HERMETIC Donates Hermetically Sealed CO2 Refrigerant Pump for Research

As part of environmental and climate protection, industrial refrigeration technology is increasingly demanding solutions that reduce direct emissions of refrigerants as well as overall energy consumption. As a result, the significance of CO₂ (R744) as a refrigerant has also increased rapidly in plant engineering. The reason: CO₂ is a natural refrigerant and environmentally friendly and cost-effective compared to the fluorinated refrigerants. CO₂ is colourless, non-toxic and non-flammable.
 

Research project: Phase change material in industrial CO₂ refrigeration systems

To reduce the energy consumption of industrial CO₂ refrigeration systems, the Energy and Process Engineering Department of NTNU in Trondheim is testing a new thermal energy storage system. The research project investigates the extent to which thermal energy can be stored at low load times in phase change materials (PCM) – also known as phase change storage or latent storage – for reuse during peak loads. Added heat accumulators should reduce the load peaks. This allows the system to be designed for a lower load level contributing to system downsizing. In this way, it is possible to significantly reduce both the acquisition costs and the ongoing energy costs of the overall system. Particularly huge potential for this technology exists in plants that have major differences in the cooling demand during the day, such as in cooling processes in the food industry. Benefits on the plant side include smaller pipe dimensions, low energy consumption for pump circulation, small pressure drop and efficient heat transfer.

High demands on the components used

A distinctive feature of CO₂ is its critical point of 31°C that requires much higher pressures for heat dissipation than are normally used in industrial cooling. This places special demands on the components used. In the pilot plant, the refrigerant CO₂ circulates in a temperature range from 5°C to –50°C with a maximum nominal pressure of 52 bar. For pump technology, it is particularly important to control the high pressure of the pumped medium. Even at normal operating temperatures, CO₂ also has a low viscosity that continues to drop as the temperature rises. This has a negative effect on the carrying capacity of the plain bearings. Other points are the required absolute tightness and a low MTBF value both demanding the highest reliability of the pump used.

HERMETIC refrigerant pump specifically designed for CO₂ applications

For the pilot plant, HERMETIC-Pumpen GmbH together with its Norwegian agent Finesterra AS supplies a multi-stage canned motor pump of the type CAMh specifically designed for CO₂ applications. This series has been developed to meet the requirements of operation at 52 bar and standstill pressure. The generously dimensioned plain bearings made of state-of-the-art sintered materials ensure contact-free and thus virtually wear-free operation of the pump. The construction and material choice of the pump series cover the nominal pressure PN 52 reliably. A pressure test at 78 bar is carried out on each pump according to valid standards such as ISO 15783 for canned motor pumps. In addition, the secondary safety containment is tested for leak-tightness using nitrogen (N₂). In this way, the HERMETIC pump ensures a reliable and controlled flow of the refrigerant in the pilot plant.

HERMETIC-Pumpen GmbH is committed to research and development

Adrian Schäfer, Product Manager for Refrigerant Pumps says: “HERMETIC pumps have advanced technologies that made us a world market leader. This is not possible without continuous investment in research, development and manufacturing. It is therefore our aim to support research at universities as well. We are interested particularly in research fields that focus on environmental protection and energy efficiency. We wish the research team every success.”

About NTNU – Norwegian University of Science and Technology

NTNU is the largest university in Norway, with an international focus, headquarters in Trondheim and campuses in Ålesund and Gjøvik. NTNU has its main profile in science and technology and, with a total of nine faculties, offers a variety of study programmes and a broad academic spectrum for around 42,000 students. Two researchers working at NTNU have received Nobel Prizes: May-Britt Moser and Edvard Moser (2014). In addition, the laureates Ivar Giæver (1973) and Lars Onsager (1968) were trained at the Norwegian Institute of Technology (NTH), one of NTNU’s predecessors. More information at www.ntnu.no
 

Background information on the CAMh series:

Performance data

Operating temperatures: –50°C to + 10°C
Flow rate: 1 m³/h to 14 m³/h
Pump head: up to 85 m
Nominal pressure: 52 bar
Test pressure: 78 bar
Motor power: 3 kW to 7.4 kW
Plain bearing material: 1.4571/W5 – 1.4571/SiC30

More information on the CAMh series: https://www.hermetic-pumpen.com/de/camh

Expert knowledge about CO₂ – written by experts for experts and users:

All you need to know about CO₂ as a refrigerant. HERMETIC – in CO₂ business for over 50 years.

Your personal copy at: https://www.hermetic-pumpen.com/en/co2