Reduced power usage and CO2 footprint of Fluid-entrainment pumps

9 MIN READ

“More is more” is not true anymore. Leybold’s innovative heating system reduces the average power consumption by 15% and also provides a significantly quicker heating-up time of up to 50% as compared to conventional heating systems in Diffusion and Oil Booster pumps. The Energy Efficiency Controller achieves further reductions by regulating the heat supply for a reduced carbon footprint.

Diffusion pumps and oil booster pumps are some of the oldest high-vacuum creating technologies that are still used today. Dr. Wolfgang Gaede, German physicist and pioneer of vacuum engineering, developed the diffusion pump in 1915.

Over the following decades, fluid-entrainment pumps were further developed to optimize their pumping speed and gas throughput.

Energy requirements of fluid-entrainment pumps

However, as the gas throughput of the pumps increased, energy requirements also grew accordingly. It was quickly believed that “more is more” and heating requirements continued to increase. Even today, oil booster pumps with evaporator capacities over 50 kW are not that uncommon. When we measure the ratio of power consumption and pump performance, diffusion and jet pumps are not known to be the most energy-efficient vacuum pumps. They’re mainly used because of their exceptional performance: high pumping speed, no rotating wear parts, easy handling and are highly robust. In many fields, there’s still no other alternative, making diffusion pumps the be-all-and-end-all for many high-vacuum applications to this day.

Related: Learn more about the applications of diffusion pumps in our article When is a Diffusion Pump the Right Choice?

There are many old fluid-entrainment pumps still in the field today, often without control units and in continuous operation, that consume huge amounts of energy.

A very small proportion of the energy used by a diffusion pump is actually used for pumping. A much larger amount (approximately 80%) is used for cooling, while another 15-20% is given off as waste heat. Today, modern technology allows for significant energy consumption improvements. Modern energy-efficient pumps with control units can save up to 50% of the energy consumed as compared to older pumps.

Are diffusion pumps environmentally friendly?

Fluid-entrainment pumps (with flange sizes over 250mm) usually cannot be easily replaced with alternative high-vacuum technology as energy-efficient options such as turbomolecular pumps have a much lower pumping speed, high investment costs and are not suitable in many applications as they are simply not robust enough. It’s estimated that there are around 25,000 diffusion pumps installed in industrial facilities. And globally, the use of outdated, inefficient pumps contributes significantly to environmental pollution. The carbon footprint of this technology can however be considerably improved through modernization.

Optimizing diffusion pumps for improved energy efficiency

Optimizing diffusion pump performance and operation

Most manufacturers still use the old heating system – plates with either heating coils, heating plates or other heating elements screwed beneath the pump’s evaporator chamber. Their energy efficiency is already reduced by having to first heat the oil through the pump’s conductive resistant solid base. A large proportion of the energy used is also lost to the environment via the sides and sub-floor.

The innovative heating system in Leybold’s diffusion and oil booster pumps allows for significant improvements by bringing the heating unit into the evaporator vessel with the oil. This reduces any thermal loss due to contact resistance with other external heating elements. All heat given off goes directly into the pump oil and energy loss is further reduced by additional insulation on the evaporator chamber. These measures alone reduce the average power consumption by 15% when compared with conventional heating systems. Another advantage of direct heating is the significantly quicker heating-up time, which is up to 50% less than conventional plate or segment plate heating systems. Also, depending on the application and owing to its shorter heating-up time, the pump can be switched on at very short notice, meaning additional power savings.

Reduced operating costs and CO2 emissions with Leybold’s energy efficiency controller

Diffusion pumps only require their full heating capacity during the heating phase. During normal operation or while in stand-by, around 30-70% less energy is actually required. Traditionally, however, pumps operate continuously at full heating capacity, causing more oil to evaporate and then condense than is actually necessary for the required suction power. “More is more” is not true anymore, as more power does not provide any additional pumping capacity.

Using the Energy Efficiency Controller developed by Leybold can also deliver potential further savings:

The control unit continuously measures oil vapor temperature, keeping it at the constant heat level required. If the evaporator chamber is hot enough, the heat supply will be regulated, and power consumption significantly reduced.
Due to reduced power consumption, the life of both the heater and the pump fluid is extended. Heat stress on wearing parts is also reduced by the power-controlled pump operation, increasing service life proportionally. This also reduces maintenance costs across the board.
Since, on average, less oil vapor is produced, less oil vapor also needs to condense on the inner walls of the pump, which can also mean savings on the cooling system. The temperature of cooling water is regulated, so that less cooling water is used when there is less oil condensing. This lowers both cost and indirect carbon emissions.

Related: Learn more in our article Vacuum Pumps may Cost More than you Think: Here are 5 Ways to Save

Benefits that innovative Leybold diffusion pump technology can bring to your production

Example: Operation of a 50,000 l/s diffusion pump over an average 20-year service life (approx):

Heating output

24 kW

Operating period

6,400 hours/year

Total power consumption

1 year: 153,600 kWh

20 years: 3,072,000 kWh

Modernization savings (40%)

1 year: 61,440 kWh

20 years: 1,228,800 kWh

CO2 savings*

1 year: 24.6t

20 years: 493t

Operating cost savings**

1 year: €8,300

20 years: €166,000

Assuming an average heating capacity of 10kW for units installed all over the world, modernizing them with fluid-entrainment pumps could reduce global CO₂ emissions by over 6 million tons!

Related: Check out these 5 Tips to Keep your Diffusion Pumps Running Smoothly.

Conclusion:

For years, Leybold has been consistently pursuing the development of fluid-entrainment pump technology, so that this technology can be suitable for the manufacture of environmentally compatible products both now and in the future.

Both plant operators and OEMs should ask whether the fluid-entrainment pump technology they’re using, or planning to use, is state-of-the-art. Using cutting-edge products can result in large cost savings and an improved carbon footprint.

Operators should also inquire as to whether they’re eligible for funding by making their production more energy efficient. Many states support the use of energy-efficient products with both tax breaks and bonuses.

*German power mix 2021: 401g CO2 per KWh (Source “Strom Report Blog”)

**Average cost of industrial electricity in Germany: €0.135/kWh