How does Weiss Technik compare to other providers with CO2 systems?

While other providers usually only present proof-of-concept systems or simulations without test specimens, Weiss Technik has had near-series CO2 test chambers in field use at customer sites since August 2024. These have already completed thousands of operating hours in real customer use – not under laboratory conditions, but in actual testing environments. Since April 2025, storage units with the new innovative CO2 technology have also been available.

Is CO2 as a refrigerant dangerous for laboratory personnel?

No, CO2 is not toxic. Like other commonly used refrigerants in environmental simulation, it is oxygen-displacing and invisible. The practical limit according to DIN EN 378 is 0.07 kg/m³ for CO2 – even higher than for other refrigerants. In CO2 test chambers in the reach-in range (up to 2,000 liters of test space), the refrigerant quantity is less than 3 kg, which presents a very low risk even in the unlikely event of a leak. About 14 m³ of room volume is required per kg of refrigerant.

Is the high operating pressure of CO2 systems problematic?

Weiss Technik's transcritical CO2 systems operate at higher operating pressures. To ensure safety, the following measures were taken during design and construction: - All components are approved by manufacturers for the pressure range - Specially trained personnel are used in production - Enhanced quality controls are conducted - Pressure equipment directive tests are performed before system installation and again on the complete system - The entire system is tested at a pressure higher than during operation - The system is designed to remain permanently sealed under all operating and storage conditions.

How does Weiss Technik support the transition to CO2 refrigerants?

Weiss Technik not only provides technically safe, economical, and reliable CO2 systems but also advises customers on appropriate scenarios for their laboratories. In larger labs, it may be advisable to convert only part of the systems to CO2 while keeping others with conventional systems operating below -70°C. Additionally, Weiss Technik currently offers simulation software to help model specific use cases, increasing investment security.

What legal regulations must laboratory operators comply with?

The F-Gas Regulation requires a transition from previously used refrigerants. Laboratory operators must familiarize themselves with deadlines and specific requirements to ensure the operational safety of their laboratories. Weiss Technik provides guidance on these requirements and supports the planning of a future-proof laboratory infrastructure. The leakage test required by the F-Gas Regulation is not necessary, as CO2 is not an F-Gas.

New CO2 refrigeration technology

Q: Why does Weiss Technik use CO2 as a refrigerant?

CO2 is a natural refrigerant with a GWP value of 1, meaning it has a negligible impact on the climate compared to many other refrigerants. With CO2 as a refrigerant, our temperature and climate test chambers meet testing requirements with lower noise levels and often reduced energy consumption. Due to the European F-Gas Regulation, a transition from conventional refrigerants is necessary, and CO2 offers a future-proof alternative.

Q: Is CO2 the refrigerant of the future?

Yes, for most applications. In specialized fields such as aerospace, where routine testing is conducted below -50°C, systems with ultra-low temperatures are still required. However, for the majority of applications, CO2 offers a climate-friendly, reliable, and energy-efficient solution, made feasible by the now available components and mastered transcritical CO2 technology.

New refrigeration technology: what has changed, what has remained the same

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New refrigeration technology with more power in the low temperature range

Our new CO₂ refrigeration technology achieves a test chamber temperature of up to −50°C in our climate chambers and temperature chambers. It is more powerful in the low temperature range than the previous −40°C refrigeration technology. At the critical point of −40°C for many test standards, the new refrigerating units still provide considerable cooling capacity and heat compensation. Traditional, single-stage refrigeration technology can hardly cool test specimens below −30°C.

In all Weiss Technik test chambers, the previous −40°C refrigeration technology is being replaced by new CO₂-based refrigeration technology without changing the design, connections, and dimensions of the units. The environmental parameters also remain the same. Infrastructure such as cooling water, connectors, and accessories can continue to be used. Only a few technical parameters have changed.

Advantages of the new CO2 refrigeration technology

Power reserve

The performance parameters are determined with an empty test space according to IEC 60068-3-5. The cooling rate is specified in the range of 10–90% of the temperature range. Thanks to the CO2 low temperature of −50°C, the test chamber will maintain the specified cooling rate down to at least −27°C (temperature range 180°C to −50°C corresponds to 230 K. 10% is 23 K. −50°C + 23 K = −27°C).

Not affected by F-Gas Regulation

Natural refrigerants such as CO2 are not F-gases. The EU directives therefore do not apply to CO2 refrigeration systems. Many recording obligations, quota regulations, and repair regulations no longer apply. Leakage tests are required only according to EN 378 and no longer according to the GWP value. Carbon dioxide as a refrigerant is given a GWP of 1.

−70°C cascade refrigeration is often no longer necessary

Many relevant test standards such as IEC 60068-2 contain preferred temperatures (e.g. −40°C). At this temperature point, previous single-stage units with R449A no longer have any cooling capacity. Users had to resort to cascade refrigeration systems with two refrigeration circuits. These are complex and therefore more expensive. Our cost-effective CO2 refrigeration still has sufficient cooling capacity/heat compensation even in the low temperature range.

Noise level

Climatic chambers and temperature chambers are a source of noise in the laboratory. Compressors and switching valves generate a disturbing noise. Components for CO2 refrigeration technology are considerably smaller and quieter with the same output. The housing fan is now often the loudest component. Because it typically only runs sporadically, CO2 test chambers are barely audible. The noise level is regularly below 50 decibels (quieter than in the office).

Notes on CO2 refrigeration

New: Fuses with 300mA required due to frequency converters

The cooling water temperature remains the same: 12-28°C.

Ambient temperatures of up to 35°C are no problem.

The dimensions, size and footprint of all appliances remain the same.

The new Simpac 2.0 controller has a ring buffer, Linux, and NTP.

An electronic cooling water regulator allows a lower water pressure.

The new CO2 refrigeration technology can cool down to -50°C.

Power consumption and power consumption are lower than before.

Lower sound pressure level: CO2 refrigeration has smaller, quieter components.

IEC 60068-2-14 Nb: Sufficient heat compensation in the holding phase at -40°C. No cascade system necessary.

System pressure up to 120 bar, but significantly smaller cross-sections and volumes. No problem with the Pressure Equipment Directive.

CO2 has GWP1 and is not flammable.

Changes during commissioning

Practical limiting value

The maximum permissible gas concentration in an occupied zone is determined by the practical limit value. Carbon dioxide has a higher value than R449A. A unit requires 14 m³ of installation space (0.072 kg/m³) per kilogramme of CO2 filling quantity. Nowadays, typical areas for test chambers with a floor area of 2 × 3 m and a ceiling height of 3 m are still sufficient. Alternatively, a warning device can be fitted.

Leakage current

Our CO2 refrigeration systems use frequency converters to control the compressors. The resulting leakage currents sometimes exceed the usual 30 mA in households. Although our units do not have to be protected with RCDs, many electrical installations contain such a fuse. In these cases, we recommend the use of fuses with a tripping current of 300 mA as required by the manufacturers of the frequency converters.

S!MPATI® software

The convenient programming, control, and recording with our S!MPATI® software naturally also works with our new CO2 refrigeration technology. However, because the units are equipped with the new, improved S!Mpac 2.0 control system, additional port releases are required in the network.

Tightness test

In accordance with the EU F-Gas Regulation, leak tests are prescribed depending on the GWP value and the amount of refrigerant. CO2 is not an F-gas and is therefore not covered by this regulation. We recommend an annual leak test carried out according to DIN EN 378-4 in order to fulfil the requirements regarding protective measures for work equipment in accordance with the German Health and Safety at Work Regulations.

Comparison of the unit parameters

Parameter	previous −40°C class	new CO2 refrigeration
Refrigerant GWP	1397	1
Energy consumption		lower
Sound pressure level		quieter
Rate of temperature change, cooling guaranteed up to	−18°C	−27°C
Temporal temperature deviation	0.1–0.5 K	0.1–0.5 K
Spatial temperature homogeneity	0.5–1 K	0.5–1 K
Cooling water temperature	12–28°C	12–28°C
Ambient temperature	28/35°C	28/35°C
Footprint		identical
Installation room (practical limit value)	2.8 m³ per kg R449A	14 m³ per kg CO2
Pressure equipment category	None	None
S!MPATI® ports		additionally 62542 for ASCII 2050 & 2051

Currently available and next-generation units

Type / Test Space	-40°C class (not available from 2025 anymore)	CO2 class (available)	-70°C class (available)
LabEvent (temperature / climate)
20 litres		on request	--
34 litres	5 K/min	4 K/min (-40°C)	5 K/min (-70°C)
64 litres	3 K/min	3 K/min (-40°C)	3 K/min (-70°C)
100 litres	5 K/min	4 K/min (-50°C)	3 K/min & 10 K/min (-70°C)
150 litres	5 K/min	4 K/min (-50°C)	3 K/min & 10 K/min (-70°C)
110/210 litres	3 K/min	3 K/min (-50°C)	3 K/min & 5 K/min (-70°C)
500 litres	3 K/min	3 K/min (-50°C)	3 K/min (-60°C)

ClimeEvent & TempEvent
180 litres	3 K/min & 5 K/min	3 K/min	3 K/min & 5 K/min
340 litres	3 K/min & 5 K/min	3 K/min	3 K/min & 5 K/min
600 litres	3 K/min & 5 K/min	4 K/min	3 K/min & 5 K/min
1000 litres	3 K/min & 5 K/min	10 K/min	3 K/min & 5 K/min
1500 litres	3 K/min & 5 K/min	7 K/min	3 K/min & 5 K/min
2000 litres	3 K/min	on request	3 K/min
270 litres	10, 15, 20 K/min	2025	10, 15, 20, 25 K/min
480 litres	10, 15, 20 K/min	2025	10, 15, 20, 25 K/min
800 litres	10, 15, 20 K/min	2025	10, 15, 20, 25 K/min
1300 litres	10, 15, 20 K/min	2025	10, 15, 20, 25 K/min

XXL 1600 litres	3 K/min & 5 K/min	>4 K/min (-50°C)	3 K/min & 5 K/min
XXL 2450 litres	3 K/min & 5 K/min	>3 K/min (-50°C)	2 K/min & 4 K/min
XXL 3400 litres	3 K/min & 5 K/min	>2 K/min (-50°C)	2 K/min & 4 K/min

Walk-in (9m³ - 21m³)	2 K/min	>2 K/min (all -50°C)	>2 K/min (all -70°C)

The performance values are measured according to IEC 60068-3-5 in the range of 10–90% of the entire temperature range.

All our appliances with special functions will also be available with CO₂ refrigeration from 2025:

ShakeEvent
SunEvent
AirEvent Gas & AirEvent Ozone
Constant climate chambers
R-chambers

Many rapid coolers (>10 K/min) are available with CO₂ and are measured on request.

All models are available on request without F-gas, some with longer delivery times.

Downloads

Refrigerants I F-gas Regulation Overview

FAQ

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Saving energy with CO₂ refrigeration technology

Factsheet: Comparison of electricity consumption and CO2 emissions

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Additional links

Text of the EU Regulation

Regulation 2024/573 of the European Parliament and of the Council

Read now

F-Gas FAQ

Announcements from Weiss Technik on the F-Gas Regulation

Read now

Exemption -50°C

EU implementing regulation 2024/2729

Read now

EU Implementing Regulation

Certification of service technicians and commissioning engineers

Read now

FAQ

Why does Weiss Technik use CO2 as a refrigerant?

CO₂ is a natural refrigerant with a GWP value of 1, which means that it has a comparatively negligible impact on the climate compared to many other refrigerants currently in use. Using CO2 as a refrigerant allows our temperature and climate test chambers to meet testing requirements at lower sound pressure levels and typically with reduced energy consumption. The European F-Gas Regulation requires a changeover from conventional refrigerants, and CO₂ offers a future-proof alternative.

How does Weiss Technik compare to other providers of CO2 systems?

While most suppliers typically present only proof-of-concept systems or simulations without test specimens, Weiss Technik has had production-ready CO₂ test chambers in use by customers since August 2024. These chambers have already accumulated thousands of operating hours in real-world conditions, demonstrating their effectiveness in day-to-day testing rather than under laboratory conditions. Since April 2025, storage units with the new innovative CO2 technology have also been available.

Is the use of CO2 as a refrigerant dangerous for laboratory staff?

No, CO₂ is not toxic. However, like other coolants commonly used in environmental simulation, it displaces oxygen and is also invisible. The practical limit for CO₂ according to DIN EN 378 is 0.07 kg/m³ – which is even 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.

Is the high operating pressure in CO2 systems problematic?

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
Intensified quality controls 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.

Is CO2 the refrigerant of the future?

Yes, for most applications. In specialised fields such as aerospace, where routine testing is conducted below -50 °C, systems capable of achieving ultra-low temperatures below -50 °C will continue to be required. However, for the majority of applications, CO₂ offers a climate-friendly, reliable and energy-efficient solution that can be realised with the components that are currently available and the well-established transcritical CO₂ technology.

How is Weiss Technik helping with the switch to CO2 refrigerants?

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 laboratories, it may be advisable to convert only part of the systems to CO₂ while continuing to operate others with conventional systems for temperatures below -70 °C. Weiss Technik also provides simulation software to simulate specific applications, enhancing the security of your investment.

What legal requirements must laboratory operators observe?

The F-Gas Regulation requires a changeover from previously used refrigerants. Laboratory operators must familiarise 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 CO₂is not an F-Gas.