a future-proof laboratory infrastructure. The leakage test according to the F-Gas Regulation is not applicable because CO₂ is not an F-Gas.